Supporting industries across the world through precision technology “Always challenging what is new, and creating new value” Achieving “the precision infi nitely close to zero error” to fulfi ll customers’ requirements for high accuracy and high productivity in every fi eld of industry ● Ball screw related manufacturing locations is the basic and primary focus of product manufacturing at KURODA. ● Precision machining technology KURODA, based on its strong commitment to precision and its craftsman’s DNA that dictates it “make the things it needs using its own faculties”, has developed a large number of underlying technologies originating from its legacy as a gauge manufacturer ranging from measurement techniques to machine tools such as proprietary surface grinding machines Kazusa Akademia Plant (Chiba) Asahi Plant (Chiba) and in-house-developed thread grinding · Precision Ball Screws · Rolled Ball Screws machines. KURODA’s products manufactured · Support Units · Ballscrew Actuators from these underlying technologies have become essential in a wide range of fields, such as machines, cars, medical care, and semiconductors.
● More than 90 years of history Since its foundation in 1925, KURODA has Futtsu Plant (Chiba) JENAER GEWINDETECHNIK GmbH (Germany) continuously supported many industries with · Ball Screw-Related Components · Precision Ball Screws reliable technologies related to “precision”. The relationships, trust, mutual technologies, ● Overseas locations and know-how KURODA has accumulated over these 90 years of history make it a highly credible company.
● Global network In recent years, KURODA has accelerated its global expansion to support industrial advancement all over the world through precision technology. As part of this effort, KURODA has entered into United States KURODA JENA TEC INC. partnerships including the acquisition of the South Korea KURODA PRECISION INDUSTRIES KOREA LTD. China KURODA PRECISION INDUSTRIES PINGHU CO., LTD. JENATEC group and will continue to expand KURODA JENA TEC PRECISION INDUSTRIES PINGHU CO., LTD. its overseas sales organization to make the Malaysia KURODA PRECISION INDUSTRIES(M) SDN.BHD. Germany JENAER GEWINDETECHNIK GmbH KURODA brand and KURODA-JENATEC brand better known in the world. Introduction-3 KURODA aspires to the principle of “CHALLENGE & CREATE”, making KURODA supports high precision applications using materials linear motion systems based on expertise in gauge manufacturing. and equipment that can achieve JIS lead accuracy grade C0.
KURODA’s Ball Screws Materials and Heat Treatment KURODA’s Ball Screws are an outgrowth of a legacy in KURODA makes it a rule to purchase dedicated ball screw gauge manufacturing. materials based on detailed specifications intended for our In order to obtain characteristically advantageous features company and internally control the heat treatment processes such as high efficiency in motion control, KURODA’s ball such as carburizing, quenching and induction hardening, of screws are utilized as an essential element in the control which records are carefully kept to assure traceability. mechanism of a wide variety of automatic machines including machining tools, precision positioning tables, industrial robots, and semiconductor fabrication devices.
High Quality Standards Grinding In recent years, the technical development of various machines for KURODA uses high precision thread grinders dedicated higher accuracy and higher speed has been increasingly accelerated for ball screws developed and manufactured uniquely and the users’ needs are much more diversified than ever. On the by KURODA based on its screw gauge manufacturing strength of our traditional precision machining technology and our know-how. These are carefully maintained at KURODA to unceasing research into ideal ball screws, we are supplying high enable ball screw manufacturing with JIS C0 grade high quality ball screws that are manufactured from carefully selected accuracy. These machines realize the world’s highest materials especially in terms of quality with our advanced grinding level of machining precision due to the combination of a technologies and under our extremely tight quality control using the vast machining database built up over a half-century with most modern test and measuring equipment. KURODA’s highly proficient technicians.
Research and Development Assembly Responding to rapid diversification of needs, KURODA The ball screw shafts, nuts, and recirculation parts that were has been pursuing more research and development on ball machined to a high accuracy are meticulously assembled screws by looking ahead to the advancement of precision and finished through excellent work by experienced workers. engineering technology for the next generation. We are The axial clearance and preloading are strictly administered conducting intensive studies into the basics of ideal ball to realize a smooth operability and high positioning accuracy screws jointly with academic laboratories to accumulate and that satisfies the requirements of a variety of machines and analyze comprehensive test data on the accuracy, hardness, equipment. service life, and other vital factors of ball screws, and have established various evaluation systems.
Inspection Machining Center Cylindrical Grinding In order to assure stable measurement at JIS C0 grade lead accuracy, we have established a structure including our proprietary lead measuring machine installed in a strictly Forming Grinding controlled thermostatic chamber as well as measuring
Design machines classified by applications so as to satisfy any Shipment Assembly Programming Functional Test
Heat Treatment needs for various applications and measurement accuracies Dimensional Inspection Additional Machining Non-destructive Test covering all processes from development to mass Lathe, Milling Machine Thread Grinding production.
Introduction-4 Introduction-5 BALL SCREWS AND LINEAR MOTION PRODUCTS KURODA products can support your linear motion systems. KURODA will recommend the optimal linear motion system which satisfies To fulfill a variety of needs and requirements of our customers, your needs. we provide a wide selection of products including ball screws, linear motion products, and related tools and equipment.
Standard Precision Ball Screws Ballscrew Actuators
■ Ball screws with C3 accuracy A ballscrew actuator is a product in which ball screws and grade linear motion guides are integrated in one unit. GP series (ø8 - ø20 mm) Please refer to KURODA’s ballscrew actuator catalog. DP series (ø6 - ø14 mm) ■ Actuators with repeated positioning accuracy of ±1 μm ■ Ball screws with C5 accuracy (P grade) and ±3 μm (H grade) grade SG series (Mounting height: 20-55 mm) GG series (ø8 - ø32 mm) FG series (ø10 - ø25 mm) HG series (ø8 - ø20 mm)
■ Ball screws with C7 accuracy grade GE series (ø8 - ø32 mm) Related Products FE series (ø10 - ø25 mm) ■ Actuators with repeated positioning accuracy of ±3 μm GW series (ø8 - ø25 mm, with ■ Support units (H grade), ± 5μm (U grade) and ±10 μm (W grade) rolled screw shaft) Square type BUK series SE series (Mounting height: 15-45 mm) RW series (ø8 mm, resin nut) (Bearing inner diameter: ø6 - ø25 mm) Square type BUKE series (Bearing inner diameter: ø6 - ø12 mm) ■ Ball screws with C10 accuracy grade Round type BUM series GY series (ø8 - ø40 mm, with rolled screw shaft) (Bearing inner diameter: ø6 - ø25 mm) Round type BUT series (Bearing inner diameter: ø20 - ø40 mm) Custom Precision Ball Screws ■ Full-cover type actuators ■ Low particle generating grease SC series (Mounting height: 23-45 mm) ■ Ball screws with C0-C10 KURODA C-Grease (Clean grease) Couplings and Other Related Products (Repeated positioning accuracy: ±3 μm (H grade), ±5 μm accuracy grades KURODA S-Grease (Clean and oscillation-proof grease) (U grade) and ±10 μm (W grade)) GR series (ø5 - ø125 mm) ■ Couplings DR series (ø6 - ø50 mm) ■ Lubricating unit for ball screws Miki Pulley Co., Ltd. LUBSEAL (Applicable shaft diameter: ø10 - ø25 mm) http://www.mikipulley.co.jp/JP/ ■ Ball screws with C3-C7 Sakai Manufacturing Co., Ltd. accuracy grades ■ Slide screws with resin nuts http://www.sakai-mfg.com/ FR series (ø10 - ø40 mm) PW series (Accuracy grade C7, ø10, ø12 mm) ISEL Co., Ltd. PY series (Accuracy grade C10, ø10, ø12 mm) http://isel.jp/
Introduction-6 Introduction-7 Ball Screws Product Range Ball Screws Product Range
Features and Accuracy Accuracy Series Nut combination Shaft diameter Screw shaft type Product line Features and keywords Series Nut combination Shaft diameter Screw shaft type Product line keywords grade grade FG series C5 Unfinished shaft Standard GP series C3 ø8 to ø20 One end finished · High rotational speed Single nut ø10 to ø25 Standard · Low noise FE series C7 ends product GG series Single nut C5 F series · Wide variety of shaft diameters ø8 to ø32 Unfinished shaft ends product · Compact Single nut C3 to C7 ø10 to ø40 Custom · Wide variety of lead sizes GE series C7 FR series Free design G series · Long service life Double nut C3 to C5 ø32 to ø40 product · For positioning Single nut C0 to C7 ø5 to ø125 Custom · For transfer GR series Integral nut C0 to C5 ø20 to ø63 Free design product Double nut C0 to C5 ø8 to ø125
Features and Accuracy Series Nut combination Shaft diameter Screw shaft type Product line keywords grade Accuracy Features and keywords Series Nut combination Shaft diameter Screw shaft type Product line DP series Single nut C3 ø6 to ø14 One end finished Standard product grade · Compact D series Single nut C0 to C7 ø6 to ø50 · Fine-pitch positioning DR series Free design Custom product · For transfer GW series C7 ø8 to ø25 Standard Integral nut C0 to C5 ø16 to ø50 Rolled · Wide variety of nut types Single nut Unfinished shaft ends rolled G series (round and square types) GY series C10 ø8 to ø40 product
Accuracy Features and keywords Series Nut combination Shaft diameter Screw shaft type Product line Accuracy Shaft grade Features and keywords Series Nut combination Screw shaft type Product line grade diameter · High speed conveyance H series HG series Single nut C5 ø8 to ø20 Unfinished shaft ends Standard product · For transfer Unfinished shaft Standard rolled · Large lead R series RW series Single nut C7 ø8 · For lighter load applications ends product
Introduction-8 Introduction-9 Products Related to Ball Screws Data including product information, technical information, catalogs, and CAD data of linear motion products such as ball screws and Support units ballscrew actuators can also be viewed from the KURODA website. Features and Bearing Bearing inner Series Bearing type Accuracy grade of bearing keywords combination diameter Square type BUK series Combined angular ball P5 grade (P0 grade for · Compact body DF (face-to-face) ø6 to ø25 · Fit for any mounting Round type BUM series bearing deep groove ball bearing) www. kuroda-precision.co.jp confi gurations High-thrust angular ball Round type BUT series DF (face-to-face) P4 grade ø20 to ø40 · Built-in locking bearing function Square type BUKE series Radial ball bearing --- P0 grade ø6 to ø12
BUK (Square type) BUT (Round type) BUKE (Square type) BUM (Round type)
Low particle generating grease
Operating Features and keywords Series Thickener Model number temperature range KURODA C1-080G-J (Supplied in a 80 g bellows-shaped container) ᴾ ᴾ · For clean environment -30 to +150°C Urea 2D CAD data 3D CAD data · Excellent lubricating performance C-Grease C1-400G-J (Supplied in a 400 g bellows-shaped container) · Excellent torque performance KURODA S1-080G-J (Supplied in a 80 g bellows-shaped container) 2D CAD data (DXF format) can be 3D CAD data can be downloaded free of -20 to +150°C Urea · High rust prevention performance S-Grease S1-400G-J (Supplied in a 400 g bellows-shaped container) downloaded free of charge from the charge from the PARTcommunity CAD KURODA website. data downloading service. Slide screws with resin nuts
Nut Accuracy Shaft Screw shaft Features and keywords Series Product line combination grade diameter type
· Precise resin nut PW series C7 · Excellent mechanical property Unfi nished Standard · Chemical-proof performance Slide screw Single nut ø10, ø12 shaft ends product · Compact PY series C10 · Low price
Catalogs
The catalogs of ball screws, ball screw linear motion products, ballscrew actuators
and other products can be downloaded from the KURODA website. For pamphlets, please contact your nearest sales location.
Introduction-10 Introduction-11 Proper usage for safety Be sure to read the following instructions before use. For general instructions, refer to the text of this catalog. ball screws ball screws Overview of Overview of The following safety precautions recommend the correct usage of our products to prevent an injury and damage. These precautions are classified into 3 categories: DANGER“ ”, “WARNING” and “CAUTION” KURODA Ball Screws Catalog according to the degree of possible injury or damage and the degree of impendence of such injury or damage. Be sure to follow all these precautions, as they contain important matters regarding safety. Proper usage for safety― ――――――――――――――――― A- 2 to 4 DANGER WARNING CAUTION Features of KURODA ball screws― ―――――――――――― A- 5 Indicates an impending hazardous Indicates a potentially hazardous Indicates a potentially hazardous Construction, materials and heat treatment―――――――― A- 6 situation that may arise due to situation that may arise due to situation that may arise due to improper handling or operation improper handling or operation improper handling or operation Types―of―nuts―and―flanges― ―――――――――――――――― A- 7 and could result in a serious injury and could result in a serious injury and could result in an injury or or death. or death. property damage only. Custom products― ―――――――――――――――――――― A- 8 to 9 Be sure to obey “Industrial Safety and Health Act” and other safety rules and regulations in Ordering instructions (How to interpret ball screw model numbers) A-10 to 13 addition to these precautions. There are some situations that may lead to a serious result according to circumstances, even if it is mentioned in the category of “CAUTION”. Be sure to follow these precautions, as they contain important matters. WARNING ●―Select a ball screw properly. As operating conditions for products mentioned in this catalog are diverse, the applicability of ball screw to the intended system should be determined by the total system designer or the person who determined specifications for such system after conducting analysis and testing as necessary. The person who determined the applicability of the system shall be responsible for assuring the intended system’s performance and safety. When configuring a system, the system designer should thoroughly examine all specifications for such a system by referring to the latest product catalog and data, and also take into consideration the possibility of equipment-related issues. ●――The ball screw should be handled by persons who have sufficient knowledge and experience. · Thoroughly read this catalog and operation manual before use. · Never disassemble the ball screw. Dust may enter inside, degrading the accuracy of the ball screw and may lead to an accident. When the ball screw has been disassembled from necessity, return it to KURODA for repair and reassembling. (Fees will be incured.) · When mounting a ball screw to a machine and dismounting it from the machine, check that a means of fall prevention has been put in place and that the moving part of the machine has been fixed beforehand. ● The products listed here are primarily for industrial use. When using the ball screw in the following conditions or environments, take the proper safety measures and consult KURODA beforehand. · Conditions and environments other than specified and outdoor use. · Applications to nuclear power equipment, railroads aircraft, vehicles, medical equipment, equipment contacting food and drink, and the like. · Applications which require extreme safety and will also greatly affect persons and property. ● During operation, make sure to keep your hands away from screws and ends of ball screw shafts, which are rotating parts, to prevent your hands from being caught. ● Pay adequate attention not to allow the products to be used for military purpose including for arms and weapons.
A-1 A-2 Ball screw/General instructions (1) Ball screw/General instructions (2) Be sure to read the following instructions before use. Be sure to read the following instructions before use. Also refer to “Proper usage for safety”. Also refer to “Proper usage for safety”. ball screws ball screws Overview of Overview of ●―Mounting―of―the―ball―screw ●―Be―careful―of―any―dust―or―contaminants. Caution for design When mounting of the ball screw to a machine, the While a machine is assembled, put a cover to prevent Storage system design should allow its screw shaft to be the screw shaft from catching any dust or contaminants. WARNING mounted without taking off the nut. Removing and Such contamination could cause malfunction of the CAUTION attaching the nut may cause some balls to drop machine. ●―Storage―method ●―Rotational speed outside of their recirculation path, which may result in Referring to the section describing permissible ●――When― a― component― such― as― bearing,― gear,― or― Store the ball screws in an indoor place where damage of recirculation components. If such removal pulley is attached to a screw shaft, handle them temperature difference is as small as possible, rotational speed in this catalog, use a ball screw at of a nut is inevitable, consult KURODA beforehand. or lower than the listed permissible rotational speed. with care so that there is no damage from impact. avoiding high and low temperatures and high humidity. Using the product at or above the permissible Such impact could cause the screw shaft to bend. It should be stored in a horizontal state in the If an impact is accidentally applied to the shaft, packaging originally sent by KURODA. In order to rotational speed could cause damage of its Caution for mounting and use recirculation components and result in inoperable check it first to see if it is not bent by checking the prevent unnecessary contamination by dust or conditions. When using a vertical shaft, the damage coupling of the screw shaft with a dial gauge, before rusting of the ball screws, do not open the outer may lead to dangerous accidents such as falling WARNING assembling the additional components. packaging or any of the internal packaging unless balls or parts. ●――Use―the―product―within―the―operating―temperature―limit. necessary. ●―Do―not―overrun―the―product. Ball screws are designed to have a normal operating If a nut of the ball screw is overrun and receives an temperature limit of 60°C or below. Using them in an impact at a stroke end, a resulting impression created Checkup and caution CAUTION environment exceeding the temperature limit may on a screw groove could cause malfunction. If an end ●―Dust―preventive―cover result in a damaged lubrication or sealing components. of the screw groove has a portion with no flute, such If it is likely that dust or other contaminant may enter If you need to use the screw in a special environment, overturn could damage ball recirculation components, CAUTION inside the ball screw, be sure to attach a dust consult with KURODA beforehand. which may result in inoperable conditions. ●――Checking the lubricant status and application of grease preventive cover, such as bellows or lead screw If a ball screw nut has been allowed to overrun, For the sake of usability and dust prevention, cover (steel bellows). Attaching a wiper at both ends please contact KURODA to have it repaired at charge. lubricant for ball screws is, in general, contained only of a nut will be more effective for dust prevention. Lubricants in the nut. When specified or required for overseas The dust or contaminant caught in the ball screw ●―Pay―adequate―attention―to―the―accuracy―grade. export, lubricant may be applied to the screw shaft. could cause various defects including malfunction, A moment load caused by misalignment of a ball CAUTION Depending on the screw size and screw shaft length, abnormal noise, excessive vibration, accelerated screw, bearing, guide, nut, and housing and improper the amount of grease in the nut may not be sufficient. wear-out, and early chipping. angularity may result in malfunction, abnormal noise, ●―Type―of―lubricant After running the nut back and forth the length of the excessive vibration, shorter product service life as Unless specified, Alvania Grease S2 or Maltemp PS shaft, check to see if the rolling side of the screw well as breakage of screw shafts due to rotating Dust preventive No.2 is contained in the nut as lubricant. Since rust groove has enough grease on it. If the amount is not Lead screw cover bending fatigue. Be careful with such defects because device preventive oil applied to the screw shaft also serves enough, apply additional grease to the screw shaft. they may lead to a serious accident. as lubricant, the ball screw can be used without ●―Checkup―and―reapplication―of―lubricant ●――Be―careful―with―falling―off―of―components―due―to― additional application. Check the lubricant 2 to 3 months after the ball screw their own weight. Do not replace the initially applied lubricant with any is used for the first time. If it is extremely dirty, it is Since a ball screw has a low friction factor, its shaft or recommend that you wipe off old grease and apply product not listed below. Do not remove the rust nut could potentially fall off due to its own weight. Be new grease. Then, check and supply the lubricant once careful not to have your hand or fingers be caught preventive oil, either. every year as a general rule. However, as the service under the fallen component. life of lubricants varies according to operating conditions Bellows Grease ●―Take―care―not―to―injure―yourself. Application Product name Manufacturer and environment, adjust the intervals properly. Wiper Resin wiper, lip seal, The shafts and nut corners may have sharp edges for brush wiper Alvania Grease S2 SHOWA SHELL SEKIYU Felt wiper structural reasons, and there may be a risk of injuries General K.K. When reapplying additional lubricant, use the same purpose such as cuts. Multemp PS No. 2 Grease KYODO YUSHI CO., LTD. brand of lubricant as was initially included. In order to prevent injuries, take adequate care when For a ball screw model provided with a nut which does KURODA C-Grease KURODA PRECISION handling products and wear protective equipment INDUSTSRIES LTD. not have a grease filler hole, supply a sufficient amount such as gloves during work. For dust of grease directly to the screw shaft and screw groove, prevention KURODA S-Grease (Support for oscillation KURODA PRECISION carefully applying it over the components until the resistance) INDUSTSRIES LTD. grease goes into the nut. For a model provided with a CAUTION nut having a filler hole, supply a necessary amount of ●―Do―not―remove―the―nut. Lubricating oil grease from the filler hole or a feeder (grease nipple, ●―Imbalanced―load When balls have dropped out of the nut or the nut has Application Product name Manufacturer etc). In your system design, ensure that a radial or been removed from a shaft, do not attempt to IDEMITSU KOSAN CO., After applying additional grease, run the work for a full Daphne Mechanic Oil moment load is not directly loaded to the ball screw. reassemble them yourself. Return them to KURODA General LTD. stroke to ensure the proper coverage of the grease on Otherwise, it may result in shorter product service for repair. (Fees will be incured.) purpose EXXON MOBIL all components. Wipe off excess grease attached on life due to concentrated load to a certain portion of KURODA’s standard precision ball screws have Mobil Vactra Oil CORPORATION the end of the screw shaft. balls in the screw. unfinished shaft ends. The unfinished products are Note) All product names of greases and oils are registered trademarks of their For more details on the size of the filler hole, refer to provided with a sleeve for separating the nut. respective companies. dimensions of each ball screws size.
A-3 A-4 ball screws Construction Ball screws are configured to have steel balls enclosed between a Tube Method screw shaft and a nut, wherein steel balls rotate while they recirculate Pick-up Tube Excellent reliability and Excellent durability in the device.
ball screws ball screws are designed to adopt one of the following ball screws Overview of ball screws maintain excellent Overview of high accuracy durability achieved by carefully selected four standard recirculation systems. ball screws provide high materials, proper heat treatment, and machining accuracy as well as excellent reliability, as a ■―Tube―Method with advanced product technologies. result of our grinding, assembly, and inspection This is a standard recirculation system for ball screws, using a curved tube as a recirculation part. In this system, steel balls are guided into operations implemented in our plants under a End Cap Method strict temperature control, which is built on our Small axial clearance the tube, make 1.5, 2.5, or 3.5 turns along the screw groove to return End Cap Since ball screws adopt a gauge production expertise accumulated over to the starting point, forming a circuit. gothic-arch groove profile, its axial clearance many years. To enhance the load capacity of the screw, the number of circuits can can be finely adjusted and rotated with minimal be increased. force. In addition, by applying preload to the High transmission screw, the axial clearance could be adjusted to ■―End―Cap―Method 0 to achieve advanced rigidity. This recirculation system has end caps attached to both ends of the efficiency nut, which are capable of scooping up the steel balls and forwarding Ball screws have outstanding transmission them back to the starting point. A through hole is provided in the body Deflector Method efficiency of over 90%, incomparably higher of the nut to allow the steel balls to pass through. This system is Deflector (metal) than slide screws. Their required torque is just adopted by ball screws with large leads (e.g. screw lead with twice or less than a third of what slide screws require. three times as large as the screw shaft diameter). Therefore, it is easier to transfer linear motion into rotary motion. ■―Deflector―Method This system is compact and has the most optimal rotational balance μ=0.003 100 μ=0.005 among the recirculation systems listed in this catalog. Steel balls μ=0.008 90 μ=0.010 rolling between a screw shaft and a nut are guided by a deflector End Deflector Method End Deflector 80 Ball screw Figure 2: Ball screw groove profile inserted in the nut to make one recirculation per lead, forming a 70 Rotary → Linear circuit. μ=0.1 Fine feeding 60 Due to rolling contacts made by balls, the ball ■―End―Deflector―Method 50 μ=0.2 screws can accurately provide fine feeding, This system has end deflectors incorporated into both ends of the 40 μ=0.3 even with extremely small starting friction at nut, which are capable of scooping up steel balls and forwarding Efficiency η (%) 30 Slide screw low speed, without exhibiting the stick slip them back to the starting point. A through hole is provided in the (Trapezoidal body of the nut to allow the steel balls to pass through. The system is 20 tendency of slide screws. screw thread) designed for a smooth flow of the steel balls. This structure realized Figure 3: Recirculation 10 higher rotational speed and low-noise operation in a compact nut system μ: Coefficient of friction High-speed operation 012345678910 With high transmission efficiency and a low body. Lead angle (degree) rate of self heat generation, KURODA ball Table―1:―Materials―and―heat―treatment μ=0.003 100 μ=0.005 screws can provide a high speed rotation. ● Ground ball screws μ=0.008 Materials―and―heat―treatment 90 μ=0.010 The hardness of the screw groove surface is a Material Heat treatment Hardness 80 Ball screw critical factor for the service life of a ball screw. Chromium-molybdenum steel Carburizing and 58 to 62 Easy maintenance Nut SCM420 quenching HRC 70 Due to rolling contacts made by balls, no special The rigidity of the shaft must satisfy the require- Linear → Rotary Chromium-molybdenum steel maintenance other than regular supply of grease ments of a shaft for transmission of loads. In SCM415 Carburizing and 58 to 62 60 quenching HRC is required under normal operating conditions. order to fulfill such needs, KURODA ball screws Screw SCM420 50 shaft μ=0.1 are generally manufactured to maintain the Chromium-molybdenum steel Induction 58 to 62 40 Slide screw AISI4150HV quenching HRC Efficiency η (%) (Trapezoidal Wide variation minimum standard hardness of 58 HRC with the 30 screw thread) In order to fulfill a diverse range of customer materials listed in Table 1. The screws also go ● Rolled ball screws 20 requirements there are a wide variety of series through a surface hardening process to enhance Material Heat treatment Hardness 10 and models of ball screws their hardness to attain 58 to 62 HRC. Addition- μ: Coefficient of friction S45C Induction made available. Products include miniature ally, for some products which required heat re- Screw shaft S55C quenching 56 to 62HRC 012345678910 ball screws, super large lead ball screws, sistance and/or corrosion resistance, stainless Lead angle (degree) Nut SCM420 Steel balls 58 to 62HRC high rotational speed ball screws, standard steel may be used to achieve hardness of 56 to Steel ball SUJ2 Quenching 60 HRC or Figure―1:―Mechanical―efficiency―of―ball―screws precision ball screws and more. 59 HRC through a surface hardening process. above
A-5 A-6 Types Custom products ■―Nut―combination―types Single Nut In order to fulfill the diversified needs of our customer in various industries such as mounting/ placement machines, semiconductor fabrication equipment, liquid crystal (LC) manufacturing ball screws This is the simplest configuration. It is usually used ball screws Overview of Overview of with a small axial clearance. In order to improve the machines, clean robots, SEM equipment, small machine tools, medical instruments, automotive positioning accuracy, axial clearance can be eliminated production facilities, etc., provides, upon your request, various customized and a preload can be applied by loading oversized ball screws with special specifications. Our custom products include super precision ball balls. The single nut type with a preload is suitable for screws (C0 grade or above), high rotational speed ball screws, stainless ball screws for machines requiring small to medium loads and light to special environments, low maintenance ball screws, and ball screws compliant with various normal preloading, including semiconductor fabrication environmental requirements. devices, assembling robots, precision instruments, and small NC machine tools, which require very high ■― ――Super―precision―ball―screws― positioning accuracy. (capable―of―fine―pitch―forwarding―by―a―scale―of―0.1―μm/pulse) Integral Nut When a machine requires fine feeding with high accuracy, torque variation contributes to This type of nut has a screw portion separated into a accuracy degradation. With a laser scanner, SEM instrument, and test/analysis equipment, load side and preload side via a pitch shift. The nut is torque variation causes fluctuations in the transfer speed of the machine. Under such conditions, offset according to the desired amount of preload. It a highly accurate continuous operation may provides the features of having a load side and preload not be achieved. However, building upon Dynamic preload torque precision processing expertise acquired side of a double nut integrated in one component. 5 The integration into one body enables the nut to be through years of gauge production business, 1N·cm has successfully developed in- shorter while maintaining stable rigidity and excellent N·cm 5 380mm operational performance. house screw grinders to control the profile of The integral nut is suitable for all types of machines the screw groove, circularity, and cylindricality Shaft diameter: 15 and equipment requiring medium to higher loads and in a highly accurate manner. With the reduced Lead: 5 Rotational speed for measurement: 50 min-1 normal to higher preloading. torque variation achieved by this precise control, we have realized ball screws capable Lubricant: Turbine oil #2 (ISO VG68) Double Nut of fine feeding by to a degree of 0.1 μm/pulse. Two separate nuts, one designated as the load side and the other as the preload side are joined. They are rotated ■― ――Super―precision―ball―screw― in opposite directions and fixed in tension by a pin inserted (entire―deflection―of―a―screw―shaft―is―1/4―to―1/3―of―C0―grade―screw) between them. A double nut is available in wider variety As long as the deflection of the screw shaft is within the permissible range and the shaft is kept of sizes than integral nuts, and is suitable for applications straight though a typical mounting arrangement where rigid linear bearings are set at both ends with medium to higher preloading and with medium to of the ball screw, there is usually limited influence on operational accuracy. However, in such higher loads, such as machines or equipment requiring cases that a simplified guiding system has been put in place for weight or size considerations, highly precise positioning as well as high rigidity. bending of the ball screw may adversely impact operational accuracy, resulting in pitching or yawing errors. To prevent such issues, provides customized ball screws ■―Flange―types manufactured through our unique processing method, with which the deflection of the screw The type of a flange is represented by a symbol provided for each nominal size as shown below. shaft center is mitigated to 1/4 to 1/3 of permissible deflection for C0 grade screws. For more Type symbol A B C information, please contact . ■―High―rotational―speed―ball―screw KURODA provides special ball screws capable of fulfilling our customers’ needs for rotational Flange type speed with a DmN of over 70,000. These ball screws are suitable for use in machine tools, robots, and other applications requiring high rotational speed. The F series is the standard Square flange Rectangle flange Round flange product line designed for high rotational speed and low noise. Custom products in the G series Type symbol D E H can also be designed to meet the DmN requirements of high speed applications. For more information, please contact .
Flange type
Single side cut, round flange Square (without spot facing) Double side cut, round flange
A-7 A-8 ■―Ball―screw―compliant―with―special―environmental―requirements ●―All-stainless―steel―ball―screw Ordering instructions (How to interpret ball screw model numbers) Shaft Number Nut Flange Ball Re- Wiper Thread Overall Shaft Thread Accuracy Axial Stainless steel ball screws which can be used Materials of all-stainless steel screws Series Lead circulation Screw Shaft Model Diameter of Circuits Type Type System Material Direction Length End Type Length Grade Clearance in vacuum atmospheric conditions, clean room · Screw shaft, nut, and balls Martensitic stainless steel number FE 15 10 P S − HPNR − 1500 X 1440 − C5 F conditions, or an environment with special Austenitic stainless steel,
ball screws (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) ball screws Overview of requirements such as chemical resistance, · Recirculation components precipitation hardening Overview of are also available. The stainless steel screws stainless steel, etc. (1) Ball Screw Series · Small screws and parts Austenitic stainless steel Series Standard series Order-made series Remarks demonstrate minimal outgassing and excellent * Order-made Ball Screws are indicated with □R, □M, F Series FE/C7 grade, FG/C5 grade FR, FM, FZ/C3-C7 grades and □Z which designate the following: corrosion resistance. □R: Order-made Ball Screws with established D Series DP/C3 grade DR, DM, DZ/C0-C7 grades KURODA specifications and design. Details are For more information, please contact . GE/C7 grade, GG/C5 grade, GP/C3 grade GR, GM, GZ/C0-C10 grades listed in this catalog. G Series □M: Customized Order-made Ball Screws with GY/C10 grade (rolled screw), GW/C7 grade (rolled screw) GT/C7 or C10 grade (rolled screw) established KURODA specifications and design, but with a customized flange. H Series HG/C5 grade − □Z: Customized Order-made Ball Screws with ●―Customized―surface―treatment specifications and design other than the above. If you intend to use a ball screw in an environment where corrosion resistance is necessary, R Series RW/C7 grade − GT indicates customized rolled ball screws. (2) Screw Shaft Diameter (unit: mm) (3) Ball Screw Lead we can accommodate your needs by applying an additional anticorrosive black coating for Indicated by a two-digit number or a number-alphabet combination. Indicated by a two-digit number or a number-alphabet combination. rust-proofing. The black coating has a thickness of 1-2 μm. Some of the coating may be · To show a screw shaft diameter with a 1-digit number, 0 needs · To show a lead with a 1-digit number, 0 needs to be added in partially removed from areas subjected to consistent ball contact during the initial period after to be added in front of the diameter to make it a two-digit code. front to make it a two-digit code. (Example) Screw shaft diameter 5 mm → 05 (Example) Lead of 1 mm → 01 commencement of operation, but rust prevention will be maintained thereafter. If you need more · Screw shaft diameters with 3-digits are indicated as follows: · Leads whose actual value is not a whole number (i.e. including advanced corrosion resistance, further additional fluorine coating on top of the anticorrosive 100 mm → A0, 125 mm → C5 an increment of 0.5 mm) are represented with the letter F as black coating can be applied. Other types of surface treatment will also be provided upon indicated below. 1.5 mm → 1F, 2.5 mm → 2F request. (4) Number of Circuits of the Ball Screw Nut For more information, please contact . Symbol Number of circuits Applicable recirculation system Symbol Number of circuits Applicable recirculation system A 1.5 turns, 1 circuit H 1 turn, 2 circuits B 1.5 turns, 2 circuits J 1 turn, 3 circuits ■―Ball―screws―with―lubricating―unit C 1.5 turns, 3 circuits K 1 turn, 4 circuits Deflector method LUBSEAL is a lubricating unit attached to the ball screw nut which supplies a proper amount D 2.5 turns, 1 circuit L 1 turn, 5 circuits Tube method of grease to the screw groove. Recommended for use in semiconductor fabrication equipment, E 2.5 turns, 2 circuits M 1 turn, 6 circuits liquid crystal manufacturing machines, testing instruments, food processing machines, medical F 2.5 turns, 3 circuits P See specifications. End deflector method instruments, machine tools, and automobile manufacturing equipment. By adding LUBSEAL to G 3.5 turns, 1 circuit Q See specifications. End cap method R 3.5 turns, 2 circuits Not listed above (including ball Z Other compatible ball screws, the maintainance interval between grease applications can be greatly (5) Nut Type screw shafts sold separately) increased. Symbol Nut type (6) Flange Type S Single nut Symbol Flange type A, B, C, ■―Various―types―of―grease T Integral nut Refer to page A-7. KURODA also provides a wide range of grease which fulfills your requirements, including D Double nut (pin type) D, E, H E Double nut (spacer type) N No flange (e.g. square nut) clean room compliance, anti-fretting corrosion, extreme pressure, low temperature, and wide Other: shapes and dimensions not listed in the catalog F Flange double nut (spacer type) Z temperature range. For more information, please contact . Z Other (including ball screw shafts sold separately) (including ball screw shafts sold separately) (7) Ball Recirculation System (nut body shape) (8) Wiper Material (9) Thread Direction ■― ――Examples―of―other―custom―ball―screws―with―special―dimensions― Symbol Ball recirculation system Symbol Wiper material Symbol Description A Round type (tube method) P Plastic wiper R Right-hand thread and rating requirements T Protruded tube type (tube method) L Lip seal L Left-hand thread also provides custom ball ●―Example―of―custom―nut―dimensions U Inlaid tube type (tube method) F Felt wiper Other (including ball screw Z screws with dimensions or specifications K Square type (tube method) B Brush wiper shafts sold separately) which are not listed as standard products in D Deflector method N No wiper (10) Overall Screw Shaft Length (indicated the catalog. Screw shaft G Guide plate method S LUBSEALTM by a 4-digit number) E End cap method Other (including ball screw · The shaft length is indicated in the Various ball screws which require special Z P End deflector method shafts sold separately) metric system (unit: mm), rounded profiles and dimensions to accommodate down to the nearest whole number. (11) Shaft End Configuration (14) Axial Clearance right-handed and left-handed screws, leads in Symbol Description Product line Symbol Axial clearance imperial/US units (i.e. inches), hollow screw A Both ends unfinished Standard product line S 0 mm (preloaded) shafts, square nuts and others are available. B One end finished Standard product line F 0.005 mm or less Ball screw nut X Both ends finished Standard product line, order-made product line Ball screws which are configured with a H 0.010 mm or less D Both ends unfinished For ordering GY series screw shafts without screw shaft having a gear, spline, serration M 0.030 mm or less Y Both ends finished ball screw nuts Component or housing attachment L 0.200 mm or less or the like, or are capable of withstanding (12) Thread Length (indicated by a 4-digit number) Axial clearance for rolled ball screws (Refer heavy loads can also be made upon request. · The length is indicated in the metric system (unit: mm), rounded down to Y For more information, please contact the nearest whole number. to the specifications of the GY/GW series.) Z Other . (13) Accuracy Grade · The accuracy grade is indicated by C0, C1, C2, C3, C4, C5, and C7. Because accuracy grade C10 is 3-digits long, “CA” is used instead.
A-9 A-10 ■―Ordering―instructions―for―standard―precision―ball―screws ■―Ordering―instructions―for―rolled―ball―screws
Unfinished―shaft―ends Unfinished―shaft―ends ball screws ball screws
Overview of ■―GE,―GG,―FE,―or―FG―series―ball―screws ■―GY―series―ball―screws Overview of ● For screws without additional end machining [For ball screws with both a shaft and nut]
A-11 A-12 ■―Ordering―instructions―for―order-made―ball―screws ■― ――For―order-made―ball―screws―with―nut―specifications―and―design―listed―in― this catalog ball screws
Overview of Simply enter the overall screw shaft length, X (the symbol for finished shaft ends), thread length, accuracy grade, and axial clearance after the listed Model Number information.
■― ――For―order-made―ball―screws―with―a―custom―flange,―but―otherwise―listed―nut― Page specifications―and―design Enter GM/DM/FM followed by shaft diameter, lead, number of circuits, and nut type. Select the Features and specifications of standard precision applicable the flange type (either N for no flange or Z for flange types other than those listed). Enter the ball recirculation system, wiper material, thread direction, and finally overall screw ball screws ―――――――――――――――――――――― B- 2 shaft length, X (the symbol for finished shaft ends), thread length, accuracy grade, and axial Ordering instructions, size reference chart ――――― B- 3 clearance.
GZ/DZ/FZ - Z - Overall screw shaft length X Thread length - Accuracy grade Axial clearance 16 mm shaft diameter ―――――――――――――――― B- 86 to 89 Model Number 20 mm shaft diameter ―――――――――――――――― B- 90 to 113 ■―Ordering―instructions―for―customized―rolled―ball―screws 25 mm shaft diameter ―――――――――――――――― B-114 to 127 ■― ――For―rolled―ball―screws―with―specifications―and―design―other―than―the―those― 32 mm shaft diameter ―――――――――――――――― B-128 to 131 listed in this catalog Enter GT followed by shaft diameter, lead, number of circuits, and nut type. Enter Z for flange type. Enter the ball recirculation system, wiper material, thread direction, and finally overall screw shaft length, X (the symbol for finished shaft ends), thread length, accuracy grade, and axial clearance.
A-13 B-1 of ball screws Technical data Technical Technical data of ball screws
Page Lead accuracy――――――――――――――――――――――― F- 2 to 3 Mounting accuracy and tolerance――――――――――――― F- 4 to 7 Preload torque――――――――――――――――――――――― F- 8 Screw shaft design― ――――――――――――――――――― F- 9 to 12 Service life calculation――――――――――――――――――― F-13 to 14 Ball screw design suitability―――――――――――――――― F-15 to 20 Torque――――――――――――――――――――――――――― F-21 to 22 Guide for ball screw selection――――――――――――――― F-23 to 29 Ball screw ordering information―――――――――――――― F-30 to 31
F-1 ■―Cumulative―mean―lead―error―and―permissible―variation―values Technical data of ball screws ●―Accuracy―grades―C0-C5
Table―2――Cumulative―mean―lead―error―(±Ec) and permissible variation values (ec) (Unit: μm) Accuracy grade Effective C0 C1 C2 C3 C4 C5 Lead accuracy thread length (mm) ±EC eC ±EC eC ±EC eC ±EC eC ±EC eC ±EC eC of ball screws of ball screws Technical data Technical The lead accuracy of ball screws is defined by the following characteristics in accordance with Over Or less data Technical − 315 4 3.5 6 5 9 6 12 8 15 11 23 18 the JIS Standard. The permissible values are shown in Tables 2 and 3. 315 400 5 3.5 7 5 10 7 13 10 17 13 25 20 400 500 6 4 8 5 11 7 15 10 19 13 27 20 Effective thread length 500 630 6 4 9 6 12 9 16 12 20 16 30 23 ＋ Cumulative nominal lead 630 800 7 5 10 7 14 10 18 13 24 17 35 25 800 1000 8 6 11 8 16 11 21 15 28 19 40 27 0 1000 1250 9 6 13 9 18 12 24 16 32 21 46 30 Cumulative Cumulative 1250 1600 11 7 15 10 21 13 29 18 38 24 54 35 actual lead specified lead － 1600 2000 18 11 26 15 35 21 46 28 65 40 Cumulative C 2000 2500 22 13 31 18 41 24 54 32 77 46 mean lead 2500 3150 26 15 37 21 50 29 66 38 93 54 M 3150 4000 32 18 43 24 62 35 80 46 115 65 4000 5000 76 41 97 54 140 77 5000 6000 170 93 Ec Table 3 Permissible variation values (Unit: mm) Accuracy grade C0 C1 C2 C3 C4 C5
ec e300 Item e300 e2π e300 e2π e300 e2π e300 e2π e300 e2π e300 e2π One Permissible value 3.5 3 5 4 6 5 8 6 11 7 18 8 revolution e2π 300 2π rad ●―Accuracy―grades―C7―and―C10 Table 4 Permissible values for The cumulative lead error of C7 and C10 grade ball screws cumulative lead error (Unit: μm) ■―Terms―and―definitions is prescribed by the permissible value for the lead error of a Accuracy grade C7 C10 specified lead which had a length of 300 mm arbitrarily taken Cumulative lead error 0.05/300 0.21/300 Specified―lead cumulative actual lead. It is obtained by the within the effective thread length of Table 5 Accuracy grade and axial clearance In most cases, the lead is the same as the least-squares method or an approximation the screw shaft, in accordance with Axial clearance Nut Accuracy grade nominal lead, but there are instances in which similar to this method using the curve Symbol (mm) combination JIS Standard. C0 C1 C2 C3 C4 C5 C7 C10 the nominal designation is adjusted when the representing the cumulative actual lead S 0 Double nut ○ ○ ○ ○ ○ ○ − − ■―Accuracy ―― grade and axial S 0 ○ ○ ○ ○ ○ ○ − − application so requires. corresponding to the effective travel of a nut or F 0.005 or less − ○ ○ ○ ○ ○ − − (Example: Nominal lead 10 mm → Specified the effective thread length of the screw shaft. clearance H 0.010 or less Single nut − − − − ○ ○ ○ − lead 9.9995 mm) Cumulative―mean―lead―error―“Ec” Possible combinations of accuracy M 0.030 or less − − − − ○ ○ ○ − L 0.200 or less − − − − − − ○ ○ Cumulative―specified―lead―target―value―“C” A value obtained by subtracting the cumulative grade and axial clearance are shown * Integral Nuts have the same possible combinations of axial clearance and lead accuracy grade as Double Nuts. In cases in which expansion and contraction specified lead target value (C) from the in Table 5. * The above table is for ground ball screws only. For rolled ball screws in GY/GW series, refer to the pages describing rolled ball screws. of the screw due to temperature change cumulative mean lead (M). * For any combinations not listed above, consult KURODA. or influence from the external load can be Variation ■―Accuracy―grade―and―manufacturable―screw―shaft―length anticipated, a target value of cumulative lead The maximum difference of the cumulative When the slenderness ratio (shaft length against shaft diameter) is large, it is sometimes difficult determined by testing or technical experience actual lead contained between two lines to manufacture a ball screw with the desired accuracy. The following table shows the maximum should be established in advance. For drawn parallel to the cumulative mean lead. It length of screw shafts of each accuracy grade that can be reliably manufactured. When ball presetting procedures, see the cumulative is prescribed by ec, e300, e2π. screws exceeding the manufacturable range are required, consult KURODA. specified lead setting procedures on page ec : Variation for the effective travel of the nut Table 6 Accuracy grade and manufacturable screw shaft length (Unit: mm) F-20. or the effective thread length of the screw Accuracy Screw shaft diameter Cumulative actual lead shaft. grade 5 6 8 10 12 15 · 16 20 25 28 32 36 40 45 50 55 63 70·80·100·125 C0 90 160 240 340 420 500 800 1100 1200 1600 1800 2000 2000 2000 2000 2000 − Cumulative lead obtained by either continuous e300 : Variation for a length of 300 mm arbitrarily C1 120 180 280 400 500 600 900 1300 1500 1800 2000 2200 2300 2800 3000 3000 3000 measurement of an actual ball screw or by taken within the effective thread length of C2 120 180 280 400 500 600 1100 1600 1800 2200 2500 2800 3000 3600 4000 4500 4500 measurement of a section including the axial the screw shaft. C3 140 210 340 480 600 700 1400 1800 2000 2500 2800 3200 3600 4000 5000 5000 5000 C4 140 210 340 480 600 800 1400 1800 2000 2500 2800 3200 3600 4000 5000 5000 5000 center of the screw shaft. e2π : Variation for one revolution (2 π rad) made C5 140 210 340 655 900 1500 2000 2000 2200 2800 3100 3600 4100 4500 5000 5000 5000 Cumulative―mean―lead―“M” within the effective thread length of the C7 − − 340 655 900 1500 2000 2300 2600 3200 3600 4600 5000 5000 5000 5000 5000 A straight line representing the trend of screw shaft. C10 − − − − − 1500 2000 2300 2600 3600 4000 4600 5000 5000 5000 5000 5000 (Note) When the lead is larger than the nominal screw shaft diameter, C0 and C1 accuracy grades are not manufacturable.
F-2 F-3 Mounting accuracy and tolerance ■―Accuracy―of―the―nut―mounting―portion Tables 9, 10 and 11 show the perpendicularity of the flange mounting surface and the outer ■―Accuracy―of―each―part―of―the―screw―shaft diameter of the nut body (9), the radial runout of the outer diameter of the nut body (10), and the Tables 7 and 8 show the tolerance of the radial runout of the thread groove and mounting parallelism tolerance of the outer diameter of the nut body (11) when measured against the axial portions when measured against the axial line of the supported shaft end (7) and the center of the screw shaft. of ball screws of ball screws Technical data Technical perpendicularity of the outer face of the supported shaft end (8). data Technical
Table―9――――Perpendicularity―of―the―flange―mounting―surface―and―the―outer―diameter―of―the― A Table 11 A nut body when measured against the axial center of the screw shaft (Unit: μm) Outer diameter of the nut (mm) Perpendicularity tolerance (maximum) Over Or less C0 C1 C2 C3 C4 C5 Table 8 E-F Table 9 G − 20 5 6 7 8 9 10 Tables 12-17 G or E-F 20 32 5 6 7 8 9 10 Table 7 A Table 7 A 32 50 6 7 8 8 10 11 50 80 7 8 9 10 11 13 80 125 7 9 10 12 13 15 125 160 8 10 11 13 15 17 G 160 200 − 11 12 14 16 18 E A F 200 250 − 12 13 15 17 20 Table 7 E-F Table 10 A
Table 8 E-F Table 8 E-F Table 10 Radial runout of the outer diameter of the nut body (when cylindrical) when measured against the axial center of the screw shaft (Unit: μm) Figure 5 Mounting accuracy of the ball screw (Illustration) Outer diameter of the nut (mm) Runout tolerance (maximum) Over Or less C0 C1 C2 C3 C4 C5 Table 7 Radial runout of the thread groove and mounting portions when measured − 20 5 6 7 9 10 12 against the axial line of the supported shaft end (Unit: μm) 20 32 6 7 8 10 11 12 Nominal screw shaft diameter (mm) Runout tolerance (maximum) 32 50 7 8 10 12 13 15 Over Or less C0 C1 C2 C3 C4 C5 50 80 8 10 12 15 17 19 − 8 3 5 7 8 9 10 80 125 9 12 16 20 23 27 8 12 4 5 7 8 9 11 125 160 10 13 17 22 26 30 12 20 4 6 8 9 10 12 160 200 − 16 20 25 29 34 20 32 5 7 9 10 11 13 200 250 − 18 23 28 33 38 32 50 6 8 10 12 13 15 50 80 7 9 11 13 15 17 Table 11 Parallelism tolerance of the outer diameter of the nut body (when planar) when 80 125 − 10 12 15 17 20 measured against the axial center of the screw shaft (Unit: μm) (Note) As the measurement of nominal screw shaft diameter takes into account the influence of the screw shaft axial runout, Basic mounting length (mm) Parallelism tolerance (maximum) it is necessary to correct the measurements. Calculate the correction value by using the total runouts (tolerance) of the screw shaft axial runout shown in Tables 12 to 17 corresponding to the ratio of the overall screw shaft length to Over Or less C0 C1 C2 C3 C4 C5 the distance between the supporting point and the measuring point (L1 and L2) and add it to the tolerance shown in − 50 5 6 7 8 9 10 the above table. 50 100 7 8 9 10 11 13 100 200 − 10 11 13 15 17 Table 8 Perpendicularity of the outer face of the supported shaft end when measured against the axial line of the supported shaft end (Unit: μm) Nominal screw shaft diameter (mm) Perpendicularity tolerance (axial runout) (maximum) Over Or less C0 C1 C2 C3 C4 C5 − 8 2 3 3 4 4 5 8 12 2 3 3 4 4 5 12 20 2 3 3 4 4 5 20 32 2 3 3 4 4 5 32 50 2 3 3 4 5 5 50 80 3 4 4 5 6 7 80 125 − 4 5 6 7 8
F-4 F-5 ■―Total―runout―of―the―axial―center―of―the―screw―shaft Table 15 Total runout of the axial center of the screw shaft [C3] (Unit: mm) Nominal screw shaft diameter Over − 8 12 20 32 50 80 Tables 12 to 17 show the permissible values for total runout of the axial center of the screw shaft. Overall screw shaft length Or less 8 12 20 32 50 80 125 Over Or less Table 12 Total runout of the axial center of the screw shaft [C0] (Unit: mm) − 125 0.025 0.025 0.020 Nominal screw shaft diameter Over − 8 12 20 32 50 80 125 200 0.035 0.035 0.025 0.020
of ball screws Overall screw of ball screws Technical data Technical shaft length Or less 8 12 20 32 50 80 125 200 315 0.050 0.040 0.030 0.030 data Technical Over Or less 315 400 0.060 0.050 0.040 0.035 0.025 − 125 0.015 0.015 0.015 400 500 0.065 0.050 0.040 0.030 125 200 0.025 0.020 0.020 0.015 500 630 0.080 0.055 0.045 0.035 0.030 200 315 0.035 0.025 0.020 0.020 630 800 0.070 0.055 0.040 0.035 315 400 0.035 0.025 0.020 0.015 800 1000 0.095 0.065 0.050 0.040 0.030 400 500 0.045 0.035 0.025 0.020 1000 1250 0.120 0.085 0.060 0.045 0.035 500 630 0.050 0.040 0.030 0.020 0.015 1250 1600 0.160 0.110 0.075 0.055 0.040 630 800 0.050 0.035 0.025 0.020 1600 2000 0.140 0.095 0.070 0.050 800 1000 0.065 0.045 0.030 0.025 2000 2500 0.120 0.085 0.060 1000 1250 0.085 0.055 0.040 0.030 2500 3150 0.160 0.110 0.075 3150 4000 0.220 0.150 0.100 1250 1600 0.110 0.070 0.050 0.040 4000 5000 0.200 0.130 1600 2000 0.095 0.065 0.045
Table 16 Total runout of the axial center of the screw shaft [C4] (Unit: mm) Table 13 Total runout of the axial center of the screw shaft [C1] (Unit: mm) Nominal screw Nominal screw shaft diameter Over − 8 12 20 32 50 80 shaft diameter Over − 8 12 20 32 50 80 Overall screw Overall screw shaft length Or less 8 12 20 32 50 80 125 shaft length Or less 8 12 20 32 50 80 125 Over Or less Over Or less − 125 0.030 0.030 0.030 − 125 0.020 0.020 0.015 125 200 0.040 0.040 0.035 0.030 125 200 0.030 0.025 0.020 0.020 200 315 0.055 0.050 0.040 0.035 200 315 0.040 0.030 0.025 0.020 315 400 0.070 0.060 0.050 0.040 0.035 315 400 0.045 0.040 0.030 0.025 0.020 400 500 0.075 0.055 0.050 0.040 400 500 0.050 0.040 0.030 0.025 500 630 0.090 0.070 0.055 0.050 0.035 500 630 0.060 0.045 0.035 0.025 0.020 630 800 0.080 0.065 0.055 0.040 630 800 0.060 0.040 0.030 0.025 800 1000 0.100 0.070 0.060 0.050 0.035 800 1000 0.075 0.055 0.040 0.030 1000 1250 0.130 0.090 0.070 0.055 0.040 1000 1250 0.095 0.065 0.045 0.035 0.030 1250 1600 0.170 0.120 0.080 0.060 0.045 1250 1600 0.130 0.085 0.060 0.045 0.035 1600 2000 0.150 0.110 0.080 0.060 1600 2000 0.120 0.080 0.055 0.040 2000 2500 0.130 0.100 0.070 2000 2500 0.100 0.070 0.050 2500 3150 0.180 0.130 0.090 2500 3150 0.130 0.090 0.060 3150 4000 0.240 0.170 0.120 3150 4000 0.120 0.080 4000 5000 0.220 0.150
Table 14 Total runout of the axial center of the screw shaft [C2] (Unit: mm) Table 17 Total runout of the axial center of the screw shaft [C5] (Unit: mm) Nominal screw Nominal screw Over − 8 12 20 32 50 80 shaft diameter Over − 8 12 20 32 50 80 shaft diameter Overall screw Overall screw shaft length Or less 8 12 20 32 50 80 125 shaft length Or less 8 12 20 32 50 80 125 Over Or less Over Or less − 125 0.025 0.020 0.020 − 125 0.035 0.035 0.035 125 200 0.035 0.030 0.020 0.025 125 200 0.050 0.040 0.040 0.035 200 315 0.045 0.035 0.025 0.025 200 315 0.065 0.055 0.045 0.040 315 400 0.050 0.045 0.035 0.030 0.025 315 400 0.075 0.065 0.055 0.045 0.035 400 500 0.055 0.045 0.035 0.025 400 500 0.080 0.060 0.050 0.045 500 630 0.090 0.075 0.060 0.050 0.040 500 630 0.065 0.050 0.040 0.030 0.025 630 800 0.090 0.070 0.055 0.045 630 800 0.065 0.045 0.035 0.030 800 1000 0.120 0.085 0.065 0.050 0.045 800 1000 0.080 0.060 0.045 0.035 1000 1250 0.150 0.100 0.075 0.060 0.050 1000 1250 0.105 0.070 0.050 0.040 0.030 1250 1600 0.190 0.130 0.095 0.070 0.055 1250 1600 0.140 0.095 0.065 0.050 0.035 1600 2000 0.170 0.120 0.085 0.065 1600 2000 0.130 0.090 0.065 0.045 2000 2500 0.150 0.110 0.080 2000 2500 0.110 0.080 0.055 2500 3150 0.200 0.140 0.095 2500 3150 0.140 0.100 0.065 3150 4000 0.260 0.180 0.120 3150 4000 0.130 0.090 4000 5000 0.240 0.160 4000 5000 0.110 5000 6300 0.320 0.210
F-6 F-7 Preload torque Screw shaft design Starting torque ■―Mounting―and―supporting―methods―for―the―screw―shaft Negative actual torque variation Actual torque There are four basic methods of mounting a screw shaft as shown below. Since the method of Torque variation screw shaft support has a direct relationship to permissible axial load and permissible rotational of ball screws of ball screws
Technical data Technical Forward data Technical (+) speed at critical speed, sufficient consideration should be given, especially when the conditions (-) of use require high accuracy or demanding performance. Effective thread length torque torque Mounting method Application example Reference Mean actual (minimum)
Frictional Actual torque torque 0 Distance between supports Effective thread length (Critical speed: one end fixed and the other end supported) Supported torque Mean Fixed
Reference Fixed actual torque (maximum) (-) Actual torque ● Typical mounting Backward (+) Actual torque method Positive actual torque variation Figure 6 ● Medium to high speed Torque variation Characteristics of range Starting torque ● Medium accuracy to preload torque high accuracy ■―Terms―and―definitions Actual torque Preload Preload torque measurement of an actual ball Distance between loading points A way to reduce the backlash or to increase screw. (Buckling load: both ends fixed) the rigidity of ball screws. This is achieved by Mean actual torque Distance between supports loading oversized steel balls or by inducing An arithmetic mean of the maximum and (Critical speed: both ends fixed) Fixed Fixed tension between a pair of nuts which are minimum values of the actual torque Fixed forced in opposite axial directions. measured by running the nut back and forth Preload torque over the effective thread length. ● Medium speed ● High accuracy The torque required to continuously rotate the Actual torque variation screw shaft or nut of a preloaded ball screw A maximum variation of actual torque when no external load is applied. measured by running the nut back and forth Standard torque over the effective thread length. The value is Distance between loading points (Buckling load: both ends fixed) The target preload torque value. described as a plus (+) or minus (-) value to Distance between supports Torque variation value the mean actual torque. (Critical speed: one end fixed and the other end free) The deviation in preload torque from the Actual torque variation ratio Fixed Fixed target preload torque. The value is described A ratio of actual torque variation to mean Free as a plus (+) or minus (-) value to the actual torque. ● Low speed standard torque. ● Short shaft length Torque variation ratio ■―Measuring―conditions ● Medium accuracy A ratio of torque variation to the standard Rotational speed for measurement: 100 min-1 torque. Viscosity of lubricant: ISO VG100 Distance between loading points ■―Permissible―ratio―of―torque―variation (Buckling load: both ends fixed) Table 18 Permissible ratio of torque variation Distance between supports Effective thread length (mm) (Critical speed: one end fixed and the other end supported) Reference Supported Supported 4000 or less Fixed torque Slenderness ratio: 40 or less Slenderness ratio: 60 or less (N·cm) Accuracy grade Accuracy grade ● Low to medium Over Or less C0 C1 C2 C3 C4 C5 C0 C1 C2 C3 C4 C5 speed range 20 40 ±35% ±40% ±45% ±45% ±50% ±55% ±40% ±45% ±50% ±55% ±60% ±65% ● Low accuracy to 40 60 ±25 ±30 ±35 ±35 ±40 ±45 ±33 ±38 ±45 ±45 ±50 ±50 medium accuracy 60 100 ±20 ±25 ±30 ±30 ±35 ±35 ±25 ±30 ±35 ±35 ±40 ±40 100 250 ±15 ±20 ±25 ±25 ±30 ±30 ±20 ±25 ±30 ±30 ±35 ±35 250 630 ±10 ±15 ±20 ±20 ±25 ±25 ±15 ±20 ±25 ±25 ±30 ±30 630 1000 − − ±15 ±15 ±20 ±20 − − ±20 ±20 ±25 ±25 Distance between loading points (Note) Slenderness ratio is the value obtained by dividing the thread length (mm) of the screw shaft by the nominal screw shaft diameter (mm). (Buckling load: one end fixed and the other end supported)
F-8 F-9 ■―Permissible―axial―load ●― ――Permissible―axial―load―against―buckling― ●― ――Buckling― load― calculated― by― Euler's― ■―Permissible―rotational―speed A diagram of permissible axial load for load: P Formula: Pk The permissible rotational speed of ball 2 selecting the minimum shaft diameter for the P = αPk (N) ……………………………… (1) nπ EI screws is expressed by a DmN value which Pk = 2 (N) ………………………… (2) axial load is shown below. Where, ℓ indicates the upper limit of the operating
(1) The diagonal line indicates the permissible Pk : Buckling load (N) speed of recirculating balls in the nut and the of ball screws of ball screws Technical data Technical Where, data Technical axial load determined by the buckling of α : Safety factor (α = 0.5) critical speed of the rotary shaft. Pk : Load at which buckling starts (N) the screw shaft. Please refer to the scale It may be necessary to set the safety ℓ : Distance between loading points (mm) The optimum shaft diameters for various that corresponds to the correct method of factor at a larger value according to the E : Young’s modulus (2.06 X 105 N/mm2) rotational speeds are shown in Figure 8. screw shaft support. degree of safety required. I : Minimum secondary moment of the (1) The diagonal line indicates the rotational (2) The lines parallel to the line representing screw shaft root cross section (mm4) speed determined by the critical speed. the distance between supports indicate Generally, the buckling load of a long column Please refer to the scale that corresponds to can be calculated by Euler's Formula. π 4 the permissible tensile/compression load. I = d the correct method of screw shaft support. Please refer to the Supported-Supported However, when the slenderness ratio/k (k: 64 (2) The lines parallel to to the line representing scale. Second cross section) is 90 or less, use the d : Screw shaft root diameter (mm) the distance between supports indicate (3) The lines perpendicular to the line Rankine Forumla or the Tetmajer Formula. Refer to dimension tables. the limit of the permissible rotational speed representing the distance between n : Coefficient to be determined by the obtained from the DmN value. Please supports indicate the screw shaft lengths supporting method of the ball screw refer to the scale that corresponds to the that can be manufactured by standard Supported-Supported n = 1 “Supported-Supported” method of screw processes as KURODA. (See Table 6 on Fixed-Supported n = 2 shaft support. page F-3.) Fixed-Fixed n = 4 (3) The lines perpendicular to the line Fixed-Free n = 0.25 representing the distance between supports indicate the screw shaft lengths that can be manufactured by standard 106 Screw shaft diameter (mm) 2 3 1.5 8 Example:― Selection― of― the― processes as KURODA. (See Table 6 on ø80 1.5 6 shaft diameter page F-3.) 2 106 5 105 1.5 8 4 ø63 How to determine an ●―DmN―value 8 6 3 appropriate shaft diameter 106 5 ø50 ◦ GR, DR, GE/GG, GP, DP, and HG series 6 when the screw shaft is 5 8 4 2 DmN ≤ 70000 ………………………… (3) 4 6 3 1.5 ø40 supported with the “Fixed- ◦ GY and GW series 3 5 Supported” method and a 4 2 105 ø32 DmN ≤ 50000 ………………………… (3) 2 8 compression load of 24000N 3 1.5 ◦ FR and FE/FG series 1.5 6 ø25 (maximum axial load) is applied 2 105 5 DmN ≤ 135000 104 1.5 8 4 to a distance of 2000 mm 8 ø20 Where, 6 3 5 between loading points: 6 10 5 Dm: Screw shaft diameter (mm) + A (mm) ø15 1. Find out the intersecting -1 5 8 4 2 N : Maximum rotational speed (min )
Permissible axial load (N) 4 6 3 1.5 point where the permissible 24000N N (max) ≤ 5000 3 5 axial compression load 4 2 104 Ball diameter A Ball diameter A 2 8 ø10 on the scale of “Fixed- 3 1.5 0.8000 0.24 3.1750 0.80 1.5 6 Supported” is 24000N and 2 104 5 1.0000 0.30 3.9688 0.80 3 10 1.5 8 4 the distance between loading 1.2000 0.30 4.7625 1.00 8 6 3 points is 2000 mm as shown 1.5875 0.30 6.3500 1.80 104 6 5 2.0000 0.40 7.1438 2.00 5 8 4 2 by a thick line in Figure 7. 2.3812 0.60 7.9375 2.00 4 6 3 1.5 2. Then, select a shaft 5 3 2.7780 0.60 9.5250 2.40 4 2 103 diameter of 40 mm or more, 102 1.5 23456789103 1.5 234567 Fixed-Fixed Supported-Supported represented by one of the Note) Consult KURODA if the number of Fixed-Free Fixed-Supported Distance between loading points (mm) Screw shaft supporting method diagonal lines located above revolutions on your application exceeds Figure 7 Diagram of permissible axial load the intersecting point. the DmN value above or N (max) 5000.
F-10 F-11 Resonance phenomenon arising from the ●―Critical―speed:―Nc Service life calculation ●―Basic―static―load―rating:―C0 2 3 rotational speed of a ball screw and the The basic static load rating (C0) represents 60λ EI × 10 −1 Nc = fa 2 (min ) ……… (4) 2πℓ γA characteristic frequency of the screw shaft ■―Service―life―of―ball―screws an axial load at at certain amount of static is caused by the unbalance of deflection by load in which the sum of the permanent Where, The service life of a ball screw is defined as ℓ : Distance between supports (mm) the empty weight of the shaft at the distance a total number of revolutions with which the deformities of the steel balls and the thread of ball screws of ball screws Technical data Technical fa : Safety factor (0.8) “ℓ” between supports of the rotation system screw can perform proper operation without groove surface equal to 0.01 percent of the data Technical E : Young’s modulus (2.06 X 105 N/mm2) and the critical speed corresponding to causing operation-affecting wear (flaking) to steel ball diameter. I : Minimum secondary moment of the the characteristic frequency increases the the thread groove and/or balls. The flaking In most cases, the permanent deformities will 4 screw shaft root cross section (mm ) amplitude of the vibration. is caused by metal fatigue due to constant not cause operational issues. However, when
π 4 When the ball screw is used, the nut stress. The service life of a ball screw is high accuracy or very smooth operation are I = d 64 serves as a mobile bearing, and therefore, determined by the basic dynamic load rating. required, it is recommended that a ball screw d : Screw shaft root diameter (mm) the distance “ℓ” between supports always having a C0 value notably larger than the Refer to dimension tables. changes and the shaft deflection changes static load be selected. For basic static load -6 3 ■―Service―life γ : Specific gravity (7.8 X 10 kg/mm ) as well. Since the critical speed shown The service life of a ball screw is calculated ratings, refer to the dimension tables listed in A : Sectional area of the screw shaft root 2 in Formula (4) is inconstant, consider the by the following formula: this calatog. diameter (mm ) permissible rotational speed to assure safety. 6 3 10 C π 2 A = d Lh = (hours) …………… (5) ●―Basic―dynamic―load―rating:―C 4 60Nm ( Pmfw ) Example― 1:― Determining― the― The basic dynamic load rating (C) is an axial permissible rotational speed Where, λ : Coefficient to be determined by the How to determine permissible load in which when a certain number of Lh : Service life (hours) method of ball screw support rotational speed when the screw ball screws are run for 1 million revolutions Supported-Supported λ = π shaft is supported with the “Fixed- C : Basic dynamic load rating (N) (106 revolutions) and 90% of that group of Fixed-Supported λ = 3.927 Supported” method, the screw shaft diameter is 20 mm and the distance Refer to dimension tables. Fixed-Fixed λ = 4.730 ball screws does not experience operation- between supports is 1500 mm: Pm: Average axial load (N) Fixed-Free λ = 1.875 1. The vertical dotted line in Figure 8 -1 affecting wear (flaking). For basic dynamic Nm: Average rotational speed (mm ) shows that the distance between load ratings, refer to the dimension tables supports is 1500 mm. Find the point fw : Load factor (coefficient by operating Screw shaft diameter (mm) of intersection with the diagonal listed in this calatog. 3 condition) ø10 line representing the critical speed of a screw shaft with a diameter of Smooth operation without concussive 2 5 ø15 20 mm. ●― ――Average―axial―load―“Pm”―and―average― 1.5 4 ø20 impact fw = 1.0 to 1.2 2. The scale for the “Supported- rotational―speed―“Nm” 5 3 ø25 Normal operation fw = 1.2 to 1.5 ) 3 Supported” method of screw shaft -1 10 4 To select a suitable ball screw, determine ø32 8 5 support indicates that, in this case, Operation associated with concussive 3 2 ø40 the permissible rotational speed is the following values. It may be difficult to 6 4 -1 1.5 ø50 1076 min . impact or vibration fw = 1.5 to 2.0 5 3 accurately predict these operating conditions, 2 ø63 4 The basic dynamic load rating that satisfies 3 1.5 10 ø80 Example―2:―How―to―determine―an― but it is advisable to gather accurate 3 2 the intended service life is obtained from the 8 ø100 appropriate shaft diameter values because the service life is inversely 103 1.5 6 How to determine an appropriate following formula: 2 1070 8 min-1 5 shaft diameter that can meet a proportional to the load value multiplied by a 103 1 1.5 4 maximum rotational speed “1000 60LhNm 3 6 -1 power of three. Accurate values will result in a
Permissible rotational speed (mm 8 C = 6 PmfW (N) 5 min ” when the screw shaft is 2 3 ( 10 ) 10 greater selection of suitable ball screws. 6 4 supported with the “Fixed-Fixed” 8 5 method and the distance between (t1 + t2 + t3 = 100%) 3 2 If a ball screw is selected using overly 6 4 supports is 2000 mm: 1.5 Axial load Rotational speed Operating time ratio 5 1. The thick vertical line in Figure 8 conservative service life values, the size and 3 2 −1 2 4 10 shows that the distance between P1N (maximum) N1 min t1 % 1.5 cost of the resulting ball screw may increase 2 supports is 2000 mm. Find the −1 3 8 P2N (normal) N2 min t2 % point of intersection with the unnecessarily. Some case examples of 1.5 102 −1 6 horizontal line representing the P3N (minimum) N3 min t3 % 2 8 5 standard life requirements are given below for 102 permissible rotational speed “1000 1.5 6 4 min-1”on scale for the “Fixed-Fixed” reference. 8 5 3 method of screw shaft support. 10 Machine tools 20000 hours 6 4 2. Shaft diameters represented by the 8 5 2 Industrial machinery 10000 hours 3 102 1.5 23456789103 1.5 2345 lines above the intersecting point Fixed-Fixed Supported-Supported have a permissible rotational speed Automated control equipment 15000 hours Fixed-Free Fixed-Supported Distance between supports (mm) -1 Screw shaft supporting method of “1000 min ” or more. In this case, a shaft diameter of 25 mm is Measuring instruments 15000 hours Figure 8 Diagram of the permissible rotational speed found to be sufficient.
F-12 F-13 In the case of machine tools, the maximum 3 3 3 1 P1 N1t1 + P2 N2t2 + P3 N3t3 3 Ball screw design suitability load (P1) is a “load applied at the time of Pm = (N) …(6) ( N1t1 + N2t2 + N3t3 ) heaviest cutting”. The normal load (P2) is a In order to work out an optimum design for machines, it is necessary to examine the rigidity of N1t1 + N2t2 + N3t3 -1 “load applied during general cutting”. The Nm = (min )……………(7) the feed screw system, the positioning accuracy and the driving torque in due consideration of t1 + t2 + t3 minimum load (P3) is a “load applied at the the required function, performance and cost. of ball screws of ball screws Technical data Technical When the difference between the maximum data Technical time of rapid feeding of the cutting tool before axial load (P1) and the minimum axial load starting cutting and at the time of quick ■ Rigidity of the feed screw system 1. When the supporting method is “Fixed-Free” (P3) is small, or when the load exhibits return after completion of cutting”. Once the To improve the positioning accuracy and linear change, an approximate value can be Fixed Free above-mentioned values are determined, responsiveness of precision machines and calculated from the following formula: the average axial load (Pm) and the average equipment when they are controlled, it is
rotational speed (Nm) can be obtained from 2P1 + P3 necessary to take into consideration the Pm ≈ (N)………………………(8) ℓ the following formulas: 3 rigidity of each component of the feed screw system. The rigidity (K) of the feed screw 4Pℓ 3 δℓ = 2 ×10 (µm) ………………… (17) system is calculated by the following formula: Eπd ■―Hardness―and―service―life P Where, When special materials for corrosion load rating (C’) and the basic static load K = (N/µm) ……………………… (14) P : Axial load (N) δ 5 2 resistance, etc. are used, the thread groove rating (C0’) are calculated with the following E : Young’s modulus (2.06 X 10 N/mm ) Where, cannot be hardened to HRC58-62. In such formulas, assuming that the respective d : Screw shaft root diameter (mm) P : Axial load applied to the feed screw cases, the basic dynamic load rating and hardness factors are (fH) and (fH’). system (N) ℓ : Distance between loading points (mm) the basic static load rating decrease in δ : Axial elastic deformation of the feed C′ = fHC (N) ……………………… (10) proportion to the decreased hardness. When screw system (μm) 2. When the supporting method is “Fixed-Fixed” C0′ = fH′C0 (N) ……………………… (11) the hardness value is low, the basic dynamic The relationship between the rigidity of the Fixed Fixed feed screw system and that of each component Table―19――Hardness―factors is as follows: Hardness HRC 58 or above 56 54 52 50 40 30 20 10 1 1 1 1 1 = + + + ………… (15) ℓℓ′ fH 1.0 0.88 0.72 0.58 0.47 0.27 0.16 0.10 0.07 K Kℓ Kn Kb Kh L fH′ 1.0 0.83 0.61 0.45 0.32 0.14 0.07 0.03 0.02 Where, 4Pℓℓ′ 3 Kℓ : Rigidity of the screw shaft to tension and δℓ = 2 ×10 (µm) ……………… (18) compression Eπd L
■―Temperature―and―service―life Kn : Rigidity of the nut Where, When an operating a ball screw made of adversely affect operation. When the ball Kb : Rigidity of the support bearing P : Axial load (N) 5 2 standard material (See Table 1 on page screw operates at a temperature at 100°C Kh : Rigidity of the nut mounting portion and E : Young’s modulus (2.06 X 10 N/mm ) A-6) at a constant temperature of 100°C or or above, the basic dynamic load rating the bearing mounting portion d : Screw shaft root diameter (mm)
above or when operating it at a extremely (C’’) and the basic static load rating (C0’’) ℓ, ℓʹ: Distance between loading points (mm) high temperature for a short period of time, are calculated by the following formulas, ●― ――Tension―and―compression―strength―of―the― L : Distance between supports (mm) the composition of the material changes; screw shaft: Kℓ assuming that the respective temperature The maximum value is obtained from thus, the basic dynamic load rating and factors are (ft) and (ft’). P L Kℓ = (N/µm) ……………………… (16) Formula (18) when ℓ = ℓʹ = . the basic static load rating decrease as δℓ 2 C″ = ftC (N) ……………………… (12) the temperature increases. However, Where, PL 3 δℓ = 2 ×10 C0″ = ft′C0 (N) ……………………… (13) temperatures of up to 100°C will not P : Axial load (N) ( Eπd )
δℓ : Amount of expansion or contraction of Therefore, the maximum expansion and Table 20 Temperature factors the screw shaft (μm) contraction of the screw shaft supported Temperature (°C) 100 or below 125 150 175 200 When an external axial load is applied to the with the both ends fixed becomes 1/4 of ft 1.0 0.95 0.90 0.85 0.75 screw shaft, the axial expansion and contraction those using the “Fixed-Free” method of ft′ 1.0 0.93 0.85 0.78 0.65 is calculated by the following formulas. The screw shaft support. axial expansion and contraction come out directly as the backlash of the ball screw.
F-14 F-15 ●―Rigidity―of―the―nut:―Kn Rigidity of the preloaded nut: Knw The load applied to Nuts A and B is: As shown in equation (23), the preload Rigidity of the single nut (non- The dimension table for each product series PA = PL + P0 - P0′ = P0 + PL0 effect is about 3 times as much as the PB = PL - P0′ = PL0 preload amount. Generally, therefore, the preloaded): Kns gives theoretical rigidity (KNW) obtained from When a ball screw receives an axial load, the amount of elastic deformation that will Therefore, an amount of (P0’) of the external preload amount is set at 1/3 of the maximum the steel balls and the thread groove will be occur when a preload of 1/15 of the basic load (P0) is offset because the deformation axial load. On the other hand, taking into of ball screws of ball screws Technical data Technical data Technical deformed. The relationship between the axial dynamic load rating (C) is applied to the nut of Nut B decreases. As a result, the elastic consideration the life and efficiency, the
load (P) and the axial elastic deformation (δns) and an axial load of about 3 times or less of deformation of Nut A is reduced. This effect preload amount is usually set at 1/20 to 1/10 is calculated by the following formula: the preload is applied. These values are of will continue until (δnwB) is zeroed, namely of the basic dynamic load rating.
2 1 practical use, because they were calculated until the elastic deformation caused by the 2.6 Q −2 3 δns = ×10 K (µm) …… (19) on the basis of the results of the rigidity test external load becomes (δnw0) and the preload Classification―of―preload sin α ( Db ) including the nut rigidity test. Rigidity (Knw) applied to Nut B is completely released. Light Normal Medium Heavy Where, preload preload preload preload corresponding to an arbitrary preload can be Deformation δnw1 1 1 1 1 1 1 α : Contact angle of steel balls with the of Nut B to to obtained from the following formula: Preload 20 C or 20 15 15 10 10 C or thread groove (45°) less C C more 1 PL Deformationof Nut A Db: Steel ball diameter (mm) 3 C: Basic dynamic load rating (N) Knw = KNW 1 (N/µm) …………… (22) Px K : Accuracy and structure coefficient ( 15C ) P0 (1.4-1.6) Where, P0′ Axial load P → Elastic―displacement―curve―of―the― PL Q : Load per steel ball (N) PL : Preload (N) PL0 preloaded nut C : Basic dynamic load rating (N) P Figure 11 shows elastic displacement Q = Deformation δ Z sin α δnw0 δnw0 curves of a single nut (non-preloaded) and Backlash―and―preload Nut A Nut B a preloaded nut. Where an axial load (PX), P : Axial load (N) The backlash of a ball screw is the sum of the which is three times as large as the preload Z : Number of steel balls axial clearance and the elastic deformation Figure 10 Preload diagram (PL), is applied, the elastic displacement Theoretical rigidity (KNS) obtained from the caused by the axial load at the contact point of the preloaded nut is just one half of the amount of elastic deformation when an axial of the steel balls with the thread groove. The Proper ball screw preload The axial elastic deformation (δnw0) is elastic displacement of the single nut (non- load equivalent to 30% of the basic dynamic axial elastic deformation can be reduced to a proportional to a value obtained by raising preloaded). load rating (C) is shown in the dimension great extent by setting a proper preload and the axial load (P) to two-thirds power table for each of the product series. thus, the rigidity can be increased.
according to the Hertz’s law of point contact. nw
Rigidity (KnS) corresponding to an arbitrary δ 2δnw0 Double nut preload effect Therefore, deformation caused by preloading Single nut axial load (P) is calculated by the following Parallel is: (non-preloaded) formula: Nut B Fixed pin Nut A 2 3 δnw0 = C·PL a 1 δnw0 c P 3 PL PL Deformation caused by an external load KnS = KNS (N/µm) …………… (20) Preloaded nut (0.3C) when the preload applied to one nut is
Where, completely released is: Elastic deformation 2 b 3 C : Basic dynamic load rating (N) 2δnw0 = C·Px PL Px ≈ 3PL P : Axial load (N) From the above two equations, Axial load P PL0 P0+PL0 2 PX 2δnw0 (δnS) in Formula (19) is calculated by the 3 = = 2 Figure―11――Elastic―deformation―curve―of―the―nut P0 ( PL ) δnw0 following formula using the rigidity (KNS) of the single nut and the basic dynamic load rating (C). Therefore, the released preload is: Figure 9 Double nut preload effect 1 2 (0.3C) 3 P 3 δnS = (µm) ……………… (21) In Figures 9 and 10, Nuts A and B undergo PX = 2.8PL ≈ 3PL …………………… (23) KNS an elastic deformation of (δnw0) by preload Where, Where, (PL) respectively. When external load (P0) is Px : Released preload (N) KNS: Theoretical rigidity of the single nut (N/μm) applied to Nut A, the elastic deformation of Refer to the content for each series. (External axial load when preload applied Nuts A and B is: to one nut returns to zero) C : Basic dynamic load rating (N) δnwA = δnw0 + δnw1 PL P : Axial load (N) : Preload (N) δnwB = δnw0 - δnw1
F-16 F-17 Double nut preloading methods ● Preloaded with spacer ●―Rigidity―of―the―support―bearing:―Kb ●― ――Rigidity―of―the―nut―mounting―portion―
Preloading is to be applied, in general, to In this method, preload is adjusted by the The rigidity of a bearing to which preload and the bearing mounting portion: Kh
two nuts in tension (tension preloading) or in thickness of a spacer inserted between (PL) is applied is calculated with the following In designing these portions, pay due regard compression (compression preloading) using the two nuts. Both tension preloading and formulas: to the thickness and the distance from the bolts. compression preloading are available. mounting surface to the ball screw shaft of ball screws of ball screws Technical data Technical ● Rigidity of the ball bearing data Technical KURODA’s ball screws use tension center, so that the rigidity of the nut bracket preloading unless otherwise specified. 2.83PL and the bearing box may be improved. When Kb = (N/µm) ………………… (24) δb Direction of tension Direction of tension the distortion due to tension of the set bolt Fixed pin Where, is not negligible, use the mounting method Nut A Nut B PL : Preload (N) shown in Figure 17 on page F-18. δb : Axial elastic deformation to preload (μm) Axial elastic deformation of the angular ball ●―Torsional―rigidity―of―the―screw―shaft Screw shaft Figure 16 Preloaded with spacer (I) bearing is: Direction of tension Direction of tension 2 1 The screw shaft is twisted around the axial 2 Q 3 Spacer δb = (µm) ……………… (25) line by the torsional moment (driving torque), sin α Db Nut A Nut B ( ) P resulting in rotational strain. The torsional Q = Z sin α deformation can be calculated as the axial deformation of the ball screw by the following Screw shaft Axial elastic deformation of the thrust ball bearing is: formulas: Figure 12 Tension preloading Q2 1 3 L Direction of compression Direction of compression δb = 2.4 (µm) ………………… (26) Figure 17 Preloaded with spacer (II) Db δT = ℓθ …………………………… (29) Spacer ( ) 2π P Nut A Nut B Q = 32T Integral nut preloading method Z θ = 4 …………………………… (30) πd G In this method, a slightly offset lead at the Where, Where, Screw shaft center of a nut generates preload in the nut. δb : Axial elastic deformation (μm) δT : Axial deformation caused by torsion (cm) Direction of tensionDirection of tension α : Contact angle Figure 13 Compression preloading Db: Steel ball diameter (mm) ℓ : Distance between working points (cm) ℓ + Δℓ Q : Load per steel ball (N) θ : Angle of torsion (rad/cm) ● Preloaded with pin (standard method of Z : Number of steel balls L : Lead of the ball screw (cm) KURODA) P : Axial load (N) T : Torsional moment (N·cm) This is the simplest and most effective Screw shaft d : Root diameter of the screw shaft (cm) ℓ ● Rigidity of the roller bearing tension preloading method. The required G : Modulus of rigidity (83 X 105 N/cm2) preload is attained and kept by inserting a pin Figure 18 Integral nut preloading method 2.16PL Kb = (N/µm) ……………… (27) If the angle of torsion for the driving shaft is between the two nuts. δb excessively large, defections on the parts Single nut preloading method Where, of the driving mechanism may be caused In this method, a nut is preloaded by putting PL : Preload (N) and result in torsional vibration of the shaft oversized steel balls between the thread δb : Axial elastic deformation to preload (μm) groove of the screw shaft and that of the nut. Axial elastic deformation of the tapered system. For ordinary driving shafts, the angle roller bearing is: of torsion due to the maximum operating Nut 0.9 0.6 Q torsional moment should be set within 4.36 X δb = · 0.8 (µm) ……………… (28) sin α ℓ 10 -5 (rad/cm). P Figure 14 Preloaded with pin (I) Screw shaft Q = Z sin α Figure 19 Single nut preloading method Where,
δb : Axial elastic deformation (μm) α : Contact angle ℓ Q : Load per roller (N) Figure 20 Z : Number of rollers P : Axial load (N) Figure 15 Preloaded with pin (II) ℓ : Effective contact length of the roller (mm)
F-18 F-19 ■―Notes―for―positioning―accuracy Driving torque ●―Friction―torque―caused―by―preload This paragraph deals with how to select the accuracy grade, how to determine the cumulative A torque produced by preloading. As the specified lead, and how to take effective measures against thermal strain, which will exert a Frictional characteristics of the ball screw external load increases, the preload applied great influence upon the positioning accuracy. and selection of the drive motor to the preloaded nut is gradually released and consequently, the friction torque caused of ball screws of ball screws Technical data Technical ●― ――Selection―guide―for―the―accuracy― ●― ――Determining―the―cumulative―specified― ■―Friction―and―efficiency by preload is also reduced. data Technical The efficiency “η” of a ball screw obtained grade classified according to the lead Without load: type of the machine In most cases, the lead is the same as by the analysis of a mechanical model of the PLL Select the accuracy grade of the ball screw the nominal lead, but there are instances screw can be calculated as follows, assuming TP = K (N·cm) …………………… (36) 2π suited for the required positioning accuracy in which the nominal designation is that the coefficient of friction = μ and the 1 − 2 from Tables 2 and 3 on page F-3. KURODA adjusted to account for expansion due to screw lead angle = β. K = 0.05 (tanβ) recommends that you select the accuracy temperature increase during operation or ● When converting the rotational force into Where, grade in accordance with the following table. the expansion or contraction of the screw the axial force (normal operation): PL : Preload (N) shaft due to the external load. In such cases, Table―21――――Examples―of―the―accuracy―grade― 1 - μ tan β L : Lead of the ball screw (cm) inform KURODA of the target value of the η = …………………… (32) of the ball screw recommendable 1 + μ / tan β K : Coefficient of internal friction cumulative lead. The typical target values of according to the type of the machine ● When converting the axial force into the β : Lead angle Accuracy the cumulative lead classified according to Type of the machine rotational force (reverse operation): -1 L grade the type of the machine are shown in Table β ≈ tan 1 - μ / tan β (πD) Machining centers X, Y C1 to C3 22 below. To correct the expansion, a tensile η′ = …………………… (33) Milling machines Z C2 to C5 load may sometimes be applied to the screw 1 + μ tan β D : Screw shaft diameter (cm) X C1 to C3 Lathes shaft when mounting. Z C3 to C5 X C0 to C2 Table 22 Target values of the cumulative ■―Load―torque ■―Selection―of―the―drive―motor NC machine Grinding machines The load torque (constant-speed driving Select a drive motor which meets the tools Z C1 to C3 lead classified according to the Electric discharge X, Y C1 to C3 machine type (Unit: mm) torque) required for designing a driving unit following conditions. machines Z C2 to C5 Target value of the (motor, etc.) can be calculated as follows. 1. The motor should be able to sufficiently Punching machines C3 to C5 Machine type Axis cumulative lead bear the load torque applied to its output Wood working machines (per meter) C5 to C7 ●―Normal―operation shaft. (NC routers) X -0.02 to -0.05 NC lathes When converting the rotational force into the 2. The motor should be able to start and Cartesian coordinates type Z -0.02 to -0.03 C1 to C5 (assembly) Machining centers X, Y -0.03 to -0.04 axial force stop at the required pulse speed when the Industrial Vertical revolute type moment of inertia is applied to its output robots C2 to C5 PL (assembly) ●― ――Measures―to―be―taken―for―thermal― T = (N·cm) …………………… (34) 2πη shaft. SCARA type (assembly) C3 to C5 displacement 3. The required acceleration constant and Exposure system Where, C0 to C1 As the ball screw is constructed so that its Drawing system T : Load torque (N·cm) deceleration constant can be obtained rolling motion involves a slight sliding motion, Etching equipment P : Axial external load (N) when the moment of inertia is applied to C3 to C7 Semiconductor Ion implanting equipment it inevitably suffers a thermal strain due to L : Lead of the ball screw (cm) the output shaft of the motor. manufacturing Wire bonders rising temperature. The temperature increase C1 to C2 η : Efficiency of the ball screw (0.9) equipment Die bonders is closely related to operating conditions. The Table F Workpiece Wafer probers C0 to C2 W expansion of the thermal displacement can Gear J2 Electrical parts charging ●―Reverse―operation C2 to C7 Z2 apparatus, Insert machines be calculated by the following formula: When converting the axial force into the Ball screw J3 Pinion J1 Electronic color separating C0 to C2 Δℓ = ρtℓ (mm) ………………………… (31) rotational force Z1 Motor Printing apparatus Where, equipment Electronic composing 2πT C1 to C3 P = (N) ………………………… (35) Figure 21 machines Δℓ : Axial thermal displacement (mm) η′L Color graphic printers C1 to C3 ρ : Coefficient of thermal expansion Business -6 -1 Where, XY plotters (11.7 X 10 °C ) equipment C1 to C3 P : Axial external load (N) Auto drawing machines t : Temperature increase of the screw shaft T : Load torque (N·cm) (°C) L : Lead of the ball screw (cm) ℓ : Effective thread length (mm) η’ : Efficiency of the ball screw (0.9)
F-20 F-21 2 ●― ――Constant― torque― applied― to― the― J1 : Moment of inertia of the pinion (kg·cm ) 2 Guide for ball screw selection output shaft of a motor J2 : Moment of inertia of the gear (kg·cm ) When a ball screw is selected, a number of factors are examined from various points of view on A torque required for driving at a constant J3 : Moment of inertia of the ball screw speed against an external load (kg·cm2) the basis of the above-mentioned basic subjects by a process of trial and error. Therefore, the procedure cannot be categorically determined. An example of general procedures and main J4 : Moment of inertia of the motor rotor of ball screws of ball screws
Technical data Technical PL (3PL−P) Z1 data Technical 2 T1 = + TP (kg·cm ) subjects for examination regarding each item and reference pages are mentioned below: (2πη 3PL ) Z2 (N·cm) … (37) J5 : Moment of inertia of the moving object (kg·cm2) Selection Subjects to be Where, P ≤ 3PL 2 procedures examined J6 : Moment of inertia of the coupling (kg·cm ) T1 : Driving torque at a constant speed (N·cm) M : Mass of the table and work (kg) L : Lead of the ball screw (cm) P : Axial external load (N) ● Work and table mass ● Maximum feed rate ● Velocity diagram ● External load Moment of inertia of the cylinders such as P = F + µMg Operating ● Maximum stroke ● Mounting condition (horizontal and vertical) the ball screw and the gear F : Anti-thrust repulsive force by cutting force conditions ● Duty (operation) cycle ● Operation coefficient ● Mounting and supporting method (Calculation of J1-J4 and J6) (N) ● Expected life ● Positioning accuracy ● Environmental conditions ● Lubrication
πγ 4 2 M : Weight of the table and work (kg) J = D ℓ (kg·cm ) ……………… (40) (Selection of the lead) 32 μ : Coefficient of friction of the sliding surface ● Maximum feed rate ● Maximum rotational speed of the motor ● Positioning resolution 2 Where, g : Acceleration of gravity (9.8 m/s ) Lead ● List of nominal screw shaft diameters and leads (B-3, C-3, D-3) L : Lead of the ball screw (cm) D : Outside diameter of the cylinder (cm) ● Torque (F-21) η : Mechanical efficiency of the motor ℓ : Length of the cylinder (cm) (Designing and life calculation of the nut) including the ball screw and the gear γ : Specific gravity of the material -3 3 ● Average axial load and average rotational speed (F-13) TP : Friction torque caused by preload (N·cm) γ = 7.8 X 10 (kg/cm ) ● Service life estimation (F-13) Refer to Formula (36). 2 Number of L 2 circuits J5 = M (kg·cm ) ……………… (41) ● Permissible rotational speed (DmN value) (F-11) P : Preload (N) (2π) ● Dimensions Z1 : Number of teeth of the pinion (Designing of the screw shaft) Z2 : Number of teeth of the gear ●― ――Total―torque―applied―to―the―output― ● Screw shaft supporting method (F-9) shaft of a motor ● Permissible buckling load (F-10) Screw shaft ●― ――Acceleration―torque―applied―to―the― The total torque can be calculated by adding ● Permissible rotational speed (critical speed) (F-12) output shaft of a motor the value of Formula (38) to that of Formula ● Accuracy grade and manufacturable shaft length (F-3) A torque required for accelerative driving (37). (Design for accuracy) against an external load TM = T1 + T2 (N·cm) ………………… (42) ● Lead accuracy and axial clearance (F-3) Accuracy grade • 2πN -2 Where, ● Countermeasures against thermal change (F-20) T2 = JMω = JM × × 10 and rigidity 60t TM: Total torque applied to the output shaft of ● Rigidity of feed screw system (F-15) (N·cm) … (38) the motor (N·cm) 2 Z1 T1 : Driving torque at a constant speed JM = J1 + J4 + (J2 + J3 + J5 + J6) (N·cm) (Others) ( Z2 ) Lubrication and 2 ● Lubrication and operating cautions (A-3, A-4) (kg·cm ) … (39) T2 : Driving torque at the time of acceleration dust prevention Where, (N·cm) T2 : Driving torque at the time of acceleration After provisionally selecting a motor, check (N·m) • the motor for the following three items. The Selection of ω : Angular acceleration of the motor shaft motor you select should satisfactorily meet For the model number of ball screws, see A-10. 2 ball screws (rad/s ) the respective values. N : Rotational speed of the motor shaft (1) Effective torque value -1 (min ) (2) Acceleration constant t : Acceleration time (s) (3) Over-load characteristics and tolerance to JM : Moment of inertia applied to the motor overheat of the motor at the time of repetitive 2 (kg·cm ) starting and stopping
F-22 F-23 ■―Example―of―ball―screw―selection calculated in the same manner as in the case Rigidity of the nut (Knw) of lead 6 is: Rigidity to an arbitrary preload amount
●―Machine―tool Pm = 2600 (N) assuming that 1/3 of the -1
F-24 F-25 ■―Example―of―ball―screw―selection Transformation formula (5) shown on page on the repeated positioning accuracy ±0.01. F-13 is used assuming that the operation
●―X-axis―of―Cartesian―robot―(horizontal―position) coefficient fw = 1.2, as shown below. 5. Result of ball screw and support 1 unit selection
distance between loading points ℓ1 = 820. 1. Lead (L) Operating time (s) during one cycle of each The following formula can be obtained by According to the maximum rotational speed pattern Formulas (1) and (2) on pages F-10 and F-11: and the rapid traverse speed of the motor, Operation pattern (a) (b) (c) Total operating time Pk = 7220 (N) the lead can be selected as follows: Operating time 0.6 0.84 0.6 2.04 This fully satisfies the operating condition. Vmax × 60 Load conditions at the time of lead 20 L ≥ = 20 (mm) Assuming that the distance between Nmax Operation pattern (a) (b) (c) supports ℓ2 = 790, the critical speed can be Axial load 343N 10N 324N 2.―Nut―design Rotational speed 1500 min−1 3000 min−1 1500 min−1 obtained by Formula (4) (Fixed-Supported) Examination of the necessary basic dynamic Operating time ratio 29.4% 41.2% 29.4% on page F-12 as follows: -1 Nc = 3024 (min ) load rating and the permissible rotational Calculating the axial average load (Pm) and This satisfies the operating condition. speed (DmN value) the average rotational speed (Nm) from the Calculation of the axial load in each pattern load conditions (Formulas (6) and (7) on of operations: page F-14) results in the following formulas: 4. Accuracy Examination of the accuracy grade and the (a) At the time of acceleration Pm = 249 (N) -1 axial clearance Vmax -3 2 Nm = 2118 (min ) Acceleration (α) = × 10 = 6.67 (m/s ) t Calculation of the necessary basic dynamic The accuracy grade that can satisfy the positioning accuracy of ±0.1/750 mm is Axial load (Pa) = (Mα + μMg) = 343 (N) load rating (C) 2 determined, from the permissible value (g: Gravitational acceleration 9.8 m/s ) The net operation life (Lh0) excluding (b) At the time of a constant speed downtime based on the expected life is of the lead accuracy (page F-3), to be C5 (cumulative mean lead error ±Ec = 0.035 and Axial load (Pb) = μMg = 10 (N) calculated as follows: (c) At the time of deceleration 2.04 variation ec = 0.025). Lh0 = 30000 = 14927 (hours) Axial clearance is set to 0.005 or less based Axial load (Pc) = (Mα - μMg) = 324 (N) ( 4.1 )
F-26 F-27 ■―Example―of―ball―screw―selection shown on page F-13 is used assuming that the operation coefficient fw = 1.5, as shown ●―Elevator―(vertical―position) below. 1
● Mass of the work and the table 2 ( 10 ) ℓ of ball screws of ball screws Technical data Technical data Technical M = 100 (kg) A suitable nut size can be selected from rolled ball screw GY series (page D-72 and D-73) ● Maximum stroke Smax = 1300 (mm) 1
Work ℓ based on the repeat accuracy 0.5 as follows: ● Rapid traverse speed Vmax = 15000 (mm/min) ● Acceleration/deceleration constant Outside diameter 25, lead 10, and 2.5 turns with 2 circuits t = 0.5 (S) When looking for a DmN value (Formula (3) ● Repeat accuracy 0.5 (mm) on page F-11) as the permissible rotational Distance between supports Table speed, DmN = 26.8 X 1500 = 40200 is found
● Expected life Lh = 20000 (hours) (Critical speed: Fixed-Supported) ● Friction factor of the linear guide as against the permissible DmN ≤ 50000,
(Buckling load: Fixed-Fixed) showing that it satisfies the permissible μ = 0.02 Distance between loading points - 1 value. Proceed with the following examination ● Drive motor Nmax = 1500 (min ) ● Duty cycle model diagram based on this size. 1300 (stroke) V mm/min 15000 mm/min 3. Screw shaft design (Upward) (Downward) Examination of the overall screw shaft length (ℓ) and permissible axial load (Pk) 0.5 4.7 0.55 0.5 4.7 0.5 5 s ℓ = Maximum stroke + nut length + safety 21.4 (1 cycle) stroke + size of both shaft ends To obtain permissible axial load, examine 1. Lead (L) Operating time (s) during one cycle of each the buckling load, assuming that distance
According to the maximum rotational speed pattern (s) between load working points ℓ1 = 1440. and the rapid traverse speed of the motor, Operation pattern (a) (b) (c) Total operating time The following formula can be obtained by the lead can be selected as follows: Operating time 1 9.4 1 11.4 Formulas (1) and (2) (Fixed-Fixed) on pages
Vmax Load conditions at the time of lead 10 F-10 and F-11: L ≥ = 10 Nmax Operation pattern (a) (b) (c) Pk = 16290 (N) Axial load 1030N 980N 930N This satisfies the operating condition. Rotational speed 750 min−1 1500 min−1 750 min−1 2.―Nut―design Assuming that distance between supports δ2 Examination of the necessary basic dynamic Operating time ratio 8.8 % 82.4 % 8.8 % = 1420, the following formula can be obtained
load rating and the permissible rotational Calculating the axial average load (Pm) and by Formula (4) (Fixed-Supported) on page
speed (DmN value) the average rotational speed (Nm) from the F-12: -1 Calculation of the axial load in each pattern load conditions (Formulas (6) and (7) on Nc = 1520 (min ) of operations: page F-14) results in the following formulas: This satisfies the operating condition.
(a) At the time of upward acceleration and Pm = 980 (N) -1 downward deceleration Nm = 1368 (min ) 4. Result of Ball Screw Selection
Vmax - 3 2 Calculation of the necessary basic dynamic Provided that additional machining of rolled Acceleration (α) = × 10 = 0.5 (m/s ) t·60 load rating (C) ball screw GY series is performed, the
Axial load (Pa) = (Mα + Mg) = 1030 (N) The net operation life (Lh0) excluding following model number is selected from (g: Gravitational acceleration 9.8 m/s2) downtime based on the expected life is page D-72 and D-73: (b) At the time of a constant speed calculated as follows: GY2510ES-HULR-2000A
Axial load (Pb) = Mg = 980 (N) 11.4 Lh0 = Lh = 10654 (hours) (c) At the time of upward deceleration and ( 21.4 ) downward acceleration As the operation accompanied by vibration
Axial load (Pc) = (Mg - Mα) = 930 (N) is anticipated, transformation formula (5)
F-28 F-29 Ballscrew specification data sheet Ballscrew specification data sheet (Sample) Date Contact personnel Date Contact personnel Company name Company name XYZ Industries, Co., Ltd. Department TEL / FAX Department TEL / FAX of ball screws of ball screws Technical data Technical Conditions of use Conditions of use data Technical Mass (weight) of table Maximum table speed mm/sec Mass (weight) of table 50kg Maximum table speed 250 mm/sec Moving conditions Shaft rotation Nut rotation Lubrication Grease Oil Moving conditions Shaft rotation Nut rotation Lubrication Grease Oil Mount method Horizontal Vertical Others (Description: ) Mount method Horizontal Vertical Others (Description: ) Mount/Support method Fixed-support Fixed-fixed Fixed-free Support-support Mount/Support method Fixed-support Fixed-fixed Fixed-free Support-support Oscillation No Yes (stroke mm) Oscillation No Yes (stroke mm) Environmental conditions Temp. ( °C) Clean room Vacuum Others ( ) Environmental conditions Temp. ( 25 °C) Clean room Vacuum Others ( ) Expected life Ex.: 8 hours/day, 240 days/year, 5 years Expected life 20000 hours (including downtime) Ex.: 8 hours/day, 240 days/year, 5 years Ballscrew specifications Ballscrew specifications Screw shaft diameter Thread direction Axial clearance Thread length Screw shaft diameter Thread direction Axial clearance Thread length Lead Nuber of circuits Accuracy grade Overall length Lead Nuber of circuits Accuracy grade Overall length Nut type Single nut Double nut Integral nut Nut type Single nut Double nut Integral nut Operating conditions Operating conditions Case ACase B Case ACase B (when axial load and table speed can be classified into several patterns, such as (when only the speed changes, such as for transfer application, and when largely (when axial load and table speed can be classified into several patterns, such as (when only the speed changes, such as for transfer application, and when largely when using a pressing device) impacted by inertial force) when using a pressing device) impacted by inertial force) Table speed Table speed No. of patterns Axial load Table speed Usage time No. of patterns Axial load Table speed Usage time mm/sec 250 mm/sec 1 1 2 Stroke 2 Stroke 3 mm Downtime 3 300 mm Downtime 10 4 sec 4 sec 5 5 Acceleration time Deceleration time Acceleration time Deceleration time 6 6 secsec 0.3 secs0.3 ec Others Others Type of slide guide Rolling (model number: ) Sliding Type of slide guide Rolling (model number: ) Sliding Name of motor Name of motor Quantity of screw shafts used Ex.: One per head, Four per table Quantity of screw shafts used One per X-axis Ex.: One per head, Four per table Change control No Yes Change control No Yes
Memo (Please draw a configuration diagram, etc.) Memo (Please draw a configuration diagram, etc.) Stroke Ceiling 300 mm Support Support Ball screw Servo motor Total (Lead 5) 50 kg
Guide Floor Request for Request for selection of ball screws Request for calculation of ball screw life Request for Request for selection of ball screws Request for calculation of ball screw life KURODA Contact personnel: KURODA Contact personnel:
F-30 F-31 Reference data Reference data
Page Table of standard tolerance grades and limit deviations for holes―――――――――――――――――――――――― Appendix-2 Table of standard tolerance grades and limit deviations for shafts― ―――――――――――――――――――――― Appendix-3 Dimensions of C-shaped snap rings―――――――――― Appendix-4 Dimensions of parallel keys and key grooves――――― Appendix-5 Hardness conversion chart― ――――――――――――― Appendix-6 Dimensions of the counterbore and internal thread for the hexagon-headed bolt― ―――――――――――――― Appendix-7
Appendix-1
- 6 - 8 - 6 - 9 - 8 - 9 + 6 - 11 - 11 - 16 - 20 - 16 - 24 - 20 - 29 - 24 - 29 - 28 - 68 - 28 - 68 - 33 - 79 - 33 - 79 - 17 - 42 - 17 - 42 - 24 - 59 - 24 - 59 - 21 - 51 - 21 - 51 - 14 - 35 - 14 - 35 + 29 + 18 + 24 + 15 + 20 + 12 + 12 + 51 + 32 + 68 + 43 + 79 + 50 + 35 + 22 + 42 + 26 + 59 + 37 - 6 - 9 - 6 - 9 - 12 - 17 - 12 - 12 - 21 - 17 - 15 - 12 - 26 - 21 - 15 - 26 - 36 - 61 - 36 - 61 - 41 - 70 - 41 - 70 - 21 - 37 - 21 - 37 - 30 - 52 - 30 - 52 - 26 - 45 - 26 - 45 - 18 - 31 - 18 - 31 + 8 + 4 n6 p6 + 23 + 12 + 19 + 10 + 16 + 10 + 39 + 20 + 52 + 27 + 60 + 31 + 28 + 15 + 33 + 17 + 45 + 23
- 4 - 4 - 4 - 4 - 4 - 5 - 4 - 5 - 7 - 8 - 8 - 9 - 9 - 7 - 14 - 16 - 14 - 19 - 16 - 23 - 19 - 23 - 12 - 52 - 12 - 52 - 14 - 60 - 14 - 60 - 33 - 33 - 10 - 45 - 10 - 45 - 39 - 39 - 28 - 28 + 7 + 6 + 4 + 8 + 2 + 8 + 9 + 11 + 18 + 15 + 12 + 30 + 40 + 15 + 46 + 17 + 21 + 25 + 35 + 13
Reference data Reference data Unit: μm = 0.001 mm Unit: μm = 0.001 mm - 4 - 5 - 4 - 7 - 5 - 9 - 7 - 9 11 - - 11 - 10 - 13 - 10 - 16 - 13 - 20 - 16 - 20 - 20 - 45 - 20 - 45 - 22 - 51 - 22 - 51 - 12 - 24 - 28 - 12 - 28 - 16 - 38 - 16 - 38 - 14 - 33 - 14 - 33 - 24 + 7 + 6 + 9 + 4 + 6 + 2 + 8 + 9 + 11 + 15 + 12 + 24 + 33 + 15 + 37 + 17 + 17 + 20 + 28 + 13 m5 m6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 - 2 - 2 0 - 12 - 12 - 12 - 15 - 12 - 18 - 15 - 18 - 40 - 40 - 46 - 46 - 21 - 21 - 25 - 25 - 35 - 35 - 30 - 30 + 1 + 1 + 9 + 1 + 6 + 2 + 3 + 4 + 2 + 2 + 3 + 12 + 10 + 21 + 28 + 33 + 15 + 18 + 25 - 2 - 8 - 1 - 2 - 9 - 8 - 3 - 1 - 9 - 4 - 3 - 4 - 8 - 8 - 8 - 8 - 4 - 4 - 4 - 4 - 6 - 6 - 5 - 5
- 12 - 15 - 12 - 15 - 33 - 33 - 37 - 37 - 17 - 17 - 20 - 20 - 28 - 28 - 24 - 24 0 + 9 + 7 + 6 + 4 + 1 + 1 + 1 + 2 + 3 + 4 + 2 + 2 + 3 + 11 + 15 + 21 + 24 + 13 + 18 0 0 0 - 9 - 9 + 5 + 6 + 5 + 6 + 3 + 3 + 6 + 6 + 7 + 7 + 9 + 9 - 10 - 12 - 10 - 12 - 10 - 10 - 28 - 28 - 33 - 33 - 15 - 15 - 18 - 18 - 25 - 25 - 21 - 21 + 12 + 12 + 13 + 13 + 10 + 10 ± 20 ± 23 0 0 0 ± 12.5 ± 10.5 ± 17.5 - 7 - 9 - 7 - 9 - 6 - 6 - 6 - 6 + 2 + 2 + 2 + 2 + 2 + 2 + 4 + 4 + 5 + 5 + 2 + 2 + 3 + 3 + 4 + 4 + 4 + 4 - 11 - 11 - 21 - 21 - 24 - 24 - 13 - 13 - 18 - 18 - 15 - 15 ± 11 ± 12.5 ± 14.5 ± 20 ± 20 ± 23 ± 23 ± 10.5 ± 10.5 ± 12.5 ± 12.5 ± 17.5 ± 17.5 ± 4 ± 5.5 ± 9 ± 3 ± 4.5 ± 7.5 ± 2 ± 3 ± 5 ± 9 ± 10 ± 4.5 ± 6.5 ± 2.5 ± 4 ± 6 ± 6.5 ± 9.5 ± 15 ± 7.5 ± 5.5 ± 8 ± 8 ± 8 ± 3 ± 5 ± 4± 3 ± 6 ± 5 ± 4 ± 6 ± 11 ± 11 ± 4.5 ± 7.5 ± 5.5± 4.5 ± 7.5 ± 9 ± 5.5± 6.5 ± 9 ± 6.5 ± 9.5 ± 15 ± 9.5 ± 15 ± 12.5 ± 12.5 ± 14.5 ± 14.5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 - 52 - 43 - 30 - 36 - 25 - 74 - 87 - 62 - 115 - 100 + 40 + 48 + 40 + 58 + 48 + 70 + 58 + 70 + 84 + 84 + 100 + 100 + 160 + 160 + 185 + 185 + 120 + 120 + 140 + 140
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 - 33 - 27 - 18 - 22 - 14 - 46 - 54 - 63 - 72 - 39 + 62 + 62 + 25 + 30 + 25 + 36 + 30 + 43 + 36 + 43 + 52 + 52 + 74 + 74 + 87 + 87 + 115 + 115 + 115 + 100 + 100
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 - 21 - 18 - 12 - 15 - 10 - 30 - 35 - 40 - 46 - 25 + 39 + 39 + 14 + 18 + 14 + 22 + 18 + 22 + 27 + 27 + 33 + 33 + 46 + 46 + 54 + 54 + 63 + 63
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 - 8 - 9 - 6 - 11 - 13 - 19 - 22 - 25 - 29 - 16 + 25 + 25 + 10 + 12 + 10 + 15 + 12 + 15 + 18 + 18 + 21 + 21 + 30 + 30 + 35 + 35 + 40 + 40
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 + 6 + 8 + 6 + 9 + 8 + 9 - 9 - 8 - 5 - 6 - 4 11 + 11 + 11 + 11 + 16 + 16 + 13 + 13 + 19 + 19 + 22 + 22 + 25 + 25 - - 13 - 15 - 18 - 20 + 29 0 + 46 0 + 72 0 + 29 0 + 46 0 + 72 0 Tolerance grades for holes Tolerance Tolerance grades for holes Tolerance Tolerance grades for shafts Tolerance + 9 + 9 + 2 + 4 + 2 + 5 + 4 + 6 + 5 + 6 + 7 + 7 - 7 - 6 - 4 - 5 - 2 - 8 - 9 + 34 + 34 + 12 + 16 + 12 + 20 + 16 + 24 + 20 + 24 + 28 + 28 + 40 + 10 + 40 + 47 + 10 + 12 + 47 + 54 + 12 + 14 + 54 + 14 + 61 + 15 + 61 + 15 - 20 - 17 - 12 - 14 - 10 - 29 - 12 - 34 - 14 - 39 - 15 - 44 - 25 + 9 + 9 + 8 + 2 + 8 + 4 + 2 + 5 + 4 + 6 + 5 + 6 + 7 + 7 + 25 + 25 + 12 + 14 + 12 + 17 + 14 + 17 + 20 + 20 + 29 + 10 + 29 + 34 + 10 + 12 + 34 + 39 + 12 + 14 + 39 + 14 + 44 + 15 + 44 + 15 - 7 - 9 - 6 - 4 - 9 - 5 - 2 - 6 - 11 - 16 - 20 - 14 - 10 - 23 - 12 - 27 - 14 - 32 - 15 - 35 + 6 + 6 + 64 + 25 + 64 + 25 + 20 + 28 + 20 + 10 + 35 + 28 + 13 + 10 + 43 + 35 + 16 + 13 + 43 + 53 + 16 + 20 + 53 + 20 + 76 + 30 + 76 + 90 + 30 + 36 + 90 + 36 + 46 + 46 + 50 + 50 - 6 + 106 + 106 + 122 + 122 - 20 - 53 - 25 - 64 - 16 - 43 - 10 - 28 - 13 - 35 - 20 - 30 - 76 - 36 - 90 - 43 - 50 - 106 - 122 + 6 + 6 + 50 + 25 + 50 + 25 + 16 + 22 + 16 + 10 + 28 + 22 + 13 + 10 + 34 + 28 + 16 + 13 + 34 + 41 + 16 + 20 + 41 + 20 + 60 + 30 + 60 + 71 + 30 + 36 + 71 + 83 + 36 + 43 + 83 + 43 + 96 + 50 + 96 + 50 - 6 - 20 - 41 - 25 - 50 - 16 - 34 - 10 - 22 - 13 - 28 - 16 - 30 - 60 - 36 - 71 - 43 - 83 - 50 - 96 + 6 + 6 + 41 + 25 + 41 + 25 + 12 + 18 + 12 + 10 + 22 + 18 + 13 + 10 + 27 + 22 + 16 + 13 + 27 + 33 + 16 + 20 + 33 + 20 + 49 + 30 + 49 + 58 + 30 + 36 + 58 + 68 + 36 + 43 + 68 + 43 + 79 + 50 + 79 + 50 - 6 - 20 - 33 - 25 - 41 - 16 - 27 - 10 - 18 - 13 - 22 - 12 - 30 - 49 - 36 - 58 - 43 - 68 - 50 - 79 + 50 + 50 + 39 + 14 + 50 + 39 + 20 + 14 + 61 + 50 + 25 + 20 + 75 + 61 + 32 + 25 + 75 + 92 + 32 + 40 + 92 + 40 + 60 + 60 + 72 + 72 + 85 + 85 + 112 + 112 + 134 + 134 + 159 + 159 + 185 + 185 + 215 + 100 + 215 + 100 - 40 - 92 - 50 - 32 - 75 - 20 - 50 - 25 - 61 - 14 - 39 - 60 - 72 - 85 - 112 - 134 - 159 - 185 - 100 - 215 + 89 + 50 + 89 + 50 + 28 + 14 + 38 + 28 + 20 + 14 + 47 + 38 + 25 + 20 + 59 + 47 + 32 + 25 + 59 + 73 + 32 + 40 + 73 + 40 + 60 + 60 + 72 + 72 + 85 + 85 + 106 + 106 + 126 + 126 + 148 + 148 + 172 + 100 + 172 + 100 - 40 - 73 - 50 - 89 - 32 - 59 - 20 - 38 - 25 - 47 - 14 - 28 - 60 - 72 - 85 - 106 - 126 - 148 - 100 - 172 + 75 + 50 + 75 + 50 + 24 + 14 + 32 + 24 + 20 + 14 + 40 + 32 + 25 + 20 + 50 + 40 + 32 + 25 + 50 + 61 + 32 + 40 + 61 + 40 + 90 + 60 + 90 + 60 + 72 + 72 + 85 + 85 + 107 + 107 + 125 + 125 + 146 + 100 + 146 + 100 - 40 - 61 - 50 - 75 - 32 - 50 - 20 - 32 - 25 - 40 - 14 - 24 - 60 - 90 - 72 - 85 - 107 - 125 - 100 - 146 + 80 + 80 + 60 + 20 + 78 + 60 + 30 + 20 + 98 + 78 + 40 + 30 + 98 + 50 + 40 + 50 + 65 + 65 + 180 + 180 + 120 + 120 + 149 + 149 + 220 + 100 + 220 + 260 + 100 + 120 + 260 + 305 + 120 + 145 + 305 + 145 + 355 + 170 + 355 + 170 - 65 - 80 - 50 - 93 - 30 - 60 - 40 - 76 - 20 - 45 - 117 - 142 - 100 - 174 - 120 - 207 - 145 - 245 - 170 - 285 + 80 + 80 + 45 + 20 + 60 + 45 + 30 + 20 + 76 + 60 + 40 + 30 + 93 + 76 + 50 + 40 + 93 + 50 + 65 + 65 + 117 + 117 + 142 + 142 + 174 + 100 + 174 + 207 + 100 + 120 + 207 + 245 + 120 + 145 + 245 + 145 + 285 + 170 + 285 + 170 - 65 - 98 - 80 - 50 - 77 - 30 - 48 - 40 - 62 - 20 - 34 d8 d9 e7 e8 e9 f6 f7 f8 g5 g6 h5 h6 h7 h8 h9 js5 js6 js7 k5 k6 + 80 + 80 + 34 + 20 + 48 + 34 + 30 + 20 + 62 + 48 + 40 + 30 + 77 + 62 + 50 + 40 + 77 + 98 + 50 + 65 + 98 + 65 - 119 - 100 - 146 - 120 - 174 - 145 - 208 - 170 - 242 + 119 + 119 + 146 + 100 + 146 + 174 + 100 + 120 + 174 + 208 + 120 + 145 + 208 + 145 + 242 + 170 + 242 + 170 - 3 - 3 - 3 6 10 3 6 3 6 63 10 6 6 10 4050 50 65 1418 18 24 24 30 30 40 6580 80 100 10 14 1014 14 1018 18 1424 14 24 1830 18 30 2440 24 40 3050 30 50 4065 40 65 5080 50 80 65 100 65 80 80 100 100120 120 140 140 160 160 180 180 200 200 225 225 250 100120 120 100140 140 120 120 160 160 140 140 180 180 160 160 200 200 180 180 225 225 200 200 250 225 225 250 Over Or less D8 D9 D10 E7 E8 E9 F6 F7 F8 G6 G7 H6 H7 H8 H9 H10 JS6 JS7 K6 K7 M6 M7 N6 N7 P6 P7 Over Or less D8 D9 D10 E7 E8 E9 F6 F7 F8 G6 G7 H6 H7 H8 H9 H10 JS6 JS7 K6 K7 M6 M7 N6 N7 P6 P7 Over Or less dimensions (mm) dimensions (mm) dimensions (mm) Range of standard Range of standard Range of standard Table 1: Standard tolerance grades and limit deviations for holes JIS B 0401-2:1998 (ISO 286-2:1988) Table 2: Standard tolerance grades and limit deviations for shafts JIS B 0401-2:1998 (ISO 286-2:1988) Table
Appendix-2 Appendix-3 Table 3: C-Shaped Snap Rings JIS B 2804:2001 Table 4: Dimensions of parallel keys and key grooves JIS B 1301:1996
m Key Key groove S = tolerance of b × 1/2 b 1 Cross section of key groove S1 r 2
1.6 2
d4 d2 d1 t b Reference data Reference data d5 b2 h c 1 25 d3 ℓ t
t 25 1.6 d S2 b1 6.3 d0 a n h
Position the holes at the neb of the snap ring (diameter d0) 6.3 “d5” represents the maximum circumferential so that they protrude out of the snap ring groove and are diameter when the ring is snapped onto the shaft. S = tolerance of h × 1/2 visible above the external diameter of the shaft end. 2
Unit: mm Unit: mm (1) Snap ring Corresponding shaft (for reference purpose only) Nominal size Dimensions of key Dimensions of key groove Ref. d1 f b a d0 d2 m n
b h Standard groove 1 2 d3 d1
Standard Standard Standard Standard 2 1 2 Tolerance Tolerance Approximate Approximate Minimum Tolerance Tolerance Minimum b1 b2 dimensions dimensions dimensions dimensions Nominal 2 key size (1)
0 C ℓ and b r1 and r2 b × h 1 shaft 10 9.3 1.6 3.0 17 10 9.6 and t 1
± 0.15 1.2 - 0.09 t Standard Standard of b diameter d (N9) (Js9) Tolerance of Tolerance Standard Standard Tolerance
11 10.2 1.8 3.1 18 11 10.5 Corresponding dimensions dimensions dimensions of t dimensions of t Tolerance Tolerance Tolerance Tolerance (h9) Tolerance 12 11.1 1.8 3.2 1.5 19 12 11.5 Standard dimensions 1 ± 0.05 1.15 2 × 2 2 0 2 0 6 to 20 2 - 0.004 1.2 1.0 6 to 8 14 12.9 2.0 3.4 22 14 13.4 ± 0.0125 15 13.8 2.1 3.5 23 15 14.3 3 × 3 3 - 0.025 3 - 0.025 0.16 to 0.25 6 to 36 3 - 0.029 0.08 to 0.16 1.8 1.4 8 to 10 0 + 0.1 16 14.7 ± 0.18 2.2 3.6 1.7 24 16 15.2 - 0.11 4 × 4 4 4 8 to 45 4 2.5 1.8 10 to 12 0 0 0 0 5 × 5 5 5 h9 10 to 56 5 ± 0.0150 3.0 2.3 12 to 17 17 15.7 2.2 3.7 25 17 16.2 - 0.030 - 0.030 - 0.030 18 16.5 2.6 3.8 26 18 17.0 6 × 6 6 6 14 to 70 6 3.5 2.8 17 to 22 0 0.25 to 0.40 0.16 to 0.25 19 17.5 2.7 3.8 27 19 18.0 1.5 (7 × 7) 7 7 16 to 80 7 4.0 3.0 20 to 25 0 - 0.030 0 20 18.5 2.7 3.9 28 20 19.0 ± 0.0180 22 20.5 1.2 2.7 4.1 31 22 21.0 1.35 8 × 7 8 - 0.036 7 18 to 90 8 - 0.036 4.0 3.3 22 to 30 24 22.2 3.1 4.2 33 24 22.9 10 × 8 10 8 22 to 110 10 5.0 3.3 30 to 38 2 0 25 23.2 ± 0.06 3.1 4.3 34 25 23.9 12 × 8 12 8 0 28 to 140 12 5.0 3.3 38 to 44 ± 0.20 - 0.21 14 × 9 14 9 - 0.090 36 to 160 14 5.5 3.8 44 to 50 26 24.2 3.1 4.4 35 26 24.9 0 0.40 to 0.60 0 0.25 to 0.40 28 25.9 3.1 4.6 38 28 26.6 (15 × 10) 15 10 40 to 180 15 ± 0.0215 5.0 5.0 50 to 55 - 0.043 - 0.043 + 0.2 + 0.14 16 × 10 16 10 45 to 180 16 6.0 4.3 50 to 58 30 27.9 (2) 3.5 4.8 40 30 28.6 (2) 1.6 1.75 0 0 32 29.6 3.5 5.0 43 32 30.3 18 × 11 18 11 50 to 200 18 7.0 4.4 58 to 65 35 32.2 4.0 5.4 46 35 33.0 20 × 12 20 12 56 to 220 20 7.5 4.9 65 to 75 22 × 14 22 14 63 to 250 22 9.0 5.4 75 to 85 36 33.2 ± 0.25 4.0 5.4 47 36 34.0 0 0 0 (24 × 16) 24 16 70 to 280 24 ± 0.0260 8.0 8.0 80 to 90 38 35.2 4.5 5.6 50 38 36.0 - 0.052 - 0.110 0.60 to 0.80 - 0.052 0.40 to 0.60 0 40 37.0 4.5 5.8 53 40 38.0 25 × 14 25 14 70 to 280 25 9.0 5.4 85 to 95 1.8 - 0.25 1.95 42 38.5 4.5 6.2 55 42 39.5 28 × 16 28 16 80 to 320 28 10.0 6.4 95 to 110 45 41.5 ± 0.40 4.8 6.3 58 45 42.5 32 × 18 32 18 90 to 360 32 11.0 7.4 110 to 130 ± 0.07 2 h11 48 44.5 4.8 6.5 62 48 45.5 (35 × 22) 35 22 100 to 400 35 11.0 11.0 125 to 140 2.5 50 45.8 5.0 6.7 64 50 47.0 36 × 20 36 20 - 36 12.0 8.4 130 to 150 (38 × 24) 38 0 24 - 38 0 12.0 12.0 140 to 160 55 50.8 5.0 7.0 70 55 52.0 0 ± 0.0310 2 2.2 40 × 22 40 - 0.062 22 1.00 to 1.20 - 40 - 0.062 0.70 to 1.00 13.0 9.4 150 to 170 56 51.8 5.0 7.0 71 56 53.0 - 0.130 60 55.8 5.5 7.2 75 60 57.0 (42 × 26) 42 26 - 42 13.0 13.0 160 to 180 0 45 × 25 45 25 - 45 15.0 10.4 170 to 200 65 60.8 6.4 7.4 81 65 62.0 + 0.3 ± 0.45 - 0.30 50 × 28 50 28 - 50 17.0 11.4 200 to 230 70 65.5 6.4 7.8 86 70 67.0 0 2.5 ± 0.08 2.7 2.5 75 70.5 7.0 7.9 92 75 72.0 56 × 32 56 32 - 56 20.0 12.4 230 to 260 63 × 32 63 0 32 1.60 to 2.00 - 63 0 1.20 to 1.60 20.0 12.4 260 to 290 80 74.5 7.4 8.2 97 80 76.5 ± 0.0370 - 0.074 - 0.074 85 79.5 8.0 8.4 103 85 81.5 70 × 36 70 36 0 - 70 22.0 14.4 290 to 330 80 × 40 80 40 - 0.160 - 80 25.0 15.4 330 to 380 90 84.5 8.0 8.7 108 90 86.5 0 3 3.2 3 90 × 45 90 0 45 2.50 to 3.00 - 90 0 2.00 to 2.50 28.0 17.4 380 to 440 95 89.5 8.6 9.1 114 95 91.5 - 0.35 ± 0.0435 + 0.18 - 0.087 - 0.087 100 94.5 ± 0.09 9.0 9.5 3 119 100 96.5 100 × 50 100 50 - 100 31.0 19.5 440 to 500 ± 0.55 0 105 98.0 9.5 9.8 125 105 101.0 (Note 1) “ℓ” must be selected from the following values: 6, 8, 10, 12, 14, 16, 18, 20, 22, 25, 28, 32, 36, 40, 45, 50, 56, 63, 70, 80, 90, 100, 110, 0 125, 140, 160, 180, 200, 220, 250, 280, 320, 360, or 400. 110 103.0 4 9.5 10.0 131 110 106.0 4.2 4 - 0.54 The dimensional tolerance values for “ℓ” are generally h12 in accordance with JIS B 0401 (Dimensional tolerances and fit). 120 113.0 10.3 10.9 143 120 116.0 (Note 2) The corresponding shaft diameters should be determined in consideration of proper torque for key strength. The the above list indicates (Note 1) The nominal sizes in column “1” are preferable to the sizes in column “2”. The latter may be used when needed. standard diameters for general use and is intended for reference purposes only. (Note 2) The thickness (t) = 1.6 mm. Thickness of 1.5 mm is permissible until determined otherwise. In this case the value “m” is 1.65 mm. (Remark) It is recommended that you avoid using the nominal sizes with parentheses whenever possible. (Remarks) 1. The minimum width of the annular part of the snap ring must not be smaller than the board thickness (t). (Reference) When you need a key with a tolerance smaller than the key tolerance specified above, the tolerance for the key width (b) should be 2. The corresponding shaft dimensions above are shown as recommended dimensions for reference purposes only. h7. In this case, a tolerance for height (h) should be h7 for nominal sizes of 7X7 or smaller and h11 for the sizes of 8X7 or larger.
Appendix-4 Appendix-5 Table 5: Hardness Conversion Chart Table 6: Dimensions of the counterbore and internal thread for the hexagon-headed bolt Brinell hardness Rockwell hardness Rockwell D’ C-scale Vickers A-scale B-scale Shore Tungsten 60 kgf load 100 kgf load hardness hardness Standard balls hardness carbide balls Brale Ball diameter: D (150 kgf) penetrator 1/16 inch 68 940 - - 85.6 - 97 Reference data 67 900 - - 85.0 - 95 H H” Reference data 66 865 - - 84.5 - 92 65 832 - 739 83.9 - 91 d1 64 800 - 722 83.4 - 88 d’ 63 772 - 705 82.8 - 87 62 746 - 688 82.3 - 85 d 61 720 - 670 81.8 - 83 60 697 - 654 81.2 - 81 59 674 - 634 80.7 - 80 58 653 - 615 80.1 - 78 57 633 - 595 79.6 - 76 56 613 - 577 79.0 - 75 55 595 - 560 78.5 - 74 54 577 - 543 78.0 - 72 53 560 - 525 77.4 - 71 Unit: mm 52 544 500 512 76.8 - 69 Nominal size (d) M3 M4 M5 M6 M8 M10 M12 (M14) M16 (M18) M20 (M22) M24 (M27) M30 51 528 487 496 76.3 - 68 Thread pitch (P) 0.5 0.7 0.8 1 1.25 1.5 1.75 2 2 2.5 2.5 2.5 3 3 3.5 50 513 475 481 75.9 - 67 d1 3 4 5 6 8 10 12 14 16 18 20 22 24 27 30 49 498 464 469 75.2 - 66 d’ 3.4 4.5 5.5 6.6 9 11 14 16 18 20 22 24 26 30 33 48 484 451 455 74.7 - 64 47 471 442 443 74.1 - 63 D 5.5 7 8.5 10 13 16 18 21 24 27 30 33 36 40 45 46 458 432 432 73.6 - 62 D’ 6.5 8 9.5 11 14 17.5 20 23 26 29 32 35 39 43 48 45 446 421 421 73.1 - 60 H 3 4 5 6 8 10 12 14 16 18 20 22 24 27 30 44 434 409 409 72.5 - 58 H” 3.3 4.4 5.4 6.5 8.6 10.8 13 15.2 17.5 19.5 21.5 23.5 25.5 29 32 43 423 400 400 72.0 - 57 (Remark) The bolt hole diameters (d’) listed above are in accordance with bolt hole grade 2 in JIS B 1001 (Diameter 42 412 390 390 71.5 - 56 of clearance holes and counterbores for bolts and screws). 41 402 381 381 70.9 - 55 40 392 371 371 70.4 - 54 39 382 362 362 69.9 - 52 38 372 353 353 69.4 - 51 37 363 344 344 68.9 - 50 36 354 336 336 68.4 (109.0) 49 35 345 327 327 67.9 (108.5) 48 34 336 319 319 67.4 (108.0) 47 33 327 311 311 66.8 (107.5) 46 32 318 301 301 66.3 (107.0) 44 31 310 294 294 65.8 (106.0) 43 30 302 286 286 65.3 (105.5) 42 29 294 279 279 64.7 (104.5) 41 28 286 271 271 64.3 (104.0) 41 27 279 264 264 63.8 (103.0) 40 26 272 258 258 63.3 (102.5) 38 25 266 253 253 62.8 (101.5) 38 24 260 247 247 62.4 (101.0) 37 23 254 243 243 62.0 100.0 36 22 248 237 237 61.5 99.0 35 21 243 231 231 61.0 98.5 35 20 238 226 226 60.5 97.8 34 (18) 230 219 219 - 96.7 33 (16) 222 212 212 - 95.5 32 (14) 213 203 203 - 93.9 31 (12) 204 194 194 - 92.3 29 (10) 196 187 187 - 90.7 28 ( 8) 188 179 179 - 89.5 27 ( 6) 180 171 171 - 87.1 26 ( 4) 173 165 165 - 85.5 25 ( 2) 166 158 158 - 83.5 24 ( 0) 160 152 152 - 81.7 24
Appendix-6 Appendix-7