US 20050000072A1 (19) United States (12) Patent Application Publication (10) Pub. N0.: US 2005/0000072 A1 Wollf et al. (43) Pub. Date: Jan. 6, 2005

(54) METHOD, DEVICE, AND TOOL FOR (52) U.S.Cl...... 29/505; 29/566; 409/8; 409/11; CHAMFERING THE FRONT-END EDGES 0F 409/12 THE INTER-TEETH GROOVES OF A GEAR

(76) Inventors: Alfred Wolff, Buchen (DE); Siegfried (57) ABSTRACT Thesies, SchWarZenbek (DE); Wolfgang Carmincke, Scharnebeck (DE) A method for the manufacture of a toothed gear from a gear Correspondence Address: blank Wherein the gear blank loaded into a machine tool and VIDAS, ARRETT & STEINKRAUS, RA. rotationally driven is machined by a hobbing cutter disposed 6109 BLUE CIRCLE DRIVE on a rotationally driven tool shaft and the rough-hobbed SUITE 2000 gear, once produced, is subsequently cleared of burr by MINNETONKA, MN 55343-9185 (US) means of a rotationally driven deburring tool by causing it to chamfer the front-end edges of the inter-teeth grooves, (21) Appl. No.: 10/874,653 Wherein the number of revolutions of said deburring tool and (22) Filed: Jun. 22, 2004 rough-machined gear has a constant ratio, Wherein the removal of burr is performed on said rough-machined gear (30) Foreign Application Priority Data invariably loaded on said machine tool in a continuous pass by using a deburring tool Which is similar to a side milling Jul. 5, 2003 (GH) ...... 103 30 474.6 cutter, has cutting teeth, and is ?xedly disposed for rotation on the shaft of said hobbing cutter, Wherein the front-end Publication Classi?cation edges of the inter-teeth grooves are successively machined in the Way of a gear hobbing process, and Wherein said shaft (51) Int. Cl? ...... B23F 5/00; B23F 19/00; is changed from the gear hobbing setting over to a burr B23P 23/00 removal setting. Patent Application Publication Jan. 6, 2005 Sheet 1 0f 3 US 2005/0000072 A1 Patent Application Publication Jan. 6, 2005 Sheet 2 0f 3 US 2005/0000072 A1

FIG.3 Patent Application Publication Jan. 6, 2005 Sheet 3 0f 3 US 2005/0000072 A1 US 2005/0000072 A1 Jan. 6, 2005

METHOD, DEVICE, AND TOOL FOR [0008] It is the object of the invention to indicate a method CHAMFERING THE FRONT-END EDGES OF THE for the manufacture of a toothed gear from a gear blank in INTER-TEETH GROOVES OF A GEAR Which the removal of burr involves a distinctly loWer expenditure in manufacture and machining equipment. CROSS-REFERENCE TO RELATED APPLICATIONS BRIEF SUMMARY OF THE INVENTION [0001] Not applicable. [0009] In the inventive method, the removal of burr is performed on the rough-machined gear invariably loaded on STATEMENT REGARDING FEDERALLY the machine tool in a continuous pass by using a deburring SPONSORED RESEARCH tool Which is similar to a side milling cutter, has cutting teeth, and is ?xedly disposed for rotation on the shaft of the [0002] Not applicable. hobbing cutter. As is knoWn the tool shaft is adjustable in space. After the hobbing procedure, the tool shaft is adjusted BACKGROUND OF THE INVENTION so as to alloW the deburring tool, by rotating it With the shaft, to be brought into engagement With the front-end edges of [0003] The invention relates to a method for the manu the inter-teeth grooves noW in order to successively machine facture of a toothed gear device for the manufacture of a the front-end edges of the inter-teeth grooves in the Way of toothed gear and a tool for deburring the front-end edges of a hobbing process. the inter-teeth grooves of a gear. [0010] The inventive process has signi?cant advantages. [0004] It is knoWn to produce toothed gears by means of Although a separate deburring tool is needed to remove the so-called hobbing cutters. Hobbing cutters have a Worm as burr the tool is employed on the same machine tool on Which a geometrical body to start from. When the Worm is given the hobbing process is carried out. This drastically reduces clamping grooves hobbed teeth are obtained Which, When the need for machining equipment as compared to conven subjected to relieving, become then able to cut. After gear tional methods. The expenditure in manufacture is consid like Workpieces are hobbed the front-end edges of the erably reduced as Well. Transport times, setting times, and inter-teeth grooves and tooth heads Will have sharp edges, retooling times for the deburring process after the end of the speci?cally at the side at Which the hobbing tool exits. It is hobbing process become largely unnecessary. This saves knoWn to remove the burr in a manual operation. Further, it signi?cant time for manufacture. Since the burr is removed is knoWn to remove the burr by grinding, pro?le milling or continuously in the pass the cycle time for deburring a by means of press rolling. toothed gear is by far smaller than in conventional processes. [0005] DE 199 02 035 has made knoWn a method for the [0011] It is unnecessary either to transfer the Workpiece to removal of burr from the front-end edges of the inter-teeth remove the burr from either side of the toothed gear, but the grooves on gear-like Workpieces in Which the tool’s axis of rough-machined gear may remain mounted in its position, rotation is operated at a ?xed radial spacing from the according to an aspect of the invention, because the front Workpiece’s axis of rotation and at a ?xed axial spacing from end edges are ?rst machined on one side of the rough the tool’s front-end face at a constant speed ratio With machined gear and then are the front-end edges on the other respect to the Workpiece Which is continuously driven by side. The deburring tool is moved toWards the front-end rotation, a cutter plate seated on the tool axis forming cutting edges, in one case, and is moved aWay from the front-end edges for chamfering the groove root edge at a predeter edges from betWeen the inter-teeth grooves, in the other mined root chamfering angle, chamfering a ?rst groove case. ?ank edge at a predetermined ?ank chamfering angle, and chamfering a second groove ?ank edge opposed to the ?rst [0012] The inventive method also makes it possible to one at a predetermined ?ank chamfering angle. At this point, perform chamfering in tWo or more steps by advancing the chamfering is not continuous, but is discontinuous in a deburring tool by a predetermined amount prior to each pass. single-piece procedure. This alloWs to choose the siZe of the chamfer nearly ran domly. [0006] All knoWn devices have in common that they are machined on a device Which is separated from the hobbing [0013] The inventive device, speci?cally for implement machine. Normally, the manufacturing process of a toothed ing the inventive method, provides means for ?xedly mount gear is such that a blank is ?rst turned on a lathe and ?nally ing a disc-shaped deburring tool having teeth for rotation is machined by a hobbing cutter on a machine tool. After next to the hobbing cutter on the tool shaft Which as Was hobbing, deburring is done in a separate device and is then mentioned previously is knoWn to be adjustable in space folloWed by shaving as a micro-machining operation Which along all of the three axes. According to an aspect of the can be performed again on the same machine tool on Which invention, the deburring tool is a separate tool Which is the hobbing procedure is carried out. separately and ?xedly disposed on said tool shaft for rota tion. Alternatively, it may also be brought into a rotary [0007] The methods Which are knoWn exhibit consider engagement With the hobbing cutter, eg by jaWs Which are able disadvantages. A separate deburring device Will natu formed at the front ends facing each other of the hobbing rally increase the need for machining equipment. Expendi cutter and deburring tool. Finally, according to another ture in manufacture arises by the need to transfer the aspect of the invention, the deburring tool can also be rough-hobbed gear to the deburring device, Which requires formed integrally With the hobbing cutter. a certain time for transport and retooling. Afurther draWback of the knoWn method is that it has a relatively large cycle [0014] The deburring tool for implementing the inventive time. method has cutting teeth and clamping grooves at an equal US 2005/0000072 A1 Jan. 6, 2005

circumferential spacing at the circumference. The cutting [0026] In FIG. 2, a gear blank is outlined at 2 Which is teeth run helically in a circumferential direction. The cutting loaded on a machine tool in a manner Which is not shoWn in edges formed at the side Which is the front side of the teeth detail and is rotationally driven about an aXis 4. The aXis is in a rotational direction are disposed on a common ?y circle. perpendicular to the plane of the draWing, for eXample. A The deburring tool has multiple leads, at least one tooth shaft 6 of the machine tool has mounted thereon a hobbing being provided for each lead. If the deburring tool has one cutter 8. The shaft 6 can be shifted in space as is outlined by tooth per lead one tooth each Will mesh With a tooth space the tWo-ended arroW 7, the tWo-ended arroW 5, and the of the toothed gear during the synchronized rotational directions shoWn at 3. Rotating the tool shaft 6 and provid motion of the deburring tool and toothed gear. If tWo or more ing the correct setting and the correct feed motion and teeth are provided for each lead all of the teeth Will interact advancement produces a spur gear. This process is generally With a inter-teeth groove each With a certain front-end edge knoWn and is not thought to be discussed in detail. area of the inter-teeth groove being associable With each [0027] The shaft 6 has mounted thereon a deburring tool tooth. In other Words, the teeth of a lead machine successive 10. It serves for the removal of burr from the front-end edges areas of the front-end edges. of the inter-teeth grooves of the toothed gear produced [0015] Since the front-end edges of the tooth heads pos before, reference to Which Will be made in FIGS. 3 to 5 sibly require to be chamfered as Well an aspect of the Which folloW beloW. invention provides that cutting edges be provided neXt to the [0028] The disc-shaped deburring tool 10 is represented in teeth to chamfer the front-end edges of the tooth heads of the a perspective vieW in FIG. 3. Each tooth 12 is on a helical toothed gear. line. Clamping grooves 22 of a V-shaped contour and a [0016] In a straight-toothed gear, the pro?le of the cutting rounded bottom are located betWeen the teeth 12. When the edges of the cutting teeth is symmetric to the central plane deburring tool 10 rotates the edges of the front-end sides of of the deburring tool. On the other hand, it is asymmetric in the teeth 12 de?ne cutting edges 14 each. The peculiar a helically toothed gear. feature of a deburring tool similar to a side milling cutter is that each tooth 12 is disposed on a lead of its oWn. Since nine [0017] The further advantage of the inventive deburring teeth 12 are provided at a uniform circumferential spacing tool is that it can be resharpened on the machine tool. This the deburring tool 10 is nine-leaded. A further peculiarity is admittedly causes a certain removal rate, but the pro?le that the cutting edges 14 or predetermined points of the teeth required remains unchanged. 12 are disposed on a common ?y circle. [0018] The inventive toothed gear equals a side milling [0029] FIG. 3 also outlines the three aXes along Which the cutter Which, hoWever, has the helically extending teeth deburring tool 10 can be moved by means of the tool shaft disposed in such a Way that identical points of all teeth are 6 shoWn in FIG. 1. Along aXes 26, 28, the feed motion is on the same ?y circle. This is contrary to a side milling cutter effected With respect to a toothed gear 30 Which is provided as a tooth-forming tool. With helical teeth 32 and in Which the front-end edges of the inter-teeth grooves are shoWn as being chamfered or BRIEF DESCRIPTION OF THE SEVERAL deburred already. This chamfer is outlined at 34 in FIG. 3. VIEWS OF THE DRAWINGS The toothed gear 30 of FIG. 3 rotates in a clockWise sense as does the deburring tool 10. [0019] The invention Will be described in more detail beloW With reference to an embodiment shoWn in the [0030] According to the hobbing procedure of FIG. 1, the draWings. tool shaft 6 is shifted such as to move the deburring tool 10 to a position as is depicted in FIG. 3. While the front-end [0020] FIG. 1 extremely schematically shoWs a hobbing edges of the inter-teeth grooves are being machined the and deburring device according to the invention. toothed gear 30 and deburring tool 10 rotate at a predeter [0021] FIG. 2 shoWs the reference pro?le in a normal mined speed ratio so that one tooth 12 each Works on the section of a cutting tooth of a deburring tool of FIG. 1. front-end edges of an inter-teeth groove. It goes Without saying that the deburring tool 10 and teeth 12 are designed [0022] FIG. 3 shoWs the arrangement of a toothed gear in accordance With the parameters of the teeth of the toothed and a deburring tool according to the invention during the gear 30 to enable the desired engagement With the front-end deburring procedure in a perspective vieW. edges of the inter-teeth grooves. [0023] FIG. 4 shoWs some part of the vieW of FIG. 3 in [0031] In the representation of FIG. 3, the front-end edges a enlarged perspective vieW. are initially machined on the upWardly facing side of the toothed gear 30. If it is also desired to chamfer the front-end [0024] FIG. 5 also shoWs some part of FIG. 3, but as edges on the opposed, loWer side the toothed gear 30 Will not vieWed obliquely from top. be mounted as turned through 180° here, but it remains in the position Which is shoWn. Machining it merely requires DETAILED DESCRIPTION OF THE that the deburring tool 10 be moved doWnWards relative to INVENTION the toothed gear 30 in the direction of the aXis 28 so that the [0025] While this invention may be embodied in many teeth 12, While deburring is underWay, are moved outWardly different forms, there are described in detail herein a speci?c as vieWed from the grooves 32 (doWnWardly in FIG. 3) in preferred embodiment of the invention. This description is order to produce a chamfer also at this point. an eXempli?cation of the principles of the invention and is [0032] If it is intended to Work out a chamfer to the tooth not intended to limit the invention to the particular embodi heads 36 it can be done by means of cutting edges 38 and 40 ment illustrated Which are disposed on the tWo sides of the cutting edge 14. US 2005/0000072 A1 Jan. 6, 2005

[0033] It is perceivable to provide tWo or more teeth per Wherein the number of revolutions of said deburring tool and lead unlike the Way shown in FIGS. 3 to 5. While machining rough-machined gear has a constant ratio, characteriZed in is done all of the teeth of a lead Will come into successive that the removal of burr is performed on said rough-ma engagement With the front-end edge of a inter-teeth groove. chined gear invariably loaded on said machine tool in a continuous pass by using a deburring tool Which is similar [0034] FIG. 2 shoWs the reference pro?le of a tooth 12 in to a side milling cutter, has cutting teeth, and is ?Xedly a normal section. It can be recogniZed that the pro?le is not disposed for rotation on the shaft of said hobbing cutter, symmetric With respect to the aXis 16 Which passes through Wherein the front-end edges of the inter-teeth grooves are the central plane, but presents a steeper ?ank 18 and a less successively machined in the Way of a gear hobbing process, ascending ?ank 20. Nor is the apeX area symmetric. The and Wherein said shaft is changed from the gear hobbing steeper ?ank 18 includes a smaller radius than does the less setting over to a burr removal setting. ascending ?ank 20. A pro?le of this type is needed for a 2. The method of claim 1, characteriZed in that the helically toothed gear. On the other hand, a symmetric removal of burr from said front-end edges is performed on pro?le may be employed if a burr-toothed gear requires one side of said rough-machined gear by advancing said deburring. deburring tool against this side of said rough-machined gear [0035] The above disclosure is intended to be illustrative and the removal of burr from said front-end edges of said and not exhaustive. This description Will suggest many inter-teeth grooves on the opposite side of said rough variations and alternatives to one of ordinary skill in this art. machined gear is performed in a second burr removal setting All these alternatives and variations are intended to be by advancing said deburring tool outWardly from said inter included Within the scope of the claims Where the term teeth grooves aWay from the other side. “comprising” means “including, but not limited to”. Those 3. The method according to claim 1, characteriZed in that familiar With the art may recogniZe other equivalents to the chamfering is performed in tWo or more passes, said deburr speci?c embodiments described herein Which equivalents ing tool being advanced by a predetermined amount prior to are also intended to be encompassed by the claims. each pass. [0036] Further, the particular features presented in the 4. A device for the manufacture of a toothed gear from a gear blank on a machine tool Which has means for loading dependent claims can be combined With each other in other and rotationally driving a gear blank and a rotationally manners Within the scope of the invention such that the driven tool shaft adjustable in space on Which a hobbing invention should be recogniZed as also speci?cally directed to other embodiments having any other possible combina cutter can be ?Xedly mounted for rotation, characteriZed in that more means are provided for ?Xedly mounting a disc tion of the features of the dependent claims. For instance, for purposes of claim publication, any dependent claim Which shaped deburring tool (10) having teeth (12) for rotation neXt to said hobbing cutter folloWs should be taken as alternatively Written in a multiple 5. The device according to claim 4, characteriZed in that dependent form from all prior claims Which possess all antecedents referenced in such dependent claim if such a separate deburring tool (10) is disposed on said tool shaft multiple dependent format is an accepted format Within the (6). jurisdiction (e.g. each claim depending directly from claim 6. The device according to claim 5, characteriZed in that a rotary connection is de?ned betWeen said hobbing cutter 1 should be alternatively taken as depending from all and said deburring tool at the front ends facing each other. previous claims). In jurisdictions Where multiple dependent 7. The device according to claim 4, characteriZed in that claim formats are restricted, the folloWing dependent claims said deburring tool is formed integrally With said hobbing should each be also taken as alternatively Written in each singly dependent claim format Which creates a dependency cutter. 8. A deburring tool for the implementation of the method from a prior antecedent-possessing claim other than the according to claim 1, characteriZed in that it has cutting teeth speci?c claim listed in such dependent claim beloW. (12) and clamping grooves (22) in a helical peripheral run at [0037] This completes the description of the preferred and equal circumferential spacings at the circumference, Which alternate embodiments of the invention. Those skilled in the are disposed in multiple leads having at least one tooth (12) art may recogniZe other equivalents to the speci?c embodi per lead, the cutting edges (14) formed at the side Which is ment described herein Which equivalents are intended to be the front side of the teeth (12) in a rotational direction being encompassed by the claims attached hereto. disposed on a common ?y circle. 9. The deburring tool according to claim 8, characteriZed What is claimed is: in that at least one more cutting edge (14) is provided neXt 1. A method for the manufacture of a toothed gear from to the cutting edge (14) of the teeth (12) to chamfer the a gear blank Wherein the gear blank loaded into a machine front-end edges of the tooth heads of the toothed gear (30). tool and rotationally driven is machined by a hobbing cutter 10. The deburring tool according to claim 8, characteriZed disposed on a rotationally driven tool shaft and the rough hobbed gear, once produced, is subsequently cleared of burr in that the pro?le of the cutting edges (14) is asymmetric, by means of a rotationally driven deburring tool by causing based on the central plane (16) of the deburring tool (10). it to chamfer the front-end edges of the inter-teeth grooves, * * * * *