Forklift Gabelstapler Chariot Élévateur À Fourche

(19) TZZ _T

(11) EP 2 692 686 B1

(12) EUROPEAN PATENT SPECIFICATION

(45) Date of publication and mention (51) Int Cl.: of the grant of the patent: B66F 9/075 (2006.01) 13.05.2015 Bulletin 2015/20

(21) Application number: 13020060.3

(22) Date of filing: 24.07.2013

(54) Forklift Gabelstapler Chariot élévateur à fourche

(84) Designated Contracting States: • Ikegami, Masato AL AT BE BG CH CY CZ DE DK EE ES FI FR GB Yokosuka-shi, Kanagawa, 237-8555 (JP) GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR (74) Representative: Carstens, Dirk Wilhelm Wagner & Geyer (30) Priority: 31.07.2012 JP 2012169890 Gewürzmühlstraße 5 80538 München (DE) (43) Date of publication of application: 05.02.2014 Bulletin 2014/06 (56) References cited: JP-A- 2004 122 916 JP-A- 2004 260 969 (73) Proprietor: SUMITOMO HEAVY INDUSTRIES, LTD. US-A- 5 558 174 US-A- 6 148 940 Tokyo 141-6025 (JP) US-A1- 2008 120 974

(72) Inventors: • Ishizuka, Masayuki Yokosuka-shi, Kanagawa, 237-8555 (JP)

Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the Implementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). EP 2 692 686 B1

Printed by Jouve, 75001 PARIS (FR) 1 EP 2 692 686 B1 2

Description ly, and are synchronized with the respective driving motors. The driving motors and a controller are disposed in BACKGROUND proximity to each other. The pipes for cooling the driving motors and the controller are serially disposed. Technical Field 5 [0010] US 5,558,174 A discloses a drive train assembly for motorized vehicles, for example lift trucks. The [0001] The present invention relates to a forklift. rotational movement of the output shaft of a motor, for example an electrical motor, is transmitted to a drive Description of the Related Art wheel by a single drive shaft having at one end a gear 10 interface assembly consisting of a gear on the end of the [0002] The related art discloses a forklift including a output shaft and a gear on an end of the drive shaft, and wheel driving device that has a traveling motor and drives at the other end of the drive shaft by a second gear in- a wheel, and a cargo handling device that has a motor terface assembly consisting of a gear on the drive shaft for an operating machine (cargo handling motor) and and a gear fixedly mounted on the inside of the rim of the drives a cargo handling mechanism. 15 drive wheel. The drive wheel is independently rotatably [0003] The traveling motor is operated with a battery supported on a spindle mounted to the chassis of the mounted on avehiclebodyasadrivingsource, anddrive- vehicle. sawheel (specifically, front wheels) of the forklift. [0004] The cargo handling motor is driven independ- SUMMARY ently from the traveling motor, and drives the cargo han- 20 dling mechanism for tilting of a mast of the forklift, low- [0011] According to an embodiment of the present in- ering and lifting of a lift bracket (fork) along the mast, or vention, there is provided a forklift including a wheel driv- the like. ing device that includes a traveling motor and drives a [0005] The traveling motor of the related art includes wheel; and a cargo handling device that includes a cargo a cooling fan on the downstream. An air discharge port 25 handling motor and drives a cargo handling mechanism. in the traveling motor and an air suction port in the cargo Here, the cargo handling motor includes a wind gener- handling motor are coupled together with a duct. There- ating mechanism that generates wind by the rotation of by, a wind generated by the cooling fan of the traveling a motor shaft of the cargo handling motor; and a dis- motor cools the traveling motor itself and also cools the charge port that discharges the wind generated by the cargo handling motor. 30 wind generating mechanism, and the cargo handling mo- [0006] It is hard to say that the cooling structure of the tor is arranged in a vehicle body of the forklift so that wind related art based on this development idea is necessarily discharged from the discharge port reaches the wheel a structure in which "the unique structure and operational driving device. characteristic of the forklift" are exactly grasped when a [0012] Although the differences between the cooling drive system and a cooling system of the forklift are seen 35 idea of the invention and the cooling idea of the related as a whole. Particularly, it is an actual situation in which art will be described below in detail, in the present inven- sufficient cooling cannot be performed in respective portion, the direction (flow) of a wind that is generated be- tions of the wheel driving device. tween the traveling motor and the cargo handling motor [0007] It is desirable to provide a forklift that can adopt is "opposite to" the direction of the related art. a more rational cooling structure to cool a wheel driving 40 [0013] The present invention is configured so that at- device effectively. tention is paid to the fact that the cargo handling motor [0008] JP 2004 122 916 A discloses a cooling device is actively moved during a cargo handling operation in for an electric working vehicle and was used as a basis which the wheel driving device becomes severe in terms for the preamble of claim 1. A drive motor is mounted on of overheating, and the wind generated by the rotation a drive part body of a vehicle body, an axle of a drive45 of the motor shaft of the cargo handling motor reaches wheel is firmly fixed on the output shaft, a first cooling the wheel driving device. Thereby, for example, even dur- hole from a cooling air intake port to the drive motor is ing a cargo handling operation in which the traveling formed on the drive part body. A cooling fan mounted on speed is slow, which is unique to the forklift, the wheel the output shaft of the drive motor is disposed on the first driving device can be efficiently cooled by the cargo han- cooling hole, and a second cooling hole from the first 50 dling motor, ) and the wheel driving device that tends to cooling hole to a cooling air exhaust port is formed pass- become thermally severe can be excellently cooled. ing near a control drive on an exhaust pipe mounted on [0014] Accordingto the invention, a forklift thatcan cool the drive part body. the wheel driving device effectively is obtained. [0009] JP 2004 260969 A discloses an apparatus and method for cooling a working electric vehicle. The cooling 55 BRIEF DESCRIPTION OF THE DRAWINGS apparatus comprises pumps for cooling water circulation which are respectively provided for pipes which convey [0015] a first coolant (cooling water) to drive motors, respective-

2 3 EP 2 692 686 B1 4

Fig. 1 is a schematic bottomplan view when a forklift shaft 36 is constituted by a hollow shaft that has a hollow related to an example of an embodiment of the in- portion 36A in this example, and an end portion of the vention is seen from the underside of a vehicle body. hollow portion 36A is formed with a (female) spline 36B Fig. 2 is a cross-sectional view showing chief parts for coupling with an input shaft 42 of the speed reducer of a wheel driving device of the above forklift. 5 22. Fig. 3 is a cross-sectional view showing the config- [0022] In this example, the speed reducer 22 includes uration of a cargo handling motor of the above forklift. an eccentric oscillating type planetary gear speed-reduc- Fig. 4 is a perspective view of the cargo handling ing mechanism, and all those constituent members are motor cut in the cross-section of Fig. 3. housed on the radial inner side within an axial range of Fig. 5 is a schematic bottom plan view equivalent to 10 the wheel 12 except for a portion of the input shaft 42 (an Fig. 1, of a forklift related to an example of another end portion on the motor side). embodiment of the invention. [0023] The speed reducer 22 includes the input shaft Fig. 6 is a schematic bottom plan view equivalent to 42 having a (male) spline 42B that engages the (female) Fig. 1,of a forklift relatedto an example ofstill another spline 36B of the motor shaft 36, an eccentric body 44 embodiment of the invention. 15 formed (integrally in this example) at the input shaft 42, Fig. 7 is a schematic bottom plan view equivalent to an external gear 46 assembled into an outer periphery Fig. 1, of a forklift related to an example of a still of the eccentric body 44 via rollers 45, and an internal further embodiment of the invention. gear 48 with which the external gear 46 internally mesh- Fig. 8 is a cross-sectional view equivalent to Fig. 3, es. of a cargo handling motor related to the example of 20 [0024] In this embodiment, the internal teeth of the in- Fig. 7. ternal gear 48 is constituted by an internal gear body 48A that is integrated with a speed-reducer casing 50, a sup- DETAILED DESCRIPTION porting pin 48B that is rotatably supported by the internal gear body 48A, and outer rollers 48C that are rotatably [0016] Forklifts related to examples of embodiments 25 assembled into an outer periphery of the supporting pin of the invention will be described in detail with reference 48B and constitute the internal teeth of the internal gear to the drawings. 48. The internal teeth (the number of the outer rollers [0017] Fig. 1 is a schematic bottomplan view when a 48C) of the internal gear 48 are slightly (one in this ex- forklift related to an example of an embodiment of the ample) more than the number of the external teeth of the invention is seen from the underside of a vehicle body, 30 external gear 46. and Fig. 2 is a cross-sectional view showing chief parts [0025] A pair of first and second carriers 51 and 52 are of a wheel driving device of the forklift. assembled on both axial sides of the external gear 46 so [0018] The forklift FL1 includes wheel driving devices as to be rotatable relative to the speed-reducer casing 14 and 15 that have traveling motors 10 and 11 and drive 50 via an angular ball bearing 54 and a tapered roller wheels 12 and 13, respectively, and a cargo handling 35 bearing 56. In this example, the first and second carriers device 20 that has a cargo handling motor 16 and drives 51 and 52 are in a fixed state where the carries are inte- a cargo handling mechanism 18, such as a fork. grated with the casing body 24A coupled to the vehicle [0019] The wheel driving devices 14 and 15 have the body (or a member integrated with the vehicle body) 58, same configuration, and are individually provided for left and the speed-reducer casing 50 rotates relative to the and right wheels 12 and 13, respectively. The details on 40 first and second carriers 51 and 52. That is, the speed the wheel driving device 14 side are shown in Fig. 2. reducer 22 is a so-called internal teeth rotation (casing [0020] The wheel driving device 14 has the traveling- rotation) type speed reducer that has the speed-reducer motor 10 driven by a battery that is not shown, and a casing 50 as an output member. The wheel 12 is inte- speed reducer 22 coupled to the traveling motor 10. As grated with the speed-reducer casing 50 via bolts 60 and for the traveling motor 10, a casing 24 is constituted by 45 a tire frame 62. a plurality of (three in this example) casing bodies 24A [0026] The speed-reducer casing 50 forms a speed- to 24C and cover bodies 24D and 24E. The respective reducer inner space (second space) SP2 sealed via the casing bodies 24A to 24C and the respective cover bod- seal members 66 and 68 together with the second carrier ies 24D and 24E are sealed by a plurality of bolts 26A to 52 and a cover body 50A. The speed-reducer inner space 26D and seal members 28A to 28E to form a motor inner 50 SP2 communicates with the aforementioned motor inner space (first space) SP1. Lubricating oil is enclosed in the space SP1. That is, the motor inner space (first space) motor inner space SP1. That is, the traveling motor 10 SP1 and the speed-reducer inner space (second space) is a liquid cooling motor (oil-bath motor) that is cooled by SP2 communicate with each other, and common lubri- lubricating oil. cating oil is able to circulate through both the spaces of [0021] In addition, reference numeral 32 in the drawing 55 the motor inner space SP1 and the speed-reducer inner designates a stator, reference numeral 34 designates a space SP2. rotor, and reference numeral 36 designates a motor shaft [0027] An inner pin hole 46A and a carrier pin hole 46B (an output shaft of the traveling motor 10). The motor are formed at positions offset from an axial center O1 of

3 5 EP 2 692 686 B1 6 the input shaft 42 in the external gear 46. Inner pins 70 [0033] More specifically, since the cargo handlingmo- integrated with the first carrier 51 are loosely fitted into tor 16 rotates normally and reversely, even when the mo- the inner pin hole 46A in a state where some pins thereof tor rotates in any direction, the formation angle (shape) come into contact with the external gear 46. Carrier bolts of the rotor fins 76 and 77 and the shape of the straight- 72 that connect the first and second carriers 51 and 52 5 ening vanes 78 and 79 are set so that a wind flow in the are loosely fitted into the carrier pin hole 46B in non- same direction is generated. The straightening vanes 78 contact with the external gear 46. and 79 are bent on the radial inner side so as to be closer [0028] By virtue of this configuration, the relative rota- the rotor fin 76, and are assembled in such a shape that tion of the internal gear 48 (speed-reducer casing 50) to a negative pressure is relatively easily formed further to- the external gear 46 whose rotation on its own axis is 10 ward on the discharge ports 88 and 89 side (radial outer restrained by the inner pins 70 can be taken out as the side) than the bent portion. In other words, in this em- rotation of the wheel 12 fixed to the speed-reducer casing bodiment, the formation angle (shape) of the rotor fins 50. 76 and 77 and the shape of the straightening vanes 78 [0029] On the other hand, the cargo handling motor 16 and 79 are set so that wind suctioned in the axial direction of the cargo handling device 20 that drives the cargo15 from the suction ports 86 and 87 (arrows A1 and A2) runs handling mechanism 18 of the forklift FL1, as shown in around to (arrows A3 and A4) to the axial inner side of Fig. 1, is arranged between the left and right wheel driving the straightening vanes 78 and 79 at a radial central por- devices 14 and 15 in a left-and-right direction Y1 of the tion of the cargo handling motor 16, flow to the radial forklift FL1. More specifically, the cargo handlingmotor outer side while heat-exchanging with, the rotor 82, the 16 is arranged at a position slightly further toward the 20 coils 85, and the like, and are discharged from the dis- rear of the vehicle body than an axial center 02 (axle: the charge ports 88 and 89 to the radial outer side (arrows same as the axial center O1 of the input shaft 42) of the A5 and A6). left and right wheel driving devices 14 and 15 between [0034] Referring backto Fig. 1,this embodiment iscon- (center 03) the left and right wheel driving devices 14 and figured so that the wind indicated by arrow A5 among the 15 such that an axial direction X1 of the cargo handling 25 wind (arrows A5 and A6) discharged from the discharge motor 16 is turned to a front-and-rear direction X2 of the ports 88 and 89 of the cargo handling motor 16 reaches forklift FL1. the wheel driving devices 14 and 15. More specifically, [0030] As shown in Figs. 3 and 4, the cargo handling- in the forklift FL1 related to this embodiment, the cargo motor 16 includes a rotor 82 on the inner side of the stator handling motor 16 is arranged such that its own axial 80, and an output shaft 84 integrated with the rotor30 direction X1 is turned toward the front-and-rear direction 82bypress-fitting. Reference numeral 85 designates X2 of the vehicle body 58, slightly behind the axle 02 on coils (ends). the center 03 of the forklift FL1 in the left-and-right direc- [0031] A casing 83 of the cargo handling motor 16 has tion Y1. The wind (arrow A5) discharged from the front a cylindrical casing body 83A parallel to the axial direction discharge port 88 of the cargo handling motor 16 is dis- X1 of the cargo handling motor 16, and side covers 83B 35 charged in the left-and-right direction Y1 of the vehicle and 83C that constitute end faces in the axial direction. body 58 toward the left and right wheel driving devices In this embodiment, eight suction ports 86 and 87 are 14 and 15, and reaches the wheel driving devices 14 and formed in a circumferential direction at equal intervals in 15. side covers 83B and 83C, respectively. In addition, al- [0035] Next, the operation of the forklift FL1 will be de- though the outer peripheral surface of the stator 80 of 40 scribed. the cargo handling motor 16 of the present embodiment [0036] If the motor shaft 36 of the traveling motor 10 is exposed to the outside (is not configured to be covered rotates, the input shaft 42 of the speed reducer 22 cou- with the casing), the invention is not limited to such a pled to the motor shaft 36 via the splines 36B and 42B configuration, and a casing may also be arranged on the rotates, and the eccentric body 44 integrated with the outside of the stator 80. 45 input shaft 42 rotates. If the eccentric body 44 rotates, [0032] Additionally, a plurality of discharge ports 88 the external gear 46 internally meshes with the internal and 89 are formed at positions corresponding to both gear 48 while oscillating via the rollers 45. axial sides of the stator 80 of the casing body 83A. Rotor [0037] The rotation of the external gear 46 on its own fins 76 and 77 are provided at the both axial ends of the axis is restrained by the pair of first and second carriers rotor 82. The rotor fins 76 and 77 constitute a wind gen- 50 51 and 52 via the inner pins 70. For this reason, the ex- erating mechanism W1 that generates wind together with ternal gear 46 performs only oscillation without rotating straightening vanes 78 and 79 by the rotation of the out- on its own axis. As a result, a phenomenon in which the put shaft 84 (rotor 82) of the cargo handling motor 16. meshing position between the external gear 46 and the That is, the cargo handling motor 16 is an air-cooling internal gear 48 shifts sequentially occurs, and the inter- motor having the wind generating mechanism W1 (the 55 nal gear 48 (speed-reducer casing 50) rotates by an rotor fins 76 and 77 and the straightening vanes 78 and amount equivalent to the number-of-teeth difference be- 79) that generates wind by the rotation of the output shaft tween the external gear 46 and the internal gear 48 when- 84. ever the input shaft 42 (eccentric body 44) makes one

4 7 EP 2 692 686 B1 8 rotation. As a result, the speed reduction rotation of 1/ inwhich the wheeldriving device 14 (15)becomes severe (N+1) is realized. The rotation of the speed-reducer cas- in terms of overheating, and the wind generated by the ing 50 is transmitted to the tire frame 62 via the bolts 60, cargo handling motor 16 reaches the wheel driving de- and the wheel 12 (and 13) integral with the tire frame 62 vice 14 (15). Although this flow is exactly opposite to the is driven. 5 flow of cooling wind in the related art, during a cargo [0038] On the other hand, the cargo handling motor 16 handling operation in which the rotation of the traveling isdriven independentlyfrom thetraveling motor 10 during motor 10 (11) tends to become slow due to this, the wheel a cargo handling operation. If the output shaft 84 (rotor driving device 14 (15) can be efficiently cooled. 82) of the cargo handling motor 16 rotates, the air outside [0044] In the above embodiment, the effective actions the cargo handling motor 16 is suctioned into the cargo 10 as follows are additionally obtained. handling motor 16 along the axial direction from the suc- [0045] As is clear from Fig. 2, in the forklift FL1 related tion port 86 formed in an axial end portion of the cargo to this embodiment, all the constituent elements of the handling motor 16 (arrow A1 and A2), runs around from speed reducer 22 of the wheel driving device 14 except the radial central portion of the straightening vanes 78 for a portion of the input shaft 42 are housed on the radial and 79, and cools the coils 85 or the like of the cargo15 inner side within the axial range L1 of the wheel 12. That handling motor 16 (arrows A3 and A4). In this embodi- is, a configuration is provided in which the fact itself that ment, particularly, the wind discharged from the dis- wind is applied to the speed reducer 22 is very difficult. charge port 88 located on the front side of the vehicle As a result, a situation is incurred in which, particularly, body 58 flows along the left-and-right direction Y1 of the the speed reducer 22 in the wheel driving device 14 easily vehicle body 58 toward the radial outer side of the cargo 20 overheats somewhat. If the speed reducer 22 overheats handlingmotor 16, andreaches the wheel drivingdevices somewhat, the temperature of the lubricating oil within 14 and 15 (arrow A5). the speed reducer 22 rises, the viscosity of the lubricating [0039] Here, in order to make the actions of the present oil decreases, and formation of an oil film on power trans- embodiment more easily understood, the cooling struc- mission members within the speed reducer 22 becomes ture of the present embodiment will be described in detail 25 difficult (when the rotational speed of the wheel driving while beingcompared with a related-artcooling structure. device 14 is low like during a cargo handling operation, [0040] The related art is based on a technical idea de- the formation of the oil film becomes particularly difficult). scribed in Paragraph [0003] of the related art as follows: This causes a decrease in lifespan and a decline in trans- "although a cooling fan also always operates to always mission efficiency. cool a traveling motor 11 in the traveling motor that is 30 [0046] In order to overcome this problem, in the above always operating, since a motor for a operating machine embodiment, hybrid cooling of the "liquid cooling + forced stops when an operation in the operating machine is not air cooling" by the synergic action with the cargo handling performed in the motor for an operating machine, the motor 16 is performed. cooling fan also comes to stop, and thereby, the motor [0047] That is, in the above embodiment, first (a) the for an operating machine cannot always be cooled, and 35 traveling motor 10 itself is not probably air-cooled by a the motor for an operating machine heats and fails". cooling fan (in which wind does not reach easily) but is [0041] However, since the cargo handling motor stops liquid-cooled using lubricating oil. In addition, (b) the mo- when only traveling is performed without performing a tor inner space SP1 of the traveling motor 10 and the cargo handling operation in the forklift, the problem of speed-reducer inner space SP2 of the speed reducer 22 overheating of the cargo handling motor does not easily 40 are made to communicate with each other, and lubricat- occur initially. Additionally, since the cargo handling mo- ing oil is enabled to circulate through the two spaces SP1 tor 16 itself can generate wind in a case where a cargo and SP2. On the other hand, (c) the cargo handling motor handling operation is performed in parallel during 16 is air-cooled by the rotor fins 76 and 77, and (d) wind traveling, the problem of overheating of the cargo han- that is generated and discharged in the cargo handling dling motor does not easily occur even in this case. 45 motor 16 is applied to, particularly, the portion of the [0042] On the other hand, a problem in the related-art traveling motor 10 in the wheel driving device 14. structure is that it is not possible to cope with a state [0048] Thereby, in the wheel driving device 14, wind where "traveling often becomes a low speed during a blown off from the discharge port 88 of the cargo handling cargo handling operation, wind itself generated by the motor 16 can be intensively applied to the traveling motor traveling motor decreases, and a wheel driving device 50 10 (to which wind is easily applied) exposed from the itself overheats somewhat". As long as traveling is made wheel 12, and the lubricating oil of the traveling motor 10 even during low-speed traveling, both the traveling motor can be effectively cooled. Thus, since the cooled lubri- 11 and the speed reducer 22 heats up. Moreover, the cating oil is in the same bath as the lubricating oil of the cargo handling operation is a main operation of the forklift speed reducer 22, eventually, the whole wheel driving FL1, and often lasts for a prolonged time by its nature. 55 device 14 including the traveling motor 10 and the speed [0043] The present embodiment is configured so that reducer 22 can be more reliably and favorably cooled. attention is paid to the fact that the cargo handling motor [0049] Various variations are considered in the inven- 16 is actively moved during a cargo handling operation tion.

5 9 EP 2 692 686 B1 10

[0050] An example of another embodiment of the in- invention is shown in Fig. 7. vention is shown in Fig. 5. In addition, in the subsequent [0057] Even in the forklift FL4 related to this embodi- description of variations, members using the same ref- ment, a cargo handling motor 16b is arranged such that erence numerals mean being conceptually the same as an axial direction X4 of the cargo handling motor 16b is the members that are basically already described. 5 turned to the left-and-right direction Y1 of forklift FL4. [0051] A forklift FL2 related to this embodiment is dif- However, unlike the previous embodiment of Fig. 6, the ferent from the previous embodiment in that casings 90 distances to the left and right wheel driving devices 14 and 91 of the traveling motors 10 and 11 of the wheel and 15 from the cargo handling motor 16b are different. driving devices 14 and 15 have fins 90A and 91A that That is, the cargo handling motor 16b is arranged at a extend in the axial direction. In the previous embodiment, 10 position shifted from the center 03 of the vehicle body 58 as already described, the cargo handling motor 16 is ar- in the left-and-right direction Y1. ranged between the left and right wheel driving devices [0058] Thus, in the cargo handling motor 16b related 14 and 15 in the left-and-right direction Y1 of the forklift to this embodiment, as shown in Fig. 8, respective dis- FL2 such that the axial direction X1 of the cargo handling charge ports 96 and 97 have their own discharge angles motor 16 is turned to the front-and-rear direction X2 of 15 α1 and α2 ( α1<α2) other than the radial direction in order the forklift FL2. Additionally, the cargo handling motor 16 to discharge wind toward the wheel driving devices 14 is provided with the discharge ports 88 and 89 so that and 15, respectively. The discharge angles α1 and α2 the wind generated by the wind generating mechanism can be realized, for example, by changing the arrange- W1 is discharged in the radial direction (arrows A5 and ment angle or bent shape of the straightening vanes 78 A6). 20 and79 of the cargo handling motor 16b, andthe formation [0052] Accordingly, the wind (arrow A5) discharged angle of the cross-sections of the discharge ports 96 and from the discharge port 88 of the cargo handling motor 97 in a casing 83. As a result, wind discharged from the 16 is applied to the traveling motors 10 and 11 as wind cargo handling motor 16 can be made to reach the re- that flows generally in the left-and-right direction Y1. spective wheel driving devices 14 and 15 without causing Therefore, if the casings 90 and 91 of the traveling motors 25 waste as much as possible. 10 and 11 have fins 90A and 91A that extend along the [0059] In this way, in the present invention, the specific axial direction as in this embodiment, contact area can arrangement position or the arrangement direction of the be increased without becoming resistance against wind wheel driving device or the cargo handling motor with that flows in the left-and-right direction Y1, and the cool- respect to the vehicle body are not particularly limited. ing efficiency of the whole wheel driving devices 14 and 30 The fins formed on the traveling motor may also be 15 including the traveling motors 10 and 11 and further formed in arbitrary ways and in arbitrary directions (in the speed reducers 22 and 23 can be further enhanced. consideration of the flow of cooling wind) including the [0053] An example of still another embodiment of the presence/absence of formation. invention is shown in Fig. 6. [0060] Additionally, in all the above embodiments, an [0054] In a forklift FL3 related to this embodiment, the 35 example is shown in which the wheel driving devices are cargo handling motor 16a is arranged such that an axial individually at the left and right wheels, respectively. direction X3 of the cargo handling motor 16a is turned to Since some or many portions of the wheel driving device the left-and-right direction Y1 of the forklift FL3. Addition- (speed reducer) are arranged on the radial inner side of ally, the cargo handling motor 16a itself has the same the wheel, this configuration, as also shown in the above configuration as the cargo handling motor 16 of the pre- 40 example, is a structure in which excellent cooling is par- vious embodiment. In this case, wind (cooling wind) dis- ticularly difficult and the effects of the invention appear charged from the cargo handling motor 16a is applied to most remarkably. However, the forklift related to the in- the traveling motors 10 and 11 as wind that flows gener- vention is not necessarily limited to a configuration in ally in the circumferential direction (front-and-rear direc- which the wheel driving devices are provided individually tion X2). Therefore, in casings 94 and 95 of the traveling 45 at the left and right wheels, respectively, in this way, and motors 10 and 11, if fins 94A and 95A that extend in the may be, for example, a forklift of a configuration of in circumferential direction are formed (rather than forming which the power of one wheel driving device is divided the fins 90A and 91A that extend in the axial direction as and transmitted to two wheels. Even in this case, the in the embodiment of Fig. 5), contact area can be in- cooling of the wheel driving device during a cargo han- creased without becoming resistance against wind that 50 dling operation can be similarly promoted by applying flows in the front-and-rear direction X2. wind discharged from the cargo handling motor to the [0055] In this embodiment, in this regard, since the wheel driving device. traveling motors 10 and 11 have the fins 94A and 95A [0061] Additionally, in the above embodiment, the that extend in the circumferential direction, the cooling wheel driving device itself has a structure in which the efficiency of the whole wheel driving device 14 and 15 55 traveling motor and the speed reducer adopt a liquid cool- including the traveling motors 10 and 11 and further the ing type cooling structure, and the motor inner space (first speed reducers 22 and 23 can be further enhanced. space) within the traveling motor and the speed-reducer [0056] An example of a still further embodiment of the inner space (second space) of the speed reducer are

6 11 EP 2 692 686 B1 12 made to communicate with each other, and lubricating from the cargo handling motor can be utilized without oil are capable of circulating through both the spaces. waste, and higher-efficiency cooling can be performed. However, in the present invention, the wheel driving de- [0064] Additionally, in the above embodiments, the vice does not necessarily have such a cooling structure. cargo handling motor is arranged such that the axial di- For example, the first space within the traveling motor 5 rection thereof is turned to the front-and-rear direction or and the second space within the speed reducer may be the left-and-right direction of the forklift. In the present independent spaces. Moreover, the traveling motor may invention, the arrangement direction of the cargo han- be not liquid-cooled but air-cooled. The speed reducer dling motor is not limited to this, and the cargo handling may also be air-cooled (not liquid-cooled), for example, motor may be arranged in arbitrary directions (angles) at so long as grease can be used. Even in any case, the 10 arbitrary positions so long as the wind generated by the effect of the cooling structure that the wheel driving de- wind generating mechanism of the cargo handling motor vice itself has uniquely can be further enhanced by ap- reaches the wheel driving device. plying wind discharged from the cargo handling motor to the wheel driving device during a cargo handling operation. 15 Claims [0062] Moreover, in the above embodiments, the wind generating mechanism that generates wind by the rota- 1. A forklift (FL1) comprising: tion of the motor shaft of the cargo handling motor is constituted by the rotor fins and straightening vanes that a wheel driving device (14, 15) that includes a are attached to the rotor in the cargo handling motor.20 traveling motor (10, 11) and drives a wheel (12, However, in the present invention, whether the wind gen- 13); and erating mechanism of the cargo handling motor adopts a cargo handling device (20) that includes a car- any kind of configuration is also not particularly limited. go handling motor (16) and drives a cargo han- That is, for example, when there is a margin in terms of dling mechanism (18), space, a configuration may be adopted in which an ex- 25 characterized in that: clusive "cooling fan" and an exclusive "fan cover" are attached to the motor shaft made to protrude out of the the cargo handling motor (16) includes: casing (side cover) of the cargo handling motor. In this case, the cooling fan and its fan cover are equivalent to a wind generating mechanism (W1) the "wind generating mechanism that generates a wind 30 that generates wind by the rotation of a by the rotation of the motor shaft of the cargo handling motor shaft (84) of the cargo handling motor" in the present invention, or an air outflow hole of motor (16); and the fan cover, or an opening formed between an outer a discharge port (88) that discharges periphery of the casing of the cargo handling motor and the wind generated by the wind gener- an inner periphery of the fan cover is equivalent to the 35 ating mechanism (W1), and "discharge port that discharges a wind generated by the wind generating mechanism" in the present invention. wherein the cargo handling motor (16) is ar- [0063] Additionally, in the above embodiments, wind ranged in a vehicle body (58) of the forklift (FL1) discharged from the discharge port of the cargo handling so that wind discharged from the discharge port motor is directly released toward the wheel driving device 40 (88) reaches the wheel driving device (14, 15). side. However, in the present invention, a duct directed from the discharge port to the wheel driving device, a 2. The forklift according to Claim 1, duct that reaches the wheel driving device, or the like comprising two wheel driving devices (14, 15), may be appropriately formed so that the wind discharged wherein the wheel driving devices (14, 15) are indi- from the discharge port of the cargo handling motor more 45 vidually provided at the left and right wheels (12, 13), reliably reaches the wheel driving device. Even if not respectively. closed like the duct, a guide plate that appropriately changes the flow direction of wind may be attached. 3. The forklift according to Claim 2, Thereby, the wind discharged from the cargo handling wherein each wheel driving device (14, 15) includes motor can be applied in a concentrated manner to a most 50 a speed reducer (22, 23) that is coupled to the effective portion of the wheel driving device without traveling motor (10, 11), and waste. Additionally, for example, wind that comes out wherein a first space (SP1) within the traveling motor from the discharge port located opposite to the wheel (10, 11) and a second space (SP2) in the speed re- driving device side of the cargo handling motor (as far ducer (22, 23) communicate with each other, and as the above example is concerned, for example, the 55 lubricating oil is enabled to circulate through both the wind discharged from the discharge port 89) can also be first and second spaces (SP1, SP2). positively guided to the wheel driving device side by the duct or the guide plate, whereby the wind discharged 4. The forklift according to Claim 2,

7 13 EP 2 692 686 B1 14

wherein the cargo handling motor (16) is arranged staplers (FL1) so angeordnet ist, dass der between the left and right wheel driving devices (14, Luftstrom, der von dem Auslassanschluss 15) in a left-and-right direction (Y1) of the forklift (88) ausgegeben wird, die Radantriebsvor- (FL1) such that an axial direction (X1) of the cargo richtung (14, 15) erreicht. handling motor (16) is turned to a front-and-rear di- 5 rection (X2) of the forklift (FL1), 2. Gabelstapler nach Anspruch 1, der zwei Radan- wherein the discharge port (88) is provided so that triebsvorrichtungen (14, 15) aufweist, wobei die wind generated by the wind generating mechanism Radantriebsvorrichtungen (14, 15) einzeln an den (W1) is discharged in a radial direction, and linken bzw. rechten Rädern (12, 13) vorgesehen wherein the traveling motor (10, 11) of the wheel 10 sind. driving device (14, 15) includes fins (90A, 91A) that extend along the axial direction thereof. 3. Gabelstapler nach Anspruch 2, wobei jede Radan- triebsvorrichtung (14, 15) ein Drehzahlunterset- 5. The forklift according to Claim 2, zungsgetriebe (22, 23) aufweist, welches mit dem wherein the cargo handling motor (16) is arranged 15 Fahrmotor (10, 11) gekoppelt ist, und such that an axial direction (X1) of the cargo handling wobei ein erster Freiraum (SP1) in dem Fahrmotor motor (16) is turned to a left-and-right direction (Y1) (10, 11) und ein zweiter Freiraum (SP2) in dem Dreh- of the forklift (FL1), zahluntersetzungsgetriebe (22, 23) miteinander in wherein the discharge port (88, 89) is provided so Verbindung stehen, und wobei Schmieröl durch so- that wind generated by the wind generating mecha- 20 wohl den ersten Raum (SP1) als auch den zweiten nism (W1) is discharged in a radial direction, and Raum (SP2) zirkulieren kann. wherein the traveling motor (10, 11) of the wheel driving device (14, 15) includes fins (94A, 95A) that 4. Gabelstapler nach Anspruch 2, extend along in a circumferential direction thereof. wobei der Lastenhandhabungsmotor (16) zwischen 25 den linken und rechten Radantriebsvorrichtungen 6. The forklift according to Claim 2, (14, 15) in einer Links-Rechts-Richtung (Y1) des Ga- wherein the cargo handling motor (16) includes dis- belstaplers (FL1) angeordnet ist, so dass eine axiale charge ports (96, 97) that are arranged at positions Richtung (X1) des Lastenhandhabungsmotors (16) where the distances to the left and right wheel driving zu einer Vorwärts-RückwärtsRichtung (X2) des Ga- devices (14, 15)are different and that discharge wind 30 belstaplers (FL1) gedreht bzw. ausgerichtet ist, wo- toward the wheel driving devices (14, 15), respec- bei der Auslassanschluss (88) so vorgesehen ist, tively. dass ein Luftstrom, der von dem Luftstromerzeu- gungsmechanismus (W1) erzeugt wird, in einer radialen Richtung ausgegeben wird, und Patentansprüche 35 wobei der Fahrmotor (10, 11) der Radantriebsvor- richtung(14, 15) Finnen (90A; 91A)aufweist, diesich 1. Gabelstapler (FL1), der Folgendes aufweist: entlang der axialen Richtung davon erstrecken.

eine Radantriebsvorrichtung (14, 15), die einen 5. Gabelstapler nach Anspruch 2, Fahrmotor (10, 11) aufweist und ein Rad (12, 40 wobei der Lastenhandhabungsmotor (16) so ange- 13) antreibt; und ordnet ist, dass eine axiale Richtung (X1) des Las- eine Lastenhandhabungsvorrichtung (20), die tenhandhabungsmotors (16) zu einer Links-Rechts- einen Lastenhandhabungsmotor (16) aufweist, Richtung (Y1) des Gabelstaplers (FL1) gedreht bzw. und einen Lastenhandhabungsmechanismus ausgerichtet ist, (18) antreibt, 45 wobei der Auslassanschluss (88, 89) so vorgesehen dadurch gekennzeichnet, dass ist, dass ein Luftstrom, der durch den Luftstromer- der Lastenhandhabungsmotor (16) Folgendes zeugungsmechanismus (W1) erzeugt wird, in einer aufweist: radialen Richtung ausgegeben wird, und wobei der Fahrmotor (10, 11) der Radantriebsvor- eine Luftstromerzeugungsmechanismus50 richtung(14, 15) Finnen (94A, 95A)aufweist, diesich (W1), der einen Luftstrom durch die Dre- in einer Umfangsrichtung davon erstrecken. hung einer Motorwelle (84) des Lasten- handhabungsmotors (16) erzeugt; und 6. Gabelstapler nach Anspruch 2, wobei der Lasten- einen Auslassanschluss (88), der den vom handhabungsmotor (16) Auslassanschlüsse (96, Luftstromerzeugungsmechanismus (W1) 55 97) aufweist, die an Positionen angeordnet sind, wo erzeugten Luftstrom auslässt, und die Distanzen zu den linken und rechten Radan- wobei der Lastenhandhabungsmotor (16) triebsvorrichtungen (14, 15) unterschiedlich sind, in einem Fahrzeugkörper (58) des Gabel- und die einen Luftstrom jeweils zu den Radantriebs-

8 15 EP 2 692 686 B1 16

vorrichtungen(14, 15) auslassen. gauche-droite (Y1) du chariot élévateur à fourche (FL1) de sorte qu’une direction axiale (X1) du moteur de manipulation de charge (16) est orientée dans Revendications une direction avant-arrière (X2) du chariot élévateur 5 à fourche (FL1), 1. Chariot à fourche (FL1) comprenant : dans lequel l’orifice de refoulement (88) est prévu de telle sorte de que le flux d’air généré par le mé- un dispositif d’entraînement de roue (14, 15) qui canisme de génération de ventilation (W1) est refou- comprend un moteur de déplacement (10, 11) lé dans une direction radiale, et et entraîne une roue (12, 13) ; et 10 dans lequel le moteur de déplacement (10, 11) du un dispositif de manipulation de charge (20) qui dispositif d’entraînement de roue (14, 15) comprend comprend un moteur de manipulation de charge des ailettes (90A, 91A) qui s’étendent suivant sa di- (16) et entraîne un mécanisme de manipulation rection axiale. de charge (18), caractérisé en ce que : 15 5. Chariot élévateur à fourche selon la revendication 2, dans lequel le moteur de manipulation de charge le moteur de manipulation de charge (16) (16) est agencé de telle sorte qu’une direction axiale comprend : (X1) du moteur de manipulation de charge (16) est orientée dans une direction gauche-droite (Y1) du un mécanisme de génération de venti- 20 chariot élévateur à fourche (FL1), lation (W1) qui génère un flux d’air par dans lequel l’orifice de refoulement (88, 89) est prévu la rotation d’un arbre moteur (84) du de telle sorte que le flux d’air généré par le méca- moteur de manipulation de charge nisme de génération de ventilation (W1) est refoulé (16) ; et dans une direction radiale, et un orifice de refoulement (88) qui refou- 25 dans lequel le moteur de déplacement (10, 11) du le le flux d’air généré par le mécanisme dispositif d’entraînement de roue (14, 15) comprend de génération de ventilation (W1), et des ailettes (94A, 95A) qui s’étendent suivant une direction circonférentielle de celui-ci. dans lequel le moteur de manipulation de charge (16) est agencé dans un corps de 30 6. Chariot élévateur à fourche selon la revendication 2, véhicule (58) du chariot élévateur à fourche dans lequel le moteur de manipulation de charge (FL1) afin que le flux d’air refoulé par l’orifice (16) comprend des orifices de refoulement (96, 97) de refoulement (88) atteigne le dispositif qui sont agencés à des positions où les distances d’entraînement de roue (14, 15). par rapport aux dispositifs d’entraînement de roue 35 gauche et droit (14, 15) sont différentes, et qui re- 2. Chariot élévateur à fourche selon la revendication 1, foulent de l’air en direction du dispositif d’entraîne- comprenant deux dispositifs d’entraînement de roue ment de roue (14, 15), respectivement. (14, 15), dans lequel les dispositifs d’entraînement de roue (14, 15) sont prévus individuellement au niveau des 40 roue gauche et droite (12, 13), respectivement.

3. Chariot élévateur à fourche selon la revendication 2, dans lequel chaque dispositif d’entraînement de roue (14, 15) comprend un réducteur de vitesse (22, 45 23) qui est couplé au moteur de déplacement (10, 11), et dans lequel un premier espace (SP1) dans le moteur de déplacement (10, 11) et un deuxième espace (SP2) dans le réducteur de vitesse (22, 23) commu- 50 niquent entre eux, et de l’huile de lubrification peut circuler à la fois dans le premier et dans le deuxième espace (SP1, SP2).

4. Chariot élévateur à fourche selon la revendication 2, 55 dans lequel le moteur de manipulation de charge (16) est agencé entre les dispositifs d’entraînement de roue gauche et droit (14, 15) dans une direction

9 EP 2 692 686 B1

10 EP 2 692 686 B1

11 EP 2 692 686 B1

12 EP 2 692 686 B1

13 EP 2 692 686 B1

14 EP 2 692 686 B1

15 EP 2 692 686 B1

16 EP 2 692 686 B1

17 EP 2 692 686 B1

REFERENCES CITED IN THE DESCRIPTION

This list of references cited by the applicant is for the reader’s convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description

• JP 2004122916 A [0008] • US 5558174 A [0010] • JP 2004260969 A [0009]