JP5276573B2 - Final reduction device for work vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten the size especially in a rotation axial direction in a final reduction gear of a working vehicle. <P>SOLUTION: The final reduction gear 4 reduces and transmits the rotation input from a motor to front wheels, and includes: a transfer reduction gear 20; a planetary gear mechanism 21; and a brake mechanism 22. The transfer reduction gear 20 includes: an input shaft 28 and output shaft 29; a drive gear 30 arranged coaxially with the input shaft 28; and a driven gear 31 arranged coaxially with the output shaft 29, and meshed with the drive gear 30, and reduces the rotation from the motor. The planetary gear mechanism 21 is arrange coaxially with the output shaft 29, and further reduces the output rotation from the transfer reduction gear 20 to transmit to the front wheels. The brake mechanism 22 is arranged by being offset from the output shaft 29, and puts a brake on the rotation of the output shaft 29. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a final reduction device, and more particularly to a final reduction device for a working vehicle that decelerates rotation input from a drive source and transmits the reduced rotation to drive wheels.

  For example, a forklift as a working vehicle has left and right final drive devices as disclosed in Patent Document 1. Each final drive device is housed in left and right drive cases fixed to the vehicle body, and includes a motor having a motor shaft, and a final reduction device that decelerates rotation of the motor and transmits it to a wheel fixed to the hub. Have. The final reduction gear includes a drive gear and a driven gear that reduce the rotation of the motor, and a planetary gear reducer that further reduces the rotation of the driven gear. A wet brake device is provided inside the driven gear.

  In this final drive device, the rotation from the motor is decelerated by the drive gear and the driven gear, and further decelerated by the planetary gear mechanism and transmitted to the wheel. When stopping, the driven gear is braked by the wet brake device.

  Further, Patent Documents 2 and 3 also show drive units for forklifts. Similarly to Patent Document 1, the final reduction device shown in these documents is a reduction device using a drive gear and a driven gear. And a planetary gear reducer that further reduces the rotation output from the reducer.

International Publication No. 2007/119577 International Publication No. 2005/005167 JP 2009-83796 A

  In particular, in a forklift, a member such as a mast for moving the fork up and down is disposed on the front side inside the tire. For this reason, as shown in Patent Documents 1 to 3, the motor is disposed behind the output shaft, which is the rotation shaft of the tire, and the brake device is disposed coaxially with the output shaft. The brake device is disposed on the inner periphery of the drive gear.

  However, such a configuration requires a large space between the motor and the tire, and the vehicle cannot be made compact in the left-right direction (width direction). In addition, since the motor is disposed relatively inside the vehicle body, the space inside the vehicle body is reduced.

  In the conventional final reduction gear, the planetary gear speed reducer has a large reduction ratio. However, a reduction gear composed of a drive gear and a driven gear must also have a large reduction ratio. For this reason, the driven gear has a large diameter, which hinders downsizing.

  SUMMARY OF THE INVENTION An object of the present invention is to achieve downsizing particularly in the direction of the rotation axis in a final reduction device for a working vehicle.

A final reduction device for a working vehicle according to a first aspect of the invention is a device for reducing rotation input from a drive source and transmitting the reduced rotation to a drive wheel, comprising: a transfer reduction gear, a planetary gear mechanism, and a brake mechanism. I have. The transfer speed reducer has an input shaft and an output shaft, a drive gear arranged coaxially with the input shaft, and a driven gear arranged coaxially with the output shaft and meshing with the drive gear, and decelerates rotation from the drive source. To do. The planetary gear mechanism is arranged coaxially with the output shaft, and a first planetary gear speed reducer that decelerates the rotation of the output shaft, and a second planetary gear that further reduces the output rotation of the first planetary gear speed reducer and transmits it to the drive wheels. A gear reducer, and further decelerates the output rotation from the transfer reducer and transmits it to the drive wheels. The brake mechanism includes a brake shaft disposed offset from the input shaft and the output shaft, and a brake gear that is provided on the brake shaft and meshes with a driven gear, and brakes rotation of the output shaft.

  In this device, the rotation from the drive source is decelerated by the transfer speed reducer, further decelerated by the planetary gear mechanism, and transmitted to the drive wheels. The rotation of the output shaft is braked by the brake mechanism.

  Here, particularly in a forklift driven by an electric motor, a capacitor may be employed as in a hybrid vehicle or the like in order to further improve the performance of the forklift. This capacitor can store regenerative energy from the load. In such a vehicle, in order to accumulate regenerative energy during braking, this regenerative energy accumulation action acts as a brake. Therefore, since the brake capacity of a normal brake mechanism can be reduced, the diameter of a member such as a brake disk included in the brake mechanism can be reduced, and the entire brake mechanism can be made compact. In such a situation, even if the brake mechanism is offset from the output shaft and disposed forward (opposite to the input shaft with respect to the output shaft), interference with other components can be avoided.

  Therefore, in the device according to the first aspect of the invention, the brake mechanism that is arranged coaxially with the output shaft in the conventional device is arranged offset from the output shaft. For this reason, components, such as a motor, can be arrange | positioned in the space where the brake mechanism was arrange | positioned with the conventional apparatus, and the dimension of the rotating shaft direction of the whole final reduction gear apparatus becomes compact.

Even when the drive source is other than a motor or the work vehicle is other than a forklift, the brake mechanism in the final reduction gear is offset from the output shaft, so that the entire length of the final reduction gear in the direction of the rotation axis can be obtained. Ru it is possible to shorten the of.

In here, particularly when using a motor as a driving source, in order to reduce the size of the motor, it is necessary to mount a high-rotation type a and the low torque capacity motor. When such a high-rotation type motor is used, the rotation must be decelerated with a large reduction ratio until the drive wheel which is the final output.

Therefore, in the apparatus according to the present invention, the planetary gear mechanism is constituted by two planetary gear reducers to constitute a reduction mechanism having a large reduction ratio. In addition, by configuring the planetary gear mechanism with two planetary gear speed reducers and using a speed reduction mechanism with a large speed reduction ratio, the speed reduction ratio of the transfer speed reducer can be reduced as compared with the prior art. For this reason, the diameter of the driven gear of the transfer speed reducer can be reduced to make the radial dimension compact. Therefore, when the driving wheel is for example configured in the tire and the hole, it is possible to ing to place the entire device, including the transfer reduction gear and the planetary gear mechanism to the wheel.

A final reduction device for a working vehicle according to a second invention is the device according to the first invention, wherein the drive wheel is a tire and a wheel fitted with the tire, and the transfer reduction device and the planetary gear mechanism are arranged at the inner periphery of the wheel. It is arrange | positioned in the width | variety of the rotating shaft direction.

  Here, since the transfer speed reducer and the planetary gear mechanism are disposed in the wheel, the size of the entire apparatus in the direction of the rotation axis is further shortened.

Final reduction gear of the work vehicle according to the third invention, in the apparatus of the first invention, the brake mechanism comprises at least one disc-shaped brake disk fixed to the brake shaft, the brake disc is pressed against And a brake main body having a fixing portion.

A final reduction device for a working vehicle according to a fourth aspect of the present invention is the device of the first aspect , wherein the drive source is an electric motor, and the output shaft of the electric motor is arranged coaxially with the input shaft.

  In the present invention as described above, the dimension in the direction of the rotation axis of the final reduction gear of the work vehicle can be made compact. For this reason, a wide space can be secured inside the vehicle body, and in particular, in a forklift driven by an electric motor, the electrical components can be easily arranged.

1 is a partial plan view of a forklift having a final reduction gear according to an embodiment of the present invention. FIG. 3 is a developed sectional view of the final reduction gear. FIG. 3 is a developed sectional view of a transfer speed reducer of the final speed reducer. FIG. 3 is a developed sectional view of a planetary gear mechanism of the final reduction gear. FIG. 3 is a developed sectional view of a brake mechanism of the final reduction gear. FIG. 3 is a developed sectional view showing a lubricating structure of the final reduction gear. The Z direction arrow directional view of FIG. The figure equivalent to FIG. 7 of other embodiment of a lubrication structure. The cross-sectional expanded view of other embodiment of the lubrication structure. Sectional drawing which shows the structure for lubricating the needle bearing of a planetary gear. Sectional drawing which shows another structure for lubricating the needle bearing of a planetary gear. Sectional drawing which shows another structure for lubricating the needle bearing of a planetary gear.

  1 and 2 show a cross-sectional configuration of a forklift having a final reduction gear and a final reduction gear according to an embodiment of the present invention. FIG. 2 shows an expanded cross-sectional configuration, and the positional relationship between the upper, lower, left, and right of each member is expressed differently from the actual positional relationship. In FIG. 2, only one final reduction gear is shown, but a similar device is also arranged on the other side.

  As shown in FIG. 1, the forklift has a final drive device 2 for driving the left and right front wheels 1. The final drive device 2 includes an electric motor 3 and a final reduction device 4 that decelerates the rotation of the motor 3 and transmits it to the front wheels 1. The forklift has a pair of forks 5 on the inner side of the front wheel 1 on the front side of the front wheel 1, and a mast 6 is disposed on the base end side of the fork 5 in the vicinity of the front wheel 1. ing.

  The motor 3 is disposed on the vehicle inner side of the front wheel 1 so as to be offset rearward from the axle center C in order to avoid interference with the mast 6. The final reduction gear 4 is arranged such that the center in the front-rear direction coincides with the axle center C. Further, the final reduction gear 4 is arranged so that most of it falls within the width of the front wheel 1 in the direction of the rotation axis of the wheel 7.

[motor]
The motor 3 is disposed inside the vehicle body. As shown in FIG. 2, a motor shaft 10 that is an output shaft of the motor 3 is rotatably supported by a support member 12 by a ball bearing 11. A spline hole 10 a is formed at the center of the motor shaft 10. Here, in order to reduce the size of the motor 3, the motor 3 used in the present embodiment is mounted with a high-rotation type motor that rotates at a high rotational speed and has a low torque capacity.

[Final decelerator]
The final reduction gear 4 includes a fixed housing 14 and a case 18 including a main housing 15, an end housing 16, and an end cover 17. The final reduction gear 4 includes a transfer speed reducer 20 whose input shaft is arranged coaxially with the motor shaft 10, a planetary gear mechanism 21 arranged parallel to the motor shaft 10 and coaxially with the axle center of the front wheel 1, 1 and a brake mechanism 22 for braking 1. The transfer speed reducer 20, the planetary gear mechanism 21, and the brake mechanism 22 are housed inside the case 18.

  In such a final reduction gear 4, as described above, the case 18 that houses the transfer reduction gear 20 and the planetary gear mechanism 21 is within the width of the wheel 7 in the rotational axis direction inside the wheel 7 of the front wheel 1. Arranged to fit.

<Case>
The fixed housing 14 is fixed to the vehicle body frame. The fixed housing 14 is formed with an input shaft opening 14a, an output shaft opening 14b, and a brake shaft opening 14c penetrating in the rotation axis direction (hereinafter simply referred to as the axial direction). The fixed housing 14 is formed with a brake accommodating portion 14d coaxially with the brake shaft opening 14c. The brake accommodating portion 14d has a larger diameter than the brake shaft opening 14c and is formed to be open on the inner surface of the fixed housing 14 in the vehicle body.

  The main housing 15 is formed in a cylindrical shape and is disposed outside the vehicle body of the fixed housing 14. The end housing 16 is formed in a cylindrical shape and has a fixing flange 16a on the outer peripheral side. The flange 16 a is fixed to the main housing 15 by a bolt 25 together with the wheel 7 of the front wheel 1. The end cover 17 is a plate-like member, and the outer peripheral portion is fixed to the end housing 16 by a plurality of bolts 26.

  A case 18 including a main housing 15, an end housing 16, and an end cover 17 is rotatable with respect to the fixed housing 14. An oil seal 24 is provided between the main housing 15 and the fixed housing 14 in order to prevent oil inside the case 18 from leaking out.

<Transfer reducer>
As shown in FIG. 3, the transfer speed reducer 20 has an input shaft 28, an output shaft 29, a drive gear 30, and a driven gear 31. In this embodiment, the drive gear 30 and the driven gear 31 are helical gears, but may be formed by spur gears.

  The input shaft 28 is disposed coaxially with the motor shaft 10. A spline shaft 28 a is formed at the tip (end on the motor side) of the input shaft 28, and the spline shaft 28 a is engaged with a spline hole 10 a formed in the motor shaft 10. The input shaft 28 is rotatably supported by the fixed housing 14 and the main housing 15 (directly described below as a second carrier) via a pair of ball bearings 32 and 33. A drive gear 30 is formed integrally with the input shaft 28.

  The driven gear 31 meshes with the drive gear 30 and is rotatably supported by the fixed housing 14 and the main housing 15 (directly described later second carrier) via a pair of ball bearings 34 and 35. . A spline hole 31 a is formed at the center of the driven gear 31. An output shaft 29 passes through the center of the driven gear 31, and a spline shaft 29 a formed on the output shaft 29 is engaged with a spline hole 31 a of the driven gear 31. The output shaft 29 is coaxial with the axle center of the front wheel 1 and is disposed in parallel with the input shaft 28.

<Planetary gear mechanism>
As shown in FIG. 4, the planetary gear mechanism 21 is disposed coaxially with the output shaft 29, and further reduces the output rotation of the first planetary gear speed reducer 38 and the first planetary gear speed reducer 39. And a second planetary gear reducer 39 in the second stage.

-First planetary gear reducer-
The first planetary gear speed reducer 38 in the first stage includes a first sun gear 40, a plurality of first planetary gears 41, a first carrier 42 that rotatably supports the plurality of planetary gears 41, and a first ring gear. 43.

  The first sun gear 40 is formed integrally with the output shaft 29 at the tip of the output shaft 29 (end on the outside of the vehicle body). A ball 44 for receiving a thrust force acting on the output shaft 29 is provided between the tip of the output shaft 29 and the end cover 17.

  The plurality of first planetary gears 41 mesh with the first sun gear 40 and the first ring gear 43. The plurality of first planetary gears 41 are rotatably supported by a support pin 45 fixed to the first carrier 42 via a needle bearing 46. A thrust washer 47 is disposed between both side surfaces of each first planetary gear 41 and the first carrier 42.

  The first carrier 42 is formed in a cylindrical shape, and slits penetrating in the radial direction are formed at a plurality of locations in the circumferential direction. As described above, the first planetary gear 41 is supported by the slit via the support pin 45. A cylindrical portion 42a protruding in the axial direction is formed on the inner peripheral portion of the first carrier 42 on the right side surface on the inner side of the vehicle body in FIG. A connecting ring gear 42b is formed on the inner surface of the protrusion 42a. A thrust washer 48 is provided between the inner periphery of the first carrier 42 on the left side surface in FIG. 4 and the end cover 17.

  The first ring gear 43 is formed integrally with the end housing 16 on the inner peripheral surface of the end housing 16.

-Second planetary gear reducer-
The second stage planetary gear speed reducer 39 in the second stage rotatably supports the first sun gear 50, a plurality (four in this embodiment) of second planetary gears 51, and a plurality of second planetary gears 51. A second carrier 52 and a second ring gear 53 are included.

  The 2nd sun gear 50 has the hole 50a penetrated to an axial direction in the center part, and the output shaft 29 has penetrated this hole 50a. The connection ring gear 42b of the first carrier 42 meshes with one end side (the left side in FIG. 4) of the second sun gear 50. Due to this meshing, rotation of the first carrier 42 of the first planetary gear speed reducer 38 is input to the second sun gear 50.

  The plurality of second planetary gears 51 mesh with the other end side of the second sun gear 50 (the right side in FIG. 4) and the second ring gear 53. The plurality of second planetary gears 51 are rotatably supported by a support pin 55 fixed to the second carrier 52 via a needle bearing 56.

  The second carrier 52 is fixed to the fixed housing 14 by a plurality of bolts 57 attached from the inside to the outside of the vehicle body. Similar to the first carrier 42, the second carrier 52 is formed in a cylindrical shape, and slits penetrating in the radial direction are formed at a plurality of locations in the circumferential direction. The second planetary gear 51 is supported by the slit via a support pin 55. Thrust washers 58 are disposed between the side surfaces of each planetary gear 51 and the second carrier 52.

  The second carrier 52 has a large-diameter portion 52a on the inner side of the vehicle body and a small-diameter portion 52b on the outer side of the vehicle body with a portion supporting the second planetary gear 51 interposed therebetween. Tapered roller bearings 59 and 60 are mounted on the large diameter portion 52 a and the small diameter portion 52 b, respectively, and the case 18 including the main housing 15 can be freely rotated by the second carrier 52 via the tapered roller bearings 59 and 60. It is supported. As described above, the two tapered roller bearings 59 and 60 are arranged with the second planetary gear 51 interposed therebetween, and are arranged so as to be distributed on the inner side and the outer side of the center Ct of the front wheel 1. The tapered roller bearing 60 disposed outside the vehicle body has a smaller diameter than the tapered roller bearing 59 disposed inside the vehicle body. A plurality of bolts 25 for fixing the wheel 7 and the end housing 16 to the main housing 15 are disposed on the outer peripheral side of the tapered roller bearing 60. The two taper roller bearings 59 and 60 are substantially the same in terms of bearing capacity.

  A gear storage opening 52c and three bearing storage openings 52d, 52e, and 52f are formed on the inner surface of the second carrier 52 on the vehicle body. Drive gear 30 and driven gear 31 are housed in gear housing opening 52c, and ball bearing 33 that supports input shaft 28 and ball bearing 35 that supports output shaft 29 are mounted in bearing housing openings 52d and 52e, respectively. Has been. The end surface on the inner side of the vehicle body of the second carrier 52 and the end surface on the outer side of the vehicle body of the fixed housing 14 are fixed.

  A support plate 61 for fixing the tapered roller bearing 60 to the main housing 15 is fixed to the end surface of the second carrier 52 outside the vehicle body by a plurality of bolts 62.

  The second ring gear 53 is formed integrally with the main housing 15 on the inner peripheral surface of the main housing 15.

[Brake mechanism]
As shown in FIG. 5, the brake mechanism 22 includes a brake shaft 65, a brake gear 66, and a brake main body 67.

  The brake shaft 65 is arranged in parallel with the output shaft 29 and offset from the output shaft 29, and a spline shaft 65a is formed at the tip on the inner side of the vehicle. The brake shaft 65 is rotatably supported by the fixed housing 14 and the second carrier 52 via a pair of ball bearings 70 and 71. The ball bearing 71 is mounted in the bearing housing opening 52 f of the second carrier 52. A brake gear 66 is formed integrally with the brake shaft 65 on the brake shaft 65. The brake gear 66 meshes with the driven gear 31 of the transfer speed reducer 20. The brake gear 66 is a helical gear in this embodiment, but may be formed of a spur gear.

  The brake main body 67 has two brake disks 74, three fixing plates 75, and a piston 76.

  The brake disc 74 is a ring-shaped plate and has a spline hole 74a on the inner periphery. The spline hole 74 a is engaged with the spline shaft 65 a of the brake shaft 65. Therefore, the brake disc 74 is not rotatable relative to the brake shaft 65 and is movable in the axial direction. Further, friction facings are mounted on both surfaces of the brake disc 74.

  The fixed plate 75 is a ring-shaped plate and is disposed so as to sandwich the two brake disks 74. One protrusion is formed on the outer periphery of the fixed plate 75, and a notch is formed in the protrusion. A pin provided in the brake accommodating portion 14 d of the fixed housing 14 is engaged with the notch of the fixed plate 75. Thus, the fixed plate 75 is not rotatable relative to the fixed housing 14 and is movable in the axial direction.

  The piston 76 is a disk-shaped member, and an operation portion 76a is provided at the center. By pushing the operating portion 76a toward the brake shaft 65 by an external operation, the brake disc 74 and the fixed plate 75 are pressed against each other, and the brake shaft 65 is braked. By braking the brake shaft 65, the rotation of the output shaft 29, the planetary gear mechanism 21, and the front wheel 1 is braked.

  A brake cover 78 is provided inside the vehicle body of the brake main body 67. The brake cover 78 is fixed to the fixed housing 14 by a plurality of bolts 79. With such a configuration, the brake main body 67 is sealed inside the case 18 together with the oil.

[Lubrication structure]
Next, the lubrication structure of the needle bearing 56 that supports the second planetary gear 51 will be described with reference to FIGS. 6 and 7. FIG. 7 is a view in the direction of the arrow Z in FIG. 6 and shows the second carrier 52 with the fixed housing 14 removed.

  Generally, in the final reduction gear 4, lubricating oil is accumulated up to a height indicated by a straight line OL in FIG. In the conventional apparatus, the region above the oil level OL is expected to be lubricated in the atmosphere by oil scattering, or forced lubrication using an oil passage such as an oil supply pipe is performed.

  Here, in the configuration of the present embodiment, as described above, the second carrier 52 is fixed to the fixed housing 14 and does not revolve. Therefore, it is difficult for lubricating oil to be supplied to the needle bearings 56 that support the two second planetary gears 51 disposed above the four second planetary gears 51. Therefore, there is a possibility that the lubrication is insufficient in the atmospheric lubrication, and the configuration is complicated in the case of the forced lubrication.

  Therefore, in this embodiment, the gear pump action of the drive gear 30 and the driven gear 31 of the transfer speed reducer 20 and the brake gear 66 of the brake mechanism 22 is used to securely connect the needle bearing 56 that supports the second planetary gear 51. Oil for lubrication is supplied. Hereinafter, this lubricating structure will be described in detail.

  First, in this embodiment, the input shaft 28, the output shaft 29, and the brake shaft 65, that is, the gears 30, 31, 66 are arranged as shown in FIG. That is, the drive gear 30, the driven gear 31, and the brake gear 66 are arranged in a straight line, the drive gear 30 is disposed at the lowermost position, and the brake gear 66 is disposed at the uppermost position. This is to suppress loss due to the brake mechanism 22. Specifically, when the brake disk 74 is immersed in oil, the oil is agitated by the rotation of the brake disk 74. At this time, if the area where the brake disc 74 is immersed in the oil is large, the resistance due to oil agitation is so much that this resistance is lost. Therefore, in order to suppress the loss, the brake mechanism 22 is disposed above so that the brake disc 74 is in contact with the oil with a minimum amount.

  As described above, the gear carrier opening 52c is formed on the side surface of the second carrier 52 on the vehicle body inner side. On the other hand, the fixed housing 14 is fixed to an end surface of the second carrier 52 on the inner side of the vehicle body. The fixed housing 14 has three openings 14a, 14b, and 14c, but the other portions are closed. Therefore, a substantially closed gear storage space Gr formed by the gear storage opening 52c is formed between the portion of the second carrier 52 inside the vehicle body and the fixed housing 14. This gear storage space Gr is shown by a broken line in FIG. 6 and FIG.

  On the other hand, in the second carrier 52, a lower oil reservoir 82 is provided below the gear storage space Gr, and an upper oil reservoir 83 is provided above the gear storage space Gr. Each of the oil reservoirs 82 and 83 is formed on the side surface on the inner side of the vehicle body of the second carrier 52, and is a portion recessed from the end surface 52 g attached to the fixed housing 14.

  The lower oil reservoir 82 includes a first reservoir portion 82a positioned below the meshing portion between the drive gear 30 and the driven gear 31, and a second reservoir portion 82b positioned below the meshing portion between the driven gear 31 and the brake gear 66. And a connecting portion 82c positioned between them. Further, a suction port 82d is continuously formed in the first reservoir 82a from below. This suction port 82d also appears in FIG.

  Each of the four support pins 55 fixed to the second carrier 52 is formed with a lateral oil passage 55a and a vertical oil passage 55b for lubrication. The lateral oil passage 55a is formed at the center of the support pin 55 along the axial direction. Further, the vertical oil passage 55b is formed so as to communicate from the outer peripheral surface of the support pin 55 to the horizontal oil passage 55a. The lateral oil passage 55a of the support pin 55 that supports the two planetary gears 51 disposed below communicates with the first reservoir portion 82a and the second reservoir portion 82b of the lower oil reservoir 82.

  The upper oil reservoir 83 includes a third reservoir 83a positioned above the meshing portion of the drive gear 30 and the driven gear 31, and a fourth reservoir 83b positioned above the meshing portion of the driven gear 31 and the brake gear 66. And a connecting portion 83c positioned between them. The third reservoir portion 83a and the fourth reservoir portion 83b are respectively formed continuously from the oil discharge port from the gear storage space Gr.

  Similarly to the case of the two lower planetary gears 51, the lateral oil passage 55 a of the support pin 55 that supports the two planetary gears 51 arranged on the upper side is connected to the third reservoir 83 a of the upper oil reservoir 83 and the 4 communicates with the reservoir 83b.

[Operation]
In the final reduction gear 4 configured as described above, when rotation is input from the motor 3, this rotation is decelerated by the drive gear 30 and the driven gear 31 of the transfer reduction gear 20 and output to the output shaft 29. The rotation of the output shaft 29 is transmitted to the front wheel 1 via the first sun gear 40, the first planetary gear 41, and the first ring gear 43 of the first planetary gear speed reducer 38. Further, the output of the first carrier 42 of the first planetary gear speed reducer 38 is transmitted to the second sun gear 50 of the second planetary gear speed reducer 39, and the second sun gear 50, the second planetary gear 51, and the second ring. It is transmitted to the front wheel 1 through the gear 53.

  As described above, the rotation of the motor 3 is decelerated at a reduction ratio determined by the transfer speed reducer 20 and the planetary gear mechanism 21 including the first and second planetary gear speed reducers 38 and 39 and transmitted to the front wheel 1. Is done.

  Further, when a brake operation is performed from the outside, the piston 76 of the brake mechanism 22 presses the brake disc 74 and the fixed plate 75 together. Thereby, the rotation of the brake shaft 65 is braked, and the rotation of the driven gear 31 that meshes with the brake gear 66 of the brake shaft 65, that is, the rotation of the output shaft 29 is braked.

  During the operation as described above, the drive gear 30, the driven gear 31, and the brake gear 66 are always rotating. Each gear 30, 31, 66 rotates in both directions according to the traveling direction. By the rotation of these gears 30, 31, 66, the oil accumulated in the case 18 is filled into the first reservoir portion 82a and the second reservoir portion 82b of the lower oil reservoir 82 through the suction port 82d. The first oil reservoir 82a and the second oil reservoir 82b communicate with a lateral oil passage 55a of a support pin 55 that supports the second planetary gear 51 disposed below. Accordingly, the oil accumulated in the pool portions 82a and 82b is supplied to the needle bearing 56 provided on the outer periphery of the support pin 55 via the horizontal oil passage 55a and the vertical oil passage 55b.

  The oil sucked into the lower oil reservoir 82 is filled in the gear storage space Gr and further discharged into the upper oil reservoir 83 through the discharge port. The oil discharged to the upper oil reservoir 83 is filled in the third reservoir 83a and the fourth reservoir 83b, and the support pin 55 that supports the second planetary gear 51 disposed above is filled in the same manner as described above. It is supplied to the needle bearing 56 that supports the second planetary gear 51 via the horizontal oil passage 55a and the vertical oil passage 55b.

[Feature]
(1) Since a brake by a load for accumulating regenerative energy acts during a brake operation, the brake mechanism 22 can be reduced in size, and therefore the brake mechanism 22 can be offset from the output shaft 29 and disposed. Thereby, some or all of the parts constituting the motor 3 and the transfer speed reducer 20 can be arranged in the space where the brake mechanism is arranged in the conventional apparatus. Therefore, the axial dimension of the entire final reduction gear 4 can be made compact. Further, since the motor 3 can be arranged outside the vehicle body as compared with the conventional device, a wider space can be secured inside the vehicle body, and a large electrical component can be arranged in this space.

  (2) Since the planetary gear mechanism 21 includes the first and second planetary gear speed reducers 38 and 39, the planetary gear mechanism 21 can reduce the rotation with a very large reduction ratio. For this reason, the reduction ratio of the transfer speed reducer 20 can be made smaller than before, and the diameter of the driven gear 31 of the transfer speed reducer 20 can be made smaller. Therefore, the periphery of the output shaft 29 to which the driven gear 31 is attached can be made compact.

  (3) The transfer speed reducer 20 and the planetary gear mechanism 21 can be arranged inside the wheel, and the space occupied by the final reduction gear 4 becomes compact.

  (4) Since the oil is supplied to the needle bearing 56 that supports the second planetary gear 51 using the gear pump action of the gears 30 and 31 of the transfer reduction gear 20 and the brake gear 66, a simple configuration is provided. Can reliably supply lubricating oil.

[Other Embodiments]
The present invention is not limited to the above-described embodiments, and various changes or modifications can be made without departing from the scope of the present invention.

  (A) In the above embodiment, the electric motor has been described as an example of the drive source. However, the present invention can be similarly applied to other drive sources such as an engine.

  (B) In the above embodiment, the planetary gear mechanism is configured by the first and second planetary gear speed reducers. However, the planetary gear mechanism may be configured by one planetary gear speed reducer.

  (C) The lubrication structure is not limited to the above embodiment. Another example is shown in FIG. In the example shown in FIG. 8, the upper oil sump formed above the gear storage space Gr is different from the embodiment shown in FIG. Other configurations are the same as those in FIG.

  The upper oil reservoir 93 shown in FIG. 8 is formed on the side surface on the vehicle inner side of the second carrier 52, as in the above-described embodiment, and is a portion that is recessed from the end surface 52 g attached to the fixed housing 14. The upper oil reservoir 93 includes a third reservoir 93a that communicates with the lateral oil passage 55a of the support pin 55 that supports one of the upper two second planetary gears 51, and a lateral oil passage of the other support pin 55. It has the 4th accumulation part 93b connected to 55a, and the connection part 93c located among these. And the discharge port 93d which connects this connection part 93c and the gear accommodation space Gr is formed in the intermediate part of the longitudinal direction of the connection part 93c.

  In the embodiment shown in FIG. 8, the oil filled in the gear storage space Gr is supplied from the discharge port 93d to the pool portions 93a and 93b via the connecting portion 93c, and further, the horizontal oil passage 55a and the vertical oil passage 55b. Are supplied to each needle bearing 56.

  (D) FIG. 9 shows another example of the lubricating structure. The embodiment shown in FIG. 9 lubricates the bearing that supports the motor by utilizing the lubrication structure of the embodiment of FIGS.

  In a conventional final drive device, a grease-enclosed type bearing is used as a bearing that supports the rotation of the motor. In the conventional apparatus, since the rotation speed of the motor is relatively slow, there is no particular problem by using such a grease-enclosed type bearing, and forced lubrication from the outside is unnecessary.

  However, in order to improve the efficiency and reduce the size of the motor, it is necessary to use a motor that can rotate at a high rotational speed. When a high-rotation type motor is used as in this embodiment, if the motor is supported by a grease-enclosed type bearing, the lubrication of the bearing may be insufficient.

  Therefore, forced lubrication with oil is required for the bearing that supports the motor. In order to perform such forced lubrication, an oil pump, an oil pan, and the like are required, resulting in an increase in cost and a difficulty in equipment layout.

  Therefore, in the embodiment shown in FIG. 9, the lubricating oil is forcedly applied to the bearing supporting the motor 3 by using the gear pump action using the gears 30, 31, 66 shown in FIGS. Supply. Hereinafter, a specific configuration will be described.

  First, the motor 3 is supported on the body frame and the motor housing 97 by a pair of ball bearings 95 and 96 at both ends of the motor shaft 10. Further, the input shaft 28 in which the drive gear 30 is formed is formed with a lateral oil passage 28b penetrating in the axial direction at the center. On the other hand, the motor shaft 10 is similarly formed with a lateral oil passage 10b in the central portion along the axial direction. The end of the side oil passage 10 b on the input shaft 28 side communicates with the outside, and communicates with a side oil passage 28 b formed on the input shaft 28. Further, the opposite end of the horizontal oil passage 10b is closed. Further, in the vicinity of the bearings 95 and 96, vertical oil passages 10c, 10d, and 10e that are communicated with the lateral oil passage 10b from the outer peripheral surface of the motor shaft 10 are formed. The space between the vehicle inner end of the motor shaft 10 and the motor housing 97 and the bottom of the case 18 of the final reduction gear 4 are communicated by an external pipe 98.

  In such a configuration, the oil pumped from the bottom of the case 18 by the gear pump action shown in FIG. 7 or FIG. 8 is first filled in the gear storage space Gr, and the oil charged in the gear storage space Gr is The oil is guided to the lateral oil passage 28b of the input shaft 28 through the pool portion. Then, the oil in the horizontal oil passage 28b is guided to the horizontal oil passage 10b of the motor shaft 10, supplied to the ball bearing 95 through the respective vertical oil passages 10c and 10d, and through another vertical oil passage 10e. To the ball bearing 96. And the oil which lubricated each part is returned to the bottom part of case 8 through the external piping 98. FIG.

  In such an embodiment, the bearing that supports the motor 3 is lubricated by using the gear pump action of each gear 30, 31, 66 without using a special oil pump. For this reason, the bearing can be reliably lubricated with an inexpensive configuration.

  (E-1) In the first planetary gear speed reducer 38, the first carrier 42 revolves. Accordingly, the plurality of first planetary gears 41 provided on the first carrier 42 are all immersed in the oil accumulated at the bottom of the case 8. For this reason, oil is supplied also to the needle bearing 46 that supports the first planetary gear 41.

  However, in each of the above embodiments, a high rotation / low torque type motor is used, and the reduction ratio in the transfer speed reducer 20 is relatively small. Therefore, the first planetary gear speed reducer 38 in the first stage is relatively high. The rotation speed is input. Therefore, it is necessary to supply sufficient lubricating oil to the needle bearing 46 that supports the first planetary gear 41. Further, since the needle bearing 46 is surrounded by the first planetary gear 41 and the thrust washer 47, it is difficult for oil to be supplied to the needle bearing 46. Furthermore, in order to avoid a loss when the oil is agitated, there is a demand for lowering the oil level, and there is a demand for improvement in the configuration for supplying oil to the needle bearing 46.

  FIG. 10 shows a configuration for supplying sufficient lubricating oil to the needle bearing 46 that supports the first planetary gear 41.

  FIG. 10 shows a state where one of the plurality of first planetary gears 41 is located at the lowest position. As shown in this figure, the oil level OL in the case 18 is located above the rotation center axis C of the lowest first planetary gear 41.

  The support pin 45 that supports the first planetary gear 41 includes a lateral oil passage 45a formed along the axial direction so as to coincide with the rotation center axis C, and from the outer peripheral surface of the support pin 45 to the lateral oil passage 45a. A communicating vertical oil passage 45b is formed.

  According to such a configuration, when the support pin 45 is submerged in the oil accumulated at the bottom of the case 18, the oil is reliably guided to the needle bearing 46 through the horizontal oil passage 45 a and the vertical oil passage 45 b. For this reason, insufficient lubrication of the needle bearing 46 can be prevented.

  (E-2) FIG. 11 shows a modification of the embodiment shown in FIG. In this example, the lateral oil passage 145a of the support pin 145 is formed eccentrically from the rotation center axis C to the outer peripheral side. The vertical oil passage 145b has the same configuration as the example of FIG.

  In this case, since the support pin 145 is fixed to the first carrier 42 and the lateral oil passage 145a is formed eccentrically on the outer peripheral side, the lateral oil passage is compared with the example of FIG. The time that 145a is immersed in the oil increases. For this reason, the amount of oil supplied to the needle bearing 46 can be increased.

  (E-3) FIG. 12 shows a further modification of the embodiment shown in FIG. In this example, the lateral oil passage 245a of the support pin 245 is formed obliquely with respect to the rotation center axis C. That is, the open end (the right end in FIG. 12) of the horizontal oil passage 245a is located on the inner peripheral side, and the distal end side is located on the outer peripheral side. The vertical oil passage 245b has the same configuration as the example of FIG.

  In this case, the amount of oil supplied to the needle bearing 46 can be increased using gravity and centrifugal force.

DESCRIPTION OF SYMBOLS 1 Front wheel 2 Final drive device 3 Motor 4 Final reduction device 20 Transfer reduction device 21 Planetary gear mechanism 22 Brake mechanism 28 Input shaft 29 Output shaft 30 Drive gear 31 Driven gear 38 First planetary gear reduction device 39 Second planetary gear reduction device 65 Brake shaft 66 Brake gear 67 Brake body 74 Brake disc 75 Fixing plate

Claims (4)

A final deceleration device for a working vehicle that decelerates the rotation input from the drive source and transmits it to the drive wheels,
An input shaft and an output shaft, a drive gear arranged coaxially with the input shaft, and a driven gear arranged coaxially with the output shaft and meshing with the drive gear, and reduce the rotation from the drive source A transfer reducer,
A first planetary gear reducer that is arranged coaxially with the output shaft and decelerates the rotation of the output shaft, and a second planetary gear that further decelerates the output rotation of the first planetary gear reducer and transmits it to the drive wheel. It includes a reduction gear, and a planetary gear mechanism for transmitting the drive wheel and further reduces the rotation output from the transfer speed reducer,
A brake mechanism arranged to be offset from the input shaft and the output shaft, and a brake gear that is provided on the brake shaft and meshes with the driven gear, and brakes the rotation of the output shaft;
A final reduction device for a working vehicle comprising: The drive wheel is a tire and a wheel on which the tire is mounted,
The transfer speed reducer and the planetary gear mechanism are disposed within the width of the wheel in the rotation axis direction at the inner periphery of the wheel.
The final reduction device for a working vehicle according to claim 1 . The brake mechanism is prior SL has at least one disc-shaped brake disk fixed to the brake shaft, and a fixing portion to which the brake disk is pressed against the brake body portion having, according to claim 1 Final reduction gear for work vehicle. The final reduction device for a working vehicle according to claim 1, wherein the drive source is an electric motor, and an output shaft of the electric motor is arranged coaxially with the input shaft.

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