JP2017144940A - Power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission device comprising a clutch and capable of efficiently transmitting power.SOLUTION: A power transmission device comprises: a drive pinion gear 10; a ring gear 20 which is engaged with the drive pinion gear 10 at a right angle; an input shaft 30 which is arranged coaxially with the drive pinion gear 10; first clutch plates 41 which rotate with the input shaft 30 in an integrated state; second clutch plates 42 which are laminated alternately to the first clutch plates 41; a piston 7 for pressing the first clutch plates 41 and the second clutch plates 42; a clutch housing 3 which rotates with the drive pinion gear 10 and the second clutch plates 42 in an integrated state and receives pressing force of the piston 7; and a front taper roller bearing 14 which is externally fitted to the drive pinion gear 10 at a position closer to a pressing direction side of the piston 7 than the position of the clutch housing 3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power transmission device.

  A final reduction gear (power transmission device) mounted on a vehicle is a device that distributes power generated by a prime mover and decelerated by a transmission to left and right rear drive wheels. The final reduction gear distributes power to the left and right while rotating integrally with the drive gear and the drive pinion gear (first bevel gear) that rotates integrally with the propeller shaft, the ring gear (second bevel gear) that meshes with the drive pinion gear at right angles. A differential device.

In the case of a four-wheel drive vehicle based on a front-wheel drive vehicle, the vehicle should be driven by front-wheel drive under normal driving conditions and the clutch in the final reduction gear should be disconnected to avoid transmitting unnecessary power to the rear wheels. In order to save fuel.
On the other hand, for example, when the road surface is frozen, the ECU (Electronic Control Unit) calculates the power necessary for the rear wheels instantaneously based on signals from various sensors and transmits the power to the rear wheels accordingly. Increases stability.

  In this way, the clutch (power interrupting device) that interrupts (disconnects / connects) the power within the final reduction gear is a multi-plate clutch type device that controls a plurality of clutch plates (friction plates) hydraulically or electromagnetically. Are known.

  In the hydraulic clutch, a plurality of first clutch plates that rotate integrally with an input shaft coupled to a propeller shaft and a plurality of second clutch plates that rotate integrally with a drive pinion shaft that is an output shaft are alternately stacked. It is a device that transmits power by bringing the first clutch plate and the second clutch plate into close contact with each other by a piston that is operated by hydraulic pressure (see Patent Document 1).

JP 2012-219975 A

  Here, in Patent Document 1, when the first clutch plate is pressed against the second clutch plate by hydraulic pressure, this pressing force also acts on the front wall portion of the clutch housing, and the radial ball disposed in front of the clutch housing as it is. Also works on bearings (ball bearings). As a result, an axial load (thrust load) acts on the radial ball bearing, and the friction of the radial ball bearing may increase, leading to a decrease in power transmission efficiency.

  Accordingly, an object of the present invention is to provide a power transmission device that includes a clutch and can efficiently transmit power.

  In order to solve the above-mentioned problems, the present invention provides a first bevel gear, a second bevel gear meshing at right angles with the first bevel gear, a shaft member arranged coaxially with the first bevel gear, and the shaft A first clutch plate that rotates integrally with the member, a second clutch plate that is alternately stacked with the first clutch plate, a pressing member that presses the first clutch plate and the second clutch plate, and the first A pressure receiving member that rotates integrally with the bevel gear and the second clutch plate and receives the pressing force of the pressing member, and a tapered roller that is externally fitted to the first bevel gear on the pressing direction side of the pressing member relative to the pressure receiving member. And a bearing.

  According to such a configuration, even if the clutch is operated to be in a connected state and an axial thrust load acts on the first bevel gear that rotates integrally with the second clutch plate, the thrust load is reduced by the tapered roller bearing. Good support.

Further, the present invention is characterized in that the pressure receiving member is a clutch housing provided with a hole spline that is splined to the second clutch plate.
Further, the present invention is characterized in that the pressure receiving member is a clutch hub provided with a shaft spline that is splined to the second clutch plate.

  By using the pressure receiving member as a clutch housing or a clutch hub that is spline-coupled to the second clutch plate, a simple clutch structure with a reduced number of parts is obtained.

  According to the present invention, it is possible to provide a power transmission device that includes a power interrupt device and can efficiently transmit power.

It is a plane sectional view of the final reduction gear device concerning a 1st embodiment. It is a plane sectional view of the principal part of the final reduction gear device concerning a 1st embodiment. It is a plane sectional view of the principal part of the final reduction gear device according to the second embodiment.

<< First Embodiment >>
A first embodiment of the present invention will be described with reference to FIGS.

≪Configuration of final reduction gear≫
The final reduction gear 1 (power transmission device) according to the present embodiment is mounted on an FF (Front-engine Front-drive) -based four-wheel drive vehicle, and after decelerating the power from a propeller shaft (not shown). A device for transmitting to the left rear wheel and the right rear wheel.

  The final reduction gear 1 includes a drive pinion gear 10 (first bevel gear), a ring gear 20 (second bevel gear), an input shaft 30 (shaft member), a clutch 40 (power interrupting device), and a differential device 200 (difference). Moving device) and a case 100.

<Case>
The case 100 is a shell-like container, and in the front-rear direction, a first case 110 disposed on the front side, a second case 120 disposed on the middle, a third case 130 disposed on the rear side, And these are fastened together by bolts or the like. Then, oil that lubricates the pinion gear 11, the ring gear 20, and the like is collected at the bottom of the case 100.

  The first case 110 is a cylindrical member, and generally accommodates the input shaft 30 and the front half of the clutch 40.

  The second case 120 is a substantially cylindrical member, and has a hemispherical front case portion 121 that is open on the front side, and a rear case portion 122 that is continuous with the rear side of the front case portion 121 and is open on the rear side. And. The front case part 121 generally accommodates the rear half of the clutch 40. The rear case portion 122 generally accommodates the drive pinion gear 10 and the front half of the differential device 200. On the inner peripheral surface of the second case 120, a protrusion 123 for positioning the front taper roller bearing 14 and the rear taper roller bearing 15 described later is formed in an annular shape around the axis O1.

  The third case 130 is a hemispherical shell-shaped member having an opening on the front side, and generally accommodates the rear half of the differential device 200.

<Drive pinion gear>
The drive pinion gear 10 is a rod-like member that rotates about an axis O1 extending in the front-rear direction. The drive pinion gear 10 includes a truncated cone-shaped pinion gear 11 having a small diameter on the rear side, a shaft main body 12 formed on the front side that is the back side of the pinion gear 11, and a front shaft 13 formed on the front side of the shaft main body 12. And.

  The pinion gear 11 meshes with the ring gear 20 at a right angle, and the ring gear 20 constitutes a final reduction gear mechanism. The pinion gear 11 and the ring gear 20 are constituted by hypoid gears, for example.

  Since the pinion gear 11 and the ring gear 20 mesh at right angles, a meshing reaction force (thrust load) acts in the direction of the rotation axis of each gear. In the drive pinion gear 10, a front taper roller bearing (conical roller bearing) 14 and a rear taper roller bearing (conical roller bearing) 15 are used to cope with the thrust load in the direction of the axis O1. The shaft body 12 is supported by the second case 120 via a front taper roller bearing 14 and a rear taper roller bearing 15 at the middle in the axial direction and at the rear end of the shaft, respectively. A collapsible spacer 16 is provided between the front taper roller bearing 14 and the rear taper roller bearing 15. A shim 17 is provided between the rear taper roller bearing 15 and the pinion gear 11.

  The front tapered roller bearing 14 has a structure in which a plurality of rollers 14c roll between the inner ring 14a and the outer ring 14b, and is preloaded in the axial direction so that no gap is generated between the inner ring 14a, the outer ring 14b, and the roller 14c. Has been applied. The front taper roller bearing 14 is provided so that the axis of rotation of each roller 14c approaches the axis O1 as it goes rearward. The inner ring 14 a has a front end in contact with the second hub 4 described later, and a rear end in contact with the collapsible spacer 16. The rear end of the outer ring 14 b is in contact with the protrusion 123 of the second case 120. The front taper roller bearing 14 supports a thrust load in a direction in which the drive pinion gear 10 faces the meshing portion with the ring gear 20, that is, a thrust load toward the rear of the drive pinion gear 10. The front taper roller bearing 14 is externally fitted to the shaft body 12 on the rear side of the attachment portion (spline coupling portion between the second hub 4 and the shaft body 12) of the clutch housing 3 described in detail later.

  The rear tapered roller bearing 15 has a structure in which a plurality of rollers 15c roll between the inner ring 15a and the outer ring 15b, and in the axial direction so that no gap is generated between the inner ring 15a, the outer ring 15b and the roller 15c. Preload is applied. The rear taper roller bearing 15 is provided so as to approach the axis O1 as the rotational axis of each roller 15c moves forward. The inner ring 15 a has a front end in contact with the collapsible spacer 16 and a rear end in contact with the shim 17. The front end of the outer ring 15 b is in contact with the protrusion 123 of the second case 120. The rear taper roller bearing 15 supports a thrust load in a direction in which the drive pinion gear 10 moves away from the meshing portion with the ring gear 20, that is, a thrust load forward of the drive pinion gear 10.

  On the outer peripheral surface of the shaft body 12, a shaft spline 12 a and a male screw 12 b are formed on the front side of the front tapered roller bearing 14 in order toward the front. The shaft spline 12 a is spline-coupled with the hole spline 4 a of the second hub 4 constituting the clutch 40. A lock nut 18 is screwed into the male screw 12 b via a washer 19. By tightening the lock nut 18, the preload of the front taper roller bearing 14 and the rear taper roller bearing 15 is adjusted via the second hub 4.

  The front shaft portion 13 has a smaller diameter than the shaft portion main body 12 on the front side of the shaft portion main body 12. The front shaft portion 13 is disposed in the shaft connection hole 30 a of the input shaft 30 and is supported by the shaft connection hole 30 a via the needle bearing 31.

<Input shaft>
The input shaft 30 is a rod-like member to which power from a propeller shaft (not shown) is input, and is arranged coaxially with the drive pinion gear 10 along the direction of the axis O1. The input shaft 30 has a slightly larger diameter on the rear side. The input shaft 30 is supported by the first case 110 via a radial bearing 32 in the middle in the axial direction.

  A shaft connection hole 30a into which the needle bearing 31 is fitted is formed on the rear end surface of the input shaft 30 around the axis O1. A shaft spline 30b that is spline-coupled with the hole spline 2a of the first hub 2 constituting the clutch 40 is formed on the outer peripheral surface of the rear portion of the input shaft 30. Further, a shaft spline 30c that is spline-coupled with the hole spline 33a of the companion flange 33 is formed on the front outer peripheral surface of the input shaft 30.

<Companion flange>
The companion flange 33 is a member that connects the rear end portion of the propeller shaft (not shown) and the input shaft 30. The companion flange 33 includes a cylindrical portion 34 in which a hole spline 33a is formed on the inner peripheral surface, and a flange portion 35 that extends radially outward from the front end of the cylindrical portion 34. The flange portion 35 is a portion that is bolted to the rear end portion of the propeller shaft. The front end of the input shaft 30 protrudes forward from the front end of the cylindrical portion 34, and the companion flange 33 and the input shaft 30 are integrated by a retaining ring 36 and a washer 37 attached to the outer peripheral surface of the protruding input shaft 30. Is done. The rear end of the cylindrical portion 34 is in contact with the inner ring of the radial bearing 32. An oil seal 38 is provided between the companion flange 33 and the first case 110.

<Ring gear>
The ring gear 20 is a ring-shaped member that rotates about an axis O <b> 2 extending in the left-right direction, and is fastened to the flange portion 213 of the differential case 210 by bolts 21. The lower part of the ring gear 20 is immersed in the lubricating oil staying at the bottom of the case 100, and the lubricating oil is scraped up by the rotation of the ring gear 20.

<Differential device>
The differential device 200 is a device that differentially rotates the left rear wheel and the right rear wheel while transmitting the power from the ring gear 20 to the left rear wheel and the right rear wheel. The differential apparatus 200 includes a substantially cylindrical differential case 210 that rotates about an axis O2, a pinion shaft 221 that is fixed to the differential case 210 and extends in the radial direction, a pair of pinion gears 222 and 222 that rotate about the pinion shaft 221, And a pair of side gears 223 and 223 that mesh with the pinion gears 222 and 222.

  The differential case 210 includes a spherical shell-shaped differential case main body 211, cylindrical boss portions 212 and 212 formed on both sides of the differential case main body 211, and a ring-shaped flange portion extending radially outward from the left end portion of the differential case main body 211. 213.

  Each boss portion 212 is rotatably supported by the second case 120 and the third case 130 via a radial ball bearing 230. A shim 240 for adjusting the meshing backlash between the pinion gear 11 and the ring gear 20 is interposed between the end face of the radial ball bearing 230 and the second case 120 and the third case 130.

  A tip of a drive shaft 250 extending from the left rear wheel or the right rear wheel is splined to each side gear 223. When the vehicle travels on a curve, for example, the left and right side gears 223 and 223 rotate differentially, and the pinion gears 222 and 222 rotate.

<Clutch>
The clutch 40 is a power interrupting device that interrupts (disconnects / connects) the power between the input shaft 30 and the drive pinion gear 10. Here, the clutch 40 is configured as a hydraulic wet multi-plate type.

  The clutch 40 includes a plurality of first clutch plates 41, a plurality of second clutch plates 42, a first hub 2, a clutch housing 3 (pressure receiving member), a second hub 4, and a piston 7 (pressing member). It is equipped with.

  The first clutch plate 41 and the second clutch plate 42 are ring-shaped plate members, and are alternately stacked around the axis O1 in the front-rear direction. A hole spline 41 a is formed on the inner periphery of the first clutch plate 41, and a shaft spline 42 a is formed on the outer periphery of the second clutch plate 42. The first hub 2 has a hole spline 2a formed on the inner peripheral surface and a shaft spline 2b formed on the outer peripheral surface. The hole spline 2 a is spline-coupled with the shaft spline 30 b of the input shaft 30, and the shaft spline 2 b is spline-coupled with the hole spline 41 a of the first clutch plate 41. Thus, the first clutch plate 41 rotates integrally with the input shaft 30 via the first hub 2.

  The clutch housing 3 is formed with a hole spline 3c that is splined with the shaft spline 42a of the second clutch plate 42, and has a cylindrical peripheral wall portion 3a centering on the axis O1 and a radially inward direction from the rear end of the peripheral wall portion 3a. And a ring-shaped rear wall 3b. An opening is formed on the front side of the peripheral wall 3a. A second hub 4 is attached to the inner peripheral edge of the rear wall portion 3b by welding. A hole spline 4 a is formed on the inner peripheral surface of the second hub 4, and this hole spline 4 a is splined to the shaft spline 12 a of the drive pinion gear 10. Thereby, the second clutch plate 42 rotates integrally with the drive pinion gear 10 via the clutch housing 3 and the second hub 4. The clutch housing 3 and the second hub 4 may be configured to be fastened to each other with bolts, rivets or the like, or may be an integrally molded product.

  The rear wall portion 3b is formed with a pressure receiving portion 3d that protrudes forward and contacts the rearmost clutch plate (second clutch plate 42 in the figure) in the clutch plate group. A ring plate-like end plate 5 is disposed in front of the clutch plate group. The piston 7 is a ring-shaped member, is disposed on the front side of the clutch housing 3, and is accommodated in the first case 110 so as to be slidable in the direction of the axis O1. A thrust needle bearing 6 is provided between the end plate 5 and the piston 7. A ring-shaped oil chamber 8 is formed between the front surface of the piston 7 and the first case portion 110. Pressure oil is appropriately supplied to the oil chamber 8 from a hydraulic pump (not shown). When pressure oil is supplied to the oil chamber 8, the piston 7 moves in the direction corresponding to the thrust load that the front taper roller bearing 14 handles, that is, rearward.

≪Operation and effect of final reduction gear≫
According to the final reduction gear 1, the following effects are obtained.

<Clutch-connected state>
The connection state of the clutch 40 will be described. When pressure oil is supplied to the oil chamber 8 from a hydraulic pump (not shown), the piston 7 moves rearward and presses the first clutch plate 41 and the second clutch plate 42 rearward via the end plate 5. As a result, the first clutch plate 41 and the second clutch plate 42 are in close contact with each other in the axial direction to increase the frictional transmission force, and the first clutch plate 41 (input shaft 30) to the second clutch plate 42 (drive pinion gear 10). Power is transmitted to.

  At that time, the clutch housing 3 receives the pressing force in the backward direction by the pressure receiving portion 3d through the laminated body of the first clutch plate 41 and the second clutch plate 42. Accordingly, a thrust load in the rearward direction acts on the drive pinion gear 10 integrated with the clutch housing 3 via the second hub 4. However, the thrust load to the rear is generated by the front taper roller that is externally fitted to the shaft body 12 behind the attachment portion of the clutch housing 3 (spline coupling portion between the second hub 4 and the shaft body 12). Supported by a bearing 14. As a result, even if the pressing force of the piston 7 acts on the clutch housing 3, the bearings supporting the input shaft 30 and the drive pinion gear 10 do not generate any friction due to the thrust load, and the power from the input shaft 30 is It is efficiently transmitted to the drive pinion gear 10 via 40.

<< Second Embodiment >>
A second embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected about the same component as 1st Embodiment, and the description is abbreviate | omitted. In the first embodiment, the clutch housing 3 includes a hole spline 3c that is splined to the second clutch plate 42, whereas the clutch hub 23 of the second embodiment is splined to the second clutch plate 42. A shaft spline 23c is provided.

<Drive pinion gear>
In the first embodiment, the shaft spline 12a and the male screw 12b are formed in the order toward the front on the front side of the front tapered roller bearing 14 on the outer peripheral surface of the shaft main body 12, but in the second embodiment, conversely On the front side of the front tapered roller bearing 14, a male screw 12b and a shaft spline 12a are formed in order toward the front. A lock nut 18 is screwed into the male screw 12 b via a washer 19. The washer 19 is in contact with the inner ring 14 a of the front tapered roller bearing 14. By tightening the lock nut 18, the preload of the front taper roller bearing 14 and the rear taper roller bearing 15 is adjusted.

<Input shaft>
The input shaft 30 includes a round bar-shaped shaft main body 301 and a ring-shaped flange portion 302 extending radially outward from the rear end of the shaft main body 301. The outer peripheral edge of the flange portion 302 is welded to the front wall portion 24b of the clutch case 24 constituting the clutch 40, and the flange portion 302 and the clutch case 24 rotate together. The flange portion 302 and the clutch case 24 may be configured to be fastened with bolts, rivets, or the like, or may be an integrally molded product. The rear portion of the shaft main body 301 is supported by the first case 110 via the radial bearing 32.

<Clutch>
The clutch 40 includes a plurality of first clutch plates 41, a plurality of second clutch plates 42, a clutch case 24, a clutch hub 23 (pressure receiving member), and a piston 7 (pressing member).

  A shaft spline 41 b is formed on the outer peripheral edge of the first clutch plate 41, and a hole spline 42 b is formed on the inner peripheral edge of the second clutch plate 42. The clutch case 24 has a bottomed cylindrical shape with the axis O1 as the center, and includes a peripheral wall portion 24a and a ring-shaped front wall portion 24b extending radially inward from the front end of the peripheral wall portion 24a. . The front wall portion 24b is welded to the flange portion 302 of the input shaft 30 as described above. A shaft spline 41b of the first clutch plate 41 is spline-coupled to a hole spline 24c formed on the inner peripheral surface of the peripheral wall portion 24a. Thereby, the first clutch plate 41 rotates integrally with the input shaft 30 via the clutch case 24.

  The clutch hub 23 is formed with a shaft spline 23c that is spline-coupled with the hole spline 42b of the second clutch plate 42. A ring-shaped hub portion 23b that protrudes and a ring-shaped rear wall portion 23d that extends radially outward from the rear end of the peripheral wall portion 3a are provided. A hole spline 23e is formed on the inner peripheral surface of the hub portion 23b, and the hole spline 23e is splined to the shaft spline 12a of the drive pinion gear 10. The rear end of the hub portion 23b is in contact with a snap ring 25 that is externally fitted to the outer peripheral surface of the shaft body 12. Thus, the second clutch plate 42 rotates integrally with the drive pinion gear 10 via the clutch hub 23. In the clutch hub 23, the peripheral wall portion 23a and the hub portion 23b may be formed of different members and integrated by welding or the like.

  The rear wall portion 23d is a pressure receiving portion that comes into contact with the rearmost clutch plate (first clutch plate 41 in the figure) in the clutch plate group and receives the pressing force of the piston 7. A ring plate-like end plate 5 is disposed in front of the clutch plate group. The piston 7 is a ring-shaped member, is disposed on the front side of the front wall portion 24b of the clutch case 24, and is accommodated in the first case 110 so as to be slidable in the direction of the axis O1. A ring-shaped oil chamber 8 is formed between the front surface of the piston 7 and the first case portion 110. When pressure oil is supplied to the oil chamber 8, the piston 7 moves in the direction corresponding to the thrust load that the front taper roller bearing 14 handles, that is, rearward.

  In order to apply the pressing force of the piston 7 to the end plate 5 through the front wall portion 24 b, a pressing member 9 is provided behind the piston 7 via a thrust needle bearing 6. The pressing member 9 has a ring plate shape centered on the axis O1, and includes a substrate portion 9a disposed in front of the front wall portion 24b and a plurality of columnar pressing members protruding rearward from the rear surface of the substrate portion 9a. Part 9b. A plurality of pressing portions 9b are formed at equal intervals in the circumferential direction. The pressing portion 9 b is inserted through a plurality of through holes 24 d formed in the circumferential direction in the front wall portion 24 b, and the rear end abuts against the end plate 5. As described above, the pressing force of the piston 7 is transmitted to the end plate 5 via the thrust needle bearing 6 and the pressing member 9.

≪Operation and effect of final reduction gear≫
According to the final reduction gear device 1 of the second embodiment, the following operational effects are obtained.
When pressure oil is supplied to the oil chamber 8 from a hydraulic pump (not shown), the piston 7 moves rearward, and the first clutch plate 41 and the second clutch plate 42 are moved rearward via the pressing member 9 and the end plate 5. Press on. As a result, the first clutch plate 41 and the second clutch plate 42 are in close contact with each other in the axial direction to increase the frictional transmission force, and the first clutch plate 41 (input shaft 30) to the second clutch plate 42 (drive pinion gear 10). Power is transmitted to.

  At that time, the clutch hub 23 receives a pressing force in the rear direction by the rear wall portion 23d through the laminated body of the first clutch plate 41 and the second clutch plate 42. Therefore, this pressing force acts as a thrust load on the drive pinion gear 10 through the snap ring 25 that is in contact with the rear end of the hub portion 23b. However, this rear thrust load is generated by the front taper roller bearing that is externally fitted to the shaft main body 12 behind the attachment portion of the clutch hub 23 (spline coupling portion between the hub portion 23b and the shaft main body 12). 14 is supported. As a result, even when the pressing force of the piston 7 acts on the clutch hub 23, no friction caused by the thrust load is generated in the bearings supporting the input shaft 30 and the drive pinion gear 10, and the power from the input shaft 30 is It is efficiently transmitted to the drive pinion gear 10 via 40.

1 Final reduction gear (power transmission device)
3 Clutch housing (pressure receiving member)
7 Piston (Pressing member)
10 Drive pinion gear (first bevel gear)
14 Front taper roller bearing (conical roller bearing)
20 Ring gear (second bevel gear)
23 Clutch hub (pressure receiving member)
30 Input shaft (shaft member)
40 Clutch 41 First clutch plate 42 Second clutch plate

Claims (3)

A first bevel gear;
A second bevel gear meshing at right angles with the first bevel gear;
A shaft member arranged coaxially with the first bevel gear;
A first clutch plate that rotates integrally with the shaft member;
Second clutch plates stacked alternately with the first clutch plates;
A pressing member that presses the first clutch plate and the second clutch plate;
A pressure receiving member that rotates integrally with the first bevel gear and the second clutch plate and receives a pressing force of the pressing member;
A tapered roller bearing externally fitted to the first bevel gear on the pressing direction side of the pressing member relative to the pressure receiving member;
A power transmission device comprising:   2. The power transmission device according to claim 1, wherein the pressure receiving member is a clutch housing including a hole spline that is splined to the second clutch plate.   2. The power transmission device according to claim 1, wherein the pressure receiving member is a clutch hub including a shaft spline that is splined to the second clutch plate. 3.

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