WO2020250694A1 - Power transmission device and method for manufacturing power transmission device - Google Patents

Abstract

[Problem] To efficiently supply lubricating oil. [Solution] A power transmission device 1 has a motor 2, a reduction mechanism 3 (first planetary reduction gear 4, second planetary reduction gear 5) and differential 6 connected to the downstream side of the motor 2, and a drive shaft 8B passing through the inner periphery of the motor 2. The power transmission device 1 has, an oil delivery mechanism that delivers lubricating oil OL from the motor 2 side toward the reduction mechanism 3 and differential 6 side between the outer periphery of the drive shaft 8B and the inner periphery of the motor 2.

Description

Power transmission device and manufacturing method of power transmission device

The present invention relates to a power transmission device.

Patent Document 1 discloses a power transmission device in which a drive shaft is penetrated on the inner peripheral side of a motor.

Japanese Unexamined Patent Publication No. 2016-89860

The power transmission device of Patent Document 1 discloses a power transmission device in which a drive shaft is penetrated on the inner peripheral side of a gear and a motor.

It is necessary to lubricate the gears that make up the power transmission device with lubricating oil, but it is efficient to use centrifugal force to distribute the lubricating oil throughout the gears. Therefore, it is preferable to supply the lubricating oil to the central shaft side of the gear and distribute the lubricating oil by utilizing the scraping by the rotation of the gear.

Here, in the case of a power transmission device in which a shaft is passed through the inner peripheral side of the motor as in Patent Document 1, it is conceivable that the shaft is a hollow shaft and lubricating oil is supplied from the inside of the hollow shaft. However, the durability of the shaft may be affected. Further, even when the shaft is a hollow shaft while ensuring durability, it may be desired to further increase the supply amount of lubricating oil.

As described above, in the power transmission device in which the drive shaft is penetrated through the inner peripheral side of the gear and the motor, it is required to efficiently supply the lubricating oil from the central shaft side of the gear.

The power transmission device of an aspect of the present invention is
With the motor
With the gear connected to the downstream of the motor,
It has a shaft that penetrates the inner circumference of the motor.
It has an oil feeding structure that feeds lubricating oil from the motor side to the gear side between the outer circumference of the shaft and the inner circumference of the motor.

According to an aspect of the present invention, by having an oil feeding structure for feeding lubricating oil from the motor side to the gear side between the outer circumference of the shaft and the inner circumference of the motor, from the central shaft side of the gear. Lubricating oil can be supplied efficiently. In particular, by forming a spiral groove on the outer circumference of the shaft penetrating the inner circumference of the gear, lubricating oil can be efficiently supplied from the central shaft side of the gear. Further, by forming a spiral groove on the outer circumference of the shaft penetrating the inner circumference of the gear, the lubricating oil can be supplied more efficiently from the central shaft side of the gear. Furthermore, by making the opening areas of the plurality of oil holes provided along the oil feeding direction different, appropriate lubrication is performed according to the required flow rate in consideration of the tendency of the oil pressure to decrease according to the position in the oil feeding direction. Is possible.

It is a figure explaining the power transmission device which concerns on this embodiment. It is an enlarged view around the motor of a power transmission device. It is an enlarged view around the reduction mechanism and the differential device of a power transmission device. It is a figure which shows the catch tank seen from the rotation axis direction at the position A of FIG. It is a figure which shows the oil passage seen from the rotation axis direction at the position B of FIG. It is a figure which shows the flow of the lubricating oil supplied to a spiral groove. It is a figure which shows the spiral groove which concerns on the modification 1. It is a figure explaining the opening area of the oil hole part which concerns on the modification 2. It is a figure explaining the power transmission device which concerns on a further modification.

Hereinafter, embodiments will be described.
FIG. 1 is a diagram illustrating a power transmission device 1 according to the present embodiment.
FIG. 2 is an enlarged view of the power transmission device 1 around the motor.
FIG. 3 is an enlarged view around the reduction mechanism 3 and the differential device 6 as gears of the power transmission device 1.

As shown in FIG. 1, the power transmission device 1 is a reduction mechanism 3 (first planet reduction gear 4, second planet reduction gear 5) that decelerates the output rotation of the motor 2 and the motor 2 and inputs the output rotation to the differential device 6. ) And drive shafts 8A and 8B.

In the power transmission device 1, the reduction mechanism 3 (first planet reduction gear 4, second planet reduction gear 5), the differential device 6, the drive shaft 8A, and the shaft are along the transmission path of the output rotation of the motor 2. The drive shaft 8B and the like are provided.

The output rotation of the motor 2 is decelerated by the speed reduction mechanism 3 and input to the differential device 6, and then the left and right drive wheels of the vehicle on which the power transmission device 1 is mounted (shown) via the drive shafts 8A and 8B. Is transmitted to. In FIG. 1, the drive shaft 8A is rotatably connected to the left wheel of the vehicle equipped with the power transmission device 1, and the drive shaft 8B is rotatably connected to the right wheel.

Here, the first planetary reduction gear 4 is connected to the downstream of the motor 2, and the second planetary reduction gear 5 is connected to the downstream of the first planetary reduction gear 4. The differential device 6 is connected downstream of the second planetary reduction gear 5, and the drive shafts 8A and 8B are connected downstream of the differential device 6.

The motor 2 is housed in the motor case 10. The motor case 10 includes a motor housing 11 that surrounds the outer periphery of the motor 2, motor support portions 12 and 13 that support the motor 2 at both ends in the rotation axis X direction, and motor support portions 12 on the side opposite to the motor housing 11 side. It is composed of an attached cover 14.
The reduction mechanism 3 and the differential device 6 are housed in the gear case 15.

The drive shaft 8A penetrates the opening 150 of the gear case 15 and is inserted into the gear case 15 and connected to the differential device 6. The drive shaft 8A is inserted into the support portion 602 of the differential case 60 constituting the differential device 6 from the rotation axis X direction, and penetrates the inner circumference of the side gear 63A. The drive shaft 8A is rotatably supported by the support portion 602.

A lip seal RS is fixed to the inner circumference of the opening 150, and the lip portion (not shown) of the lip seal RS elastically contacts the outer circumference of the drive shaft 8A to open the outer circumference of the drive shaft 8A. The gap between the inner circumference and the inner circumference of the portion 150 is sealed.

The drive shaft 8B is inserted into the motor case 10 and the gear case 15 and connected to the differential device 6 from the opposite side of the drive shaft 8A in the rotation axis X direction. The drive shaft 8B penetrates through the opening 140 of the cover 14 constituting the motor case 10. A lip seal RS is fixed to the inner circumference of the opening 140, and the lip portion (not shown) of the lip seal RS elastically contacts the outer circumference of the drive shaft 8B to open the outer circumference of the drive shaft 8B. The gap between the inner circumference and the inner circumference of the portion 140 is sealed.

As shown in FIG. 1, the drive shaft 8B is rotatably supported by a bearing B2 as a shaft bearing fixed to a cylindrical support portion 141 of the cover 14.

The drive shaft 8B is externally inserted into the motor shaft 20 as an output shaft of the motor constituting the motor 2 in the motor case 10. The drive shaft 8B penetrates through the through hole 410 of the sun gear 41 constituting the first planetary reduction gear 4 and the through hole 510 of the sun gear 51 constituting the second planet reduction gear 5 in the gear case 15. The drive shaft 8B is inserted into the support portion 601 of the differential case 60 from the rotation axis X direction and penetrates the inner circumference of the side gear 63B. The drive shaft 8B is rotatably supported by the support portion 601 on the same rotation shaft X as the drive shaft 8A.

The motor 2, the reduction mechanism 3 (first planet reduction gear 4, the second planet reduction gear 5) and the differential device 6 are arranged on the rotation axis X of the drive shaft 8B and overlap each other when viewed from the rotation axis X direction. It is provided. Further, the members constituting the motor 2, the reduction mechanism 3 (first planet reduction gear 4, the second planet reduction gear 5), and the differential device 6 are arranged so as to overlap in the radial direction of the rotation axis X. There is.

The motor 2 has a cylindrical motor shaft 20, a cylindrical rotor core 21 extrapolated to the motor shaft 20, and a stator core 25 that surrounds the outer circumference of the rotor core 21 at predetermined intervals.

The motor shaft 20 is extrapolated to the drive shaft 8B. A clearance Cr is provided between the motor shaft 20 and the drive shaft 8B, and the motor shaft 20 is rotatable relative to the drive shaft 8B.
A bearing B1 as a motor bearing is extrapolated and fixed to the motor shaft 20 in the vicinity of one end 20a in the rotation axis X direction. The motor shaft 20 is rotatably supported by a cylindrical wall 132 (see FIG. 2) of the cylindrical motor support portion 13 via a bearing B1.
The motor shaft 20 has a bearing B1 extrapolated and fixed at the other end 20b in the rotation axis X direction, and can rotate on the cylindrical wall 122 (see FIG. 2) of the cylindrical motor support portion 12 via the bearing B1. Is supported by.

The outer circumference of the rotor core 21 is surrounded by the motor housing 11 at predetermined intervals. In the present embodiment, the motor support portion 13 is joined to one end 11a of the motor housing 11, and the motor support portion 12 is joined to the other end 11b of the motor housing 11.

Seal rings S and S are provided on one end 11a and the other end 11b of the motor housing 11. One end 11a of the motor housing 11 is joined to the joining portion 131 formed near the outer edge of the one end surface 13a of the motor support portion 13 without a gap by the seal ring S provided at the one end 11a.

The other end 11b of the motor housing 11 is joined to the joint portion 121 formed near the outer edge of the side wall portion 12a of the motor support portion 12 without a gap by the seal ring S provided on the other end 11b.

As shown in FIG. 2, the inner diameter side of the joint portion 131 of the motor support portion 13 is formed so as to avoid contact with the coil end 253a and the side plate portion 452, which will be described later.
One end surface 13a of the motor support portion 13 is arranged on the inner diameter side of the coil end 253a so as to face one end portion 21a of the rotor core 21 with a gap in the rotation axis X direction.
A cylindrical wall 132 extending in the rotation axis X direction is formed on the inner diameter side of the motor support portion 13, and a bearing B1 for supporting the motor shaft 20 is fixed to the inner circumference of the cylindrical wall 132.

A bearing retainer 135 is fixed to one end surface 13a of the motor support portion 13. The bearing retainer 135 has a ring shape when viewed from the rotation axis X direction. The bearing retainer 135 is in contact with the side surface of the outer race B1b of the bearing B1 from the rotation axis X direction on the inner diameter side of the cylindrical wall 132. The bearing retainer 135 prevents the bearing B1 from falling off from the motor support portion 13.
As shown in FIG. 3, the other end surface 13b of the motor support portion 13 is joined to the open end 151 of the gear case 15 to close the gear case 15.

As shown in FIG. 2, the side wall portion 12a on the motor 2 side of the motor support portion 12 faces the coil end 253b, which will be described later, with a gap on the inner diameter side of the joint portion 121. The wiring W drawn out from the stator core 25 passes between the coil end 253b and the side wall portion 12a. The wiring W is drawn out of the motor case 10 from the lead-out portion 123 formed in the joint portion 121, and is connected to an inverter (not shown). The side wall portion 12b facing the side wall portion 12a of the motor support portion 12 is joined to the end surface 14a of the cover 14.

A cylindrical wall 122 extending in the rotation axis X direction is formed on the inner diameter side of the side wall portion 12a of the motor support portion 12, and a bearing B1 for supporting the other end 20b of the motor shaft 20 is fixed to the inner circumference of the cylindrical wall 122. There is.

The rotor core 21 is formed by laminating a plurality of silicon steel plates, and each of the silicon steel plates is extrapolated to the motor shaft 20 in a state where the relative rotation with the motor shaft 20 is restricted.
When viewed from the rotation axis X direction of the motor shaft 20, the silicon steel plate has a ring shape, and on the outer peripheral side of the silicon steel plate, magnets of N pole and S pole (not shown) alternate in the circumferential direction around the rotation axis X. It is provided in.

One end 21a of the rotor core 21 in the X direction of the rotation axis is positioned by a large diameter portion 203 protruding outward in the radial direction from the outer circumference of the motor shaft 20.

The stator core 25 is formed by laminating a plurality of electromagnetic steel plates, and each of the electromagnetic steel plates has a ring-shaped yoke portion 251 fixed to the inner circumference of the motor housing 11 and a rotor core from the inner circumference of the yoke portion 251. It has a teeth portion 252 that protrudes to the 21 side.

In the present embodiment, a stator core 25 having a configuration in which the winding 253 is distributed and wound across a plurality of tooth portions 252 is adopted, and the stator core 25 is a coil end 253a, 253b protruding in the rotation axis X direction. The length in the rotation axis X direction is longer than that of the rotor core 21 by the amount.

It should be noted that a stator core 25 having a configuration in which the winding 253 is centrally wound may be adopted for each of the plurality of tooth portions 252 protruding toward the rotor core 21 side.

In the inner race B1a of the bearing B1 fixed to the inner circumference of the cylindrical wall 132 of the motor support portion 13, the side surface on the motor 2 side in the rotation axis X direction is in contact with the large diameter portion 203 of the motor shaft 20.

As shown in FIG. 3, the cylindrical wall 132 of the motor support portion 13 faces the side surface 41a of the sun gear 41 of the first planetary reduction gear 4 housed in the gear case 15 with a gap. A lip seal RS is installed between the opening 132a of the cylindrical wall 132 and the motor shaft 20. The lip seal RS is provided to partition the space Sa inside the motor case 10 and the space Sb on the inner diameter side of the gear case 15. The space Sa is a motor chamber that houses the motor 2, and the space Sb is a gear chamber that houses the reduction mechanism 3 and the differential device 6.

Lubricating oil OL (see FIG. 1) of the differential device 6 and the speed reduction mechanism 3 is sealed in the lower part of the space Sb. The lip seal RS is provided to prevent the lubricating oil OL from flowing into the space Sa in the motor case 10.

One end 20a of the motor shaft 20 penetrates the inner circumference of the cylindrical wall 132 of the motor support portion 13 and extends into the space Sb of the gear case 15. One end 20a of the motor shaft 20 is inserted through a through hole 410 of the sun gear 41 constituting the first planetary reduction gear 4. In this state, the sun gear 41 is spline-fitted to the outer periphery of one end 20a of the motor shaft 20 so as not to rotate relative to each other.

Therefore, the output rotation of the motor 2 is input to the sun gear 41 of the first planetary reduction gear 4 via the motor shaft 20, and the sun gear 41 rotates around the rotation axis X by the rotational driving force of the motor 2.

A ring gear 42 fixed to the gear case 15 via an intermediate member 16 is located on the outer diameter side of the sun gear 41 in the radial direction of the rotating shaft X. In the radial direction of the rotating shaft X, between the sun gear 41 and the ring gear 42, the pinion gear 43 rotatably supported by the pinion shaft 44 meshes with the outer circumference of the sun gear 41 and the inner circumference of the ring gear 42. ..

The pinion gear 43 is rotatably supported on the outer circumference of the pinion shaft 44 via the needle bearing NB. The pinion shaft 44 penetrates the pinion gear 43 in the direction of the axis X1 along the rotation axis X. Both ends of the pinion shaft 44 in the axis X1 direction are supported by a pair of side plate portions 451 and 452 of the carrier 45.

The side plate portions 451 and 452 are provided parallel to each other at intervals in the rotation axis X direction.
A plurality of pinion gears 43 (for example, four) are provided between the side plate portions 451 and 452 at predetermined intervals in the circumferential direction around the rotation axis X.

A cylindrical connecting portion 453 is provided on the side plate portion 451 located on the differential device 6 side of the pinion gear 43.
The connecting portion 453 is arranged concentrically with the side plate portion 451 with respect to the rotation axis X, and protrudes along the rotation axis X in a direction approaching the differential device 6 (left direction in the drawing).

The intermediate member 16 that supports the ring gear 42 has a cylindrical shape with both ends open in the X direction of the rotation axis, and extends so as to cover the outer peripheral surface of the ring gear. A disk member 161 projecting outward in the radial direction of the rotating shaft X is joined to the outer circumference. The joint portion 162 formed on the outer diameter side of the disk member 161 is joined to the inner wall of the gear case 15.

A step portion 163 is formed on the inner peripheral surface of the intermediate member 16. The step portion 163 is in contact with the ring gear 42 from the differential device 6 side. The motor 2 side of the ring gear 42 is positioned by a snap ring R engaged with the inner circumference of the intermediate member 16, whereby the movement of the first planet reduction gear 4 in the rotation axis X direction is restricted.
The opening end 164 of the intermediate member 16 on the motor 2 side faces the other end surface 13b of the motor support portion 13 with a gap.

A bearing B3 that supports the tubular portion 552 of the second planetary reduction gear 5, which will be described later, is fixed to the opening 165 on the differential device 6 side of the intermediate member 16.

The connecting portion 453 on the first planetary reduction gear 4 side penetrates the inner peripheral side of the bearing B3 fixed to the opening 165 of the intermediate member 16. The tip 453a of the connecting portion 453 faces the side surface 51a of the sun gear 51 of the second planetary reduction gear 5 at a distance.

A cylindrical connecting portion 511 extending from the sun gear 51 of the second planetary reduction gear 5 is inserted into the inner diameter side of the connecting portion 453 and spline-fitted, and the connecting portion 453 on the first planetary reduction gear 4 side and the connecting portion 453. The connecting portion 511 on the side of the second planetary reduction gear 5 is connected to the inner diameter side of the bearing B3 so as not to rotate relative to each other.

The connecting portion 511 of the sun gear 51 is integrally formed with the sun gear 51, and a through hole 510 is formed so as to straddle the inner diameter side of the sun gear 51 and the inner diameter side of the connecting portion 511. The sun gear 51 is supported so as to be relatively rotatable on the outer circumference of the drive shaft 8B that penetrates the through hole 510.

The side surface 51b of the sun gear 51 on the differential device 6 side faces the tubular support portion 601 of the differential case 60 described later with a gap in the rotation axis X direction, and is between the side surface 51b and the support portion 601. Is intervened by the needle bearing NB.

The sun gear 51 meshes with the large diameter gear portion 531 of the stepped pinion gear 53.

The stepped pinion gear 53 has a large-diameter gear portion 531 that meshes with the sun gear 51, and a small-diameter gear portion 532 that has a smaller diameter than the large-diameter gear portion 531.
The stepped pinion gear 53 is a gear component in which a large-diameter gear portion 531 and a small-diameter gear portion 532 are integrally provided side by side in the direction of the axis X2 parallel to the rotation axis X.

The stepped pinion gear 53 has a through hole 530 penetrating the inner diameter side of the large-diameter gear portion 531 and the small-diameter gear portion 532 in the axis X2 direction.
The stepped pinion gear 53 is rotatably supported on the outer circumference of the pinion shaft 54 penetrating the through hole 530 via the needle bearing NB.

Both ends of the pinion shaft 54 in the axis X2 direction are supported by the side plate portions 651 and the side plate portions 551 constituting the carrier 55.

The side plate portions 651 and 551 are provided in parallel with each other at intervals in the rotation axis X direction.
A plurality (for example, three) of a plurality of stepped pinion gears 53 are provided between the side plate portions 651 and 551 at predetermined intervals in the circumferential direction around the rotation axis X.

Each of the small diameter gear portions 532 meshes with the inner circumference of the ring gear 52. The ring gear 52 is spline-fitted on the inner circumference of the gear case 15, and the ring gear 52 is restricted from rotating relative to the gear case 15.

A tubular portion 552 extending toward the first planetary reduction gear 4 is provided on the inner diameter side of the side plate portion 551. The tubular portion 552 penetrates the opening 165 of the intermediate member 16 from the differential device 6 side to the motor 2 side (right side in the drawing). The tip 552a of the tubular portion 552 faces the side plate portion 451 of the carrier 45 of the first planetary reduction gear 4 at a distance in the rotation axis X direction.

The tubular portion 552 is located on the radial outer side of the meshing portion between the connecting portion 453 on the first planetary reduction gear 4 side and the connecting portion 511 on the second planet reduction gear 5 side. A bearing B3 fixed to the opening 165 of the intermediate member 16 is in contact with the outer periphery of the tubular portion 552. The tubular portion 552 of the side plate portion 551 is rotatably supported by the intermediate member 16 via the bearing B3.

In the second planetary reduction gear 5, one side plate portion 651 of the side plate portion 551 and the side plate portion 651 constituting the carrier 55 is integrally formed with the differential case 60 of the differential device 6.
Therefore, the carrier 55 ( side plate portions 551, 651, pinion shaft 54) of the second planetary reduction gear 5 is formed substantially integrally with the differential case 60.

In the second planetary reduction gear 5, the output rotation of the motor 2 decelerated by the first planetary reduction gear 4 is input to the sun gear 51.
The output rotation input to the sun gear 51 is input to the stepped pinion gear 53 via the large-diameter gear portion 531 that meshes with the sun gear 51, and the stepped pinion gear 53 rotates around the axis X2.

As a result, the small-diameter gear portion 532 integrally formed with the large-diameter gear portion 531 rotates around the axis X2 integrally with the large-diameter gear portion 531.
Here, the small-diameter gear portion 532 meshes with the ring gear 52 fixed to the inner circumference of the gear case 15. Therefore, when the small-diameter gear portion 532 rotates around the axis X2, the stepped pinion gear 53 rotates around the axis X2 while rotating around the axis X2.

Then, since one end 54a of the pinion shaft 54 is supported by the side plate portion 651 formed integrally with the differential case 60, the differential case 60 is interlocked with the circumferential displacement of the stepped pinion gear 53 around the rotation axis X. Rotates around the axis of rotation X.

In the second planetary reduction gear 5, the sun gear 51 is the input unit for the output rotation of the motor 2, and the carrier 55 that supports the stepped pinion gear 53 is the output unit for the input rotation.

The rotation input to the sun gear 51 of the second planetary reduction gear 5 is greatly decelerated by being transmitted from the large-diameter gear portion 531 of the stepped pinion gear 53 to the small-diameter gear portion 532, and then the side plate portion of the carrier 55. The 651 is output to the differential case 60 integrally formed.

As shown in FIG. 1, the differential case 60 is formed in a hollow shape in which the shaft 61, the bevel gears 62A and 62B, and the side gears 63A and 63B are housed therein.
In the differential case 60, tubular support portions 601 and 602 are provided on both sides of the rotation axis X direction (left-right direction in the drawing). The support portions 601 and 602 extend along the rotation axis X in a direction away from the shaft 61.

On the outer diameter side of the support portion 601, a connection piece 56 for connecting the side plate portion 651 and the side plate portion 551 of the carrier 55 is provided.
One end 56a of the connecting piece 56 on the differential case 60 side is provided so as to straddle the side plate portion 651 and the outer circumference of the differential case 60, and the other end 56b is connected to the side plate portion 551 from the rotation axis X direction.

The connection piece 56 is provided at a position avoiding interference with the stepped pinion gear 53 described above. As described above, a plurality (for example, three) of the stepped pinion gears 53 are provided at predetermined intervals in the circumferential direction around the rotation axis X.
The connecting piece 56 is provided between the stepped pinion gears 53 adjacent to each other in the circumferential direction around the rotation axis X.

The inner race B2a of the bearing B2 is fixed to the outer periphery of the support portion 602 of the differential case 60.
The outer race B2b of the bearing B2 is held by the ring-shaped support portion 152 of the gear case 15, and the support portion 602 of the differential case 60 is rotatably supported by the gear case 15 via the bearing B2.

The drive shaft 8A is inserted into the support portion 602, and the drive shaft 8B is inserted into the support portion 601 and each is rotatably supported.

Inside the differential case 60, side gears 63A and 63B are spline-fitted on the outer circumference of the tips of the drive shafts 8A and 8B, and the side gears 63A and 63B and the drive shafts 8A and 8B rotate integrally around the rotation shaft X. It is connected as possible.

The differential case 60 is provided with shaft holes 60a and 60b penetrating in a direction orthogonal to the rotation axis X at positions symmetrical with respect to the rotation axis X.
The shaft holes 60a and 60b are located on the axis Y orthogonal to the rotation axis X, and one end 61a side and the other end 61b side of the shaft 61 are inserted.

One end 61a side and the other end 61b side of the shaft 61 are fixed to the differential case 60 by a pin P, and the shaft 61 is prohibited from rotating around the axis Y.

The shaft 61 is located between the side gears 63A and 63B in the differential case 60, and is arranged along the axis Y.

In the differential case 60, bevel gears 62A and 62B are externally inserted and rotatably supported on the shaft 61.
Two bevel gears 62A and 62B are provided at intervals in the longitudinal direction of the shaft 61 (the axial direction of the axis Y), and the bevel gears 62A and 62B are arranged so that their teeth face each other. ing. In the shaft 61, the bevel gears 62A and 62B are provided so that the axes of the bevel gears 62A and 62B are aligned with the axes of the shaft 61.

In the differential case 60, side gears 63A and 63B are located on both sides of the bevel gears 62A and 62B in the axial direction of the rotating shaft X.
Two side gears 63A and 63B are provided at intervals in the axial direction of the rotating shaft X with their teeth facing each other, and the bevel gears 62A and 62B and the side gears 63A and 63B are mutually provided. It is assembled with the teeth engaged.

In the power transmission device 1, the reduction mechanism 3 (first planet reduction gear 4, second planet reduction gear 5) and the differential device 6 ( bevel gears 62A, 62B, side gear 63A,) are placed on the transmission path of the output rotation of the motor 2. The gears that make up 63B) are arranged.
When the power transmission device 1 is driven, heat is generated in the motor 2, and in the reduction mechanism 3 and the differential device 6, heat is generated at a portion where the gears mesh with each other (gear meshing portion).

Therefore, the lubricating oil OL, which is a medium for cooling, is stored up to a predetermined height inside the gear case 15 that houses the speed reduction mechanism 3 and the differential device 6.
Then, when the differential device 6 rotates around the rotation axis X, the lubricating oil OL in the case is scraped up by the differential case 60, and the scraped up lubricating oil OL is the speed reduction mechanism 3 and the differential device 6. It is supplied to the meshing part of the gear. As a result, the heat generated in the meshing portion of the gear is recovered by heat exchange with the scraped-up lubricating oil OL, and the meshing portion of the gear is cooled.

Here, in order to effectively cool the meshed portion of the gear, it is preferable to supply the lubricating oil OL from the inside of the gear, that is, from the rotation axis X side to the outside in the radial direction by using centrifugal force. However, when the differential case 60 is scraped up, it is difficult to supply the lubricating oil OL to the rotation shaft X side of the gear.

Therefore, in the present embodiment, the power transmission device 1 has a configuration for supplying the lubricating oil OL to the inner diameter side of the gear.
The configuration will be described below.

A spiral groove 81 for feeding the lubricating oil OL is formed on the outer peripheral surface of the drive shaft 8B. The lubricating oil OL is oiled from the motor 2 side toward the differential device 6 side by the spiral groove 81.

The spiral groove 81 draws a spiral extending in the vertical direction around the rotation axis X. The starting end 81a of the spiral groove 81 is located between the other end 20b of the motor shaft 20 and the bearing B2 supported by the support portion 141 of the cover 14 in the rotation axis X direction. The end 81b of the spiral groove 81 is located between the sun gear 51 constituting the second planetary reduction gear 5 and the support portion 601 in the rotation axis X direction. That is, the spiral groove 81 is formed along the rotation axis X across the inside of the motor case 10 and into the gear case 15.

As shown in FIG. 3, inside the gear case 15, oil holes 204 and 512 that supply the lubricating oil OL fed by the spiral groove 81 to the first planetary reduction gear 4 and the second planetary reduction gear 5, respectively. Is formed. The oil hole portion 204 and the oil hole portion 512 are arranged so as to be offset in the rotation axis X direction.

The oil hole portion 204 is formed so as to penetrate the motor shaft 20 externally inserted into the drive shaft 8B in the radial direction. One end of the oil hole 204 opens to the outer peripheral surface of the drive shaft 8B, and the other end opens to the space Sb. The oil hole portion 204 is formed at a position between the sun gear 41 of the first planetary reduction gear 4 and the cylindrical wall 132 of the motor support portion 13 in the X direction of the rotation axis.

The oil hole portion 512 is formed so as to penetrate the connecting portion 511 of the second planetary reduction gear 5 externally inserted into the drive shaft 8B in the radial direction. One end of the oil hole 512 opens to the outer peripheral surface of the drive shaft 8B, and the other end opens to the space Sb. The oil hole portion 512 is formed at a position bordering the sun gear 51 in the X direction of the rotation axis.

Further, as shown in FIG. 1, the power transmission device 1 includes a catch tank 9 (catch portion) for storing a part of the lubricating oil OL scraped up in the gear case 15.
Further, the power transmission device 1 is formed in a pipe 92 for feeding the lubricating oil OL stored in the catch tank 9 to the motor side and a cover 14 as a lubricating oil supply member, and the starting end 81a of the spiral groove 81 from the pipe 92 is formed. Is provided with an oil passage 93 as a lubricating oil supply port for guiding the lubricating oil OL.
The catch tank 9 is installed in the gear case 15 at a position that does not interfere with other components, and is shown by a virtual line in FIG.

FIG. 4A is a diagram showing a catch tank 9 seen from the rotation axis X direction at position A in FIG. 1. FIG. 4B is a diagram showing an oil passage 93 seen from the rotation axis X direction at position B in FIG. 1. 4A and 4B are schematic views, and components not necessary for explanation are omitted.

As shown in FIG. 4A, the catch tank 9 is provided with the upper portion of the gear case 15 bulging in the radial direction.
The catch tank 9 has an opening 9a facing the space Sb in the gear case 15. In FIG. 4A, the portion of the catch tank 9 above the second planetary reduction gear 5 is shown, but the opening 9a extends over the second planetary reduction gear 5 and the first planetary reduction gear 4 (FIG. 4A). 1) is formed.

A discharge port 9b for lubricating oil OL is formed on the bottom surface of the catch tank 9.
Although not shown in FIG. 4A, the discharge port 9b is connected to the pipe 92 shown in FIG. 4B.
The pipe 92 is arranged from the discharge port 9b to the outside of the gear case 15 and the motor case 10 and is connected to the oil passage 93 formed in the cover 14.

As shown in FIG. 1, the oil passage 93 is formed so as to penetrate inward in the radial direction from the outer circumference of the cover 14 to the inner circumference of the support portion 141. The oil passage 93 has a connection portion 93a with the pipe 92 on the outer peripheral side. The oil passage 93 has an opening end 93b on the inner peripheral side of the support portion 141, and the opening end 93b is located above the starting end 81a of the spiral groove 81 formed on the outer peripheral surface of the drive shaft 8B.

The height h1 in the vertical direction of the discharge port 9b of the catch tank 9 is higher than the height h2 in the vertical direction of the connecting portion 93a of the oil passage 93. As a result, the lubricating oil OL discharged from the discharge port 9b flows through the pipe 92 to the motor 2 side according to gravity, and is supplied to the oil passage 93 from the connection portion 93a.

As shown in FIG. 2, a pair of donut-shaped guide plates 94 and 95 are provided inside the support portion 141 to guide the lubricating oil OL to the outer peripheral surface of the drive shaft 8B.

The pair of guide plates 94, 95 face each other with a gap in the rotation axis X direction. The guide plate 94 is attached to the inner circumference of the support portion 141 so as to be sandwiched between the C ring 94a and the bearing B2. The guide plate 95 is attached so as to be sandwiched between the side wall portion 12b of the motor support portion 12 and the end surface 14a of the cover 14. A lip seal RS is installed between the guide plate 95 and the bearing B1 supported by the cylindrical wall 122 of the motor support portion 12, and the lubricating oil OL passing through the oil passage 93 flows into the space Sa in the motor case 10. Prevent that.

The operation of the power transmission device 1 having such a configuration will be described.
As shown in FIG. 1, in the power transmission device 1, the reduction mechanism 3 (first planet reduction gear 4, second planet reduction gear 5) and the differential device 6 are provided along the transmission path of the output rotation of the motor 2. , Drive shafts 8A and 8B are provided.

When the rotor core 21 rotates around the rotation axis X by driving the motor 2, the rotation is input to the sun gear 41 of the first planetary reduction gear 4 via the motor shaft 20 that rotates integrally with the rotor core 21.

As shown in FIG. 3, in the first planetary reduction gear 4, the sun gear 41 is the input unit for the output rotation of the motor 2, and the carrier 45 supporting the pinion gear 43 is the output unit for the input rotation.

When the sun gear 41 rotates around the rotation axis X due to the output rotation of the motor 2, the pinion gear 43 meshing with the outer circumference of the sun gear 41 and the inner circumference of the ring gear 42 rotates around the axis X1 while rotating around the rotation axis X. To do. As a result, the carriers 45 (side plate portions 451 and 452) that support the pinion gear 43 rotate around the rotation axis X at a rotation speed lower than the output rotation of the motor 2.

As described above, the connecting portion 453 of the carrier 45 is connected to the connecting portion 511 of the sun gear 51 on the second planetary reduction gear 5 side, and the rotation of the carrier 45 (the output rotation of the first planetary reduction gear 4) is the first. 2 Input to the sun gear 51 of the planetary reduction gear 5.

In the second planetary reduction gear 5, the sun gear 51 serves as an input unit for the output rotation of the second planetary reduction gear 5, and the carrier 55 supporting the stepped pinion gear 53 serves as an output unit for the input rotation. ing.

When the sun gear 51 rotates around the rotation axis X by the input rotation, the stepped pinion gear 53 (large diameter gear portion 531 and small diameter gear portion 532) rotates around the axis X2 by the rotation input from the sun gear 51 side. To do.
Here, the small-diameter gear portion 532 of the stepped pinion gear 53 meshes with the ring gear 52 fixed to the inner circumference of the gear case 15. Therefore, the stepped pinion gear 53 rotates around the rotation axis X while rotating around the axis X2.

As a result, the carriers 55 (side plate portions 551 and 651) that support the stepped pinion gear 53 rotate around the rotation axis X at a rotation speed lower than the rotation input from the first planetary reduction gear 4 side. The rotation input to the sun gear 51 of the second planetary reduction gear 5 is greatly decelerated by being transmitted from the large-diameter gear portion 531 of the stepped pinion gear 53 to the small-diameter gear portion 532, and then the side plate portion of the carrier 55. The output is output to the differential case 60 (differential device 6) in which the 651 is integrally formed.

Then, when the differential case 60 rotates around the rotation axis X by the input rotation, the drive shafts 8A and 8B rotate around the rotation axis X, and the left and right drive wheels of the vehicle on which the power transmission device 1 is mounted ( (Not shown) is transmitted.

As described above, the lubricating oil OL, which is a cooling medium, is stored in the lower part of the gear case 15.
As shown in FIG. 1, in the embodiment, when one end 61a or the other end 61b of the shaft 61 of the differential case 60 is located at the lowermost side, the one end 61a or the other end 61b of the shaft 61 is at least in the lubricating oil OL. Lubricating oil OL is stored in the gear case 15 up to the position where it is located.

As a result, when the differential case 60 rotates around the rotation axis X, the lubricating oil OL in the gear case 15 is scraped up. The scraped up lubricating oil OL is a gear (side gears 63A and 63B of the differential device 6, bevel gears 62A and 62B, sun gear 41 of the first planetary reduction gear 4, ring gear 42, pinion gear 43, and second planetary reduction gear. The meshing portion is cooled by engaging with the meshing portion of the sun gear 51, the ring gear 52, and the stepped pinion gear 53) of 5.

The lubricating oil OL that has cooled the meshing portion of the gear falls directly or is scattered by the rotation of the gear, travels along the wall surface of the gear case 15, and is stored again in the lower part of the gear case 15, but some of the lubricating oil OL Is stored in the catch tank 9.

As shown in FIG. 4A, the stepped pinion gear 53 rotates around the rotation axis X while rotating around the axis X2 of the pinion shaft 54. The lubricating oil OL supplied to the stepped pinion gear 53 cools the meshing portion of the gear, and at the same time, is scraped up into the gear case 15 again by the rotation of the stepped pinion gear 53. The scraped up lubricating oil OL moves along the rotation direction of the stepped pinion gear 53 due to the centrifugal force generated by the rotation around the rotation axis X of the stepped pinion gear 53, and a part of it moves from the opening 9a to the catch tank 9 Go inside.
Although not shown, in the first planetary reduction gear 4, the lubricating oil OL is similarly scraped up, and a part of the lubricating oil OL is stored in the catch tank 9.

The lubricating oil OL stored inside the catch tank 9 flows from the discharge port 9b to the pipe 92 according to gravity, and falls into the oil passage 93 formed in the cover 14 as shown in FIG. 4B. The lubricating oil OL that has fallen into the oil passage 93 is supplied to the starting end 81a of the spiral groove 81 formed on the outer peripheral surface of the drive shaft 8B through the oil passage 93 and the guide plates 94 and 95 (see FIG. 1).

FIG. 5 is a diagram showing the flow of the lubricating oil OL supplied to the spiral groove 81.
As shown in FIG. 5, centrifugal force acts on the lubricating oil OL supplied to the starting end 81a of the spiral groove 81 by the rotation of the drive shaft 8B, and the spiral groove formed in the circumferential direction of the rotation axis X of the drive shaft 8B. Oil is fed along 81. The lubricating oil OL passes through the inner peripheral side of the motor shaft 20 inside the motor case 10, enters the inside of the gear case 15, and is oil-fed toward the terminal 81b side.

Inside the gear case 15, oil holes 204 and 512 that communicate with the drive shaft 8B are formed. A part of the lubricating oil OL fed through the spiral groove 81 is discharged from the oil holes 204 and 512 and supplied to the inside of the gear case 15.

Since the oil hole portion 204 is formed at a position between the sun gear 41 of the first planetary reduction gear 4 and the cylindrical wall 132 of the motor support portion 13, the lubricating oil OL discharged from the oil hole portion 204 is the first It is supplied from the rotation shaft X side to the meshing portion of the gears (sun gear 41, ring gear 42, stepped pinion gear 43) constituting the planetary reduction gear 4.

Since the oil hole portion 512 is formed at the boundary between the sun gear 51 of the second planetary reduction gear 5 and the connecting portion 511, the lubricating oil OL discharged from the oil hole portion 512 causes the second planetary reduction gear 5 to move. It is supplied from the rotation shaft X side to the meshing portions of the constituent gears (sun gear 51, ring gear 52, stepped pinion gear 53).

Since centrifugal force acts on the lubricating oil OL fed through the spiral groove 81 by the rotation of the drive shaft 8B, the lubricating oil OL is vigorously scattered from the oil holes 204 and 512. As a result, the lubricating oil OL is supplied from the rotation shaft X side to the meshing portions of the gears of the first planet reduction gear 4 and the second planet reduction gear 5, so that the cooling oil is efficiently cooled.

The lubricating oil OL is also supplied to the needle bearing NB that supports the pinion gear 43 from between the motor shaft 20 and the connecting portion 511. It is also supplied to the needle bearing NB that supports each of the sun gear 51 and the support portion 601. These needle bearings NB are also efficiently cooled by supplying the lubricating oil OL from the rotating shaft X side.

The lubricating oil OL remaining in the spiral groove 81 is supplied to the inside of the differential case 60 to which the drive shaft 8B is connected, and the lubricating oil OL is also supplied from the rotating shaft X side to the meshing portion of the gear of the differential case 60. ..

In the embodiment, an oil passage 93 for guiding the lubricating oil OL stored in the catch tank 9 to the drive shaft 8B is formed in the cover 14. This is because it is relatively easy to secure a space on the side opposite to the gear case 15 side of the motor 2.

Specifically, in the embodiment, the bearing B1 that supports the motor 2 and the bearing B2 that supports the drive shaft 8B are provided, respectively, to ensure stable rotation of the motor 2 and the drive shaft 8B. That is, a space is created by increasing the number of bearings, and the oil passage 93 is arranged using this space.

The catch tank 9 of the embodiment also acts to adjust the oil level of the lubricating oil OL in the space Sb of the gear case 15 when the vehicle is running and when the vehicle is stopped.
While the vehicle is running, the lubricating oil OL is scraped up by the rotation of the differential case 60, and the lubricating oil OL is stored in the catch tank 9, so that the oil level of the lubricating oil OL in the space Sb is lowered. When the differential case 60 scoops up the lubricating oil OL, stirring resistance is generated, but by lowering the oil level, the stirring resistance can be reduced. On the other hand, the lubricating oil OL stored in the catch tank 9 is supplied to the spiral groove 81 of the drive shaft 8B via the oil passage 93, and the lubricating oil OL is supplied from the rotating shaft X side to the meshing portion of the gear for cooling. It can be done efficiently.

When the vehicle is stopped, the differential case 60 does not rotate and the lubricating oil OL is not scraped up, so that the oil level of the lubricating oil OL in the space Sb rises. Therefore, when starting the stopped vehicle, the differential case 60 can scrape up a sufficient amount of lubricating oil OL.

As described above, the power transmission device 1 according to the present embodiment has the following configuration.
(1) Motor 2 and
A reduction mechanism 3 and a differential device 6 (gear) connected downstream of the motor 2 and
It has a drive shaft 8B (shaft) that penetrates the inner circumference of the motor 2.
It has an oil feeding structure that feeds lubricating oil OL from the motor 2 side toward the reduction mechanism 3 and the differential device 6 side between the outer circumference of the drive shaft 8B and the inner circumference of the motor 2.
The oil feeding structure is formed including a clearance Cr provided between the drive shaft 8B and the motor shaft 20 (that is, the motor 2) and a spiral groove 81. The spiral groove 81 is not an essential configuration. However, it is preferable to form the spiral groove 81 because the oil feeding efficiency can be further improved.
Further, when the spiral groove 81 is not provided, it is preferable to increase the clearance Cr between the drive shaft 8B and the motor 2 as compared with the case where the spiral groove 81 is provided. If the spiral groove 81 is not provided, gravity acts, so that the lubricating oil OL is fed from the motor 2 side toward the reduction mechanism 3 and the differential device 6 side via the clearance Cr below the drive shaft. become.
In other words, since the hollow shaft of the motor 2 and the drive shaft 8B allow relative rotation, a clearance Cr (gap) between the hollow shaft of the motor 2 and the drive shaft 8B is provided.
The lubricating oil OL that has flowed into the space on the back side of the motor 2 through the pipe 92 flows into the clearance (gap) so as to run through the shaft or overflow from the space on the back side of the motor 2. Then, the oil that has flowed into the clearance Cr (gap) is fed through the oil feeding structure including at least the clearance Cr. That is, it can be said that by pouring the lubricating oil OL into the back side of the motor 2 through the pipe 92 or the like, the lubricating oil OL overflows on the back side of the motor 2 and the oil feeding direction is defined. Further, if the oil feeding structure includes the spiral groove 81, the oil feeding efficiency can be further improved.

An oil feeding structure including a spiral groove 81 and a clearance Cr on the outer periphery of a drive shaft 8B penetrating the inner circumference of the reduction mechanism 3 (first planet reduction gear 4, second planet reduction gear 5) and the differential device 6. By forming the above, the lubricating oil OL can be efficiently supplied from the rotation shaft X side to the meshing portion of the gears of the reduction mechanism 3 and the differential device 6 and bearings such as the needle bearing NB by centrifugal force.

In the power transmission device 1, the vicinity where the reduction mechanism 3 and the differential device 6 of the gear case 15 are arranged has a smaller space than the vicinity where the motor 2 is arranged, and in order to provide the oil passage 93 in this vicinity, It is necessary to secure a space, which may hinder the compactification of the power transmission device 1. Therefore, by setting the shape of the spiral groove 81 so that the lubricating oil OL is fed from the motor 2 side toward the reduction mechanism 3 and the differential device 6, the spiral groove 81 is spiraled into a relatively large space on the motor 2 side. Since the oil passage 93 can be arranged in the groove 81, it is possible to design a compact power transmission device 1.

(2) In the power transmission device 1, the lubricating oil OL is supplied to the spiral groove 81 (that is, the drive shaft 8B) from above.

The power transmission device 1 supplies the lubricating oil OL from the oil passage 93 located above the spiral groove 81 (that is, the drive shaft 8B) in the direction of gravity, and thereby uses the gravity to supply the lubricating oil OL to the spiral groove 81 (that is, the drive shaft 8B). , Drive shaft 8B) can be supplied. As a result, the oil pump becomes unnecessary and the number of parts can be reduced. Further, even when the oil pump is provided, the capacity of the oil pump can be set small by using gravity together.

(3) The power transmission device 1 has a catch tank 9 (catch portion) for storing the lubricating oil OL in the space Sb (gear chamber) provided with the reduction mechanism 3 and the differential device 6, and the catch tank 9 (catch portion). Lubricating oil OL is supplied from the catch portion) to the spiral groove 81 (that is, the drive shaft 8B).

When the catch tank 9 (catch portion) is provided, the catch tank 9 (catch portion) is temporarily lubricated by scraping up the lubricating oil OL by rotating the gears of the reduction mechanism 3 and the differential device 6 while the vehicle is running. Oil OL is stored. That is, it can be said that the catch tank 9 (catch portion) has a function of temporarily storing the lubricating oil OL.
Therefore, when the vehicle is stopped, the oil level of the lubricating oil OL in the space Sb is raised so that the gears can be sufficiently lubricated when the vehicle starts, and the lubricating oil OL is scraped up by the gears while the vehicle is running. By storing the lubricating oil OL in the catch tank 9 (catch portion), the oil level in the space Sb can be lowered, and the stirring resistance of the lubricating oil OL by the gear can be lowered.

By storing a sufficient amount of lubricating oil OL in the catch tank 9 (catch portion) during traveling, the lubricating oil OL is stably supplied to the spiral groove 81 (that is, the drive shaft 8B), and the spiral groove 81 (that is, that is). , The drive shaft 8B) makes it possible to supply the lubricating oil OL to the rotation shaft X side, which is the central shaft of the reduction mechanism 3 and the differential device 6. That is, the lubricating oil OL is supplied to the spiral groove 81 (that is, the drive shaft 8B) via the catch tank 9 (catch portion).
In the embodiment, oil may be supplied from the catch tank 9 (catch portion) to the spiral groove 81 (that is, the drive shaft 8B) by using gravity, or the catch tank 9 (catch) may be supplied by using an oil pump. Oil may be supplied from the portion) to the spiral groove 81 (that is, the drive shaft 8B).

(4) An oil passage 93 (lubricating oil supply port) for supplying lubricating oil OL to the spiral groove 81 (that is, the drive shaft 8B) is provided in the cover 14 (lubricating oil supply member), and the motor 2 has an oil passage 93. Is arranged between the speed reduction mechanism 3 and the differential device 6. That is, the lubricating oil OL is supplied to the spiral groove 81 (that is, the drive shaft 8B) through the oil passage 93 (lubricating oil supply port).

In the motor 2, since it is easy to secure a space on the side opposite to the gear case 15 side, the oil passage 93 can be arranged while minimizing the influence of hindering the compactification of the power transmission device 1.
In the embodiment, the cover 14 constituting the motor case 10 is used as a lubricating oil supply member, and an oil passage 93 is formed in the cover 14 as a lubricating oil supply port, but the present invention is not limited to this. For example, the oil passage 93 may be formed so as to penetrate the inside of the motor support portion 12. Further, the oil passage 93 may be formed as a member separate from the member constituting the motor case 10.

(5) The power transmission device 1 is
Bearing B1 (motor bearing) that supports the motor shaft 20 (motor output shaft) and
It has a bearing B2 (bearing for the shaft) that supports the drive shaft 8B, and has.
Bearing B1 is located between motor 2 and bearing B2.
The oil passage 93 is located between the bearing B1 and the bearing B2.

By providing the bearing B1 that supports the motor shaft 20 and the bearing B2 that supports the drive shaft 8B, the motor 2 and the drive shaft 8B can be rotated stably, and the space created by increasing the number of bearings can be effectively used. By arranging the oil passage 93, the oil passage 93 can be arranged while minimizing the influence of hindering the compactness.

<Modification example 1>
FIG. 6 is a diagram schematically showing a spiral groove 28 according to the first modification.
In the embodiment, as an example of the spiral groove 81 formed on the “outer circumference of the drive shaft 8B”, the spiral groove 81 formed on the “outer peripheral surface of the drive shaft 8B” has been described. However, the "outer circumference of the shaft" is not limited to the "outer peripheral surface of the shaft". The spiral groove may be provided in the outer peripheral direction of the shaft and may be formed on a member facing the outer peripheral surface of the shaft.

For example, as shown in FIG. 6, a spiral groove 28 may be formed on the inner peripheral surface of the motor shaft 20 facing the outer peripheral surface of the drive shaft 8B.

As a result, as in the embodiment, the lubricating oil OL supplied to the outer peripheral surface of the drive shaft 8B is driven by the centrifugal force acting on the rotation of the drive shaft 8B along the spiral groove 28 along the motor case 10 shown in FIG. Oil is fed from the side to the gear case 15 side, and the lubricating oil OL can be efficiently supplied to the meshing portion of the gears of the speed reduction mechanism 3 and the differential device 6.

<Modification 2>
FIG. 7 is a diagram for explaining the opening area of the oil hole portions 204 and 512 according to the modified example 2.
As described in the embodiment, the oil hole portion 204 inside the gear case 15 is supplied with the lubricating oil OL fed by the spiral groove 81 to the first planet reduction gear 4 and the second planet reduction gear 5, respectively. 512 is formed. In the second modification, as shown in FIG. 7, the opening area M1 of the oil hole portion 204 and the opening area M2 of the oil hole portion 512 are different from each other.

In the second modification, the opening area of the oil hole is set so as to increase as the distance from the oil passage 93 in the rotation axis X direction increases. The oil hole portion 512 is located on the downstream side of the oil hole portion 204 in the oil feeding direction of the lubricating oil OL. The distance D2 in the rotation axis X direction from the oil passage 93 to the oil hole portion 512 is farther than the distance D1 in the rotation axis X direction from the oil passage 93 to the oil hole portion 204 (D1 <D2). That is, the opening area M2 of the oil hole portion 512 is set to be larger than the opening area M1 of the oil hole portion 204 (M1 <M2).

The lubricating oil OL that is oil-fed through the spiral groove 81 is subjected to hydraulic pressure due to centrifugal force, but the oil pressure tends to decrease toward the downstream side in the oil-feeding direction. When the oil pressure drops, the lubricating oil OL may not be sufficiently supplied to the meshing portion of the gear.

Therefore, in the second modification, the opening area M2 of the oil hole portion 512 on the downstream side in the oil feeding direction is made larger than the opening area M1 of the oil hole portion 204 on the upstream side in the oil feeding direction.

As an example, the addition amounts A1 and A2 with respect to the reference supply amount of the lubricating oil are determined according to the distances D1 and D2 of the oil hole portions 204 and 512 from the oil passage 93 in the rotation axis X direction, and the respective addition amounts A1. , The opening areas M1 and M2 required to obtain A2 are set. That is, as the distance from the oil passage in the rotation axis X direction increases, the addition amount increases and the set opening area also increases.
The addition amounts A1 and A2 and the opening areas M1 and M2 can be determined by conducting a test or a simulation in advance.

Such a setting is just an example, and the opening area of the oil hole on the downstream side in the oil feeding direction may be simply set to be a certain area larger than the oil hole on the upstream side.

In this way, by setting the opening area M2 of the oil hole portion 512 on the downstream side in the oil feeding direction to be large, the supply amount of the lubricating oil OL in the oil hole portion 512 is increased. As a result, the lubricating oil OL can be appropriately supplied to the meshing portion of the gear even on the downstream side in the oil feeding direction where the oil pressure becomes low.

As described above, the power transmission device 1 according to the modified example 2 has the following configuration.
(6) On the outer circumference of the drive shaft 8B, an oil hole portion 204 (first oil hole portion) formed in the motor shaft 20 (first hollow shaft portion) and a connecting portion 511 (second hollow shaft portion) are formed. An oil hole portion 512 (second oil hole portion) is formed.
The oil hole portion 204 is arranged offset from the oil hole portion 512 in the rotation axis X direction (axial direction).
The opening area M1 of the oil hole portion 204 is different from the opening area M2 of the oil hole portion 512.

Centrifugal from the rotation axis X side by forming a spiral groove 81 on the outer circumference of the drive shaft 8B penetrating the inner circumference of the reduction mechanism 3 (first planet reduction gear 4, second planet reduction gear 5) and the differential device 6. By the force, the lubricating oil OL can be efficiently supplied to the meshing portion of the gears of the reduction mechanism 3 and the differential device 6 and bearings such as the needle bearing NB.

When the lubricating oil OL is fed by the spiral groove 81, the oil pressure tends to decrease toward the downstream side in the oil feeding direction. It is preferable to increase the supply amount of the lubricating oil OL at the position where the oil pressure drops, and it is preferable to set the opening area of the oil hole portion larger as the required supply amount of the lubricating oil OL increases. Based on this tendency, in the modified example 2, the opening areas M1 and M2 of the plurality of oil hole portions 204 and 512 are made different rather than equal. This makes it possible to perform appropriate lubrication according to the required supply amount of the lubricating oil OL.

The oil hole portion can be appropriately provided in the hollow shaft portion located on the outer periphery of the drive shaft 8B, and the installation position and the number of installations are not limited. Further, each oil hole portion may be composed of one oil hole, or may be composed of a plurality of oil holes. When the oil hole portion is composed of a plurality of oil holes, the opening area means the total area of the plurality of oil holes.
In the second modification, the first hollow shaft portion and the second hollow shaft portion are separate shafts of the motor shaft 20 and the connecting portion 511, but the shaft is not limited to this and is integrally formed as the same hollow shaft. You may.

(7) The power transmission device 1 is
The spiral groove 81 has a cover 14 (lubricating oil supply member) provided with an oil passage 93 (lubricating oil supply port) for supplying the lubricating oil OL.
The oil hole portion 512 is farther from the oil passage 93 (that is, the motor 2) in the rotation axis X direction than the oil hole portion 204.
The oil hole portion 512 has a larger opening area than the oil hole portion 204.

Considering that the oil pressure of the spiral groove 81 tends to decrease as it goes downstream in the oil feeding direction, the distance from the oil passage 93 (that is, the motor 2) in the rotation axis X direction is farther toward the downstream side in the oil feeding direction. Increase the opening area of the oil hole. As a result, it is easy to supply the required flow rate of the lubricating oil OL to the downstream side in the oil feeding direction. Further, it is only necessary to adjust the opening areas M1 and M2 of the oil holes 204 and 512, which simplifies the calculation at the time of designing, which leads to a reduction in design man-hours.

<Modification example 3>
In the above-described modification 2, the opening areas M1 and M2 of the oil holes 204 and 512 are set according to the distances D1 and D2 in the rotation axis X direction from the oil passage 93 (that is, the motor 2), but the opening area is set. The elements that set M1 and M2 are not limited to the distance.
As described above, the lubricating oil OL is supplied to the first planetary reduction gear 4 and the second planetary reduction gear 5 via the oil holes 204 and 512, and is generated in the meshing portion of the gear and the bearing such as the needle bearing NB. Cool the heat.

As the rotation speed of bearings such as the needle bearings NB of the first planetary reduction gear 4 and the second planetary reduction gear 5 to which the lubricating oil OL is supplied increases, the heat generation tends to increase. That is, the higher the rotation speed, the larger the required supply amount of the lubricating oil OL tends to be.

In the modified example 3, based on this tendency, in addition to the rotation axis X direction distances D1 and D2 of the oil hole portions 204 and 512, the opening area M1 of the oil hole portions 204 and 512 according to the rotation speed of the supply destination of the lubricating oil OL. , M2 is set.

Specifically, with respect to the reference supply amount of the lubricating oil OL according to the respective rotation speeds of the first planetary reduction gear 4 and the second planetary reduction gear 5 of the holes 204 and 512 to which the lubricating oil OL is supplied. The addition amounts C1 and C2 are determined.

Then, the addition amounts A1 and A2 according to the rotation axis X direction distances D1 and D2 of the oil hole portions 204 and 512 and the addition amounts C1 and C2 according to the rotation speed are set as parameters, respectively, and the oil hole portions 204 and 512 are set. The opening areas M1 and M2 of the above are determined.

Here, since the actual rotation speeds of the first planetary reduction gear 4 and the second planetary reduction gear 5 change according to the traveling state, even if the addition amounts C1 and C2 are determined from the respective reference rotation speeds V1 and V2, respectively. good. The larger the reference rotation speeds V1 and V2, the larger the addition amounts C1 and C2 are set.

The reference rotation speeds V1 and V2 can be calculated from the reduction ratios and the like from the motor 2 to each of the first planetary reduction gear 4 and the second planetary reduction gear 5. For example, the reference rotation speeds V1 and V2 can be determined according to the rotation speeds of the first planetary reduction gear 4 and the second planetary reduction gear 5 when the rotation of the motor 2 is a predetermined rotation.

The addition amounts C1 and C2 and the opening areas M1 and M2 can be determined by conducting a test or simulation in advance in the same manner as in the modified example 2.

As described above, the power transmission device 1 according to the modification 3 is
(8) The spiral groove 81 has a cover 14 (lubricating oil supply member) provided with an oil passage 93 (lubricating oil supply port) for supplying the lubricating oil OL.
The opening area M1 of the oil hole portion 204 and the oil hole portion 512 is increased as the addition amounts A1 and A2 (first addition amount) according to the distance (distance) in the rotation axis X direction from the oil passage 93 (that is, the motor 2) are larger. , M2 is set large.
The oil hole portion 204 and the oil hole portion 512 are addition amounts C1 and C2 (second addition amount) according to the reference rotation speeds V1 and V2 of the first planet reduction gear 4 and the second planet reduction gear 5 (lubricating oil supply destination). ) Is larger, the opening areas M1 and M2 are set larger.
The larger the distances D1 and D2 in the X direction of the rotation axes, the larger the addition amounts A1 and A2 are set.
The larger the reference rotation speeds V1 and V2, the larger the addition amounts C1 and C2 are set.

The manufacturing method of the power transmission device 1 according to the third modification is as follows.
(9) The power transmission device 1 is
Motor 2 and
A reduction mechanism 3 and a differential device 6 (gear) connected downstream of the motor 2 and
A drive shaft 8B (shaft) that penetrates the inner circumference of the motor 2 and
It has an oil feeding structure for feeding lubricating oil from the motor 2 side toward the reduction mechanism 3 and the differential device 6 side between the outer circumference of the drive shaft 8B and the inner circumference of the motor 2.
On the outer circumference of the drive shaft 8B, oil formed in the oil hole portion 204 (first oil hole portion) formed in the motor shaft 20 (first hollow shaft portion) and the oil formed in the connecting portion 511 (second hollow shaft portion). A hole portion 512 (second oil hole portion) is formed.
The oil hole portion 204 is arranged offset from the oil hole portion 512 in the rotation axis X direction (axial direction).
The power transmission device 1 has a cover 14 (lubricating oil supply member) provided with an oil passage 93 (lubricating oil supply port).
Lubricating oil OL is supplied to the drive shaft 8B via the oil passage 93.
The opening area M1 of the oil hole portion 204 and the oil hole portion 512 is increased as the addition amounts A1 and A2 (first addition amount) according to the distance (distance) in the rotation axis X direction from the oil passage 93 (that is, the motor 2) are larger. , M2 is set large.
The oil hole portion 204 and the oil hole portion 512 are addition amounts C1 and C2 (second addition amount) according to the reference rotation speeds V1 and V2 of the first planet reduction gear 4 and the second planet reduction gear 5 (lubricating oil supply destination). ) Is larger, the opening areas M1 and M2 are set larger.
The larger the distances D1 and D2 in the X direction of the rotation axis, the larger the addition amounts A1 and A2 are set.
The larger the reference rotation speeds V1 and V2, the larger the addition amounts C1 and C2 are set.

Considering that the oil pressure of the spiral groove 81 tends to decrease toward the downstream side in the oil feeding direction, the distances D1 and D2 in the X direction of the rotation axis from the oil passage 83 (that is, the motor 2) of the oil holes 204 and 512 The additional amounts A1 and A2 of the corresponding lubricating oil OL are set, and the opening areas M1 and M2 of the oil holes 204 and 512 are set according to the added amounts A1 and A2. Since the addition amounts A1 and A2 become larger toward the downstream side of the spiral groove 81 in the oil feeding direction, the opening areas M1 and M2 are set in the direction of increasing.

Further, the higher the rotation speed of the first planetary reduction gear 4 and the second planetary reduction gear 5, which are the supply destinations of the lubricating oil OL, the more easily heat is generated, and the reference rotation speed is increased in view of the fact that the required supply of the lubricating oil OL increases. The addition amounts C1 and C2 are set according to V1 and V2, and the opening areas M1 and M2 are set according to the addition amounts C1 and C2. Since the addition amounts C1 and C2 increase as the reference rotation speeds V1 and V2 increase, the opening areas M1 and M2 are set in a direction of increase. As a result, the lubricating oil OL can be appropriately supplied according to the required supply amount.

Here, the term "downstream connection" as used herein means a connection relationship in which power is transmitted from a component arranged upstream to a component arranged downstream.
For example, the case of the first planetary reduction gear 4 connected downstream of the motor 2 means that power is transmitted from the motor 2 to the first planetary reduction gear 4.

Further, in the embodiment, the sun gear 41, the ring gear 42 and the pinion gear 43 constituting the first planetary reduction gear 4 of the reduction mechanism 3 and the sun gear 51, the ring gear 52 and the ring gear 52 constituting the second planetary reduction gear 5 are used as gears. Although the stepped pinion gear 53 and the bevel gears 62A and 62B and the side gears 63A and 63B constituting the differential device 6 have been described, the present invention is not limited to this, and the present invention can be applied to other gears.

Further, although the drive shaft 8B has been described as the shaft in the embodiment, the present invention is not limited to this, and the present invention can be applied to other shafts.
Further, in the embodiment, the drive shaft 8B has been described as a solid shaft, but the drive shaft 8B may be a hollow shaft and the lubricating oil OL may be supplied from the inside of the hollow shaft. As a result, the lubricating oil OL can be more efficiently supplied together with the spiral groove 81 formed on the outer periphery of the drive shaft 8B.

As described in the embodiment, in the present invention, the spiral groove 81 (see FIG. 1) is not an indispensable configuration. Therefore, as shown in FIG. 8, the power transmission device 1 has a configuration in which the spiral groove is not provided. It is also possible to do.

Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments shown in these embodiments. It can be changed as appropriate within the scope of the technical idea of the invention.

1 Power transmission device 10 Motor case 11 Motor housing 12 Motor support 13 Motor support 14 Cover (lubricating oil supply member)
15 Gear case 16 Intermediate member 2 Motor 20 Motor shaft (motor output shaft) (1st hollow shaft)
203 Large diameter part 204 Oil hole part (1st oil hole part)
21 Rotor core 25 Stator core 28 Spiral groove 3 Reduction mechanism (gear)
4 1st planetary reduction gear 41 Sun gear 410 Through hole 42 Ring gear 43 Pinion gear 44 Pinion shaft 45 Carrier 5 2nd planet reduction gear 51 Sun gear 512 Oil hole 52 Ring gear 53 Stepped pinion gear 54 Pinion shaft 55 Carrier 56 Connection piece 6 Differential device (gear)
60 Diff case 61 Shaft 62A, 62B Bevel gear 8A Drive shaft 8B Drive shaft (shaft)
81 Spiral groove 81a Start end 81b End end 9 Catch tank (catch part)
92 Piping 93 Oil passage (lubricant supply port)
94, 95 Guide plate B1 bearing (bearing for motor)
B2 bearing (bearing for shaft)
B3 Bearing OL Lubricating oil Sa space (motor room)
Sb space (gear room)

Claims (11)

1. With the motor
   With the gear connected to the downstream of the motor,
   It has a shaft that penetrates the inner circumference of the motor.
   A power transmission device having an oil feeding structure for feeding lubricating oil from the motor side to the gear side between the outer circumference of the shaft and the inner circumference of the motor.
2. In claim 1,
   The oil feeding structure is a power transmission device including a clearance provided between the shaft and the motor.
3. In claim 1 or 2,
   The oil feeding structure is a power transmission device provided on the outer periphery of the shaft and including a spiral groove for oil feeding lubricating oil from the motor side to the gear side.
4. In any one of claims 1 to 3,
   A power transmission device that supplies lubricating oil to the shaft from above.
5. In any one of claims to 4.
   It has a catch portion for storing lubricating oil in the gear chamber provided with the gear.
   A power transmission device in which lubricating oil is supplied to the shaft via the catch portion.
6. In any one of claims 1 to 5,
   Lubricating oil supply port is provided in the lubricating oil supply member,
   Lubricating oil is supplied to the shaft through the lubricating oil supply port.
   The motor is a power transmission device arranged between the lubricating oil supply port and the gear.
7. In claim 6,
   A motor bearing that supports the output shaft of the motor,
   With a shaft bearing that supports the shaft,
   The motor bearing is located between the motor and the shaft bearing.
   The lubricating oil supply port is a power transmission device located between the motor bearing and the shaft bearing.
8. In any one of claims 1 to 7,
   A first oil hole portion formed in the first hollow shaft portion and a second oil hole portion formed in the second hollow shaft portion are formed on the outer periphery of the shaft.
   The first oil hole portion is arranged so as to be offset in the axial direction from the second oil hole portion.
   A power transmission device in which the opening area of the first oil hole is different from the opening area of the second oil hole.
9. In claim 8.
   The second oil hole portion has a longer axial distance from the motor than the first oil hole portion.
   A power transmission device in which the second oil hole portion has a larger opening area than the first oil hole portion.
10. In claim 8.
    The opening area of the first oil hole portion and the second oil hole portion is set to be larger as the first addition amount according to the distance from the motor is larger.
    The opening area of the first oil hole portion and the second oil hole portion is set to be larger as the second addition amount according to the reference rotation speed of the lubricating oil supply destination is larger.
    The larger the distance, the larger the first addition amount is set.
    A power transmission device in which the second addition amount is set larger as the reference rotation speed is larger.
11. With the motor
    With the gear connected to the downstream of the motor,
    It has a shaft that penetrates the inner circumference of the motor.
    It has an oil feeding structure that feeds lubricating oil from the motor side to the gear side between the outer circumference of the shaft and the inner circumference of the motor.
    A first oil hole portion formed in the first hollow shaft portion and a second oil hole portion formed in the second hollow shaft portion are formed on the outer periphery of the shaft.
    The first oil hole portion is a method for manufacturing a power transmission device arranged so as to be offset in the axial direction from the second oil hole portion.
    The power transmission device has a lubricating oil supply member provided with a lubricating oil supply port.
    Lubricating oil is supplied to the shaft through the lubricating oil supply port.
    The opening area of the first oil hole portion and the second oil hole portion is set to be larger as the first addition amount according to the distance from the motor is larger.
    The opening area of the first oil hole portion and the second oil hole portion is set larger as the second addition amount according to the reference rotation speed of the lubricating oil supply destination is larger.
    The larger the distance, the larger the first addition amount is set.
    A method for manufacturing a power transmission device, wherein the larger the reference rotation speed is, the larger the second addition amount is set.

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