JP7411153B2 - drive device - Google Patents

Description

The present invention relates to a drive device.

Electric drive devices for driving vehicles are known. For example, Japanese Publication No. 2017-534032 describes a configuration in which an output shaft passes through a hollow shaft of a motor.

Japanese Publication: Special Publication No. 2017-534032

In an electric drive as described above, the hollow shaft projects from a first housing section in which the motor is accommodated into a second housing section in which the transmission unit is accommodated; The variable speed transmission mechanism of the transmission mechanism unit is connected within. Here, if the output shaft passes through the hollow shaft, the differential transmission mechanism of the transmission mechanism unit is arranged on the axis of the hollow shaft within the second housing section. Therefore, it may be difficult to perform work such as connecting the speed change transmission mechanism to the hollow shaft within the second housing section, and it may be difficult to assemble the electric drive device.

In view of the above circumstances, one of the objects of the present invention is to provide a drive device that includes a hollow motor shaft through which an axle is passed and has a structure that is easy to assemble.

One aspect of the drive device of the present invention is a drive device that rotates an axle of a vehicle, and includes a motor shaft that is a hollow shaft that rotates around a motor shaft and is open on both sides in the axial direction, and that is fixed to the motor shaft. a motor having a rotor body, a motor drive gear fixed to the motor shaft, a reduction gear connected to the motor shaft, and a reduction gear connected to the reduction gear to rotate the axle around a differential axis. a housing having a motor accommodating portion for accommodating the motor, and a gear accommodating portion for accommodating the speed reduction device and the differential device. The differential shaft coincides with the motor shaft. The axle is passed through the motor shaft. One end of the motor shaft in the axial direction protrudes into the gear accommodating portion. The motor shaft includes a first shaft member to which the rotor body is fixed, and a second shaft member to which the motor drive gear is fixed and connected to one axial side of the first shaft member.

According to one aspect of the present invention, it is possible to easily assemble a drive device including a hollow motor shaft through which an axle is passed.

FIG. 1 is a cross-sectional view showing the drive device of the first embodiment. FIG. 2 is a perspective view showing a part of the motor shaft of the first embodiment. FIG. 3 is a sectional view showing a part of the drive device of the second embodiment. FIG. 4 is a sectional view showing a part of the drive device of the second embodiment.

In the following description, the vertical direction will be defined based on the positional relationship when the drive device of each embodiment shown in each figure is mounted on a vehicle located on a horizontal road surface. In addition, in the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, the Z-axis direction is the vertical direction. The +Z side is the upper side in the vertical direction, and the -Z side is the lower side in the vertical direction. In the following description, the upper side in the vertical direction is simply referred to as the "upper side", and the lower side in the vertical direction is simply referred to as the "lower side". The X-axis direction is a direction perpendicular to the Z-axis direction, and is the front-rear direction of the vehicle in which the drive device is mounted. In each embodiment, the +X side is the front side of the vehicle and the -X side is the rear side of the vehicle. The Y-axis direction is a direction perpendicular to both the X-axis direction and the Z-axis direction, and is the left-right direction (vehicle width direction) of the vehicle. In each embodiment, the +Y side is the left side of the vehicle and the -Y side is the right side of the vehicle. In each embodiment, the right side corresponds to one side in the axial direction, and the left side corresponds to the other side in the axial direction.

Note that the positional relationship in the longitudinal direction is not limited to the positional relationship in each embodiment below, and the +X side may be the rear side of the vehicle and the -X side may be the front side of the vehicle. In this case, the +Y side is the right side of the vehicle and the -Y side is the left side of the vehicle.

A motor shaft J1 appropriately shown in each figure extends in the Y-axis direction, that is, in the left-right direction of the vehicle. In the following description, unless otherwise specified, the direction parallel to the motor shaft J1 is simply referred to as the "axial direction", the radial direction centered on the motor shaft J1 is simply referred to as the "radial direction", and the direction parallel to the motor shaft J1 is simply referred to as the "radial direction". The circumferential direction around the center, that is, the circumferential direction around the motor shaft J1 is simply referred to as the "circumferential direction." Note that in this specification, "parallel directions" include substantially parallel directions, and "orthogonal directions" include substantially orthogonal directions.

<First embodiment>
The drive device 10 of this embodiment shown in FIG. 1 is mounted on a vehicle and rotates the axle AX of the vehicle. The vehicle in which the drive device 10 is mounted is a vehicle that uses a motor as a power source, such as a hybrid vehicle (HEV), a plug-in hybrid vehicle (PHV), or an electric vehicle (EV). As shown in FIG. 1, the drive device 10 includes a housing 11, a motor 20 having a motor shaft 22 that rotates around a motor shaft J1, and a reduction gear device 30 having a motor drive gear 31 fixed to the motor shaft 22. , a differential gear 50, a clutch mechanism 70, a pair of first bearings 27a, 27b, and a pair of second bearings 27c, 27d.

Housing 11 accommodates motor 20, reduction gear 30, and differential gear 50. The housing 11 includes a motor accommodating portion 12 that accommodates the motor 20 and a gear accommodating portion 13 that accommodates the reduction gear device 30 and the differential device 50. Oil O is accommodated inside the housing 11. More specifically, oil O is accommodated inside the motor housing section 12 and the gear housing section 13, respectively. A first oil reservoir OR1 in which oil O is collected is provided in a lower region inside the motor housing portion 12. A second oil reservoir OR2 in which oil O is collected is provided in a lower region inside the gear housing portion 13. The oil level of the first oil reservoir OR1 in the motor housing portion 12 is located above the oil level of the second oil reservoir OR2 in the gear housing portion 13, for example. For example, the oil level of the first oil reservoir OR1 is located below the rotor 21, which will be described later, when the motor 20 is driven. Thereby, it is possible to suppress the rotation of the rotor 21 from being inhibited by the oil O in the first oil reservoir OR1.

The motor accommodating portion 12 has a cylindrical shape that extends in the axial direction centering on the motor shaft J1. The left wall portion 16, which is the left wall portion of the wall portions constituting the motor accommodating portion 12, has a hole 16a that passes through the left wall portion 16 in the axial direction. The axle AX is passed through the hole 16a. A holding portion 16b is provided on the right side of the left side wall portion 16. The right side of the left side wall portion 16 faces the inside of the motor accommodating portion 12 . The holding portion 16b is a recessed portion recessed to the left. The holding portion 16b is a part of the hole 16a. More specifically, the holding portion 16b is the right side portion of the hole 16a. The inner diameter of the holding portion 16b is larger than the inner diameter of the portion of the hole 16a located on the left side of the holding portion 16b. A bearing 81 that rotatably supports the axle AX is fitted into and held in the holding portion 16b from the right side.

The gear accommodating part 13 is located on the right side of the motor accommodating part 12. The lower end of the gear accommodating portion 13 is located below the lower end of the motor accommodating portion 12 . The lower bottom surface of the inner surface of the gear accommodating portion 13 is located lower than the lower bottom surface of the inner surface of the motor accommodating portion 12 . The right wall portion 18, which is the right wall portion of the wall portions constituting the gear accommodating portion 13, has a hole 18a that passes through the right wall portion 18 in the axial direction. The axle AX is passed through the hole 18a.

A holding portion 18b and a holding portion 18c are provided on the left side surface of the right side wall portion 18. The left side surface of the right side wall portion 18 faces the inside of the gear accommodating portion 13 . The holding portion 18b and the holding portion 18c are recessed portions recessed to the right side. The holding portion 18b is a part of the hole 18a. More specifically, the holding portion 18b is the left side portion of the hole 18a. The inner diameter of the holding portion 18b is larger than the inner diameter of the portion of the hole 18a located on the right side of the holding portion 18b. A bearing 82 that rotatably supports the axle AX is fitted into and held in the holding portion 18b from the left side.

The holding part 18c is located above and apart from the holding part 18b. A bearing 35b that rotatably supports a countershaft 34 of the speed reducer 30, which will be described later, is fitted into and held in the holding portion 18c from the left side.

The housing 11 further includes a partition wall 14 and bearing holding walls 15 and 17. The partition wall portion 14 partitions the motor accommodating portion 12 and the gear accommodating portion 13. The partition wall portion 14 constitutes a right wall portion of the motor housing portion 12 . The partition wall portion 14 constitutes a left wall portion of the gear accommodating portion 13. The partition wall 14 has a hole 14a that passes through the partition wall 14 in the axial direction. The axle AX and the motor shaft 22 are passed through the hole 14a.

A protruding cylindrical portion 14e that protrudes to the left is provided on the left side surface of the partition wall portion 14. The protruding cylindrical portion 14e has a cylindrical shape centered on the motor shaft J1. The hole 14a passes through the protruding cylindrical portion 14e in the axial direction. The inside of the protruding cylindrical portion 14e constitutes a part of the inside of the hole 14a. The protruding cylindrical portion 14e is located within the motor accommodating portion 12. A holding portion 14f is provided at the left end of the protruding cylinder portion 14e. The holding portion 14f is a recessed portion recessed to the right. The holding portion 14f is a part of the hole 14a. More specifically, the holding portion 14f is the left end of the hole 14a. The inner diameter of the holding portion 14f is larger than the inner diameter of the portion of the hole 14a adjacent to the right side of the holding portion 14f. A first bearing 27b that rotatably supports the motor shaft 22 is fitted into the holding portion 14f from the left side and held therein.

The partition wall section 14 has an oil passage 14b that connects the inside of the motor housing section 12 and the inside of the gear housing section 13. The oil passage 14b passes through the partition wall portion 14 in the axial direction. In this embodiment, the oil passage 14b extends linearly along the axial direction. The oil passage 14b is located below the hole 14a. The oil O in the motor accommodating part 12 can move into the gear accommodating part 13 via the oil passage 14b. That is, the oil O in the first oil reservoir OR1 can be moved to the second oil reservoir OR2 via the oil passage 14b.

A holding portion 14c and a holding portion 14d are provided on the surface of the partition wall portion 14 on the gear accommodating portion 13 side. In this embodiment, the surface of the partition wall portion 14 on the gear accommodating portion 13 side is the right side surface of the partition wall portion 14 . The holding portion 14c and the holding portion 14d are recessed portions recessed to the left. The holding portion 14c is a part of the hole 14a. More specifically, the holding portion 14c is the right end of the hole 14a. The inner diameter of the holding portion 14c is larger than the inner diameter of the portion of the hole 14a adjacent to the left side of the holding portion 14c. A second bearing 27c that rotatably supports the motor shaft 22 is fitted into the holding portion 14c from the right side and held therein.

The holding portion 14d is a recessed portion recessed to the left. The holding part 14d is located above and apart from the holding part 14c. A bearing 35a that rotatably supports a countershaft 34 of the speed reducer 30, which will be described later, is fitted into and held in the holding portion 14d from the right side.

The bearing holding wall portion 15 extends radially inward from the inner circumferential surface of the motor housing portion 12 . The bearing holding wall portion 15 is located on the left side of the stator 24, which will be described later. The inside of the motor accommodating portion 12 is partitioned in the axial direction by the bearing holding wall portion 15 . The bearing holding wall 15 has a hole 15a that passes through the bearing holding wall 15 in the axial direction. The axle AX and the motor shaft 22 are passed through the hole 15a.

The bearing holding wall portion 15 has a through portion 15b at the lower end. The penetrating portion 15b connects portions of the inside of the motor accommodating portion 12 that are partitioned in the axial direction by the bearing holding wall portion 15. Since the penetrating portion 15b is provided, the first oil reservoir OR1 is provided within the motor accommodating portion 12 so as to straddle the portions on both sides of the bearing holding wall portion 15 in the axial direction.

A holding portion 15c is provided on the right side surface of the bearing holding wall portion 15. The right side surface of the bearing holding wall portion 15 faces the inside of the motor accommodating portion 12 partitioned in the axial direction on the side where a stator 24, which will be described later, is accommodated. The holding portion 15c is a recessed portion recessed to the left. The holding portion 15c is a part of the hole 15a. More specifically, the holding portion 15c is the right side portion of the hole 15a. The inner diameter of the holding portion 15c is larger than the inner diameter of the portion of the hole 15a located on the left side of the holding portion 15c. A first bearing 27a that rotatably supports the motor shaft 22 is fitted into the holding portion 15c from the right side and held therein.

The bearing holding wall portion 17 extends upward from the lower bottom surface of the inner surface of the gear accommodating portion 13 . The bearing holding wall portion 17 is located within the gear housing portion 13 between the differential device 50 and the motor drive gear 31 in the axial direction. The bearing holding wall 17 has a hole 17a that passes through the bearing holding wall 17 in the axial direction. The axle AX and the motor shaft 22 are passed through the hole 17a.

The bearing holding wall portion 17 has a through portion 17b at the lower end. The penetrating portion 17b connects portions of the gear accommodating portion 13 located on both sides of the bearing holding wall portion 17 in the axial direction. Since the penetrating portion 17b is provided, the second oil reservoir OR2 is provided within the gear accommodating portion 13 so as to straddle the portions on both sides of the bearing holding wall portion 17 in the axial direction.

A holding portion 17c is provided on the left side surface of the bearing holding wall portion 17. The holding portion 17c is a concave portion recessed to the right. The holding portion 17c is a part of the hole 17a. More specifically, the holding portion 17c is the left side portion of the hole 17a. The inner diameter of the holding portion 17c is larger than the inner diameter of the portion of the hole 17a located on the right side of the holding portion 17c. A second bearing 27d that rotatably supports the motor shaft 22 is fitted into the holding portion 17c from the left side and held therein.

Although the housing 11 is shown as a single member for simplicity in FIG. 1, the housing 11 is constructed by connecting a plurality of separate members. For example, the motor accommodating part 12 and the gear accommodating part 13 may be separate members and may be fixed to each other via the partition wall 14. In this case, the partition wall portion 14 may be a separate member from the motor accommodating portion 12 and the gear accommodating portion 13, may be integrally molded with the motor accommodating portion 12, or may be integrally molded with the gear accommodating portion 13. You can leave it there. Further, the partition wall portion 14 may be formed by connecting a portion integrally formed with the motor housing portion 12 and a portion integrally molded with the gear housing portion 13 in the axial direction.

The motor 20 outputs torque that rotates the axle AX. Torque of motor 20 is transmitted to axle AX via reduction gear 30 and differential gear 50. In this embodiment, the motor 20 also functions as a generator. The motor 20 functions as a generator during regeneration, for example.

Motor 20 has a rotor 21 and a stator 24. The rotor 21 has a motor shaft 22 and a rotor body 23. The rotor body 23 is fixed to the outer peripheral surface of the motor shaft 22. Although not shown, the rotor main body 23 includes a rotor core and a rotor magnet.

The motor shaft 22 extends in the axial direction centering on the motor shaft J1. The motor shaft 22 is a hollow shaft that is open on both sides in the axial direction. As shown in FIG. 2, the motor shaft 22 has a cylindrical shape centered on the motor shaft J1. As shown in FIG. 1, the motor shaft 22 passes through the partition wall 14 in the axial direction through the hole 14a. The right end of the motor shaft 22 projects into the gear housing 13 .

The motor shaft 22 includes a first shaft member 22a and a second shaft member 22b. The first shaft member 22a and the second shaft member 22b are separate members. The first shaft member 22a and the second shaft member 22b are connected to each other to constitute the motor shaft 22. The second shaft member 22b is connected to the right side of the first shaft member 22a.

The first shaft member 22a is located inside the motor housing section 12. A rotor main body 23 is fixed to the first shaft member 22a. The first shaft member 22a is rotatably supported around the motor shaft J1 by a pair of first bearings 27a and 27b. The pair of first bearings 27a, 27b are rolling bearings. The pair of first bearings 27a, 27b are, for example, ball bearings.

The pair of first bearings 27a and 27b rotatably support portions of the first shaft member 22a located on both sides in the axial direction of the portion to which the rotor main body 23 is fixed. The first bearing 27a is held by the holding portion 15c of the bearing holding wall portion 15, and supports a portion of the first shaft member 22a located on the left side of the rotor body 23. The right end of the first bearing 27a is arranged, for example, at the same position in the axial direction as the right side surface of the bearing holding wall portion 15.

The first bearing 27b is held by the holding portion 14f of the protruding cylindrical portion 14e, and supports a portion of the first shaft member 22a located on the right side of the rotor body 23. That is, of the pair of first bearings 27b, the first bearing 27b located on the second shaft member 22b side (right side) is held by the partition wall portion 14. The left end of the first bearing 27b is arranged, for example, at the same position in the axial direction as the left side surface of the protruding cylindrical portion 14e.

The right end of the first shaft member 22a is inserted into the protruding cylindrical portion 14e, that is, into the hole 14a. The left end of the first shaft member 22a passes through the hole 15a and protrudes into a portion of the inside of the motor accommodating portion 12 that is to the left of the bearing holding wall portion 15. The left end of the first shaft member 22a is the left end of the motor shaft 22.

As shown in FIG. 2, the first shaft member 22a includes a first shaft member main body 22h and a plurality of first protrusions 22i. The first shaft member main body 22h has a cylindrical shape that extends in the axial direction centering on the motor shaft J1. The plurality of first protrusions 22i protrude to the right from the right end of the first shaft member main body 22h. That is, the plurality of first protrusions 22i protrude toward the second shaft member 22b. The plurality of first protrusions 22i are arranged at intervals along the circumferential direction. In this embodiment, the plurality of first protrusions 22i are arranged at equal intervals all around the circumferential direction.

As shown in FIG. 1, the second shaft member 22b is located inside the gear housing portion 13. A motor drive gear 31 is fixed to the second shaft member 22b. Thereby, the speed reducer 30 is connected to the motor shaft 22. The second shaft member 22b is rotatably supported around the motor shaft J1 by a pair of second bearings 27c and 27d. The pair of second bearings 27c and 27d are rolling bearings. The pair of second bearings 27c and 27d are, for example, ball bearings.

The pair of second bearings 27c and 27d rotatably support portions of the second shaft member 22b located on both sides in the axial direction of the portion to which the motor drive gear 31 is fixed. The second bearing 27c is held by the holding portion 14c of the partition wall portion 14, and supports a portion of the second shaft member 22b located on the left side of the motor drive gear 31. That is, of the pair of second bearings 27c and 27d, the second bearing 27c located on the first shaft member 22a side (left side) is held by the partition wall portion 14. The right end of the second bearing 27c is arranged, for example, at the same position in the axial direction as the right side surface of the partition wall 14.

The second bearing 27d is held by the holding portion 17c of the bearing holding wall portion 17, and supports a portion of the second shaft member 22b located on the right side of the motor drive gear 31. The left end of the second bearing 27d is arranged, for example, at the same position in the axial direction as the left side surface of the bearing holding wall 17.

The left end of the second shaft member 22b is inserted into the hole 14a. The right end of the second shaft member 22b passes through the bearing holding wall 17 through the hole 17a and protrudes to the right side of the bearing holding wall 17. The right end of the second shaft member 22b is the right end of the motor shaft 22. The axial dimension of the second shaft member 22b is smaller than the axial dimension of the first shaft member 22a. The inner diameter of the second shaft member 22b is the same as the inner diameter of the first shaft member 22a. The outer diameter of the second shaft member 22b is the same as the outer diameter of the first shaft member 22a.

As shown in FIG. 2, the second shaft member 22b includes a second shaft member main body 22j and a plurality of second protrusions 22k. The second shaft member main body 22j has a cylindrical shape that extends in the axial direction centering on the motor shaft J1. The plurality of second protrusions 22k protrude to the left from the left end of the second shaft member main body 22j. That is, the plurality of second protrusions 22k protrude toward the first shaft member 22a. The plurality of second protrusions 22k are arranged at intervals along the circumferential direction. In this embodiment, the plurality of second protrusions 22k are arranged at regular intervals along the circumferential direction.

The plurality of second protrusions 22k are fitted into gaps between circumferentially adjacent first protrusions 22i in a connected state in which the first shaft member 22a and the second shaft member 22b are connected. As a result, the plurality of first protrusions 22i and the plurality of second protrusions 22k engage with each other in the circumferential direction, thereby preventing relative rotation between the first shaft member 22a and the second shaft member 22b. In this way, the first shaft member 22a and the second shaft member 22b are connected.

As shown in FIG. 1, in this embodiment, the motor shaft 22 has shaft through holes 22c, 22d, 22e, 22f, and 22g that connect the inside of the motor shaft 22 and the outer peripheral surface of the motor shaft 22. In this embodiment, a plurality of shaft through holes 22c, 22d, 22e, 22f, and 22g are provided along the circumferential direction. The shaft through holes 22c, 22d, 22e, and 22f are provided in the first shaft member 22a. The shaft through hole 22g is provided in the second shaft member 22b.

The shaft through holes 22e and 22f are provided in a portion of the first shaft member 22a located between the partition wall portion 14 and the bearing holding wall portion 15 in the axial direction. The shaft through hole 22e is provided in a portion of the first shaft member 22a on the left side of the rotor body 23. The shaft through hole 22f is provided in a portion of the first shaft member 22a on the right side of the rotor body 23. The shaft through holes 22e and 22f face a coil 26, which will be described later, in the radial direction with a gap therebetween.

The shaft through hole 22c is provided in a portion of the first shaft member 22a located in the hole portion 15a. The shaft through hole 22c opens inside the hole 15a. The shaft through hole 22d is provided in a portion of the first shaft member 22a located in the hole portion 14a. The shaft through hole 22d opens inside the hole 14a. The shaft through hole 22g is provided in a portion of the second shaft member 22b located in the hole portion 17a. The shaft through hole 22g opens inside the hole 17a.

The stator 24 faces the rotor 21 in the radial direction with a gap therebetween. The stator 24 is located on the outside of the rotor 21 in the radial direction. The stator 24 includes a stator core 25, an insulator (not shown), and a plurality of coils 26. The plurality of coils 26 are attached to the stator core 25 via an insulator (not shown). Stator 24 is fixed inside motor housing 12 . The lower end of the stator 24 is immersed in the first oil reservoir OR1.

The speed reducer 30 reduces the rotational speed of the motor 20 and increases the torque output from the motor 20 in accordance with the speed reduction ratio. The reduction gear 30 transmits the torque output from the motor 20 to the differential gear 50. The speed reduction device 30 includes a motor drive gear 31, a counter gear 32, a drive gear 33, and a counter shaft 34. The motor drive gear 31 is fixed to a second shaft member 22b of the motor shaft 22 located within the gear housing portion 13. In this embodiment, the motor drive gear 31 is fixed to the axially central portion of the second shaft member 22b.

The counter gear 32 rotates around a counter shaft J2 parallel to the motor shaft J1. The counter shaft J2 is located on the radially outer side of the motor shaft J1. In this embodiment, the counter shaft J2 is located above the motor shaft J1.

Counter gear 32 meshes with motor drive gear 31. Counter gear 32 is located above motor drive gear 31. Drive gear 33 is located on the right side of counter gear 32. The drive gear 33 rotates together with the counter gear 32 around the counter shaft J2. The outer diameter of the drive gear 33 is smaller than the outer diameter of the counter gear 32.

The countershaft 34 extends along the axial direction of the motor shaft 22 with the countershaft J2 as the center. The countershaft 34 is located above the motor drive gear 31. A counter gear 32 and a drive gear 33 are fixed to the outer peripheral surface of the counter shaft 34. Thereby, the counter gear 32 and the drive gear 33 are connected via the counter shaft 34. The counter shaft 34 is rotatably supported around the counter shaft J2 by bearings 35a and 35b.

Bearings 35a and 35b are rolling bearings. The bearings 35a, 35b are, for example, ball bearings. The bearings 35a and 35b are held on both axial walls of the gear accommodating portion 13, respectively. The bearing 35a is held by the holding portion 14d of the partition wall portion 14, which is the left wall portion of the gear housing portion 13, and supports the left end portion of the counter shaft 34. The right end of the bearing 35a is arranged, for example, at the same position in the axial direction as the right surface of the partition wall 14. The bearing 35b is held by a holding portion 18c provided on the right side wall portion 18 of the gear housing portion 13, and supports the right end portion of the countershaft 34. The left end of the bearing 35b is arranged, for example, at the same position as the left side surface of the right wall 18 in the axial direction.

Torque output from motor shaft 22 of motor 20 is transmitted to differential gear 50 via motor drive gear 31, counter gear 32, and drive gear 33 in this order. The gear ratio of each gear, the number of gears, etc. can be changed in various ways depending on the required reduction ratio. In this embodiment, the speed reducer 30 is a parallel shaft gear type speed reducer in which the axes of each gear are arranged in parallel.

Differential gear 50 is connected to speed reduction gear 30 . The differential device 50 is a device for transmitting torque output from the motor 20 to the wheels of the vehicle. The differential device 50 transmits torque to the axle AX and rotates the axle AX around the differential shaft. The differential shaft of the differential device 50 coincides with the motor shaft J1. A pair of axles AX are provided with the differential device 50 interposed in the axial direction. The pair of axles AX extend in the axial direction. The axle AX has a cylindrical shape centered on the motor shaft J1. Of the pair of axles AX, the left axle AX is supported by a bearing 81 held by the holding portion 16b of the left side wall portion 16. Of the pair of axles AX, the right axle AX is supported by a bearing 82 held by the holding portion 18b of the right side wall portion 18. Bearings 81 and 82 are rolling bearings. The bearings 81 and 82 are, for example, ball bearings.

The left axle AX of the pair of axles AX is passed through the inside of the motor shaft 22, which is a hollow shaft. Therefore, compared to the case where the motor shaft J1 and the differential shaft are not arranged coaxially, it is easier to downsize the drive device 10 in the radial direction. Therefore, according to this embodiment, the drive device 10 can be downsized. The left axle AX of the pair of axles AX passes through the motor shaft 22 in the axial direction.

In each of the pair of axles AX, the axial end of the axle AX on the opposite side to the side connected to the differential device 50 protrudes from the housing 11 in the axial direction. Although not shown, in each of the pair of axles AX, a wheel is attached to an axial end portion of the axle AX that protrudes from the housing 11, respectively.

Note that in this specification, "the differential shaft of the differential device matches the motor shaft" refers to not only the case where the differential shaft strictly matches the motor shaft, but also the case where the differential shaft substantially matches the motor shaft. Including cases where In this specification, "the differential shaft substantially coincides with the motor shaft" means that the differential shaft is shifted or tilted relative to the motor shaft within a range that allows the axle to pass through the inside of the motor shaft. include.

The differential device 50 includes a ring gear 51, a pair of pinion gears (not shown), a pinion shaft (not shown), and a pair of side gears (not shown). In this embodiment, ring gear 51 is located on the right side of motor shaft 22 and motor drive gear 31. The ring gear 51 rotates around the differential shaft (motor shaft J1). Ring gear 51 meshes with drive gear 33. Thereby, the torque output from the motor 20 is transmitted to the ring gear 51 via the reduction gear device 30. The lower end of the ring gear 51 is immersed in the second oil reservoir OR2 within the gear housing portion 13. That is, the lower end of the ring gear 51 is immersed in the oil O within the housing 11. As a result, the ring gear 51 rotates, and the oil O is scraped up. The oil O that has been scraped up becomes a mist and is dispersed inside the gear housing portion 13. Thereby, oil O can be supplied to each part arranged inside the gear housing part 13. Further, oil O can also be supplied to the gap between the motor shaft 22 and the axle AX from an opening at the right end of the motor shaft 22.

According to this embodiment, the motor shaft 22 includes a first shaft member 22a to which the rotor body 23 is fixed, and a second shaft member 22b to which the motor drive gear 31 is fixed. Therefore, for example, after arranging the first shaft member 22a to which the rotor body 23 is fixed in the motor accommodating part 12, and arranging the second shaft member 22b in the gear accommodating part 13 and connecting it to the reduction gear device 30, , an assembly method can be adopted in which the motor shaft 22 is manufactured by connecting the first shaft member 22a and the second shaft member 22b. This makes it easier to connect the speed reducer 30 to the motor shaft 22 than when the motor shaft 22 is a single member. Therefore, even if the axle AX is passed through the motor shaft 22 and the differential device 50 is arranged on the axis of the motor shaft 22, the drive device 10 can be easily assembled.

Further, according to the present embodiment, a pair of first bearings 27a, 27b rotatably supports the first shaft member 22a, and a pair of second bearings 27c, 27d rotatably supports the second shaft member 22b. , is provided. Therefore, the motor shaft 22 can be supported by four bearings. Thereby, compared to the case where the motor shaft 22 is supported by two bearings, the motor shaft 22 can be stably supported even if each bearing is made smaller.

Here, the allowable rotation speed of each bearing, which is a rolling bearing, becomes smaller as the inner diameter and outer diameter of each bearing become larger. Therefore, by making each bearing smaller, the allowable rotation speed of each bearing can be increased, and the rotation speed of the motor shaft 22 supported by each bearing can be increased. Thereby, the output of the motor 20 can be improved, and even if the motor 20 is downsized, the necessary output can be obtained. Therefore, the motor 20 can be downsized, and the drive device 10 can be downsized.

Further, one first bearing 27b among the pair of first bearings 27a and 27b and one second bearing 27c among the pair of second bearings 27c and 27d are held by the partition wall portion 14. Here, for example, when the motor shaft is a single member, the rotor main body 23 and the motor drive gear 31 are fixed to the parts on both axial sides of the motor shaft passing through the partition wall part 14, and the partition wall part 14 It is difficult to place a bearing to support the motor shaft in the assembly. Therefore, the structure is such that the motor shaft is supported only by two bearings disposed at both ends in the axial direction, and it becomes necessary to increase the size of the bearings.

In contrast, according to the present embodiment, the motor shaft 22 is configured by connecting a first shaft member 22a and a second shaft member 22b. Therefore, as described above, an assembly method can be adopted in which each shaft member is individually arranged and then connected. This makes it easy to hold one of each pair of bearings that support each shaft member on the partition wall portion 14. Therefore, since the motor shaft 22 is divided into the first shaft member 22a and the second shaft member 22b, the motor shaft 22 passing through the partition wall portion 14 can be easily supported by the four bearings. Therefore, each bearing can be downsized and the drive device 10 can be downsized.

Moreover, when the axle AX is passed through the inside of the motor shaft 22 as in this embodiment, the inner diameter and outer diameter of the motor shaft 22 tend to become large. Therefore, each bearing that supports the motor shaft 22 also tends to become large. Therefore, the effect of reducing the size of each bearing as described above is particularly useful in a configuration in which the axle AX is passed through the inside of the motor shaft 22.

The clutch mechanism 70 switches between a connected state in which the first shaft member 22a and the second shaft member 22b are connected, and a non-connected state in which the first shaft member 22a and the second shaft member 22b are disconnected. . Therefore, by disconnecting the first shaft member 22a and the second shaft member 22b using the clutch mechanism 70, the output of the motor 20 is not transmitted to the speed reducer 30 and the differential gear 50. can. This prevents the motor shaft 22 from rotating even if the wheels connected to the drive device 10 rotate, for example, when the vehicle is driven by power other than the drive device 10 while the drive device 10 is stopped. It can be suppressed. Therefore, it is possible to prevent the motor 20 of the stopped drive device 10 from becoming a load of other power.

Note that the other motive power may be a drive device similar to the drive device 10, or may be an engine. When the other motive power is a drive device similar to drive device 10, these drive devices include, for example, a drive device that rotates the front wheels of the vehicle and a drive device that rotates the rear wheels of the vehicle.

1 and 2 show a connected state in which the first shaft member 22a and the second shaft member 22b are connected. In this embodiment, the clutch mechanism 70 includes a first actuator 71 that moves at least one of the first shaft member 22a and the second shaft member 22b in the axial direction to switch between a connected state and a non-connected state. In this embodiment, the first actuator 71 moves the second shaft member 22b in the axial direction, for example. The first actuator 71 moves the second shaft member 22b to the right from the connected state shown in FIGS. 1 and 2 and separates it from the first shaft member 22a in the axial direction. Disengage the 22k. As a result, the drive device 10 enters a disconnected state in which the first shaft member 22a and the second shaft member 22b are disconnected from each other. As described above, according to the present embodiment, the first shaft member 22a and the second shaft member 22b can be disconnected by directly moving the second shaft member 22b in the axial direction, so that the number of parts of the clutch mechanism 70 can be reduced. can be reduced.

The first actuator 71 is, for example, a linear actuator. In FIG. 1, the first actuator 71 is schematically shown. Although not shown, the first actuator 71 is fixed to the gear housing section 13, for example. The first actuator 71 is controlled by an electronic control device (not shown).

The drive device 10 further includes an electric oil pump (not shown). The electric oil pump is an electric pump that sends oil O inside the housing 11. The electric oil pump is fixed to the housing 11. The electric oil pump supplies oil O to the radial gap between the motor shaft 22 and the axle AX. Therefore, even in a configuration in which the axle AX is passed through the hollow motor shaft 22, the amount of oil O supplied into the motor shaft 22 can be increased by driving the electric oil pump. Thereby, the motor 20 can be suitably cooled. The oil O supplied into the motor shaft 22 is ejected from the shaft through holes 22c, 22d, 22e, 22f, and 22g to the outside of the motor shaft 22, and is supplied to the stator 24 and each bearing.

The drive device 10 further includes an inverter (not shown). An inverter (not shown) is electrically connected to the stator 24 of the motor 20. The power supplied to the stator 24 can be adjusted by the inverter. The inverter is housed in, for example, an inverter case that houses the inverter. The inverter case is fixed to the outer surface of the housing 11. The inverter is controlled by an electronic control device (not shown).

<Second embodiment>
In the motor shaft 122 of the drive device 110 of the present embodiment shown in FIGS. 3 and 4, a plurality of first splines are formed on the outer peripheral surface of the end of the first shaft member 122a on the second shaft member 122b side (right side). A section 122m is provided. Although not shown, the plurality of first spline portions 122m protrude outward in the radial direction, extend in the axial direction, and are arranged at equal intervals all around the circumferential direction. A plurality of second spline portions 122n are provided on the outer peripheral surface of the end of the second shaft member 122b on the first shaft member 122a side (left side). Although not shown, the plurality of second spline portions 122n protrude outward in the radial direction, extend in the axial direction, and are arranged at equal intervals all around the circumferential direction. The first shaft member 122a and the second shaft member 122b are arranged facing each other with a gap in the axial direction.

In this embodiment, the clutch mechanism 170 includes a connecting cylinder member 172 and a second actuator 171. The connecting cylinder member 172 has a cylindrical shape that is open on both sides in the axial direction. The connecting cylinder member 172 has a cylindrical shape centered on the motor shaft J1. The connecting cylinder member 172 is located radially outward from the first shaft member 122a and the second shaft member 122b. The connecting cylinder member 172 is arranged within the hole 14a. The connecting cylinder member 172 has a plurality of spline grooves 172a on its inner peripheral surface. Although not shown, the spline grooves 172a are recessed outward in the radial direction, extend in the axial direction, and are arranged at regular intervals along the circumferential direction. The spline groove 172a is open on both sides in the axial direction.

The second actuator 171 moves the connecting cylinder member 172 in the axial direction, so that the first shaft member 122a and the second shaft member 122b are connected to each other, and the first shaft member 122a and the second shaft member 122b are connected to each other. Switch between the uncoupled state and the uncoupled state. FIG. 3 shows the uncoupled state, and FIG. 4 shows the coupled state.

As shown in FIG. 3, in the unconnected state, the connecting cylinder member 172 is located on the right side of the first shaft member 122a and radially outward of the second shaft member 122b, and surrounds the second shaft member 122b. At this time, the second spline portion 122n is engaged with the spline groove 172a. In the uncoupled state, the left end of the second shaft member 122b is inserted into the connecting cylinder member 172, and the right end of the first shaft member 122a is located outside the connecting cylinder member 172.

On the other hand, as shown in FIG. 4, in the connected state, the connecting cylinder member 172 is located on the radially outer side of the right end of the first shaft member 122a and the left end of the second shaft member 122b. It surrounds the first shaft member 122a and the second shaft member 122b. In the connected state, inside the connecting cylinder member 172, there is an end portion of the first shaft member 122a on the second shaft member 122b side (right side) and an end portion of the second shaft member 122b on the first shaft member 122a side (left side). The ends are inserted. At this time, both the first spline part 122m and the second spline part 122n are fitted into the spline groove 172a. Thereby, relative rotation between the first shaft member 122a and the second shaft member 122b is prevented via the connecting cylinder member 172, and the first shaft member 122a and the second shaft member 122b are connected. The second actuator 171 can bring the drive device 110 into the connected state shown in FIG. 4 by moving the connecting cylinder member 172 to the left from the unconnected state shown in FIG. 3 . The second actuator 171 is, for example, a linear actuator.

According to this embodiment, the drive device 110 can be moved between the connected state and the unconnected state via the connecting cylinder member 172 without moving the first shaft member 122a and the second shaft member 122b in the axial direction. Can be switched. Therefore, switching the state of the drive device 110 is easier than when moving at least one of the first shaft member 122a and the second shaft member 122b in the axial direction.

Further, according to the present embodiment, the axial gap between the first shaft member 122a and the second shaft member 122b can be covered from the outside in the radial direction by the connecting cylinder member 172. Therefore, it is possible to suppress the oil O supplied into the motor shaft 122 from leaking to the outside from the gap between the first shaft member 122a and the second shaft member 122b.

The present invention is not limited to the above-described embodiments, and other configurations may be adopted. The first shaft member and the second shaft member may be connected in any manner. For example, the inner diameter of the first shaft member is larger than the outer diameter of the second shaft member, and the end of the second shaft member is inserted into the inside of the first shaft member, so that the first shaft member and the second shaft member are connected to each other. May be connected. Further, the first shaft member and the second shaft member may be irreleasably coupled. The first shaft member and the second shaft member may each be supported by one bearing. In this case, the bearing that supports the motor shaft may not be held in the partition wall.

The clutch mechanism is not particularly limited as long as it can switch between a connected state and a non-connected state between the first shaft member and the second shaft member. For example, in the first embodiment, the first actuator 71 of the clutch mechanism 70 may move the first shaft member 22a to switch the state, or may move both the first shaft member 22a and the second shaft member 22b. You can also switch the state by A clutch mechanism may not be provided. The configurations described in this specification can be combined as appropriate within a mutually consistent range.

DESCRIPTION OF SYMBOLS 10, 110... Drive device, 11... Housing, 12... Motor accommodating part, 13... Gear accommodating part, 14... Partition wall part, 20... Motor, 21... Rotor, 22, 122... Motor shaft, 22a, 122a... First Shaft member, 22b, 122b...Second shaft member, 22i...First protrusion, 22k...Second protrusion, 23...Rotor body, 27a, 27b...First bearing, 27c, 27d...Second bearing, 30...Reduction Device, 31... Motor drive gear, 33... Drive gear, 50... Differential device, 70, 170... Clutch mechanism, 71... First actuator, 122m... First spline section, 122n... Second spline section, 171... Second Actuator, 172... Connection cylinder member, 172a... Spline groove, AX... Axle, J1... Motor shaft

Claims (5)

A drive device that rotates an axle of a vehicle,
a motor having a motor shaft, which is a hollow shaft that rotates around a motor shaft and is open on both sides in the axial direction, and a rotor body fixed to the motor shaft;
a reduction gear device having a motor drive gear fixed to the motor shaft and connected to the motor shaft;
a differential device connected to the reduction gear device and configured to rotate the axle around a differential shaft;
a housing having a motor accommodating portion that accommodates the motor and a gear accommodating portion that accommodates the speed reduction device and the differential device;
Equipped with
the differential shaft is aligned with the motor shaft;
The axle is passed through the motor shaft,
one end of the motor shaft in the axial direction protrudes into the gear accommodating portion;
The motor shaft is
a first shaft member to which the rotor body is fixed;
a second shaft member to which the motor drive gear is fixed and connected to one axial side of the first shaft member;
has
The apparatus further includes a clutch mechanism that switches between a connected state in which the first shaft member and the second shaft member are connected, and a non-connected state in which the first shaft member and the second shaft member are disconnected. ,
Drive device. The first shaft member has a plurality of first protrusions that protrude toward the second shaft member,
The second shaft member has a plurality of second protrusions that protrude toward the first shaft member,
The plurality of first protrusions are arranged at intervals along the circumferential direction,
The plurality of second protrusions are arranged at intervals along the circumferential direction, and are fitted into gaps between the circumferentially adjacent first protrusions in the connected state,
The clutch mechanism includes a first actuator that moves at least one of the first shaft member and the second shaft member in the axial direction to switch between the connected state and the unconnected state. Drive device. A plurality of first spline portions are provided on the outer peripheral surface of the end of the first shaft member on the second shaft member side,
A plurality of second spline portions are provided on the outer circumferential surface of the end of the second shaft member on the first shaft member side,
The clutch mechanism includes:
a cylindrical connecting cylinder member having a plurality of spline grooves on its inner peripheral surface;
a second actuator that moves the connecting cylinder member in the axial direction to switch between the connected state and the unconnected state;
has
In the connected state, an end of the first shaft member on the second shaft member side and an end of the second shaft member on the first shaft member side are inserted into the connection cylinder member. The drive device according to claim 1 , wherein the first spline portion and the second spline portion are both fitted into the spline groove. a pair of first bearings that rotatably support portions of the first shaft member located on both sides in the axial direction of a portion to which the rotor body is fixed;
a pair of second bearings that rotatably support portions of the second shaft member located on both sides in the axial direction of the portion to which the motor drive gear is fixed;
Furthermore,
The housing has a partition wall portion that partitions the motor housing portion and the gear housing portion,
The motor shaft passes through the partition wall portion in the axial direction,
The first bearing and the second bearing are rolling bearings,
A first bearing of the pair of first bearings located on the second shaft member side and a second bearing of the pair of second bearings located on the first shaft member side are held in the partition wall portion. The drive device according to any one of claims 1 to 3 . A drive device that rotates an axle of a vehicle,
a motor having a motor shaft, which is a hollow shaft that rotates around a motor shaft and is open on both sides in the axial direction, and a rotor body fixed to the motor shaft;
a reduction gear device having a motor drive gear fixed to the motor shaft and connected to the motor shaft;
a differential device connected to the reduction gear device and configured to rotate the axle around a differential shaft;
a housing having a motor accommodating portion that accommodates the motor and a gear accommodating portion that accommodates the speed reduction device and the differential device;
Equipped with
the differential shaft is aligned with the motor shaft;
The axle is passed through the motor shaft,
one end of the motor shaft in the axial direction protrudes into the gear accommodating portion;
The motor shaft is
a first shaft member to which the rotor body is fixed;
a second shaft member to which the motor drive gear is fixed and connected to one axial side of the first shaft member;
has
located on both sides in the axial direction of a portion of the first shaft member to which the rotor body is fixed.
a pair of first bearings rotatably supporting each of the parts;
a pair of second bearings that rotatably support portions of the second shaft member located on both sides in the axial direction of the portion to which the motor drive gear is fixed;
Furthermore,
The housing has a partition wall portion that partitions the motor accommodating portion and the gear accommodating portion,
The motor shaft passes through the partition wall portion in the axial direction,
The first bearing and the second bearing are rolling bearings,
A first bearing of the pair of first bearings located on the second shaft member side and a second bearing of the pair of second bearings located on the first shaft member side are held in the partition wall portion. be done,
Drive device.

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