Vehicle drive device

Abstract

The present application relates to a vehicle drive device. A vehicle drive device (100) configures a rotary electric machine (1), a planetary gear mechanism (4), and an output differential gear device (5) on the same axis, a differential case (51) is supported by a case (9) in a state of being able to rotate with respect to the case (9) in a radial direction (R) via a bushing (B5) that is disposed on the side opposite to the side where the planetary gear mechanism (4) is located and overlaps the differential gear mechanism (50) in an axial direction (L), and a carrier (CR) is supported by the case (9) in a state of being able to rotate with respect to the case (9) in the radial direction (R) via a rolling bearing (B4).

Description

Technical Field

[0001] This invention relates to a vehicle drive system. Background Technology

[0002] International Publication No. 2023 / 068334 discloses a so-called single-shaft type vehicle drive unit 100, which includes a rotary motor 1 that serves as the driving force source for a pair of wheels W1 and W2, a planetary gear mechanism 4 that functions as a reducer, and a differential gear device 5 that distributes power to the pair of wheels W1 and W2, all arranged coaxially. In the background art, the reference numerals in parentheses are reference numerals to the accompanying drawings. The planetary gear mechanism 4 is a two-stage planetary gear mechanism shared by a planet carrier CR1, and includes: a sun gear SG1, a first planetary gear PG1 meshing with the sun gear SG1, a first ring gear RG1 meshing with the first planetary gear PG1, a second planetary gear PG2 supported by the planet carrier CR1 and rotating integrally with the first planetary gear PG1, and a second ring gear RG2 meshing with the second planetary gear PG2. With the first ring gear RG1 fixed and the planet carrier CR1 in a free state, and the input from the sun gear SG1 of the planetary gear mechanism output from the second ring gear RG2, the radial dimension of this planetary gear mechanism 4 can be kept small, and a high reduction ratio of at least about 20 can be achieved. Because this vehicle drive unit 1 can easily achieve a large reduction ratio, it is easy to amplify torque and to miniaturize the rotary motor 1.

[0003] Furthermore, in the single-shaft type vehicle drive unit 100, when using a reducer based on the planetary gear mechanism 4 as described above, it is easy to implement a design that counteracts the meshing reaction force of the radial gears, and torque loss in the power transmission path can be reduced by omitting the radial bearing. In addition to making it easier to miniaturize the rotary motor 1, the vehicle drive unit 100 can be configured to be smaller since the radial bearing is not provided.

[0004] Patent Document 1: International Publication No. 2023 / 068334

[0005] As mentioned above, if the automotive drive unit is miniaturized by reducing the number of radial bearings, the centrifugal force caused by the eccentricity of the rotor of the rotary motor tends to increase when the rotary motor rotates at high speed. As a result, the planetary gears tend to wobble, and the rotor rotation as a whole of the automotive drive unit exhibits significant primary vibration. To suppress such vibration, the following consideration is made: either (i) the planetary carrier supporting the planetary gears, and (ii) the input rotating member of the differential gear device that rotates integrally with the output rotating member of the planetary gear mechanism, i.e., the second ring gear, are radially supported in the housing via bearings or the like. However, if the number of radial bearings or the like is increased carelessly, the torque loss in the power transmission path will increase. In addition, there is a concern that the radial dimension of the automotive drive unit will increase due to the installation of such a radial support mechanism. Summary of the Invention

[0006] In view of the above background, in a single-shaft type automotive drive unit that includes a two-stage planetary gear mechanism with a sun gear, two planetary gears supported by a common planet carrier, and two ring gears as a reducer, it is desirable to suppress the increase of torque loss in the power transmission path and reduce the primary vibration of the rotor rotation.

[0007] The vehicle drive system according to the above-described situation includes: a rotary motor having a rotor; a first output component connected to a first wheel drive; a second output component connected to a second wheel drive; a planetary gear mechanism that reduces the rotation of the rotor; an output differential gear device having a differential housing and a differential gear mechanism housed in the differential housing, distributing the rotation transmitted from the planetary gear mechanism to the differential housing to the first output component and the second output component; and a housing housing the rotary motor, the planetary gear mechanism, and the output differential gear device, wherein the rotary motor, the first output component, the second output component, the planetary gear mechanism, and the output differential gear device are arranged coaxially, the planetary gear mechanism having a sun gear, a planet carrier, a first ring gear, and a second ring gear, the sun gear being integrally rotated with the rotor, and the first ring gear... The second gear ring is connected to the differential housing in an integral rotatable manner, and the planetary carrier supports the first and second pinions, which rotate integrally with each other, so that they can rotate. The first pinion meshes with the sun gear and the first gear ring. The diameter of the second pinion is smaller than that of the first pinion, and the second pinion meshes with the second gear ring. The direction along the rotation axis of the rotor is defined as the axial direction, and the direction orthogonal to the rotation axis is defined as the radial direction. The differential housing is supported by the housing in the radial direction via a bushing so that it can rotate relative to the housing. The bushing is arranged on the side opposite to the side where the planetary gear mechanism is located and overlaps with the differential gear mechanism when viewed along the axial direction. The planetary carrier is supported by the housing in the radial direction via rolling bearings so that it can rotate relative to the housing.

[0008] According to this structure, the planetary carrier supporting the first and second pinions is radially supported by the housing via rolling bearings. Thus, even if vibration caused by rotor eccentricity is transmitted via the first pinion, planetary carrier vibration can be suppressed. The output differential gear unit is supported on the planetary gear mechanism side by self-centering caused by the meshing of the second ring gear, and on the opposite side of the planetary gear mechanism by bushings with a slight radial clearance relative to the housing. Even without strong radial support, the output differential gear unit is suppressed because the vibration of the planetary carrier is suppressed, thus preventing further transmission of vibration caused by eccentricity to the output differential gear unit via the second pinion. The additional radial support is essentially limited to the rolling bearings supporting the planetary carrier, thus suppressing any increase in torque loss in the power transmission path from the rotating motor to the output component. Thus, according to this structure, in a single-shaft type vehicle drive unit that includes a two-stage planetary gear mechanism with a sun gear, two planetary gears supported by a common planet carrier, and two ring gears as a reducer, it is possible to suppress the increase of torque loss in the power transmission path and reduce the primary vibration of the rotor rotation.

[0009] Further features and advantages of the vehicle drive system will become apparent from the following description of exemplary and non-limiting embodiments illustrated with reference to the accompanying drawings. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of a vehicle drive system.

[0011] Figure 2 This is a schematic cross-sectional view showing an example of a vehicle drive system.

[0012] Figure 3 This is a schematic cross-sectional view showing an example of a vehicle drive system. Detailed Implementation

[0013] Hereinafter, embodiments of the vehicle drive system will be described with reference to the accompanying drawings and using the first and second embodiments as examples. In the first and second embodiments, the structure of the power transmission mechanism is shared. Figure 1 The schematic diagram is used in both the first and second examples. Figure 2 A schematic cross-sectional view of the first example of a vehicle drive unit 100 is shown. Figure 3 A schematic cross-sectional view of the vehicle drive unit 100 of the second example is shown. Matters common to both the first and second examples will be described without distinguishing between them.

[0014] like Figures 1-3As shown, the vehicle drive unit 100 includes: a rotary motor 1 that serves as a driving force source for a pair of wheels; a first output component 2 that is driven and connected to a first wheel W1; a second output component 3 that is driven and connected to a second wheel W2; a planetary gear mechanism 4; an output differential gear device 5; and a housing 9. At least one of the first differential side gear 54 and the first drive shaft DS1 (described later) corresponds to the first output component 2, and at least one of the second differential side gear 56, the second drive shaft DS2, and the connecting shaft 30 (described later) corresponds to the second output component 3. The housing 9 houses the rotary motor 1, the planetary gear mechanism 4, and the output differential gear device 5. The first differential side gear 54, the second differential side gear 56, and the connecting shaft 30 are also housed in the housing 9. When they respectively correspond to the first output component 2 and the second output component 3, the housing 9 also houses the first output component 2 and the second output component 3. When the first drive shaft DS1 and the second drive shaft DS2 respectively correspond to the first output component 2 and the second output component 3, the housing 9 houses a portion of the first drive shaft DS1 and the second drive shaft DS2.

[0015] In this specification, "drive connection" refers to a state in which two rotating components are connected in a manner capable of transmitting driving force. This includes a state in which the two rotating components are connected in a manner that allows them to rotate as a single unit, or a state in which the two rotating components are connected via one or more transmission components in a manner capable of transmitting driving force. Such transmission components include various components that transmit rotation at constant or variable speeds, such as shafts, gear mechanisms, belts, chains, etc. Furthermore, transmission components may also include engagement devices that selectively transmit rotation and driving force, such as friction engagement devices, meshing engagement devices, etc.

[0016] In the following description, the direction along the rotation axis of the rotary electric machine 1 (the rotation axis of the rotor 12 (rotor axis A)) is designated as "axial direction L". Furthermore, one side of axial direction L is designated as "first axial side L1", and the other side of axial direction L is designated as "second axial side L2". Additionally, the direction orthogonal to rotor axis A is designated as "radial direction R". Furthermore, in radial direction R, the side of rotor axis A is designated as "inner radial side R1", and the opposite side is designated as "outer radial side R2". Finally, the direction of winding around rotor axis A is designated as "circumferential direction".

[0017] The rotary motor 1, the first output component 2, the second output component 3, the planetary gear mechanism 4, and the output differential gear device 5 are arranged coaxially. In this embodiment, they are arranged in the order of rotary motor 1, planetary gear mechanism 4, and output differential gear device 5 from the second axial side L2 toward the first axial side L1. Regarding the arrangement of the two components, "overlapping when viewed along a specific direction" means that when an imaginary line parallel to the line of sight is moved in directions orthogonal to the imaginary line, the area where the imaginary line intersects with both components exists at least partially.

[0018] like Figure 2 as well as Figure 3 As shown, in this embodiment, the housing 9 includes a peripheral wall portion 91, a first side wall portion 92, a second side wall portion 93, and a support wall portion 94.

[0019] The peripheral wall portion 91 is formed into a cylindrical shape covering the radially outer side R2 of the rotary motor 1, the first output component 2, the second output component 3, the planetary gear mechanism 4, and the output differential gear device 5. The first side wall portion 92, the second side wall portion 93, and the support wall portion 94 are each formed to extend radially R and circumferentially. In this embodiment, the first side wall portion 92 is formed to cover the axial first side L1 of the output differential gear device 5. Furthermore, the second side wall portion 93 is formed to cover the axial second side L2 of the rotary motor 1. Additionally, the support wall portion 94 is arranged between the rotary motor 1 and the planetary gear mechanism 4 along the axial L of the planetary gear mechanism 4, dividing the storage space of the rotary motor 1 and the storage space of the planetary gear mechanism 4 and the output differential gear device 5.

[0020] like Figure 2 as well as Figure 3 As shown, the peripheral wall portion 91 is formed by two shell components abutting each other along the axial direction L. Furthermore, in Figure 2 In the first example of the vehicle drive unit 100 shown, the first sidewall portion 92 is integrally formed with the peripheral wall portion 91 in a manner that blocks the axial first side L1 opening of the peripheral wall portion 91. Figure 3 In the second example of the vehicle drive unit 100 shown, the first sidewall portion 92 is formed by a component different from the component forming the peripheral wall portion 91, and abuts against the component forming the peripheral wall portion 91 from the axial first side L1 in a manner that blocks the opening of the axial first side L1 of the peripheral wall portion 91. Furthermore, as... Figure 2 as well as Figure 3 As shown, the second sidewall portion 93 is formed by a component different from the component forming the peripheral wall portion 91, and abuts against the component forming the peripheral wall portion 91 from the axial second side L2 in a manner that blocks the opening of the axial second side L2 of the peripheral wall portion 91.

[0021] The rotary motor 1 is the driving force source for the first wheel W1 and the second wheel W2. The rotary motor 1 functions as both a motor (electric motor) that receives power and generates power, and a generator (generator) that receives power and generates electricity. Specifically, the rotary motor 1 is electrically connected to an energy storage device (not shown), such as a battery or capacitor. The rotary motor 1 generates driving force (power operation) using the electricity stored in the energy storage device. Furthermore, the rotary motor 1 generates electricity and charges the energy storage device (regeneration) using the driving force transmitted from the first wheel W1 and the second wheel W2.

[0022] The rotary motor 1 is an inner rotor type rotary motor in which the rotor 12 is provided radially inner R1 of the stator 11. Furthermore, the rotary motor 1 is a rotating magnetic field type rotary motor, with the stator 11 having stator coils and the rotor 12 having permanent magnets. The rotor 12 is connected to a hollow rotor shaft 13, which passes through a connecting shaft 30, on the radially inner R1, and the rotor 12 and rotor shaft 13 rotate integrally. An input rotating member, i.e., a sun gear SG, constituting the reduction gear mechanism 4, is arranged on the outer periphery of the rotor shaft 13 in a manner that rotates integrally with the rotor shaft 13. The sun gear SG can be integrally formed with the rotor shaft 13 using the same component, or it can be formed using a different component and connected to the rotor shaft 13 by welding or the like. The rotor shaft 13 is rotatable on the first axial side L1, supported by a support wall 94 via a first rotor bearing B1, and rotatable on the second axial side L2, supported by a second side wall 93 via a second rotor bearing B2.

[0023] The planetary gear mechanism 4, which functions as a speed reducer, comprises an input rotating member (sun gear SG) that rotates integrally with the rotor shaft 13, a fixed member (first ring gear RG1) fixed to the housing 9 (a non-rotating component), an output rotating member (second ring gear RG2) that rotates integrally with the differential input member (differential housing 51), and planetary gears (first pinion PG1 and second pinion PG2). In this embodiment, the planetary gear mechanism 4 is a composite planetary gear mechanism comprising a sun gear SG, two ring gears (first ring gear RG1 and second ring gear RG2), and two planetary gears (first pinion PG1 and second pinion PG2) that are rotatable and rotate integrally with each other, supported by a common planet carrier CR. The two planetary gears rotate on their own axes about the pinion shaft fixed to the planet carrier CR, and are supported by the planet carrier CR and revolve around the rotation axis of the planetary gear mechanism 4, i.e., the rotor axis A. In this embodiment, the second pinion PG2 is formed with a diameter smaller than that of the first pinion PG1. The first pinion PG1 meshes with the sun gear SG and the first ring gear RG1. The second pinion PG2 rotates integrally with the first pinion PG1 and meshes with the second ring gear RG2. The planet carrier CR is not connected to any rotating or stationary components.

[0024] In this embodiment, the first gear ring RG1 is fixed within the housing 9 to a support wall 94 disposed between the rotary motor 1 and the planetary gear mechanism 4 along the axial direction L. That is, the non-rotating component that fixes the first gear ring RG1 is the support wall 94, and specifically the housing 9. Figure 2 as well as Figure 3 As shown, the support wall portion 94 includes a protrusion 41 that protrudes axially from the support wall portion 94 toward a first side L1. The protrusion 41 is, for example, an annular component. When viewed radially, the protrusion 41 overlaps with the first gear ring RG1 and the first pinion PG1. The protrusion 41 can be integrally formed with the support wall portion 94, or it can be formed from a component different from the support wall portion 94 and connected to the support wall portion 94 by welding or the like. In this embodiment, the protrusion 41 is also connected to the support wall portion 94 via a support member 42 extending radially R. The first gear ring RG1 is formed, for example, as a tooth (such as a spline engagement portion) on the radially inner side R1 of the protrusion 41. Therefore, at least one of the protrusion 41 and the support member 42 can be referred to as the connection between the first gear ring RG1 and the support wall portion 94.

[0025] Of course, the first gear ring RG1 may not be fixed to the support wall portion 94, but may be fixed to the inner wall surface 9a of the peripheral wall portion 91 or to a radial protrusion protruding radially R from the inner wall surface 9a of the peripheral wall portion 91. This radial protrusion may be integrally formed with the peripheral wall portion 91, or it may be formed by a component different from the peripheral wall portion 91 and connected to the support wall portion 94 by welding or the like.

[0026] The planetary carrier CR is supported radially R by the housing 9 via the planetary carrier bearing B4 in a rotatable state relative to the housing 9. The planetary carrier bearing B4 is a rolling bearing. As in the first and second examples, the planetary carrier bearing B4 supports the planetary carrier CR from the radially outer side R2. Figure 2 As shown, in the first example of the vehicle drive unit 100, the planetary carrier CR is supported from the radially outer side R2, with the pinion shaft supported by the planetary carrier CR located radially inner R1. Therefore, by configuring the planetary carrier bearing B4, the radial dimension of the planetary gear mechanism 4 can be prevented from increasing. Furthermore, in the second example of the vehicle drive unit 100, as... Figure 3 As shown, although the planetary carrier bearing B4 is arranged on the radial outer side R2 of the planetary carrier CR, as will be described later, by arranging the planetary carrier bearing B4 in the space between the inner wall surface 9a of the housing 9 and the planetary gear mechanism 4, where the radial distance R is easily increased, the expansion of the radial dimension can be suppressed.

[0027] exist Figure 2In the first example of the vehicle drive unit 100 shown, the planetary carrier bearing B4 is supported by the support wall portion 94. As described above, the protrusion 41 protrudes from the support wall portion 94 toward the axial first side L1. Furthermore, the protrusion 41 is supported by the support wall portion 94 from the radially inner side R1 via the support member 42. The planetary carrier bearing B4 is positioned to overlap with the protrusion 41 and the support member 42 when viewed radially along the radial direction R. As described above, at least one of the protrusion 41 and the support member 42 is the connection portion between the first gear ring RG1 and the support wall portion 94. Therefore, it can be said that the planetary carrier bearing B4 is positioned to overlap with the connection portion between the first gear ring RG1 and the support wall portion 94.

[0028] As described above, the second pinion PG2 is formed with a diameter smaller than that of the first pinion PG1. Therefore, in the radial direction R, the space between the second pinion PG2 and the inner wall surface 9a of the peripheral wall portion 91 of the housing 9 is more easily ensured compared to the space between the first pinion PG1 and the inner wall surface 9a. Therefore, in Figure 3 In the second example of the vehicle drive unit 100 shown, the planetary carrier CR is configured with an outer edge 43 located radially outward relative to the second ring gear RG2, which meshes with the second pinion PG2. The outer edge 43 overlaps with the second ring gear RG2 and the second pinion PG2 when viewed radially. Furthermore, the planetary carrier CR is supported at this outer edge 43 in a state where it can rotate relative to the inner wall surface 9a of the housing 9. The planetary carrier bearing B4 is positioned between the inner wall surface 9a of the housing 9 and the radial direction R of the outer edge 43 of the planetary carrier CR, and overlaps with the second ring gear RG2 when viewed radially.

[0029] Furthermore, as in the first and second examples, a configuration is shown where the planetary carrier CR is directly supported by the housing 9 (which also includes the support wall 94) via the planetary carrier bearing B4. However, a configuration in which the planetary carrier bearing B4 is supported indirectly by the housing 9 by other components such as a bracket fixed to the housing 9 is not excluded.

[0030] The output differential gear device 5 is constructed by housing a bevel gear type differential gear mechanism 50, which includes multiple differential pinions 53, a pair of differential side gears (first differential side gear 54 and second differential side gear 56), and multiple differential pinion shafts 52, inside a differential housing 51. The differential housing 51 is a differential input member that is connected to and rotates integrally with the output rotating member of the planetary gear mechanism 4, namely the second gear ring RG2. For example, the second gear ring RG2 and the differential housing 51 are integrally connected by welding.

[0031] The differential pinion 53 is supported by the differential housing 51 and is rotatable by a plurality of differential pinion shafts 52 arranged radially (e.g., cross-shaped) around the rotation axis (rotor axis A) of the differential housing 51. The first differential side gear 54 and the second differential side gear 56 mesh with each of the plurality of differential pinions 53 and rotate around the rotation axis (rotor axis A) of the differential housing 51. The first differential side gear 54 is driven to the first wheel W1 via the first drive shaft DS1. The second differential side gear 56 is driven to the second wheel W2 via the second drive shaft DS2. Furthermore, a planetary gear mechanism 4 and a rotary motor 1 are arranged between the second differential side gear 56 and the second wheel W2 along the axial direction L. Therefore, the second differential side gear 56 is connected to a connecting shaft 30 that passes through the planetary gear mechanism 4 and the rotary motor 1 along the axial direction L. The connecting shaft 30 is connected to the second drive shaft DS2, and the second drive shaft DS2 is connected to the second wheel W2. As in the first and second examples, the connecting shaft 30 is supported by the second sidewall portion 93 via the output bearing B3 so that it can rotate.

[0032] In this embodiment, with the first ring gear RG1 fixed and the planet carrier CR in a free state, the input from the sun gear SG of the planetary gear mechanism 4 is output from the second ring gear RG2. This allows for a smaller radial R dimension and the achievement of a high reduction ratio of 20 or higher. Furthermore, in this single-shaft type vehicle drive unit 100, it is easy to design a system that counteracts the meshing reaction force of the radial R gears in the planetary gear mechanism 4. By omitting the radial R bearings, torque loss in the power transmission path is easily reduced. Besides facilitating the miniaturization of the rotary motor 1, the vehicle drive unit 100 can also be configured more compactly due to the reduction in the radial R bearings.

[0033] If the radial bearing R is reduced, the centrifugal force caused by the eccentricity of the rotor 12 tends to increase when the rotor 12 of the rotary motor 1 rotates at high speed. Furthermore, due to the oscillation of the planetary gears accompanying this centrifugal force, the primary vibration of the rotor 12, as a whole, becomes significant within the vehicle drive unit 100. The vehicle drive unit 100 of this embodiment is configured to suppress the increase in torque loss in the power transmission path and reduce the primary vibration of the rotor 12.

[0034] like Figure 2 as well as Figure 3As shown, similarly in the first and second examples, the differential housing 51 is supported radially R by the housing 9 via bushing B5 in a state that allows it to rotate relative to the housing 9. Bushing B5 is positioned relative to the differential gear mechanism 50 on the side opposite to the side where the planetary gear mechanism 4 is located, i.e., on the first axial side L1, and overlaps with the differential gear mechanism 50 when viewed axially. That is, the differential housing 51 is loosely supported by the housing 9 via bushing B5 with a slight radial clearance R relative to the housing 9. Furthermore, the planet carrier CR is supported radially R by the housing 9 via planet carrier bearing B4 in a state that allows it to rotate relative to the housing 9.

[0035] The planetary carrier CR is stably supported radially R by the housing 9 via the rolling bearing, namely the planetary carrier bearing B4. Even if vibration caused by the eccentricity of the rotor 12 is transmitted to the planetary gear mechanism 4 via the first pinion PG1, the vibration of the planetary carrier CR can be suppressed. The output differential gear device 5 is supported on the planetary gear mechanism 4 side by self-centering caused by the meshing of the second gear ring RG2, and on the opposite side of the planetary gear mechanism 4 by the housing 9 via the bushing B5. Even if the output differential gear device 5 is not strongly supported radially R, since the vibration of the planetary carrier CR of the planetary gear mechanism 4 is suppressed, the transmission of vibration caused by the eccentricity of the rotor 12 to the output differential gear device 5 can also be suppressed. In the power transmission path from the rotary motor 1 to the output component, the additional rotary support structure from radially R is basically limited to the planetary carrier bearing B4, so the increase in torque loss in this power transmission path can also be suppressed.

[0036] [Summary of Implementation Methods]

[0037] The following is a brief summary of the vehicle drive unit 100 described above.

[0038] In one embodiment, the vehicle drive unit 100 includes: a rotary motor 1 having a rotor 12; a first output component 2 drivenly connected to a first wheel W1; a second output component 3 drivenly connected to a second wheel W2; a planetary gear mechanism 4 for reducing the rotation of the rotor 12; an output differential gear device 5 having a differential housing 51 and a differential gear mechanism 50 housed in the differential housing 51, and distributing the rotation transmitted from the planetary gear mechanism 4 to the differential housing 51 to the first output component 2 and the second output component 3; and a housing 9 housing the rotary motor 1, the planetary gear mechanism 4, and the output differential gear device 5. The rotary motor 1, the first output component 2, the second output component 3, the planetary gear mechanism 4, and the output differential gear device 5 are arranged coaxially. The planetary gear mechanism 4 includes a sun gear SG, a planet carrier CR, a first ring gear RG1, and a second ring gear RG2. The sun gear SG is connected to the rotor 12 in a rotating manner, and the first ring gear RG1 is connected to a non-rotating part. The second gear ring RG2 is connected to the differential housing 51 in an integral rotatable manner. The planetary carrier CR supports the first pinion PG1 and the second pinion PG2, which rotate integrally with each other, so that they can rotate. The first pinion PG1 meshes with the sun gear SG and the first gear ring RG1. The diameter of the second pinion PG2 is smaller than the diameter of the first pinion PG1, and the second pinion PG2 meshes with the second gear ring RG2. The direction along the rotation axis A of the rotor 12 is defined as the axial direction L, and the direction orthogonal to the rotation axis A is defined as the radial direction R. The differential housing 51 is supported by the housing 9 in the radial direction R via the bushing B5 in a state that allows it to rotate relative to the housing 9. The bushing B5 is arranged on the side opposite to the side where the planetary gear mechanism 4 is located and overlaps with the differential gear mechanism 50 when viewed along the axial direction. The planetary carrier CR is supported by the housing 9 in the radial direction R via the rolling bearing B4 in a state that allows it to rotate relative to the housing 9.

[0039] According to this structure, the planetary carrier supporting the first pinion PG1 and the second pinion PG2 is stably supported radially R by the housing 9 via the rolling bearing B4. Thus, even if vibrations caused by the eccentricity of the rotor 12 are transmitted via the first pinion PG1, vibrations of the planetary carrier CR can be suppressed.

[0040] The output differential gear unit 5 is supported on the planetary gear mechanism 4 side by self-centering caused by the meshing of the second ring gear RG2, and on the opposite side of the planetary gear mechanism 4 by means of bushing B5 with a slight radial clearance R relative to the housing 9. Even if the output differential gear unit 5 is not strongly supported in the radial direction R, the vibration of the planetary carrier CR is suppressed, and the vibration caused by this eccentricity is further suppressed from being transmitted to the output differential gear unit 5 via the second pinion PG2. The additional support structure in the radial direction R is basically limited to the rolling bearing B4 supporting the planetary carrier CR, so the increase in torque loss in the power transmission path from the rotary motor 1 to the output components 2 and 3 is also suppressed. Thus, according to this structure, in a single-shaft type vehicle drive unit 100 that is a reducer comprising a two-stage planetary gear mechanism 4 with a sun gear SG, two planetary gears PG1 and PG2 supported by a common planetary carrier CR, and two ring gears RG1 and RG2, the increase in torque loss in the power transmission path can be suppressed and the primary vibration of the rotor 12 can be reduced.

[0041] In addition, the vehicle drive unit 100 preferably has a housing 9 having a support wall 94 disposed between the rotary motor 1 and the planetary gear mechanism 4 along the axial direction L. The non-rotating component is the support wall 94. The rolling bearing B4 is supported by the support wall 94 and is disposed at a position that overlaps with the connection portions 41 and 42 of the first gear ring RG1 and the support wall 94 when viewed radially along the radial direction R.

[0042] According to this structure, the vibration transmission path via the rolling bearing B4 can be easily configured on the radially inner side R1. Therefore, the increase in the axial L and radial R dimensions of the vehicle drive unit 100 caused by the configuration of the rolling bearing B4 can be minimized. In addition, it is easy to reduce the diameter of the rolling bearing B4, and it is also easy to reduce the loss of rotational energy such as torque loss caused by the bearing.

[0043] In addition, the vehicle drive unit 100 preferably has a second gear ring RG2 with a diameter smaller than the first gear ring RG1, and the planetary carrier CR has an outer edge portion 43 located on the outer side R2 of the radial direction relative to the second gear ring RG2. The rolling bearing B4 is disposed between the inner wall surface 9a of the housing 9 and the radial direction R of the outer edge portion 43 and overlaps with the second gear ring RG2 when viewed radially along the radial direction R.

[0044] According to this structure, the diameter of the second gear ring RG2 is smaller than that of the first gear ring RG1. Therefore, even if the rolling bearing B4 is positioned outside the radial direction R relative to the second gear ring RG2, it is easy to suppress the increase in the radial dimension R of the vehicle drive unit 100. Furthermore, the rolling bearing B4 is positioned at a position overlapping the second gear ring RG2 when viewed radially. Therefore, by configuring the rolling bearing B4, it is easy to suppress the increase in the axial dimension L of the vehicle drive unit 100.

[0045] In addition, the vehicle drive unit 100 preferably has the second gear ring RG2 and the differential housing 51 integrally connected by welding.

[0046] According to this structure, it is easy to construct a differential housing 51 of the output differential gear device 5 that uses automatic centering caused by the meshing of the second gear ring RG2 to support the planetary gear mechanism 4.

[0047] Explanation of reference numerals in the attached figures

[0048] 1: Rotary motor, 2: First output component, 3: Second output component, 4: Planetary gear mechanism, 5: Output differential gear device, 9: Housing (non-rotating component), 9a: Inner wall surface, 12: Rotor, 41: Protrusion (connecting part), 42: Support component (connecting part), 43: Outer edge, 50: Differential gear mechanism, 51: Differential housing, 94: Support wall (non-rotating component), 100: Vehicle drive unit, A: Rotor shaft (rotor rotation axis), B4: Planetary carrier bearing (rolling bearing), B5: Bushing, CR: Planetary carrier, L: Axial, PG1: First pinion, PG2: Second pinion, R: Radial, R2: Radial outer side, RG1: First gear ring, RG2: Second gear ring, SG: Sun gear, W1: First wheel, W2: Second wheel.

Claims

1. A vehicle drive system comprising: A rotating electric motor, which has a rotor; A first output component, which is connected to the first wheel drive; The second output component is connected to the second wheel drive; A planetary gear mechanism that reduces the rotational speed of the aforementioned rotor; A differential gear device for output, comprising a differential housing and a differential gear mechanism housed within the differential housing, distributing rotation transmitted from the planetary gear mechanism to the differential housing to the first output component and the second output component; and The housing contains the aforementioned rotary motor, the aforementioned planetary gear mechanism, and the aforementioned output differential gear device. The aforementioned rotary motor, the aforementioned first output component, the aforementioned second output component, the aforementioned planetary gear mechanism, and the aforementioned output differential gear device are arranged on the same shaft. The aforementioned planetary gear mechanism includes a sun gear, a planet carrier, a first ring gear, and a second ring gear. The aforementioned sun gear is connected to the aforementioned rotor in a manner that allows it to rotate as a single unit. The aforementioned first gear ring is connected to the non-rotating component. The aforementioned second gear ring is connected to the aforementioned differential housing in a manner that allows it to rotate integrally. The aforementioned planetary carrier supports the first and second pinions, which rotate as a unit, to enable them to rotate. The aforementioned first pinion meshes with the aforementioned sun gear and the aforementioned first ring gear. The diameter of the second pinion is smaller than the diameter of the first pinion, and the second pinion meshes with the second gear ring. Let the direction along the rotation axis of the rotor be defined as the axial direction, and the direction orthogonal to the rotation axis be defined as the radial direction. The differential housing is supported radially by the housing via a bushing in a rotatable state relative to the housing. The bushing is positioned opposite the planetary gear mechanism and overlaps with the differential gear mechanism when viewed along the axial direction. The planetary carrier is supported in the radial direction by the housing in a state that allows it to rotate relative to the housing via rolling bearings.

2. The vehicle drive device according to claim 1, wherein, The aforementioned housing includes a support wall portion disposed between the aforementioned rotary motor and the aforementioned planetary gear mechanism along the aforementioned axial direction. The aforementioned non-rotating component is the aforementioned support wall portion. The aforementioned rolling bearing is supported by the aforementioned support wall portion and is positioned at a location that overlaps with the connection portion of the aforementioned first gear ring and the aforementioned support wall portion when viewed radially along the aforementioned radial direction.

3. The vehicle drive device according to claim 1, wherein, The diameter of the second gear ring is smaller than the diameter of the first gear ring. The aforementioned planetary carrier has an outer edge portion located on the outer side of the aforementioned radial direction relative to the aforementioned second gear ring. The aforementioned rolling bearing is positioned between the inner wall surface of the housing and the radial direction of the outer edge, and overlaps with the second gear ring when viewed radially along the aforementioned radial direction.

4. The vehicle drive unit according to any one of claims 1 to 3, wherein, The aforementioned second gear ring and the aforementioned differential housing are integrally connected by welding.

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