Vehicle drive device

Abstract

A vehicle drive device (100) comprises a rotary electric machine (1), a planetary gear mechanism (4), and an output differential gear device (5) that are disposed coaxially. A differential case (51) is supported with respect to a case (9) in the radial direction (R) in a state of being rotatable with respect to the case (9) via a bush (B5) disposed in a position at an opposite side of a differential gear mechanism (50) to a side at which the planetary gear mechanism (4) is positioned, the position of the bush (B5) overlapping the differential gear mechanism (50) when viewed in the axial direction (L). A carrier (CR) is supported with respect to the case (9) in the radial direction (R) in a state of being rotatable with respect to the case (9) via a rolling bearing (B4).

Description

Vehicle drive unit

[0001] The present invention relates to a vehicle drive device.

[0002] International Publication No. 2023 / 068334 discloses a so-called single-shaft vehicle drive device (100) in which a rotating electric machine (1) that serves as a driving force source for a pair of wheels (W1, 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, W2) are arranged on the same axis (reference symbols in parentheses in the background art are those of the referenced document). The planetary gear mechanism (4) is a two-stage planetary gear mechanism that shares a common carrier (CR1), and includes one sun gear (SG1), a first planetary gear (PG1) that meshes with the sun gear (SG1), a first ring gear (RG1) that meshes with the first planetary gear (PG1), a second planetary gear (PG2) that is supported by the carrier (CR1) together with the first planetary gear (PG1) and rotates integrally with the first planetary gear (PG1), and a second ring gear (RG2) that meshes with the second planetary gear (PG2). This planetary gear mechanism (4) can achieve a high reduction ratio of at least about 20 while keeping the radial dimension small when the input from the sun gear (SG1) of the planetary gear mechanism is output from the second ring gear (RG2) with the first ring gear (RG1) fixed and the carrier (CR1) free. Because this vehicle drive device (1) can easily achieve a large reduction ratio, it is easy to amplify torque and to make the rotating electric machine (1) more compact.

[0003] Furthermore, when a speed reducer using the planetary gear mechanism (4) as described above is used in a single-shaft vehicle drive device (100), it is easy to design it so as to cancel out the radial gear meshing reaction force, and torque loss in the power transmission path can be reduced by omitting radial bearings. In addition to making it easy to reduce the size of the rotating electric machine (1), not providing radial bearings makes it easy to configure the vehicle drive device (100) even more compact.

[0004] International Publication No. 2023 / 068334

[0005] As described above, when the vehicle drive system is downsized by reducing the number of radial bearings, centrifugal force due to eccentricity of the rotor of the rotating electric machine tends to increase when the rotating electric machine rotates at high speed. As a result, the planetary gears may oscillate, causing primary vibration of the rotor rotation to become noticeable throughout the vehicle drive system. To suppress such vibration, it is conceivable to radially support one or both of (i) the carrier supporting the planetary gears and (ii) the input rotating element of the differential gear unit, which rotates integrally with the second ring gear, which is the output rotating element of the planetary gear mechanism, on the case via bearings or the like. However, simply adding radial bearings or the like increases torque loss in the power transmission path. Furthermore, providing such a radial support mechanism may increase the radial dimension of the vehicle drive system.

[0006] In view of the above background, it is desirable to reduce primary vibration of rotor rotation while suppressing an increase in torque loss in the power transmission path in a single-shaft vehicle drive device equipped with a two-stage planetary gear mechanism that includes one sun gear as a reducer and two planetary gears and two ring gears supported on a common carrier.

[0007] In view of the above, a vehicle drive device includes a rotating electric machine having a rotor, a first output member drivingly connected to a first wheel, a second output member drivingly connected to a second wheel, a planetary gear mechanism that reduces the rotation of the rotor, an output differential gear device that includes a differential case and a differential gear mechanism housed in the differential case and distributes rotation transmitted from the planetary gear mechanism to the differential case to the first output member and the second output member, and a case that houses the rotating electric machine, the planetary gear mechanism, and the output differential gear device, wherein the rotating electric machine, the first output member, the second output member, the planetary gear mechanism, and the output differential gear device are coaxially arranged, and the planetary gear mechanism includes a sun gear, a carrier, a first ring gear, and a second ring gear, and the sun gear is connected to rotate integrally with the rotor, and the first ring gear is connected to a non-rotating member. the second ring gear is connected to the differential case so as to rotate integrally with it, the carrier rotatably supports a first pinion gear and a second pinion gear which rotate integrally with each other, the first pinion gear meshes with the sun gear and the first ring gear, the second pinion gear has a smaller diameter than the first pinion gear and meshes with the second ring gear, the direction along the rotation axis of the rotor is the axial direction and the direction perpendicular to the rotation axis is the radial direction, the differential case is supported in the radial direction relative to the case in a state where it can rotate freely relative to the case via a bush which is arranged on the opposite side of the differential gear mechanism from the side where the planetary gear mechanism is located and in a position which overlaps with the differential gear mechanism as viewed in the axial direction, and the carrier is supported in the radial direction relative to the case in a state where it can rotate freely relative to the case via a rolling bearing.

[0008] According to this configuration, the carrier supporting the first pinion gear and the second pinion gear is stably supported in the radial direction relative to the case via the rolling bearing. This suppresses vibration of the carrier even if vibration caused by rotor eccentricity is transmitted via the first pinion gear. The output differential gear is supported on the planetary gear mechanism side by automatic alignment due to meshing of the second ring gear, and on the opposite side of the planetary gear mechanism, is supported via a bushing with a slight radial gap relative to the case. Even though the output differential gear is not strongly supported in the radial direction, carrier vibration is suppressed, so that vibration caused by the eccentricity is suppressed from being further transmitted to the output differential gear via the second pinion gear. Because the additional support structure in the radial direction is almost entirely limited to the rolling bearing supporting the carrier, an increase in torque loss in the power transmission path from the rotating electric machine to the output member is also suppressed. Thus, according to this configuration, in a single-shaft vehicle drive device equipped with a two-stage planetary gear mechanism having one sun gear as a reducer and two planetary gears and two ring gears supported on a common carrier, it is possible to reduce primary vibration of the rotor rotation while suppressing an increase in torque loss in the power transmission path.

[0009] Further features and advantages of the vehicle drive device will become apparent from the following description of exemplary, non-limiting embodiments which are given with reference to the drawings.

[0010] Skeleton diagram of a vehicle drive device. Schematic cross-sectional view showing an example of a vehicle drive device. Schematic cross-sectional view showing an example of a vehicle drive device.

[0011] Hereinafter, two embodiments of a vehicle drive device, a first example and a second example, will be described with reference to the drawings. The first example and the second example share the same power transmission mechanism, and the skeleton diagram of FIG. 1 is common to the first example and the second example. FIG. 2 shows a schematic cross-sectional view of the vehicle drive device 100 of the first example, and FIG. 3 shows a schematic cross-sectional view of the vehicle drive device 100 of the second example. Matters common to the first example and the second example will be described without distinguishing between the first example and the second example.

[0012] As shown in FIGS. 1 to 3 , the vehicle drive system 100 includes a rotating electric machine 1 that serves as a driving force source for a pair of wheels, a first output member 2 drivingly connected to a first wheel W1, a second output member 3 drivingly connected to a second wheel W2, a planetary gear mechanism 4, an output differential gear device 5, and a case 9. At least one of a first differential side gear 54 and a first drive shaft DS1 (described later) corresponds to the first output member 2, and at least one of a second differential side gear 56, a second drive shaft DS2, and a connecting shaft 30 (described later) corresponds to the second output member 3. The case 9 houses the rotating electric machine 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 case 9. If these correspond to the first output member 2 and the second output member 3, respectively, the case 9 also houses the first output member 2 and the second output member 3. When the first drive shaft DS1 and the second drive shaft DS2 correspond to the first output member 2 and the second output member 3, respectively, the case 9 accommodates a portion of the first drive shaft DS1 and the second drive shaft DS2.

[0013] Here, in this specification, the term "driving connection" refers to a state in which two rotating elements are connected so as to be able to transmit a driving force, and includes a state in which the two rotating elements are connected so as to rotate integrally, or a state in which the two rotating elements are connected so as to be able to transmit a driving force via one or more transmission members. Such transmission members include various members that transmit rotation at the same speed or at a variable speed, such as shafts, gear mechanisms, belts, chains, etc. Note that transmission members may also include engagement devices that selectively transmit rotation and driving force, such as friction engagement devices and meshing engagement devices.

[0014] In the following description, the direction along the rotational axis of the rotating electric machine 1 (the rotational axis of the rotor 12 (rotor axis A)) is referred to as the "axial direction L." One side of the axial direction L is referred to as the "axial first side L1," and the other side of the axial direction L is referred to as the "axial second side L2." The direction perpendicular to the rotor axis A is referred to as the "radial direction R." In the radial direction R, the side of the rotor axis A is referred to as the "radial inner side R1," and the opposite side is referred to as the "radial outer side R2." The direction going around the rotor axis A is referred to as the "circumferential direction."

[0015] The rotating electric machine 1, the first output member 2, the second output member 3, the planetary gear mechanism 4, and the output differential gear device 5 are arranged coaxially. In this embodiment, the rotating electric machine 1, the planetary gear mechanism 4, and the output differential gear device 5 are arranged in this order from the second axial side L2 toward the first axial side L1. With regard to the arrangement of two elements, "overlapping when viewed in a specific direction" means that when an imaginary line parallel to the line of sight is moved in each direction perpendicular to the imaginary line, there is at least a partial area where the imaginary line intersects both of the two elements.

[0016] As shown in FIGS. 2 and 3 , in this embodiment, the case 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 .

[0017] The peripheral wall portion 91 is formed in a cylindrical shape that covers the radial outside R2 of the rotating electric machine 1, the first output member 2, the second output member 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 in the radial direction R and the circumferential direction. In this embodiment, the first side wall portion 92 is formed to cover a first axial side L1 of the output differential gear device 5. The second side wall portion 93 is formed to cover a second axial side L2 of the rotating electric machine 1. The support wall portion 94 is disposed between the rotating electric machine 1 and the planetary gear mechanism 4 in the axial direction L so as to separate the accommodation space for the rotating electric machine 1 from the accommodation spaces for the planetary gear mechanism 4 and the output differential gear device 5.

[0018] As shown in FIGS. 2 and 3 , the peripheral wall portion 91 is formed by two case members that abut in the axial direction L. In a first example of a vehicle drive device 100 shown in FIG. 2 , the first side wall portion 92 is integrally formed with the peripheral wall portion 91 so as to close the opening on the first axial side L1 of the peripheral wall portion 91. In a second example of a vehicle drive device 100 shown in FIG. 3 , the first side wall portion 92 is formed of a member separate from the member that forms the peripheral wall portion 91 and abuts against the member that forms the peripheral wall portion 91 from the first axial side L1 so as to close the opening on the first axial side L1 of the peripheral wall portion 91. Also, as shown in FIGS. 2 and 3 , the second side wall portion 93 is formed of a member separate from the member that forms the peripheral wall portion 91 and abuts against the member that forms the peripheral wall portion 91 from the second axial side L2 so as to close the opening on the second axial side L2 of the peripheral wall portion 91.

[0019] The rotating electric machine 1 is a driving force source for the first wheel W1 and the second wheel W2. The rotating electric machine 1 functions as a motor (electric motor) that receives a supply of electric power to generate power, and as a generator that receives a supply of power to generate electric power. Specifically, the rotating electric machine 1 is electrically connected to an electric storage device (not shown), such as a battery or a capacitor. The rotating electric machine 1 generates driving force using electric power stored in the electric storage device (power running). Furthermore, the rotating electric machine 1 generates electric power using driving force transmitted from the first wheel W1 and the second wheel W2 to charge the electric storage device (regeneration).

[0020] The rotating electric machine 1 is an inner rotor type rotating electric machine that includes a rotor 12 on the radially inner side R1 of the stator 11. The rotating electric machine 1 is also a rotating field type rotating electric machine, in which the stator 11 includes a stator coil and the rotor 12 includes a permanent magnet. The rotor 12 is connected to a hollow rotor shaft 13, through which a connecting shaft 30 passes, at the radially inner side R1, so that the rotor 12 and the rotor shaft 13 rotate integrally. A sun gear SG, which is an input rotating element of a planetary gear mechanism 4 that constitutes a speed reducer, is arranged on the outer periphery of the rotor shaft 13 so as to rotate integrally with the rotor shaft 13. The sun gear SG may be formed integrally with the rotor shaft 13 from the same member, or may be formed from a member separate from the rotor shaft 13 and connected to the rotor shaft 13 by welding or the like. The rotor shaft 13 is rotatably supported on the first axial side L1 via the first rotor bearing B1 relative to the support wall portion 94, and on the second axial side L2 via the second rotor bearing B2 relative to the second side wall portion 93.

[0021] The planetary gear mechanism 4, which functions as a reducer, is configured to include an input rotating element (sun gear SG) that rotates integrally with the rotor shaft 13, a fixed element (first ring gear RG1) fixed to the case 9, which is a non-rotating member, an output rotating element (second ring gear RG2) that rotates integrally with the differential input element (differential case 51), and planetary gears (first pinion gear PG1, second pinion gear PG2). In this embodiment, the planetary gear mechanism 4 is a compound planetary gear mechanism that includes one sun gear SG, two ring gears (first ring gear RG1, second ring gear RG2), and two planetary gears (first pinion gear PG1, second pinion gear PG2) that are rotatably supported on a common carrier CR and rotate integrally. The two planetary gears rotate about pinion shafts fixed to the carrier CR as their rotation axes, and are supported by the carrier CR to revolve around the rotor axis A, which is the rotation axis of the planetary gear mechanism 4. In this embodiment, the second pinion gear PG2 is formed to have a smaller diameter than the first pinion gear PG1. The first pinion gear PG1 meshes with the sun gear SG and the first ring gear RG1, and the second pinion gear PG2 rotates integrally with the first pinion gear PG1 and meshes with the second ring gear RG2. The carrier CR is not connected to any rotating or fixed elements.

[0022] In the present embodiment, the first ring gear RG1 is fixed to a support wall 94 disposed in the case 9 between the rotating electric machine 1 and the planetary gear mechanism 4 in the axial direction L. That is, the support wall 94 and the case 9 are non-rotating members that fix the first ring gear RG1. As shown in FIGS. 2 and 3 , the support wall 94 includes a protrusion 41 that protrudes from the support wall 94 toward the first axial side L1. The protrusion 41 is, for example, an annular member. The protrusion 41 overlaps the first ring gear RG1 and the first pinion gear PG1 when viewed in the radial direction. The protrusion 41 may be formed integrally with the support wall 94, or may be formed of a member separate from the support wall 94 and connected to the support wall 94 by welding or the like. In the present embodiment, the protrusion 41 is also connected to the support wall 94 via a support member 42 extending in the radial direction R. The first ring gear RG1 is formed, for example, as a tooth portion (such as a spline engagement portion) on the radially inner side R1 of the protruding portion 41. Therefore, at least one of the protruding portion 41 and the support member 42 can be said to be a connecting portion between the first ring gear RG1 and the support wall portion 94.

[0023] Naturally, the first ring gear RG1 may be fixed not to the support wall portion 94 but to the inner wall surface 9a of the peripheral wall portion 91 or to a radial protrusion that protrudes in the radial direction R from the inner wall surface 9a of the peripheral wall portion 91. This radial protrusion may also be formed integrally with the peripheral wall portion 91, or may be formed of a member separate from the peripheral wall portion 91 and connected to the support wall portion 94 by welding or the like.

[0024] The carrier CR is supported in the radial direction R relative to the case 9 via a carrier bearing B4 in a state in which it can rotate freely relative to the case 9. The carrier bearing B4 is a rolling bearing. In both the first and second examples, the carrier bearing B4 supports the carrier CR from the radially outer side R2. As shown in FIG. 2 , in the vehicle drive device 100 of the first example, the carrier CR is supported from the radially outer side R2 at a position radially inward R1 of the pinion shaft supported by the carrier CR. Therefore, by arranging the carrier bearing B4, an increase in the radial dimension of the planetary gear mechanism 4 is suppressed. In addition, in the vehicle drive device 100 of the second example, as shown in FIG. 3 , the carrier bearing B4 is arranged on the radially outer side R2 of the carrier CR. However, as described below, by arranging the carrier bearing B4 in a space where the distance in the radial direction R between the inner wall surface 9 a of the case 9 and the planetary gear mechanism 4 is likely to increase, an increase in the radial dimension is suppressed.

[0025] In the vehicle drive device 100 of the first example shown in FIG. 2 , the 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 first axial side L1. Furthermore, the protrusion 41 is supported by the support wall portion 94 from the radial inner side R1 via the support member 42. The carrier bearing B4 is disposed at a position overlapping with the protrusion 41 and the support member 42 when viewed in the radial direction R. As described above, at least one of the protrusion 41 and the support member 42 is a connecting portion between the first ring gear RG1 and the support wall portion 94. Therefore, it can be said that the carrier bearing B4 is disposed at a position overlapping with the connecting portion between the first ring gear RG1 and the support wall portion 94.

[0026] As described above, the second pinion gear PG2 has a smaller diameter than the first pinion gear PG1. Therefore, it is easier to secure a space in the radial direction R between the second pinion gear PG2 and the inner wall surface 9a of the peripheral wall portion 91 of the case 9 than between the first pinion gear PG1 and the inner wall surface 9a. For this reason, in the vehicle drive device 100 of the second example shown in FIG. 3 , the carrier CR is configured with an outer edge portion 43 located further radially outward R2 from the second ring gear RG2 that meshes with the second pinion gear PG2. The outer edge portion 43 overlaps with the second ring gear RG2 and the second pinion gear PG2 when viewed in the radial direction. The carrier CR is supported by this outer edge portion 43 in a rotatable manner relative to the inner wall surface 9a of the case 9. The carrier bearing B4 is disposed between the inner wall surface 9a of the case 9 and the outer edge portion 43 of the carrier CR in the radial direction R, at a position overlapping with the second ring gear RG2 as viewed in the radial direction.

[0027] In both the first and second examples, the carrier CR is directly supported by the case 9 (including the support wall portion 94) via the carrier bearing B4. However, this does not preclude a configuration in which the carrier bearing B4 is indirectly supported by the case 9 by being supported by a separate member such as a bracket fixed to the case 9.

[0028] The output differential gear device 5 is configured by accommodating a bevel gear type differential gear mechanism 50 including a plurality of differential pinion gears 53, a pair of differential side gears (first differential side gear 54, second differential side gear 56), and a plurality of differential pinion shafts 52 inside a differential case 51. The differential case 51 is a differential input element that is connected to a second ring gear RG2, which is an output rotation element of the planetary gear mechanism 4, and rotates integrally therewith. For example, the second ring gear RG2 and the differential case 51 are integrally connected by welding.

[0029] The differential pinion gear 53 is supported by the differential case 51 and rotatably supported by a plurality of differential pinion shafts 52 that are arranged radially (e.g., in a cross shape) around the rotation axis (rotor axis A) of the differential case 51. The first differential side gear 54 and the second differential side gear 56 mesh with the plurality of differential pinion gears 53, respectively, and rotate around the rotation axis (rotor axis A) of the differential case 51. The first differential side gear 54 is drivingly connected to the first wheel W1 via a first drive shaft DS1. The second differential side gear 56 is drivingly connected to the second wheel W2 via a second drive shaft DS2. Since the planetary gear mechanism 4 and the rotating electric machine 1 are disposed between the second differential side gear 56 and the second wheel W2 in the axial direction L, the second differential side gear 56 is connected to the connecting shaft 30 that penetrates the planetary gear mechanism 4 and the rotating electric machine 1 in 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. In both the first and second examples, the connecting shaft 30 is rotatably supported by the second side wall portion 93 via the output bearing B3.

[0030] The planetary gear mechanism 4 of this embodiment can achieve a high reduction ratio of 20 or more while keeping the dimension in the radial direction R small when the input from the sun gear SG of the planetary gear mechanism 4 is output from the second ring gear RG2 with the first ring gear RG1 fixed and the carrier CR free. Furthermore, in a single-shaft vehicle drive device 100 such as that of this embodiment, it is easy to design the planetary gear mechanism 4 so as to cancel out the gear meshing reaction force in the radial direction R, and omitting bearings in the radial direction R makes it easy to reduce torque loss in the power transmission path. In addition to making it easy to reduce the size of the rotating electric machine 1, the ease of reducing the number of bearings in the radial direction R makes it easy to configure the vehicle drive device 100 more compact.

[0031] However, if the number of bearings in the radial direction R is reduced, the centrifugal force due to eccentricity of the rotor 12 tends to increase when the rotor 12 of the rotating electric machine 1 rotates at high speed, and the oscillation of the planetary gears caused by this centrifugal force may cause the primary vibration of the rotation of the rotor 12 to become noticeable throughout the vehicle drive device 100. The vehicle drive device 100 of this embodiment is configured to reduce the primary vibration of the rotation of the rotor 12 while suppressing an increase in torque loss in the power transmission path.

[0032] 2 and 3, in both the first and second examples, the differential case 51 is supported in the radial direction R relative to the case 9 in a rotatable manner via a bush B5 that is located on the first axial side L1, which is opposite the side on which the planetary gear mechanism 4 is located relative to the differential gear mechanism 50, and that is located at a position that overlaps with the differential gear mechanism 50 as viewed in the axial direction. That is, the differential case 51 is loosely supported on the case 9 via the bush B5 with a slight gap from the case 9 in the radial direction R. In addition, the carrier CR is supported in the radial direction R relative to the case 9 via a carrier bearing B4 in a rotatable manner relative to the case 9.

[0033] Because the carrier CR is stably supported in the radial direction R relative to the case 9 via the carrier bearing B4, which is a rolling bearing, vibration of the carrier CR is suppressed even if vibration caused by eccentricity of the rotor 12 is transmitted to the planetary gear mechanism 4 via the first pinion gear PG1. The output differential gear 5 is supported by automatic alignment due to meshing of the second ring gear RG2 on the planetary gear mechanism 4 side, and is supported by the case 9 via a bush B5 on the opposite side from the planetary gear mechanism 4. Even though the output differential gear 5 is not strongly supported in the radial direction R, vibration of the carrier CR of the planetary gear mechanism 4 is suppressed, so that transmission of vibration caused by eccentricity of the rotor 12 to the output differential gear 5 is suppressed. In the power transmission path from the rotating electric machine 1 to the output member, an additional rotation support structure from the radial direction R is substantially limited to the carrier bearing B4, and an increase in torque loss in the power transmission path is also suppressed.

[0034] Summary of the embodiment The vehicle drive device (100) described above will be briefly summarized below.

[0035] In one aspect, a vehicle drive device (100) includes a rotating electric machine (1) having a rotor (12), a first output member (2) drivingly connected to a first wheel (W1), a second output member (3) drivingly connected to a second wheel (W2), a planetary gear mechanism (4) that reduces the rotation of the rotor (12), a differential gear case (51) and a differential gear mechanism (50) housed in the differential gear case (51), and an output differential gear (50) that distributes the rotation transmitted from the planetary gear mechanism (4) to the differential case (51) to the first output member (2) and the second output member (3). and a case (9) that houses the rotating electric machine (1), the planetary gear mechanism (4), and the output differential gear device (5), wherein the rotating electric machine (1), the first output member (2), the second output member (3), the planetary gear mechanism (4), and the output differential gear device (5) are coaxially arranged, the planetary gear mechanism (4) includes a sun gear (SG), a carrier (CR), a first ring gear (RG1), and a second ring gear (RG2), and the sun gear (SG) is connected to the rotor (12). The first ring gear (RG1) is connected to a non-rotating member, the second ring gear (RG2) is connected to the differential case (51) to rotate integrally, the carrier (CR) rotatably supports a first pinion gear (PG1) and a second pinion gear (PG2) which rotate integrally with each other, the first pinion gear (PG1) meshes with the sun gear (SG) and the first ring gear (RG1), and the second pinion gear (PG2) has a smaller diameter than the first pinion gear (PG1). The differential case (51) is supported in the radial direction (R) relative to the case (9) in a state where it can rotate freely relative to the case (9) via a bush (B5) that is arranged on the opposite side of the differential gear mechanism (50) from the side where the planetary gear mechanism (4) is located and in a position overlapping with the differential gear mechanism (50) when viewed in the axial direction, with the direction along the rotation axis (A) of the rotor (12) being the axial direction (L) and the direction perpendicular to the rotation axis (A) being the radial direction (R), and the carrier (CR) isThe bearing (B4) is supported in the radial direction (R) relative to the case (9) in a rotatable state relative to the case (9).

[0036] According to this configuration, the carrier supporting the first pinion gear (PG1) and the second pinion gear (PG2) is stably supported in the radial direction (R) relative to the case (9) via the rolling bearing (B4). This prevents the carrier (CR) from vibrating even if vibrations caused by eccentricity of the rotor (12) are transmitted via the first pinion gear (PG1). The output differential gear unit (5) is supported on the planetary gear mechanism (4) side by automatic alignment due to the meshing of the second ring gear (RG2), and is supported on the opposite side of the planetary gear mechanism (4) via the bush (B5) with a slight gap in the radial direction (R) relative to the case (9). Even though the output differential gear unit (5) is not strongly supported in the radial direction (R), vibrations of the carrier (CR) are suppressed, thereby preventing further transmission of vibrations caused by eccentricity to the output differential gear unit (5) via the second pinion gear (PG2). Since the additional support structure in the radial direction (R) is limited almost entirely to the rolling bearing (B4) that supports the carrier (CR), an increase in torque loss in the power transmission path from the rotating electric machine (1) to the output members (2, 3) is also suppressed. Thus, according to this configuration, in a single-shaft vehicle drive device (100) that includes a two-stage planetary gear mechanism (4) that includes one sun gear (SG) and two planetary gears (PG1, PG2) and two ring gears (RG1, RG2) supported by a common carrier (CR) as a reducer, it is possible to reduce primary vibration of the rotation of the rotor (12) while suppressing an increase in torque loss in the power transmission path.

[0037] Furthermore, it is preferable that the vehicle drive device (100) has a case (9) that includes a support wall portion (94) that is arranged between the rotating electric machine (1) and the planetary gear mechanism (4) in the axial direction (L), the non-rotating member is the support wall portion (94), and the rolling bearing (B4) is supported by the support wall portion (94) and is arranged in a position that overlaps with a connection portion (41, 42) between the first ring gear (RG1) and the support wall portion (94) when viewed radially along the radial direction (R).

[0038] According to this configuration, the vibration transmission path via the rolling bearing (B4) can be easily arranged on the radially inner side (R1). Therefore, the expansion of the axial (L) and radial (R) dimensions of the vehicle drive device (100) due to the arrangement of the rolling bearing (B4) can be kept to a minimum. In addition, the diameter of the rolling bearing (B4) can be easily reduced, and rotational energy losses such as torque loss due to the bearing can also be easily reduced.

[0039] Furthermore, in the vehicle drive device (100), it is preferable that the second ring gear (RG2) has a smaller diameter than the first ring gear (RG1), the carrier (CR) has an outer edge portion (43) located on the outside (R2) of the radial direction (R) relative to the second ring gear (RG2), and the rolling bearing (B4) is located between the inner wall surface (9a) of the case (9) and the outer edge portion (43) in the radial direction (R) and is positioned so as to overlap with the second ring gear (RG2) when viewed radially along the radial direction (R).

[0040] According to this configuration, because the second ring gear (RG2) has a smaller diameter than the first ring gear (RG1), even if the rolling bearing (B4) is disposed radially outwardly of the second ring gear (RG2), it is easy to prevent the radial dimension of the vehicle drive device (100) from increasing in size in the radial direction (R). Furthermore, because the rolling bearing (B4) is disposed at a position overlapping with the second ring gear (RG2) as viewed in the radial direction, it is easy to prevent the axial dimension of the vehicle drive device (100) from increasing in size by disposing the rolling bearing (B4).

[0041] In addition, in the vehicle drive device (100), it is preferable that the second ring gear (RG2) and the differential case (51) are integrally connected by welding.

[0042] According to this configuration, it is easy to construct a structure in which the differential case (51) of the output differential gear device (5) is supported on the planetary gear mechanism (4) side by using automatic alignment due to meshing of the second ring gear (RG2).

[0043] 1: rotating electric machine, 2: first output member, 3: second output member, 4: planetary gear mechanism, 5: output differential gear device, 9: case (non-rotating member), 9a: inner wall surface, 12: rotor, 41: protrusion (connecting portion), 42: support member (connecting portion), 43: outer edge portion, 50: differential gear mechanism, 51: differential case, 94: support wall portion (non-rotating member), 100: vehicle drive device, A: rotor axis (rotational axis of rotor), B4: carrier bearing (rolling bearing), B5: bush, CR: carrier, L: axial direction, PG1: first pinion gear, PG2: second pinion gear, R: radial direction, R2: radially outer side (radially outer side), RG1: first ring gear, RG2: second ring gear, SG: sun gear, W1: first wheel, W2: second wheel

Claims

1. A vehicle drive device comprising: a rotating electric machine having a rotor; a first output member drivingly connected to a first wheel; a second output member drivingly connected to a second wheel; a planetary gear mechanism for reducing the rotation of the rotor; an output differential gear device comprising a differential case and a differential gear mechanism housed in the differential case, and distributing rotation transmitted from the planetary gear mechanism to the differential case to the first output member and the second output member; and a case for housing the rotating electric machine, the planetary gear mechanism, and the output differential gear device, wherein the rotating electric machine, the first output member, the second output member, the planetary gear mechanism, and the output differential gear device are coaxially arranged, the planetary gear mechanism comprises a sun gear, a carrier, a first ring gear, and a second ring gear, the sun gear is connected to rotate integrally with the rotor, the first ring gear is connected to a non-rotating member, and the second ring gear is connected to rotate integrally with the differential case, a differential case supported in the radial direction relative to the case in a state where it can rotate freely relative to the case via a bush that is located on the opposite side of the differential gear mechanism from the side where the planetary gear mechanism is located and in a position that overlaps with the differential gear mechanism as viewed in the axial direction; and a vehicle drive device in which the carrier rotatably supports a first pinion gear and a second pinion gear that rotate integrally with each other, the first pinion gear meshing with the sun gear and the first ring gear, the second pinion gear having a smaller diameter than the first pinion gear and meshing with the second ring gear, a direction along a rotation axis of the rotor is defined as an axial direction, and a direction perpendicular to the rotation axis is defined as a radial direction, the differential case is supported in the radial direction relative to the case in a state where it can rotate freely relative to the case via a bush that is located on the opposite side of the differential gear mechanism from the side where the planetary gear mechanism is located and in a position that overlaps with the differential gear mechanism as viewed in the axial direction, and the carrier is supported in the radial direction relative to the case in a state where it can rotate freely relative to the case via a rolling bearing.

2. A vehicle drive device as described in claim 1, wherein the case includes a support wall portion arranged axially between the rotating electric machine and the planetary gear mechanism, the non-rotating member is the support wall portion, and the rolling bearing is supported by the support wall portion and is arranged in a position overlapping with the connection portion between the first ring gear and the support wall portion when viewed radially along the radial direction.

3. A vehicle drive device as described in claim 1, wherein the second ring gear has a smaller diameter than the first ring gear, the carrier has an outer edge portion located radially outward from the second ring gear, and the rolling bearing is positioned radially between the inner wall surface of the case and the outer edge portion, at a position overlapping with the second ring gear when viewed radially along the radial direction.

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

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