JP2024065832A - Vehicle drive device - Google Patents

Abstract

A planetary gear mechanism that constitutes a reduction gear is miniaturized, thereby making a vehicle drive device more compact.
[Solution] The reducer 3 is a planetary gear mechanism including a sun gear SG, a first ring gear RG1, a second ring gear RG2, and a planetary gear PG. A first axial support member 71 is disposed between the planetary gear PG and an intermediate support portion 8 of a case 9 in the axial direction L, supporting a load in the axial direction L while allowing relative rotation between the planetary gear PG and the intermediate support portion 8, and a second axial support member 72 is disposed between the planetary gear PG and a differential gear mechanism 5 in the axial direction L, supporting a load in the axial direction L while allowing relative rotation between the planetary gear PG and the differential gear mechanism 5. The planetary gear PG is supported from a first axial side L1 by the intermediate support portion 8 via the first axial support member 71, and is supported from a second axial side L2 by the differential gear mechanism 5 via the second axial support member 72.
[Selected Figure] Figure 1

Description

The present invention relates to a vehicle drive device.

JP 2019-74205 A discloses a vehicle drive device (100) including a rotating electric machine (2), a reduction gear (3), a differential gear mechanism (4), and a case (1) that houses them (reference symbols in parentheses in the Background Art are those of the reference document). The rotating electric machine (2), the reduction gear (4), and the differential gear mechanism (4) are arranged coaxially. In this vehicle drive device (100), the reduction gear (3) is configured to include two planetary gear mechanisms (31, 32). The first planetary gear mechanism (31) is drivingly connected to the rotating electric machine (2), the second planetary gear mechanism (32) is drivingly connected to the differential gear mechanism (4), and the first planetary gear mechanism (31) and the second planetary gear mechanism (32) are drivingly connected. In the first planetary gear mechanism (31), the first sun gear (S31) is the input element, the first ring gear (R1) is the fixed non-rotating element, and the first carrier (C31) is the output element. In the second planetary gear mechanism (32), the second sun gear (S32) is the input element, the second ring gear (R2) is the fixed non-rotating element, and the second carrier (C32) is the output element.

JP 2019-74205 A

In recent years, there has been a demand for miniaturizing vehicle drive devices, and various vehicle drive devices have been proposed in which each rotating element is arranged on a single shaft, as described above. In order to realize a reduction gear arranged on a single shaft, it is preferable to configure the reduction gear with a planetary gear mechanism, as described above. A planetary gear mechanism as a reduction gear often includes at least an input element, an output element, and a non-rotating element, as described above. When bearings that support these rotating elements are included, the number of parts in the reduction gear tends to increase, and there is a limit to how much the vehicle drive device can be miniaturized.

In light of the above background, it is desirable to miniaturize the planetary gear mechanism that constitutes the reducer in a vehicle drive device in which a rotating electric machine, a reduction gear, and a differential gear mechanism are arranged coaxially, thereby making the vehicle drive device even more compact.

In consideration of the above-mentioned problems, a vehicle drive device includes a rotating electric machine having a rotor, a rotor shaft that rotates integrally with the rotor, a reducer that reduces the rotation of the rotor shaft, a differential gear mechanism that distributes the driving force from the rotating electric machine transmitted to a differential input element via the reducer to a pair of wheels, and a case that accommodates the rotating electric machine, the reducer, and the differential gear mechanism, in which the direction along the rotation axis of the rotor is defined as the axial direction, one side in the axial direction is defined as the axial first side, and the other side in the axial direction is defined as the axial second side, and the rotating electric machine, the reducer, and the differential gear mechanism are arranged coaxially with each other in the order described above from the axial first side to the axial second side, and the reducer includes a sun gear connected to rotate integrally with the rotor, a first ring gear fixed to the case, and a second ring gear arranged on the axial second side of the first ring gear and connected to rotate integrally with the differential input element. The planetary gear mechanism includes a sun gear and a planetary gear, the planetary gear includes a first gear portion that meshes with the sun gear and the first ring gear, and a second gear portion that rotates integrally with the first gear portion and meshes with the second ring gear. The case includes an intermediate support portion disposed between the rotating electric machine and the reducer in the axial direction. A first axial support member is disposed between the planetary gear and the intermediate support portion in the axial direction, which supports a load in the axial direction while allowing relative rotation between the planetary gear and the intermediate support portion. A second axial support member is disposed between the planetary gear and the differential gear mechanism in the axial direction, which supports a load in the axial direction while allowing relative rotation between the planetary gear and the differential gear mechanism. The planetary gear is supported from the first axial side by the intermediate support portion via the first axial support member, and is supported from the second axial side by the differential gear mechanism via the second axial support member.

According to this configuration, the planetary gear is supported on both radial sides by the sun gear and the first ring gear, and is supported on both axial sides between the intermediate support part of the case and the differential gear mechanism via a pair of axial support members. Therefore, even though the planetary gear mechanism as a reducer does not have a carrier, the planetary gear can be properly supported in a rotatable state. And, according to this configuration, it is possible to eliminate the carrier, the bearing for rotatably supporting the carrier, and the bearing for supporting the planetary gear relatively rotatably with respect to the carrier, which are necessary in a general planetary gear mechanism. This allows the reducer to be made smaller and the torque transmission efficiency in the reducer to be improved.

In addition, in consideration of the above-mentioned problems, a vehicle drive device is provided as a vehicle drive device having, as another configuration, a drive force source, an input member drivingly connected to the drive force source, a reducer that reduces the rotation of the input member, a differential gear mechanism that distributes the drive force from the drive force source transmitted to a differential input element via the reducer to a pair of wheels, and a case that accommodates the reducer and the differential gear mechanism, in which the direction along the rotation axis of the input member is defined as the axial direction, one side in the axial direction is defined as the axial first side, and the other side in the axial direction is defined as the axial second side, and the input member, the reducer, and the differential gear mechanism are arranged coaxially with each other in the order described from the axial first side to the axial second side, and the reducer includes a sun gear connected to rotate integrally with the input member, a first ring gear fixed to the case, and a second ring gear arranged on the axial second side of the first ring gear and connected to rotate integrally with the differential input element. The planetary gear mechanism includes a sun gear and a planetary gear, the planetary gear includes a first gear portion that meshes with the sun gear and the first ring gear, and a second gear portion that rotates integrally with the first gear portion and meshes with the second ring gear. A first axial support member is disposed between the planetary gear and a first support portion disposed on the first axial side of the planetary gear, which supports a load in the axial direction while allowing relative rotation between the planetary gear and the first support portion. A second axial support member is disposed between the planetary gear and a second support portion disposed on the second axial side of the planetary gear, which supports a load in the axial direction while allowing relative rotation between the planetary gear and the second support portion. The planetary gear is supported from the first axial side by the first support portion via the first axial support member, and is supported from the second axial side by the second support portion via the second axial support member.

According to this configuration, the planetary gear is supported from both radial sides by the sun gear and the first ring gear, and is supported from both axial sides between the first support part and the second support part via a pair of axial support members. Therefore, even though the planetary gear mechanism as a reducer does not have a carrier, the planetary gear can be properly supported in a rotatable state. And, according to this configuration, it is possible to eliminate the carrier, the bearing for rotatably supporting the carrier, and the bearing for supporting the planetary gear relatively rotatably with respect to the carrier, which are necessary in a general planetary gear mechanism. This allows the reducer to be made smaller and the torque transmission efficiency in the reducer to be improved.

Further features and advantages of the vehicle drive system will become apparent from the following description of the embodiments, which are illustrated with reference to the drawings.

FIG. 2 is an axial cross-sectional view of a vehicle drive device (first vehicle drive device); Skeleton diagram of a vehicle drive system Top view of thrust washer Side view of thrust washer FIG. 2 is an axial cross-sectional view of a second vehicle drive device; FIG. 11 is an axial cross-sectional view of a third vehicle drive device; FIG. 13 is an axial cross-sectional view of a fourth vehicle drive device;

Embodiments of the vehicle drive device will be described below with reference to the drawings. Four forms of the vehicle drive device will be described below in order. When distinguishing between the forms, they will be referred to as the first vehicle drive device 100A, the second vehicle drive device 100B, the third vehicle drive device 100C, and the fourth vehicle drive device 100D, respectively. When no distinction is made, they will be simply referred to as the vehicle drive device 100.

In this specification, "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. In addition, the transmission members may also include engagement devices that selectively transmit rotation and driving force, such as friction engagement devices and meshing engagement devices. However, when referring to each rotating element of a planetary gear mechanism as "driving connection," it refers to a state in which multiple rotating elements in the planetary gear mechanism are connected to each other without passing through other rotating elements. In addition, in this specification, "rotating integrally" refers to rotating integrally regardless of whether they are separable or not. In other words, multiple members that rotate integrally may be integrally formed from the same member, or may be made of different members and integrated by welding, spline connection, etc.

As shown in Figures 1 and 2, the vehicle drive device 100 includes a rotating electric machine 1 with a rotor 12, a rotor shaft 2 that rotates integrally with the rotor 12, a reduction gear 3 that reduces the rotation of the rotor shaft 2, a differential gear mechanism 5 that distributes the driving force from the rotating electric machine 1 transmitted to a differential input element (e.g., a differential support member 50) via the reduction gear 3 to a pair of wheels W, and a case 9 that houses the rotating electric machine 1, the reduction gear 3, and the differential gear mechanism 5. The rotating electric machine 1 corresponds to the driving force source for the wheels W, and the rotor shaft 2 corresponds to an input member that is drivingly connected to the driving force source.

In the following description, the direction along the rotation axis of the rotor 12 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". In this embodiment, the rotating electric machine 1, the reduction gear 3, and the differential gear mechanism 5 are arranged coaxially in the order described from the axial first side L1 to the axial second side L2. Therefore, the axial first side L1 is the side on which the rotating electric machine 1 is arranged relative to the reduction gear 3, and the axial second side L2 is the side on which the differential gear mechanism 5 is arranged relative to the reduction gear 3. The vehicle drive device 100 of this embodiment has a single shaft configuration, and the shaft (rotation axis X) on which the rotating electric machine 1, the reduction gear 3, and the differential gear mechanism 5 are arranged is the rotation axis X of the vehicle drive device 100, and is also the rotation axis X of the rotating electric machine 1, the reduction gear 3, and the differential gear mechanism 5. In addition, the direction perpendicular to the rotation axis X of the rotor 12 is referred to as the "radial direction R". In the radial direction R, the side of the rotation axis X of the rotor 12 is the "radial inner side R1," and the opposite side is the "radial outer side R2."

As shown in FIG. 1, the case 9 includes a first case member 9A, a second case member 9B, and a cover member 9C. The first case member 9A is a case member that generally houses the rotating electric machine 1 inside, and the second case member 9B is a member that generally houses the gear mechanism (the reduction gear 3 and the differential gear mechanism 5) inside. The second case member 9B is a bottomed cylindrical member with a through hole formed at the bottom through which the drive shaft (the second drive shaft DS2 shown in FIG. 2) passes. The first case member 9A is a cylindrical member, and a continuous storage section is formed by abutting an opening of the second case member 9B (an opening opening on the axial first side L1) and an opening of the first case member 9A on the second case member 9B side (an opening opening on the axial second side L2). In addition, the cover member 9C has a through hole through which the drive shaft (first drive shaft DS1 shown in FIG. 2) passes, and abuts against an opening on the first axial side L1 of the first case member 9A to close the opening.

The case 9 also includes an intermediate support portion 8 disposed between the rotating electric machine 1 and the reducer 3 in the axial direction L. In this embodiment, the intermediate support portion 8 is configured as a separate member from the second case member 9B, but may be formed integrally with the second case member 9B.

The rotating electric machine 1 functions as a driving force source for the pair of wheels W. The rotating electric machine 1 is electrically connected to an electricity storage device (not shown) such as a battery or a capacitor, and has the function of a motor (electric motor) that receives a supply of electric power to generate motive power, and the function of a generator (electric power generator) that receives a supply of motive power to generate electric power. The rotating electric machine 1 generates driving force by running using the electric power stored in the electricity storage device, and also generates electricity using the driving force transmitted from the pair of wheels W to charge the electricity storage device.

As shown in Figs. 1 and 2, the stator 11 of the rotating electric machine 1 has a cylindrical stator core 11a. The stator core 11a is fixed to the case 9 (here, the peripheral wall portion of the first case member 9A). The rotor 12 of the rotating electric machine 1 has a cylindrical rotor core 12a. The rotor core 12a is connected to the rotor shaft 2 so as to rotate integrally with the rotor shaft 2, and is supported by a pair of rotor bearings B2 so as to be rotatable relative to the stator core 11a. In this application, "rotating integrally" means that multiple elements rotate integrally, regardless of whether the multiple elements are separable or inseparable.

In this embodiment, the rotating electric machine 1 is an inner rotor type rotating electric machine. Therefore, the rotor core 12a is arranged radially inward R1 with respect to the stator core 11a. Also, the rotor shaft 2 is arranged radially inward R1 with respect to the rotor core 12a.

In this embodiment, the rotating electric machine 1 is a rotating field type rotating electric machine. Therefore, the stator coil 11b is wound around the stator core 11a, and coil end portions 11e are formed that protrude from the stator core 11a on both sides in the axial direction L. Although not shown, a permanent magnet is arranged in the rotor core 12a.

In this embodiment, the rotor shaft 2 is formed in a cylindrical shape coaxial with the rotor core 12a. The rotor shaft 2 is arranged so as to protrude from the rotor core 12a on both sides in the axial direction L. In this embodiment, the portion of the rotor shaft 2 protruding from the rotor core 12a to the first axial side L1 is rotatably supported on the cover member 9C of the case 9 via one rotor bearing B2. In addition, the portion of the rotor shaft 2 protruding from the rotor core 12a to the second axial side L2 is arranged so as to pass through the intermediate support portion 8 of the case 9 in the axial direction L, and is rotatably supported on the intermediate support portion 8 via the other rotor bearing B2.

As described later, a sun gear SG of the planetary gear mechanism constituting the reduction gear 3 is arranged on the outer periphery of the second axial side L2 of the rotor shaft 2 so as to rotate integrally with the rotor shaft 2. In this embodiment, the sun gear SG is formed integrally with the rotor shaft 2. In addition, although this embodiment illustrates an example in which the rotor shaft 2 and the sun gear SG are made of the same material, they may be made of separate materials and joined by welding or the like. The sun gear SG is an input element of the reduction gear 3.

The differential gear mechanism 5 is a bevel gear type differential gear mechanism. The differential gear mechanism includes a pinion gear 51 and a side gear 52, both of which are bevel gears. The pinion gear 51 is supported by the differential support member 50 and rotatably supported by a pinion shaft 55 that is arranged to extend along the radial direction R. The pinion shaft 55 rotates integrally with the differential support member 50, and the pinion gear 51 is configured to be rotatable (spin) about the pinion shaft 55 and rotatable (revolve) about the rotation axis X of the differential support member 50.

In this embodiment, the multiple pinion shafts 55 are arranged radially around the rotation axis of the differential support member 50 (for example, four pinion shafts 55 are arranged in a cross shape when viewed in the axial direction L). A pinion gear 51 is attached to each of the multiple pinion shafts 55.

The side gear 52 includes a first side gear 53 and a second side gear 54, and is arranged as a pair spaced apart in the axial direction L. The first side gear 53 is arranged on a first axial side L1 relative to the pinion shaft 55. The second side gear 54 is arranged on a second axial side L2 relative to the pinion shaft 55. The first side gear 53 and the second side gear 54 mesh with each of the multiple pinion gears 51. The first side gear 53 and the second side gear 54 are arranged to rotate around the rotation axis X of the differential support member 50.

As shown in FIG. 1, in this embodiment, the first side gear 53 is connected to a connecting shaft 6 extending along the axial direction L. As shown in FIG. 2, the connecting shaft 6 is connected to rotate integrally with the first drive shaft DS1 that is drivingly connected to the first wheel W1, which is the wheel W on the first axial side L1. Therefore, the first side gear 53 is drivingly connected to the first wheel W1 via the connecting shaft 6. As shown in FIG. 1, the connecting shaft 6 is arranged to penetrate the radial inner side R1 in the axial direction L with respect to the rotating electric machine 1, the rotor shaft 2, and the reducer 3. Also, as shown in FIG. 2, the second side gear 54 is connected to rotate integrally with the second drive shaft DS2 that is drivingly connected to the second wheel W2, which is the wheel W on the second axial side L2.

That is, the differential gear mechanism 5 includes a shaft member (pinion shaft 55) supported by a differential input element (differential support member 50) and arranged to extend along the radial direction R, a first bevel gear (pinion gear 51) supported rotatably by the shaft member, and a pair of second bevel gears (side gears 52) arranged on both sides of the shaft member in the axial direction L and meshing with the first bevel gear. Each of the pair of second bevel gears is drivingly connected to the wheels W. One of the pair of second bevel gears, the target second bevel gear (first side gear 53), is connected to rotate integrally with a connecting shaft 6 arranged to penetrate the inside of the radial direction R relative to the rotor shaft 2.

The reduction gear 3 is configured as a planetary gear mechanism including an input element that rotates integrally with the rotor shaft 2, a fixed element fixed to the case 9, an output element that rotates integrally with the differential input element (differential support member 50), and a planetary gear PG. This planetary gear mechanism is a composite planetary gear mechanism including one sun gear SG, two ring gears (first ring gear RG1, second ring gear RG2), and a planetary gear PG that includes two gear portions (first gear portion G1, second gear portion G2) that rotate integrally. Specifically, the reduction gear 3 is a planetary gear mechanism including a sun gear SG connected to rotate integrally with the rotor 12, a first ring gear RG1 fixed to the case 9, a second ring gear RG2 disposed on the second axial side L2 relative to the first ring gear RG1 and connected to rotate integrally with the differential input element, and a planetary gear PG. A plurality of planetary gears PG are arranged in the circumferential direction around the sun gear SG. For example, three or four planetary gears PG are arranged at equal intervals in the circumferential direction. Each planetary gear PG includes a first gear portion G1 that meshes with the sun gear SG and the first ring gear RG1, and a second gear portion G2 that rotates integrally with the first gear portion G1 and meshes with the second ring gear RG2. In this embodiment, the second gear portion G2 is formed with a smaller diameter than the first gear portion G1.

The reducer 3 of this embodiment does not have a carrier that is provided in a typical planetary gear mechanism to support the planetary gear PG. In this embodiment, the sun gear SG is the input element, the first ring gear RG1 is the fixed element, and the second ring gear RG2 is the output element.

In this embodiment, the planetary gear PG is formed from the same material. However, the two materials may be integrated by welding or the like. As described above, in this embodiment, the reducer 3 formed from the planetary gear mechanism does not have a carrier that supports the planetary gear PG. In other words, the reducer 3 is a planetary gear mechanism that includes a sun gear SG, a first ring gear RG1, a second ring gear RG2, and a planetary gear PG, and does not have a carrier that rotates while supporting the planetary gear PG. The planetary gear PG is supported in the radial direction R by the first gear portion G1 meshing with the sun gear SG and the first ring gear RG1. In addition, the planetary gear PG is disposed between the differential gear mechanism 5 and the intermediate support portion 8, and is supported in the axial direction L by the differential gear mechanism 5 and the intermediate support portion 8.

Specifically, a first axial support member 71 is disposed between the planetary gear PG and the intermediate support portion 8 in the axial direction L, which supports the load in the axial direction L while allowing the relative rotation between the planetary gear PG and the intermediate support portion 8. In addition, a second axial support member 72 is disposed between the planetary gear PG and the differential gear mechanism 5 in the axial direction L, which supports the load in the axial direction L while allowing the relative rotation between the planetary gear PG and the differential gear mechanism 5. The planetary gear PG is supported from the first axial side L1 by the intermediate support portion 8 via the first axial support member 71, and is supported from the second axial side L2 by the differential gear mechanism 5 via the second axial support member 72. In the first vehicle drive device 100A, the planetary gear PG is supported from the second axial side L2 by the first side gear 53 (target second bevel gear). The intermediate support portion 8 corresponds to the first support portion disposed on the first axial side L1 with respect to the planetary gear PG. The differential gear mechanism 5 corresponds to a second support part that is disposed on the second axial side L2 relative to the planetary gear PG. The first axial support member 71 is disposed between the planetary gear PG and the first support part in the axial direction L. The second axial support member 72 is disposed between the planetary gear PG and the second support part in the axial direction L.

Thus, in this embodiment, even though the planetary gear mechanism serving as the reducer 3 does not have a carrier, the planetary gear PG can be appropriately supported in a freely rotatable state. This makes it possible to eliminate the carrier, the bearings for rotatably supporting the carrier, and the bearings for supporting the planetary gear relatively rotatably with respect to the carrier, which are necessary in a typical planetary gear mechanism. This makes it possible to reduce the size of the reducer 3 and also to increase the torque transmission efficiency in the reducer 3.

When the planetary gear mechanism includes a carrier that rotates while supporting the planetary gears, it is necessary to include bearings for rotatably supporting the carrier, and needle bearings within the carrier that rotatably support the planetary gears inside the carrier. When no carrier is included as in this embodiment, the members that constitute the carrier, the bearings that support the carrier, and needle bearings within the carrier are not required, and it is possible to reduce component costs and assembly costs. In addition, since no space is required for arranging the carrier members, it is easy to miniaturize the vehicle drive device 100. Furthermore, since friction through bearings and the like is eliminated, power transmission losses in the reducer 3 are reduced, and transmission efficiency can be improved.

In this embodiment, the first axial support member 71 and the second axial support member 72 are thrust washers 7. FIG. 3 is a plan view of the thrust washer 7, and FIG. 4 is a side view thereof. The thrust washer 7 has an annular body 75 and protrusions 76 bent from multiple points on the radial inside of the body 75 in a direction perpendicular to the body 75. In this embodiment, four protrusions 76 are provided at 90 degree intervals. As shown in FIG. 1, the first axial support member 71 is fixed to the intermediate support member 8 by engaging the protrusions 76 with the engagement hole 4 formed in the intermediate support member 8. The second axial support member 72 is fixed to the first side gear 53 by engaging the protrusions 76 with the engagement hole 4 formed in the first side gear 53. In this embodiment, the thrust washer 7 is a plated metal plate, but may be made of resin.

Here, an example is shown in which the first axial support member 71 and the second axial support member 72 are configured with a thrust washer 7. However, this does not preclude an embodiment in which the first axial support member 71 and the second axial support member 72 are configured with a thrust bearing having a rotating body such as a cylindrical roller member or ball. The same is true for the second vehicle drive device 100B, the third vehicle drive device 100C, and the fourth vehicle drive device 100D described below.

The case 9, specifically the second case member 9B, is provided with a second side support portion 92 arranged on the second axial side L2 relative to the differential gear mechanism 5. The second side support portion 92 is formed on the inner wall of the bottom of the second case member 9B, which is formed in a bottomed cylindrical shape. A third axial support member 73 is arranged between the differential gear mechanism 5 and the second side support portion 92 in the axial direction L, which supports the load in the axial direction L while allowing relative rotation between the differential gear mechanism 5 and the second side support portion 92. In this embodiment, the third axial support member 73 is a thrust bearing. The differential gear mechanism 5 is supported from the second axial side L2 by the second side support portion 92 via the third axial support member 73.

With this configuration, the differential gear mechanism 5 is supported from the second axial side L2 relative to the case 9, so that the planetary gear PG can be properly supported from the second axial side L2 via the differential gear mechanism 5 and the second axial support member 72.

As described above, the differential gear mechanism 5 is supported from the axial second side L2 by the third axial support member 73, and the movement to the axial second side L2 is restricted. The movement of the differential gear mechanism 5 to the axial first side L1 is restricted by the connecting shaft 6 and the connecting bearing B6 described later. The connecting shaft 6 is formed with a shaft side support portion 65 protruding from the outer circumferential surface to the radially outer side R2. The first side gear 53 (target second bevel gear) abuts against the surface of the axial second side L2 of the shaft side support portion 65, thereby restricting the movement of the differential gear mechanism 5 to the axial first side L1. In this example, the shaft side support portion 65 is disposed adjacent to the axial first side L1 with respect to the connection portion (here, the spline connection portion) with the first side gear 53 on the outer circumferential surface of the connecting shaft 6. Also, in this example, the shaft side support portion 65 is disposed on the radial inner side R1 with respect to the second gear portion G2, and is disposed at a position overlapping with the second gear portion G2 when viewed in the radial direction along the radial direction R.

The first side gear 53 (target second bevel gear) is connected to the connecting shaft 6 arranged to penetrate the radial inner side R1 relative to the rotor shaft 2 so as to rotate integrally with the connecting shaft 6, and is supported from the axial first side L1 by the shaft side support portion 65 provided on the connecting shaft 6. The connecting shaft 6 is also supported from the axial first side L1 by the case 9 via the connecting bearing B6 (first bearing). The connecting bearing B6 is, for example, a thrust ball bearing. As described above, the planetary gear PG is supported from the axial second side L2 by the differential gear mechanism 5 via the second axial support member 72. More specifically, the planetary gear PG is supported from the axial second side L2 by the first side gear 53 (target second bevel gear) via the second axial support member 72. In other words, the second axial support member 72 is disposed between the planetary gear PG and the side gear 52 (second bevel gear) in the axial direction L, and the first side gear 53 (target second bevel gear) is supported from the first axial side L1 by the connecting shaft 6. In this embodiment, the movement of the differential gear mechanism 5 toward the first axial side L1 is restricted by the first side gear 53 (target second bevel gear) abutting against the surface facing the second axial side L2 of the shaft side support portion 65 provided to protrude radially outward from the connecting shaft 6.

With this configuration, a portion of the axial load acting on the first side gear 53 (target second bevel gear) can be supported by the connecting shaft 6. This restricts the first side gear 53 (target second bevel gear) from moving to the first axial side L1, so that the axial load between the first side gear 53 (target second bevel gear) and the planetary gear PG can be kept small. This makes it easier to improve the durability of the second axial support member 72 that is arranged axially between the first side gear 53 (target second bevel gear) and the planetary gear PG, and reduces torque loss due to sliding.

The sun gear SG, first ring gear RG1, and second ring gear RG2 are helical gears. The angle of these helical teeth is preferably set so that the resultant force of the axial load that the planetary gear PG receives from the sun gear SG, the axial load that the planetary gear PG receives from the first ring gear RG1, and the axial load that the planetary gear PG receives from the second ring gear RG2 becomes zero.

By setting the angle of the helical teeth in this way, the axial load acting between the planetary gear PG and the pair of axial support members (first axial support member 71, second axial support member 72) can be kept small. This makes it easier to improve the durability of the pair of axial support members and reduces torque loss due to sliding.

Next, the second vehicle drive device 100B, which is a second embodiment of the vehicle drive device 100, will be described with reference to FIG. 5. Descriptions of configurations similar to those of the first vehicle drive device 100A described above will be omitted where appropriate.

As with the first vehicle drive device 100A, the sun gear SG of the reduction gear 3 is integrally formed with the rotor shaft 2 so as to rotate integrally with the rotor shaft 2. As described above, the rotor shaft 2 is supported in the axial direction L and radial direction R by a pair of rotor bearings B2 (second bearings). Therefore, the sun gear SG is supported in the axial direction L and radial direction R via the rotor bearings B2 (second bearings). As shown in FIG. 5, a third bearing B3 is disposed between the first side gear 53 (target second bevel gear) of the differential gear mechanism 5 and the sun gear SG of the reduction gear 3 in the axial direction L. In other words, the differential gear mechanism 5 is supported from the axial first side L1 by the sun gear SG via the third bearing B3. In this embodiment, the third bearing B3 is a thrust bearing.

With this configuration, a portion of the axial load acting on the differential gear mechanism 5 can be supported by the sun gear SG. This restricts the differential gear mechanism 5 from moving to the first axial side L1, so the axial load between the differential gear mechanism 5 and the planetary gear PG can be kept small. This makes it easier to improve the durability of the second axial support member 72 and reduces torque loss due to sliding.

Next, the third vehicle drive device 100C, which is a third embodiment of the vehicle drive device 100, will be described with reference to FIG. 6. Descriptions of configurations similar to those of the first vehicle drive device 100A and the second vehicle drive device 100B described above will be omitted as appropriate.

In the third vehicle drive device 100C, the differential support member 50 of the differential gear mechanism 5 constitutes a differential case. A plurality of pinion shafts 55 are supported by the differential case, and a plurality of pinion gears 51 and a pair of side gears 52 are housed in the internal space of the differential case. In addition, in the third vehicle drive device 100C, the second ring gear RG2 of the reduction gear 3, which rotates integrally, and the differential case (differential support member 50), which is a differential input element, are integrally connected. A fourth bearing B4 is disposed between the second ring gear RG2 and the first ring gear RG1 in the axial direction L. In other words, the second ring gear RG2 is supported from the first axial side L1 via the fourth bearing B4 by the first ring gear RG1 fixed to the case 9. In this embodiment, the fourth bearing B4 is a thrust bearing.

With this configuration, a portion of the axial load acting on the differential input element (differential support member 50) can be supported by the first ring gear RG1. This restricts the differential gear mechanism 5 from moving toward the first axial side L1, thereby keeping the axial load between the differential gear mechanism 5 and the planetary gear PG small. This makes it easier to improve the durability of the second axial support member 72 and reduces torque loss due to sliding.

Next, the fourth vehicle drive device 100D, which is a fourth embodiment of the vehicle drive device 100, will be described with reference to FIG. 7. Descriptions of configurations similar to those of the first vehicle drive device 100A, the second vehicle drive device 100B, and the third vehicle drive device 100C described above will be omitted as appropriate.

As with the third vehicle drive device 100C, in the fourth vehicle drive device 100D, the differential support member 50 of the differential gear mechanism 5 constitutes a differential case. A plurality of pinion shafts 55 are supported by the differential case, and a plurality of pinion gears 51 and a pair of side gears 52 are housed in the internal space of the differential case. In the fourth vehicle drive device 100D, the second ring gear RG2 of the reduction gear 3, which rotates integrally, and the differential case (differential support member 50), which is the differential input element, are also integrally connected. In the fourth vehicle drive device 100D, the second ring gear RG2 is supported from the axial first side L1 by the case 9 (second case member 9B) via the fourth bearing B4. In this embodiment, the fourth bearing B4 is a thrust ball bearing that supports loads in the radial direction R and the axial direction L.

This configuration allows the case 9 to support a portion of the axial load acting on the differential input element (differential support member 50). This restricts the differential gear mechanism 5 from moving toward the first axial side L1, thereby keeping the axial load between the differential gear mechanism 5 and the planetary gear PG small. This makes it easier to improve the durability of the second axial support member 72 and reduces torque loss due to sliding.

That is, according to the third vehicle driving device 100C and the fourth vehicle driving device 100D, a portion of the axial load acting on the differential input element (differential support member 50) can be supported by the case 9 or the first ring gear RG1. This restricts the differential gear mechanism 5 from moving toward the first axial side L1, so that the axial load between the differential gear mechanism 5 and the planetary gear PG can be kept small. This makes it easier to improve the durability of the second axial support member 72 and reduces torque loss due to sliding.

Other embodiments
Other embodiments will be described below. Note that the configurations of the embodiments described below are not limited to being applied independently, and may be applied in combination with the configurations of other embodiments as long as no contradiction occurs.

(1) In the above, the sun gear SG, the first ring gear RG1, and the second ring gear RG2 are illustrated as helical gears. However, this does not prevent these gears from being spur gears.

(2) In the above, the differential gear mechanism 5 is supported from the second axial side L2 by the second side support portion 92 of the case 9 via the third axial support member 73. Specifically, the second side gear 54 (see FIG. 1 and FIG. 5) and the differential support member 50 (see FIG. 6 and FIG. 7) as the differential case are supported from the second axial side L2 by the second side support portion 92 via the third axial support member 73. However, this does not prevent the differential gear mechanism 5 from being supported from the second axial side L2 in another manner. For example, the differential support member 50 may be supported on the case 9 (e.g., the second side support portion 92 or the inner peripheral surface of the second case member 9B) via a thrust bearing or the like so that movement to the second axial side L2 is restricted.

(3) In the above, for example, referring to FIG. 5, a configuration in which the differential gear mechanism 5 (first side gear 53 integrally connected to the connecting shaft 6) is supported by the sun gear SG from the first axial side L1 via the third bearing B3 has been exemplified. Also, referring to FIG. 7, a configuration in which the differential gear mechanism 5 (differential support member 50, which is a differential input element integrally connected to the second ring gear RG2) is supported by the case 9 from the first axial side L1 via the fourth bearing B4 has been exemplified. These are examples of configurations in which a rotating member having a differential rotation is supported via a bearing, and the member supporting the differential gear mechanism 5 is not limited to the sun gear SG and the case 9. For example, in the configuration exemplified in FIG. 7, instead of the fourth bearing B4, a bearing may be disposed between the differential support member 50 and the connecting shaft 6, and the differential gear mechanism 5 (differential support member 50) may be supported by the connecting shaft 6 from the first axial side L1 via the bearing.

(4) In the above, an example was given of a vehicle drive device 100 including a rotating electric machine 1, a rotor shaft 2, a reduction gear 3, a differential gear mechanism 5, and a case 9 housing the rotor shaft 2, the reduction gear 3, and the differential gear mechanism 5, in which the reduction gear 3 is configured as a planetary gear mechanism without a carrier. However, the vehicle drive device 100 thus including the four elements of a sun gear SG, a first ring gear RG1, a second ring gear RG2, and a planetary gear PG and including a reduction gear 3 configured as a planetary gear mechanism without a carrier that rotatably supports the planetary gear PG is not limited to the form exemplified above. That is, the vehicle drive device 100 may include a drive source, an input member that is drivingly connected to the drive source, a reduction gear 3 that reduces the rotation of the input member, a differential gear mechanism 5 that distributes the drive force from the drive source that is transmitted to the differential input element via the reduction gear 3 to a pair of wheels W, and a case 9 that houses the reduction gear 3 and the differential gear mechanism 5. Note that it is sufficient that at least a portion of the input member is housed in the case 9.

The driving force source is not limited to the rotating electric machine 1 as described above, but may be an internal combustion engine such as a gasoline engine, a diesel engine, or an LPG engine, or an internal combustion engine and a transmission mechanism. An input member is disposed between the driving force source and the reducer, including when the driving force source is the rotating electric machine 1. When the driving force source is the rotating electric machine 1, the rotor shaft 2 corresponds to the input member. When the driving force source is an internal combustion engine, for example, the crankshaft corresponds to the input member. When the driving force source is an internal combustion engine and a transmission, the transmission output member or a rotating member drivingly connected to the transmission output member corresponds to the input member.

Therefore, the vehicle drive device 100 includes a driving force source, an input member that is drivingly connected to the driving force source, a reduction gear 3 that reduces the rotation of the input member, a differential gear mechanism 5 that distributes the driving force from the driving force source that is transmitted to the differential input element via the reduction gear 3 to a pair of wheels W, and a case 9 that houses the reduction gear 3 and the differential gear mechanism 5. The axial direction L is a direction along the rotation axis X of the input member. The reduction gear 3 is a planetary gear mechanism that includes a sun gear SG that is connected to rotate integrally with the input member, a first ring gear RG1 fixed to the case 9, a second ring gear RG2 that is disposed on the second axial side L2 relative to the first ring gear RG1 and is connected to rotate integrally with the differential input element, and a planetary gear PG.

This planetary gear mechanism has four elements: a sun gear SG, a first ring gear RG1, a second ring gear RG2, and a planetary gear PG, but does not have a carrier that rotatably supports the planetary gear PG. Therefore, a first axial support member 71 that supports a load in the axial direction L while allowing relative rotation between the planetary gear PG and the first support portion is arranged between the planetary gear PG and the axial direction L between a first support portion arranged on the axial first side L1 of the planetary gear PG. In addition, a second axial support member 72 that supports a load in the axial direction L while allowing relative rotation between the planetary gear PG and the second support portion is arranged between the planetary gear PG and the axial second side L2 of the planetary gear PG.

In the embodiment exemplified above with reference to Figures 1 to 7, the intermediate support portion 8 corresponds to the first support portion. However, the first support portion is not limited to the intermediate support portion 8 as long as it is a member arranged on the first axial side L1 with respect to the planetary gear PG, and may be, for example, the sun gear SG, the first ring gear RG1, or a portion of the case 9 other than the intermediate support portion 8. In the embodiment exemplified above with reference to Figures 1 to 7, the differential gear mechanism 5 corresponds to the second support portion. However, the second support portion is not limited to the differential gear mechanism 5 as long as it is a member arranged on the second axial side L2 with respect to the planetary gear PG, and may be, for example, the second ring gear RG2.

1: rotating electric machine (driving force source), 2: rotor shaft (input shaft), 3: reducer, 5: differential gear mechanism (first support part), 6: connecting shaft, 8: intermediate support part (second support part), 9: case, 12: rotor, 50: differential support member (differential input element), 51: pinion gear (first bevel gear), 52: side gear (second bevel gear), 53: first side gear (target second bevel gear), 65: shaft side support part, 71: first axial support member, 72: second axial support member, 73: third axial support member, 92: second side support part, 100: vehicle drive device, 100A: first vehicle drive device (vehicle drive device), 100 B: second vehicle drive device (vehicle drive device), 100C: third vehicle drive device (vehicle drive device), 100D: fourth vehicle drive device (vehicle drive device), B2: rotor bearing (second bearing), B3: third bearing, B4: fourth bearing, B6: connecting bearing (first bearing), G1: first gear part, G2: second gear part, L: axial direction, L1: first axial side, L2: second axial side, PG: planetary gear, R: radial direction, R1: radial inner side (radial inner side), R2: radial outer side (radial outer side), RG1: first ring gear, RG2: second ring gear, SG: sun gear, W: wheel, X: rotation axis

Claims (7)

A rotating electric machine having a rotor;
a rotor shaft that rotates integrally with the rotor;
a reducer that reduces the rotation speed of the rotor shaft;
a differential gear mechanism that distributes a driving force from the rotating electric machine, which is transmitted to a differential input element via the speed reducer, to a pair of wheels;
A vehicle drive device including the rotating electric machine, the reduction gear, and a case that accommodates the differential gear mechanism,
A direction along the rotation axis of the rotor is defined as an axial direction, one side in the axial direction is defined as an axial first side, and the other side in the axial direction is defined as an axial second side,
the rotating electric machine, the reduction gear, and the differential gear mechanism are coaxially arranged in the order described above from the first axial side to the second axial side,
the reducer is a planetary gear mechanism including: a sun gear connected to rotate integrally with the rotor; a first ring gear fixed to the case; a second ring gear disposed on the second axial side of the first ring gear and connected to rotate integrally with the differential input element; and a planetary gear;
the planetary gear includes a first gear portion that meshes with the sun gear and the first ring gear, and a second gear portion that rotates integrally with the first gear portion and meshes with the second ring gear,
the case includes an intermediate support portion disposed between the rotating electric machine and the reducer in the axial direction,
a first axial support member is disposed between the planetary gear and the intermediate support portion in the axial direction, the first axial support member supporting a load in the axial direction while allowing relative rotation between the planetary gear and the intermediate support portion,
a second axial support member is disposed between the planetary gear and the differential gear mechanism in the axial direction, the second axial support member supporting a load in the axial direction while allowing relative rotation between the planetary gear and the differential gear mechanism,
a planetary gear that is supported from the first axial side by the intermediate support portion via the first axial support member, and that is supported from the second axial side by the differential gear mechanism via the second axial support member. the case includes a second side support portion disposed on the second axial side with respect to the differential gear mechanism,
a third axial support member is disposed between the differential gear mechanism and the second support portion in the axial direction, the third axial support member supporting a load in the axial direction while allowing relative rotation between the differential gear mechanism and the second support portion,
2. The vehicle drive device according to claim 1, wherein the differential gear mechanism is supported from the second axial side by the second support portion via the third axial support member. A direction perpendicular to the rotation axis is a radial direction,
the differential gear mechanism comprises: a shaft member supported by the differential input element and arranged to extend along the radial direction; a first bevel gear rotatably supported by the shaft member; and a pair of second bevel gears arranged separately on both sides of the shaft member in the axial direction and meshing with the first bevel gear,
Each of the pair of second bevel gears is drivingly connected to the wheel;
a target second bevel gear, which is one of the pair of second bevel gears, is connected to a connecting shaft arranged to penetrate the inner side in the radial direction with respect to the rotor shaft so as to rotate integrally with the connecting shaft, and is supported from the first axial direction side by a shaft side support portion provided on the connecting shaft,
the connecting shaft is supported by the case from the first axial side via a first bearing,
the second axial support member is disposed between the planetary gear and the second bevel gear in the axial direction,
The vehicle drive device according to claim 1 or 2, wherein the symmetric second bevel gear is supported from the first axial side by the connecting shaft. A direction perpendicular to the rotation axis is a radial direction,
the sun gear is supported in the axial direction and the radial direction via a second bearing,
3. The vehicle drive device according to claim 1, wherein the differential gear mechanism is supported from the first axial side by the sun gear via a third bearing. the differential input element and the second ring gear are integrally connected,
3 . The vehicle drive device according to claim 1 , wherein the second ring gear is supported from the first axial side by the case or the first ring gear via a fourth bearing. the sun gear, the first ring gear, and the second ring gear are helical gears,
3. The vehicle drive device according to claim 1, wherein the angles of the helical teeth of the sun gear, the first ring gear, and the second ring gear are set so that a resultant force of an axial load that the planetary gear receives from the sun gear, an axial load that the planetary gear receives from the first ring gear, and an axial load that the planetary gear receives from the second ring gear is zero. A driving force source;
an input member drivingly connected to the driving force source;
a reducer that reduces the rotation speed of the input member;
a differential gear mechanism that distributes the driving force from the driving force source, which is transmitted to the differential input element via the reducer, to a pair of wheels;
a case that houses the reduction gear and the differential gear mechanism,
A direction along the rotation axis of the input member is defined as an axial direction, one side in the axial direction is defined as an axial first side, and the other side in the axial direction is defined as an axial second side,
the input member, the reduction gear, and the differential gear mechanism are coaxially arranged in the order described above from the first axial side to the second axial side,
the reducer is a planetary gear mechanism including: a sun gear connected to rotate integrally with the input member; a first ring gear fixed to the case; a second ring gear disposed on the second axial side of the first ring gear and connected to rotate integrally with the differential input element; and a planetary gear;
the planetary gear includes a first gear portion that meshes with the sun gear and the first ring gear, and a second gear portion that rotates integrally with the first gear portion and meshes with the second ring gear,
a first axial support member is disposed between the planetary gear and a first support portion disposed on a first side in the axial direction with respect to the planetary gear, the first axial support member supporting a load in the axial direction while allowing relative rotation between the planetary gear and the first support portion,
a second axial support member is disposed between the planetary gear and a second support portion disposed on a second axial side of the planetary gear, the second axial support member supporting a load in the axial direction while allowing relative rotation between the planetary gear and the second support portion,
a vehicle drive device, wherein the planetary gear is supported from the first axial side by the first support portion via the first axial support member, and is supported from the second axial side by the second support portion via the second axial support member.

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