Drive transmission device for vehicle

Abstract

To provide a technology for easily and properly supporting a first gear when a power transmission mechanism of a drive transmission device for a vehicle includes the first gear and a second gear meshing with the first gear.SOLUTION: A power transmission mechanism of a vehicular drive transmission device includes a first gear G1 and a second gear G1 meshing with the first gear G2. The first gear side G1 is disposed on the axial first side L1 with respect to the target wall portion 51 of the case 5, and is rotatably supported with respect to the case 5 by the target bearings 60. The target bearings 60 include a plurality of rolling elements 70 and an inner race 74 that supports the plurality of rolling elements 70 from the R1 portion on the inner side in the radial direction R. The inner race 74 includes a rolling element support portion 75 that supports the plurality of rolling elements 70, and a boss portion 76 that supports the rolling element support portion 75 and is formed so as to extend toward the L2 on the second side in the axial direction with respect to the plurality of rolling elements 70. The boss portion 76 is fixed to the target wall portion 51 of the case 5.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a drive transmission device for a vehicle that includes an input member that is drivingly connected to a drive source, an output member that is drivingly connected to a wheel, a power transmission mechanism that transmits driving force between the input member and the output member, and a case that houses the power transmission mechanism. [Background technology]

[0002] An example of such a vehicle drive transmission device is disclosed in International Publication No. 2023 / 095822 (Patent Document 1). Hereinafter, in the description of the background art, reference numerals in parentheses refer to those in Patent Document 1. In the vehicle drive transmission device of Patent Document 1, a power transmission mechanism (3) includes a first gear (32) and a second gear (33) that meshes with the first gear (32). As shown in FIG. 1 of Patent Document 1, a case (9) that houses the power transmission mechanism (3) includes a support wall portion (SW), and a bearing support portion (SWa) that protrudes toward a first axial side (L1), which is one side in the axial direction (L). The first gear (32) is disposed on the first axial side (L1) of the support wall portion (SW) and is rotatably supported relative to the bearing support portion (SWa) by a first support bearing (B2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2023 / 095822 Summary of the Invention [Problem to be solved by the invention]

[0004] Although not explicitly stated in Patent Document 1, it can be understood from FIG. 1 of the document that in the vehicle drive transmission device of Patent Document 1, the support portion (referred to as a bearing support portion in Patent Document 1) that supports the first gear is integrally formed from the same material as the wall portion of the case (referred to as a support wall portion in Patent Document 1). The support structure for the first gear is required to have sufficient strength and rigidity to adequately support the load acting on the first gear due to meshing with the second gear. However, when the support portion that supports the first gear is integrally formed from the same material as the wall portion of the case, the material for the support portion cannot be freely selected. Therefore, depending on other constraints on the support structure (such as dimensions and shape), it may be difficult to ensure the appropriate strength and rigidity of the support structure for the first gear, making it difficult to adequately support the first gear.

[0005] Therefore, when a power transmission mechanism of a vehicle drive transmission device includes a first gear and a second gear that meshes with the first gear, it is desirable to realize a technology that makes it easy to appropriately support the first gear. [Means for solving the problem]

[0006] A vehicle drive transmission device according to the present disclosure includes an input member drivingly connected to a drive source, an output member drivingly connected to a wheel, a power transmission mechanism that transmits driving force between the input member and the output member, and a case that houses the power transmission mechanism, wherein the power transmission mechanism includes a first gear and a second gear that meshes with the first gear, and wherein a direction along a rotation axis of the first gear is defined as an axial direction, a direction perpendicular to the rotation axis is defined as a radial 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, and the first gear is disposed on the axial first side with respect to a target wall portion of the case, and The target bearing is rotatably supported on the case by an elephant bearing, and the target bearing comprises a plurality of rolling elements arranged radially inward of a first gear tooth portion, which is a tooth portion of the first gear, and at a position overlapping with the first gear tooth portion when viewed radially along the radial direction, and an inner race supporting the plurality of rolling elements from the radially inside, the inner race comprising a rolling element support portion supporting the plurality of rolling elements, and a boss portion supporting the rolling element support portion and formed to extend toward the second axial side relative to the plurality of rolling elements, and the boss portion is fixed to the target wall portion of the case.

[0007] According to this configuration, the inner race of the target bearing is structured so that the rolling element support portion, which supports the rolling elements, is supported by a boss portion fixed to the target wall portion of the case, so the first gear, which is subjected to a radial load due to meshing with the second gear, can be appropriately supported by the case. Furthermore, according to this configuration, because the boss portion supporting the rolling element support portion is a separate member from the case, the boss portion can be made of a material suitable for supporting the first gear. Therefore, it is easy to ensure appropriate strength and rigidity for the support structure for the first gear.

[0008] As described above, according to this configuration, when the power transmission mechanism of the vehicle drive transmission device includes a first gear and a second gear that meshes with the first gear, it becomes easier to appropriately support the first gear.

[0009] Further features and advantages of the vehicle drive transmission device will become apparent from the following description of the embodiments, which is given with reference to the drawings. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a skeleton diagram of a vehicle drive transmission device according to a first embodiment; [Figure 2] 1 is a cross-sectional view of a portion of a vehicle drive transmission device according to a first embodiment; [Figure 3] 10 is a cross-sectional view of a portion of a vehicle drive transmission device according to a second embodiment. [Figure 4] 10 is a cross-sectional view of a portion of a vehicle drive transmission device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] [First embodiment] A first embodiment of a vehicle drive transmission device will be described with reference to the drawings (FIGS. 1 and 2).

[0012] In this specification, the term "driving connection" refers to a state in which two rotating elements are connected to each other so as to be able to transmit a driving force, and includes a state in which the two rotating elements are connected to rotate integrally, or a state in which the two rotating elements are connected to each other 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, and chains. 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. However, when the term "driving connection" is used to refer to each rotating element of a planetary gear mechanism, it refers to a state in which the rotating elements are connected to each other without passing through other rotating elements of the planetary gear mechanism.

[0013] In this specification, the term "rotating electric machine" is used as a concept that includes motors, generators, and motor-generators that function as both motors and generators as needed. Furthermore, in this specification, with regard to the arrangement of two elements, "overlapping when viewed from 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.

[0014] As shown in FIG. 1, the vehicle drivetrain 100 includes an input member 30 drivingly connected to a drive source 1, an output member 20 drivingly connected to a wheel W, a power transmission mechanism 2 that transmits driving force between the input member 30 and the output member 20, and a case 5 that houses the power transmission mechanism 2. The vehicle drivetrain 100 transmits the driving force of the drive source 1 to the wheel W to run a vehicle (a vehicle equipped with the vehicle drivetrain 100). In this embodiment, the drive source 1 is a rotating electric machine. However, the drive source 1 may be a drive source other than a rotating electric machine (for example, an internal combustion engine). The input member 30 may also be configured to be drivingly connected to a plurality of drive sources 1 (for example, a rotating electric machine and an internal combustion engine).

[0015] The rotating electric machine as the driving source 1 is electrically connected to an electricity storage device such as a battery or a capacitor. The rotating electric machine is electrically connected to the electricity storage device, for example, via an inverter. The rotating electric machine generates driving force by running using the electric power stored in the electricity storage device. The rotating electric machine also generates electricity using driving force transmitted to the rotating electric machine (for example, driving force transmitted from the wheels W), thereby charging the electricity storage device.

[0016] The rotating electric machine serving as the driving source 1 includes a rotor 10 that is drivingly connected to an input member 30. The input member 30 is connected to the rotor 10 so as to rotate integrally with the rotor 10, for example. Note that when the driving source 1 is an internal combustion engine, the input member 30 may be connected to the driving source 1 via a damper or the like.

[0017] The rotating electric machine serving as the driving source 1 further includes a stator 11. The stator 11 is fixed to the case 5. The rotor 10 is supported by the case 5 so as to be rotatable relative to the stator 11. In this embodiment, the rotating electric machine is a rotating field type rotating electric machine, in which a permanent magnet is provided in the rotor 10 (specifically, a rotor core that is the core of the rotor 10), and a coil is wound around the stator 11 (specifically, a stator core 11a that is the core of the stator 11). The portion of the coil that protrudes from the stator core 11a forms a coil end portion 11b.

[0018] In this embodiment, the power transmission mechanism 2 is configured to transmit driving force between an input member 30 and a plurality of output members 20. Specifically, the vehicle drive transmission device 100 includes, as the output members 20, a first output member 21 drivingly connected to a first wheel W1 and a second output member 22 drivingly connected to a second wheel W2. The first wheel W1 and the second wheel W2 form a pair of left and right wheels W. The power transmission mechanism 2 is configured to transmit driving force between the input member 30 and two output members 20 (i.e., the first output member 21 and the second output member 22). Note that the power transmission mechanism 2 may also be configured to transmit driving force between the input member 30 and one output member 20.

[0019] The power transmission mechanism 2 includes a first gear G1 and a second gear G2 that meshes with the first gear G1. Here, the rotational axis of the first gear G1 is referred to as the "first axis A1," and the rotational axis of the second gear G2 is referred to as the "second axis A2." The direction along the first axis A1 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 second axis A2 is an axis parallel to the first axis A1. Therefore, the axial direction L is also a direction along the second axis A2. Furthermore, the direction perpendicular to the first axis A1 is referred to as the "radial direction R," the inside of the radial direction R (the side approaching the first axis A1) is referred to as the "radial inner side R1," and the outside of the radial direction R (the side moving away from the first axis A1) is referred to as the "radial outer side R2."

[0020] The elements of the power transmission mechanism 2 are arranged along a plurality of axes (for example, two or three axes) including a first axis A1 and a second axis A2. In this embodiment, the power transmission mechanism 2 has a two-axis configuration in which the elements are arranged along two axes (A1, A2). As shown in FIG. 1 , in this embodiment, the power transmission mechanism 2 includes a planetary gear mechanism 3 that transmits the rotation of an input member 30 to a first gear G1, and a differential gear mechanism 4 that distributes the rotation of a second gear G2 to a first output member 21 and a second output member 22. In this example, the planetary gear mechanism 3 is configured to reduce the rotation of the input member 30 and transmit it to the first gear G1. The input member 30 and the planetary gear mechanism 3 are arranged coaxially with the first gear G1 (i.e., on the first axis A1), and the first output member 21, the second output member 22, and the differential gear mechanism 4 are arranged coaxially with the second gear G2 (i.e., on the second axis A2).

[0021] In this embodiment, of the two gears that mesh with each other, the gear that is arranged on the upstream side of the power transmission path (toward the input member 30) is the first gear G1, and the gear that is arranged on the downstream side of the power transmission path (toward the output member 20) is the second gear G2, but the gear that is arranged on the downstream side of the power transmission path may be the first gear G1, and the gear that is arranged on the upstream side of the power transmission path may be the second gear G2. Also, any two gears that are provided in the power transmission mechanism 2 and mesh with each other may be the first gear G1 and the second gear G2. 1, if the elements of the power transmission mechanism 2 are arranged along three axes, namely, an input-side axis on which the input member 30 is arranged, an output-side axis on which the output member 20 is arranged, and an intermediate axis different from the input-side axis and the output-side axis, the gear arranged on the intermediate axis and the gear arranged on the input-side axis or the output-side axis and meshing with the gear can be referred to as the first gear G1 and the second gear G2. In this case, for example, a counter gear mechanism is arranged on the intermediate axis, and the gear included in the counter gear mechanism is referred to as the first gear G1 or the second gear G2.

[0022] The planetary gear mechanism 3 can be a planetary gear mechanism of any structure, such as a single-pinion type or a double-pinion type. The planetary gear mechanism 3 illustrated in FIG. 1 will now be described. The planetary gear mechanism 3 includes a sun gear SG, a carrier CR, and a ring gear RG. The carrier CR rotatably supports a first pinion gear PG1 and a second pinion gear PG2, which rotate integrally with each other, via a pinion shaft PS. The first pinion gear PG1 meshes with the sun gear SG, and the second pinion gear PG2 meshes with the ring gear RG. The second pinion gear PG2 is disposed on a first axial side L1 relative to the first pinion gear PG1. The second pinion gear PG2 has a smaller diameter than the first pinion gear PG1.

[0023] The sun gear SG is drivingly connected to the input member 30. Here, the sun gear SG is connected to the input member 30 so as to rotate integrally therewith. In the example shown in FIG. 2, the sun gear SG is formed integrally with the input member 30, and more specifically, is formed on the outer periphery of the input member 30. The ring gear RG is fixed to a non-rotating member (in this example, the case 5). The carrier CR is drivingly connected to the first gear G1. Here, the carrier CR is connected to the first gear G1 so as to rotate integrally therewith.

[0024] The differential gear mechanism 4 may be a differential gear mechanism of any structure, such as a bevel gear type or a planetary gear type. The differential gear mechanism 4 illustrated in FIG. 1 will now be described. The differential gear mechanism 4 includes a differential case 40, a first side gear 41, a second side gear 42, a pinion shaft 43, and a pinion gear 44. The differential case 40 is configured to rotate about a second axis A2. The pinion gear 44 is supported by the pinion shaft 43 that rotates integrally with the differential case 40, and rotates (spins) about the pinion shaft 43 and also rotates (revolves) about the second axis A2. The first side gear 41 and the second side gear 42 mesh with the pinion gear 44 and rotate about the second axis A2. The first side gear 41 is disposed on a first axial side L1 relative to the pinion shaft 43, and the second side gear 42 is disposed on a second axial side L2 relative to the pinion shaft 43.

[0025] The differential case 40 is drivingly connected to the second gear G2. Here, the differential case 40 is connected to the second gear G2 so as to rotate integrally with the second gear G2. The first side gear 41 is drivingly connected to the first output member 21, and the second side gear 42 is drivingly connected to the second output member 22. Here, the first side gear 41 is connected to the first output member 21 so as to rotate integrally with the first output member 21, and the second side gear 42 is connected to the second output member 22 so as to rotate integrally with the second output member 22. For example, a portion of the member constituting the first side gear 41 to which a connecting shaft JS (described later) is connected constitutes the first output member 21, and a portion of the member constituting the second side gear 42 to which a second drive shaft DS2 (described later) is connected constitutes the second output member 22.

[0026] In this embodiment, the vehicle on which the vehicle drive transmission device 100 is mounted is provided with a first drive shaft DS1 drivingly connected to a first wheel W1 and a second drive shaft DS2 drivingly connected to a second wheel W2. The drive shafts (DS1, DS2) are connected to the wheels W via, for example, constant velocity joints. The first output member 21 is connected to the first drive shaft DS1 so as to rotate integrally with the first drive shaft DS1, and the second output member 22 is connected to the second drive shaft DS2 so as to rotate integrally with the second drive shaft DS2. In the example shown in FIG. 1, the first output member 21 is connected to the first drive shaft DS1 via a connecting shaft JS.

[0027] As shown in FIG. 2, the case 5 includes a housing chamber S that houses the power transmission mechanism 2. The case 5 includes a peripheral wall portion 50 that covers the power transmission mechanism 2 from the radially outer side R2, and the housing chamber S is formed by being surrounded by the peripheral wall portion 50 from the radially outer side R2. The case 5 also includes a target wall portion 51. For example, the target wall portion 51 may be a wall portion that separates the inside and outside of the case 5 (e.g., an axial end wall disposed at an end of the case 5 in the axial direction L) or a wall portion that separates the inside of the case 5 into multiple sections (e.g., an intermediate wall disposed at an intermediate portion of the case 5 in the axial direction L). In this embodiment, the target wall portion 51 is a wall portion that separates the inside and outside of the case 5, and specifically, is an axial end wall disposed at the end of the case 5 on the second axial side L2.

[0028] The support structure of the first gear G1 will be described below with reference to Fig. 2. The first gear G1 is disposed on a first axial side L1 relative to the target wall portion 51 of the case 5. The first gear G1 is rotatably supported relative to the case 5 by a target bearing 60. The first gear G1 is supported from a radially inner side R1 by the target bearing 60. Specifically, the first gear G1 has a cylindrical portion G1b on the outer periphery of which a first gear tooth portion G1a (the tooth portion of the first gear G1) is formed, and the target bearing 60 is disposed so as to contact the inner circumferential surface of the cylindrical portion G1b. The first gear tooth portion G1a meshes with a second gear tooth portion G2a (the tooth portion of the second gear G2).

[0029] The symmetric bearing 60 includes a plurality of rolling elements 70 and an inner race 74 that supports the rolling elements 70 from the radially inner side R1. The rolling elements 70 are spaced apart in the circumferential direction (the direction orbiting the first axis A1). The symmetric bearing 60 also includes an outer race 73 that supports the rolling elements 70 from the radially outer side R2. In this embodiment, the symmetric bearing 60 is a ball bearing, and the rolling elements 70 are balls. The symmetric bearing 60 may be a single-row bearing or a double-row bearing. In this embodiment, the symmetric bearing 60 is a double-row angular bearing that includes two raceways: a first raceway on a first axial side L1 and a second raceway on a second axial side L2. The rolling elements 70 include a plurality of first rolling elements 71 arranged in the first raceway and a plurality of second rolling elements 72 arranged in the second raceway.

[0030] The multiple rolling elements 70 are arranged on the radially inner side R1 of the first gear tooth portion G1a and at positions overlapping with the first gear tooth portion G1a as viewed in the radial direction along the radial direction R. When the multiple rolling elements 70 include multiple first rolling elements 71 and multiple second rolling elements 72, as in the target bearing 60 of this embodiment, at least one of the multiple first rolling elements 71 and the multiple second rolling elements 72 (both in the illustrated example) is arranged on the radially inner side R1 of the first gear tooth portion G1a and at positions overlapping with the first gear tooth portion G1a as viewed in the radial direction. In the illustrated example, the entirety of each of the multiple first rolling elements 71 overlaps with the first gear tooth portion G1a as viewed in the radial direction, and a portion of each of the multiple second rolling elements 72 on the axial first side L1 overlaps with the first gear tooth portion G1a as viewed in the radial direction.

[0031] The outer race 73 includes an outer ring raceway forming member 73a, and an outer ring raceway surface is formed on the inner peripheral surface of the outer ring raceway forming member 73a. In this embodiment, a double-row (two-row) outer ring raceway surface is formed on the inner peripheral surface of one outer ring raceway forming member 73a. In this embodiment, the portion of the outer race 73 that supports the multiple rolling elements 70 (here, the outer ring raceway forming member 73a) is a separate member from the first gear G1. Note that at least a portion of the portion of the outer race 73 that supports the multiple rolling elements 70 may also be configured to be integrally formed with the first gear G1.

[0032] The outer ring raceway forming member 73a is attached to the first gear G1 (specifically, to the inner peripheral surface of the cylindrical portion G1b) so that relative movement to both sides in the axial direction L with respect to the first gear G1 is restricted. Specifically, a support surface (e.g., an annular surface) facing the second axial side L2 is formed on the inner peripheral surface of the cylindrical portion G1b. A stepped portion is formed on the inner peripheral surface of the cylindrical portion G1b, where the portion on the second axial side L2 has a larger diameter than the portion on the first axial side L1, and the support surface is formed on this stepped portion. In addition, a snap ring 78 (an example of a locking member) is locked on a portion of the inner peripheral surface of the cylindrical portion G1b closer to the second axial side L2 than the support surface. The outer ring raceway forming member 73a is arranged between the support surface on the inner surface of the cylindrical portion G1b and the snap ring 78 in the axial direction L so that movement toward the first axial side L1 is restricted by the support surface, and movement toward the second axial side L2 is restricted by the snap ring 78.

[0033] The inner race 74 includes a rolling element support portion 75 that supports the plurality of rolling elements 70, and a boss portion 76 that supports the rolling element support portion 75. An inner ring raceway surface is formed on the outer peripheral surface of the rolling element support portion 75. In this embodiment, a double-row (two-row) inner ring raceway surface is formed on the outer peripheral surface of the rolling element support portion 75. The boss portion 76 includes a cylindrical portion that is disposed radially inward (R1) relative to the rolling element support portion 75, and this cylindrical portion supports the rolling element support portion 75 from the radially inward (R1). The boss portion 76 (specifically, the cylindrical portion) is formed to extend toward the second axial side (L2) relative to the plurality of rolling elements 70. That is, the end portion of the boss portion 76 on the second axial side (L2) is disposed closer to the second axial side (L2) than the end portions of the plurality of rolling elements 70 (the plurality of second rolling elements 72 in this embodiment) on the second axial side (L2). In this embodiment, the boss portion 76 is further formed to extend toward the second axial side L2 relative to the first gear G1 (specifically, the cylindrical portion G1b). That is, the end of the boss portion 76 on the second axial side L2 is disposed closer to the second axial side L2 than the end of the first gear G1 on the second axial side L2.

[0034] In this embodiment, at least a portion of the rolling element support portion 75 and the boss portion 76 are integrally formed. Specifically, at least a portion of the rolling element support portion 75 and the boss portion 76 are integrally formed by the same member. In this embodiment, only a portion of the rolling element support portion 75 is integrally formed with the boss portion 76. Specifically, the portion of the rolling element support portion 75 that supports the plurality of second rolling elements 72 (i.e., the portion that forms the inner ring raceway surface on the axial second side L2) is integrally formed with the boss portion 76, while the portion of the rolling element support portion 75 that supports the plurality of first rolling elements 71 (i.e., the portion that forms the inner ring raceway surface on the axial first side L1) is a separate member from the boss portion 76. The portion of the rolling element support portion 75 that supports the plurality of first rolling elements 71 is formed by an inner ring raceway forming member 75a that is a separate member from the boss portion 76.

[0035] The inner ring raceway forming member 75a is attached to the outer peripheral surface of the boss portion 76 (specifically, the outer peripheral surface of the cylindrical portion) so that relative movement in both sides of the axial direction L with respect to the boss portion 76 is restricted. Specifically, a stepped surface 74a (e.g., an annular surface) facing the first axial side L1 is formed on the outer peripheral surface of the boss portion 76. A stepped portion is formed on the outer peripheral surface of the boss portion 76, where the portion on the first axial side L1 has a smaller diameter than the portion on the second axial side L2, and the stepped surface 74a is formed on this stepped portion. In addition, a crimped portion 74b is formed on the outer peripheral surface of the boss portion 76 in a portion closer to the first axial side L1 than the stepped surface 74a. The crimped portion 74b is formed by bending the end of the boss portion 76 on the first axial side L1 toward the radially outer side R2. The inner ring raceway forming member 75a is arranged in the axial direction L between the crimping portion 74b on the outer surface of the boss portion 76 and the step surface 74a so that movement toward the axial first side L1 is restricted by the crimping portion 74b, and movement toward the axial second side L2 is restricted by the step surface 74a.

[0036] As described above, the outer ring raceway forming member 73a of the outer race 73 is attached to the first gear G1 so as to restrict relative movement in both directions in the axial direction L with respect to the first gear G1. A portion of the rolling element support portion 75 of the inner race 74 is integrally formed with the boss portion 76 of the inner race 74, and the portion of the rolling element support portion 75 that is not integrally formed with the boss portion 76 is formed by the inner ring raceway forming member 75a. The inner ring raceway forming member 75a is attached to the boss portion 76 so as to restrict relative movement in both directions in the axial direction L with respect to the boss portion 76. Furthermore, relative movement in the axial direction L between the inner race 74 and the outer race 73 is restricted to a range corresponding to the gap formed therebetween. Therefore, the attachment structure between the first gear G1 and the target bearing 60 and the structure of the target bearing 60 restrict relative movement in the axial direction L between the inner race 74 and the first gear G1.

[0037] A boss portion 76 of the inner race 74 is fixed to the target wall portion 51 of the case 5. In this embodiment, the boss portion 76 has a flange-shaped portion 77. The flange-shaped portion 77 is formed to extend radially outwardly R2 from the first gear G1 on the axial second side L2. That is, an end portion of the flange-shaped portion 77 on the radially outer side R2 is disposed radially outwardly R2 from an end portion of the radially outer side R2 of the first gear G1. The flange-shaped portion 77 is fastened to the target wall portion 51 by a fastening member 80 such as a bolt while contacting the target wall portion 51 from the axial first side L1. The fastening member 80 is inserted through an insertion hole 77a formed in the flange-shaped portion 77 from the axial first side L1 and fastened to a fastening hole 52 formed in the target wall portion 51. Although not shown, the flange-shaped portion 77 is fastened and fixed to the target wall portion 51 by fastening members 80 at a plurality of positions in the circumferential direction (direction going around the first axis A1).

[0038] During manufacture of the vehicle drive transmission device 100, the target bearing 60 is attached to the target wall portion 51 of the case 5, and then the first gear G1 is attached to the target bearing 60. Specifically, the flange-shaped portion 77 of the boss portion 76 is fastened and fixed to the target wall portion 51 with the fastening member 80, thereby attaching the entire target bearing 60 (i.e., the outer race 73, the inner race 74, and the plurality of rolling elements 70) to the target wall portion 51. Then, with the preload applied to the rolling elements 70 adjusted by the crimping portion 74b, the first gear G1 is attached to the target bearing 60. Specifically, the first gear G1 is moved to the second axial side L2 relative to the target bearing 60 so that the inner circumferential surface of the cylindrical portion G1b of the first gear G1 fits (here, so as to fit by clearance fit) with the outer circumferential surface of the outer race 73, and then a snap ring 78 is locked onto the inner circumferential surface of the cylindrical portion G1b. In this way, the first gear G1 can be attached to the target bearing 60 with the preload of the target bearing 60 adjusted, which makes it easier to assemble the target bearing 60 and the first gear G1 to the case 5.

[0039] In this embodiment, the boss portion 76 and the target wall portion 51 are positioned by a knock pin 81. Note that, here, positioning refers to positioning within a plane perpendicular to the axial direction L. Specifically, the boss portion 76 and the target wall portion 51 are positioned by the knock pin 81, which is arranged to fit into a hole formed in the flange-shaped portion 77 of the boss portion 76 and a hole formed in the target wall portion 51. In the example shown in FIG. 2 , the hole formed in the flange-shaped portion 77 is formed coaxially with the insertion hole 77a, and the hole formed in the target wall portion 51 is formed coaxially with the fastening hole 52. The knock pin 81 is formed in a cylindrical shape. The flange-shaped portion 77 is fastened and fixed to the target wall portion 51 by a fastening member 80 arranged to penetrate the inner circumferential surface of the knock pin 81.

[0040] As described above, the inner race 74 of the target bearing 60 has a structure in which the rolling element support portion 75, which supports the multiple rolling elements 70, is supported by the boss portion 76 fixed to the target wall portion 51 of the case 5. The boss portion 76, which supports the rolling element support portion 75, is a separate member from the case 5. This makes it easier to use a material suitable for supporting the first gear G1 for the boss portion 76. Unlike this configuration, if a boss portion similar to the boss portion 76 were formed integrally with the case 5 using the same member, it could be difficult to ensure the strength and rigidity, especially if the diameter of the boss portion is small. In contrast, by making the boss portion 76 a separate member from the case 5, it is easier to ensure the strength and rigidity required for the support structure of the first gear G1, even if the diameter of the boss portion 76 is small.

[0041] For example, the case 5 may be made of aluminum or an aluminum alloy, and the inner race 74 may be made of iron or steel. In this case, the case 5 may be made of a material that easily satisfies requirements for the case 5, such as workability and weight reduction, while the inner race 74, including the boss portion 76, may be made of a material that easily ensures the strength and rigidity required for the support structure of the first gear G1. Since the inner race 74 includes the rolling element support portion 75 and the boss portion 76, if the inner race 74 is made of iron or steel, the rolling element support portion 75 and the boss portion 76 are also made of iron or steel. In this case, in this embodiment, a member in which a portion of the rolling element support portion 75 and the boss portion 76 are integrally formed, and an inner ring raceway forming member 75a that forms the remaining portion of the rolling element support portion 75 are both made of iron or steel. Note that the materials that make up these two members may be different types of materials (e.g., different types of steel).

[0042] As described above, in this embodiment, the power transmission mechanism 2 includes a sun gear SG. The sun gear SG is provided in the planetary gear mechanism 3 included in the power transmission mechanism 2. In this embodiment, the sun gear SG is disposed adjacent to the first gear G1 on the axial first side L1 with the thrust bearing 61 interposed therebetween. Specifically, the first gear G1 includes a radially extending portion G1c extending from the cylindrical portion G1b toward the radially inner side R1. The radially extending portion G1c is disposed on the axial first side L1 relative to the plurality of rolling elements 70, so as to extend from the cylindrical portion G1b toward the radially inner side R1. In this embodiment, the radially extending portion G1c is formed integrally with the cylindrical portion G1b. The thrust bearing 61 is disposed between the radially extending portion G1c and the sun gear SG in the axial direction L. The first gear G1 is connected to the carrier CR via the radially extending portion G1c. In this embodiment, the sun gear SG corresponds to the "third gear."

[0043] In this embodiment, the first gear G1 and the sun gear SG are helical gears. The helical directions of the first gear G1 and the sun gear SG are set so that, in a driving force transmission state in which a thrust load directed toward the axial second side L2 is generated on the sun gear SG, the direction of the thrust load generated on the first gear G1 by meshing with the second gear G2 is directed toward the axial first side L1. For example, the helical direction of the sun gear SG is set so that a state in which torque that drives the vehicle forward is transmitted from the driving source 1 to the wheels W (vehicle forward movement state) becomes a driving force transmission state in which a thrust load directed toward the axial second side L2 is generated on the sun gear SG.

[0044] In this embodiment, the thrust load generated in the first gear G1 and directed toward the first axial side L1 is received by the snap ring 78, thereby preventing a large thrust load directed toward the first axial side L1 from being input to the planetary gear mechanism 3 via the thrust bearing 61. Specifically, the first gear G1 can move in the axial direction L relative to the inner race 74 due to a gap present inside the target bearing 60 and a gap present in the attachment portion between the first gear G1 and the target bearing 60 (specifically, the outer race 73). However, the size of the gaps in each portion and the position of the snap ring 78 are set so that the gap in the axial direction L between the first gear G1 (specifically, the radially extending portion G1c) and the sun gear SG (the gap at the portion where the thrust bearing 61 is disposed) is not clogged even when the first gear G1 moves to the axial first side L1 to the inner race 74 to the maximum extent.

[0045] In this embodiment, the boss portion 76 is used not only to fix the inner race 74 to the target wall portion 51 but also to supply oil to the inside of the input member 30. In the example shown in FIG. 2, as will be described below, the boss portion 76 is used to supply oil to the inside of the input member 30.

[0046] The input member 30 includes a cylindrical portion 31 formed to open to the second axial side L2. Note that the cylindrical portion 31 may also be formed to open to the first axial side L1. The cylindrical portion 31 is disposed on the radially inner side R1 of the boss portion 76, at a position overlapping with the boss portion 76 as viewed in the radial direction. The cylindrical portion 31 is inserted from the first axial side L1 into a hole formed in the boss portion 76 along the first axis A1, and is rotatably supported by a bearing 62 (here, a needle bearing) relative to the boss portion 76. The cylindrical portion 31 is disposed so as not to protrude toward the second axial side L2 relative to the boss portion 76. That is, the end of the cylindrical portion 31 on the second axial side L2 is disposed closer to the first axial side L1 than the end of the boss portion 76 on the second axial side L2.

[0047] The boss portion 76 has a target oil passage 91, to which oil is supplied from the second axial side L2, on the second axial side L2 with respect to the cylindrical portion 31. In the illustrated example, a supply oil passage 90 is formed in the target wall portion 51, which supplies oil to the target oil passage 91 from the second axial side L2. The supply oil passage 90 supplies oil supplied from an oil pump (not shown) to the target oil passage 91. The oil supplied from the supply oil passage 90 to the target oil passage 91 is supplied to an internal oil passage 32, which is an oil passage inside the cylindrical portion 31, and then supplied to parts to be lubricated and parts to be cooled. In the illustrated example, the oil in the internal oil passage 32 is supplied to a thrust bearing 61 from a through hole formed in the cylindrical portion 31, and then supplied to a bearing that rotatably supports the pinion gears (PG1, PG2) with respect to the pinion shaft PS. Also, although not shown in the figure, the oil in the internal oil passage 32 is connected to a cooling oil passage of the rotating electric machine serving as the driving source 1, and is configured to cool the rotating electric machine using oil supplied from the target oil passage 91 to the internal oil passage 32.

[0048] A portion of the oil supplied from the oil supply passage 90 to the target oil passage 91 does not flow into the internal oil passage 32, but passes through the radially outer side R2 of the cylindrical portion 31 and is then supplied to the bearing 62, and is then supplied to the target bearing 60 (specifically, the plurality of rolling elements 70). In the illustrated example, the target oil passage 91 has a reduced diameter portion 91a that reduces in diameter toward the internal oil passage 32. The reduced diameter portion 91a is formed so that its diameter decreases toward the first axial side L1, so that at the reduced diameter portion 91a, the cross-sectional area of ​​the target oil passage 91 decreases toward the first axial side L1. Therefore, the flow rate of the oil flowing toward the first axial side L1 in the target oil passage 91 can be increased at the reduced diameter portion 91a, which makes it easier to ensure an appropriate amount of oil is supplied from the target oil passage 91 to the internal oil passage 32.

[0049] Second Embodiment A second embodiment of a vehicle drive transmission device will be described with reference to the drawing (FIG. 3). The following description will focus on differences from the first embodiment. Points that are not specifically mentioned are the same as those in the first embodiment, and the same reference numerals will be used to omit detailed descriptions.

[0050] In this embodiment, the outer ring raceway forming member 73a included in the outer race 73 of the target bearing 60 is not a common member for the two rows of outer ring raceway surfaces, but rather an outer ring raceway forming member 73a that forms the outer ring raceway surface on the first axial side L1 and an outer ring raceway forming member 73a that forms the outer ring raceway surface on the second axial side L2 are provided separately. Also, in this embodiment, the rolling element support portion 75 included in the inner race 74 of the target bearing 60 is not formed integrally with the boss portion 76, but rather an inner ring raceway forming member 75a that forms the inner ring raceway surface on the second axial side L2 is provided in addition to an inner ring raceway forming member 75a that forms the inner ring raceway surface on the first axial side L1. Then, two inner ring raceway forming members 75a are arranged side by side in the axial direction L between the crimped portion 74b and the stepped surface 74a on the outer peripheral surface of the boss portion 76.

[0051] Furthermore, in this embodiment, the boss portion 76 and the target wall portion 51 are not positioned by the knock pin 81, but are positioned by the inner circumferential surface 53 of the case 5. Specifically, the boss portion 76 and the target wall portion 51 are positioned by bringing the outer circumferential surface of the flange-shaped portion 77 into contact with the inner circumferential surface 53 of the peripheral wall portion 50 from the radially inner side R1.

[0052] Third Embodiment A third embodiment of a vehicle drive transmission device will be described with reference to the drawing (FIG. 4). The following description will focus on differences from the second embodiment. Points that are not specifically mentioned are the same as those in the second embodiment, and the same reference numerals will be used to omit detailed descriptions.

[0053] In this embodiment, the target bearing 60 is a roller bearing, and the rolling elements 70 are rollers (here, tapered rollers). Also, in this embodiment, the snap ring 78 is disposed between the two outer ring raceway forming members 73a in the axial direction L, rather than on the second axial side L2 of the two outer ring raceway forming members 73a. Also, in this embodiment, the preload applied to the rolling elements 70 is adjusted not by the crimping portion 74b, but by a nut 79 threaded onto the end of the boss portion 76 on the first axial side L1.

[0054] In the present embodiment, the sun gear SG is disposed adjacent to the boss portion 76 on the first axial side L1 with the thrust bearing 61 interposed therebetween. Therefore, the thrust bearing 61 is disposed between the boss portion 76 and the sun gear SG in the axial direction L. In the present embodiment, the radially extending portion G1c extending from the cylindrical portion G1b of the first gear G1 to the radially inner side R1 is a separate member from the cylindrical portion G1b and is connected to the cylindrical portion G1b so as to rotate integrally with the cylindrical portion G1b.

[0055] Other Embodiments (1) In the above-described embodiments, the flange-shaped portion 77 of the boss portion 76 is formed to extend radially outward R2 from the first gear G1. However, the present disclosure is not limited to such a configuration, and the flange-shaped portion 77 may be configured not to extend radially outward R2 from the first gear G1. In this case, the flange-shaped portion 77 is fixed to the target wall portion 51, for example, in a region overlapping with the first gear G1 in an axial view along the axial direction L. Alternatively, the boss portion 76 may be formed to extend toward the second axial side L2 relative to the plurality of rolling elements 70 but not to extend toward the second axial side L2 relative to the first gear G1, and the flange-shaped portion 77 may be fixed to the target wall portion 51 in a region radially inward R1 from the first gear G1 (specifically, the cylindrical portion G1b) and overlapping with the first gear G1 in a radial view.

[0056] (2) In the above embodiments, the boss portion 76 includes the flange-shaped portion 77. However, the present disclosure is not limited to such a configuration, and the boss portion 76 may not include the flange-shaped portion 77 if the boss portion 76 is fixed to the target wall portion 51 at a portion other than the flange-shaped portion 77.

[0057] (3) In each of the above embodiments, the first gear G1 and the sun gear SG are helical gears. However, the present disclosure is not limited to such a configuration, and the first gear G1 and the sun gear SG may be gears other than helical gears (for example, spur gears).

[0058] (4) In the above embodiments, the power transmission mechanism 2 includes the planetary gear mechanism 3 and the differential gear mechanism 4. However, the present disclosure is not limited to such a configuration, and the power transmission mechanism 2 may be configured to not include one or both of the planetary gear mechanism 3 and the differential gear mechanism 4.

[0059] (5) Note that the configurations disclosed in the above-described embodiments can be applied in combination with configurations disclosed in other embodiments (including combinations of embodiments described as other embodiments) as long as no contradictions arise. Regarding other configurations, the embodiments disclosed in this specification are merely examples in all respects. Therefore, various modifications can be made as appropriate within the scope of the present disclosure.

[0060] [Summary of this embodiment] The above-described embodiment of the vehicle drive transmission device will be summarized below.

[0061] The vehicle drive transmission device (100) includes an input member (30) drivingly connected to a drive source (1), an output member (20) drivingly connected to a wheel (W), a power transmission mechanism (2) that transmits driving force between the input member (30) and the output member (20), and a case (5) that houses the power transmission mechanism (2). The power transmission mechanism (2) includes a first gear (G1) and a second gear (G2) that meshes with the first gear (G1). a first gear (G2) in which a direction along a rotation axis (A1) of the first gear (G1) is defined as an axial direction (L), a direction perpendicular to the rotation axis (A1) is defined as a radial direction (R), one side of the axial direction (L) is defined as an axial first side (L1), and the other side of the axial direction (L) is defined as an axial second side (L2), and the first gear (G1) is disposed on the axial first side (L1) with respect to a target wall portion (51) of the case (5), and a target The target bearing (60) is rotatably supported relative to the case (5) by a bearing (60), and includes a plurality of rolling elements (70) arranged on the inner side (R1) of the radial direction (R) relative to a first gear tooth portion (G1a), which is a tooth portion of the first gear (G1), at a position overlapping with the first gear tooth portion (G1a) when viewed radially along the radial direction (R), and an inner race (74) supporting the plurality of rolling elements (70) from the inner side (R1) of the radial direction (R), and the inner race (74) includes a rolling element support portion (75) supporting the plurality of rolling elements (70), and a boss portion (76) formed to support the rolling element support portion (75) and extend toward the second axial side (L2) relative to the plurality of rolling elements (70), and the boss portion (76) is fixed to the target wall portion (51) of the case (5).

[0062] According to this configuration, the inner race 74 of the target bearing 60 is configured such that the rolling element support portion 75, which supports the rolling element 70, is supported by the boss portion 76 fixed to the target wall portion 51 of the case 5. This allows the first gear G1, which is subjected to a load in the radial direction R due to meshing with the second gear G2, to be appropriately supported by the case 5. Furthermore, according to this configuration, the boss portion 76, which supports the rolling element support portion 75, is a separate member from the case 5. Therefore, the boss portion 76 can be made of a material suitable for supporting the first gear G1. This makes it easy to ensure appropriate strength and rigidity in the support structure for the first gear G1.

[0063] As described above, according to this configuration, when the power transmission mechanism (2) of the vehicle drive transmission device (100) includes a first gear (G1) and a second gear (G2) that meshes with the first gear (G1), it becomes easier to properly support the first gear (G1).

[0064] Preferably, at least a portion of the rolling element support portion (75) and the boss portion (76) are integrally formed.

[0065] According to this configuration, the boss portion (76) that supports the rolling element support portion (75) is formed integrally with at least a portion of the rolling element support portion (75), which reduces the number of parts and makes it easier to reduce the size of the target bearing (60) in the radial direction (R).

[0066] Furthermore, it is preferable that the boss portion (76) has a flange-shaped portion (77) formed so as to extend further outward (R2) in the radial direction (R) than the first gear (G1) on the second axial side (L2) than the first gear (G1), and that the flange-shaped portion (77) is fastened and fixed to the target wall portion (51) of the case (5) by a fastening member (80) while contacting the target wall portion (51) from the first axial side (L1).

[0067] According to this configuration, the first gear (G1) and the target wall portion (51) can be disposed close to each other in the axial direction (L), and the boss portion (76) can be appropriately fixed to the target wall portion (51). Therefore, it is easy to reduce the size of the entire device in the axial direction (L).

[0068] Furthermore, it is preferable that the mounting structure of the first gear (G1) and the target bearing (60) and the structure of the target bearing (60) are configured to restrict relative movement between the inner race (74) and the first gear (G1) in the axial direction (L), and that the power transmission mechanism (2) further includes a third gear (SG) arranged adjacent to the first gear (G1) on the axial first side (L1) via a thrust bearing (61), and that the first gear (G1) and the third gear (SG) are helical gears, and that the helical directions of the first gear (G1) and the third gear (SG) are set so that, in a driving force transmission state in which a thrust load toward the axial second side (L2) is generated in the third gear (SG), the direction of the thrust load generated in the first gear (G1) by meshing with the second gear (G2) is toward the axial first side (L1).

[0069] In this configuration, relative movement between the inner race (74) and the first gear (G1) in the axial direction (L) is restricted, and the third gear (SG) is disposed adjacent to the first gear (G1) on the first axial side (L1) via the thrust bearing (61). When a thrust load toward the second axial side (L2) is generated on the third gear (SG), the load can act on the target bearing (60) via the thrust bearing (61) and the first gear (G1). According to this configuration, in a driving force transmission state in which a thrust load toward the second axial side (L2) is generated on the third gear (SG), the thrust load toward the first axial side (L1) can be applied from the first gear (G1) to the third gear (SG) via the thrust bearing (61). This reduces the load acting on the target bearing (60).

[0070] Preferably, the case (5) is made of aluminum or an aluminum alloy, and the inner race (74) is made of iron or steel.

[0071] According to this configuration, the material constituting the case (5) can be one that easily satisfies requirements for the case (5), such as workability and light weight, while the material constituting the inner race (74) can be one that easily ensures the strength and rigidity required for the support structure of the first gear (G1).

[0072] Furthermore, it is preferable that the driving source (1) is a rotating electric machine having a rotor (10) drivingly connected to the input member (30), the input member (30) has a cylindrical portion (31) formed to open to the second axial side (L2), the cylindrical portion (31) is arranged on the inner side (R1) of the radial direction (R) with respect to the boss portion (76) and at a position overlapping with the boss portion (76) as viewed in the radial direction, the boss portion (76) has a target oil passage (91) on the second axial side (L2) with respect to the cylindrical portion (31), to which oil is supplied from the second axial side (L2), and the target oil passage (91) has a reduced diameter portion (91a) whose diameter reduces toward the oil passage (32) inside the cylindrical portion (31).

[0073] According to this configuration, the flow rate of oil flowing toward the first axial side (L1) in the target oil passage (91) can be increased in the reduced diameter portion (91a). Therefore, the oil in the target oil passage (91) can be appropriately supplied to the oil passage (32) inside the cylindrical portion (31) that is disposed on the first axial side (L1) of the target oil passage (91). For example, when the oil passage (32) inside the cylindrical portion (31) is connected to a cooling oil passage of a rotating electrical machine serving as the driving source (1), the rotating electrical machine can be appropriately cooled by the oil supplied to the oil passage (32) inside the cylindrical portion (31) in this manner.

[0074] The drive source (1) is a rotating electric machine including a rotor (10) drivingly connected to the input member (30), and the output member (20) includes a first output member (21) drivingly connected to the first wheel (W1) and a second output member (22) drivingly connected to the second wheel (W2). The power transmission mechanism (2) is a planetary gear mechanism that reduces the rotation of the input member (30) and transmits it to the first gear (G1). and a differential gear mechanism (4) that distributes the rotation of the second gear (G2) to the first output member (21) and the second output member (22), and it is preferable that the input member (30) and the planetary gear mechanism (3) are arranged coaxially with the first gear (G1), and the first output member (21), the second output member (22), and the differential gear mechanism (4) are arranged coaxially with the second gear (G2).

[0075] According to this configuration, in a two-axis vehicle drive transmission device (100) in which each element is arranged along two axes (A1, A2), the support structure of the first gear (G1), to which the rotation of the input member (30) is reduced in speed by the planetary gear mechanism (3) and transmitted, can be made into a support structure that can easily ensure appropriate strength and rigidity.

[0076] It is sufficient for the vehicle drive transmission device according to the present disclosure to achieve at least one of the above-described effects. [Explanation of symbols]

[0077] 1: drive source, 2: power transmission mechanism, 5: case, 20: output member, 30: input member, 51: target wall portion, 60: target bearing, 61: thrust bearing, 70: rolling element, 74: inner race, 75: rolling element support portion, 76: boss portion, 77: flange-shaped portion, 80: fastening member, 100: vehicle drive transmission device, A1: first axis (rotation axis of first gear), G1: first gear, G1a: first gear tooth portion, G2: second gear, L: axial direction, L1: first axial side, L2: second axial side, R: radial direction, R1: radially inner side (radially inner side), R2: radially outer side (radially outer side), SG: sun gear (third gear), W: wheel, W1: first wheel, W2: second wheel

Claims

1. an input member drivingly connected to a drive source; an output member drivingly connected to the wheels; a power transmission mechanism that transmits a driving force between the input member and the output member; a case that houses the power transmission mechanism, the power transmission mechanism includes a first gear and a second gear that meshes with the first gear, A direction along the rotation axis of the first gear is defined as an axial direction, a direction perpendicular to the rotation axis is defined as a radial 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 first gear is disposed on a first axial side of a symmetric wall portion of the case and is rotatably supported with respect to the case by a symmetric bearing; the target bearing includes a plurality of rolling elements arranged radially inside a first gear tooth portion that is a tooth portion of the first gear and at a position overlapping with the first gear tooth portion as viewed in the radial direction; and an inner race that supports the plurality of rolling elements from the radially inside, the inner race includes a rolling element support portion that supports the plurality of rolling elements, and a boss portion that supports the rolling element support portion and is formed to extend toward the second axial side relative to the plurality of rolling elements, The boss portion is fixed to the target wall portion of the case.

2. 2. The vehicle drive transmission device according to claim 1, wherein at least a portion of the rolling element support portion and the boss portion are integrally formed.

3. the boss portion includes a flange-like portion formed on the second axial side relative to the first gear and extending radially outward relative to the first gear, The vehicle drive transmission device according to claim 1 or 2, wherein the flange-shaped portion is fastened and fixed by a fastening member in a state in which the flange-shaped portion is in contact with the target wall portion of the case from the first axial side.

4. an attachment structure between the first gear and the target bearing and a structure of the target bearing are configured to restrict relative movement between the inner race and the first gear in the axial direction, the power transmission mechanism further includes a third gear disposed adjacent to the first gear on the first axial side with a thrust bearing interposed therebetween, the first gear and the third gear are helical gears, 3. The vehicle drive transmission device according to claim 1, wherein the helical directions of the first gear and the third gear are set so that, in a driving force transmission state in which a thrust load directed toward the second axial side is generated on the third gear, a thrust load generated on the first gear by meshing with the second gear is directed toward the first axial side.

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