Vehicle drive systems

Abstract

To realize a vehicle drive system equipped with a compact disconnection mechanism that suppresses power loss when power transmission between the wheel's driving power source and the wheel is interrupted. [Solution] In the vehicle drive unit 1, the power transmission section 35 between the hollow transmission member 3 arranged coaxially with the rotor and the power transmission mechanism 5 is housed in the transmission mechanism housing chamber 95. Between the engagement member housing chamber 94, in which the friction engagement member 40 of the friction engagement device 4 is housed, and the transmission mechanism housing chamber 95, a restricting structure 8 is provided to restrict oil from entering the engagement member housing chamber 94. The restricting structure 8 comprises a partition 83 that separates the engagement member housing chamber 94 and the transmission mechanism housing chamber 95, a first sealing member 81 that seals the space between the input member 29 and the transmission member 3, and a second sealing member 82 that seals the space between the transmission member 3 and the partition 83.

Description

Technical Field

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

Background Art

[0002] Some vehicle drive devices including a driving force source for wheels and a power transmission mechanism for transmitting power between the driving force source and the wheels have a connection / disconnection mechanism capable of interrupting the power transmission between the driving force source and the wheels. A friction engagement device is often used as the connection / disconnection mechanism. The friction engagement device is known to be wet or dry. The wet type has advantages such as easy cooling compared to the dry type. However, during the interruption of power transmission, the rotational resistance due to the dragging of the oil present in the gap between the friction plates is likely to be relatively large. Therefore, in the case of a wet friction engagement device, as the rotational speed difference between the friction plates increases when the power transmission is interrupted, the dragging loss is likely to increase. Japanese Patent No. 5946285 discloses a vehicle drive device provided with a connection / disconnection mechanism on the wheel side, which is the side closest to the wheels in the power transmission path, i.e., on the axle that rotates at the same speed as the wheels. In this case, since the rotation is sufficiently decelerated by the reduction gear before being transmitted to the friction engagement device, even if the connection / disconnection mechanism is a wet friction engagement device, it is relatively easy to keep the dragging loss small, and the power loss of the vehicle drive device is also likely to be small.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when a connection / disconnection mechanism is provided on the wheel side in the power transmission path as described above, since the torque transmitted through the connection / disconnection mechanism is large, the friction engagement device is likely to be enlarged. As a result, the vehicle drive device is likely to be enlarged.

[0005] In light of the above background, there is a need for a vehicle drive system equipped with a compact disconnection mechanism that suppresses power loss when the power transmission between the wheel's driving force source and the wheel is interrupted. [Means for solving the problem]

[0006] A vehicle drive system in view of the above, comprising: a rotating electric machine; an input member arranged coaxially with the rotor of the rotating electric machine and rotating in conjunction with the rotor; a hollow transmission member arranged coaxially with the rotor; a friction engagement device provided in the power transmission path between the input member and the transmission member; an output member arranged on a separate axis from the rotor and driven to a wheel; a power transmission mechanism that transmits driving force between the transmission member and the output member; an engagement member housing chamber in which the friction engagement member of the friction engagement device is housed; and a case forming a transmission mechanism housing chamber in which the power transmission mechanism is housed, wherein the direction along the rotation axis of the rotor is defined as the axial direction, the direction perpendicular to the rotation axis is defined as the radial 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 engagement member housing chamber The device is positioned on the first axial side with respect to the rotor, the input member is inserted into the radially inner side of the transmission member, the power transmission section between the transmission member and the power transmission mechanism is positioned between the rotor and the engagement member housing chamber in the axial direction and is housed in the transmission mechanism housing chamber, a restricting structure is provided between the engagement member housing chamber and the transmission mechanism housing chamber to restrict oil in the transmission mechanism housing chamber from entering the engagement member housing chamber, the restricting structure comprises a partition portion which is a part that separates the engagement member housing chamber and the transmission mechanism housing chamber in the case, a first sealing member which seals the space between the input member and the transmission member on the first axial side with respect to the power transmission section, and a second sealing member which seals the space between the transmission member and the partition portion on the first axial side with respect to the power transmission section.

[0007] In this configuration, where the friction engagement device that connects and disconnects the power transmission path is arranged coaxially with the rotor, the friction engagement device is located closer to the rotor in the power transmission path from the rotor to the wheel. Therefore, compared to a configuration where the friction engagement device is located closer to the output member than in this configuration, it is easier to reduce the engagement torque of the friction engagement device. As a result, the friction engagement device can be miniaturized, and the vehicle drive system can be miniaturized. However, because the friction engagement device is located close to the rotor in the power transmission path, the difference in rotational speed of the friction engagement members when power transmission is interrupted tends to be large. Therefore, when the friction engagement members are in contact with oil, the drag between the friction engagement members tends to be large, and the power loss of the vehicle drive system tends to be large. However, in this configuration, the oil present in the transmission mechanism housing chamber to lubricate the power transmission mechanism is prevented from entering the engagement member housing chamber, thus reducing the drag of the friction engagement members. Thus, this configuration makes it possible to realize a vehicle drive system equipped with a compact disconnection mechanism that suppresses power loss when the power transmission between the wheel's driving power source and the wheel is interrupted.

[0008] Further features and advantages of the vehicle drive system will become clear from the following description of exemplary and non-limiting embodiments, which will be illustrated with reference to the drawings. [Brief explanation of the drawing]

[0009] [Figure 1] A skeleton diagram showing an example of a vehicle drive system. [Figure 2] Cross-sectional view of the first example of a vehicle drive system. [Figure 3] Enlarged cross-sectional view of the first example of a vehicle drive system. [Figure 4] Cross-sectional view of a second example of a vehicle drive system. [Figure 5] Enlarged cross-sectional view of the second example of a vehicle drive system. [Figure 6] Skeleton diagram showing other examples of vehicle drive systems [Figure 7] Cross-sectional view of a third example of a vehicle drive system. [Figure 8] Enlarged cross-sectional view of the third example of a vehicle drive system. [Modes for carrying out the invention]

[0010] Embodiments of the vehicle drive system will be described below with reference to the drawings. Figure 1 is a skeleton diagram of the vehicle drive system of the first and second examples, and Figures 2 to 5 are cross-sectional views of the vehicle drive system of the first and second examples. Figure 6 is a skeleton diagram of the vehicle drive system of the third example, and Figures 7 and 8 are cross-sectional views of the vehicle drive system of the third example. Hereinafter, individual explanations of matters common to the first, second, and third examples may be omitted.

[0011] As shown in Figures 1 to 8, the vehicle drive unit 1 comprises a rotating electric machine 2, an input member 29, a transmission member 3, a friction engagement device 4, an output member 77, a power transmission mechanism 5, and a case 9. In this specification, the direction along the first axis A1, which is the rotation axis of the rotor 21 of the rotating electric machine 2, is defined as the axial direction L, with one side of the axial direction L being the first axial side L1 and the other side being the second axial side L2. As will be described later, the vehicle drive unit 1 of this embodiment also includes a second axis A2 and a third axis A3 as separate axes parallel to the first axis A1. Therefore, the axial direction L is also the direction along the second axis A2 and the third axis A3. Furthermore, the direction perpendicular to each axis is defined as the radial direction R with respect to each axis, with the direction toward the axis being the radially inward R1 and the direction away from the axis being the radially outward R2.

[0012] The rotating electric machine 2 is a traction motor that serves as the driving force source for the vehicle's wheels W. The rotating electric machine 2 functions as an electric motor that drives the wheels W by receiving power from a DC power source (not shown), and also functions as a generator that generates electricity from the power from the wheels W and supplies power to the DC power source. The rotating electric machine 2 comprises a rotor 21 and a stator 22. An input member 29 is connected to the rotor shaft 20, which rotates integrally with the rotor 21, for example, by a spline coupling. In this embodiment, the input member 29 rotates integrally with the rotor 21 and the rotor shaft 20. However, if the input member 29 is arranged coaxially with the rotor 21, a transmission or the like may be provided between the rotor shaft 20 and the input member 29. In other words, the input member 29 only needs to be arranged coaxially with the rotor 21 of the rotating electric machine 2 and rotate in conjunction with the rotor 21.

[0013] In this embodiment, the transmission member 3 is also arranged on the first shaft A1. The transmission member 3 is a hollow member and is located radially outward R2 of the input member 29 and is arranged coaxially with the rotor 21. In other words, the input member 29 is inserted through radially inward R1 of the transmission member 3. In this embodiment, the transmission member 3 is illustrated as being formed by two members: a gear arrangement portion on which the input gear 31 (described later) is arranged, and a clutch arrangement portion on which the first friction engagement member 41 (described later) is arranged. These two members are connected, for example, by spline engagement to form an integrated unit.

[0014] The friction engagement device 4 is provided in the power transmission path between the input member 29 and the transmission member 3. The friction engagement device 4 comprises a friction engagement member 40 that disconnects and connects the power transmission between the input member 29 and the transmission member 3. The friction engagement member 40 comprises a first friction engagement member 41 that rotates integrally with the transmission member 3 and a second friction engagement member 42 that rotates integrally with the input member 29. The first friction engagement member 41 is supported by the clutch arrangement portion of the transmission member 3, and the second friction engagement member 42 is supported by the input member. The friction engagement device 4 engages the first friction engagement member 41 and the second friction engagement member 42 by pressing them from the first axial side L1 to the second axial side L2. Preferably, the engagement surface of the friction engagement member 40 is provided with a material (friction material) that has a higher viscosity than the lubricating oil of the power transmission mechanism 5. For example, a friction material can be used that exhibits frictional force through viscous resistance by applying a mixture of high-viscosity oil and powder to a sheet-like material such as paper.

[0015] The friction engagement device 4 is equipped with an electric clutch motor 49 as an actuator that generates a pressing force. In the first example of the vehicle drive system 1, the clutch motor 49 is located on a different axis from the first shaft A1, and a pressing force is applied to the first friction engagement member 41 and the second friction engagement member 42 located on the first shaft A1 via a reduction gear 48 that reduces the rotation of the clutch motor 49. In the second example of the vehicle drive system 1, the clutch motor 49 is located on the first shaft A1, and a pressing force is applied to the first friction engagement member 41 and the second friction engagement member 42 located coaxially with the clutch motor 49 without the need for a reduction gear. The friction engagement device 4 of the third example of the vehicle drive system 1 will be described later. Note that the mechanism for generating the pressing force is not limited to an electric actuator, but may also use hydraulics or the like.

[0016] The transmission member 3 is rotatably supported relative to the case 9 by the transmission bearing B3. Specifically, the gear arrangement portion of the transmission member 3 is rotatably supported by the transmission bearing B3. As described above, the transmission member 3 comprises a gear arrangement portion and a clutch arrangement portion. The transmission bearing B3 is not only rotatably supported by the transmission member 3, but is also arranged to support the axial load acting on the transmission member 3 due to the engagement pressure in the axial direction L by the friction engagement device 4. In the first and second examples, a pair of transmission bearings B3 are arranged at two locations spaced apart in the axial direction L of the cylindrical transmission member, supporting the transmission member 3 at two locations in the axial direction L. When distinguishing between the pair of transmission bearings B3, the transmission bearing B3 located on the first axial side L1 is referred to as the first transmission bearing B31, and the transmission bearing B3 located on the second axial side L2 is referred to as the second transmission bearing B32. The input gear 31, which includes the power transmission section 35 described later, is positioned in the axial direction L between the first transmission bearing B31 and the second transmission bearing B32.

[0017] As shown in Figure 3, in the first example of the vehicle drive system 1, a first contact portion 33 is formed on the transmission member 3, projecting radially outward R2 on the second axial side L2 of the transmission member 3, and on the first axial side L1 of the position of the second transmission bearing B32. When an axial load toward the second axial side L2 is applied to the transmission member 3 by the engagement pressure in the axial direction L by the friction engagement device 4, the first contact portion 33 comes into contact with the second transmission bearing B32 from the first axial side L1. Since the second transmission bearing B32 is in contact with the first support portion 91 of the case 9 on the second axial side L2, the axial load acting on the transmission member 3 is supported by the first support portion 91 via the first contact portion 33 and the second transmission bearing B32.

[0018] As shown in FIGS. 3 and 5, in common to the vehicle drive device 1 of the first example and the second example, on the first axial side L1 of the transmission member 3, which is the first axial side L1 from the arrangement position of the first transmission bearing B31, the transmission member 3 includes a second contact portion 34 protruding radially outward R2. In the present embodiment, a form in which the transmission member 3 is formed by two members is exemplified, and the two members are connected so as to be integrated, for example, by spline engagement. A portion protruding radially outward R2 at the spline engagement portion becomes the second contact portion 34. When an axial load acting in the second axial direction L2 is applied to the transmission member 3 by the engagement pressure in the axial direction L by the friction engagement device 4, the second contact portion 34 contacts the first transmission bearing B31 from the first axial side L1.

[0019] As shown in FIG. 5, in the vehicle drive device 1 of the second example, on the second axial side L2 from the arrangement position of the first transmission bearing B31, a second support portion 93 protruding radially inward R1 from the case 9 (the inner wall of the cylindrical partition portion 83 described later) is formed in the case 9. When an axial load acting in the second axial direction L2 is applied to the transmission member 3 by the engagement pressure in the axial direction L by the friction engagement device 4, the second contact portion 34 contacts the first transmission bearing B31 from the first axial side L1, and the first transmission bearing B31 contacts the second support portion 93 from the first axial side L1, whereby the axial load is supported. In the vehicle drive device 1 of the second example, the axial load due to the engagement pressure in the axial direction L by the friction engagement device 4 is supported at two positions in the axial direction L of the first support portion 91 and the second support portion 93 via the first contact portion 33 and the second contact portion 34 of the transmission member 3.

[0020] Of course, in the first example as well, it is possible to be configured to include the second support portion 93 as in the second example and support the axial load due to the engagement pressure in the axial direction L by the friction engagement device 4 at two positions in the axial direction L. Also, in the second example as well, it is possible to be configured to support the axial load only by the first support portion 91 via the first contact portion 33 as in the first example. Further, in both the first example and the second example, it may be configured to support the axial load only by the second support portion 93.

[0021] In the first to third examples, the vehicle drive unit 1 includes an output member 77 that is arranged on a second shaft A2, which is parallel to the first shaft A1 on which the rotor 21 is located and is a separate shaft from the first shaft A1, and is driven and connected to the wheel W. In this embodiment, the power transmission mechanism 5 that transmits power between the transmission member 3 and the output member 77 includes an output differential gear device 7 that distributes driving force to a pair of wheels W. That is, the vehicle drive unit 1 includes a pair of output members 77 that are driven and connected to each of the pair of wheels W. In this embodiment, an example is shown in which the output members 77 and the wheels W are connected so as to rotate integrally via a drive shaft 79 or a connecting shaft.

[0022] In this specification, a drive connection refers to a state in which two rotating elements are connected in a manner that enables the transmission of driving force. A drive connection includes a state in which the two rotating elements are connected so as to rotate as a whole, or a state in which the two rotating elements are connected in a manner that enables the transmission of driving force via one or more members (power transmission members). Such power 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. Furthermore, such power transmission members may also include engagement devices that selectively transmit rotation and driving force, such as friction engagement devices and meshing engagement devices.

[0023] In the vehicle drive system 1 of the first and second examples, the transmission member 3 is equipped with an input gear 31, and the power transmission mechanism 5 that transmits driving force between the transmission member 3 and the output member 77 is equipped with a counter gear mechanism 6 that functions as a reduction gear and an output differential gear device 7. The vehicle drive system 1 of the third example will be described later. The input gear 31 is a gear that is integrally formed with the transmission member 3 and rotates integrally with the transmission member 3. The counter gear mechanism 6 is arranged on a third shaft A3, which is a separate shaft from the first shaft A1 and the second shaft A2. The counter gear mechanism 6 is equipped with a large-diameter first counter gear 61 that meshes with the input gear 31 which rotates integrally with the transmission member 3, and a small-diameter second counter gear 62 which rotates integrally with the first counter gear 61 and has a smaller gear diameter than the first counter gear 61. The meshing portion between the input gear 31 and the first counter gear 61 is a power transmission portion 35 that transmits power between the transmission member 3 and the power transmission mechanism 5. The output differential gear device 7 includes a differential input gear 70 that meshes with the second counter gear 62, and a differential gear mechanism that distributes the driving force transmitted to the differential input gear 70 to a pair of output members 77.

[0024] Furthermore, the power transmission mechanism 5 may be equipped with a planetary gear mechanism as a reduction gear instead of the counter gear mechanism 6. Also, the power transmission mechanism 5 may be equipped with a multi-speed transmission instead of a fixed-speed transmission like the counter gear mechanism 6. In addition, the output differential gear device 7 may distribute the driving force transmitted to the differential input gear 70 at a constant speed, or it may distribute it after reducing the speed. That is, in the first and second examples, the power transmission mechanism 5 is equipped with a reduction gear to transmit the driving force between the transmission member 3 and the output member 77. Furthermore, the power transmission mechanism 5 is not limited to a mechanism that transmits power to a pair of wheels W with an output differential gear device 7, but may be a mechanism that transmits power to a single wheel W without an output differential gear device 7.

[0025] Here, it is preferable that the power transmission section 35 between the transmission member 3 and the power transmission mechanism 5 be the meshing section of a helical gear. The helical gear is preferably oriented such that, in the rotational direction of the power transmission section 35 when the vehicle is moving forward, the direction of the axial load acting on the transmission member 3 due to the meshing of the helical gear is opposite to the direction of the axial load acting on the transmission member 3 due to the engagement pressure of the friction engagement device 4. When an axial load toward the second axial side L2 is acted on the transmission member 3 due to the engagement pressure toward the axial direction L by the friction engagement device 4, at least a portion of the axial load can be offset in the power transmission section 35 by the axial load generated by the meshing of the helical gear in the power transmission section 35. As a result, as described above, the axial load supported by the transmission bearing B3 can be reduced via the first contact section 33 and the second contact section 34, thereby reducing the load on the transmission bearing B3.

[0026] In the first, second, and third examples, the differential gear mechanism of the output differential gear unit 7 is a planetary gear mechanism. The planetary gear mechanism comprises a ring gear 71, a sun gear 72, a plurality of first pinion gears 74 that mesh with the ring gear 71, a plurality of second pinion gears 75 that mesh with the first pinion gears 74 and the sun gear 72, and a carrier 73 that rotatably supports the first pinion gears 74 and the second pinion gears 75. In this embodiment, the differential input gear 70, which is an external gear, and the ring gear 71, which is an internal gear, are made of the same component and rotate integrally. The sun gear 72 and the carrier 73 each correspond to a pair of output members 77. Here, an example is given in which the differential gear mechanism of the output differential gear unit 7 is a planetary gear mechanism, but the differential gear mechanism may also be a bevel gear mechanism. Since differential gear mechanisms using bevel gears are well-known, a detailed explanation will be omitted.

[0027] When power is transmitted between the input member 29 and the transmission member 3 via the friction engagement device 4, power is transmitted in the following order: rotor 21, rotor shaft 20, input member 29, transmission member 3, input gear 31, first counter gear 61, second counter gear 62, differential input gear 70, ring gear 71, first pinion gear 74, second pinion gear 75, and a pair of output members 77 (sun gear 72, carrier 73). When the transmission of power between the input member 29 and the transmission member 3 is interrupted by the friction engagement device 4, the driving force from the rotor 21 is not transmitted to the output members 77.

[0028] In this embodiment, the friction engagement device 4, which connects and disconnects the power transmission path, is arranged coaxially with the rotor 21, and the friction engagement device 4 is positioned on the side closer to the rotor 21 in the power transmission path from the rotor 21 to the wheel W. Therefore, the engagement torque of the friction engagement device 4 is smaller compared to a configuration in which the friction engagement device 4 is positioned closer to the output member 77 than in this embodiment. As a result, the friction engagement device 4 is easier to miniaturize, and the vehicle drive unit 1 is easier to miniaturize.

[0029] Case 9 forms at least an engagement member housing chamber 94 in which the friction engagement member 40 of the friction engagement device 4 is housed, and a transmission mechanism housing chamber 95 in which the power transmission mechanism 5 is housed. The engagement member housing chamber 94 and the transmission mechanism housing chamber 95 are separated by a partition 83, which is a wall member formed integrally with case 9 or formed by a separate member. In this embodiment, at least a portion of the input member 29 and the transmission member 3 are also arranged in the transmission mechanism housing chamber 95. The transmission mechanism housing chamber 95 and the engagement member housing chamber 94 are arranged in the order of transmission mechanism housing chamber 95 and engagement member housing chamber 94 from the axial second side L2 toward the axial first side L1. At least a portion of the axial position of the transmission mechanism housing chamber 95 and the engagement member housing chamber 94 may overlap. The power transmission unit 35 that transmits power between the transmission member 3 and the power transmission mechanism 5 is located between the rotor 21 and the engagement member housing chamber 94 in the axial direction L and is housed in the transmission mechanism housing chamber 95.

[0030] As shown in Figures 2 to 8, in the first, second, and third examples, the case 9 of the vehicle drive unit 1 of this embodiment further includes a rotating electric machine housing chamber 92 in which the rotating electric machine 2 is housed. However, the case 9 may not include the rotating electric machine housing chamber 92, and the rotating electric machine 2 may be housed in a separate case and driven-connected to an input member 29 housed in a transmission mechanism housing chamber 95. When the case 9 includes the rotating electric machine housing chamber 92, the rotating electric machine housing chamber 92, the transmission mechanism housing chamber 95, and the engaging member housing chamber 94 are arranged in that order from the second axial side L2 to the first axial side L1. The rotating electric machine housing chamber 92 and the transmission mechanism housing chamber 95 may overlap in at least a portion of their axial position L, and the transmission mechanism housing chamber 95 and the engaging member housing chamber 94 may overlap in at least a portion of their axial position L.

[0031] The stator coil 23 of the rotating electric machine 2 generates heat due to the large current flowing through it. For this reason, the stator coil 23 is often cooled by oil. Also, the bearings that rotatably support the rotor shaft 20 generate heat due to friction. To reduce friction and cool the frictional heat, the bearings are lubricated with oil. Consequently, oil is scattered inside the rotating electric machine housing chamber 92. In addition, the bearings that rotatably support the input member 29 and the transmission member 3, the bearings that rotatably support the counter gear mechanism 6 and the output differential gear device 7, and the gear meshing parts are also lubricated with oil to reduce friction and cool the frictional heat. Consequently, oil is also scattered inside the transmission mechanism housing chamber 95. When the friction engagement members 40 come into contact with oil, the viscosity of the oil tends to increase the drag between the friction engagement members 40 (in this case, the drag between the first friction engagement member 41 and the second friction engagement member 42), which tends to increase the power loss in the vehicle drive unit 1 when power transmission between the rotor 21 and the output member 77 is interrupted.

[0032] As described above, in the power transmission path from the rotor 21 to the wheel W, the configuration of this embodiment makes it easier to reduce the engagement torque of the friction engagement device 4 compared to a configuration in which the friction engagement device 4 is positioned closer to the output member 77 than in the configuration of this embodiment. However, because the friction engagement device 4 is positioned closer to the rotor 21 in the power transmission path, the difference in rotational speed between the first friction engagement member 41 and the second friction engagement member 42 when power transmission is interrupted tends to be large. For this reason, when the friction engagement member 40 is in contact with oil, the drag between the friction engagement members 40 tends to increase, and the power loss of the vehicle drive unit 1 tends to increase.

[0033] In this embodiment, the friction engagement member 40 is housed in the engagement member housing chamber 94, and no oil is supplied to the engagement member housing chamber 94. However, if oil from the transmission mechanism housing chamber 95 or the like enters the engagement member housing chamber 94, there is a risk that the friction engagement member 40 will come into contact with the oil. For this reason, a restricting structure 8 is provided between the engagement member housing chamber 94 and the transmission mechanism housing chamber 95 to restrict the oil in the transmission mechanism housing chamber 95 from entering the engagement member housing chamber 94. The power transmission section 35 between the transmission member 3 and the power transmission mechanism 5 is a gear meshing section and requires lubrication with oil. Therefore, the power transmission section 35 is located between the rotor 21 and the engagement member housing chamber 94 in the axial direction L and is housed in the transmission mechanism housing chamber 95.

[0034] The restricting structure 8 comprises a compartment 83 and a sealing member 80. The sealing member 80 comprises a first sealing member 81 and a second sealing member 82. The compartment 83 is part of the case 9 and is the part that separates the engagement member housing chamber 94 and the transmission mechanism housing chamber 95 in the case 9. The first sealing member 81 seals the space between the input member 29 and the transmission member 3 on the first axial side L1 relative to the power transmission section 35. The second sealing member 82 seals the space between the transmission member 3 and the compartment 83 on the first axial side L1 relative to the power transmission section 35. In other words, because the oil present in the transmission mechanism housing chamber 95 for lubricating the power transmission mechanism 5 is prevented from entering the engagement member housing chamber 94, the drag of the friction engagement member 40 can be reduced.

[0035] In this embodiment, the first sealing member 81 is positioned between the radial R between the outer circumferential surface of the input member 29 and the inner circumferential surface of the transmission member 3. The second sealing member 82 is positioned between the radial R between the outer circumferential surface of the transmission member 3 and the partition portion 83. Specifically, the second sealing member 82 is positioned between the radial R between the outer circumferential surface of the transmission member 3 and the inner circumferential surface of the cylindrically formed partition portion 83. That is, here we illustrate a configuration in which the sealing members 80 (first sealing member 81 and second sealing member 82) are positioned to seal the gap in the radial direction R between the engaging member housing chamber 94 and the transmission mechanism housing chamber 95. However, the sealing members 80 may also be positioned to seal the gap in the axial direction L between the engaging member housing chamber 94 and the transmission mechanism housing chamber 95.

[0036] Furthermore, in the first and second examples of the vehicle drive unit 1 equipped with the counter gear mechanism 6, as shown in Figures 2 to 5, the axial L arrangement area of ​​the engaging member housing chamber 94 and the axial L arrangement area of ​​the second counter gear 62 overlap. Also, the engaging member housing chamber 94 and the first counter gear 61 overlap in an axial view along the axial L. That is, the engaging member housing chamber 94 is located radially outward R2 of the small-diameter second counter gear 62, and the engaging member housing chamber 94 is located at a different position in the axial L without overlapping radially R with respect to the large-diameter first counter gear 61, making it easier to miniaturize the case 9 and the vehicle drive unit 1.

[0037] The following describes the vehicle drive unit 1 of the third example. Explanations of configurations similar to those in the first and second examples will be omitted as appropriate. As shown in Figures 6 to 8, the vehicle drive unit 1 of the third example also comprises a rotating electric machine 2, an input member 29, a transmission member 3, a friction engagement device 4, a power transmission mechanism 5, and a case 9.

[0038] The input member 29 is arranged coaxially with the rotor 21 and rotates in conjunction with the rotor 21. The transmission member 3 is a hollow member arranged coaxially with the rotor 21. In the third example of the vehicle drive system 1, the transmission member 3 corresponds to a member that rotates integrally with the ring gear RG of the planetary gear mechanism that constitutes the transmission 50 described later (first transmission member 3A) and a member that rotates integrally with the carrier CA (second transmission member 3B). The friction engagement device 4 is provided in the power transmission path between the input member 29 and the transmission member 3. In this embodiment, the friction engagement device 4 disconnects and connects the power transmission between the input member 29 and the transmission member 3, and also causes the transmission 50 to selectively form multiple gear stages. The output member 77 is arranged on a separate shaft (second shaft A2) from the rotor 21 and is driven and connected to the wheel W. Similar to the first and second examples, in the third example of the vehicle drive unit 1, the output member 77 is the sun gear 72 and carrier 73 of an output differential gear unit configured by a planetary gear mechanism. In the first and second examples, the power transmission mechanism 5 comprised a counter gear mechanism 6 and an output differential gear unit 7, but in the third example of the vehicle drive unit 1, the power transmission mechanism 5 comprises an idler gear 67 located on the third shaft A3 and an output differential gear unit 7 located on the second shaft A2. As described above, in the third example as well, the case 9 also forms at least an engagement member housing chamber 94 in which the friction engagement member 40 of the friction engagement device 4 is housed, and a transmission mechanism housing chamber 95 in which the power transmission mechanism 5 is housed. In the third example as well, the engagement member housing chamber 94 is located on the axial first side L1 with respect to the rotor 21. Also, as described above, in the third example as well, the case 9 further comprises a rotating electric machine housing chamber 92.

[0039] In the third example of the vehicle drive system 1, a transmission 50 is provided between the input member 29 and the transmission member 3. The transmission 50 can form a first gear that reduces the rotation of the input member 29 and transmits it to the transmission member 3, a second gear that transmits the rotation of the input member 29 to the transmission member 3 at the same speed, and a neutral gear that does not transmit the rotation of the input member 29 to the transmission member 3. The friction engagement device 4 selectively realizes the first gear, second gear, and neutral gear of the transmission 50. When the friction engagement device 4 causes the transmission 50 to form a neutral gear, power transmission between the input member 29 and the transmission member 3 is interrupted. When the friction engagement device 4 causes the transmission 50 to form the first gear or the second gear, power is transmitted between the input member 29 and the transmission member 3.

[0040] In the third example, the transmission member 3 comprises a first transmission member 3A, which is a first portion located on the first axial side L1 relative to the transmission 50, and a second transmission member 3B, which is a second portion located on the second axial side L2 relative to the transmission 50. In both the first transmission member 3A and the second transmission member 3B, the input member 29 is inserted through the radially inner R1 of the first transmission member 3A and the second transmission member 3B. The first transmission member 3A is an input-side transmission member located between the input member 29 and the transmission 50 in the power transmission path. The second transmission member 3B is an output-side transmission member located between the transmission 50 and the power transmission mechanism 5 (in this case, the idler gear 67) in the power transmission path. An input gear 31 is integrally formed with the second transmission member 3B, and the second transmission member 3B and the input gear 31 rotate together. The input gear 31 may be made of a separate component from the second transmission member 3B and connected to the second transmission member 3B.

[0041] The transmission 50 is equipped with a planetary gear mechanism. The planetary gear mechanism comprises a ring gear RG, a sun gear SG, a plurality of pinion gears PG that mesh with the ring gear RG and the sun gear SG, and a carrier CA that rotatably supports the plurality of pinion gears PG. The sun gear SG is integrally formed with the input member 29, or is formed from a separate component from the input member 29 and connected to the input member 29, and rotates integrally with the input member 29. The ring gear RG is connected to the first transmission member 3A so as to rotate integrally with the first transmission member 3A. The carrier CA is connected to the second transmission member 3B so as to rotate integrally with the second transmission member 3B.

[0042] In the third example, the friction engagement device 4 comprises a first friction engagement member 41, a second friction engagement member 42, and a third friction engagement member 43 as friction engagement members 40. The first friction engagement member 41 also comprises a first friction engagement member 411 and a second friction engagement member 412. The first friction engagement member 41 rotates integrally with the transmission member 3 (here, the first transmission member 3A), as in the first and second examples. As described above, the first transmission member 3A rotates integrally with the ring gear RG of the transmission 50. That is, the first friction engagement member 411 and the second friction engagement member 412 both rotate integrally with the first transmission member 3A (ring gear RG). The second friction engagement member 42 rotates integrally with the input member 29, as in the first and second examples. As described above, the input member 29 rotates integrally with the sun gear SG of the transmission 50, so the second friction engagement member 42 rotates integrally with the sun gear SG. The third friction engagement member 43 is fixed to the case 9, which is a non-rotating member.

[0043] The friction engagement device 4 selectively realizes three states: a first state in which the first friction engagement member 411 and the second friction engagement member 42 are engaged, and the second friction engagement member 412 and the third friction engagement member 43 are not engaged; a second state in which the first friction engagement member 411 and the second friction engagement member 42 are not engaged, and the second friction engagement member 412 and the third friction engagement member 43 are engaged; and a third state in which the first friction engagement member 411 and the second friction engagement member 42 are not engaged, and neither the second friction engagement member 412 nor the third friction engagement member 43 are engaged. The first, second, and third states are realized by the pressing force generated by the clutch motor 49 provided in the friction engagement device 4. The action of the pressing force can be easily understood from the above explanation in the first example, so a detailed explanation is omitted. In the third example as well, the clutch motor 49 may be arranged on the first shaft A1, similar to the second example.

[0044] In the first state, the first friction engagement member 411 and the second friction engagement member 42 engage with each other, thereby connecting the sun gear SG and the ring gear RG of the transmission 50. As a result, the sun gear SG, the ring gear RG, and the carrier CA rotate together at a constant speed. The transmission 50 has a second gear stage that transmits the rotation of the input member 29 to the transmission member 3 at the same speed.

[0045] In the second state, the second first friction engagement member 412 and the third friction engagement member 43 engage, connecting the ring gear RG of the transmission 50 to the case 9, which is a non-rotating member. As a result, the rotation of the sun gear SG is reduced and output from the carrier CA. The transmission 50 has a first gear stage that reduces the rotation of the input member 29 and transmits it to the transmission member 3.

[0046] In the third state, the first friction engagement member 411 and the second friction engagement member 42 do not engage, nor do the second first friction engagement member 412 and the third friction engagement member 43 engage. The pinion gear PG rotates freely between the sun gear SG and the ring gear RG, and the carrier CA does not rotate. The transmission 50 has a neutral stage in which the rotation of the input member 29 is not transmitted to the transmission member 3.

[0047] In the third example as well, the power transmission section 35 between the transmission member 3 and the power transmission mechanism 5 is located between the rotor 21 and the engagement member housing chamber 94 in the axial direction L. In the vehicle drive system 1 of the third example, the power transmission section 35 corresponds to the part that transmits power between the second transmission member 3B and the power transmission mechanism 5, or the part that transmits power between the first transmission member 3A and the power transmission mechanism 5. If we consider the power transmission section 35 to transmit power between the second transmission member 3B and the power transmission mechanism 5, then the meshing portion between the input gear 31, which rotates integrally with the second transmission member 3B, and the idler gear 67 corresponds to the power transmission section 35. The meshing portion between the input gear 31 and the idler gear 67 is preferably the meshing portion of an inclined gear. If we consider the power transmission section 35 to transmit power between the first transmission member 3A and the power transmission mechanism 5, then the meshing portion between the ring gear RG, which rotates integrally with the first transmission member 3A, and the pinion gear PG corresponds to the power transmission section 35. Preferably, the meshing portion between the ring gear RG and the pinion gear PG is the meshing portion of an inclined gear. In this case, a part of the transmission 50 (e.g., the carrier CA) and the input gear 31 are also included in the power transmission mechanism 5.

[0048] When power is transmitted between the input member 29 and the transmission member 3 (in this case, the second transmission member 3B) via the friction engagement device 4, power is transmitted in the following order: rotor 21, rotor shaft 20, input member 29, transmission member 3, input gear 31, idler gear 67, differential input gear 70, ring gear 71, first pinion gear 74, second pinion gear 75, and a pair of output members 77 (sun gear 72, carrier 73). When the transmission of power between the input member 29 and the transmission member 3 is interrupted by the friction engagement device 4, the driving force from the rotor 21 is not transmitted to the output members 77.

[0049] As shown in Figures 6 and 7, the diameter of the idler gear 67 that meshes with the input gear 31 is larger than the diameter of the input gear 31. Also, the diameter of the differential input gear 70 that meshes with the idler gear 67 is larger than the diameter of the idler gear 67. Therefore, it can be said that a reduction gear is also configured in the power transmission path from the input gear 31 to the differential input gear 70.

[0050] Even when the transmission 50 forms a second gear stage that transmits the rotation of the input member 29 to the transmission member 3 (second transmission member 3B) at the same speed, the power transmission path between the transmission member 3 (second transmission member 3B) and the output member 77 can be said to include a reduction gear consisting of the input gear 31, idler gear 67, and differential input gear 70. Naturally, even when the transmission 50 forms a first gear stage that reduces the rotation of the input member 29 and transmits it to the transmission member 3 (second transmission member 3B), the power transmission path between the transmission member 3 (second transmission member 3B) and the output member 77 can also include a reduction gear consisting of the input gear 31, idler gear 67, and differential input gear 70. In this case, the power transmission path between the transmission member 3 (first transmission member 3A) and the output member 77 can be said to include a reduction gear by the transmission 50, as well as a reduction gear by the input gear 31, idler gear 67, and differential input gear 70. Furthermore, as described above, the output differential gear unit 7 may distribute the driving force transmitted to the differential input gear 70 at a constant speed, or it may distribute it at a reduced speed.

[0051] Thus, in the vehicle drive system 1 of the third example, the power transmission mechanism 5 is equipped with a reduction gear and transmits driving force between the transmission member 3 and the output member 77. Furthermore, as with the first and second examples, the power transmission mechanism 5 is not limited to a mechanism that transmits power to a pair of wheels W using an output differential gear 7, but may also be a mechanism that transmits power to a single wheel W without an output differential gear 7.

[0052] In the third example of the vehicle drive system 1, the friction engagement device 4 that connects and disconnects the power transmission path is arranged coaxially with the rotor 21, and the friction engagement device 4 is located on the side closer to the rotor 21 in the power transmission path from the rotor 21 to the wheel W. Therefore, the engagement torque of the friction engagement device 4 is smaller compared to the configuration in the third example of the vehicle drive system 1 where the friction engagement device 4 is located closer to the output member 77. As a result, the friction engagement device 4 is easier to miniaturize, and the vehicle drive system 1 is easier to miniaturize.

[0053] As shown in Figure 8, the first transmission member 3A is rotatably supported in the case 9 by the transmission bearing B3. Also, similar to the vehicle drive systems 1 of the first and second examples, the vehicle drive system 1 of the third example also has a contact portion (second contact portion 34) that protrudes radially outward R2 on the first axial side L1 of the first transmission member 3A, which is on the first axial side L1 of the transmission bearing B3. When an axial load toward the second axial side L2 is applied to the first transmission member 3A by the engagement pressure toward the axial side L by the friction engagement device 4, the second contact portion 34 comes into contact with the transmission bearing B3 from the first axial side L1.

[0054] Furthermore, as shown in Figure 8, a support portion (second support portion 93) is formed on the case 9 at the second axial side L2 from the position of the transmission bearing B3, projecting radially inward R1 from the case 9. When an axial load toward the second axial side L2 is applied to the first transmission member 3A by the engagement pressure in the axial direction L by the friction engagement device 4, the second contact portion 34 contacts the transmission bearing B3 from the first axial side L1, and the transmission bearing B3 contacts the second support portion 93 from the first axial side L1, thereby supporting the axial load.

[0055] As described above, in a configuration where the friction engagement device 4 is located upstream of the power transmission path from the rotor 21 to the wheel W, it is easy to reduce the engagement torque of the friction engagement device 4. However, when power transmission is interrupted, the rotational speed difference between the first friction engagement member 41 and the second friction engagement member 42, and the rotational speed difference between the first friction engagement member 41 and the third friction engagement member 43 tend to be large. For this reason, when the friction engagement members 40 are in contact with oil, the drag between the friction engagement members 40 tends to increase, and the power loss of the vehicle drive system 1 tends to increase.

[0056] In the third example of the vehicle drive system 1, the friction engagement member 40 is housed in the engagement member housing chamber 94, and no oil is supplied to the engagement member housing chamber 94. However, if oil from the transmission mechanism housing chamber 95 or the like enters the engagement member housing chamber 94, there is a risk that the oil will come into contact with the friction engagement member 40. For this reason, a restricting structure 8 is provided between the engagement member housing chamber 94 and the transmission mechanism housing chamber 95 to restrict the oil in the transmission mechanism housing chamber 95 from entering the engagement member housing chamber 94. The power transmission section 35 between the transmission member 3 and the power transmission mechanism 5 is a gear meshing section and requires lubrication by oil. Therefore, in the third example as well, the power transmission section 35 is located between the rotor 21 and the engagement member housing chamber 94 in the axial direction L and is housed in the transmission mechanism housing chamber 95.

[0057] The restricting structure 8 comprises a compartment 83 and a sealing member 80. The sealing member 80 comprises a first sealing member 81 and a second sealing member 82. The compartment 83 is part of the case 9 and is the part that separates the engagement member housing chamber 94 and the transmission mechanism housing chamber 95 in the case 9. The first sealing member 81 seals the space between the input member 29 and the transmission member 3 on the first axial side L1 relative to the power transmission section 35. The second sealing member 82 seals the space between the transmission member 3 and the compartment 83 on the first axial side L1 relative to the power transmission section 35. In other words, because the oil present in the transmission mechanism housing chamber 95 for lubricating the power transmission mechanism 5 is prevented from entering the engagement member housing chamber 94, the drag of the friction engagement member 40 can be reduced.

[0058] Furthermore, in the third example of the vehicle drive unit 1, as shown in Figures 7 and 8, the engagement member housing chamber 94 and the idler gear 67 (the gear that meshes with the input gear 31) overlap in an axial view along the axial direction L. That is, the engagement member housing chamber 94 is located at a different position in the axial direction L without overlapping radially R with respect to the gear that meshes with the input gear 31 (in this case, the idler gear 67), making it easier to miniaturize the case 9 and the vehicle drive unit 1.

[0059] The vehicle drive system (1) described above will be briefly summarized below.

[0060] In one embodiment, the vehicle drive system (1) includes a rotating electric machine (2), an input member (29) arranged coaxially (A1) with the rotor (21) of the rotating electric machine (2) and rotating in conjunction with the rotor (21), a hollow transmission member (3) arranged coaxially (A1) with the rotor (21), a friction engagement device (4) provided in the power transmission path between the input member (29) and the transmission member (3), an output member (77) arranged on a separate shaft (A2) from the rotor (21) and driven to a wheel (W), and a drive between the transmission member (3) and the output member (77). A vehicle drive device (1) comprising a power transmission mechanism (5) for transmitting power, an engagement member housing chamber (94) for housing a friction engagement member (40) of the friction engagement device (4), and a case (9) forming a transmission mechanism housing chamber (95) for housing the power transmission mechanism (5), wherein the direction along the rotation axis (A1) of the rotor (21) is defined as the axial direction (L), the direction perpendicular to the rotation axis (A1) is defined as the radial direction (R), one side of the axial direction (L) is defined as the axial first side (L1), and the other side of the axial direction (L) is defined as the axial second side (L2), and the engagement member housing The chamber (94) is positioned on the first axial side (L1) relative to the rotor (21), the input member (29) is inserted into the radially (R) inner side (R1) of the transmission member (3), the power transmission section (35) between the transmission member (3) and the power transmission mechanism (5) is positioned between the rotor (21) and the engagement member housing chamber (94) in the axial direction (L) and is housed in the transmission mechanism housing chamber (95), and between the engagement member housing chamber (94) and the transmission mechanism housing chamber (95), the oil in the transmission mechanism housing chamber (95) is supplied to the engagement member housing chamber (94) A restricting structure (8) is provided to prevent intrusion into the ) side, and the restricting structure (8) comprises a partition (83) which is a part that separates the engagement member housing chamber (94) and the transmission mechanism housing chamber (95) in the case (9), a first sealing member (81) which seals the space between the input member (29) and the transmission member (3) on the first axial side (L1) with respect to the power transmission section (35), and a second sealing member (82) which seals the space between the transmission member (3) and the partition (83) on the first axial side (L1) with respect to the power transmission section (35).

[0061] In this configuration, the friction engagement device (4) that connects and disconnects the power transmission path is arranged coaxially with the rotor (21). Because the friction engagement device (4) is located closer to the rotor (21) in the power transmission path from the rotor (21) to the wheel (W), it is easier to reduce the engagement torque of the friction engagement device (4) compared to a configuration in which the friction engagement device (4) is located closer to the output member (77) in the power transmission path from the rotor (21) to the wheel (W). Therefore, it is easier to miniaturize the friction engagement device (4) and thus easier to miniaturize the vehicle drive unit (1). However, because the friction engagement device (4) is located close to the rotor (21) in the power transmission path, the difference in rotational speed of the friction engagement member (40) when power transmission is interrupted tends to be large. Therefore, when the friction engagement member (40) is in contact with oil, the drag between the friction engagement members (40) tends to be large, and the power loss of the vehicle drive unit (1) tends to be large. However, with this configuration, the oil present in the transmission mechanism housing chamber (95) for lubricating the power transmission mechanism (5) is prevented from entering the engagement member housing chamber (94), thus reducing the drag of the friction engagement member (40). In this way, with this configuration, it is possible to realize a vehicle drive system (1) equipped with a compact disconnection mechanism while suppressing power loss when the power transmission between the driving force source of the wheel (W) and the wheel (W) is interrupted.

[0062] Furthermore, the vehicle drive unit (1) preferably includes a power transmission mechanism (5) comprising a counter gear mechanism (6) having a large-diameter first counter gear (61) that meshes with a gear (31) that rotates integrally with the transmission member (3), and a small-diameter second counter gear (62) that rotates integrally with the first counter gear (61), wherein the axial (L) arrangement region of the engagement member housing chamber (94) and the axial (L) arrangement region of the second counter gear (62) overlap, and the engagement member housing chamber (94) and the first counter gear (61) overlap in an axial view along the axial direction (L).

[0063] With this configuration, the engagement member housing chamber (94) is located on the radially (R) outer side (R2) of the small-diameter second counter gear (62), and the engagement member housing chamber (94) is located at a different position in the axial direction (L) without overlapping in the radial direction (R) with respect to the large-diameter first counter gear (61), making it easier to miniaturize the vehicle drive unit (1).

[0064] Furthermore, the vehicle drive unit (1) preferably comprises a friction engagement member (40) which includes a first friction engagement member (41) that rotates integrally with the transmission member (3) and a second friction engagement member (42) that rotates integrally with the input member (29), and the friction engagement device (4) engages the first friction engagement member (41) and the second friction engagement member (42) by pressing them from the first axial side (L1) to the second axial side (L2), and the bearing (B3) that rotatably supports the transmission member (3) with respect to the case (9) is preferably arranged to support the axial load acting on the transmission member (3) by the engagement pressure in the axial direction (L) by the friction engagement device (4).

[0065] With this configuration, the axial load caused by the engagement pressure of the friction engagement device can be supported by the bearings of the transmission member, making it easier to simplify the support structure of the friction engagement device and the transmission member.

[0066] Furthermore, in the vehicle drive unit (1), the power transmission section (35) between the transmission member (3) and the power transmission mechanism (5) is a meshing section of helical gears, and it is preferable that the orientation of the helical teeth of the helical gears is set such that, in the rotational direction of the power transmission section (35) when the vehicle is moving forward, the direction of the axial load acting on the transmission member (3) due to the meshing of the helical gears is opposite to the direction of the axial load acting on the transmission member (3) due to the engagement pressure of the friction engagement device (4).

[0067] With this configuration, at least a portion of the axial load due to the engagement pressure of the friction engagement device (4) can be offset by the axial load generated by the meshing of the helical teeth in the power transmission section (35), thereby reducing the load on the bearing (B3) of the transmission member (3). [Explanation of symbols]

[0068] 1: Vehicle drive unit, 2: Rotating electric machine, 3: Transmission member, 4: Friction engagement device, 5: Power transmission mechanism, 6: Counter gear mechanism, 8: Regulating structure, 9: Case, 21: Rotor, 29: Input member, 35: Power transmission section, 40: Friction engagement member, 41: First friction engagement member, 42: Second friction engagement member, 61: First counter gear, 62: Second counter gear, 77: Output member, 80: Seal member, 81 : First sealing member, 82: Second sealing member, 83: Compartment, 94: Engaging member housing chamber, 95: Transmission mechanism housing chamber, A1: First shaft (rotation axis of the rotor), A2: Second shaft (separate shaft from the rotor), B3: Transmission bearing (bearing that rotatably supports the transmission member relative to the case), L: Axial direction, L1: First axial side, L2: Second axial side, R: Radial direction, R1: Inner radial direction (inner radial side), W: Wheel

Claims

1. Rotating electric machines and, An input member is arranged coaxially with the rotor of the aforementioned rotating electric machine and rotates in conjunction with the rotor, A hollow transmission member arranged coaxially with the rotor, A friction engagement device provided in the power transmission path between the input member and the transmission member, An output member, which is positioned on a separate shaft from the rotor and is driven and connected to the wheel, A power transmission mechanism that transmits driving force between the transmission member and the output member, A vehicle drive system comprising a case that forms an engagement member housing chamber in which a friction engagement member of the friction engagement device is housed, and a transmission mechanism housing chamber in which the power transmission mechanism is housed, The direction along the rotation axis of the rotor is defined as the axial direction, the direction perpendicular to the rotation axis is defined as the radial 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. The engagement member housing chamber is positioned on the first axial side with respect to the rotor. The input member is inserted into the radially inner side of the transmission member, The power transmission section between the transmission member and the power transmission mechanism is positioned between the rotor and the engagement member housing chamber in the axial direction and is housed in the transmission mechanism housing chamber. A restricting structure is provided between the engagement member housing chamber and the transmission mechanism housing chamber to prevent oil from the transmission mechanism housing chamber from entering the engagement member housing chamber. The aforementioned regulatory structure is, A partition portion which separates the engagement member housing chamber and the transmission mechanism housing chamber in the case, A first sealing member that seals the space between the input member and the transmission member on the first axial side of the power transmission section, A vehicle drive device comprising a second sealing member that seals the space between the transmission member and the partition on the first axial side relative to the power transmission section.

2. The power transmission mechanism includes a counter gear mechanism having a large-diameter first counter gear that meshes with a gear that rotates integrally with the transmission member, and a small-diameter second counter gear that rotates integrally with the first counter gear. The axial arrangement region of the engagement member housing chamber and the axial arrangement region of the second counter gear overlap. The vehicle drive device according to claim 1, wherein the engaging member housing chamber and the first counter gear overlap in an axial view along the axial direction.

3. The friction engagement member comprises a first friction engagement member that rotates integrally with the transmission member and a second friction engagement member that rotates integrally with the input member. The friction engagement device engages the first friction engagement member and the second friction engagement member by pressing the first friction engagement member and the second friction engagement member from the first axial side to the second axial side. The vehicle drive device according to claim 1 or 2, wherein the bearing that rotatably supports the transmission member with respect to the case is arranged to support the axial load acting on the transmission member by the axial engagement pressure of the friction engagement device.

4. The power transmission section between the transmission member and the power transmission mechanism is the meshing section of the helical gear, The vehicle drive device according to claim 3, wherein the orientation of the helical teeth of the helical gear is set such that, in the rotational direction of the power transmission section when the vehicle is moving forward, the direction of the axial load acting on the transmission member due to the meshing of the helical gear is opposite to the direction of the axial load acting on the transmission member due to the engagement pressure of the friction engagement device.

Images