Vehicle drive systems

Abstract

This provides a vehicle drive system that is advantageous for ensuring a long drive shaft length. [Solution] The vehicle drive system comprises a rotating electric machine having a hollow output shaft, a differential gear that distributes the driving force output by the rotating electric machine to a pair of drive wheels, a case that houses the rotating electric machine and the differential gear, an intermediate shaft that extends along the axial direction of the rotating electric machine through a through hole in the output shaft and has one end connected to the differential gear, and a drive shaft inboard that fits onto the other end of the intermediate shaft. The intermediate shaft has a first flow path that extends along the axial direction. The case has a second flow path. The fitting portion between the intermediate shaft and the drive shaft inboard has a third flow path that allows lubricating fluid to flow between the first and second flow paths.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a vehicle drive device.

Background Art

[0002] Patent Document 1 discloses a vehicle drive device in which a rotary electric machine and a differential gear are arranged coaxially. In this type of drive device, the output shaft of the rotary electric machine is hollow, and an intermediate shaft extends along the axial direction of the rotary electric machine within the through-hole of the output shaft. One end of the intermediate shaft is connected to the differential gear, and the other end of the intermediate shaft is fitted into the drive shaft inboard.

[0003] A flow path through which a lubricating fluid for lubricating lubrication target parts such as a rotary electric machine flows is provided in the intermediate shaft. The flow path provided in the intermediate shaft is configured to supply the lubricating fluid toward the lubrication target part at the position where the lubrication target part exists. Lubricating fluid is supplied to the flow path provided in the intermediate shaft from a flow path provided in a case that houses the rotary electric machine and the differential gear.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the drive system described in Patent Document 1, one end of the flow path of the intermediate shaft opens to the outer surface of the intermediate shaft, and the flow path of the case connects to the flow path of the intermediate shaft at the opening. The fitting portion between the intermediate shaft and the drive shaft inboard is configured so as not to interfere with the flow path of the intermediate shaft. That is, the drive shaft inboard is positioned outside the connection point of the flow path with respect to the rotating electric machine and differential gear. With such a structure, under the condition that the vehicle width is constant, it may not be possible to secure a sufficient overall length of the drive shaft, which may lead to problems such as a narrowed range of motion of the wheels. This specification provides a vehicle drive system that is advantageous in securing a long overall length of the drive shaft. [Means for solving the problem]

[0006] A vehicle drive system disclosed herein may include a rotating electric machine having a hollow output shaft, a differential gear for distributing the driving force output by the rotating electric machine to a pair of drive wheels, a case housing the rotating electric machine and the differential gear, an intermediate shaft extending axially along the rotating electric machine through a through-hole in the output shaft and having one end connected to the differential gear, and a drive shaft inboard fitted to the other end of the intermediate shaft. The intermediate shaft may have a first flow path extending axially. The case may have a second flow path. The fitting portion of the intermediate shaft and the drive shaft inboard may have a third flow path for circulating lubricant between the first and second flow paths. The direction of the lubricant flowing through the third flow path is not particularly limited. For example, the lubricant may flow from the second flow path through the third flow path to the first flow path.

[0007] In the above-described vehicle drive system, a third flow path is provided at the fitting portion between the intermediate shaft and the drive shaft inboard. This allows the drive shaft inboard to be positioned closer to the rotating electric machine and differential gear. The above-described vehicle drive system has a structure that is advantageous for ensuring a longer drive shaft length. [Brief explanation of the drawing]

[0008] [Figure 1] This diagram provides a schematic overview of the vehicle's configuration. [Figure 2] This is a diagram showing the skeleton of the drive system installed in the vehicle. [Figure 3] This figure schematically shows a cross-sectional view of the main part near the fitting portion between the intermediate shaft and the drive shaft inboard in one embodiment. [Figure 4] This figure schematically shows a cross-sectional view of the main part near the fitting portion between the intermediate shaft and the drive shaft inboard in one embodiment. [Figure 5] This figure schematically shows a perspective view of the ring member incorporated into the embodiment shown in Figure 4. [Figure 6] This figure schematically shows a cross-sectional view of the main part of a differential gear in one embodiment. [Modes for carrying out the invention]

[0009] The following describes the drive system mounted on the vehicle, referring to the drawings. Here, the directions in some of the drawings correspond to the vehicle's direction. Direction FR indicates the front in the vehicle's longitudinal direction, and direction RR indicates the rear in the vehicle's longitudinal direction. Direction LH indicates the left in the vehicle's lateral direction, and direction RH indicates the right in the vehicle's lateral direction. Direction UP indicates the upward in the vehicle's vertical direction, and direction DW indicates the downward in the vehicle's vertical direction.

[0010] Figure 1 shows the configuration of Vehicle 1. Vehicle 1 is a vehicle that has at least a rotating electric machine as one of its drive sources, and may be, for example, an electric vehicle, a hybrid vehicle, or a fuel cell vehicle.

[0011] Vehicle 1 comprises a battery pack 2 mounted beneath the floor and a pair of drive units 3. The battery pack 2 supplies power to each of the pair of drive units 3. One of the pair of drive units 3 uses the supplied power to drive the front wheels FW, and the other of the pair of drive units 3 uses the supplied power to drive the rear wheels RW. Although vehicle 1 is exemplified as a four-wheel drive vehicle, it may also be a two-wheel drive vehicle equipped with only one of the pair of drive units 3. The pair of drive units 3 have a common structure. Hereafter, the pair of drive units 3 will be described without distinction.

[0012] The drive unit 3 comprises a rotating electric machine 4, a transmission device 5, a power control unit 6, and a case 7. The rotating electric machine 4, the transmission device 5, and the power control unit 6 are housed within the case 7. The power control unit 6 is positioned adjacent to the rotating electric machine 4 and the transmission device 5 in the longitudinal direction of the vehicle (rear in this example). The power control unit 6 converts the power supplied from the battery pack 2 from direct current to alternating current and supplies it to the rotating electric machine 4. The rotating electric machine 4 generates driving force based on the alternating current power supplied from the power control unit 6. The transmission device 5 amplifies the driving force generated by the rotating electric machine 4 into torque and then distributes it to the left and right wheels.

[0013] The rotating electric machine 4 and the transmission device 5 are arranged coaxially. As a result, the vertical size of the case 7 housing the rotating electric machine 4 and the transmission device 5 is reduced. Consequently, the case 7 is positioned so that, when viewed from the left or right direction of the vehicle, it fits within the range of the corresponding wheels FW and RW. As a result, for example, at the front of the vehicle 1, the degree of freedom in arranging various mechanical components, such as the radiator and the air conditioning control system, is improved, and a larger user space can be secured. Furthermore, at the rear of the vehicle 1, for example, a larger trunk space can be secured, or the range of the rear seat reclining angle can be widened.

[0014] Figure 2 shows a skeleton diagram of the drive unit 3, including the rotating electric machine 4 and the transmission device 5 housed in the case 7. In this example, the rotating electric machine 4 is located on the right side of the case 7, and the transmission device 5 is located on the left side of the case 7. Alternatively, the transmission device 5 may be located on the right side of the case 7, and the rotating electric machine 4 on the left side of the case 7. In the following explanation, for convenience, the names of the components may include left-right directions, but such designations do not limit the position of the components.

[0015] The rotating electric machine 4 comprises a stator core 12, a rotor 14, and an output shaft 16. The stator core 12 is fixed to the case 7. The rotor 14 is supported by the case 7 so as to be rotatable around the rotation axis of the rotating electric machine 4. The output shaft 16 is connected to the rotor 14 and rotates together with the rotor 14. The output shaft 16 is hollow and has a through hole 18 that extends along the rotation axis of the rotating electric machine 10.

[0016] The transmission device 5 comprises a planetary gear section 20 and a differential gear 30. The planetary gear section 20 reduces the rotation of the output shaft 16 of the rotating electric machine 4. The differential gear 30 distributes the driving force of the rotating electric machine 4 transmitted via the planetary gear section 20 to the right wheel 8 and the left wheel 9. The rotating electric machine 4, the planetary gear section 20, and the differential gear 30 are arranged coaxially. Note that the configuration of the transmission device 5 described below is just one example, and other types of configurations can be adopted as appropriate.

[0017] The planetary gear unit 20 includes a sun gear 22, a plurality of stepped pinion gears 24, a ring gear 26, and a carrier 28. The sun gear 22 is connected to the output shaft 16 of the rotary electric machine 4 and rotates integrally with the output shaft 16. Each of the plurality of stepped pinion gears 24 has a large-diameter pinion gear P1 and a small-diameter pinion gear P2 having a smaller diameter than the large-diameter pinion gear P1. The large-diameter pinion gear P1 meshes with the sun gear 22. The small-diameter pinion gear P2 meshes with the ring gear 26. The ring gear 26 is fixed to the case 7. The carrier 28 rotatably supports each of the plurality of stepped pinion gears 24. Thus, in the planetary gear unit 20, the sun gear 22 is an input element, the ring gear 26 is a reaction force element, and the carrier 28 is an output element.

[0018] The differential gear 30 includes a differential case 31 and a differential gear mechanism 32. The differential case 31 is supported by the case 7 so as to be rotatable around the rotation axis of the rotary electric machine 4. The differential case 31 is connected to the carrier 28 of the planetary gear unit 20 and rotates integrally with the carrier 28. The differential gear mechanism 32 is housed in the differential case 31.

[0019] The differential gear mechanism 32 includes a pinion shaft 33, a pair of differential pinion gears 34, 35, a right side gear 36, and a left side gear 37.

[0020] The pinion shaft 33 is connected to the differential case 31 and rotates integrally with the differential case 31. The pinion shaft 33 extends in the differential case 31 along a direction orthogonal to the rotation axis direction of the rotating electric machine 4. Each of the pair of differential pinion gears 34, 35 is supported by the pinion shaft 33 so as to be rotatable around the axis of the pinion shaft 33. The right side gear 36 is a member that outputs a driving force to the right wheel 8 and meshes with each of the pair of differential pinion gears 34, 35. The left side gear 37 is a member that outputs a driving force to the left wheel 9 and meshes with each of the pair of differential pinion gears 34, 35.

[0021] The drive device 3 further includes an intermediate shaft 40, a right drive shaft 50 connected to the right wheel 8, and a left drive shaft 60 connected to the left wheel 9.

[0022] The intermediate shaft 40 extends in the through-hole 18 of the output shaft 16 along the rotation axis direction of the rotating electric machine 4. The left end portion of the intermediate shaft 40 is connected to the right side gear 36 of the differential gear 30, and the right end portion of the intermediate shaft 40 is connected to the right drive shaft 50.

[0023] The right drive shaft 50 has a drive shaft inboard 52, an intermediate drive shaft 54, and a drive shaft outboard 56. The drive shaft inboard 52 is the left end portion on the side inserted into the case 7 among both end portions in the axial direction of the right drive shaft 50, and refers to the portion from the constant velocity joint to the left end face. The drive shaft outboard 56 is the right end portion on the side connected to the right wheel 8 among both end portions in the axial direction of the right drive shaft 50, and refers to the portion from the constant velocity joint to the right end face. The drive shaft inboard 52 of the right drive shaft 50 is connected to the right side gear 36 of the differential gear 30 via the intermediate shaft 40. The driving force output by the right side gear 36 is transmitted to the right drive shaft 50 via the intermediate shaft 40.

[0024] The left drive shaft 60 has a drive shaft inboard 62, an intermediate drive shaft 64, and a drive shaft outboard 66. The drive shaft inboard 62 is the right end of the left drive shaft 60 in the axial direction that is inserted into the case 7, and refers to the portion from the constant velocity joint to the right end face. The drive shaft outboard 66 is the left end of the left drive shaft 60 in the axial direction that is connected to the left wheel 9, and refers to the portion from the constant velocity joint to the left end face. The drive shaft inboard 62 of the left drive shaft 60 is connected to the left side gear 37 of the differential gear 30. The driving force output by the left side gear 37 is transmitted directly to the left drive shaft 60.

[0025] In the drive unit 3, a passage for lubricating fluid to lubricate and cool the parts to be lubricated, such as the rotating electric machine 4 and the transmission device 5, is provided in the intermediate shaft 40. The passage in the intermediate shaft 40 is configured to supply lubricating fluid to the parts to be lubricated at the location where the parts to be lubricated are located. The lubricating fluid is drawn in by a pump or the like from a reservoir located at the bottom of the case 7, cooled by a heat exchanger or the like, and then supplied to the passage in the intermediate shaft 40. In the drive unit 3, the cooled lubricating fluid is supplied to the passage in the intermediate shaft 40 via the passage in the case 7.

[0026] Figure 3 shows a cross-sectional view of the vicinity of the fitting portion between the intermediate shaft 40 and the drive shaft inboard 52 of the right drive shaft 50. Here, the "fitting portion" is the part formed by both the right end of the intermediate shaft 40 and the left end of the drive shaft inboard 52, and is located between the right end face 41 of the intermediate shaft 40 and the left end face 51 of the drive shaft inboard 52 in the direction of rotation axis.

[0027] An insertion hole 42 into which the drive shaft inboard 52 is inserted is provided at the right end of the intermediate shaft 40. Internal spline teeth 44 are formed on the inner circumferential surface 43 of the intermediate shaft 40 that defines the insertion hole 42. External spline teeth 55 are formed on the outer circumferential surface 53 of the drive shaft inboard 52. The intermediate shaft 40 and the drive shaft inboard 52 are spline-fitted by the internal spline teeth 44 of the intermediate shaft 40 and the external spline teeth 55 of the drive shaft inboard 52. The left end face 51 of the drive shaft inboard 52 faces the bottom face 45 of the insertion hole 42. The left end face 51 of the drive shaft inboard 52 and the bottom face 45 of the insertion hole 42 are separated. When the left end face 51 of the drive shaft inboard 52 and the bottom face 45 of the insertion hole 42 are separated, lubricating fluid can be supplied to the spline-fitted portion formed by the internal spline teeth 44 of the intermediate shaft 40 and the external spline teeth 55 of the drive shaft inboard 52.

[0028] The intermediate shaft 40 is provided with a first flow path 82 that extends along the axial direction of the intermediate shaft 40. One end of the first flow path 82 opens to the bottom surface 45 of the insertion hole 42. The intermediate shaft 40 is provided with one or more supply holes that extend from the first flow path 82 to the outer surface in a direction perpendicular to the axial direction of the intermediate shaft 40 at the location where the part to be lubricated is located. The lubricating fluid supplied to the first flow path 82 is supplied to the part to be lubricated from one or more supply holes.

[0029] Case 7 is provided with a passage opening 72 through which the drive shaft inboard 52 passes. A portion of the drive shaft inboard 52 enters the case 7 and engages with the intermediate shaft 40 within the case 7. Case 7 is provided with a second passage 84 located above the passage opening 72. One end of the second passage 84 opens onto the surface defining the passage opening 72.

[0030] A third passage 86 is provided at the fitting portion between the intermediate shaft 40 and the drive shaft inboard 52. The third passage 86 has a first communication passage 181 provided in the intermediate shaft 40 and a second communication passage 182 provided in the drive shaft inboard 52.

[0031] The first communication channel 181 is a through-hole that penetrates the intermediate shaft 40 radially through the portion of the intermediate shaft 40 that is located around the insertion hole 42. One end of the first communication channel 181 opens to the outer circumferential surface 46 of the intermediate shaft 40, and the other end of the first communication channel 181 opens to the inner circumferential surface 43 of the intermediate shaft 40. When viewed radially along the intermediate shaft 40, the area where the second channel 84 exists at the passage opening 72 of the case 7 overlaps with the area where the first communication channel 181 exists on the outer circumferential surface 46 of the intermediate shaft 40.

[0032] The second communication passage 182 is a through-hole extending within the drive shaft inboard 52. One end of the second communication passage 182 opens to the outer circumferential surface 53 of the drive shaft inboard 52, and the other end of the second communication passage 182 opens to the left end surface 51 of the drive shaft inboard 52. The first communication passage 181 and the second communication passage 182 face each other between the inner circumferential surface 43 of the intermediate shaft 40 and the outer circumferential surface 53 of the drive shaft inboard 52.

[0033] The arrows shown within each of the passages 82, 84, and 86 indicate the direction of the lubricating fluid flowing through each passage. As described above, a third passage 86, consisting of a first communication passage 181 and a second communication passage 182, is provided at the fitting portion between the intermediate shaft 40 and the drive shaft inboard 52. The lubricating fluid supplied from the second passage 84 of the case 7 flows through the third passage 86 and is led to the first passage 82 of the intermediate shaft 40.

[0034] If a third flow path 86 is provided at the fitting portion between the intermediate shaft 40 and the drive shaft inboard 52, the drive shaft inboard 52 can be positioned closer to the rotating electric machine 4 and the differential gear 30. This makes it possible to ensure a longer overall length of the right drive shaft 50 under the condition that the vehicle width is constant, thereby widening the range of motion of the wheels.

[0035] In the above description, an example was given in which the left end face 51 of the drive shaft inboard 52 and the bottom face 45 of the insertion hole 42 are separated. However, the left end face 51 of the drive shaft inboard 52 and the bottom face 45 of the insertion hole 42 may be in contact. Also, in the above description, an example was given in which lubricating fluid flows through a second communication passage 182 formed within the drive shaft inboard 52. In addition to, or instead of, this second communication passage 182, a communication passage may be provided between the inner circumferential surface 43 of the intermediate shaft 40 and the outer circumferential surface 53 of the drive shaft inboard 52. This communication passage may be formed by the gap between the inner circumferential surface 43 of the intermediate shaft 40 and the outer circumferential surface 53 of the drive shaft inboard 52. If a second communication channel 182 is formed within the drive shaft inboard 52, lubricating fluid that has leaked out from the connection point between the first communication channel 181 and the second communication channel 182 may flow into the additional communication channel between the inner circumferential surface 43 of the intermediate shaft 40 and the outer circumferential surface 53 of the drive shaft inboard 52. A spline fitting portion exists between the inner circumferential surface 43 of the intermediate shaft 40 and the outer circumferential surface 53 of the drive shaft inboard 52, consisting of the inner spline teeth 44 of the intermediate shaft 40 and the outer spline teeth 55 of the drive shaft inboard 52. However, a gap is formed between the top surface of one spline tooth and the bottom surface of the other spline tooth, and lubricating fluid can flow through this gap. If a communication channel is provided between the inner circumferential surface 43 of the intermediate shaft 40 and the outer circumferential surface 53 of the drive shaft inboard 52, the amount of lubricating fluid flowing through the second communication channel 182 can be reduced. This makes it possible to design the system in a way that reduces the cross-sectional area of ​​the second communication channel 182, or even eliminates the second communication channel 182 altogether. As a result, a decrease in the strength of the drive shaft inboard 52 can be suppressed.

[0036] As shown in Figures 4 and 5, a hollow ring member 90 may be provided between the inner circumferential surface 43 of the intermediate shaft 40 and the outer circumferential surface 53 of the drive shaft inboard 52. The ring member 90 is press-fitted into the insertion hole 42 of the intermediate shaft 40. To improve the fixing force between the ring member 90 and the intermediate shaft 40, the outer circumferential surface 91 of the ring member 90 may be knurled. Alternatively, mechanical structures such as splines may be formed on the outer circumferential surface 91 of the ring member 90 and the inner circumferential surface 43 of the intermediate shaft 40.

[0037] Internal spline teeth 93 are formed on the inner circumferential surface 92 of the ring member 90. The ring member 90 and the drive shaft inboard 52 are spline-fitted by the internal spline teeth 93 of the ring member 90 and the external spline teeth 55 of the drive shaft inboard 52.

[0038] A groove 95 is formed on the outer circumferential surface 91 of the ring member 90. The groove 95 does not extend between the end faces of the ring member 90 along the axial direction of the ring member 90. The groove 95 extends from a position facing the first communication channel 181 provided in the intermediate shaft 40 to one end face 94. The end face 94 is the end face facing the bottom surface 45 of the insertion hole 42 of the intermediate shaft 40.

[0039] With such a ring member 90 provided, the lubricating fluid supplied from the second passage 84 of the case 7 flows through the groove 95 of the ring member 90 and is guided to the first passage 82 of the intermediate shaft 40. Therefore, it is not necessary to form a communication passage within the drive shaft inboard 52, and thus a decrease in the strength of the drive shaft inboard 52 can be suppressed.

[0040] Figure 6 shows a cross-sectional view of the differential gear 30. The left end of the intermediate shaft 40 is spline-fitted with the right side gear 36. The left end of the intermediate shaft 40 passes through the right side gear 36, and the left end face 47 of the intermediate shaft 40 faces the pinion shaft 33. The first flow path 82 provided in the intermediate shaft 40 opens at the left end face 47 of the intermediate shaft 40.

[0041] The drive shaft inboard 62 of the left drive shaft 60 is spline-fitted with the left side gear 37. The drive shaft inboard 62 passes through the left side gear 37, and the right end face 61 of the drive shaft inboard 62 faces the pinion shaft 33. A fourth passage 88 is provided in the drive shaft inboard 62. One end of the fourth passage 88 opens to the right end face 61 of the drive shaft inboard 62. The other end of the fourth passage 88 opens to the outer circumferential surface 63 of the drive shaft inboard 62 outside the differential case 31.

[0042] The pinion shaft 33 is provided with an intermediate hole 38. The intermediate hole 38 is a through hole that penetrates the pinion shaft 33 in a direction perpendicular to the axial direction of the pinion shaft 33, that is, along the axial direction of the intermediate shaft 40. When viewed along the axial direction of the intermediate shaft 40, the range of the first flow path 82 on the left end face 47 of the intermediate shaft 40 is within the range where the intermediate hole 38 exists. Also, when viewed along the axial direction of the intermediate shaft 40, the range of the fourth flow path 88 on the right end face 61 of the drive shaft inboard 62 is within the range where the intermediate hole 38 exists. With the intermediate hole 38 provided in this positional relationship, the lubricating fluid discharged from the first flow path 82 can pass through the intermediate hole 38 and reach the fourth flow path 88. The lubricating fluid that flows into the fourth flow path 88 is discharged from an opening on the outer circumferential surface 63 of the drive shaft inboard 62 and supplied to a lubrication target part, such as an oil seat.

[0043] The first flow path 82 of the intermediate shaft 40 further includes a constricted section 81 with a narrower cross-sectional area, and a discharge port 83 provided between the constricted section 81 and the left end face 47 of the intermediate shaft 40. The constricted section 81 is located near the left end face 47 of the intermediate shaft 40. The constricted section 81 is located inside the differential case 31, and more specifically, inside the right side gear 36. The discharge port 83 is configured such that its cross-sectional area gradually increases from the constricted section 81 to the left end face 47 of the intermediate shaft 40. With this structure, lubricating fluid is forcefully discharged from the discharge port 83, allowing it to flow efficiently into the fourth flow path 88.

[0044] The above example describes a scenario in which lubricating fluid flows from the right drive shaft 50 through the intermediate shaft 40 to the left drive shaft 60. Alternatively, lubricating fluid may flow from the left drive shaft 60 through the intermediate shaft 40 to the right drive shaft 50.

[0045] The embodiments disclosed herein are summarized below. Note that the technical elements described below are independent technical elements that exhibit technical usefulness individually or in various combinations.

[0046] (Aspect 1) A vehicle drive system comprising: a rotating electric machine having a hollow output shaft; a differential gear for distributing the driving force output by the rotating electric machine to a pair of drive wheels; a case housing the rotating electric machine and the differential gear; an intermediate shaft extending along the axial direction of the rotating electric machine through a through hole in the output shaft, with one end connected to the differential gear; and a drive shaft inboard fitted to the other end of the intermediate shaft, wherein the intermediate shaft has a first passage extending along the axial direction, the case has a second passage, and the fitting portion of the intermediate shaft and the drive shaft inboard has a third passage for circulating lubricating fluid between the first and second passages.

[0047] (Aspect 2) In the vehicle drive system described in Embodiment 1, the case may have a passage opening through which the drive shaft inboard passes, and the second passage and the third passage may be connected at the passage opening.

[0048] (Aspect 3) In the vehicle drive system according to embodiment 1 or 2, the intermediate shaft may have an insertion hole at the other end into which the drive shaft inboard is inserted, the end face of the drive shaft inboard may face the bottom surface of the insertion hole, and the first flow path may open to the bottom surface of the insertion hole.

[0049] (Aspect 4) In the vehicle drive device according to Embodiment 3, the third passage may include a first communication passage provided in the intermediate shaft, one end of which opens to the outer circumferential surface of the intermediate shaft and the other end of which opens to the inner circumferential surface of the intermediate shaft defining the insertion hole, and a second communication passage provided in the drive shaft inboard, one end of which opens to the outer circumferential surface of the drive shaft inboard and the other end of which opens to the end face of the drive shaft inboard, and the other end of the first communication passage and the one end of the second communication passage may face each other.

[0050] (Appendix 5) In the vehicle drive system according to Embodiment 4, the third passage is a third communication passage provided between the inner circumferential surface of the intermediate shaft and the outer circumferential surface of the drive shaft inboard, and may further have a third communication passage that extends from a position opposite the other end of the first communication passage to the end face of the drive shaft inboard.

[0051] (Aspect 6) In the vehicle drive system according to Embodiment 3, the third passage may include a first communication passage provided in the intermediate shaft, one end of which opens to the outer circumferential surface of the intermediate shaft and the other end of which opens to the inner circumferential surface of the intermediate shaft defining the insertion hole, and a third communication passage provided between the inner circumferential surface of the intermediate shaft and the outer circumferential surface of the drive shaft inboard, the third communication passage extending from a position opposite to the other end of the first communication passage to the end face of the drive shaft inboard.

[0052] (Aspect 7) In the vehicle drive system according to embodiment 5 or 6, the intermediate shaft and the drive shaft inboard may be spline-fitted by internal spline teeth provided on the inner circumferential surface of the intermediate shaft and external spline teeth provided on the outer circumferential surface of the drive shaft inboard, and at least a portion of the third communication passage may be formed by the gap between the internal spline teeth and the external spline teeth.

[0053] (Pattern 8) The vehicle drive device according to embodiment 3 may further include a hollow ring member provided between the inner circumferential surface of the intermediate shaft defining the insertion hole and the outer circumferential surface of the drive shaft inboard, the end face of the ring member facing the bottom surface of the insertion hole, and the third flow path may have a first communication flow path provided in the intermediate shaft, one end of which opens to the outer circumferential surface of the intermediate shaft and the other end of which opens to the inner circumferential surface of the intermediate shaft, and a fourth communication flow path provided in the ring member, the fourth communication flow path extending from a position facing the other end of the first communication flow path to the end face of the ring member.

[0054] (Aspect 9) In the vehicle drive system described in embodiment 8, the fourth communication channel may be a groove provided on the outer circumferential surface of the ring member.

[0055] (Aspect 10) In the vehicle drive system according to embodiment 8 or 9, the ring member may be press-fitted into the insertion hole of the intermediate shaft, and the drive shaft inboard and the ring member may be spline-fitted.

[0056] Although embodiments have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness in itself. [Explanation of Symbols]

[0057] 7: Case, 16: Output shaft, 18: Through hole, 40: Intermediate shaft, 52: Drive shaft inboard, 72: Through port, 82: First channel, 84: Second channel, 86: Third channel, 181: First connecting channel, 182: Second connecting channel

Claims

1. A rotating electric machine having a hollow output shaft, A differential gear that distributes the driving force output by the aforementioned rotating electric machine to a pair of drive wheels, A case housing the aforementioned rotating electric machine and the aforementioned differential gear, An intermediate shaft extends through the through hole of the output shaft along the axial direction of the rotating electric machine, with one end connected to the differential gear, A drive shaft inboard is fitted to the other end of the intermediate shaft, It is equipped with, The intermediate shaft has a first flow path extending along the axial direction, The aforementioned case has a second flow path, A vehicle drive system wherein the fitting portion between the intermediate shaft and the drive shaft inboard has a third passage for circulating lubricating fluid between the first passage and the second passage.

2. The case has a passage opening through which the drive shaft inboard passes, The vehicle drive device according to claim 1, wherein the second flow path and the third flow path are connected at the passage opening.

3. The intermediate shaft has an insertion hole at the other end into which the drive shaft inboard is inserted. The end face of the drive shaft inboard faces the bottom surface of the insertion hole, The vehicle drive device according to claim 1, wherein the first flow path opens to the bottom surface of the insertion hole.

4. The third channel is, A first communication channel provided in the intermediate shaft, wherein one end opens to the outer circumferential surface of the intermediate shaft and the other end opens to the inner circumferential surface of the intermediate shaft defining the insertion hole, The drive shaft inboard has a second communication channel, one end of which opens to the outer circumferential surface of the drive shaft inboard and the other end of which opens to the end surface of the drive shaft inboard. The vehicle drive device according to claim 3, wherein the other end of the first communication channel and the one end of the second communication channel face each other.

5. The third channel is, The vehicle drive device according to claim 4, further comprising a third communication passage provided between the inner circumferential surface of the intermediate shaft and the outer circumferential surface of the drive shaft inboard, the third communication passage extending from a position opposite to the other end of the first communication passage to the end face of the drive shaft inboard.

6. The third channel is, A first communication channel provided in the intermediate shaft, wherein one end opens to the outer circumferential surface of the intermediate shaft and the other end opens to the inner circumferential surface of the intermediate shaft defining the insertion hole, The vehicle drive device according to claim 3, comprising a third communication passage provided between the inner circumferential surface of the intermediate shaft and the outer circumferential surface of the drive shaft inboard, the third communication passage extending from a position opposite to the other end of the first communication passage to the end face of the drive shaft inboard.

7. The intermediate shaft and the drive shaft inboard are spline-fitted by internal spline teeth provided on the inner circumferential surface of the intermediate shaft and external spline teeth provided on the outer circumferential surface of the drive shaft inboard. The vehicle drive device according to claim 5 or 6, wherein at least a portion of the third communication channel is formed by the gap between the inner spline teeth and the outer spline teeth.

8. The system further comprises a hollow ring member provided between the inner circumferential surface of the intermediate shaft defining the insertion hole and the outer circumferential surface of the drive shaft inboard, The end face of the ring member faces the bottom surface of the insertion hole, The third channel is, A first communication channel provided in the intermediate shaft, wherein one end of the first communication channel opens to the outer circumferential surface of the intermediate shaft and the other end opens to the inner circumferential surface of the intermediate shaft, The vehicle drive device according to claim 3, further comprising a fourth communication channel provided in the ring member, the fourth communication channel extending from a position opposite to the other end of the first communication channel to the end face of the ring member.

9. The vehicle drive device according to claim 8, wherein the fourth communication channel is a groove provided on the outer circumferential surface of the ring member.

10. The ring member is press-fitted into the insertion hole of the intermediate shaft. The vehicle drive device according to claim 8 or 9, wherein the drive shaft inboard and the ring member are spline-fitted.

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