JP7619132B2 - Rotating electric machine and vehicle drive device - Google Patents

Description

This disclosure relates to rotating electric machines and vehicle drive devices.

A technology is known in which a power transmission spline (female spline) is formed on the inner peripheral surface of a hollow rotor shaft, a power transmission spline (male spline) is formed on the outer peripheral surface of an input shaft, and the two are spline-fitted together, allowing the rotational torque of a rotating electric machine to be transmitted to the wheels via the input shaft.

JP 2019-129608 A

However, with the above-mentioned conventional technology, it is difficult to stably supply oil to the spline engagement between the input shaft and the rotor shaft.

Therefore, in one aspect, the present disclosure aims to stably supply oil to the spline fitting portion of the rotor shaft.

In one aspect, a rotor includes:
a rotor having a hollow rotor shaft;
an oil passage forming member that forms an oil passage for supplying oil to a hollow interior of the rotor shaft,
the rotor shaft has, on an inner peripheral surface thereof, a dam portion that protrudes radially inward over the entire circumferential direction, and a female spline that meshes with a male spline of a rotating shaft member for transmitting rotational torque,
the oil passage supplies oil between the dam portion and the spline in an axial direction,
A rotating electric machine is provided, in which an inner diameter of the dam portion is smaller than a large diameter of the female spline of the rotor shaft.

In one aspect, the present disclosure makes it possible to steadily supply oil to the spline engagement portion of the rotor shaft.

1 is a skeleton diagram of a vehicle drive system including a rotating electric machine. 1 is a cross-sectional view showing a schematic view of a main part of a rotating electric machine; FIG. 3 is an enlarged view of a portion Q1 in FIG. 2 . FIG. 3 is an enlarged view of a portion Q2 in FIG. 2 . FIG. 3 is an enlarged view of a portion Q3 in FIG. 2 . FIG. 4 is a cross-sectional view of a portion of a spline fitting portion. FIG. 11 is a cross-sectional view showing a fitting portion according to a first modified example. FIG. 8 is an enlarged view of a portion Q4 in FIG. 7 . FIG. 11 is a cross-sectional view showing a fitting portion according to a second modified example.

Below, we will first explain the vehicle drive system 100 to which the rotating electric machine 1 according to this embodiment can be suitably applied, and then explain the details of the rotating electric machine 1 according to this embodiment.

[Entire drive system]
Fig. 1 is a skeleton diagram of a vehicle drive system 100 including a rotating electric machine 1. In Fig. 1, an X direction and an X1 side and an X2 side along the X direction are defined. The X direction is parallel to the direction of a first axis A1 (hereinafter also referred to as the "axial direction").

In the example shown in FIG. 1, the vehicle drive system 100 includes a rotating electric machine 1 that drives the wheels W, and a power transmission mechanism 7 that is provided in a power transmission path that connects the rotating electric machine 1 and the wheels W. The power transmission mechanism 7 includes an input member 3, a counter gear mechanism 4, a differential gear mechanism 5, and left and right output members 6A and 6B.

The input member 3 has an input shaft 31 and an input gear 32. The input shaft 31 is a rotating member that rotates around the first axis A1. The input gear 32 is a gear that transmits the rotational torque (driving force) from the rotating electric machine 1 to the counter gear mechanism 4. The input gear 32 is provided on the input shaft 31 of the input member 3 so as to rotate integrally with the input shaft 31 of the input member 3.

The counter gear mechanism 4 is disposed in the power transmission path between the input member 3 and the differential gear mechanism 5. The counter gear mechanism 4 has a counter shaft 41, a first counter gear 42, and a second counter gear 43.

The counter shaft 41 is a rotating member that rotates around the second axis A2. The second axis A2 extends parallel to the first axis A1. The first counter gear 42 is an input element of the counter gear mechanism 4. The first counter gear 42 meshes with the input gear 32 of the input member 3. The first counter gear 42 is connected to the counter shaft 41 so as to rotate integrally with the counter shaft 41.

The second counter gear 43 is an output element of the counter gear mechanism 4. In this embodiment, as an example, the second counter gear 43 is formed with a smaller diameter than the first counter gear 42. The second counter gear 43 is provided on the counter shaft 41 so as to rotate integrally with the counter shaft 41.

The differential gear mechanism 5 is disposed on a third axis A3, which serves as the axis of rotation. The third axis A3 extends parallel to the first axis A1. The differential gear mechanism 5 distributes the driving force transmitted from the rotating electric machine 1 to the left and right output members 6A and 6B. The differential gear mechanism 5 includes a differential input gear 51, which meshes with the second counter gear 43 of the counter gear mechanism 4. The differential gear mechanism 5 also includes a differential case 52, which houses a pinion shaft, pinion gears, left and right side gears, etc. The left and right side gears are connected to the left and right output members 6A and 6B so as to rotate integrally with them, respectively.

The left and right output members 6A and 6B are drivingly connected to the left and right wheels W, respectively. The left and right output members 6A and 6B transmit the driving force distributed by the differential gear mechanism 5 to the wheels W. The left and right output members 6A and 6B may be composed of two or more members.

In this way, the rotating electric machine 1 drives the wheels W via the power transmission mechanism 7. However, in other embodiments, the vehicle drive system 100 may be configured not to include the power transmission mechanism 7. Also, in other embodiments, other power transmission mechanisms such as a planetary gear mechanism may be used.

[Details of the rotating electric machine]
FIG. 2 is a cross-sectional view showing a schematic view of a main part of the rotating electric machine 1. FIG. 3 is an enlarged view of a Q1 part in FIG. 2. FIG. 4 is an enlarged view of a Q2 part in FIG. 2. FIG. 5 is an enlarged view of a Q3 part in FIG. 2. FIG. 6 is a cross-sectional view of a part of the spline fitting part 70, taken along line A4-A4 in FIG. 5. FIG. 2 defines a Z direction, and a Z1 side and a Z2 side along the Z direction. The Z direction is a direction perpendicular to the axial direction, and corresponds to the up-down direction. Here, the Z1 side is the upper side, and the Z2 side is the lower side. However, the Z direction does not need to be strictly parallel to the direction of gravity, and may be a direction slightly inclined with respect to the direction of gravity. In the following description, the terms radial direction and circumferential direction are based on the first axis A1, and unless otherwise specified, the inner diameter is the inner diameter based on the first axis A1.

The rotating electric machine 1 has a rotor 310 and a stator 320 inside the case 2.

The case 2 may be made of aluminum, for example. The case 2 may be formed by casting or the like. The case 2 includes a motor case 250 and a cover member 252. The case 2 houses the rotating electric machine 1. In the case of the vehicle drive system 100 shown in FIG. 1, the case 2 may further house a power transmission mechanism 7, as shown diagrammatically in FIG. 1.

The motor case 250 forms a motor housing chamber SP1 that houses the rotating electric machine 1. The motor housing chamber SP1 may be an oil-tight space that contains oil for cooling and/or lubricating the rotating electric machine 1 (and/or the power transmission mechanism 7). The motor case 250 has a peripheral wall that surrounds the radial outside of the rotating electric machine 1. The motor case 250 may be realized by combining multiple members. Furthermore, the motor case 250 may be integrated with another case member 254 that forms a gear housing chamber SP2 that houses the power transmission mechanism 7 on the X-direction X1 side.

The cover member 252 is connected to the X2 side of the motor case 250 in the X direction. The cover member 252 is in the form of a cover that covers the X2 side of the motor housing chamber SP1 in the X direction. In this case, the cover member 252 may cover the opening of the motor case 250 on the X2 side in the X direction in such a manner that it completely or almost completely blocks it. Note that a portion of the motor housing chamber SP1 may be formed by the cover member 252.

The cover member 252 is provided with a bearing 240 that rotatably supports the rotor 310. That is, the cover member 252 has a bearing support portion 2524 that supports the bearing 240.

As shown in FIG. 2, the bearing 240 is provided radially outward at the end of the rotor shaft 314 on the X2 side. Specifically, the bearing 240 is supported by the cover member 252 at the radially outward side of the outer race, and the bearing 240 is supported by the outer peripheral surface of the rotor shaft 314 at the radially inward side of the inner race. In a modified example, the bearing 240 may be supported by the cover member 252 at the radially inward side of the inner race, and the bearing 240 may be supported by the inner peripheral surface of the rotor shaft 314 at the radially outward side of the outer race.

2, the cover member 252 includes a circular bottom 2521 centered on the first axis A1, and a peripheral wall 2522 protruding from the outer periphery of the bottom 2521 toward the X1 side in the X direction, and the end face of the peripheral wall 2522 on the X1 side in the X direction is connected to the motor case 250. On the X1 side of the bottom 2521, which has a thickness in the X direction, a cylindrical bearing support 2524 protruding toward the X1 side in the X direction is formed in the central portion (part centered on the first axis A1) when viewed in the axial direction. The bearing support 2524 is formed concentrically with the first axis A1 as its center.

In addition, on the X1 side of the bottom 2521 in the X direction, an axial protrusion 2525 is formed on the radial inside of the cylindrical bearing support portion 2524 at the center (the portion centered on the first axis A1) when viewed in the axial direction, as shown in FIG. 2. The axial protrusion 2525 is formed in the center (the portion centered on the first axis A1) on the X1 side of the bottom 2521 in the X direction so as to protrude to the X1 side in the X direction.

The cover member 252 is formed with a cover oil passage 80, a first oil passage 81, and a second oil passage 82.

The cover oil passage 80 is formed in the bottom 2521 of the cover member 252. The cover oil passage 80 is connected to the discharge side of an oil pump (not shown). In this case, oil discharged from the oil pump is supplied to the cover oil passage 80. The oil pump may be a mechanical type or an electric type driven by an electric motor.

The first oil passage 81 is formed in the axial protrusion 2525 of the cover member 252 and extends linearly in the axial direction. The end of the first oil passage 81 on the X2 side in the X direction communicates with the cover oil passage 80, and the end on the X1 side in the X direction is open. The first oil passage 81 on the X1 side in the X direction extends to the hollow interior 314A of the rotor shaft 314. As shown in FIG. 3, the center axis I1 of the first oil passage 81 may be offset upward with respect to the first axis A1 so that the distance L1 (see FIG. 2) to the landing position P1 of the oil discharged from the first oil passage 81 can be made relatively long.

The second oil passage 82 is formed in the axial protrusion 2525 of the cover member 252 and communicates with the cover oil passage 80 via the first oil passage 81. The second oil passage 82 branches off from the first oil passage 81 and extends diagonally downward toward the X1 side in the X-direction.

The rotor 310 comprises a rotor core 312 and a rotor shaft 314.

The rotor core 312 may be made of, for example, laminated steel plates of a magnetic material having a circular shape. A permanent magnet (not shown) may be embedded inside the rotor core 312. Alternatively, the permanent magnet (not shown) may be attached to the outer circumferential surface of the rotor core 312. The arrangement of the permanent magnets (not shown) is optional. The rotor core 312 is fixed to the outer circumferential surface of the rotor shaft 314 and rotates integrally with the rotor shaft 314.

The rotor shaft 314 defines a first axis A1, which is the rotation axis of the rotating electric machine 1. The rotor shaft 314 is rotatably supported by the cover member 252 of the case 2 via a bearing 240 on the X2 side of the portion where the rotor core 312 is fixed. The rotor shaft 314 is rotatably supported by the case 2 via a bearing 241 on the other axial end side (X1 side) of the rotating electric machine 1. In this way, the rotor shaft 314 may be rotatably supported by the case 2 at both axial ends.

As shown in FIG. 5, the rotor shaft 314 is connected to the input shaft 31 on the X1 side in the X direction so as to be capable of transmitting power. In this embodiment, as an example, a spline (hereinafter referred to as the "female spline 71") is formed on the inner peripheral surface of the rotor shaft 314, and is spline-fitted (loose fit) in a manner that it meshes with a spline (hereinafter referred to as the "male spline 72") formed on the outer peripheral surface of the input shaft 31. For example, in this embodiment, as shown in FIG. 6, the meshing of the female spline 71 and the male spline 72 may be realized by a large diameter fitting in which the tooth tip (large diameter surface 721) of the male spline 72 is abutted against the tooth base (large diameter surface 711) of the female spline 71 in the radial direction. Hereinafter, the entire portion where the rotor shaft 314 and the input shaft 31 are connected by spline fitting in this manner is referred to as the "spline fitting portion 70".

In this embodiment, the large diameter r1 of the female spline 71 (= the inner diameter of the large diameter surface 711) is set slightly larger than the inner diameter r2 (see FIG. 3) of the dam portion 89 described later, as shown in FIG. 5 and FIG. 6. The technical significance of this relationship between the inner diameters will be described later. Note that the detailed shape of the female spline 71 (as well as the male spline 72) is arbitrary, as long as the large diameter r1 of the female spline 71 is larger than the inner diameter r2 of the dam portion 89 described later.

In this embodiment, as described above, the large diameter is matched, so the large diameter r1 of the female spline 71 is substantially the same as the large diameter r1' of the male spline 72 (= the inner diameter of the large diameter surface 721). Therefore, in the following description, the "large diameter r1 of the female spline 71" can also be read as the "large diameter r1' of the male spline 72."

The rotor shaft 314 is, for example, in the form of a hollow tube, and has a hollow interior 314A. The hollow interior 314A may extend over the entire axial length of the rotor shaft 314. In this embodiment, as an example, the inner circumferential surface of the rotor shaft 314 has a constant inner diameter r0, except for the section where the female spline 71 is formed. However, in other embodiments, the rotor shaft 314 may have a reduced diameter at both axial ends or one end, in which case the inner circumferential surface of the rotor shaft 314 may have a constant inner diameter r0 in the portion where the rotor core 312 is fixed, and may have an inner diameter smaller than the inner diameter r0 at both axial ends or one end.

The hollow interior 314A of the rotor shaft 314 functions as the axial oil passage 83. That is, oil is supplied to the hollow interior 314A via the cover oil passage 80 described below. This allows the rotor shaft 314 to be cooled, thereby cooling the rotor core 312 (and the permanent magnets, if any) from the radially inner side.

A dam portion 89 for oil storage is formed in the hollow interior 314A of the rotor shaft 314. That is, the rotor shaft 314 has a dam portion 89 on the inner circumferential surface that protrudes radially inward over the entire circumference. In the example shown in FIG. 2, as an example, the dam portion 89 is formed by an annular plug that is fitted into the hollow interior 314A of the rotor shaft 314. However, in a modified example, the dam portion 89 may be realized by the shape of the rotor shaft 314 itself. For example, the rotor shaft 314 may be in a form in which the diameter is reduced at the end on the X2 side in the X direction, and in this case, the step portion of the inner circumferential surface caused by the diameter reduction may realize the dam portion 89. In addition, the convex shape corresponding to the dam portion 89 may be realized by using a flow forming process, a hydroforming process, or the like, or may be realized by using a shaft member of two or more pieces.

The dam portion 89 is preferably disposed on the X2 side in the X-direction relative to the third oil passage 831A described later. This allows oil to be stably supplied to the third oil passage 831A by the oil (described later with reference to FIG. 4, etc.) that accumulates in the dam portion 89. In this case, the dam portion 89 may be formed in a position overlapping the axial protrusion 2525 when viewed in the radial direction, as shown in FIG. 2. This allows the dam portion 89 to be disposed on the X2 side in the X-direction relative to the third oil passage 831A by utilizing the radial space between the axial protrusion 2525 and the inner surface of the rotor shaft 314.

The rotor shaft 314 is formed with a third oil passage 831A and a fourth oil passage 831B in the radial direction, which discharge oil to the coil end portions 322A and 322B of the stator 320, respectively.

The third oil passage 831A has an opening that faces the coil end portion 322A in the radial direction, and supplies oil in the axial oil passage 83 toward the coil end portion 322A. In the example shown in FIG. 2, the third oil passage 831A extends linearly parallel to the radial direction, but may extend linearly in an oblique direction that is slightly inclined relative to the radial direction.

The fourth oil passage 831B has an opening that faces the coil end portion 322B in the radial direction, and supplies oil in the axial oil passage 83 toward the coil end portion 322B. In the example shown in FIG. 2, the fourth oil passage 831B extends linearly parallel to the radial direction, but may extend linearly in a diagonal direction that is slightly inclined relative to the radial direction.

The stator 320 comprises a stator core 321 and a stator coil 322.

The stator core 321 may be made of, for example, a circular magnetic laminated steel plate. Teeth (not shown) protruding radially inward are formed radially on the inner periphery of the stator core 321.

The stator coil 322 may be, for example, a conductor having a rectangular or circular cross section with an insulating coating. The stator coil 322 is wound around the teeth (not shown) of the stator core 321. The stator coils 322 may be, for example, electrically connected in a Y-connection or a Δ-connection in one or more parallel relationships.

The stator coil 322 has coil end portions 322A and 322B that protrude axially outward from the slots of the stator core 321. The coil end portion 322A is located on the X1 side, and the coil end portion 322B is located on the X2 side.

Now, referring to Figures 3, 4, and 5, we will outline the flow of oil in the oil passage structure of this embodiment and explain the principle of oil supply to the spline fitting portion 70. In Figures 3 and 4, the oil 800 that may form on the inner peripheral surface of the rotor shaft 314 due to the centrifugal force caused by the rotation of the rotor shaft 314 is shown by hatching. Also, in Figure 4, the flow of oil is shown by arrows R10 to R32.

The oil supplied to the cover oil passage 80 (see arrow R10) flows into the first oil passage 81 and flows axially through the first oil passage 81 (see arrow R12). A portion of the oil flowing axially through the first oil passage 81 is discharged through the discharge hole 821 of the second oil passage 82 to the landing position P2 on the inner surface of the rotor shaft 314 (or the surface of the oil 800 accumulated on the inner surface) as described above (see arrow R22). In addition, the remaining entirety of the oil flowing axially through the first oil passage 81 is discharged through the discharge hole 811 of the first oil passage 81 to the landing position P1 on the inner surface of the rotor shaft 314 (or the surface of the oil 800 accumulated on the inner surface) as described above (see arrow R21).

Now, while the rotating electric machine 1 is operating, the oil discharged onto the inner circumferential surface of the rotor shaft 314 in this manner flows axially along the inner circumferential surface of the rotor shaft 314 while running along the inner circumferential surface of the rotor shaft 314 due to the centrifugal force that accompanies the rotation of the rotor shaft 314.

In this embodiment, a dam portion 89 is provided on the inner peripheral surface of the rotor shaft 314 on the X2 side in the X direction, so that oil flowing on the X2 side in the X direction is blocked by the dam portion 89. Therefore, in this embodiment, as shown in Figs. 3 and 4, an oil pool of thickness t1 that does not extend radially inward beyond the innermost position of the dam portion 89 is likely to form on the inner peripheral surface of the rotor shaft 314.

In this way, some of the oil that accumulates on the inner surface of the rotor shaft 314 at a thickness t1 is discharged to the coil end portion 322A via the third oil passage 831A (see arrow R31) or to the coil end portion 322B via the fourth oil passage 831B (see arrow R32) by the centrifugal force that accompanies the rotation of the rotor shaft 314. This allows the coil end portion 322A and the coil end portion 322B to be efficiently cooled.

In addition, according to this embodiment, another portion of the oil that accumulates on the inner circumferential surface of the rotor shaft 314 at a thickness t1 is supplied to the spline fitting portion 70. In FIG. 5, the axial line segment that passes through the innermost position of the dam portion 89 (i.e., the line segment of the inner diameter r2) is shown by a two-dot chain line 890.

This allows the oil in the rotor shaft 314 to be steadily supplied as lubricant to the spline engagement portion 70, which is the power transmission portion, and improves the reliability (e.g., wear resistance, etc.) of the spline engagement portion 70.

Specifically, in this embodiment, the inner peripheral surface of the rotor shaft 314 is not provided with a dam portion such as the dam portion 89 (or a dam portion with an inner diameter smaller than that of the dam portion 89) in the section from the third oil passage 831A to the spline fitting portion 70 on the X1 side in the X direction. That is, the rotor shaft 314 has an inner diameter r0 larger than the inner diameter r2 of the dam portion 89 (see FIG. 3) in the section from the third oil passage 831A (or the landing position P1) to the spline fitting portion 70 on the X1 side in the X direction. As a result, when the thickness t1 when the oil pool of the above-mentioned thickness t1 exceeds the dam portion 89 radially inward on the X2 side in the X direction is set to the maximum thickness (= r0 - r2), it can extend to the spline fitting portion 70 on the X1 side in the X direction in a state of maximum thickness. In this case, the convex ridges that form the spline fitting portion 70 are arranged in multiple circumferential directions, so that they function as dams similar to the dam portion 89, and the oil reservoir can be maintained at a thickness t1 when the oil is at its maximum thickness.

In this way, according to this embodiment, the spline fitting portion 70 comes into axial contact with the oil pool of thickness t1, and can receive a stable supply of oil that forms the oil pool. In addition, the oil pool of thickness t1 can increase in thickness up to a maximum thickness according to the inner diameter r2 of the weir portion 89, and therefore oil can be steadily supplied to the spline fitting portion 70 that extends radially inward relative to the inner circumferential surface of the inner diameter r0 of the rotor shaft 314.

In particular, in this embodiment, as described above, the large diameter r1 (see Figures 5 and 6) of the female spline 71 of the spline fitting portion 70 is set to be larger than the inner diameter r2 of the dam portion 89. When the large diameter r1 of the female spline 71 of the spline fitting portion 70 is larger than the inner diameter r2 of the dam portion 89, the large diameter surface 711 of the female spline 71 of the spline fitting portion 70 is located radially outward from the innermost diameter position of the dam portion 89. This makes it easier for the oil level that accumulates on the inner peripheral surface of the rotor shaft 314 to exceed the large diameter surface 711 of the female spline 71 of the spline fitting portion 70 radially inward.

As a result, oil that accumulates on the inner peripheral surface of the rotor shaft 314 can permeate between the large diameter surface 711 of the female spline 71 of the spline fitting portion 70 and the large diameter surface 721 of the input shaft 31 (i.e., the mating surface between the large diameters). In addition, the female spline 71 and the male spline 72 themselves are lubricated by a small amount of oil that leaks into the spline fitting portion 70, which is a clearance fit (for example, oil that is pushed radially inward from within the gap as the gap between the tooth surfaces of the female spline 71 and the male spline 72 decreases, or oil that moves vertically downward as the rotation of the rotor 310 decreases).

In this way, according to this embodiment, the spline fitting portion 70 can be stably lubricated by the oil supplied from the X2 side of the rotor shaft 314 in the X direction (i.e., the oil supplied through the cover oil passage 80), thereby reducing the need to form a separate oil passage on the counter gear mechanism 4 side to lubricate the spline fitting portion 70. As a result, for example, as shown in FIG. 2, the input shaft 31 can be realized by a solid rotating shaft member, and in this case, the processing cost of the input shaft 31 can be reduced compared to when the input shaft 31 is realized by a hollow rotating shaft member (i.e., a rotating shaft member having a hollow interior that forms an oil passage). Note that the input shaft 31 can also be realized by a hollow rotating shaft member, and in this respect, the design freedom of the input shaft 31 can be increased.

Next, referring to Figures 7 and 8, as a modification of the above-described embodiment, a fitting portion between the rotor shaft 314 and the input shaft 31 that can be realized instead of the above-described spline fitting portion 70 will be described. In the following, components that may be similar to those in the above-described embodiment may be given the same reference numerals and descriptions thereof may be omitted.

Fig. 7 is a cross-sectional view showing a fitting portion 70A according to a first modified example, and is a cross-sectional view of a range corresponding to Fig. 5. Fig. 7A is an enlarged view of a portion Q4 in Fig. 7.
The fitting portion 70A according to the first modification includes a spline fitting portion 701 and a non-spline fitting portion 702, and the non-spline fitting portion 702 is set on the X1 side of the spline fitting portion 701 in the X-direction. Unlike the above-described spline fitting portion 70, the spline fitting portion 701 may be in the form of, for example, tooth surface fitting rather than in the form of large diameter fitting. The non-spline fitting portion 702 may be a fitting portion that does not involve meshing of convex ridge portions with each other (a fitting portion by clearance fitting).

In this modified example, the large diameter r3 of the female spline 71A of the rotor shaft 314A forming the spline fitting portion 701 is set to be larger than the inner diameter r2 of the dam portion 89. As a result, as in the above-mentioned embodiment, oil that accumulates on the inner peripheral surface of the rotor shaft 314 can be permeated between the large diameter surface 711A of the female spline 71A of the spline fitting portion 701 and the large diameter surface 721A (see FIG. 7A) of the male spline 72A of the input shaft 31A. In addition, the oil leaking into the gap between the female spline 71A in the spline fitting portion 701 and the male spline 72A of the input shaft 31A also realizes lubrication of the female spline 71A and the male spline 72A themselves. In addition, the oil leaking out to the X-direction X1 side through the gap of the spline fitting portion 701 also realizes lubrication of the non-spline fitting portion 702.

In this modified example, as shown in FIG. 7A, if the large diameter r3' (= the outer diameter of the large diameter surface 721A) of the male spline 72A of the input shaft 31A is significantly smaller than the large diameter r3 of the female spline 71A of the rotor shaft 314A, the large diameter r3' of the male spline 72A may be set to be larger than the inner diameter r2 of the dam portion 89. In this case, the above-mentioned effect can still be obtained.

Figure 8 is a cross-sectional view showing the spline fitting portion 70B according to the second modified example, and is a cross-sectional view of the range corresponding to Figure 5.

The spline fitting portion 70B according to the second modified example is realized by the rotor shaft 314B and the input shaft 31B, which are rotatably supported by two bearings 241A, 241B. Specifically, in the above-mentioned embodiment, the rotor shaft 314 and the input shaft 31 are supported by a common bearing 241 at the end related to the spline fitting portion 70, whereas in this modified example, the rotor shaft 314B and the input shaft 31B are supported by two bearings 241A, 241B, respectively, at the end related to the spline fitting portion 70B.

In this modified example, the larger diameter r4 of the female spline 71B (and the larger diameter of the male spline of the input shaft 31B) that forms the spline fitting portion 70B is set to be larger than the inner diameter r2 of the dam portion 89. This achieves the same effect as the above-mentioned embodiment.

Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or a combination of multiple components of the above-mentioned embodiments. Furthermore, among the effects of each embodiment, the effects related to the dependent claims are additional effects that are distinguished from the superordinate concept (independent claim).

For example, in the embodiment described above, the first oil passage 81 and the second oil passage 82 are formed by the cover member 252, but at least one of the first oil passage 81 and the second oil passage 82 may be formed by a tubular member separate from the cover member 252. For example, the first oil passage 81 may be realized by a hollow tubular member separate from the cover member 252. In this case, the second oil passage 82 may be realized by forming a radial hole in the hollow tubular member. Also, the second oil passage 82 may be omitted.

1: rotating electric machine, 7: power transmission mechanism, 31, 31A, 31B: input shaft (rotating shaft member), 320: stator, 310: rotor, 314: rotor shaft, 314A: hollow interior, 252: cover member (oil passage forming member), 71: female spline, 72, 72A: male spline, 721, 721A: large diameter surface, 89: dam section

Claims (5)

A stator;
a rotor having a hollow rotor shaft;
an oil passage forming member that forms an oil passage for supplying oil to a hollow interior of the rotor shaft,
the rotor shaft has, on an inner peripheral surface thereof, a dam portion that protrudes radially inward over the entire circumferential direction, and a female spline that meshes with a male spline of a rotating shaft member for transmitting rotational torque,
the oil passage supplies oil between the dam portion and the female spline in the axial direction,
an inner diameter of the dam portion is smaller than a major diameter of the female spline of the rotor shaft;
The rotating electric machine, wherein oil accumulated between the dam portion and the female spline comes into contact with the female spline . the oil passage forming member extends from an axial opening of the rotor shaft into a hollow interior of the rotor shaft on an axial side opposite to a side on which the female spline is formed,
The rotating electric machine according to claim 1 , wherein the dam portion is provided at a position overlapping the oil passage forming member when viewed in a radial direction of the rotor shaft. The rotating electric machine according to claim 1 or 2, wherein the rotor shaft has an oil hole passing through in the radial direction in the section between the female spline and the dam portion in the axial direction. The rotating electric machine according to claim 3, wherein the rotor shaft has an inner diameter larger than the inner diameter of the dam portion over the entire length of the section between the female spline and the oil hole in the axial direction. A rotating electric machine according to any one of claims 1 to 4,
a power transmission mechanism including the rotating shaft member fitted to the rotor shaft, the power transmission mechanism transmitting power based on a rotational torque generated by the rotating electric machine to wheels via the rotating shaft member,
A vehicle drive device, wherein the rotating shaft member is solid.