Rotary electric machine and vehicle drive device

Abstract

To suppress bubbling of oil in a case of a rotary electric machine.SOLUTION: An inner rotor type rotary electric machine 1 includes a limit section 6 which is disposed fixed to a case 9 in a scattering path of oil which is scattered from a rotor 12 to the outer side R2 in a radial direction R by a centrifugal force and limits movement of the oil in the radial direction R between a stator coil end part 13e protruding outward in an axial direction L relative to a stator core 11a and the rotor 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rotating electric machine and a vehicle drive device. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2021-148140 discloses an example of a vehicle drive system equipped with a rotating electric machine as a driving force source for wheels. This vehicle drive system also includes a gear mechanism that transmits power between the rotating electric machine and the wheels, and the rotating electric machine and gear mechanism are housed in a case. The case also contains oil for lubricating and cooling bearings that support the rotating members of the rotating electric machine and gear mechanism, the gear meshing portions, and the coils of the rotating electric machine. Vehicles equipped with a vehicle drive system not only travel straight on flat ground, but also travel on slopes and around curves. In this case, the area in which oil is stored within the case changes depending on whether the vehicle drive system tilts vertically along with the vehicle or whether acceleration is applied to the vehicle drive system. If oil becomes unevenly distributed within the case, it may not be possible to properly supply oil to areas requiring lubrication and cooling. Therefore, the above-mentioned document proposes a configuration that allows oil to be properly supplied to the rotating electric machine and gear mechanism even when the vehicle is positioned on a slope or traveling around a curve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-148140 Summary of the Invention [Problem to be solved by the invention]

[0004] When the oil level in a vehicle drive system is tilted and the oil in the case becomes uneven, the oil decreases on one side of the tilt, while the other side becomes excessively abundant. Because the case contains rotating components, the oil on the side where the oil level has increased is agitated more than necessary by the rotating components, making the oil more likely to foam. Even non-rotating components, such as the stator coil of a rotating electrical machine, can cause oil to foam when splashed through gaps between conductors. Foaming oil can reduce the oil's fluidity, reducing the amount of oil supplied to areas requiring lubrication or cooling, or the foamy oil can spread and reach areas where it should not.

[0005] In view of the above background, it is desirable to minimize foaming of oil inside the case. [Means for solving the problem]

[0006] In view of the above, a rotating electric machine is a rotating electric machine comprising a stator, a rotor, and a case that houses the stator and the rotor, the stator comprising a stator core and a stator coil wound around the stator core, the rotor being arranged radially inward relative to the stator in a direction perpendicular to the rotational axis of the rotor, the stator coil having a stator coil end portion that protrudes outward in the axial direction, which is a direction parallel to the rotational axis of the rotor, relative to the stator core, and a limiting portion that is fixed to the case and is arranged in a scattering path of oil that is scattered radially outward from the rotor due to centrifugal force, and that limits the movement of oil in the radial direction between the stator coil end portion and the rotor.

[0007] This configuration minimizes the amount of oil that is scattered radially outward from the rotor due to centrifugal force and reaches the stator coil end. This reduces the likelihood of oil foaming, which occurs when the scattered oil collides with the conductors at the stator coil end and passes through the gaps between the conductors. In other words, this configuration minimizes oil foaming within the case.

[0008] Further features and advantages of the rotating electric machine and the vehicle drive device including the rotating electric machine will become apparent from the following description of exemplary and non-limiting embodiments which will be described with reference to the drawings. [Brief explanation of the drawings]

[0009] [Figure 1] Cross-sectional view of a vehicle drive device equipped with a rotating electric machine [Figure 2] Skeleton diagram of a vehicle drive system equipped with a rotating electric machine [Figure 3] FIG. 10 is a diagram showing an example of an oil level in the rotating electrical machine housing chamber in a normal position; [Figure 4] FIG. 10 is a diagram showing an example of an oil level in the rotating electrical machine housing chamber in an inclined position. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of a rotating electric machine and a vehicle drive device including the rotating electric machine will be described with reference to the drawings. In the following description, the term "driving connection" refers to a state in which two rotating elements are connected to each other so as to be able to transmit driving force, and includes a state in which the two rotating elements are connected to each other so as to rotate integrally, or a state in which the two rotating elements are connected to each other so as to be able to transmit driving force via one or more transmission members. Such transmission members include various members that transmit rotation at the same speed or at different speeds, such as shafts, gear mechanisms, belts, and chains. Note that transmission members may also include engagement devices that selectively transmit rotation and driving force, such as friction engagement devices and meshing engagement devices. However, when the term "driving connection" is used to refer to each rotating element of a planetary gear mechanism, it refers to a state in which multiple rotating elements in the planetary gear mechanism are connected to each other without any other rotating elements intervening.

[0011] Furthermore, with regard to the arrangement of two elements, "overlapping when viewed in a specific direction" means that when an imaginary line parallel to the line of sight is moved in each direction perpendicular to the imaginary line, there is at least a part of an area where the imaginary line intersects with both of the two elements. Furthermore, with regard to the arrangement of two elements, "arrangement areas in a specific direction overlap" means that the arrangement area of ​​one element in a specific direction contains at least a part of the arrangement area of ​​the other element in a specific direction.

[0012] FIG. 1 is a cross-sectional view of a vehicle drive system 100 including a rotating electric machine 1 as a driving force source for wheels W, and FIG. 2 is a skeleton diagram of the vehicle drive system 100. The vehicle drive system 100 includes the rotating electric machine 1, output members (such as a differential input gear 41, a differential case 40, and a differential side gear 44, which will be described later) drivingly connected to the wheels W, and a power transmission mechanism 5 that transmits driving force between the rotating electric machine 1 and the output members. The rotating electric machine 1, the output members, and the power transmission mechanism 5 are housed in a case 9. The power transmission mechanism 5 may include an input shaft 2, a planetary gear mechanism 3 that functions as a reducer, and a differential gear mechanism 4 that distributes driving force transmitted from the rotating electric machine 1 via the planetary gear mechanism 3 to a pair of wheels W. The pair of differential side gears 44 that are output gears of the differential gear mechanism 4, the differential case 40 that houses the differential side gears 44, and the differential input gear 41 that is an input gear to the differential gear mechanism 4 are rotating members that correspond to the output members. The drive shafts (first drive shaft DS1, second drive shaft DS2) connected to the differential side gear 44 and the connecting shaft J can also be considered as output members.

[0013] As will be described in detail later, the rotating electric machine 1, the input shaft 2, and the planetary gear mechanism 3 are disposed on a first axis X1, and the differential gear mechanism 4 and the output member are disposed on a second axis X2. The first axis X1 and the second axis X2 are parallel to each other. In the following description, a direction parallel to the first axis X1 and the second axis X2 is referred to as the "axial direction L" of the vehicle drive device 100. One side of the axial direction L is referred to as the "axial first side L1," and the other side of the axial direction L is referred to as the "axial second side L2." The direction in which the rotating members revolve around their respective rotation axes is referred to as the "circumferential direction." The direction perpendicular to each of the first axis X1 and the second axis X2 is referred to as the "radial direction R" based on each axis. The side closer to the axis in the radial direction R is referred to as the "radial inner side R1," and the side farther from the axis is referred to as the "radial outer side R2." In addition, when it is not necessary to distinguish which axis is used as the reference, or when it is clear which axis is used as the reference, it may be simply referred to as the "radial direction R."

[0014] Furthermore, when the vehicle drive device 100 is mounted on a vehicle positioned on a horizontal plane, the direction along the vertical direction V (see FIGS. 3 and 4) is defined as the up-down direction Z, and the upper side along the up-down direction Z is referred to as the up-down direction upper side Z1, and the lower side along the up-down direction Z is referred to as the up-down direction lower side Z2. Furthermore, regardless of the posture of the vehicle drive device 100, the upper side along the vertical direction V based on the horizontal plane is referred to as the up-down direction upper side V1, and the lower side along the vertical direction V2. The radial direction R and the up-down direction Z of the vehicle drive device 100 coincide (see FIGS. 1 and 3). Furthermore, when the axial direction L is aligned horizontally, the up-down direction Z and the vertical direction V coincide (see FIG. 3).

[0015] In this embodiment, the case 9 includes a case main body 91, a first cover 92 joined to the case main body 91 from a first axial side L1, and a second cover 93 joined to the case main body 91 from a second axial side L2. The space surrounded by the case main body 91, the first cover 92, and the second cover 93 defines accommodation spaces (first accommodation chamber E1, second accommodation chamber E2) for accommodating the rotating electric machine 1 and the power transmission mechanism 5. The case main body 91 has a peripheral wall portion having a recessed portion (recess) recessed radially inward R1, and the case 9 further includes a third cover 94 that closes the recess. The space surrounded by the peripheral wall portion of the case main body 91 and the third cover 94 defines an accommodation space (third accommodation chamber E3) for accommodating the inverter device 20 that drives and controls the rotating electric machine 1.

[0016] The case body 91 is formed in a cylindrical shape with an opening on a first axial side L1 and a second axial side L2. The case body 91 also includes a support wall 91c that divides the internal space of the cylindrical case body 91 into the first axial side L1 and the second axial side L2. A first housing chamber E1 is formed in a space surrounded by the peripheral wall of the case body 91, the support wall 91c, and the first cover 92, and the first housing chamber E1 mainly houses the rotating electric machine 1. A second housing chamber E2 is formed in a space surrounded by the peripheral wall of the case body 91, the support wall 91c, and the second cover 93, and the second housing chamber E2 mainly houses the power transmission mechanism 5.

[0017] The rotating electric machine 1 includes a stator 11, a rotor 12, and a case 9 that houses the stator 11 and the rotor 12. In this embodiment, the rotating electric machine 1 is an inner rotor type rotating electric machine in which the rotor 12 is disposed on the radially inner side R1 of the stator 11. The stator 11 includes a stator core 11a fixed to the case 9 and a stator coil 13 wound around the stator core 11a. The stator coil 13 includes a stator coil end portion 13e that protrudes outward in the axial direction L from the stator core 11a. In this embodiment, a pair of stator coil end portions 13e are provided that protrude outward on both sides in the axial direction L from the stator core 11a. However, a single stator coil end portion 13e may be provided that protrudes only on one side in the axial direction L from the stator core 11a. The rotor 12 includes a rotor core 12a rotatably supported relative to the case 9, and a rotor shaft 10 disposed radially inward R1 of the rotor core 12a and connected to the rotor core 12a so as to rotate integrally with the rotor core 12a. Although not shown, the rotor core 12a is provided with a permanent magnet.

[0018] The rotating electric machine 1 has a function as an electric motor that receives a supply of electric power to generate power, and a function as a generator that receives a supply of power to generate power. Specifically, the rotating electric machine 1 is electrically connected to a DC power source (not shown), such as a battery or a capacitor. The rotating electric machine 1 generates driving force by running using the electric power stored in the DC power source. The rotating electric machine 1 also generates power using the driving force transmitted from the wheels W to charge the DC power source.

[0019] The rotor shaft 10 is formed in a hollow cylindrical shape, and an in-shaft space 10E on the radially inner side R1 forms an oil passage through which oil flows. The rotor shaft 10 also has protrusions 10a protruding from the rotor core 12a to both sides in the axial direction L. The protrusion 10a on the first axial side L1 is rotatably supported in the radial direction R relative to the case 9 via a first rotor bearing B11 fixed to the case 9 (first cover 92). The first rotor bearing B11 is fixed to the case 9 in a state where movement toward the first axial side L1 is restricted. The protrusion 10a on the second axial side L2 is rotatably supported in the radial direction R relative to the case 9 via a second rotor bearing B12 fixed to the case 9 (support wall portion 91c). The second rotor bearing B12 is fixed to the case 9 in a state where movement toward the second axial side L2 is restricted.

[0020] The input shaft 2 is connected by spline engagement to the radially inner side R1 of the protruding portion 10a on the second axial side L2 of the rotor shaft 10. That is, the rotor shaft 10 and the input shaft 2 are connected so as to rotate integrally. The protruding portion 10a on the second axial side L2 of the rotor shaft 10 is rotatably supported relative to the case 9 via the second rotor bearing B12. Therefore, it can be said that the input shaft 2 is rotatably supported relative to the case 9 via the second rotor bearing B12 on the first axial side L1. Furthermore, the input shaft 2 is rotatably supported from the second axial side L2 via the input bearing B2. The input bearing B2 is a thrust bearing.

[0021] Furthermore, a sun gear SG of the planetary gear mechanism 3, which corresponds to the input gear in the power transmission mechanism 5, is formed integrally with the input shaft 2. In the present embodiment, an example is shown in which the sun gear SG is formed integrally with the input shaft 2 using the same member, but the input shaft 2 and the sun gear SG may also be formed using separate members and integrated by welding, fastening, or the like.

[0022] The planetary gear mechanism 3, which functions as a reducer that reduces the rotation of the rotor 12 and transmits it to the differential gear mechanism 4, is equipped with a sun gear SG, a carrier CR, and a ring gear RG as rotating elements. The carrier CR rotatably supports a first pinion gear PG1 and a second pinion gear PG2 that rotate integrally with each other. The first pinion gear PG1 meshes with the sun gear SG. The second pinion gear PG2 meshes with the ring gear RG. In addition, a reduction output gear 31 is connected to the carrier CR so as to rotate integrally with the carrier CR.

[0023] The reduction output gear 31 meshes with a differential input gear 41, which is an input gear to the differential gear mechanism 4. The differential gear mechanism 4 includes a differential case 40, a plurality of differential pinion gears 42, and a pair of differential side gears 44. The differential case 40 is rotatably supported on the support wall portion 91c via a first differential bearing B41 on the first axial side L1, and is rotatably supported on the second cover 93 via a second differential bearing B42 on the second axial side L2.

[0024] The differential pinion gears 42 and the differential side gears 44 are bevel gears, and the differential gear mechanism 4 of this embodiment is a bevel gear type differential gear mechanism. A differential case 40 has a differential pinion shaft 43 fixed thereto, and the differential pinion gears 42 are supported by the differential case 40 so as to be rotatable about the differential pinion shafts 43 as rotation axes. A plurality of differential pinion shafts 43 are provided in a cross shape, for example, along the radial direction R of the second axis X2, and a plurality of differential pinion gears 42 are supported by the differential pinion gears 42. Each of the plurality of differential pinion gears 42 meshes with a corresponding one of the pair of differential side gears 44.

[0025] In this embodiment, the differential side gear 44 on the first axial side L1 is connected to rotate integrally with a first drive shaft DS1, which is drivingly connected to a wheel W on the first axial side L1, via a connecting shaft J extending along the axial direction L. The differential side gear 44 on the second axial side L2 is connected to rotate integrally with a second drive shaft DS2, which is drivingly connected to a wheel W on the second axial side L2.

[0026] The case 9 also contains oil for lubricating the bearings and gear meshing portions that support the rotating members of the rotating electric machine 1 and the power transmission mechanism 5, and for cooling the stator coil 13 of the rotating electric machine 1. This oil is stored in the lower part of the case 9 and is supplied to the parts to be lubricated or cooled by being sucked and discharged by an oil pump (not shown) or by being scooped up by rotating members such as the differential input gear 41. Figure 3 shows the oil level P of the oil stored in the first storage chamber E1 of the case 9 when the rotating members are stopped, i.e., in a static state.

[0027] Incidentally, a vehicle equipped with the vehicle drive device 100 not only travels straight on flat ground, but also travels on slopes and around curves. In this case, the vehicle drive device 100 may tilt with the vehicle relative to the vertical direction V, or acceleration may act on the vehicle drive device 100, causing the region in which oil is stored within the case 9 to change. That is, the position of the oil level P tilts as shown in FIG. 3 from a direction perpendicular to the up-down direction Z of the vehicle drive device 100 as shown in FIG. 4.

[0028] If the oil level P in the vehicle drive device 100 tilts and the oil in the case 9 becomes uneven, the oil decreases on one side of the tilt, while the oil becomes excessively abundant on the other side. As is clear from a comparison of FIGS. 3 and 4 , if the oil level P tilts as shown in FIG. 4 and the oil in the case 9 becomes uneven, the rotor 12, which is not normally immersed in oil, may become immersed in oil. Because the rotor 12 is a rotating member housed in the case 9, the oil is agitated more than necessary by the rotating member on the side where the oil increases, making the oil more likely to foam. For example, as shown in FIG. 4 , if the oil level P in the case 9 tilts toward the upper side Z1 (the ceiling side of the case 9) as it moves toward the first axial side L1, the oil is agitated by the rotor 12. The oil agitated by the rotor 12 passes through the gaps in the stator coil 13 at the stator coil end portion 13e, making the oil more likely to foam. This foaming can reduce the fluidity of the oil, reducing the amount of oil supplied to areas that require lubrication or cooling, or the foamy oil can spread and end up reaching areas where it should not.

[0029] Therefore, the rotating electric machine 1 of this embodiment is provided with a restriction unit 6 that restricts the movement of oil in the radial direction R between the stator coil end portion 13e and the rotor 12 in a scattering path of oil that is scattered radially outward R2 from the rotor 12 immersed in oil due to centrifugal force due to the uneven distribution of oil. The restriction unit 6 is disposed in a fixed state to the case 9. In this embodiment, the stator core 11a is provided with the stator coil end portion 13e on both sides in the axial direction L, and the restriction unit 6 is disposed on the radially inner side R1 of the stator coil end portion 13e on the first axial side L1. Note that the "scattering path" of oil that scatters from the rotor 12 toward the radially outward R2 corresponds to a path connecting the stator coil end portion 13e with a location on the rotor 12 where oil may adhere.

[0030] It is preferable to position the restriction portion 6 as close as possible to the inner peripheral surface of the stator coil end portion 13e in the radial direction R. If the distance in the radial direction R between the restriction portion 6 and the inner peripheral surface of the stator coil end portion 13e becomes long, the outer peripheral surface of the rotor 12 is more likely to be positioned radially outward R2 relative to the restriction portion 6, reducing the effect of restricting oil scattering from the rotor 12.

[0031] Furthermore, the present embodiment illustrates an example in which the limiting portion 6 is integrally formed with the case 9, specifically, an example in which the limiting portion 6 is formed so as to protrude from the first cover 92 toward the second axial side L2. However, the limiting portion 6 may be formed as a separate member from the case 9 and fixed to the case 9 by welding or fastening. Of course, the limiting portion 6 may be formed of a material (e.g., resin) different from the metal case 9 and fixed to the case 9 by adhesive, fastening, or the like. When the limiting portion 6 is made of metal, it is necessary to position the limiting portion 6 taking into consideration the insulation distance in the radial direction R between the stator coil end portion 13e and the limiting portion 6. When the limiting portion 6 is made of a non-conductive material such as resin, it is easier to position the limiting portion 6 on the radially outer side R2 regardless of the insulation distance, and it is easier to shorten the distance in the radial direction R between the stator coil end portion 13e and the limiting portion 6.

[0032] Furthermore, in the present embodiment, the restricting portion 6 is provided on the stator coil end portion 13e side of the first axial side L1, but the restricting portion 6 may be provided on both the first axial side L1 and the second axial side L2. That is, it is sufficient that the restricting portion 6 is disposed at least on the side of the stator coil end portion 13e of the pair of stator coil end portions 13e that protrudes toward the first axial side L1 with respect to the stator core 11a.

[0033] Furthermore, the restricting portion 6 of this embodiment is formed in a cylindrical shape continuously over the entire circumferential direction along the inner circumferential surface of the radially inner side R1 of the stator coil end portion 13e. This allows oil scattering from the rotor 12 to the stator coil end portion 13e to be appropriately restricted. However, the restricting portion 6 is not limited to being formed continuously over the entire circumferential direction as described above, and the restricting portion 6 may be formed discontinuously in the circumferential direction. In other words, the restricting portion 6 may be formed only in part of the circumferential direction. Even if the restricting portion 6 is continuous, it is not limited to being cylindrical, and the circumferential surface may have a shape inclined with respect to the axial direction L, such as a truncated cone shape.

[0034] The vehicle drive device 100 of this embodiment includes a breather 8 that communicates between the inside and outside of the case 9. As described above with reference to FIGS. 1 and 2, the rotating electric machine 1 is disposed on the first axial side L1 with respect to the power transmission mechanism 5. The breather 8 is disposed on the second axial side L2, opposite the first axial side L1, with respect to the stator core 11a. That is, the breather 8 is disposed between the rotating electric machine 1 and the power transmission mechanism 5 in the axial direction L. In this embodiment, the breather 8 is disposed between the support wall portion 91c and the rotating electric machine 1 (the stator coil end portion 13e) so as to communicate between the first housing chamber E1 and the outside of the case 9. However, since the first housing chamber E1 and the second housing chamber E2 are communicated with each other, the breather 8 may be disposed in the second housing chamber E2. That is, the breather 8 may be disposed in the region of the axial direction L where the power transmission mechanism 5 is disposed.

[0035] In this embodiment, the power transmission mechanism 5 is accommodated on the second axial side L2 of the case 9. Therefore, when the oil level P in the case 9 tilts toward the upper side Z1 in the vertical direction (toward the ceiling of the case 9) as it moves toward the second axial side L2, the oil moves toward the second housing chamber E2, and the oil level P in the first housing chamber E1 is positioned on the lower side Z2 in the vertical direction than the normal oil level P shown in Fig. 3. Therefore, it is considered that the rotor 12 is unlikely to stir the oil.

[0036] On the other hand, as illustrated in FIG. 4 , if the oil level P tilts toward the upper side Z1 in the vertical direction as it moves toward the first axial side L1, the oil that is agitated by the rotor 12 and scattered may pass through the gaps in the stator coil 13 at the stator coil end portion 13e, causing the oil to foam. The spread of the foamy oil may result in the oil reaching a location where it should not, such as the breather 8. For example, the oil that has spread due to the bubbles may pass through the gaps in the radial direction R between the stator core 11a and the rotor core 12a or the gaps in the radial direction R between the stator core 11a and the case 9, and move by capillary action from the first axial side L1 to the second axial side L2, eventually reaching the breather 8. In this case, there is a risk of oil spraying out of the case 9 through the breather 8. While it is conceivable to provide the breather 8 in a location where it will not be affected by bubbles, it may be difficult to secure an appropriate installation location for the breather 8 while simultaneously miniaturizing the vehicle drive system 100.

[0037] According to this embodiment, since oil foaming in the stator coil end portion 13e on the first axial side L1 can be reduced, even when the oil level P in the case 9 is tilted in this manner, the possibility of the foamed oil reaching the breather 8 can be reduced. In other words, the phenomenon of oil spurting out of the case 9 from the breather 8 can be made less likely to occur. This can also reduce obstacles to downsizing the vehicle drive device 100.

[0038] Furthermore, if the oil foams too much, air may be sucked in when the oil pump draws in the oil, which could result in a decrease in the oil discharge pressure and discharge volume. If the restriction section 6 can suppress oil foaming, it is easier to suppress such effects on the oil pump.

[0039] Incidentally, a large current of several amperes flows through the stator coil 13, generating a large amount of heat. Therefore, the stator coil end portion 13e is cooled by oil. In this embodiment, a radial oil passage 7 is formed along the radial direction R to connect an in-shaft space 10E formed on the radially inner side R1 of the cylindrical rotor shaft 10, which serves as an in-shaft oil passage, with the outer circumferential surface of the protruding portion 10a of the rotor shaft 10. Oil supplied to the in-shaft space 10E passes through the radial oil passage 7 due to centrifugal force generated by the rotation of the rotor shaft 10 and is sprayed toward the radially outer side R2 from a spray port 7a formed at the end of the radial oil passage 7 on the radially outer side R2. Because the protruding portion 10a of the rotor shaft 10 and the stator coil end portion 13e face each other in the radial direction R, the oil sprayed from the spray port 7a is supplied to the stator coil end portion 13e by centrifugal force and cools the stator coil 13.

[0040] If the restricting portion 6 is provided between the protruding portion 10a of the rotor shaft 10 and the stator coil end portion 13e, the movement of oil ejected from the ejection port 7a of the radial oil passage 7 may also be restricted. For this reason, in this embodiment, the restricting portion 6 is configured to form a gap 6a that allows the oil ejected from the ejection port 7a to pass in the radial direction R in a region that overlaps with the ejection port 7a as viewed in the radial direction along the radial direction R. As a result, when the oil level P is significantly tilted compared to normal, the amount of oil that is scattered from the rotor 12 toward the radially outer side R2 due to centrifugal force and reaches the stator coil end portion 13e can be kept small. Meanwhile, when the oil level P is normal or not significantly tilted compared to normal (for example, approximately 5 degrees), oil can be ejected from the rotor shaft 10 to the stator coil end portion 13e through the ejection port 7a to cool the stator coil 13.

[0041] In this embodiment, as described above, the restricting portion 6 is formed continuously over the entire circumference in the circumferential direction. The gap 6a of the restricting portion 6 is also formed over the entire circumference in the circumferential direction. Naturally, even if the restricting portion 6 is formed continuously over the entire circumference in the circumferential direction, this does not prevent the gap 6a from being formed discontinuously, i.e., intermittently in the circumferential direction.

[0042] Furthermore, in the present embodiment, the rotor shaft 10 penetrates the rotor core 12a in the axial direction L, and the rotor shaft 10 has protruding portions 10a on both sides of the rotor core 12a in the axial direction L. The configuration in which the radial oil passages 7 are formed in the pair of protruding portions 10a has been exemplified. However, the rotor shaft 10 may not penetrate the rotor core 12a, and may have protruding portion 10a only on the first axial side L1 of the rotor core 12a, and the input shaft 2 may be inserted into and connected to the radial inner side R1 of the rotor core 12a on the second axial side L2 of the rotor core 12a. In this case, the radial oil passages 7 formed in the protruding portions 10a are only on the first axial side L1. In this case, it is preferable that an in-shaft oil passage is formed on the radial inner side R1 of the input shaft 2, an oil passage is formed along the radial direction R so as to connect the in-shaft oil passage of the input shaft 2 with the outer peripheral surface of the input shaft 2, and cooling oil is supplied to the stator coil end portion 13e on the axial second side L2 through the oil passage.

[0043] Furthermore, in this embodiment, the vehicle drive device 100 has been described as having a two-shaft configuration in which rotating members are arranged on two shafts, the first shaft X1 and the second shaft X2. However, if an inner rotor type rotating electric machine 1 is provided, even in a vehicle drive device 100 having a single shaft configuration or a vehicle drive device 100 having three or more shafts, a phenomenon in which the rotor 12 stirs the oil due to the inclination of the oil level P and the stator coil end portion 13e promotes oil foaming may occur. Therefore, the configuration of the vehicle drive device 100 is not limited to the two-shaft configuration exemplified above.

[0044] For example, the vehicle drive device 100 may have a single-shaft configuration in which the rotating electric machine 1, the reducer of the planetary gear mechanism 3, and the differential gear mechanism 4 are arranged coaxially. Alternatively, the vehicle drive device 100 may have a three-shaft configuration in which the rotating electric machine 1, the reducer of the counter gear mechanism, and the differential gear mechanism 4 are arranged on separate, parallel axes. Note that, in the case where the vehicle drive device 100 is configured such that power is transmitted in the order of the rotating electric machine 1, the counter gear mechanism, and the differential gear mechanism 4, the vehicle drive device 100 may have a folded two-shaft configuration in which the rotating electric machine 1 and the differential gear mechanism 4 are arranged coaxially and the counter gear mechanism is arranged on a separate axis, and power is transmitted from the rotating electric machine 1 to the counter gear mechanism on the separate axis and then from the counter gear mechanism to the differential gear mechanism 4 arranged coaxially with the rotating electric machine 1. Furthermore, in common with all configurations, the differential gear mechanism 4 is not limited to being a bevel gear mechanism as exemplified above, and may be configured using a planetary gear mechanism.

[0045] Preferred embodiments of the rotating electric machine (1) and the vehicle drive device (100) described above will be briefly summarized below.

[0046] In one aspect, the rotating electric machine (1) includes a stator (11), a rotor (12), and a case (9) that houses the stator (11) and the rotor (12), the stator (11) includes a stator core (11a) and a stator coil (13) wound around the stator core (11a), and the rotor (12) is disposed on the inner side (R1) of the stator (11) in a radial direction (R) perpendicular to a rotation axis (X1) of the rotor (12), and the stator coil The oil (13) has a stator coil end portion (13e) that protrudes outward in the axial direction (L), which is a direction parallel to the rotation axis (X1) of the rotor (12), relative to the stator core (11a), and has a limiting portion (6) that is fixed to the case (9) and is arranged in a scattering path of oil that is scattered from the rotor (12) toward the outside (R2) in the radial direction (R) by centrifugal force, and limits the movement of oil in the radial direction (R) between the stator coil end portion (13e) and the rotor (12).

[0047] This configuration can reduce the amount of oil that is scattered from the rotor (12) toward the outer side (R2) in the radial direction (R) due to centrifugal force and reaches the stator coil end portion (13e). Therefore, the scattered oil collides with the conductors at the stator coil end portion (13e) and passes through the gaps between the conductors, which reduces the likelihood of oil foaming. In other words, this configuration can reduce the amount of oil foaming inside the case (9).

[0048] The rotating electric machine (1) preferably includes a rotor (12) including a rotor core (12a) and a rotor shaft (10) connected to the rotor core (12a) so as to rotate integrally with the rotor core (12a) and having a protrusion (10a) protruding from the rotor core (12a) in the axial direction (L), the protrusion (10a) having an injection port (7a) for injecting oil toward the stator coil end portion (13e) from an inner side (R1) in the radial direction (R) relative to the stator coil end portion (13e), and the restriction portion (6) is configured to form a gap (6a) for allowing the oil injected from the injection port (7a) to pass in the radial direction (R) in a region overlapping with the injection port (7a) when viewed in the radial direction along the radial direction (R).

[0049] According to this configuration, the amount of oil that is scattered from the rotor (12) toward the outer side (R2) in the radial direction (R) by centrifugal force and reaches the stator coil end portion (13e) can be reduced, and the oil can be injected from the rotor shaft (10) through the injection port (7a) to the stator coil end portion (13e). Therefore, the amount of oil foaming in the case (9) can be reduced, and the stator coil end portion (13e) can be appropriately cooled by the oil.

[0050] In addition, a vehicle drive device (100) including a rotating electric machine (1), an output member (41, 40, 44, DS1, DS2, J) drivingly connected to a wheel (W), a power transmission mechanism (5) that transmits driving force between the rotating electric machine (1) and the output member (41, 40, 44, DS1, DS2, J), and a breather (8) that communicates the inside and outside of the case (9) is configured such that the case (9) further accommodates the power transmission mechanism (5), and the rotating electric machine (1) is positioned on one side of the axial direction (L) relative to the power transmission mechanism (5) in an axial first side (L1). a pair of stator coil end portions (13e) are provided protruding outward in both axial directions (L) relative to the stator core (11a), the limiting portion (6) is arranged at least on the side of the stator coil end portion (13e) of the pair of stator coil end portions (13e) protruding toward the first axial side (L1) relative to the stator core (11a), and the breather (8) is arranged on the second axial side (L2) opposite the first axial side (L1) relative to the stator core (11a).

[0051] If the oil level (P) in the case (9) tilts toward the ceiling of the case (9) as it moves toward the first axial side (L1), the rotor (12) is more likely to stir the oil, which in turn increases the likelihood of oil foaming at the stator coil end portion (13e) on the first axial side (L1). Even if the breather (8) is located on the second axial side (L2) of the stator core (11a), the generated bubbles may reach the breather (8). However, this configuration minimizes oil foaming at the stator coil end portion (13e) on the first axial side (L1). Therefore, even if the oil level (P) in the case (9) tilts, oil foaming at the stator coil end portion (13e) on the first axial side (L1) is minimized, reducing the likelihood of foamed oil reaching the breather (8). Therefore, this configuration reduces the likelihood of oil spraying out of the case (9) from the breather (8). [Explanation of symbols]

[0052] 1: rotating electric machine, 5: power transmission mechanism, 6: restriction portion, 6a: gap, 7a: outlet, 8: breather, 9: case, 10: rotor shaft, 10a: protrusion, 11: stator, 11a: stator core, 12: rotor, 12a: rotor core, 13: stator coil, 13e: stator coil end portion, 40: differential case (output member), 41: differential input gear (output member), 44: differential side gear (output member), 100: vehicle drive device, DS1: first drive shaft (output member), DS2: second drive shaft (output member), J: connecting shaft (output member), L: axial direction, L1: first axial side, L2: second axial side, R: radial direction, R1: radially inner side (radially inner side), R2: radially outer side (radially outer side), W: wheel, X1: first shaft (rotational axis of rotor)

Claims

1. a stator, a rotor, and a case that houses the stator and the rotor; a rotating electric machine, wherein the stator includes a stator core and a stator coil wound around the stator core, and the rotor is disposed radially inward relative to the stator in a direction perpendicular to a rotation axis of the rotor, the stator coil includes a stator coil end portion that protrudes outward in an axial direction, which is a direction parallel to a rotation axis of the rotor, relative to the stator core; a limiting portion that is fixed to the case and disposed in a scattering path of oil that is scattered radially outward from the rotor due to centrifugal force, and that limits the movement of oil in the radial direction between the stator coil end portion and the rotor.

2. the rotor includes a rotor core, and a rotor shaft connected to the rotor core so as to rotate integrally with the rotor core and having a protruding portion protruding from the rotor core in the axial direction, the protruding portion is provided with an injection port that injects oil toward the stator coil end portion from the radially inner side of the stator coil end portion, 2. The rotating electric machine according to claim 1, wherein the restricting portion is configured to form a gap in a region overlapping with the injection port when viewed in the radial direction along the radial direction, through which oil injected from the injection port passes in the radial direction.

3. a rotating electric machine according to claim 1 or 2; an output member drivingly connected to the wheels; a power transmission mechanism that transmits a driving force between the rotating electric machine and the output member; a breather that connects the inside and outside of the case, the case further houses the power transmission mechanism; the rotating electric machine is disposed on a first axial side, which is one side in the axial direction, with respect to the power transmission mechanism; The stator coil end portions are provided in pairs so as to protrude outwardly from the stator core in the axial direction, the limiting portion is disposed at least on the side of the stator coil end portion of the pair of stator coil end portions that protrudes toward the first axial direction relative to the stator core, The breather is disposed on a second axial side of the stator core opposite to the first axial side.

Images