Driving device for vehicle

Abstract

To achieve a structure in which oil can be properly supplied to a lubrication object place arranged at each shaft, in a driving device for vehicle which includes three rotation shafts in parallel with each other.SOLUTION: A first shaft center A1 which is a rotation shaft center of an input member is arranged closer to an upper side V1 than a second shaft center A2 which is a rotation shaft center of a counter gear mechanism and a third shaft center A3 which is a rotation shaft center of an output member. A case 9 includes: a first oil passage 71 for supplying oil from an oil supply source to a first bearing for rotatably supporting the input member; a second oil passage 72 branched from the first oil passage 71 and supplying the oil to a second bearing for rotatably supporting the counter gear mechanism; and a third oil passage 73 branched from the first oil passage 71, and supplying the oil to a third bearing for rotatably supporting the output member.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Japanese Patent Application Laid-Open Publication No. 2022-44049 discloses a vehicle drive device (100) having a three-axis configuration in which a rotating electric machine (1), a reduction gear mechanism (4), and an output member (6) are arranged on different axes (reference symbols in parentheses in the Background Art refer to those in the referenced documents). In this vehicle drive device (100), when the vehicle is mounted on a vehicle (200), the axis on which the reduction gear mechanism (4) is arranged (third axis (C3)) and the axis on which the output member (6) is arranged (second axis (C2)) are arranged at approximately the same height in the vertical direction (V). Furthermore, the axis on which the rotating electric machine (1) is arranged (first axis (C1)) is arranged above the axis (C3) on which the reduction gear mechanism (4) is arranged in the vertical direction (V) so as to be aligned with the axis (C3) in the vertical direction (V). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-44049 Summary of the Invention [Problem to be solved by the invention]

[0004] These shafts rotatably support rotating members via bearings or the like. Therefore, in many cases, the bearings or the like are lubricated by oil contained in the case of the vehicle drive system. In many cases, the oil is supplied from above the case, lubricates multiple lubrication points, and then flows downward through the case to an oil reservoir below the case. It is preferable that the oil path be configured so that an appropriate amount of oil is supplied to each lubrication point while appropriately recovering frictional heat and the like through heat exchange, thereby preventing overheating of the lubrication points.

[0005] In view of the above background, it is desirable to realize a structure in a vehicle drive device having three mutually parallel rotating shafts that can appropriately supply oil to the parts to be lubricated that are arranged on each shaft. [Means for solving the problem]

[0006] In view of the above, a vehicle drive device includes a rotating electric machine having a rotor, an input member connected to the rotor so as to rotate integrally with the rotor, an output member drivingly connected to a wheel, a speed reduction mechanism that reduces the rotation of the input member and transmits the reduced rotation to the output member, and a case that accommodates the rotating electric machine, the input member, and the speed reduction mechanism, wherein the speed reduction mechanism includes a counter gear mechanism including an input gear connected to the input member so as to rotate integrally with the input member, a first counter gear meshing with the input gear, and a second counter gear connected to rotate integrally with the first counter gear, and a second counter gear meshing with the second counter gear and rotating integrally with the output member. the input member is rotatably supported relative to the case via a first bearing, the counter gear mechanism is rotatably supported relative to the case via a second bearing, the output member is rotatably supported relative to the case via a third bearing, a first axis which is a rotation axis of the input member is disposed above a second axis which is a rotation axis of the counter gear mechanism and a third axis which is a rotation axis of the output member, and the case comprises: a first oil passage which supplies oil from an oil supply source to the first bearing, a second oil passage which branches off from the first oil passage and supplies oil to the second bearing, and a third oil passage which branches off from the first oil passage and supplies oil to the third bearing.

[0007] According to this configuration, the rotation of the input member is reduced by the reduction mechanism and transmitted to the output member, so the rotational speed of the input member is higher than the rotational speed of the counter gear mechanism and the rotational speed of the output member. Therefore, the load on the first bearing supporting the input member is higher than the load on the second bearing supporting the counter gear mechanism and the load on the third bearing supporting the output member. According to this configuration, oil from the supply source is supplied to the first bearing through the first oil passage, and the oil is distributed to the second and third bearings through the second and third oil passages branching from the first oil passage. This allows a large amount of oil to be supplied to the first bearing, which is subjected to the highest load, while the remaining oil after supplying to the first bearing can be used to lubricate the second and third bearings. In other words, the amount of oil supplied from the supply unit can be kept low while an appropriate amount of oil corresponding to the load can be supplied to each bearing. Thus, according to this configuration, a vehicle drive system having three parallel rotating shafts can be realized that can appropriately supply oil to the lubrication target locations located on each shaft.

[0008] Further features and advantages of the vehicle drive device will become apparent from the following description of exemplary, non-limiting embodiments which are given with reference to the drawings. [Brief explanation of the drawings]

[0009] [Figure 1] Schematic exploded perspective view of a vehicle drive device [Figure 2] Skeleton diagram of a vehicle drive system [Figure 3] 1 is a side view of a vehicle drive device from a first axial side; [Figure 4] 1 is a side view (front view) of a vehicle drive device from a first side in a front-rear direction; [Figure 5] FIG. 1 is an enlarged side view of a vehicle drive device from a first axial side with a first cover open; DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of a vehicle drive device will be described with reference to the drawings. Fig. 1 is a schematic exploded perspective view of a vehicle drive device 10. Note that some components, such as a portion of a cover member that configures a case 9, are omitted from this exploded perspective view. Fig. 2 is a skeleton diagram of the vehicle drive device 10.

[0011] In the following description, the term "driving connection" refers to a state in which two rotating elements are connected so as to be able to transmit a driving force, and includes a state in which the two rotating elements are connected so as to rotate integrally, or a state in which the two rotating elements are connected so as to be able to transmit a driving force via one or more transmission members. Such transmission members include various members that transmit rotation at the same speed or at variable 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 passing through other rotating elements.

[0012] As shown in FIGS. 1 and 2 , a vehicle drive device 10 includes a rotating electric machine 1, an input member 2, a counter gear mechanism 3, a differential gear mechanism 4, and a case 9. The case 9 houses the rotating electric machine 1, the input member 2, the counter gear mechanism 3, and the differential gear mechanism 4. The input member 2 is connected to the rotor 11 of the rotating electric machine 1 so as to rotate integrally with the rotor 11. In this embodiment, the input member 2 is spline-coupled to a rotor shaft 20 connected to the rotor 11, and rotates integrally with the rotor 11 and the rotor shaft 20. Note that the rotor shaft 20 and the input member 2 may be the same member. The differential gear mechanism 4 distributes the driving force transmitted from the rotating electric machine 1 to a pair of output members drivingly connected to a pair of wheels W. Although details will be described later, in this embodiment, a differential case 42 of the differential gear mechanism 4 corresponds to the output members.

[0013] The vehicle drive device 10 includes a speed reduction mechanism that reduces the rotation of the input member 2 and transmits the reduced rotation to an output member (differential case 42). As shown in FIG. 2 , in this embodiment, the speed reduction mechanism includes an input gear 21, a counter gear mechanism 3, and a differential input gear 41 (output gear). The input gear 21 is connected to the input member 2 so as to rotate integrally with the input member 2. The input gear 21 may be formed integrally with the input member 2, which is a shaft member, from the same member, or may be formed from a member separate from the input member 2 and integrated with the input member 2 by welding or the like. Similarly, a first counter gear 31 and a second counter gear 32, which will be described later, may be formed from the same member as the shaft member (counter shaft 30) or from separate members, and the differential input gear 41 may be formed from the same member as the differential case 42 or from separate members.

[0014] The counter gear mechanism 3 includes a first counter gear 31 and a second counter gear 32. The first counter gear 31 and the second counter gear 32 are both connected to the counter shaft 30 so as to rotate integrally. The first counter gear 31 meshes with the input gear 21, and the second counter gear 32 meshes with a differential input gear 41. The differential input gear 41 is connected to a differential case 42 (output member) so as to rotate integrally with the differential case 42.

[0015] As shown in FIG. 2, the rotating electric machine 1 (rotor 11) and the input member 2 are disposed on a first axis A1 (first axis). The counter gear mechanism 3 is disposed on a second axis A2 (second axis) that is parallel to the first axis A1. The differential gear mechanism 4 including the differential case 42 (output member) is disposed on a third axis A3 (third axis) that is parallel to the first axis A1 and the second axis A2. In this embodiment, as shown in FIG. 1, the first axis A1 is disposed on a side V1 above the second axis A2 and the third axis A3. Note that, although the present embodiment illustrates an example in which the second axis A2 is disposed on the side V1 above the third axis A3, the second axis A2 and the third axis A3 may be disposed at the same position in the vertical direction V, or the third axis A3 may be disposed on the side V1 above the second axis A2.

[0016] In the following description, the direction parallel to the first axis A1, the second axis A2, and the third axis A3 is referred to as the "axial direction L" of the vehicle drive device 10. 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 C" (see FIG. 1). The directions perpendicular to the first axis A1, the second axis A2, and the third axis A3 are referred to as the "radial direction R" based on each axis (see FIG. 1). The side of the radial direction R closer to the axis 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." Note that 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, the term "radial direction R" may be used simply.

[0017] Furthermore, in a state in which the vehicle drive device 10 is mounted on a vehicle, the direction along the vertical direction is referred to as the up-down direction V, and the upper side along the up-down direction V is referred to as the upper side V1, and the lower side along the up-down direction V is referred to as the lower side V2. In this embodiment, in a state in which the vehicle is mounted, the axial direction L is along the horizontal direction, and the axial direction L and the up-down direction V are orthogonal. In this state, the direction orthogonal to the axial direction L and the up-down direction V is referred to as the fore-aft direction X, and one side of the fore-aft direction X is referred to as the "first fore-aft side X1," and the other side of the fore-aft direction X is referred to as the "second fore-aft side X2."

[0018] In this embodiment, the rotating electric machine 1 is exemplified as an electrically excited synchronous motor (EESM) having a stator 15 on which multiple-phase (N-phase, e.g., three-phase, where N is an arbitrary natural number) stator coils 17 are arranged, and a wound-field rotor 11. A wound-field synchronous rotating electric machine has a rotor structure equipped with an electromagnet that uses a field winding (rotor coil 13) instead of a permanent magnet as a field source. The field magnetic flux generated by the electromagnet can be adjusted by a field current supplied to the rotor winding 13 from an excitation circuit (both of which are included in an electric circuit unit EU, described later) controlled by a control device via a wireless power supply 18 and a rectifier circuit 19 (see FIG. 2). The excitation circuit adjusts a DC voltage supplied from a DC power source (not shown) so that a set field current flows through the rotor winding 13. The power generated by the excitation circuit is transmitted as AC via the non-contact power supply unit 18 , converted to DC by the rectifier circuit 19 , and supplied to the rotor coil 13 .

[0019] Wound-field synchronous rotating electric machines have advantages over permanent magnet synchronous motors (PMSMs), such as: (1) variable field flux can be expected to improve efficiency in the medium-high speed / low torque operating range, and the constant output range can be expanded; and (2) they are not affected by supply instability of permanent magnets using rare earths, etc. For this reason, in recent years, they have also been increasingly used as a driving force source for the wheels of electric vehicles and hybrid vehicles. For this reason, although an EESM is exemplified as the rotating electric machine 1 in this embodiment, the rotating electric machine 1 may also be a PMSM.

[0020] 1 and 2, the input member 2, input gear 21, counter gear mechanism 3, and differential gear mechanism 4 are arranged on the first axial side L1 with respect to the rotary electric machine 1. As described above, the input member 2, which rotates integrally with the input gear 21, is connected to the rotor shaft 20 so as to rotate integrally with the rotor shaft 20. The input member 2 is rotatably supported on the case 9 via an input bearing B2 (first bearing). The input bearings B2 are arranged on both sides of the input gear 21 in the axial direction L. When distinguishing between the input bearings B2, the bearing arranged on the first axial side L1 with respect to the input gear 21 will be referred to as the first input bearing B21, and the bearing arranged on the second axial side L2 with respect to the input gear 21 will be referred to as the second input bearing B22.

[0021] The counter gear mechanism 3 is rotatably supported relative to the case 9 via a counter bearing B3 (second bearing). Specifically, a counter shaft 30, to which a first counter gear 31 and a second counter gear 32 are connected, is rotatably supported relative to the case 9 by counter bearings B3 arranged at two locations in the axial direction L. The first counter gear 31 is arranged on a first axial side L1 relative to the second counter gear 32. The counter shaft 30 is rotatably supported relative to the case 9 by the first counter bearing B31 arranged on the first axial side L1 relative to the first counter gear 31 and the second counter bearing B32 arranged on the second axial side L2 relative to the second counter gear 32.

[0022] In this embodiment, the first counter gear 31 that meshes with the input gear 21 has a larger diameter than the input gear 21. As a result, the rotational speed of the input member 2 is reduced and power is transmitted to the counter shaft 30. For this reason, the frictional force in the bearings is greater in the input bearing B2 than in the counter bearing B3, and the amount of heat generated by friction also tends to be greater.

[0023] The differential gear mechanism 4 is rotatably supported relative to the case 9 via a differential bearing B4. Specifically, the differential case 42 is rotatably supported relative to the case 9 by a first differential bearing B41 disposed on a first axial side L1 relative to the differential case 42 and a second differential bearing B42 disposed on a second axial side L2 relative to the differential case 42. In this embodiment, the differential input gear 41 meshing with the second counter gear 32 has a larger diameter than the second counter gear 32. As a result, the rotational speed is further reduced compared to the counter shaft 30, and power is transmitted to the differential case 42, which rotates integrally with the differential input gear 41. For this reason, the frictional force in the bearing is greater in the counter bearing B3 than in the differential bearing B4, and the amount of heat generated by friction also tends to be greater.

[0024] In this embodiment, a bevel gear type differential gear mechanism 4 is illustrated. The differential gear mechanism 4 includes a plurality of differential pinion gears 44 housed in a differential case 42, and a pair of differential side gears 45. The differential pinion gears 44 are rotatably supported by differential pinion shafts 43 that are fixed to the differential case 42 and rotate integrally with the differential case 42. A plurality of differential pinion shafts 43 are provided radially (for example, in a cross shape) along a radial direction R based on the third axis A3, and the plurality of differential pinion gears 44 are also arranged at intervals in the radial direction R. The pair of differential side gears 45 mesh with the plurality of differential pinion gears. The differential side gears 45 are arranged to rotate about the third axis A3 as a rotation axis. Of the pair of differential side gears 45, the first differential side gear 45 is arranged on a first axial side L1 relative to the differential pinion shaft 43, and the second differential side gear 45 is arranged on a second axial side L2 relative to the differential pinion shaft 43.

[0025] In this embodiment, the first differential side gear 45 arranged on the first axial side L1 is connected to the first drive shaft DS, and the first drive shaft DS is connected to the first wheel W. In addition, the second differential side gear 45 arranged on the second axial side L2 is connected to the connecting shaft JS, and the connecting shaft JS is connected to the second drive shaft DS, and the second drive shaft DS is connected to the second wheel W.

[0026] Although a bevel gear type differential gear mechanism 4 has been exemplified here, the differential gear mechanism 4 may also be a planetary gear mechanism. For example, if the differential gear mechanism 4 is a double pinion type planetary gear mechanism, a member that rotates integrally with the ring gear corresponds to the output member.

[0027] In this embodiment, oil passages for circulating oil are provided in the case 9 so that lubricating oil can be appropriately supplied to the input bearing B2, counter bearing B3, and differential bearing B4 described above. As will be described in detail later, the case 9 is provided with a first oil passage 71 that supplies oil from an oil supply source to the input bearing B2 (first bearing), a second oil passage 72 that branches off from the first oil passage 71 and supplies oil to the counter bearing B3 (second bearing), and a third oil passage 73 that branches off from the first oil passage 71 and supplies oil to the differential bearing B4 (third bearing) (see FIG. 3, etc.).

[0028] The location where the oil passage is formed is not limited to the outer wall portion that separates the outside from the inside of the case 9, but also includes support wall portions and the like formed inside the case 9 to support rotating members (input member 2, countershaft 30, etc.). Furthermore, "the case 9 has an oil passage" is not limited to a configuration in which the oil passage is formed integrally with a member that constitutes the case 9, such as the outer wall portion or support wall portion of the case 9, but also includes a configuration in which an oil passage formed by a piping member or the like is fixed to the case 9.

[0029] Hereinafter, the configuration of the oil passage will be described together with the configuration of the case 9 with reference to Fig. 3 and Fig. 4. Fig. 3 is a side view of the vehicle drive device 10 from the first axial side L1. Fig. 4 is a side view (front view) of the vehicle drive device 10 from the first front-rear side X1.

[0030] The case 9 includes a first housing chamber E1 that houses the power transmission mechanism TA, such as the rotating electric machine 1, input member 2, input gear 21, counter gear mechanism 3, and differential gear mechanism 4, and a second housing chamber E2 that is partitioned from the first housing chamber E1 and houses an electric circuit unit EU that includes a control device that drives and controls the rotating electric machine 1, an inverter, a smoothing capacitor, etc. The case 9 includes a case main body 90 that forms the core of the first housing chamber E1 and the second housing chamber E2, a first cover 91, a second cover 92, and a third cover 93.

[0031] The case body 90 includes a cylindrical portion having openings on both sides in the axial direction L, and a box-shaped portion having a side wall portion forming a rectangular opening extending from the peripheral wall of the cylindrical portion to one side in the front-rear direction X (here, the second front-rear direction side X2). The first cover 91 is a lid member that closes the opening on the first axial side L1 of the cylindrical portion of the case body 90 from the first axial side L1 (see FIGS. 1 and 3). The second cover 92 is a lid member that closes the opening on the second axial side L2 of the cylindrical portion of the case body 90 from the second axial side L2 (see FIG. 4). The third cover 93 is a lid member that closes the opening on the second front-rear direction side X2 of the box-shaped portion of the case body 90. A first storage chamber E1 is formed in a space surrounded by the inner wall of the cylindrical portion of the case body 90, the first cover 91, and the second cover 92. In addition, a second storage chamber E2 is formed in a space surrounded by the outer wall of the cylindrical portion of the case main body 90, the side wall of the box-shaped portion, and the third cover 93.

[0032] Since the electric circuit unit EU is accommodated in the second accommodation chamber E2 of the case 9, the case 9 is also provided with a first connector CN1 to which power wiring from a high-voltage DC power supply (not shown) with a rated voltage of 200 volts or more is connected. The case 9 is also provided with a second connector CN2 to which power wiring of about 12 volts that supplies drive power to the control devices in the electric circuit unit EU and signal wiring that is connected to control devices higher than the electric circuit unit EU, such as a vehicle control device (not shown) that controls the entire vehicle and various sensors, etc. Although details will be described later, a coolant supply port Wi, which serves as an inlet for coolant for cooling the power transmission mechanism TA and the inverter, smoothing capacitor, etc. of the electric circuit unit EU, and a coolant discharge port Wo, which serves as an outlet for the coolant, are also provided on the case 9 and on a member attached to the case 9 (for example, an oil cooler OC).

[0033] In the present embodiment, as shown in Fig. 3, a first oil passage 71, a second oil passage 72, and a third oil passage 73 are formed in the first cover 91. As shown in Figs. 1 and 3, the first cover 91 includes a protruding portion 99 that extends along the first cover 91 and is formed to protrude from an outer surface 91a (surface on the first axial side L1) of the first cover 91 to the outside of the case 9 (the first axial side L1) along the axial direction L. The first oil passage 71, the second oil passage 72, and the third oil passage 73 are formed in the protruding portion 99. Note that, in the present embodiment, an embodiment is illustrated in which the protruding portion 99 is formed to protrude from the outer surface 91a of the first cover 91 to the outside of the case 9 along the axial direction L, but the protruding portion 99 may be formed to protrude from an inner surface 91b of the first cover 91 to the inside of the case 9 along the axial direction L (the second axial side L2).

[0034] Such protrusions 99 can also serve as reinforcing ribs that reinforce the first cover 91 against the load acting on the first cover 91 in the axial direction L from the power transmission mechanism TA. Compared to a configuration in which a separate reinforcing rib is provided on the first cover 91, this simplifies the structure of the first cover 91 and makes it easier to suppress an increase in weight.

[0035] Naturally, this does not preclude a configuration in which the first oil passage 71, the second oil passage 72, and the third oil passage 73 are separately provided within the case 9, regardless of such reinforcing ribs.

[0036] As shown in FIG. 3 , the first oil passage 71 is formed to supply oil supplied from an oil supply source to the input bearing B2 disposed on the first axis A1. The second oil passage 72 and the third oil passage 73 are formed by branching off from the first oil passage 71. The second oil passage 72 branching off from the first oil passage 71 is formed to supply oil to the counter bearing B3 disposed on the second axis A2 below the first axis A1 on the side V2. Similarly, the third oil passage 73 branching off from the first oil passage 71 is formed to supply oil to the differential bearing B4 disposed on the third axis A3 below the first axis A1 on the side V2. Of the oil supplied from the oil supply source to the first oil passage 71, the remaining oil that has been supplied to the input bearing B2 is distributed to the second oil passage 72 and the third oil passage 73.

[0037] As described above, in this embodiment, the first oil passage 71, the second oil passage 72, and the third oil passage 73 are formed in the first cover 91 disposed on the first axial side L1. Oil is supplied from the first oil passage 71 to the first input bearing B21, and it is preferable that oil be supplied to the second input bearing B22 via an oil passage (not shown) formed along the axial direction L on the radial inner side R1 of the input member 2, for example.

[0038] In this embodiment, the protrusion 99 in which the second oil passage 72 is formed extends to a position V2 below the second axis A2. The oil supplied from the first oil passage 71 to the second oil passage 72 is supplied to the first counter bearing B31 from an oil supply hole 72h formed in the protrusion 99 at a position corresponding to the counter bearing B3 in the up-down direction V (for example, a position at least partially overlapping with the counter bearing B3 when viewed in the axial direction). As with the input bearing B2, it is preferable that oil be further supplied to the second counter bearing B32 via an oil passage (not shown) formed along the axial direction L on the radially inner side R1 of the counter shaft 30.

[0039] The oil flows through the second oil passage 72, is supplied to the oil supply hole 72h, and the remaining oil flows through an oil passage formed in the protrusion 99 and is discharged into the case 9. Here, the oil passage downstream of the oil supply hole 72h is referred to as the fourth oil passage 74. The oil discharged into the case 9 flows along the inner wall of the case 9 toward the lower side V2. An oil return hole 77 communicating with the oil reservoir P (see FIG. 4) is formed below the case 9. As shown in FIG. 5, which is an enlarged side view of the vehicle drive system 10 from the first axial side L1 with the first cover 91 open, the oil discharged into the case 9 through the fourth oil passage 74 is supplied to the oil reservoir P through the oil return hole 77. The fourth oil passage 74 can be said to be an oil passage that supplies the remaining oil supplied from the second oil passage 72 to the counter bearing B3 to the oil reservoir P. Note that the oil after lubricating the input bearing B2 and the counter bearing B3 also falls down inside the case 9. Such oil is also supplied to the oil reservoir P through the oil return hole 77.

[0040] In this embodiment, an oil pump (not shown) that sucks in and discharges oil stored in oil reservoir P is disposed inside case 9. The oil discharged from the oil pump is supplied to first oil passage 71. Therefore, the oil pump corresponds to the supply source of oil to first oil passage 71. Note that the oil supply source to first oil passage 71 is not limited to the form in which oil is directly supplied from the oil pump to first oil passage 71, and a catch tank that temporarily stores oil discharged from the oil pump and oil scooped up by a rotating member of the power transmission mechanism TA (for example, differential input gear 41) can also be used as the supply source of oil to first oil passage 71.

[0041] Similar to the first oil passage 71, the third oil passage 73 supplies oil to the first differential bearing B41 disposed on the first axial side L1. It is preferable that the second differential bearing B42 disposed on the second axial side L2 on the opposite side of the differential case 42 in the axial direction L be supplied with oil from an oil passage (not shown) that is connected to the third oil passage 73 and formed along the axial direction L, or from an oil passage other than the third oil passage 73.

[0042] As described above, the differential gear mechanism 4 of this embodiment is configured by accommodating a plurality of bevel gears inside the differential case 42. The oil remaining after being supplied from the third oil passage 73 to the differential bearing B4 is preferably supplied to parts requiring lubrication, such as the differential pinion shaft 43, differential pinion gear 44, and differential side gear 45, which are housed inside the differential case 42. That is, the third oil passage 73 is preferably connected to the fifth oil passage 75, which supplies oil to these parts requiring lubrication. The fifth oil passage 75 can be said to be an oil passage that supplies the oil remaining after being supplied from the third oil passage 73 to the differential bearing B4 to parts requiring lubrication other than the input bearing B2, the counter bearing B3, and the differential bearing B4.

[0043] In the present embodiment, the first oil passage 71, the second oil passage 72, and the third oil passage 73 have different flow path cross-sectional areas. Specifically, the flow path cross-sectional area of the first oil passage 71 is larger than the flow path cross-sectional areas of the second oil passage 72 and the third oil passage 73, and the flow path cross-sectional area of the second oil passage 72 is larger than the flow path cross-sectional area of the third oil passage 73. In one aspect, for example, the flow path cross-sectional area of the first oil passage 71 is preferably larger than the sum of the flow path cross-sectional areas of the second oil passage 72 and the third oil passage 73. Note that the flow path cross-sectional area is related to the ease of oil flow, and therefore, when the flow path cross-sectional area differs depending on the location in the flow path of each oil passage, the flow path cross-sectional area at the narrowest location in the entire flow path of each oil passage is used for comparison.

[0044] 3, the second oil passage 72 and the third oil passage 73 are disposed on a lower side V2 relative to the first oil passage 71. Because oil flows downward through the oil passages due to gravity, if the flow path cross-sectional areas of the second oil passage 72 and the third oil passage 73 branching off from the first oil passage 71 are larger than the cross-sectional area of the first oil passage 71, there is a risk that sufficient oil may not be supplied from the first oil passage 71 to the input bearing B2. If the flow path cross-sectional areas of the second oil passage 72 and the third oil passage 73 are smaller than the flow path cross-sectional area of the first oil passage 71, or more preferably, if the sum of the flow path cross-sectional areas of the second oil passage 72 and the third oil passage 73 is smaller than the flow path cross-sectional area of the first oil passage 71, sufficient oil can be easily supplied from the first oil passage 71 to the input bearing B2.

[0045] In conventional vehicles using an internal combustion engine as a driving force source for the wheels W, the cooling water, whose temperature is increased by heat exchange with the internal combustion engine, is used as a heating source. However, in vehicles without an internal combustion engine, such as electric vehicles, or in vehicles with an internal combustion engine that is sometimes stopped, such as hybrid vehicles, the number of heat sources available for heating that can be used for heating is fewer than in conventional vehicles. For this reason, electric vehicles and hybrid vehicles are increasingly being equipped with electric heaters for heating, or using heat pump systems for heating as well as cooling. Naturally, using an electric heater increases electricity consumption. Furthermore, even in the case of a heat pump system, when the outside temperature is low, the amount of heat pumped from the outside air decreases, which can increase the load on the air conditioner compressor and other components, resulting in increased electricity consumption.

[0046] The vehicle drive system 10 of this embodiment is configured to effectively utilize the heat absorbed by the oil from the bearings as a heat source for heating or the like by lubricating the bearings as described above, thereby improving the energy efficiency of the vehicle as a whole. As shown in Fig. 4, the vehicle drive system 10 includes an oil cooler OC (heat exchanger) that exchanges heat between the oil supplied from an oil reservoir P, which is a region formed in the lower part of the case 9 and in which the oil accumulates, and the heat medium. In this embodiment, the oil pump draws oil from the oil reservoir P and discharges it to the oil cooler OC. After heat exchange between the heat medium and the oil in the oil cooler OC, the oil is supplied to the first oil passage 71.

[0047] Here, the heat medium in the oil cooler OC serving as a heat exchanger is coolant. In this embodiment, as shown in FIG. 4, the oil cooler OC is attached to the outside of the case 9. The coolant is supplied from a coolant supply port Wi shown in FIGS. 3 and 4, and after cooling the electric circuit unit EU (inverter, smoothing capacitor, etc.) and the rotating electric machine 1 (e.g., stator 15), is supplied to the oil cooler OC. That is, oil and coolant are supplied from the inside of the case 9 to the oil cooler OC, and the cooled oil is supplied back into the case 9. The coolant is discharged to the outside of the vehicle drive device 10 from a coolant discharge port Wo of the oil cooler OC. The discharged coolant can exchange heat with the refrigerant of the air conditioner in an air conditioner heat exchanger (chiller or water-cooled condenser, not shown). The coolant can also exchange heat with the coolant of the battery cooler in a battery cooler of a DC power supply. Since the performance of a DC power supply decreases in a low-temperature environment, it is preferable to be able to heat the DC power supply to an appropriate temperature when the temperature of the DC power supply is low, such as when starting a vehicle.

[0048] Note that oil is also supplied to locations other than the first oil passage 71, the second oil passage 72, and the third oil passage 73. Therefore, the oil absorbs heat from locations to be lubricated or cooled other than the input bearing B2, the counter bearing B3, and the differential bearing B4. For example, the rotor coil 13 and the stator coil 17, which overheat when a current flows through them, are also cooled by the oil. Specifically, the rotor coil 13 and the stator coil 17 are cooled by applying oil to the rotor coil ends 13e protruding from the end of the rotor 11 in the axial direction L and the stator coil ends 17e protruding from the end of the stator 15 in the axial direction L. According to this embodiment, heat can also be recovered and effectively utilized from the oil that has cooled the rotor coil 13 and the stator coil 17.

[0049] The "heat medium" that exchanges heat with the oil supplied from the oil reservoir P is not limited to coolant, but may be an "air conditioner refrigerant" or a "battery cooler coolant." In addition, although the present embodiment illustrates a configuration in which the oil cooler OC is provided outside the case 9, the oil reservoir P itself may be configured to function as the oil cooler OC. In other words, the "heat exchange unit" is not limited to a configuration in which heat is exchanged between the oil supplied from the oil reservoir P via, for example, an oil pump and the heat medium, but may be a configuration in which heat is exchanged between the oil stored in the oil reservoir P and the heat medium.

[0050] As described above, the flow path cross-sectional area of the first oil passage 71 is larger than the flow path cross-sectional area of the second oil passage 72 and the flow path cross-sectional area of the third oil passage 73, and the flow path cross-sectional area of the second oil passage 72 is larger than the flow path cross-sectional area of the third oil passage 73. In addition, the frictional force at the input bearing B2 is larger than the frictional force at the counter bearing B3 and the differential bearing B4. A larger amount of oil can be supplied to the input bearing B2, which has a larger frictional force and is likely to generate a larger amount of heat, and heat can be recovered appropriately.

[0051] In the vehicle drive system 10, the oil path that lubricates and cools the power transmission mechanism TA is preferably formed so as to supply an appropriate amount of oil to each of the lubrication target points while appropriately recovering heat from the power transmission mechanism TA through heat exchange. According to this embodiment, in the vehicle drive system 10 having three mutually parallel rotating shafts, a structure is realized that can appropriately supply oil to the lubrication target points arranged on each shaft, and it is also easy to effectively utilize the heat recovered from the lubrication target points.

[0052] The vehicle drive device (10) described above will be briefly summarized below.

[0053] In one aspect, a vehicle drive device (10) includes a rotating electric machine (1) having a rotor (11), an input member (2) connected to the rotor (11) so as to rotate integrally with the rotor (11), an output member (42) drivingly connected to a wheel (W), a speed reduction mechanism (21, 3, 41) that reduces the rotation of the input member (2) and transmits the reduced rotation to the output member (42), and a case (9) that accommodates the rotating electric machine (1), the input member (2), and the speed reduction mechanism (21, 3, 41). The reduction gear mechanism (21, 3, 41) includes a counter gear mechanism (3) including an input gear (21) connected to the input member (2) so as to rotate integrally with the input member (2), a first counter gear (31) meshing with the input gear (21), and a second counter gear (32) connected to the first counter gear (31) so as to rotate integrally with the first counter gear (31), and a counter gear mechanism (3) meshing with the second counter gear (32) and connected to the output member (42). and an output gear (41) connected to the output member (42) so as to rotate relative to the input member (2), the input member (2) is rotatably supported with respect to the case (9) via a first bearing (B2), the counter gear mechanism (3) is rotatably supported with respect to the case (9) via a second bearing (B3), the output member (42) is rotatably supported with respect to the case (9) via a third bearing (B4), and a first axis (A1) which is the rotation axis of the input member (2) is aligned with the front The case (9) is disposed above (V1) the second axis (A2) which is the rotation axis of the counter gear mechanism (3) and the third axis (A3) which is the rotation axis of the output member (42), and the case (9) includes a first oil passage (71) which supplies oil from an oil supply source to the first bearing (B2), a second oil passage (72) which branches off from the first oil passage (71) and supplies oil to the second bearing (B3), and a third oil passage (73) which branches off from the first oil passage (71) and supplies oil to the third bearing (B4).

[0054] According to this configuration, the rotation of the input member (2) is reduced by the reduction gear mechanism (21, 3, 41) and transmitted to the output member (42), so that the rotation speed of the input member (2) is higher than the rotation speed of the counter gear mechanism (3) and the rotation speed of the output member (42). Therefore, the load on the first bearing (B2) supporting the input member (2) is higher than the load on the second bearing (B3) supporting the counter gear mechanism (3) and the load on the third bearing (B4) supporting the output member (42). According to this configuration, oil from a supply source is supplied to the first bearing (B2) through the first oil passage (71), and the oil is distributed to the second bearing (B3) and the third bearing (B4) through the second oil passage (72) and the third oil passage (73) branching from the first oil passage (71). Therefore, a large amount of oil can be supplied to the first bearing (B2), which has the heaviest load, and the remaining oil after supplying to the first bearing (B2) can be used to lubricate the second bearing (B3) and the third bearing (B4). That is, the amount of oil supplied from the supply unit can be kept small while an appropriate amount of oil according to the load can be supplied to each bearing. Thus, according to this configuration, in a vehicle drive device (10) having three mutually parallel rotating shafts, a structure can be realized that can appropriately supply oil to the parts to be lubricated located on each shaft.

[0055] Here, it is preferable that the flow path cross-sectional area of the first oil passage (71) is larger than the flow path cross-sectional area of the second oil passage (72) and the flow path cross-sectional area of the third oil passage (73), and that the flow path cross-sectional area of the second oil passage (72) is larger than the flow path cross-sectional area of the third oil passage (73).

[0056] With this configuration, the largest amount of oil can be supplied to the first bearing (B2), which has the heaviest load, and more oil can be supplied to the second bearing (B3), which has the second heaviest load after the first bearing (B2), than to the third bearing (B4). Therefore, an appropriate amount of oil can be supplied to each bearing according to the load.

[0057] Preferably, the vehicle drive device (10) further includes an oil reservoir (P) formed in a lower portion of the case (9) as an area where oil accumulates, and a heat exchange section (OC) that performs heat exchange between the oil accumulated in the oil reservoir (P) or the oil supplied from the oil reservoir (P) and a heat medium, and the case (9) includes a fourth oil passage (74) that supplies the oil remaining after being supplied from the second oil passage (72) to the second bearing (B3) to the oil reservoir (P), and a fifth oil passage (75) that supplies the oil remaining after being supplied from the third oil passage (73) to the third bearing (B4) to locations requiring lubrication other than the first bearing (B2), the second bearing (B3), and the third bearing (B4).

[0058] According to this configuration, the oil, which has reached a relatively high temperature, can be quickly returned to the oil reservoir (P) via the first bearing (B2) and the second bearing (B3), which are bearings with a larger load than the third bearing (B4). Therefore, the heat of the oil can be efficiently recovered in the heat exchange unit (OC) before the oil temperature drops.

[0059] Furthermore, in the vehicle drive device (10), the direction along the first axis (B2) is the axial direction, and the case (9) has a cover portion (91) that covers an accommodation chamber (E1) in which the rotating electric machine (1), the input member (2), and the reduction mechanism (21, 3, 41) are accommodated from one side (L1) in the axial direction (L), and it is preferable that the first oil passage (71), the second oil passage (72), and the third oil passage (73) are formed in a protrusion portion (99) that extends along the cover portion (91) and is formed to protrude in the axial direction (L) from an inner surface (91b) or an outer surface (91a) of the cover portion (91).

[0060] According to this configuration, the protrusions (99) formed on the cover portion (91) for forming the first oil passage (71), the second oil passage (72), and the third oil passage (73) can function to reinforce the cover portion (91) against an axial load acting on the cover portion (91) from the power transmission mechanism (TA) extending from the input member (2) to the output member (42). Therefore, according to this configuration, it is easy to ensure the strength of the cover portion (91) while suppressing an increase in its weight, while forming the first oil passage (71), the second oil passage (72), and the third oil passage (73) in the cover portion (91). [Explanation of symbols]

[0061] 1: rotating electric machine, 2: input member, 3: counter gear mechanism (reduction mechanism), 9: case, 10: vehicle drive device, 11: rotor, 21: input gear (reduction mechanism), 31: first counter gear, 32: second counter gear, 41: differential input gear (output gear, reduction mechanism), 42: differential case (output member), 71: first oil passage, 72: second oil passage, 73: third oil passage, 74: fourth oil passage, 75: fifth oil passage, 91: first cover (cover part), 91a: outer surface, 91b: inner surface, 99: protrusion, A1: first shaft (first shaft center), A2: second shaft (second shaft center), A3: third shaft (third shaft center), B2: input bearing (first bearing), B3: counter bearing (second bearing), B4: differential bearing (third bearing), DS: drive shaft, E1: first housing chamber (housing chamber for rotating electrical machine, input member, and reduction mechanism), L: axial direction, OC: oil cooler (heat exchange section), P: oil reservoir, V1: upper side, W: wheel

Claims

1. a rotating electric machine having a rotor; an input member coupled to the rotor so as to rotate integrally with the rotor; an output member drivingly connected to the wheels; a speed reduction mechanism that reduces the rotation speed of the input member and transmits the reduced rotation speed to the output member; a case that accommodates the rotating electric machine, the input member, and the reduction mechanism, The reduction mechanism is an input gear coupled to the input member so as to rotate integrally with the input member; a counter gear mechanism including a first counter gear meshing with the input gear and a second counter gear connected to the first counter gear so as to rotate integrally with the first counter gear; an output gear that meshes with the second counter gear and is connected to the output member so as to rotate integrally with the output member, the input member is rotatably supported with respect to the case via a first bearing, the counter gear mechanism is rotatably supported relative to the case via a second bearing, the output member is rotatably supported with respect to the case via a third bearing, a first axis that is a rotation axis of the input member is disposed above a second axis that is a rotation axis of the counter gear mechanism and a third axis that is a rotation axis of the output member, The case includes a first oil passage that supplies oil from an oil supply source to the first bearing, a second oil passage that branches off from the first oil passage and supplies oil to the second bearing, and a third oil passage that branches off from the first oil passage and supplies oil to the third bearing.

2. A flow path cross-sectional area of the first oil passage is larger than a flow path cross-sectional area of the second oil passage and a flow path cross-sectional area of the third oil passage, The vehicle drive device according to claim 1 , wherein a flow path cross-sectional area of the second oil passage is larger than a flow path cross-sectional area of the third oil passage.

3. an oil reservoir formed in a lower portion of the case as a region where oil accumulates; A heat exchange unit that performs heat exchange between the oil stored in the oil reservoir or the oil supplied from the oil reservoir and a heat medium, 3. The vehicle drive device according to claim 1, wherein the case includes a fourth oil passage that supplies the remaining oil supplied from the second oil passage to the second bearing to the oil reservoir, and a fifth oil passage that supplies the remaining oil supplied from the third oil passage to the third bearing to locations requiring lubrication other than the first bearing, the second bearing, and the third bearing.

4. The direction along the first axis is defined as an axial direction, the case includes a cover portion that covers an accommodation chamber that accommodates the rotating electric machine, the input member, and the reduction mechanism from one side in the axial direction, 3. The vehicle drive device according to claim 1, wherein the first oil passage, the second oil passage, and the third oil passage are formed within a protrusion portion that extends along the cover portion and protrudes in the axial direction from an inner surface or an outer surface of the cover portion.

Images