Drive device

Abstract

To realize an art which achieves small energy loss caused by an oil being stirred by a rotor while cooling both of a stator core and a stator coil properly.SOLUTION: A drive device 100 includes: a rotary electric machine 1; a case 9; an oil pump OP configured to suction an oil from a suction port 70 and discharge the oil; and an oil passage 6. The case 9 includes: a first chamber 9A in which the rotary electric machine 1 is housed; and a second chamber 9B in which the suction port 70 is disposed. The oil passage 6 includes: a supply port 71 which is open in the first chamber 9A to supply a cooling oil to a stator coil; a first oil passage 61 connecting the oil pump OP with the supply port 71; a core cooling passage 60 which is disposed in at least one of the interior of the stator core 11a and a position along a surface of the stator core 11a and through which the cooling oil of the stator core 11a flows; a second oil passage 62 connecting the oil pump OP with the core cooling passage 60; and a third oil passage 63 connecting the core cooling passage 60 with the second chamber 9B.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a drive device including a rotating electric machine, a case that houses the rotating electric machine, an oil pump, and an oil flow path through which oil discharged from the oil pump flows. [Background technology]

[0002] An example of such a drive device is disclosed in Japanese Patent Laid-Open Publication No. 2022-123545 (Patent Document 1). Hereinafter, in the description of the background art, reference numerals in parentheses refer to those in Patent Document 1. The drive device of Patent Document 1 includes a motor (1) as a rotating electric machine, a housing (4) as a case, an oil pump (not shown), and a first oil passage (11) and a second oil passage (12) as oil flow paths. The first oil passage (11) is an oil passage for distributing oil supplied from the oil pump to the coil ends (6a) of the coil (6). The second oil passage (12) is an oil passage for flowing oil around the outer periphery of the stator core, which is the core of the stator (3), and is provided so as to branch off from the first oil passage (11). The coil ends (6a) are cooled by the oil dispersed from the first oil passage (11) to the coil ends (6a), and the stator core is cooled by the oil flowing through the second oil passage (12). Then, both the oil after cooling the coil ends (6a) and the oil after cooling the stator core are stored in an oil pan area near the bottom surface of the housing (4). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-123545 Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, in the drive device of Patent Document 1, both the oil after cooling the stator core and the oil after cooling the stator coil wound around the stator coil are stored in a reservoir (an oil pan area in Patent Document 1) formed in the lower part of the case that houses the rotating electrical machine. As a result, the oil level in the reservoir tends to become high, which may result in large energy loss due to the oil being stirred by the rotor.

[0005] Therefore, it is desirable to realize a technology that can appropriately cool both the stator core and the stator coil while minimizing the energy loss caused by the rotor stirring the oil. [Means for solving the problem]

[0006] The drive device of the present disclosure is a drive device comprising: a rotating electric machine having a stator and a rotor; a case that houses the rotating electric machine; an oil pump that draws in and discharges oil from an intake port provided in the case; and an oil flow path through which the oil discharged from the oil pump flows, wherein the stator comprises a stator core and a stator coil wound around the stator core, and the case comprises a first chamber that houses the rotating electric machine and a second chamber that is separate from the first chamber and in which the intake port is located, and the oil flow path comprises: a supply port that opens in the first chamber and supplies cooling oil to the stator coil; a first oil path that connects the oil pump and the supply port; a core cooling path that is arranged at least either inside the stator core or at a position along the surface of the stator core and through which oil for cooling the stator core flows; a second oil path that connects the oil pump and the core cooling path; and a third oil path that connects the core cooling path and the second chamber.

[0007] According to this configuration, the stator core can be appropriately cooled by the oil flowing through the core cooling passage, while the stator coil can be appropriately cooled by the oil supplied from the supply port. Furthermore, according to this configuration, the oil after cooling the stator core is discharged not into the first chamber, which houses the rotating electrical machine, but into a second chamber, which is separate from the first chamber. Therefore, compared to when the oil after cooling the stator core is discharged into the first chamber, the amount of oil accumulating in the first chamber can be reduced, making it easier to reduce energy loss due to oil agitation by the rotor. As described above, according to this configuration, it is possible to appropriately cool both the stator core and the stator coil, while minimizing energy loss due to oil agitation by the rotor.

[0008] Further features and advantages of the drive device will become apparent from the following description of an embodiment thereof, which is given with reference to the drawings. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a skeleton diagram of a drive device according to an embodiment; [Figure 2] Schematic diagram of a drive device according to an embodiment. [Figure 3] FIG. 1 is a perspective view showing the inside of a drive device according to an embodiment; [Figure 4] 1 is a perspective view of a case according to an embodiment; [Figure 5] FIG. 1 is a diagram showing a core cooling passage according to an embodiment; [Figure 6] FIG. 1 is a diagram showing a first example of a core cooling passage according to an embodiment; [Figure 7] FIG. 10 is a diagram showing a second example of a core cooling passage according to the embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of a drive device will be described with reference to the drawings. In this embodiment, a vehicle drive device that drives a vehicle (wheels) is exemplified as the drive device, but the drive device is not limited to a vehicle (wheels).

[0011] In this specification, 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.

[0012] In this specification, the term "rotating electric machine" is used as a concept that includes motors, generators, and motor-generators that function as both motors and generators as needed. Furthermore, in this specification, with regard to the arrangement of two elements, "overlapping when viewed from 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 partial area where the imaginary line intersects both of the two elements.

[0013] 1 and 2, the drive device 100 includes a rotating electric machine 1, a case 9, an oil pump OP, and an oil flow path 6. In this embodiment, the drive device 100 further includes output members (2A, 2B) and a gear mechanism 3 that transmits power between the rotating electric machine 1 (specifically, a rotor 12, which will be described later) and the output members (2A, 2B). In this embodiment, the drive device 100 is a vehicle drive device, and the output members (2A, 2B) are drivingly connected to wheels W of a vehicle (a vehicle on which the drive device 100 is mounted). The drive device 100 transmits the driving force of the rotating electric machine 1 to the wheels W to run the vehicle.

[0014] As shown in FIG. 1, in this embodiment, the drive unit 100 includes, as output members, a first output member 2A drivingly connected to a first wheel W and a second output member 2B drivingly connected to a second wheel W. The first wheel W and the second wheel W are a pair of left and right wheels W of a vehicle. The gear mechanism 3 transmits power between the rotor 12 and the pair of output members (2A, 2B). In this embodiment, each of the first output member 2A and the second output member 2B corresponds to an "output member."

[0015] The rotating electric machine 1 is electrically connected to an electricity storage device such as a battery or a capacitor. The rotating electric machine 1 is electrically connected to the electricity storage device, for example, via an inverter. The rotating electric machine 1 generates driving force by powering using the electric power stored in the electricity storage device. The rotating electric machine 1 also generates electricity using driving force transmitted from the wheels W, thereby charging the electricity storage device. A vehicle on which the drive device 100 is mounted may also be configured to be provided with a driving force source (for example, an internal combustion engine) separate from the rotating electric machine 1, and the drive device 100 may transmit driving force from the rotating electric machine 1 and the separate driving force source to the wheels (W1, W2).

[0016] As shown in FIG. 1, the rotating electric machine 1 includes a stator 11 and a rotor 12. Here, the direction along the rotation axis X of the rotor 12 is referred to as the "axial direction L," one side of the axial direction L is referred to as the "first axial side L1," and the other side of the axial direction L is referred to as the "second axial side L2." The direction circumferentially around the rotation axis X is referred to as the "circumferential direction C." The direction perpendicular to the rotation axis X is referred to as the "radial direction R," and the side of the radial direction R toward the rotation axis X is referred to as the "radially inner side R1," and the opposite side is referred to as the "radially outer side R2." When the drive unit 100 is in use (in this embodiment, when the drive unit 100 is mounted on a vehicle), the direction along the vertical direction is referred to as the "up-down direction V," the vertical upper side is referred to as the "upper side V1," and the vertical lower side is referred to as the "lower side V2." In this embodiment, the drive unit 100 is used with the axial direction L oriented along a horizontal plane (here, when mounted on a vehicle).

[0017] The stator 11 includes a stator core 11a and a stator coil 10 wound around the stator core 11a. The stator coil 10 is wound around the stator core 11a so as to form a first coil end portion 11b that protrudes toward a first axial side L1 relative to the stator core 11a and a second coil end portion 11c that protrudes toward a second axial side L2 relative to the stator core 11a. The stator core 11a is formed with a plurality of slots 13 (see FIG. 5 ) that extend in the axial direction L and are aligned in the circumferential direction C, and the stator coil 10 is wound around the plurality of slots 13.

[0018] The stator core 11a is fixed to the case 9 (specifically, a case portion 90, which will be described later). The stator core 11a is formed in a cylindrical shape extending in the axial direction L. As shown in FIGS. 5 to 7, in this embodiment, the stator core 11a is provided with protrusions 14 for attaching the stator core 11a to the case 9, and a main body portion, which is the portion of the stator core 11a excluding the protrusions 14, is formed in a cylindrical shape. The protrusions 14 are formed to protrude radially outward R2 from an outer peripheral surface S1 of the stator core 11a (specifically, the main body portion) and extend in the axial direction L. A plurality of (four in this example) protrusions 14 are arranged along the outer peripheral surface S1, dispersed in the circumferential direction C. The stator core 11a is fixed to the case 9 with the end faces of the protrusions 14 in the axial direction L abutting against attachment portions 93 (see FIG. 4) provided on the case 9. Here, the stator core 11a is fastened to the case 9 by bolts 16 (see FIG. 3) inserted into insertion holes formed in the protrusions 14. As shown in FIG. 5, in this embodiment, the stator core 11a is fixed to the case 9 so that one of the plurality of protrusions 14 is disposed at the top of the stator core 11a and another of the plurality of protrusions 14 is disposed at the bottom of the stator core 11a.

[0019] As shown in FIG. 1, the rotor 12 includes a rotor core 12a. The rotor core 12a is formed in a cylindrical shape extending in the axial direction L. The rotor core 12a is supported by the case 9 so as to be rotatable relative to the stator core 11a. The rotor core 12a is connected to a rotor shaft 12b formed to extend along the axial direction L so as to rotate integrally with the rotor core 12a. The rotor core 12a is supported by the case 9 via the rotor shaft 12b. In this embodiment, the rotating electric machine 1 is an inner rotor type rotating electric machine, and the rotor core 12a is disposed radially inward R1 relative to the stator core 11a. In this embodiment, a permanent magnet is provided in the rotor core 12a.

[0020] The gear mechanism 3 includes a transmission shaft and gears, and may include engaging elements such as a clutch and a brake. In this embodiment, the gear mechanism 3 includes a reducer 4 and a differential gear mechanism 5. The reducer 4 and the differential gear mechanism 5 are arranged on the rotation axis X. That is, in this embodiment, the rotating electric machine 1 and the gear mechanism 3 are arranged to be aligned in the axial direction L. The rotating electric machine 1 is arranged on a first axial side L1 with respect to the gear mechanism 3. Here, the reducer 4 is arranged on the first axial side L1 with respect to the differential gear mechanism 5, and the rotating electric machine 1 is arranged on the first axial side L1 with respect to the reducer 4. The rotating electric machine 1 is arranged to overlap with the gear mechanism 3 (here, both the reducer 4 and the differential gear mechanism 5) when viewed in the axial direction along the axial direction L.

[0021] The reducer 4 reduces the rotation speed of the rotor 12. In this embodiment, the reducer 4 is a planetary gear reducer. In the example shown in FIG. 1, the reducer 4 includes a sun gear SG, a carrier CR, a first ring gear RG1, and a second ring gear RG2. The sun gear SG is connected to the rotor 12 (specifically, the rotor shaft 12b) so as to rotate integrally with the rotor 12. The first ring gear RG1 is fixed to a case 9, and the second ring gear RG2 is supported by the case 9 so as to be rotatable relative to the case 9. The carrier CR supports a first pinion gear PG1 that meshes with the sun gear SG and the first ring gear RG1, and a second pinion gear PG2 that meshes with the second ring gear RG2 so as to rotate integrally.

[0022] The differential gear mechanism 5 distributes the rotation transmitted from the rotating electric machine 1 (here, the rotation transmitted from the reducer 4) to the first output member 2A and the second output member 2B. In this embodiment, the differential gear mechanism 5 is a bevel gear type differential gear mechanism. In the example shown in FIG. 1 , the differential gear mechanism 5 includes a differential case 51, a shaft member 52, a first bevel gear 53, and a second bevel gear 54. The differential case 51 is configured to rotate about a rotation axis X. Here, the differential case 51 is connected to the second ring gear RG2 so as to rotate integrally with the second ring gear RG2. The first bevel gear 53 is supported by a shaft member 52 that rotates integrally with the differential case 51, and rotates (spins) about the shaft member 52 and also rotates (revolves) about the rotation axis X. The second bevel gear 54 meshes with the first bevel gear 53 and rotates about the rotation axis X.

[0023] The second bevel gears 54 are provided on both sides of the shaft member 52 in the axial direction L. The first output member 2A is connected to the second bevel gear 54 arranged on the first axial side L1 of the shaft member 52 so as to rotate integrally with the second bevel gear 54, and the second output member 2B is connected to the second bevel gear 54 arranged on the second axial side L2 of the shaft member 52 so as to rotate integrally with the second bevel gear 54. The output members (2A, 2B) are, for example, members formed integrally with the second bevel gear 54. The differential gear mechanism 5 distributes the rotation transmitted to the differential case 51 to a pair of second bevel gears 54 arranged separately on both sides of the shaft member 52 in the axial direction L, thereby distributing the rotation to the first output member 2A and the second output member 2B.

[0024] As shown in FIG. 1, a vehicle equipped with a drive unit 100 is provided with a first drive shaft DS1 drivingly connected to a first wheel W and a second drive shaft DS2 drivingly connected to a second wheel W. The drive shafts (DS1, DS2) are connected to the wheels W via, for example, constant velocity joints. A first output member 2A is connected to the first drive shaft DS1 so as to rotate integrally with the first drive shaft DS1, and a second output member 2B is connected to the second drive shaft DS2 so as to rotate integrally with the second drive shaft DS2. In the example shown in FIG. 1, the first output member 2A is connected to the first drive shaft DS1 via a connecting shaft 20 extending radially inward R1 with respect to the rotor shaft 12b along the axial direction L.

[0025] The case 9 accommodates the rotating electric machine 1. In this embodiment, the case 9 also accommodates the gear mechanism 3. As shown in a simplified form in FIG. 2, the case 9 includes a first chamber 9A and a second chamber 9B that is separate from the first chamber 9A. In this embodiment, the first chamber 9A and the second chamber 9B are separated from each other by a cover member 95 (see FIG. 3), which will be described later. Alternatively, the first chamber 9A and the second chamber 9B may be separated from each other by a wall (compartment wall) included in the case 9. In this case, the communication section 8, which will be described later, is provided in the partition wall, for example. The first chamber 9A and the second chamber 9B may be partially communicated with each other by a communication passage, a communication opening, or the like. The rotating electric machine 1 is accommodated in the first chamber 9A, and the gear mechanism 3 is accommodated in the second chamber 9B. The first chamber 9A is disposed on a first axial side L1 relative to the second chamber 9B.

[0026] The case 9 contains oil. The oil is used to cool and lubricate the rotating electrical machine 1 and the gear mechanism 3. The oil supplied to heat-generating parts such as the stator 11 cools the heat-generating parts, and the oil supplied to parts to be lubricated such as gears and bearings lubricates the parts to be lubricated. The oil is stored in reservoirs (A1, A2) (described later) formed in the lower part of the case 9 (part of the lower side V2). The oil stored in the reservoirs (A1, A2) is supplied to the parts to be lubricated, such as the heat-generating parts and parts to be lubricated, and then returned to the reservoirs (A1, A2). In the drive device 100, such oil circulation is achieved by driving the oil pump OP. In addition to driving the oil pump OP, oil circulation may also be achieved by having rotating members such as gears scoop up the oil.

[0027] As shown in FIG. 2, the drive unit 100 includes an oil pump OP that draws in and discharges oil from a suction port 70 provided in the case 9. The suction port 70 is disposed in the second chamber 9B. The suction port 70 is disposed so as to draw in oil from a second reservoir A2 (described later) formed in the second chamber 9B. The oil pump OP (specifically, a suction port) is connected to the suction port 70 by a fourth oil passage 64 (suction oil passage). For example, a strainer that filters the oil is disposed in the fourth oil passage 64. In this embodiment, the oil pump OP is an electric pump driven by an electric motor (a dedicated electric motor separate from the rotating electric machine 1). The oil pump OP may be a mechanical pump driven by power (in other words, the driving force of the rotating electric machine 1) transmitted through a power transmission path between the rotating electric machine 1 and the output members (2A, 2B).

[0028] The drive unit 100 includes an oil flow path 6 through which oil discharged from an oil pump OP flows. Note that the "oil path (oil flow path)" includes both a sealed oil path and an open oil path (for example, a path through which oil flows along a wall surface, etc.). For example, an oil cooler that exchanges heat between the oil and a refrigerant (for example, cooling water) is disposed in the oil flow path 6 through which oil discharged from the oil pump OP (specifically, a discharge port) flows.

[0029] As shown in Fig. 2, the oil passage 6 includes a supply port 71, a core cooling passage 60, a first oil passage 61, a second oil passage 62, and a third oil passage 63. Note that Fig. 2 illustrates a case where the upstream portions of the first oil passage 61 and the second oil passage 62 are configured by a common oil passage. The oil cooler described above is disposed in this common oil passage, for example. The location where the first oil passage 61 and the second oil passage 62 branch off from this common oil passage may be inside or outside the case 9. Note that the first oil passage 61 and the second oil passage 62 may also be formed independently of each other in their respective upstream portions.

[0030] The supply port 71 opens to the first chamber 9A. The supply port 71 supplies cooling oil to the stator coil 10. The stator coil 10 is cooled by the oil supplied from the supply port 71 to the stator coil 10. In this embodiment, a supply port 71 (hereinafter referred to as the "first supply port") for supplying oil to the first coil end portion 11b and a supply port 71 (hereinafter referred to as the "second supply port") for supplying oil to the second coil end portion 11c are provided. The first coil end portion 11b is cooled by the oil supplied from the first supply port to the first coil end portion 11b, and the second coil end portion 11c is cooled by the oil supplied from the second supply port to the second coil end portion 11c.

[0031] The supply port 71 is provided, for example, in a supply pipe arranged in the first chamber 9A. The supply port 71 may be provided on the inner surface of the peripheral wall of the case 9, on the surface of a wall arranged inside the case 9, or the like. The supply port 71 is configured, for example, to drip oil onto the coil end portions (11b, 11c) from the upper side V1. The supply port 71 may also be configured to spray oil onto the coil end portions (11b, 11c) from the side. The supply port 71 may also be configured to supply oil to the coil end portions (11b, 11c) via other members such as a coil end cover.

[0032] The core cooling path 60 is an oil path through which oil for cooling the stator core 11a flows. The stator core 11a is cooled by the oil flowing through the core cooling path 60. The core cooling path 60 will be described in detail later.

[0033] The first oil passage 61 is an oil passage that connects the oil pump OP and the supply port 71. The second oil passage 62 is an oil passage that connects the oil pump OP and the core cooling passage 60 (specifically, the inlet 60i of the core cooling passage 60). The oil discharged from the oil pump OP is supplied to the supply port 71 through the first oil passage 61 and is used to cool the stator coil 10. In this embodiment, the first oil passage 61 is connected to both the first supply port and the second supply port at the downstream end, and the oil discharged from the oil pump OP is supplied to both the first supply port and the second supply port through the first oil passage 61. In addition, the oil discharged from the oil pump OP is supplied to the core cooling passage 60 through the second oil passage 62 and is used to cool the stator core 11a.

[0034] The oil pump OP may be disposed inside or outside the case 9. In the present embodiment, the oil pump OP is disposed outside the case 9. Therefore, the fourth oil passage 64 connects the suction port 70 and the oil pump OP via a first connection portion 72A (see FIGS. 3 and 4) provided in the case 9. In addition, the first oil passage 61 and the second oil passage 62 connect the oil pump OP and the supply port 71 or the core cooling passage 60 via a second connection portion 72B (see FIGS. 3 and 4) provided in the case 9.

[0035] The third oil passage 63 is an oil passage that connects the core cooling passage 60 (specifically, the outlet 60o of the core cooling passage 60) and the second chamber 9B. After flowing through the core cooling passage 60 and cooling the stator core 11a, the oil is discharged through the third oil passage 63 into the second chamber 9B. In this embodiment, the core cooling passage 60 and the third oil passage 63 are oil paths that are separated from the internal space of the first chamber 9A. As shown in FIG. 2, a second reservoir A2 in which oil is collected is formed at the bottom of the second chamber 9B. The oil discharged through the third oil passage 63 to the second chamber 9B is collected in the second reservoir A2.

[0036] As described above, the oil after cooling the stator core 11a is discharged not into the first chamber 9A housing the rotating electrical machine 1 but into the second chamber 9B, which is a separate chamber from the first chamber 9A. This minimizes the amount of oil accumulating in the first chamber 9A, thereby reducing energy loss due to oil agitation by the rotor 12. This configuration, which makes it difficult for the rotor 12 to agitate the oil, also minimizes oil foaming due to agitation by the rotor 12. This reduces the risk of oil blowing out of the case 9 through a breather that connects the inside and outside of the case 9 (so-called breather blow). Furthermore, since the drive unit 100 can accumulate oil in the core cooling passage 60, etc., the amount of oil accumulating in each of the first chamber 9A and the second chamber 9B can be controlled by controlling the oil pump OP. This allows for control of the ratio (balance) between the magnitude of oil agitation resistance due to the rotating electrical machine 1 and the gear mechanism 3 and the efficiency of lubrication and cooling.

[0037] In addition to the second storage section A2, the drive device 100 also includes a first storage section A1 formed below the first chamber 9A. The drive device 100 also includes a communication section 8 that connects the first storage section A1 to the second chamber 9B. Therefore, oil supplied to the stator coil 10 from the supply port 71 accumulates in the first storage section A1 after the stator coil 10 cools, and at least a portion of the oil accumulated in the first storage section A1 flows to the second chamber 9B via the communication section 8. For example, by arranging the communication section 8 on the upper side V1 above the lowest portion of the first storage section A1, a configuration can be achieved in which a portion of the oil accumulated in the first storage section A1 flows to the second chamber 9B via the communication section 8. Furthermore, by arranging the communication section 8 at the lowest portion of the first storage section A1, a configuration can be achieved in which all of the oil accumulated in the first storage section A1 flows to the second chamber 9B via the communication section 8.

[0038] The stator core 11a and the rotor core 12a are present between a portion of the first chamber 9A on the axial first side L1 (the portion where the first coil end portion 11b is accommodated) and a portion of the first chamber 9A on the axial second side L2 (the portion where the second coil end portion 11c is accommodated). Therefore, the flow of oil between the portion of the first chamber 9A on the axial first side L1 and the portion of the first chamber 9A on the axial second side L2 is limited or regulated by the stator core 11a and the rotor core 12a. Therefore, the oil after cooling the first coil end portion 11b accumulates in a first reservoir A1 on the axial first side L1, which is formed on the axial first side L1 relative to the stator core 11a and the rotor core 12a, and the oil after cooling the second coil end portion 11c accumulates in a first reservoir A1 on the axial second side L2, which is formed on the axial second side L2 relative to the stator core 11a and the rotor core 12a. The drive unit 100 has, as the communication section 8, a first communication section 8A that connects the first storage section A1 on the second axial side L2 with the second chamber 9B, and a second communication section 8B that connects the first storage section A1 on the first axial side L1 with the second chamber 9B.

[0039] 3 and 4, in this embodiment, the case 9 includes a case portion 90 to which the stator core 11a is fixed. Here, the case portion 90 is formed in a cylindrical shape having openings on both sides in the axial direction L. Although not shown, the case 9 includes a second case portion fixed to the case portion 90 so as to close the opening on the first axial side L1 of the case portion 90, and a third case portion fixed to the case portion 90 so as to close the opening on the second axial side L2 of the case portion 90.

[0040] As shown in Fig. 4, the case portion 90 includes a peripheral wall portion 92 that covers the stator core 11a from the radially outer side R2. The case portion 90 further includes a wall portion 91 that is formed to extend from an end portion of the peripheral wall portion 92 on the second axial side L2 toward the radially outer side R2. The peripheral wall portion 92 includes an inner peripheral surface S2 that is disposed along the outer peripheral surface S1 of the stator core 11a. In this embodiment, the inner peripheral surface S2 of the peripheral wall portion 92 includes a first portion S2a that is disposed along the outer surface of the cylindrical portion (main body portion) of the stator core 11a, and a second portion S2b that is disposed along the outer surface of the protrusion 14 formed on the stator core 11a.

[0041] As shown in FIG. 3, in this embodiment, the first chamber 9A and the second chamber 9B are separated by a cover member 95 fixed to a surface of the wall portion 91 facing the second axial side L2. The cover member 95 is arranged to cover the portion of the rotating electrical machine 1 on the second axial side L2 from the second axial side L2 and the radially outer side R2. Here, the cover member 95 is arranged to close the opening on the second axial side L2 of the hole forming the second oil passage 62 (see FIG. 4). The space covered by the cover member 95 from the second axial side L2 and the radially outer side R2 forms the portion of the first chamber 9A on the second axial side L2 (the portion in which the second coil end portion 11c is accommodated). The space on the radially outer side R2 relative to the cover member 95 within the case 9, together with the space on the second axial side L2 relative to the cover member 95 within the case 9, form the second chamber 9B.

[0042] As shown in FIG. 3, in this embodiment, a cutout portion formed in the cover member 95 to communicate the inside and outside of the cover member 95 constitutes a first communication portion 8A. In the example shown in FIG. 3, the first communication portion 8A is disposed above the rotation axis X on the side V1. However, the first communication portion 8A may be disposed below the rotation axis X on the side V2. Furthermore, a plurality of first communication portions 8A may be disposed dispersedly in the circumferential direction C. As shown in FIG. 4, in this embodiment, the second communication portion 8B extends from the first axial side L1 of the first chamber 9A to the second axial side L2 and opens into a portion of the wall portion 91 that is not covered by the cover member 95 (i.e., a portion facing the second chamber 9B) (see FIG. 3). Similarly, the third oil passage 63 is also formed to open into a portion of the wall portion 91 that is not covered by the cover member 95 (see FIG. 3).

[0043] Hereinafter, the core cooling passage 60 in the drive device 100 of this embodiment will be described in detail with reference to Fig. 3 to Fig. 7. In Fig. 5 to Fig. 7, the outline of the oil flow in the core cooling passage 60 and the second oil passage 62 is indicated by dashed arrows. In Fig. 5 to Fig. 7, the case 9 and the rotor 12 are omitted.

[0044] The core cooling passage 60 is disposed at least either inside the stator core 11a or at a position along the surface of the stator core 11a. Here, the surface of the stator core 11a includes the outer peripheral surface S1 of the stator core 11a, the inner peripheral surface of the stator core 11a, and the end surface of the stator core 11a in the axial direction L. When the core cooling passage 60 is disposed inside the stator core 11a, the core cooling passage 60 is formed by a hole or the like formed inside the stator core 11a. When the core cooling passage 60 is disposed at a position along the surface of the stator core 11a, the core cooling passage 60 is formed so as to be in contact with the surface of the stator core 11a, or so as to be adjacent to the surface of the stator core 11a via a separate member such as a wall. Thus, the term "position along the surface" includes both a position in contact with the surface and a position adjacent to the surface via a separate member.

[0045] In the present embodiment, the core cooling passage 60 is disposed at a position along the surface of the stator core 11a. Specifically, the core cooling passage 60 is disposed at a position along the outer peripheral surface S1 of the stator core 11a. Here, the core cooling passage 60 is disposed between the outer peripheral surface S1 of the stator core 11a and the inner peripheral surface S2 of the peripheral wall portion 92 in the radial direction R. Note that if the case 9 includes an inner case that fits onto the outer peripheral surface S1 of the stator core 11a and an outer case that is disposed radially outward R2 from the inner case, the core cooling passage 60 can also be disposed between the inner case and the outer case in the radial direction R, thereby being disposed at a position along the outer peripheral surface S1 of the stator core 11a.

[0046] As described above, in this embodiment, the core cooling passage 60 is disposed between the outer peripheral surface S1 of the stator core 11a and the inner peripheral surface S2 of the peripheral wall portion 92 in the radial direction R. Therefore, a recess for forming the core cooling passage 60 is provided in at least one of the outer peripheral surface S1 of the stator core 11a and the inner peripheral surface S2 of the peripheral wall portion 92. As shown in FIG. 4 , in this embodiment, a recess 94 for forming the core cooling passage 60 is formed in the inner peripheral surface S2 of the peripheral wall portion 92, and the core cooling passage 60 is formed surrounded by the recess 94 and the outer peripheral surface S1 of the stator core 11a. Here, the recess 94 is formed in both the first portion S2a and the second portion S2b of the inner peripheral surface S2 of the peripheral wall portion 92.

[0047] The recess 94 is formed to extend in the circumferential direction C, and the oil in the core cooling passage 60 flows in the circumferential direction C from the inlet 60i to the outlet 60o while being restricted or regulated from moving outward in the axial direction L (toward the side away from the center of the axial direction L of the stator core 11a) by inner walls on both sides in the axial direction L of the recess 94 (see FIG. 5). Therefore, it is preferable that portions of the inner peripheral surface S2 of the peripheral wall portion 92 on both sides in the axial direction L of the recess 94 be arranged so as to contact the outer peripheral surface S1 of the stator core 11a. As shown in Figure 4, the third oil passage 63 is formed to connect the inner surface S2 (here, the second part S2b) of the peripheral wall portion 92 and the surface of the wall portion 91 facing the second axial side L2, and the oil that reaches the outlet 60o of the core cooling passage 60 is introduced into the third oil passage 63 from an opening formed in the inner surface S2 (here, the second part S2b) of the peripheral wall portion 92, and is discharged to the second chamber 9B from an opening formed in the surface of the wall portion 91 facing the second axial side L2.

[0048] 5, in this embodiment, a pair of core cooling passages 60 are formed separately on both sides of the uppermost part of the stator core 11a in the circumferential direction C. A second oil passage 62 and a third oil passage 63 are provided for each of the pair of core cooling passages 60. One core cooling passage 60 is configured on one side of the circumferential direction C with respect to the uppermost part of the stator core 11a so as to allow oil to flow to that one side in the circumferential direction C, and the other core cooling passage 60 is configured on the other side of the circumferential direction C with respect to the uppermost part of the stator core 11a so as to allow oil to flow to that other side in the circumferential direction C.

[0049] The oil flow in the core cooling passage 60 may be along the axial direction L or along the circumferential direction C, and the oil flow direction may vary depending on the location. However, in this embodiment, the core cooling passage 60 is configured to allow oil to flow in the circumferential direction C at multiple positions in the axial direction L along the cylindrical outer peripheral surface S1 of the stator core 11a. Here, the "multiple positions in the axial direction L" may refer to multiple positions that are discretely arranged (i.e., spaced apart) in the axial direction L, or multiple positions that are continuously arranged in the axial direction L. As shown in FIGS. 6 and 7 , in this embodiment, the connection portion of the second oil passage 62 with the core cooling passage 60 is configured to allow oil to flow along the axial direction L (here, toward the second axial side L2). The core cooling passage 60 is configured to branch off from the connection portion of the second oil passage 62 at multiple positions in the axial direction L and allow oil to flow in the circumferential direction C at the multiple positions.

[0050] FIG. 6 shows an example of a case where the core cooling passage 60 is configured to allow oil to flow in the circumferential direction C at a plurality of positions discretely arranged in the axial direction L. In this example, the core cooling passage 60 is configured as a collection of a plurality of branch oil passages 60a aligned in the axial direction L. Each of the branch oil passages 60a is configured to allow oil to flow in the circumferential direction C. For example, by arranging a plurality of recesses 94 extending in the circumferential direction C at intervals in the axial direction L on the inner circumferential surface S2 of the peripheral wall portion 92, it is possible to form a plurality of branch oil passages 60a aligned in the axial direction L. In this way, configuring the core cooling passage 60 to allow oil to flow in the circumferential direction C at a plurality of positions discretely arranged in the axial direction L has the advantage of easily increasing the flow rate of oil in the core cooling passage 60.

[0051] 7 shows an example of the core cooling passage 60 causing oil to flow in the circumferential direction C at a plurality of positions that are continuously arranged in the axial direction L. For example, by forming recesses 94 as shown in FIG. 4 on the inner peripheral surface S2 of the peripheral wall portion 92, it is possible to form the core cooling passage 60 causing oil to flow in the circumferential direction C at a plurality of positions that are continuously arranged in the axial direction L. In this way, configuring the core cooling passage 60 to cause oil to flow in the circumferential direction C at a plurality of positions that are continuously arranged in the axial direction L has the advantage of easily increasing the coverage rate of the core cooling passage 60 on the outer peripheral surface S1 of the stator core 11a (the proportion of the surface that is covered by the core cooling passage 60).

[0052] Other Embodiments (1) In the above embodiment, a configuration has been described as an example in which the reduction gear 4 and the differential gear mechanism 5 are arranged on the rotation axis X. However, the present disclosure is not limited to such a configuration, and one or both of the reduction gear 4 and the differential gear mechanism 5 may be arranged on an axis different from the rotation axis X.

[0053] (2) In the above embodiment, the configuration in which the reducer 4 is a planetary gear reducer has been described as an example. However, the present disclosure is not limited to such a configuration. For example, the reducer 4 may be a counter reduction mechanism. Also, the gear mechanism 3 may not include the reducer 4.

[0054] (3) In the above embodiment, the differential gear mechanism 5 is a bevel gear type differential gear mechanism. However, the present disclosure is not limited to such a configuration, and the differential gear mechanism 5 may be a planetary gear type differential gear mechanism, for example. In this case, the differential gear mechanism 5 is configured to distribute the rotation transmitted to the ring gear to the first output member 2A that rotates integrally with the sun gear and the second output member 2B that rotates integrally with the carrier, for example.

[0055] (4) In the above embodiment, a configuration in which the gear mechanism 3 includes a differential gear mechanism 5 has been described as an example. However, the present disclosure is not limited to such a configuration, and the gear mechanism 3 may also be configured not to include a differential gear mechanism 5. In this case, the gear mechanism 3 is configured to transmit power between the rotor 12 and one output member (for example, an output shaft connected to the wheels W). As described above, the configuration of the gear mechanism 3 shown in the above embodiment is one example, and the configuration of the gear mechanism 3 can be changed as appropriate. Also, the drive device 100 may be configured not to include the gear mechanism 3, and the rotation of the rotor 12 may be output directly from the drive device 100.

[0056] (5) In the above embodiment, the driving device 100 is described as a vehicle driving device. However, the object to be driven by the driving device 100 is not limited to a vehicle (wheels W), and the driving device 100 may also drive a machine tool, a pump, an air conditioner compressor, etc.

[0057] (6) Note that the configurations disclosed in the above-described embodiments can be applied in combination with configurations disclosed in other embodiments (including combinations of embodiments described as other embodiments) as long as no contradictions arise. Regarding other configurations, the embodiments disclosed in this specification are merely examples in all respects. Therefore, various modifications can be made as appropriate within the scope of the present disclosure.

[0058] [Summary of this embodiment] The above-described embodiments of the drive device will be summarized below.

[0059] The drive device (100) includes a rotating electric machine (1) having a stator (11) and a rotor (12), a case (9) that houses the rotating electric machine (1), an oil pump (OP) that draws in oil from a suction port (70) provided in the case (9) and discharges it, and an oil flow path (6) through which the oil discharged from the oil pump (OP) flows, wherein the stator (11) includes a stator core (11a) and a stator coil (10) wound around the stator core (11a), and the case (9) includes a first chamber (9A) that houses the rotating electric machine (1), and a second chamber (9B) that is separate from the first chamber (9A) and through which the suction port (70) The oil flow path (6) comprises a supply port (71) that opens in the first chamber (9A) and supplies cooling oil to the stator coil (10), a first oil passage (61) that connects the oil pump (OP) and the supply port (71), a core cooling passage (60) that is arranged at least either inside the stator core (11a) or at a position along the surface of the stator core (11a) and through which oil for cooling the stator core (11a) flows, a second oil passage (62) that connects the oil pump (OP) and the core cooling passage (60), and a third oil passage (63) that connects the core cooling passage (60) and the second chamber (9B).

[0060] According to this configuration, the stator core (11a) can be appropriately cooled by the oil flowing through the core cooling passage (60), while the stator coil (10) can be appropriately cooled by the oil supplied through the supply port (71). Furthermore, according to this configuration, the oil after cooling the stator core (11a) is discharged not to the first chamber (9A) in which the rotating electric machine (1) is housed, but to the second chamber (9B), which is a chamber separate from the first chamber (9A). Therefore, compared to when the oil after cooling the stator core (11a) is discharged to the first chamber (9A), the amount of oil accumulating in the first chamber (9A) can be reduced, and energy loss due to oil agitation by the rotor (12) can be reduced. As described above, according to this configuration, it is possible to appropriately cool both the stator core (11a) and the stator coil (10), while reducing energy loss due to oil agitation by the rotor (12).

[0061] Here, it is preferable to have a configuration including a first storage section (A1) formed in a lower part of the first chamber (9A) and a communication section (8) that connects the first storage section (A1) and the second chamber (9B), wherein the oil supplied to the stator coil (10) from the supply port (71) accumulates in the first storage section (A1) after the stator coil (10) has cooled, and at least a part of the oil accumulated in the first storage section (A1) flows to the second chamber (9B) via the communication section (8).

[0062] According to this configuration, at least a portion of the oil accumulated in the first reservoir (A1) can flow to the second chamber (9B), and therefore, even if the oil accumulates in the first reservoir (A1) after cooling the stator coil (10), the oil level in the first reservoir (A1) can be kept low. Therefore, the oil level in the first reservoir (A1) formed in the lower part of the first chamber (9A) can be kept low while supplying the stator coil (10) with the amount of oil necessary for cooling it. As a result, the stator coil (10) can be appropriately cooled while the above-mentioned energy loss can be kept low.

[0063] In addition, the direction along the rotation axis (X) of the rotor (12) is defined as an axial direction (L), and the direction circumferentially around the rotation axis (X) is defined as a circumferential direction (C), and it is preferable that the core cooling passage (60) is configured to flow oil in the circumferential direction (C) along the cylindrical outer peripheral surface (S1) of the stator core (11a) at a plurality of positions in the axial direction (L).

[0064] According to this configuration, the stator core (11a) can be cooled efficiently.

[0065] The oil pump further includes output members (2A, 2B) drivingly connected to a wheel (W), and a gear mechanism (3) that transmits power between the rotor (12) and the output members (2A, 2B), wherein the direction along the rotation axis (X) of the rotor (12) is defined as an axial direction (L), the rotating electric machine (1) and the gear mechanism (3) are arranged so as to be aligned in the axial direction (L), the gear mechanism (3) is housed in the second chamber (9B), a second reservoir (A2) that collects oil is formed at the bottom of the second chamber (9B), and the intake port (70) is configured to draw in the oil from the second reservoir (A2).

[0066] According to the drive device (100) of the present disclosure, as described above, the oil after cooling the stator core (11a) is discharged to the second chamber (9B), which makes it easy to ensure a large amount of oil remaining in the second chamber (9B). According to this configuration, the gear mechanism (3) is accommodated in the second chamber (9B), which makes it easy to ensure a large amount of oil. Therefore, the gear mechanism (3) can be easily lubricated using the oil remaining in the second reservoir (A2) formed in the lower part of the second chamber (9B). Furthermore, according to this configuration, the oil pump (OP) draws oil from the second reservoir (A2), which collects a relatively large amount of oil, which reduces the possibility of the oil pump (OP) drawing air.

[0067] It is sufficient for the drive device according to the present disclosure to achieve at least one of the above-described effects. [Explanation of symbols]

[0068] 1: rotating electric machine, 2A: first output member (output member), 2B: second output member (output member), 3: gear mechanism, 6: oil flow path, 8: communication portion, 9: case, 9A: first chamber, 9B: second chamber, 10: stator coil, 11: stator, 11a: stator core, 12: rotor, 60: core cooling path, 61: first oil path, 62: second oil path, 63: third oil path, 70: intake port, 71: supply port, 100: drive unit, A1: first reservoir, A2: second reservoir, C: circumferential direction, L: axial direction, OP: oil pump, S1: outer peripheral surface, W: wheel, X: rotation axis

Claims

1. A drive device comprising: a rotating electric machine having a stator and a rotor; a case that houses the rotating electric machine; an oil pump that draws in oil from a suction port provided in the case and discharges it; and an oil flow path through which the oil discharged from the oil pump flows, The stator includes a stator core and a stator coil wound around the stator core, the case includes a first chamber in which the rotating electric machine is housed, and a second chamber separate from the first chamber and in which the intake port is disposed, The oil flow path is a supply port that opens in the first chamber and supplies cooling oil to the stator coil; a first oil passage connecting the oil pump and the supply port; a core cooling passage disposed inside the stator core and / or at a position along a surface of the stator core, through which oil for cooling the stator core flows; a second oil passage connecting the oil pump and the core cooling passage; a third oil passage connecting the core cooling passage and the second chamber.

2. a first storage section formed in a lower portion of the first chamber; and a communication section that communicates the first storage section with the second chamber, 2. The drive device according to claim 1, wherein the oil supplied to the stator coil from the supply port accumulates in the first reservoir after the stator coil is cooled, and at least a portion of the oil accumulated in the first reservoir flows into the second chamber via the communication portion.

3. A direction along the rotation axis of the rotor is defined as an axial direction, and a direction around the rotation axis is defined as a circumferential direction, The drive device according to claim 1 or 2, wherein the core cooling passage is configured to cause oil to flow in the circumferential direction at a plurality of positions in the axial direction along a cylindrical outer peripheral surface of the stator core.

4. an output member drivingly connected to a wheel; and a gear mechanism transmitting power between the rotor and the output member, The direction along the rotation axis of the rotor is defined as the axial direction, the rotating electric machine and the gear mechanism are arranged to be aligned in the axial direction, The gear mechanism is housed in the second chamber, a second reservoir portion for storing oil is formed at a lower portion of the second chamber; The drive device according to claim 1 or 2, wherein the suction port is provided to suck in oil from the second reservoir.

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