Vehicle drive device

Abstract

The present invention relates to a drive unit for a vehicle, the housing comprising: a housing body (90) having a lower surface opening (90a) opening toward a lower side (V2); and a lower surface cover (93) mounted to the housing body (90) in a manner that closes the lower surface opening (90a) and forming at least a portion of an oil reservoir (P). The lower surface cover (93) comprises: a suction port (96) opening toward the oil reservoir (P); and a pump mounting portion (94) formed in the portion that forms the inner side of the housing. An oil pump (OP) is mounted in the pump mounting portion (94) and connected to the suction port (96) via an oil passage formed in the lower surface cover (93).

Description

Technical Field

[0001] The present invention relates to a drive device for a vehicle, comprising: a rotary motor; a power transmission mechanism for transmitting power between the rotor of the rotary motor and an output component connected to a wheel; a housing for housing the rotary motor and the power transmission mechanism; and an oil pump for drawing in and discharging oil accumulated in an oil reservoir at the lower part of the housing. Background Technology

[0002] A transmission oil filter module is disclosed in Japanese Patent Publication No. 2023-513899 (Patent Document 1). In the following description of the background art, the reference numerals shown in parentheses are those of Patent Document 1. The transmission oil filter module (1) of Patent Document 1 is as described in that document... Figures 1-4 As shown, it includes a housing (2), a pump (3), and an oil pan (6). In Patent Document 1... Figure 5 Figure 7 shows the flow of oil within the transmission oil filter module (1).

[0003] Patent Document 1: Japanese Patent Publication No. 2023-513899

[0004] However, in such a vehicle drive system, if the amount of oil in the housing increases, the oil stirring resistance based on the rotor and power transmission mechanism increases, and the transmission efficiency of the driving force in the vehicle drive system may decrease. Therefore, it is desirable to reduce the amount of oil in the housing, but if the amount of oil in the housing is reduced, proper lubrication of the oil pump may become difficult. This point is not mentioned in Patent Document 1.

[0005] Therefore, it is desirable to achieve a technology that can properly lubricate the oil pump and reduce the amount of oil in the housing. Summary of the Invention

[0006] The vehicle drive device disclosed herein includes: a rotary motor having a rotor; an output component that is driven to a wheel; a power transmission mechanism that transmits power between the rotor and the output component; a housing that houses the rotary motor and the power transmission mechanism; and an oil pump that draws in and discharges oil accumulated in an oil reservoir in the lower part of the housing through an intake port. The housing includes: a housing body having a lower surface opening facing downwards; and a lower surface cover mounted on the housing body to close the lower surface opening, forming at least a portion of the oil reservoir. The lower surface cover includes: the intake port opening into the oil reservoir; and a pump mounting portion formed in the portion becoming the inner side of the housing. The oil pump is mounted on the pump mounting portion and connected to the intake port via an oil passage formed in the lower surface cover.

[0007] According to this structure, the oil pump is installed in the portion of the lower surface cover that forms the inner side of the housing, thus facilitating the immersion of at least a portion of the oil pump in the oil reservoir. Therefore, even if the oil level in the oil reservoir is set low, the oil pump can be properly lubricated by immersing at least a portion of the oil pump in the oil. As the amount of oil in the housing decreases, the oil level in the oil reservoir decreases, but according to this structure, as described above, even if the oil level in the oil reservoir is set low, the oil pump can be properly lubricated, thereby enabling proper lubrication of the oil pump and reducing the amount of oil in the housing.

[0008] Furthermore, according to this structure, the oil pump is connected to the suction port via an oil passage formed on the lower surface cover, thus making it easier to shorten the oil passage from the suction port to the oil pump. Therefore, according to this structure, it also has the advantage of easily reducing the suction resistance of the oil based on the oil pump.

[0009] Further features and advantages of the vehicle drive system will become clear from the following description of embodiments illustrated with reference to the accompanying drawings. Attached Figure Description

[0010] Figure 1 This is an exploded perspective view of the vehicle drive unit according to the embodiment.

[0011] Figure 2 This is a schematic diagram of a vehicle drive unit according to an embodiment.

[0012] Figure 3 This is an external view of the vehicle drive unit according to the embodiment.

[0013] Figure 4 This is a side view of the interior of the vehicle drive unit according to the embodiment.

[0014] Figure 5 This is a perspective view of the lower surface cover of the embodiment.

[0015] Figure 6 This is a partial cross-sectional view of the vehicle drive unit according to the embodiment. Detailed Implementation

[0016] The embodiments of the vehicle drive system are described with reference to the accompanying drawings.

[0017] In the following description, "drive connection" refers to a state in which two rotating elements are connected in a manner capable of transmitting driving force. This includes a state in which the two rotating elements are connected in a manner that allows them to rotate as a whole, or a state in which the two rotating elements are connected via one or more transmission components in a manner capable of transmitting driving force. Such transmission components include various components that transmit rotation at the same speed or at varying speeds, such as shafts, gear mechanisms, belts, chains, etc. Furthermore, transmission components may also include engagement devices that selectively transmit rotation and driving force, such as friction engagement devices, meshing engagement devices, etc. However, when the rotating elements of a planetary gear mechanism are referred to as "drive connection," it means a state in which they are driven connected without being connected via other rotating elements possessed by the planetary gear mechanism.

[0018] like Figure 1 as well as Figure 2 As shown, the vehicle drive unit 10 includes: a rotary motor 1 with a rotor 11; an output component 40 driven by the wheels W; a power transmission mechanism TA for transmitting power between the rotor 11 and the output component 40; and a housing 9 that houses the rotary motor 1 and the power transmission mechanism TA. Furthermore, in Figure 1 In this embodiment, several components, including a portion of the cover assembly constituting the housing 9, are omitted. The power transmission mechanism TA includes an input component 2, a reversing gear mechanism 3, and a differential gear mechanism 4. The input component 2 is connected to the rotor 11 of the rotary motor 1 in a manner that allows it to rotate integrally with the rotor 11. In this embodiment, the input component 2 is splinedly connected to the rotor shaft 20 of the rotor 11, and rotates integrally with both the rotor 11 and the rotor shaft 20. Alternatively, the rotor shaft 20 and the input component 2 may be the same component. The differential gear mechanism 4 distributes the driving force transmitted from the rotary motor 1 to a pair of output components 40 that are driven and connected to a pair of wheels W. The housing 9, in addition to the rotary motor 1 and the power transmission mechanism TA, also houses the output components 40.

[0019] In this embodiment, the vehicle drive unit 10 includes a deceleration mechanism that reduces the rotational speed of the input component 2 and transmits it to the output component 40. For example... Figure 2 As shown, in this embodiment, the reduction mechanism is configured to include an input gear 21, a reversing gear mechanism 3, and a differential input gear 41. The input gear 21 is connected to the input component 2 in a manner that allows it to rotate integrally with the input component 2. The input gear 21 can be integrally formed with the same component as the input component 2, which is a shaft component, or it can be formed with a different component from the input component 2, and can be integrated with the input component 2 by welding or the like. Similarly, the first reversing gear 31 and the second reversing gear 32, which will be described later, can also be the same component as the shaft component (reversing shaft 30) or a different component. The differential input gear 41 can also be the same component as the differential housing 42 or a different component.

[0020] The reversing gear mechanism 3 includes a first reversing gear 31 and a second reversing gear 32. Both the first reversing gear 31 and the second reversing gear 32 are connected to the reversing shaft 30 in a manner that allows them to rotate integrally. The first reversing gear 31 meshes with the input gear 21, and the second reversing gear 32 meshes with the differential input gear 41. The differential input gear 41 is connected to the differential housing 42 in a manner that allows it to rotate integrally with the differential housing 42.

[0021] like Figure 2 As shown, the rotary motor 1 (rotor 11) and the input component 2 are mounted on the first shaft A1 (first axis). The reversing gear mechanism 3 is mounted on a different axis parallel to the first shaft A1, namely the second shaft A2 (second axis). The output component 40 and the differential gear mechanism 4 are mounted on a different axis parallel to both the first shaft A1 and the second shaft A2, namely the third shaft A3 (third axis). In this embodiment, as... Figure 1 As shown, the first axis A1 is positioned above the second axis A2 and the third axis A3 by a distance V1. Furthermore, in this embodiment, the second axis A2 is shown positioned above the third axis A3 by a distance V1, but the second axis A2 and the third axis A3 may also be positioned at the same position in the vertical direction V, and the third axis A3 may also be positioned above the second axis A2 by a distance V1.

[0022] In the following description, the direction parallel to the first axis A1, the second axis A2, and the third axis A3 is defined as the "axial direction L" of the vehicle drive unit 10. Furthermore, 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." Additionally, the direction in which rotating components revolve around their respective axes of rotation is defined as the "circumferential direction C" (see reference). Figure 1 Additionally, the directions orthogonal to the first axis A1, the second axis A2, and the third axis A3 are defined as the "radial R" based on each axis (see reference). Figure 1 Furthermore, the side closer to the axis in the radial direction R is called "radial inner side R1", and the side farther from the axis is called "radial outer side R2". In addition, when it is not necessary to distinguish which axis is used as the reference, or when the reference axis is clear, it is sometimes simply referred to as "radial R".

[0023] Furthermore, in the vehicle-mounted state where the vehicle drive unit 10 is mounted on the vehicle, the direction along the vertical direction is defined as the up-down direction V. Along the up-down direction V, the upper side is referred to as the upper side V1, and the lower side is referred to as the lower side V2. In this embodiment, in the vehicle-mounted state, the axis L is along the horizontal direction, and the axis L is orthogonal to the up-down direction V. Moreover, in this state, the direction orthogonal to the axis L and the up-down direction V is defined as the front-rear direction X. One side of the front-rear direction X is referred to as the "front-rear direction first side X1", and the other side of the front-rear direction X is referred to as the "front-rear direction second side X2".

[0024] In this embodiment, a wound-excited synchronous rotating motor (EESM) is exemplified as the rotating motor 1, having a stator 15 and a wound-excited rotor 11. The stator 15 is equipped with multi-phase (N is any natural number, N phases, for example, 3 phases) stator coils 17. The rotor structure of the wound-excited synchronous rotating motor uses an electromagnet with excitation windings (rotor coils 13) instead of permanent magnets as the excitation source. The circuit unit EU, described later, includes a control device and an excitation circuit, from which the excitation circuit controlled by the control device is connected via a contactless power supply unit 18 and a rectifier circuit 19 (see reference). Figure 2 An excitation current is supplied to the rotor coil 13. Furthermore, the excitation flux based on the electromagnet can be adjusted using this excitation current. The excitation circuit adjusts the DC voltage supplied by a DC power supply (not shown) to allow the set excitation current to flow through the rotor coil 13. The power generated by the excitation circuit is transmitted in alternating current via a contactless power supply unit 18, converted to direct current by a rectifier circuit 19, and supplied to the rotor coil 13.

[0025] Compared to permanent magnet synchronous motors (PMSMs), wound-excited synchronous rotary motors have the following advantages: (1) due to the variable excitation flux, improved efficiency can be expected in the medium-to-high speed and low torque operating range, and the constant output range can be expanded; (2) they are not affected by supply instability of permanent magnets using rare earth elements. Therefore, in recent years, the use of wound-excited synchronous rotary motors as a driving force source for wheels in electric vehicles and hybrid vehicles has also expanded. Therefore, in this embodiment, an EESM is exemplified as rotary motor 1, but rotary motor 1 can also be a PMSM.

[0026] like Figure 1 as well as Figure 2As shown, the input component 2, input gear 21, reverse gear mechanism 3, and differential gear mechanism 4 are arranged on the first axial side L1 relative to the rotary motor 1. As described above, the input component 2, which rotates integrally with the input gear 21, is connected to the rotor shaft 20 in a manner that it rotates integrally with the rotor shaft 20. The first reverse gear 31 is arranged on the first axial side L1 relative to the second reverse gear 32. In this embodiment, the diameter of the first reverse gear 31, which meshes with the input gear 21, is larger than the diameter of the input gear 21, thus slowing down the rotation of the input component 2 and transmitting it to the reverse shaft 30. Furthermore, in this embodiment, the diameter of the differential input gear 41, which meshes with the second reverse gear 32, is larger than the diameter of the second reverse gear 32, thus slowing down the rotation of the reverse shaft 30 and transmitting it to the differential housing 42, which rotates integrally with the differential input gear 41.

[0027] In this embodiment, a bevel gear type differential gear mechanism 4 is illustrated. The differential gear mechanism 4 includes a plurality of differential pinions 44 housed within a differential housing 42 and a pair of differential side gears 45. The differential pinions 44 are rotatably supported on a differential pinion shaft 43, which is fixed to the differential housing 42 and rotates integrally with the differential housing 42. The pair of differential side gears 45 mesh with the plurality of differential pinions 44. The differential side gears 45 are configured to rotate about a third axis A3. The first differential side gear 45 of the pair of differential side gears 45 is disposed on a first axial side L1 relative to the differential pinion shaft 43, and the second differential side gear 45 is disposed on a second axial side L2 relative to the differential pinion shaft 43.

[0028] In this embodiment, the differential side gear 45 is connected to the output component 40 in a manner that allows it to rotate integrally with the output component 40. The differential side gear 45 is formed integrally with the output component 40, for example. The differential gear mechanism 4 distributes the driving force transmitted from the rotary motor 1 to the differential housing 42 to a pair of differential side gears 45, thereby distributing this driving force to a pair of output components 40. The output component 40 connected to the first differential side gear 45 (the output component 40 disposed on the first axial side L1) is connected to the first drive shaft DS, which is connected to the first wheel W. Furthermore, the output component 40 connected to the second differential side gear 45 (the output component 40 disposed on the second axial side L2) is connected to the connecting shaft JS, which is connected to the second drive shaft DS, which is connected to the second wheel W.

[0029] Furthermore, a bevel gear type differential gear mechanism 4 is illustrated here, but the differential gear mechanism 4 can also be a planetary gear mechanism. For example, in the case where the differential gear mechanism 4 is a planetary gear mechanism of the double pinion type, the differential gear mechanism 4 distributes the driving force transmitted from the rotary motor 1 to the ring gear to the sun gear and the planet carrier, thereby distributing the driving force to a pair of output components 40.

[0030] like Figure 1 As shown, the housing 9 includes a first receiving chamber E1 and a second receiving chamber E2, which is divided relative to the first receiving chamber E1. The first receiving chamber E1 houses a rotary motor 1 and a power transmission mechanism TA, while the second receiving chamber E2 houses a circuit unit EU. The circuit unit EU includes a control device for driving and controlling the rotary motor 1, an inverter, a smoothing capacitor, etc. The housing 9 includes a housing body 90. The housing body 90 is the core component of both the first receiving chamber E1 and the second receiving chamber E2. In this embodiment, the housing 9 also includes a first cover 91, a second cover 92, and a third cover (not shown).

[0031] The housing body 90 includes a cylindrical portion and a box-shaped portion with openings on both sides in the axial direction L. The box-shaped portion is formed such that a side wall portion forming a rectangular opening extends from the peripheral wall of the cylindrical portion in the forward-backward direction X (here, the second side X2 in the forward-backward direction). The first cover 91 is a cover member that closes the opening of the cylindrical portion in the axial direction L1 from the first side L1 in the axial direction (see reference). Figure 1 , Figure 3 The second cover 92 is a cover component that closes the opening on the axial second side L2 of the cylindrical portion of the housing body 90 from the axial second side L2 (see reference). Figure 3 The third cover is a cover component that closes the opening on the second side X2 of the box-shaped portion of the housing body 90 in the front-rear direction. A first receiving chamber E1 is formed in the space surrounded by the inner wall of the cylindrical portion of the housing body 90, the first cover 91, and the second cover 92. In addition, a second receiving chamber E2 is formed in the space surrounded by the outer wall of the cylindrical portion of the housing body 90, the side wall of the box-shaped portion, and the third cover.

[0032] The circuit unit EU is housed in the second receiving chamber E2 of the housing 9. Therefore, a first connector CN1 is provided in the housing 9 for power wiring connection from a DC power supply (not shown) with a rated voltage of 200 volts or higher. Details will be described later. A cooling water supply port Wi, which serves as the inlet for cooling water used to cool the power transmission mechanism TA and the circuit unit EU (inverter, smoothing capacitor, etc.), and a cooling water outlet Wo, which serves as the outlet for cooling water, are also provided in the housing 9. Components (e.g., oil cooler OC) mounted on the housing 9 are also provided.

[0033] A second connector CN2 is also provided in the housing 9. Approximately 12 volts of power wiring is connected to the second connector CN2 to supply drive power to the control devices in the circuit unit EU, as well as signal wiring connecting to higher-level control devices (such as a vehicle control device not shown that controls the entire vehicle), various sensors, etc. Additionally... Figure 4 The cable 56 shown is connected directly or via another cable to the second connector CN2. Figure 5 as well as Figure 6 Cable 56 is omitted here. Cable 56 connects to connector 55 of the oil pump OP (described later) and supplies at least one of the operating power and control signal to the oil pump OP. Figure 4 In the example shown, cable 56 is configured to pass through a communication port 77 formed in the lower part of the housing body 90, and to be disposed on the second axial side L2 relative to the communication port 77. Figure 4 The oil pump OP (connector 55) is connected (on the inside of the paper). Although detailed descriptions are omitted, the oil used to lubricate the various parts of the power transmission mechanism TA is as follows: Figure 4 As indicated by the arrow, the oil is supplied through the communication port 77 to the oil storage section P (described later) located on the second axial side L2 relative to the communication port 77.

[0034] The housing 9 contains oil for cooling and lubricating the rotary motor 1 and the power transmission mechanism TA. The oil is stored in an oil reservoir P formed in the lower part (lower V2 portion) of the housing 9 (see reference). Figure 6 ).like Figure 5 as well as Figure 6 As shown, the vehicle drive unit 10 includes an oil pump OP, which draws in and discharges oil from the oil reservoir P stored in the lower part of the housing 9 (here, the lower part of the housing body 90) through the suction port 96. At the suction port 51 of the oil pump OP (see reference...) Figure 6 It is connected to the suction oil line 70, and at the discharge port 52 of the oil pump OP (refer to...) Figure 6 The system is connected to an oil discharge line 74. Oil discharged by the oil pump OP is supplied to heat-generating parts such as the rotor coil end 13e and stator coil end 17e, as well as lubrication points such as gears and bearings, before returning to the oil storage section P. In this embodiment, the vehicle drive unit 10 includes an oil cooler OC (heat exchange section) that exchanges heat between oil and a heat medium (cooling water in this embodiment). After the oil discharged by the oil pump OP exchanges heat with the heat medium in the oil cooler OC, it is supplied to the aforementioned oil supply points such as heat-generating parts and lubrication points.

[0035] The oil pump OP can be an electric pump driven by an electric motor (a dedicated electric motor different from the rotary motor 1), or a mechanical pump driven by the driving force transmitted along the power transmission path between the rotary motor 1 and the wheel W (in other words, the driving force of the rotary motor 1). In this embodiment, the oil pump OP is an electric pump. Figure 5 as well as Figure 6As shown, the oil pump OP includes a pump section 53 with a pump rotor and a motor section 54 with an electric motor. Although detailed descriptions are omitted, the pump rotor is housed in a pump chamber formed in the pump section 53. Furthermore, the pump rotor is connected to the pump shaft 50 in a manner that allows it to rotate integrally with the pump shaft 50. The motor section 54 includes a connector 55 for connecting the aforementioned cable 56, and the electric motor in the motor section 54 rotates the pump shaft 50 using electricity supplied via the cable 56. As the pump rotor connected to the pump shaft 50 rotates, oil drawn into the pump chamber from the suction port 51 is discharged from the discharge port 52. Thus, the oil pump OP includes a rotating pump rotor and a drive source (electric motor) for driving the pump rotor.

[0036] like Figure 6 As shown, the housing body 90 has a lower surface opening 90a that opens downwards towards the lower side V2. Furthermore, the housing 90 includes a lower surface cover 93 that is mounted on the housing body 90 to close the lower surface opening 90a. Figure 6 In the example shown, the mounting portion 98 formed on the lower surface cover 93 is fastened to the periphery of the lower surface opening 90a by bolts (not shown), thereby mounting the lower surface cover 93 to the housing body 90. The lower surface cover 93 forms at least a portion of the oil reservoir P. That is, the lower surface cover 93 forms at least a portion of the wall surrounding the oil reservoir P. Figure 6 As shown, the lower surface cover 93 is mounted on the housing body 90 in such a way that it forms at least the bottom wall portion of the oil reservoir P. Thus, the lower surface cover 93 functions as an oil pan. The lower surface cover 93 is positioned V2 below the rotary motor 1. Furthermore, in this embodiment, the lower surface cover 93 is configured such that, when viewed along the vertical direction V, at least a portion overlaps with the rotary motor 1.

[0037] like Figure 5 as well as Figure 6 As shown, the lower surface cover 93 has a suction port 96 that opens into the oil storage section P. Furthermore, in Figure 6 In order to indicate the location of the inlet 96, in Figure 6 The non-existent intake port 96 is represented by an imaginary line in the cross-section. For example... Figure 5 As shown, the suction port 96 is disposed on the central side of the axial direction L in the lower surface cover 93 (in other words, the oil storage section P), preferably disposed in the central part of the axial direction L in the lower surface cover 93. Furthermore, as... Figure 5 as well as Figure 6 As shown, the intake port 96 is disposed on the central side of the lower surface cover 93 (in other words, the oil storage part P) in the front-rear direction X, preferably disposed in the central part of the lower surface cover 93 in the front-rear direction X.

[0038] The lower surface cover 93 has a pump mounting portion 94 formed on the inner side of the housing 9. The oil pump OP is mounted on the pump mounting portion 94. Figure 6 As shown, a suction port 51 and a discharge port 52 are formed in the pump mounting part 94, and the oil pump OP is mounted in the pump mounting part 94 such that the pump part 53 abuts against the pump mounting part 94. Figure 6 In the example shown, the pump mounting portion 94 also has a shaft receiving portion for receiving the front end of the pump shaft 50 (the end opposite to the motor portion 54). Figure 5 As shown, in this embodiment, the lower surface cover 93 also includes a filter screen mounting portion 95 formed in the portion that forms the inner side of the housing 9. Furthermore, an oil filter screen ST is mounted on the filter screen mounting portion 95. The filter screen ST is disposed in the suction oil passage 70 described below.

[0039] The oil pump OP (specifically, the suction port 51) is connected to the suction inlet 96 via the suction oil passage 70. The oil pump OP is connected to the suction inlet 96 via an oil passage formed on the lower surface cover 93. That is, at least a portion of the suction oil passage 70 is formed on the lower surface cover 93; in this embodiment, the entire suction oil passage 70 is formed on the lower surface cover 93. The suction oil passage 70 includes an oil passage connecting the suction inlet 96 to the filter screen ST and an oil passage connecting the filter screen ST to the oil pump OP. In this embodiment, the suction oil passage 70 includes a first oil passage 71, a second oil passage 72 connected to the downstream side of the first oil passage 71, and a third oil passage 73 connected to the downstream side of the second oil passage 72. The first oil passage 71 forms an oil passage connecting the suction inlet 96 to the filter screen ST, and the second oil passage 72 and the third oil passage 73 form an oil passage connecting the filter screen ST to the oil pump OP.

[0040] At least a portion of the oil passage connecting the suction inlet 96 to the filter screen ST, and at least a portion of the oil passage connecting the filter screen ST to the oil pump OP, are formed on the lower surface cover 93. As described above, in this embodiment, the entire suction oil passage 70 is formed on the lower surface cover 93. Therefore, the entire oil passage connecting the suction inlet 96 to the filter screen ST, and the entire oil passage connecting the filter screen ST to the oil pump OP, are formed on the lower surface cover 93. That is, the entire first oil passage 71, the entire second oil passage 72, and the entire third oil passage 73 are formed on the lower surface cover 93.

[0041] The oil pump OP (specifically, discharge port 52) ​​is connected to the connection portion 97 via a discharge oil passage 74. At least a portion of the discharge oil passage 74 is formed in the lower surface cover 93; in this embodiment, the entire discharge oil passage 74 is formed in the lower surface cover 93. The connection portion 97 is provided at the end of the discharge oil passage 74 (the end opposite to the oil pump OP side). Figure 6As shown, the connecting portion 97 connects to the housing body-side oil passage 76 formed on the housing body 90 when the lower surface cover 93 is installed on the housing body 90. A sealing member is provided, for example, at the connection between the connecting portion 97 and the housing body-side oil passage 76. In this embodiment, the oil supplied from the discharge oil passage 74 to the housing body-side oil passage 76 is supplied to the oil cooler OC and then to the oil supply target area.

[0042] As described above, the lower surface cover 93 has an intake port 96, a pump mounting portion 94, and an intake oil passage 70. In this embodiment, a filter screen mounting portion 95 and an exhaust oil passage 74 are also formed. Such a lower surface cover 93 can be formed, for example, by casting and machining.

[0043] like Figure 6 As shown, in this embodiment, the surface of the lower surface cover 93 that forms the inner side of the housing 9, facing upwards towards V1, i.e., the bottom surface 93a, is arranged at an inclination relative to the horizontal. When the lower surface cover 93 is installed on the housing body 90, the bottom surface 93a becomes the bottom surface of the oil reservoir P. Furthermore, "arranged at an inclination relative to the horizontal" means that the bottom surface 93a is generally inclined relative to the horizontal, regardless of whether it has a partially formed uneven shape. In this embodiment, the portion of the lower surface cover 93 that forms the inner side of the housing 9, excluding the sidewall portion and functional portions (pump mounting portion 94, filter mounting portion 95, oil passages, etc.), is designated as the bottom surface 93a.

[0044] like Figure 6 As shown, the pump mounting part 94 is positioned on a side lower than the middle position H2 in the vertical direction V of the bottom surface 93a (here, the second side X2 in the front-rear direction). Furthermore, in Figure 6 In this embodiment, the highest position in the bottom surface 93a is designated as the upper position H1, the lowest position in the bottom surface 93a is designated as the lower position H3, and the central position between the upper position H1 and the lower position H3 is designated as the middle position H2. In this embodiment, the bottom surface 93a is inclined such that it slopes downwards towards the horizontal (here, the second side X2 in the front-rear direction) towards the lower side V2. Therefore, the end of this horizontal side of the bottom surface 93a (here, the end of the second side X2 in the front-rear direction) becomes the lowest point of the oil storage section P, and the pump mounting section 94 is positioned on this horizontal side (here, the second side X2 in the front-rear direction) that is closer to the middle position H2 in the bottom surface 93a. Figure 6 In the example shown, the pump mounting portion 94 is located at the lower end position H3 in the bottom surface 93a of the housing. Specifically, the pump mounting portion 94 is located in a side wall portion (here, a wall portion having an inner surface inclined relative to the vertical direction V) extending from the lower end position H3 of the bottom surface 93a toward the upper side V1. Figure 5 as well as Figure 6In the example shown, the connection 97 between the discharge oil passage 74 and the oil passage 76 on the main body side of the housing is located on the side that is higher than the middle position H2 in the vertical direction V of the bottom surface 93a (here, the first side X1 in the front-rear direction).

[0045] like Figure 6 As shown, in this embodiment, the pump shaft 50 of the oil pump OP is arranged at an incline relative to the horizontal along the bottom surface 93a of the casing. Furthermore, the oil level OL (e.g., the stationary oil level) in the oil reservoir P is set such that at least a portion of the pump shaft 50 is immersed in the oil. The stationary oil level is the oil level OL of the oil reservoir P in a stationary state after a certain period of time since the vehicle stopped. To prevent the pump shaft 50 from sintering, the oil level OL is set such that at least the rotatable portion of the pump shaft 50 (e.g., the portion of the pump mounting portion 94 housed in the aforementioned shaft housing) is immersed in the oil.

[0046] However, in existing vehicles that use an internal combustion engine as the driving force for the wheels (W), the cooling water, whose temperature rises through heat exchange with the internal combustion engine, serves as the heat source for heating. However, in vehicles without an internal combustion engine, such as electric vehicles, and in vehicles like hybrid vehicles where the internal combustion engine may stop even if present, the amount of heat source that can be utilized for heating is less than in existing vehicles. Therefore, electric vehicles and hybrid vehicles are equipped with electric heaters for heating, or they utilize heat pumps not only for cooling but also for heating. Of course, using an electric heater increases electricity consumption. Furthermore, in the case of a heat pump, when the outside temperature is low, the amount of heat absorbed from the outside air decreases, sometimes increasing the load on the air conditioning compressor and other components, thus increasing electricity consumption.

[0047] In the vehicle drive unit 10 of this embodiment, the oil pump OP is installed in the portion of the lower surface cover 93 that becomes the inner side of the housing 9. Therefore, as Figure 6 As shown, at least a portion of the oil pump OP can be easily immersed in the oil stored in the oil reservoir P. Even if the amount of oil in the housing 9 is reduced, the oil pump OP can be properly lubricated by immersing at least a portion of it in the oil. By reducing the amount of oil in the housing 9 in this way, the rate of oil temperature rise is easily accelerated, and heat recovery from the oil (e.g., oil supplied to heat-generating components such as the rotor coil 13 and stator coil 17) is easily achieved. Furthermore, by effectively utilizing the recovered heat as a heat source for heating and other purposes, the overall energy efficiency of the vehicle can be improved.

[0048] Here, the heat transfer medium in the oil cooler OC, which serves as the heat exchange unit, is cooling water. In this embodiment, as... Figure 3As shown, the oil cooler OC is installed outside the housing 9. Cooling water is supplied from the cooling water supply port Wi, and after cooling the circuit unit EU (inverter, smoothing capacitor, etc.) and the rotary motor 1 (e.g., stator 15), it is supplied to the oil cooler OC. That is, oil and cooling water are supplied to the oil cooler OC from inside the housing 9, and the cooled oil is then supplied back into the housing 9. Cooling water is discharged from the cooling water outlet Wo of the oil cooler OC to the outside of the vehicle drive unit 10. The discharged cooling water can exchange heat with the refrigerant of the air conditioner in an air conditioning heat exchanger (cooler, water-cooled condenser) (not shown). In addition, the cooling water can also exchange heat with the coolant of the battery cooler in the DC power supply battery cooler. The performance of the DC power supply degrades in low-temperature environments, so it is preferable to heat the DC power supply to a suitable temperature when the temperature of the DC power supply is low, such as when the vehicle is started.

[0049] Furthermore, the "heat medium" that exchanges heat with the oil inside the housing 9 is not limited to cooling water, but can also be "air conditioner refrigerant" or "battery coolant". Additionally, in this embodiment, an oil cooler OC is shown outside the housing 9, but the oil storage section P itself can also function as an oil cooler OC. In other words, the "heat exchange section" is not limited to the case where heat exchange occurs between the oil and the heat medium outside the oil storage section P, but can also occur inside the oil storage section P.

[0050] [Other Implementation Methods]

[0051] (1) In the above embodiment, the structure described is exemplified by a configuration in which the bottom surface 93a is inclined relative to the horizontal so that the end of the horizontal side of the bottom surface 93a becomes the lowest part of the oil storage section P. However, this disclosure is not limited to such a structure, and it is also possible to configure the bottom surface 93a to be inclined relative to the horizontal so that the middle part (e.g., the central part) of the bottom surface 93a in the horizontal direction becomes the lowest part of the oil storage section P. In this case, the bottom surface 93a includes a portion that is inclined relative to the horizontal and generally tends upward V1 as it tends towards the horizontal, and a portion that is inclined relative to the horizontal and generally tends downward V2 as it tends towards the horizontal. Alternatively, the bottom surface 93a may be configured to be horizontal (generally horizontal).

[0052] (2) In the above embodiment, the structure of the housing body 90 with two covers (91, 92) installed on both sides of the housing 9 along the axial direction L has been described as an example. However, this disclosure is not limited to such a structure. That is, the division of the housing 9 is arbitrary, and any component with a lower surface opening 90a on which the lower surface cover 93 is installed can become the housing body 90.

[0053] (3) The structure of the power transmission mechanism TA shown in the above embodiment is an example, and the structure of the power transmission mechanism TA can be appropriately modified. For example, it can also be configured such that the power transmission mechanism TA does not have one or both of the reversing gear mechanism 3 and the differential gear mechanism 4. Alternatively, it can be configured such that the power transmission mechanism TA has a planetary gear mechanism (e.g., a planetary gear type reduction mechanism) for transmitting power between the rotor 11 and the differential gear mechanism 4, and the power transmission mechanism TA transmits power between the rotor 11 and an output component 40 (i.e., a wheel W). In addition, the power transmission mechanism TA may also include engaging elements such as a clutch and a brake.

[0054] (4) In the above embodiments, the structure of the vehicle drive unit 10 is described as being used as a drive unit for an electric vehicle. However, this disclosure is not limited to such a structure; for example, the technology of this disclosure can also be applied to a drive unit for a hybrid vehicle.

[0055] (5) In the above embodiment, the structure of the output component 40 is described as an example, in which the component that rotates integrally with the pair of differential side gears 45 of the differential gear mechanism 4 is the output component 40. However, this disclosure is not limited to such a structure. For example, the drive shaft DS in the above embodiment may also be an "output component".

[0056] (6) Furthermore, the structures disclosed in the above embodiments can be combined with structures disclosed in other embodiments (including combinations of embodiments described as other embodiments) as long as they do not create contradictions. Regarding other structures, the embodiments disclosed in this specification are merely illustrative in all respects. Therefore, various changes can be appropriately made without departing from the spirit of this disclosure.

[0057] [Summary of this implementation method]

[0058] The following is a summary of the embodiments of the vehicle drive system described above.

[0059] The vehicle drive unit 10 includes: a rotary motor 1 having a rotor 11; an output component 40 drivenly connected to a wheel W; a power transmission mechanism TA for transmitting power between the rotor 11 and the output component 40; a housing 9 housing the rotary motor 1 and the power transmission mechanism TA; and an oil pump OP for drawing in and discharging oil accumulated in an oil reservoir P at the lower part of the housing 9 through an intake port 96. The housing 9 includes: a housing body 90 having a lower surface opening 90a opening downwards to a V2; and a lower surface cover 93 mounted on the housing body 90 to close the lower surface opening 90a and forming at least a portion of the oil reservoir P. The lower surface cover 93 includes: the intake port 96 opening into the oil reservoir P; and a pump mounting portion 94 formed in the portion that forms the inside of the housing 9. The oil pump OP is mounted on the pump mounting portion 94 and connected to the intake port 96 via an oil passage formed in the lower surface cover 93.

[0060] According to this structure, the oil pump OP is installed in the portion of the lower surface cover 93 that forms the inner side of the housing 9, thus making it easy to immerse at least a portion of the oil pump OP in the oil stored in the oil reservoir P. Therefore, even if the oil level OL in the oil reservoir P is set low, the oil pump OP can be properly lubricated by immersing at least a portion of the oil pump OP in the oil. As the amount of oil in the housing 9 decreases, the oil level OL in the oil reservoir P decreases, but according to this structure, as described above, even if the oil level OL in the oil reservoir P is set low, the oil pump OP can be properly lubricated. Therefore, the oil pump OP can be properly lubricated while the amount of oil in the housing 9 is kept low.

[0061] Furthermore, according to this structure, the oil pump OP is connected to the suction port 96 via an oil passage formed on the lower surface cover 93, thus making it easier to shorten the oil passage from the suction port 96 to the oil pump OP. Therefore, according to this structure, it also has the advantage of easily reducing the suction resistance of oil based on the oil pump OP.

[0062] Preferably, the lower surface cover 93 has a filter screen mounting portion 95 formed on the inner side of the housing 9, the filter screen ST for filtering oil is mounted on the filter screen mounting portion 95, at least a portion of the oil passage 71 connecting the suction port 96 to the filter screen ST and at least a portion of the oil passages 72 and 73 connecting the filter screen ST to the oil pump OP are formed on the lower surface cover 93.

[0063] According to this structure, the filter screen ST is installed on the lower surface cover 93, and the oil passage formed in the lower surface cover 93 allows for connection between the suction port 96 and the filter screen ST, as well as connection between the filter screen ST and the oil pump OP. Therefore, the oil passage from the suction port 96 to the oil pump OP is shortened, making it easier to reduce the oil suction resistance.

[0064] Furthermore, preferably, the upper surface V1 of the lower surface cover 93, which is the inner side of the housing 9, i.e., the bottom surface 93a of the cover, is arranged at an inclination relative to the horizontal, and the pump mounting part 94 is arranged on the side that is lower than the middle position H2 in the vertical direction V of the bottom surface 93a.

[0065] According to this structure, the oil pump OP is positioned at a relatively low position on the bottom surface 93a of the cover, making it easier to immerse at least a portion of the oil pump OP in the oil stored in the oil reservoir P. Therefore, lubrication of the oil pump OP can be easily performed.

[0066] In addition, preferably, a discharge oil passage 74 connected to the discharge port 52 of the oil pump OP is formed on the lower surface cover 93, and a connecting part 97 is provided at the end of the discharge oil passage 74. The connecting part 97 is connected to the housing body side oil passage 76 formed on the housing body 90 when the lower surface cover 93 is installed on the housing body 90.

[0067] According to this structure, in the configuration where the oil pump OP is mounted on the lower surface cover 93, the oil discharged from the oil pump OP can be appropriately supplied to the oil passage 76 on the housing body side.

[0068] The vehicle drive device disclosed herein only needs to be able to achieve at least one of the aforementioned effects.

[0069] Explanation of reference numerals in the attached figures

[0070] 1… Rotary motor; 9… Housing; 10… Vehicle drive unit; 11… Rotor; 40… Output component; 52… Discharge port; 71… First oil passage (oil passage connecting the intake to the filter); 72… Second oil passage (oil passage connecting the filter to the oil pump); 73… Third oil passage (oil passage connecting the filter to the oil pump); 74… Discharge oil passage; 76… Housing body side oil passage; 90… Housing body; 90a… Lower surface opening; 93… Lower surface cover; 93a… Cover bottom; 94… Pump mounting part; 95… Filter mounting part; 96… Intake; 97… Connection part; H2… Middle position; OP… Oil pump; P… Oil storage part; ST… Filter; TA… Power transmission mechanism; V… Up and down direction; V1… Upper side; V2… Lower side; W… Wheel.

Claims

1. A vehicle drive unit comprising: a rotary motor having a rotor; an output component drivingly connected to a wheel; a power transmission mechanism for transmitting power between the rotor and the output component; a housing housing the rotary motor and the power transmission mechanism; and an oil pump for drawing in and discharging oil accumulated in an oil reservoir at the lower part of the housing through an intake port, wherein... The housing comprises: a housing body having a lower surface opening facing downward; and a lower surface cover, which is mounted on the housing body to close the lower surface opening and forms at least a portion of the oil storage portion. The lower surface cover includes: the suction port, which opens into the oil storage section; and a pump mounting section, which is formed on the portion that becomes the inner side of the housing. The oil pump is installed in the pump mounting section and is connected to the suction port via an oil passage formed in the lower surface cover.

2. The vehicle drive unit according to claim 1, wherein, The lower surface cover has a filter mounting portion formed on the inner side of the housing. The filter screen for filtering oil is installed in the filter screen mounting part. At least a portion of the oil passage connecting the intake port to the filter screen and at least a portion of the oil passage connecting the filter screen to the oil pump are formed on the lower surface cover.

3. The vehicle drive unit according to claim 1 or 2, wherein, The upper-facing surface of the lower surface cover, which forms the inner side of the housing, i.e., the bottom surface of the cover, is arranged at an angle relative to the horizontal. The pump mounting part is positioned on one side that is lower than the middle position in the vertical direction of the bottom surface of the cover.

4. The vehicle drive unit according to claim 1 or 2, wherein, A discharge oil passage connected to the discharge port of the oil pump is formed on the lower surface cover. A connecting part is provided at the end of the discharge oil passage. When the lower surface cover is installed on the housing body, the connecting part is connected to the housing body side oil passage formed on the housing body.

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