Vehicle drive device

Abstract

In the vehicle drive device (10) of the present invention, a first shaft (A1) serving as the rotation axis of the input component is disposed on an upper side (V1) than a second shaft (A2) serving as the rotation axis of the reversing gear mechanism and a third shaft (A3) serving as the rotation axis of the output component. The housing (9) includes: a first oil passage (71) that supplies oil from an oil supply source to a first bearing that supports the input component for rotation; a second oil passage (72) that branches off from the first oil passage (71) and supplies oil to a second bearing that supports the reversing gear mechanism for rotation; and a third oil passage (73) that branches off from the first oil passage (71) and supplies oil to a third bearing that supports the output component for rotation.

Description

Technical Field

[0001] This invention relates to a drive system for vehicles. Background Technology

[0002] Japanese Patent Application Publication No. 2022-44049 discloses a vehicle drive unit (100) with a three-axis structure in which a rotary motor (1), a reduction gear (4), and an output component (6) are respectively arranged on different axes (the reference numerals in brackets in the background section are reference numerals of the document to be referenced). In this vehicle drive unit (100), when mounted on a vehicle (200), the shaft (third shaft (C3)) where the reduction gear (4) is arranged and the shaft (second shaft (C2)) where the output component (6) is arranged at the same height in the vertical direction (V). In addition, the shaft (first shaft (C1)) where the rotary motor (1) is arranged above the shaft (C3) where the reduction gear (4) is arranged in the vertical direction (V) in a manner that is aligned with the shaft (C3) in the vertical direction (V).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2022-44049

[0004] These shafts support rotating components via bearings, etc., allowing for free rotation. Therefore, in most cases, each bearing, etc., is housed within a housing of the vehicle's drive unit for oil lubrication. In most cases, oil is supplied from the top of the housing, flowing downwards to an oil reservoir while lubricating multiple lubrication points. The oil path is preferably configured to supply an appropriate amount of oil to each lubrication point and to appropriately recover frictional heat through heat exchange, thereby suppressing overheating of the lubrication points.

[0005] In view of the above background, in a vehicle drive unit having three rotating shafts that are parallel to each other, it is desirable to realize a structure that can appropriately supply oil to the lubrication points located on each shaft. Summary of the Invention

[0006] The vehicle drive unit according to the above-described situation includes: a rotary motor having a rotor; an input member connected to the rotor in a manner that rotates integrally with the rotor; an output member connected to a wheel drive; a reduction mechanism that reduces the rotation of the input member and transmits it to the output member; and a housing that houses the rotary motor, the input member, and the reduction mechanism, the reduction mechanism including: an input gear connected to the input member in a manner that rotates integrally with the input member; a reversing gear mechanism having a first reversing gear meshing with the input gear and a second reversing gear connected in a manner that rotates integrally with the first reversing gear; and an output gear meshing with the second reversing gear and connected to the output member. The components are integrated and rotated together with the output component. The input component is supported by a first bearing and is rotatable relative to the housing. The reversing gear mechanism is supported by a second bearing and is rotatable relative to the housing. The output component is supported by a third bearing and is rotatable relative to the housing. The first axis, which serves as the rotation axis of the input component, is positioned above the second axis, which serves as the rotation axis of the reversing gear mechanism, and the third axis, which serves as the rotation axis of the output component. The housing includes: a first oil passage that supplies oil from an oil supply source to the first bearing; a second oil passage that branches off from the first oil passage and supplies oil to the second bearing; and a third oil passage that branches off from the first oil passage and supplies oil to the third bearing.

[0007] According to this structure, the rotation of the input component is slowed down by the reduction mechanism and transmitted to the output component. Therefore, the rotational speed of the input component is higher than the rotational speed of the reversing gear mechanism and the output component. Consequently, the load on the first bearing supporting the input component is higher than the load on the second bearing supporting the reversing gear mechanism and the load on the third bearing supporting the output component. Furthermore, according to this structure, oil from the supply source is supplied to the first bearing through a first oil passage, and oil is distributed to the second and third bearings through second and third oil passages branching from the first oil passage. Therefore, more oil can be supplied to the first bearing with the greatest load, and the remaining oil supplied to the first bearing can be used for lubrication of the second and third bearings. That is, the amount of oil supplied from the supply unit can be reduced, and an appropriate amount of oil corresponding to the load can be supplied to each bearing. Thus, according to this structure, in a vehicle drive unit having three parallel rotating shafts, a structure that can appropriately supply oil to the lubrication points located on each shaft can be realized.

[0008] Further features and advantages of the drive system for vehicles will become apparent from the following description of illustrative and non-limiting embodiments illustrated with reference to the accompanying drawings. Attached Figure Description

[0009] Figure 1 It is a schematic exploded perspective view of a vehicle drive system.

[0010] Figure 2 This is a schematic diagram of a vehicle drive system.

[0011] Figure 3 This is a side view of the vehicle drive unit viewed from the first axial side.

[0012] Figure 4 It is a side view (front view) of the vehicle's drive unit viewed from the front-rear direction from the first side.

[0013] Figure 5 This is an enlarged side view of the vehicle drive unit viewed from the first axial side with the first cover open. Detailed Implementation

[0014] Hereinafter, embodiments of the drive system for vehicles will be described with reference to the accompanying drawings. Figure 1 This is a schematic exploded perspective view of the vehicle drive unit 10. Furthermore, several components, such as a portion of the cover component constituting the housing 9, are omitted from this exploded perspective view. Figure 2 This is a schematic diagram of the vehicle drive unit 10.

[0015] In the following description, "drive connection" refers to the state in which two rotating elements are connected in a manner capable of transmitting driving force. This includes the state in which the two rotating elements are connected in a manner that allows them to rotate as a whole, or the 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 multiple rotating elements in the planetary gear mechanism are connected to each other without being connected via other rotating elements.

[0016] like Figure 1 as well as Figure 2As shown, the vehicle drive unit 10 includes a rotary motor 1, an input component 2, a reversing gear mechanism 3, a differential gear mechanism 4, and a housing 9. The housing 9 houses the rotary motor 1, the input component 2, the reversing gear mechanism 3, and the 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 that are driven and connected to a pair of wheels W. Details will be described later; in this embodiment, the differential housing 42 of the differential gear mechanism 4 corresponds to the output components.

[0017] The vehicle drive unit 10 includes a reduction mechanism that slows down the rotation of the input component 2 and transmits it to the output component (differential housing 42). 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 (output gear). 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.

[0018] 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 (output component) in a manner that allows it to rotate integrally with the differential housing 42.

[0019] 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). Furthermore, 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 differential gear mechanism 4, including the differential housing 42 (output component), is 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 1As 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, or the third axis A3 may be positioned above the second axis A2 by a distance V1.

[0020] 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".

[0021] 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, and the upper part along the up-down direction V is referred to as the upper side V1, and the lower part 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, and 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".

[0022] 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 wound-excited synchronous rotating motor has a rotor structure in which an electromagnet using an excitation winding (rotor coil 13) replaces a permanent magnet as the excitation source. The excitation flux generated by the electromagnet can be transmitted from the excitation circuit controlled by the control device (all included in the circuit unit EU described later) via the contactless power supply unit 18 and the rectifier circuit 19 (see reference 18). Figure 2The excitation circuit adjusts the DC voltage supplied to the rotor coil 13 by the excitation current supplied to it. The DC voltage supplied by the DC power supply (not shown) is adjusted so that the set excitation current flows through the rotor coil 13. The power generated by the excitation circuit is transmitted in AC mode via the contactless power supply unit 18, and is converted into DC by the rectifier circuit 19 and supplied to the rotor coil 13.

[0023] Compared to permanent magnet synchronous motors (PMSMs), winding-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, their use 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.

[0024] like Figure 1 as well as Figure 2 As shown, the input component 2, input gear 21, reversing 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 allows it to rotate integrally with the rotor shaft 20. Furthermore, the input component 2 is supported by input bearing B2 (first bearing) and is rotatable relative to the housing 9. The input bearings B2 are arranged on both sides of the axial side L1, separated by the input gear 21. Distinguishing between the individual input bearings B2, the bearing arranged on the first axial side L1 relative to the input gear 21 is referred to as the first input bearing B21, and the bearing arranged on the second axial side L2 relative to the input gear 21 is referred to as the second input bearing B22.

[0025] The reversing gear mechanism 3 is supported by a reversing bearing B3 (second bearing) and is rotatable relative to the housing 9. Specifically, the reversing shaft 30, which connects the first reversing gear 31 and the second reversing gear 32, is supported by reversing bearings B3 located at two points along the axial direction L and is rotatable relative to the housing 9. The first reversing gear 31 is located on the first axial side L1 relative to the second reversing gear 32. The reversing shaft 30 is supported by the first reversing bearing B31 located on the first axial side L1 above the first reversing gear 31 and the second reversing bearing B32 located on the second axial side L2 above the second reversing gear 32 and is rotatable relative to the housing 9.

[0026] In this embodiment, the diameter of the first reverse gear 31 meshing with the input gear 21 is larger than the diameter of the input gear 21. Therefore, the rotational speed is reduced from the input component 2 and power is transmitted to the reverse shaft 30. Consequently, the frictional force at the bearing of the input bearing B2 is greater than the frictional force at the bearing of the reverse bearing B3, and there is a tendency for the heat generated by friction to also increase.

[0027] The differential gear mechanism 4 is supported by differential bearing B4 and is rotatable relative to the housing 9. Specifically, the differential housing 42 is rotatably supported on the housing 9 by a first differential bearing B41 disposed on the first axial side L1 relative to the differential housing 42 and a second differential bearing B42 disposed on the second axial side L2 relative to the differential housing 42. In this embodiment, the diameter of the differential input gear 41 meshing with the second reverse gear 32 is larger than the diameter of the second reverse gear 32. As a result, the rotational speed is further reduced compared to the reverse shaft 30, and power is transmitted to the differential housing 42, which rotates integrally with the differential input gear 41. Therefore, the frictional force at the bearing is greater than that of the differential bearing B4, and there is a tendency for the heat generated by friction to also be greater.

[0028] 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 differential pinion shafts 43 fixed to and rotating integrally with the differential housing 42. Multiple differential pinion shafts 43 are arranged radially (e.g., in a cross shape) along a radial direction R based on a third axis A3, and the plurality of differential pinions 44 are also arranged at intervals along the radial direction R. The pair of differential side gears 45 mesh with the plurality of differential pinions. The differential side gears 45 are configured to rotate about the third axis A3. The first differential side gear 45 of the pair of differential side gears is arranged on a first axial side L1 relative to the differential pinion shaft 43, and the second differential side gear 45 is arranged on a second axial side L2 relative to the differential pinion shaft 43.

[0029] In this embodiment, the first differential gear 45 disposed on the first axial side L1 is connected to the first drive shaft DS, and the first drive shaft DS is connected to the first wheel W. Additionally, the second differential gear 45 disposed on the second axial side L2 is connected to the connecting shaft JS, the connecting shaft JS is connected to the second drive shaft DS, and the second drive shaft DS is connected to the second wheel W.

[0030] 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 double pinion type planetary gear mechanism, the component that rotates integrally with the gear ring is equivalent to the output component.

[0031] In this embodiment, an oil passage is provided in the housing 9 to allow oil to circulate, so that lubricating oil can be appropriately supplied to the input bearing B2, the reverse bearing B3, and the differential bearing B4. Details will be described later. The housing 9 includes: a first oil passage 71 that supplies oil from an oil supply source to the input bearing B2 (first bearing); a second oil passage 72 that branches off from the first oil passage 71 and supplies oil to the reverse bearing B3 (second bearing); and a third oil passage 73 that branches off from the first oil passage 71 and supplies oil to the differential bearing B4 (third bearing) (see reference). Figure 3 wait).

[0032] Furthermore, the location where the oil passage is formed is not limited to the outer wall portion that divides the outer and inner parts of the housing 9, but also includes the support wall portion formed inside the housing 9 to support rotating components (input component 2, reverse shaft 30, etc.). In addition, "the housing 9 has an oil passage" is not limited to the case where the oil passage is integrally formed on the components constituting the housing 9, such as the outer wall portion and support wall portion, but also includes the case where the oil passage formed by piping components, etc., is fixed to the housing 9.

[0033] The following also refers to Figure 3 as well as Figure 4 The structure of the housing 9 and the structure of the oil circuit are described. Figure 3 This is a side view of the vehicle drive unit 10 as viewed from the first axial side L1. Additionally, Figure 4 This is a side view (front view) of the vehicle drive unit 10 viewed from the first side X1 in the front-rear direction.

[0034] The housing 9 includes: a first receiving chamber E1, which houses a power transmission mechanism TA such as a rotary motor 1, an input component 2, an input gear 21, a reversing gear mechanism 3, and a differential gear mechanism 4; and a second receiving chamber E2, which is divided relative to the first receiving chamber E1 and houses a circuit unit EU including 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, a first cover 91, a second cover 92, and a third cover 93, which form the core of the first receiving chamber E1 and the second receiving chamber E2.

[0035] The housing body 90 includes a cylindrical portion with openings on both sides in the axial direction L, and a box-shaped portion with a sidewall portion forming a rectangular opening extending from the peripheral wall of the cylindrical portion in the forward-rear direction X (here, the second side X2 in the forward-rear direction). A 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 (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 4The third cover 93 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 93.

[0036] The circuit unit EU is housed in the second receiving chamber E2 of the housing 9. Therefore, the housing 9 also has a first connector CN1 for power wiring connected to a high-voltage DC power supply (not shown) with a rated voltage of 200 volts or higher. Additionally, the housing 9 also has a second connector CN2 for approximately 12-volt power wiring supplying drive power to the control devices in the circuit unit EU, and for signal wiring connecting to control devices located above the circuit unit EU, such as a vehicle control device (not shown) controlling the entire vehicle, and various sensors. 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 inverter, smoothing capacitor, etc., of the circuit unit EU, and a cooling water outlet Wo, which serves as the outlet for cooling water, are also provided in the housing 9. Components mounted on the housing 9 (e.g., an oil cooler OC) are also present.

[0037] In this embodiment, such as Figure 3 As shown, a first oil passage 71, a second oil passage 72, and a third oil passage 73 are formed in the first cover 91. Figure 1 as well as Figure 3 As shown, the first cover 91 has a protrusion 99 that extends along the first cover 91 and protrudes from the outer surface 91a (the surface on the axial first side L1) of the first cover 91 along the axial direction L towards the outer side (axial first side L1) of the housing 9. A first oil passage 71, a second oil passage 72, and a third oil passage 73 are formed in this protrusion 99. Furthermore, in this embodiment, the case where the protrusion 99 protrudes from the outer surface 91a of the first cover 91 along the axial direction L towards the outer side of the housing 9 is illustrated; however, the protrusion 99 may also be formed to protrude from the inner surface 91b of the first cover 91 along the axial direction L towards the inner side (axial second side L2) of the housing 9.

[0038] Such a protrusion 99 can be shared with a reinforcing rib that strengthens the first cover 91 against the axial L load acting on the first cover 91 from the power transmission mechanism TA. In addition, compared with the structure in which a reinforcing rib is provided on the first cover 91, the construction of the first cover 91 is simplified and the increase in weight is also easier to suppress.

[0039] Of course, regardless of such reinforcing ribs, it does not preclude the structure of additionally providing a first oil passage 71, a second oil passage 72, and a third oil passage 73 within the housing 9.

[0040] like Figure 3 As shown, the first oil passage 71 is configured to supply oil from an oil supply source to an input bearing B2 disposed on a first shaft A1. A second oil passage 72 and a third oil passage 73 branch off from the first oil passage 71. The second oil passage 72, branching off from the first oil passage 71, is configured to supply oil to a reversing bearing B3 disposed on a second shaft A2 located V2 below the first shaft A1. Similarly, the third oil passage 73, branching off from the first oil passage 71, is configured to supply oil to a differential bearing B4 disposed on a third shaft A3 located V2 below the first shaft A1. The remaining oil from the oil supplied to the first oil passage 71 that is supplied to the input bearing B2 is distributed to the second oil passage 72 and the third oil passage 73.

[0041] As described above, in this embodiment, the first oil passage 71, the second oil passage 72, and the third oil passage 73 are formed on the first cover 91 disposed on the first axial side L1. Preferably, oil is supplied from the first oil passage 71 to the first input bearing B21, for example, oil is supplied to the second input bearing B22 via an oil passage (not shown) formed along the axial direction L on the radially inner side R1 of the input member 2.

[0042] In this embodiment, the protrusion 99, where the second oil passage 72 is formed, extends to a lower side V2 than the second shaft A2. Oil supplied from the first oil passage 71 to the second oil passage 72 is supplied to the first reverse bearing B31 at a position in the vertical direction V corresponding to the reverse bearing B3 (e.g., a position that at least partially overlaps with the reverse bearing B3 when viewed axially), through an oil supply hole 72h formed in the middle of the protrusion 99. Similar to the input bearing B2, oil is preferably further supplied to the second reverse bearing B32 via, for example, an oil passage (not shown) formed along the axial direction L on the radially inner side R1 of the reverse shaft 30.

[0043] Oil flowing in the second oil passage 72 and supplied to the oil supply hole 72h, while remaining oil, flows in the oil passage formed in the protrusion 99 and is released into the housing 9. Here, the oil passage downstream of the oil supply hole 72h is referred to as the fourth oil passage 74. The oil released into the housing 9 flows downward toward the V2 along the inner wall of the housing 9. A storage section P (see reference) is formed at the bottom of the housing 9. Figure 4 The oil return port 77 is connected. An enlarged side view of the vehicle drive unit 10 viewed from the first axial side L1 with the first cover 91 open. Figure 5 As shown, oil released into the housing 9 through the fourth oil passage 74 is supplied to the oil reservoir P through the oil return hole 77. The fourth oil passage 74 can be considered as the oil passage that supplies residual oil from the second oil passage 72, which is supplied to the reverse bearing B3, to the oil reservoir P. Furthermore, oil lubricated from the input bearing B2 and the reverse bearing B3 also falls into the housing 9. This oil is also supplied to the oil reservoir P through the oil return hole 77.

[0044] In this embodiment, an oil pump (not shown) is disposed within the housing 9 to draw in and discharge oil stored in the oil storage section P. The oil discharged from the oil pump is supplied to the first oil passage 71. Therefore, the oil pump is equivalent to a source of oil supply to the first oil passage 71. Furthermore, not limited to the case of directly supplying oil from the oil pump to the first oil passage 71, a collection tank that temporarily stores oil discharged from the oil pump and oil splashed by the rotating components of the power transmission mechanism TA (e.g., differential input gear 41) can also serve as a source of oil supply to the first oil passage 71.

[0045] Similar to the first oil passage 71, the third oil passage 73 supplies oil to the first differential bearing B41 disposed on the first axial side L1. Preferably, oil is supplied from an oil passage (not shown) that is connected to the third oil passage 73 and formed along the axial direction L, and is different from the third oil passage 73, to the second differential bearing B42 disposed on the opposite side of the axial direction L2, separated by the differential housing 42.

[0046] The differential gear mechanism 4 of this embodiment is configured as described above to house multiple bevel gears inside the differential housing 42. Preferably, the oil remaining after being supplied from the third oil passage 73 to the differential bearing B4 is supplied to lubrication-requiring parts such as the differential pinion shaft 43, differential pinion 44, and differential side gear 45 housed inside the differential housing 42. That is, preferably, the third oil passage 73 is connected to a fifth oil passage 75 that supplies oil to such lubrication-requiring parts. The fifth oil passage 75 can be described as an oil passage that supplies the oil remaining after being supplied from the third oil passage 73 to the differential bearing B4 to lubrication-requiring parts other than the input bearing B2, the reverse bearing B3, and the differential bearing B4.

[0047] Furthermore, in this embodiment, the flow path cross-sectional areas of the first oil passage 71, the second oil passage 72, and the third oil passage 73 are different. Specifically, the flow path cross-sectional area of ​​the first oil passage 71 is larger than the flow path cross-sectional areas of the second oil passage 72 and the third oil passage 73, and the flow path cross-sectional area of ​​the second oil passage 72 is larger than the flow path cross-sectional area of ​​the third oil passage 73. Alternatively, for example, it is preferable that the flow path cross-sectional area of ​​the first oil passage 71 is larger than the sum of the flow path cross-sectional areas of the second oil passage 72 and the third oil passage 73. Moreover, since the flow path cross-sectional area is related to the ease of oil flow, when the flow path cross-sectional area varies depending on the location within the flow path of each oil passage, the flow path cross-sectional area of ​​the narrowest location in the overall flow path of each oil passage is compared.

[0048] like Figure 3As shown, relative to the first oil passage 71, the second oil passage 72 and the third oil passage 73 are arranged on the lower side V2. Oil flows downwards in the oil passages due to gravity. Therefore, if the cross-sectional area of ​​the second oil passage 72 and the third oil passage 73, which branch from the first oil passage 71, is larger than the cross-sectional area of ​​the first oil passage 71, it may be impossible to supply sufficient oil from the first oil passage 71 to the input bearing B2. More preferably, if the cross-sectional areas of the second oil passage 72 and the third oil passage 73 are smaller than the cross-sectional area of ​​the first oil passage 71, and the sum of the cross-sectional areas of the second oil passage 72 and the third oil passage 73 is smaller than the cross-sectional area of ​​the first oil passage 71, then it is easier to supply sufficient oil from the first oil passage 71 to the input bearing B2.

[0049] However, in existing vehicles that use an internal combustion engine as the driving force for the wheels (W), 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 use 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 thus increasing electricity consumption.

[0050] The vehicle drive unit 10 of this embodiment is configured such that by lubricating the bearings as described above, the heat absorbed from the bearings by the oil is effectively utilized as a heat source for heating, thereby improving the overall energy efficiency of the vehicle. Figure 4 As shown, the vehicle drive unit 10 includes an oil cooler OC (heat exchange unit), which performs heat exchange between oil supplied from the area formed in the lower part of the housing 9 where oil is stored, i.e., the oil reservoir P, and a heat medium. In this embodiment, an oil pump draws oil from the oil reservoir P and discharges it to the oil cooler OC. After heat exchange occurs between the heat medium and the oil in the oil cooler OC, the oil is supplied to the first oil passage 71.

[0051] 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 4 As shown, the oil cooler OC is installed outside the housing 9. Cooling water flows from... Figure 3 as well as Figure 4The cooling water supply port Wi shown is supplied to the oil cooler OC after cooling the circuit unit EU (inverter, smoothing capacitor, etc.) and the rotating motor 1 (e.g., stator 15). 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). Additionally, the cooling water can also exchange heat with the coolant in the battery cooler of the DC power supply. Since the performance of the DC power supply degrades at low temperatures, it is preferable to heat the DC power supply to a suitable temperature when the DC power supply temperature is low, such as during vehicle startup.

[0052] Furthermore, oil is also supplied to areas other than the first oil passage 71, the second oil passage 72, and the third oil passage 73. Therefore, the oil also absorbs heat from lubrication and cooling components other than the input bearing B2, the reverse bearing B3, and the differential bearing B4. For example, the rotor coil 13 and stator coil 17, which overheat due to current flow, are also cooled by the oil. Specifically, by applying oil to the rotor coil end 13e protruding from the axial L end of the rotor 11 and the stator coil end 17e protruding from the axial L end of the stator 15, the rotor coil 13 and stator coil 17 are cooled. According to this embodiment, heat can also be effectively recovered from the oil used to cool the rotor coil 13 and stator coil 17.

[0053] Furthermore, the "heat medium" that exchanges heat with the oil supplied from the oil storage unit P 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 unit P itself can also function as an oil cooler OC. In other words, the "heat exchange unit" is not limited to the case where heat exchange occurs between the oil supplied from the oil storage unit P, for example via an oil pump, and the heat medium; it can also be the case where heat exchange occurs between the oil accumulated in the oil storage unit P and the heat medium.

[0054] As described above, the cross-sectional area of ​​the first oil passage 71 is larger than that of the second oil passage 72 and the third oil passage 73, and the cross-sectional area of ​​the second oil passage 72 is larger than that of the third oil passage 73. Furthermore, the frictional force at the input bearing B2 is greater than that at the reverse bearing B3 and the differential bearing B4. This allows for the supply of more oil to the input bearing B2, which has high friction and is prone to generating significant heat, thus enabling appropriate heat recovery.

[0055] In the vehicle drive unit 10, the path of the oil used to lubricate and cool the power transmission mechanism TA is preferably configured to supply an appropriate amount of oil to each lubrication target part and to appropriately recover heat from the power transmission mechanism TA through heat exchange. According to this embodiment, in the vehicle drive unit 10 having three mutually parallel rotating shafts, a structure is realized that can appropriately supply oil to the lubrication target parts arranged on each shaft, and the heat recovered from the lubrication target parts can also be easily and effectively utilized.

[0056] [Summary of Implementation Methods]

[0057] The following is a brief summary of the vehicle drive unit 10 described above.

[0058] As one embodiment, the vehicle drive unit 10 includes: a rotary motor 1 having a rotor 11; an input component 2 connected to the rotor 11 in a manner that rotates integrally with the rotor 11; an output component 42 driven by a wheel W; reduction mechanisms 21, 3, and 41 that reduce the rotation of the input component 2 and transmit it to the output component 42; and a housing 9 that houses the rotary motor 1, the input component 2, and the reduction mechanisms 21, 3, and 41, wherein the reduction mechanisms 21, 3, and 41 include: an input gear 21 connected to the input component 2 in a manner that rotates integrally with the input component 2; a reversing gear mechanism 3 having a first reversing gear 31 meshing with the input gear 21 and a second reversing gear 32 connected in a manner that rotates integrally with the first reversing gear 31; and an output gear 41 meshing with the second reversing gear 32. Furthermore, the input component 2 is rotatably connected to the output component 42 in a manner that is integral with the output component 42. The input component 2 is supported by the first bearing B2 and is rotatable relative to the housing 9. The reversing gear mechanism 3 is supported by the second bearing B3 and is rotatable relative to the housing 9. The output component 42 is supported by the third bearing B4 and is rotatable relative to the housing 9. The first axis A1, which serves as the rotation axis of the input component 2, is positioned above the second axis A2, which serves as the rotation axis of the reversing gear mechanism 3, and the third axis A3, which serves as the rotation axis of the output component 42, by a distance V1. The housing 9 includes: a first oil passage 71 that supplies oil from an oil supply source to the first bearing B2; a second oil passage 72 that branches off from the first oil passage 71 and supplies oil to the second bearing B3; and a third oil passage 73 that branches off from the first oil passage 71 and supplies oil to the third bearing B4.

[0059] According to this structure, the rotation of the input component 2 is reduced and transmitted to the output component 42 by the reduction mechanisms 21, 3, and 41. Therefore, the rotational speed of the input component 2 is higher than the rotational speed of the reverse gear mechanism 3 and the rotational speed of the output component 42. Consequently, the load on the first bearing B2 supporting the input component 2 is higher than the load on the second bearing B3 supporting the reverse gear mechanism 3 and the load on the third bearing B4 supporting the output component 42. Furthermore, according to this structure, oil from the supply source is supplied to the first bearing B2 via the first oil passage 71, and the oil is distributed to the second bearing B3 and the third bearing B4 via the second oil passage 72 and the third oil passage 73 branching from the first oil passage 71. Therefore, more oil can be supplied to the first bearing B2, which bears the greatest load, and the remaining oil supplied to the first bearing B2 can be used for the lubrication of the second bearing B3 and the third bearing B4. That is, the amount of oil supplied from the supply unit can be reduced, and an appropriate amount of oil corresponding to the load can be supplied to each bearing. Thus, according to this structure, in a vehicle drive unit 10 having three rotating shafts that are parallel to each other, it is possible to achieve a structure that can appropriately supply oil to the lubrication points located on each shaft.

[0060] Here, it is preferable that the flow path cross-sectional area of ​​the first oil passage 71 is larger than the flow path cross-sectional area of ​​the second oil passage 72 and the third oil passage 73, and the flow path cross-sectional area of ​​the second oil passage 72 is larger than the flow path cross-sectional area of ​​the third oil passage 73.

[0061] According to this structure, the most oil can be supplied to the first bearing B2, which has the highest load, and more oil can be supplied to the second bearing B3, which has the second highest load, than to the third bearing B4. Therefore, it is possible to supply each bearing with an appropriate amount of oil corresponding to its load.

[0062] Furthermore, preferably, the vehicle drive unit 10 also includes: an oil reservoir P, which is an area formed in the lower part of the housing 9 for storing oil; and a heat exchange unit OC, which performs heat exchange between the oil stored in the oil reservoir P or the oil supplied from the oil reservoir P and a heat medium. The housing 9 includes: a fourth oil passage 74, which supplies the oil remaining from the supply from the second oil passage 72 to the second bearing B3 to the oil reservoir P; and a fifth oil passage 75, which supplies the oil remaining from the supply from the third oil passage 73 to the third bearing B4 to parts that require lubrication other than the first bearing B2, the second bearing B3, and the third bearing B4.

[0063] According to this structure, oil that has become hot due to passing through bearings with a load greater than that of the third bearing B4, namely the first bearing B2 and the second bearing B3, can be quickly returned to the oil storage section P. Therefore, the heat of the oil can be effectively recovered in the heat exchange section OC before the oil temperature drops.

[0064] Preferably, the vehicle drive unit 10 takes the direction along the first axis B2 as the axial direction, and the housing 9 has a cover 91 that covers the housing E1 containing the rotary motor 1, the input component 2, and the reduction mechanisms 21, 3, and 41 from one side L1 of the axial direction L. The first oil passage 71, the second oil passage 72, and the third oil passage 73 are formed in the protrusion 99, which is formed to extend along the cover 91 and protrude from the inner surface 91b or the outer surface 91a of the cover 91 toward the axial direction L.

[0065] According to this structure, the protrusions 99 formed on the cover 91 to form the first oil passage 71, the second oil passage 72, and the third oil passage 73 can function to strengthen the cover 91 against the axial loads acting on it by the power transmission mechanism TA from the input member 2 to the output member 42. Therefore, according to this structure, the first oil passage 71, the second oil passage 72, and the third oil passage 73 can be easily formed on the cover 91, and the increase in the weight of the cover 91 is suppressed to ensure strength.

[0066] Explanation of reference numerals in the attached figures

[0067] 1… Rotary motor; 2… Input component; 3… Reversing gear mechanism (reduction mechanism); 9… Housing; 10… Vehicle drive unit; 11… Rotor; 21… Input gear (reduction mechanism); 31… First reversing gear; 32… Second reversing gear; 41… Differential input gear (output gear, reduction mechanism); 42… Differential housing (output component); 71… First oil passage; 72… Second oil passage; 73… Third oil passage; 74… Fourth oil passage; 75… Fifth oil passage; 91… First cover (cover section); 91a …Outer surface; 91b…Inner surface; 99…Protrusion; A1…First shaft (first axis); A2…Second shaft (second axis); A3…Third shaft (third axis); B2…Input bearing (first bearing); B3…Reverse bearing (second bearing); B4…Differential bearing (third bearing); DS…Drive shaft; E1…First housing chamber (housing chamber for rotary motor, input component, and reduction mechanism); L…Axial direction; OC…Oil cooler (heat exchange section); P…Oil storage section; V1…Upper side; W…Wheel.

Claims

1. A drive unit for a vehicle, comprising: A rotating electric motor, which has a rotor; An input component is connected to the rotor in a manner that allows it to rotate integrally with the rotor; Output components, which are connected to the wheel drive; A speed reduction mechanism that reduces the rotational speed of the input component and transmits it to the output component; and A housing that houses the rotary motor, the input component, and the reduction gear mechanism. The deceleration mechanism includes: An input gear is connected to the input component in a manner that allows it to rotate integrally with the input component; A reversing gear mechanism comprising a first reversing gear meshing with the input gear, and a second reversing gear connected to the first reversing gear in a manner that allows it to rotate integrally with it; and An output gear, which meshes with the second reverse gear and is connected to the output component in a manner that allows it to rotate integrally with the output component. The input component is supported by a first bearing and is rotatable relative to the housing. The reversing gear mechanism is supported by a second bearing and is rotatable relative to the housing. The output component is supported by a third bearing and is rotatable relative to the housing. The first axis, which serves as the rotation axis of the input component, is positioned above the second axis, which serves as the rotation axis of the reversing gear mechanism, and the third axis, which serves as the rotation axis of the output component. The housing includes: a first oil passage for supplying oil from an oil supply source to the first bearing; a second oil passage branching from the first oil passage to supply oil to the second bearing; and a third oil passage branching from the first oil passage to supply oil to the third bearing.

2. The vehicle drive unit according to claim 1, wherein, The cross-sectional area of ​​the first oil passage is larger than that of the second oil passage and the third oil passage. The cross-sectional area of ​​the second oil passage is larger than that of the third oil passage.

3. The vehicle drive unit according to claim 1 or 2, wherein, The vehicle drive unit also includes: An oil storage section, which is an area formed in the lower part of the casing for accumulating oil; and A heat exchange section that performs heat exchange between the oil stored in or supplied from the oil storage section and a heat medium. The housing includes: a fourth oil passage that supplies oil remaining from the second oil passage supplied to the second bearing to the oil reservoir; and a fifth oil passage that supplies oil remaining from the third oil passage supplied to the third bearing to the first bearing, the second bearing, and other parts requiring lubrication.

4. The vehicle drive unit according to claim 1 or 2, wherein, The direction along the first axis is taken as the axial direction. The housing includes a cover that covers, from one side of the axial direction, a housing chamber that accommodates the rotary motor, the input component, and the reduction mechanism. The first oil passage, the second oil passage, and the third oil passage are formed in the protrusion, which is formed to extend along the cover and protrude from the inner or outer surface of the cover towards the axial direction.

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