Vehicle drive systems

Abstract

Disclosed is a vehicle drive device comprising: a rotary electric machine; a transmission mechanism that transmits drive force from the rotary electric machine to a wheel via a shaft member; a case that accommodates the rotary electric machine, the transmission mechanism, and the shaft member; and a flow channel forming member that is accommodated in the case or formed as a portion of the case, and forms a coolant flow channel around the rotary electric machine, there being formed inside the case a first accommodating chamber inside which accumulates oil that can be scooped up by rotation of gears in the transmission mechanism, a second accommodating chamber that accommodates the rotary electric machine, a first communicating path which is provided in a partition wall, one end of the first communicating path being communicated with a space on one axial end side of the second accommodating chamber and the other end being communicated with the first accommodating chamber, and a second communicating path, one end of which is communicated with a space on the other axial end side of the second accommodating chamber and the other end being communicated with the first accommodating chamber and provided below the shaft member.

Description

Technical Field

[0001] The present disclosure relates to a drive device for a vehicle.

Background Art

[0002] There is known a technique including a case that forms a motor housing chamber for housing a rotating electric machine and a gear housing chamber for housing a transmission mechanism, and scraping up oil accumulated in the lower part of the gear housing chamber by the rotation of gears of the transmission mechanism and supplying it to various bearings of the transmission mechanism.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the prior art as described above, it is difficult to efficiently return the oil scraped up by the rotation of the gears of the transmission mechanism to the lower part of the gear housing chamber after using the oil for lubricating the lubrication target.

[0005] Therefore, in one aspect, an object of the present disclosure is to efficiently return the oil scraped up by the rotation of the gears of the transmission mechanism to a space part that can be scraped up by the rotation of the gears after using the oil for lubricating the lubrication target.

Means for Solving the Problems

[0006] In one aspect, a rotating electric machine, a transmission mechanism that transmits the driving force from the rotating electric machine to a wheel, a case, a flow path forming member that is housed in the case or formed as a part of the case and forms a refrigerant flow path around the rotating electric machine, are provided, Inside the case, A first containment chamber in which oil that can be scooped up by the rotation of the gears of the transmission mechanism accumulates, A second housing chamber for housing the aforementioned rotating electric machine, A first connecting passage is provided in the partition wall between the first and second storage chambers in the case in the axial direction, The second connecting passageway, Formed, The aforementioned transmission mechanism transmits driving force to the wheel via the shaft member, The flow path forming member separates the movement of oil between the space on one axial end of the rotating electric machine that is connected to the transmission mechanism and the space on the other axial end of the rotating electric machine. The first connecting passage has one end that communicates with the space on the axial side of the second containment chamber, and the other end that communicates with the first containment chamber. A vehicle drive device is provided in which the second connecting passage has one end communicating with the space on the other axial end side of the second housing chamber, the other end communicating with the first housing chamber, and is provided below the shaft member. [Effects of the Invention]

[0007] In one aspect, according to this disclosure, the oil scraped up by the rotation of the gears of the transmission mechanism can be efficiently returned to the space into which it can be scraped up by the rotation of the gears after it has been used to lubricate the object to be lubricated. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic top view diagram showing the mounting configuration of the vehicle's drive system. [Figure 2] This is a cross-sectional view of a vehicle drive system. [Figure 2A] This is a skeleton diagram showing a vehicle drive system. [Figure 3] This is a schematic side view showing the vehicle drive system according to this embodiment, as viewed from the A1 side. [Figure 4] This is a perspective view of the channel forming member. [Figure 5] This is an enlarged view of section Q6 in Figure 2. [Figure 6]This is a schematic side view showing the vehicle drive system according to this embodiment, as viewed from the A2 side. [Figure 7] This is a schematic perspective view of the vehicle drive system according to this embodiment, as seen from the A2 side. [Figure 8] This is an explanatory diagram of the return flow path of the vehicle drive system according to this embodiment. [Modes for carrying out the invention]

[0009] The following describes each embodiment in detail with reference to the attached drawings. Note that the dimensional ratios in the drawings are merely examples and are not exhaustive. Furthermore, some shapes and other details in the drawings may be exaggerated for illustrative purposes.

[0010] In the following explanation, the Y direction (see Figure 3, etc.) corresponds to the vertical direction of the vehicle drive unit 100 in its operating state, that is, the vertical direction when the vehicle drive unit 100 is positioned in its operating orientation. The Y1 side and Y2 side correspond to the upper and lower sides along the Y direction. Note that the vertical direction does not necessarily have to be parallel to the vertical direction; it is sufficient if it is predominantly composed of a vertical component. Furthermore, the direction of each component in the following explanation represents the direction when they are assembled to the vehicle drive unit 100. In addition, terms related to the dimensions, arrangement direction, arrangement position, etc., of each component are concepts that include differences due to errors (errors that are within the range that can be tolerated in manufacturing). The A direction (see Figure 2, etc.) corresponds to the axial direction, and in Figure 2, etc., the A1 side and A2 side along the A direction are defined. The X direction (see Figure 3, etc.) is a direction orthogonal to both the A direction and the Y direction, and in Figure 3, etc., the X1 side and X2 side along the X direction are defined.

[0011] In this specification, "driving connection" refers to a state in which two rotating elements are connected so as to be able to transmit a driving force (synonymous with torque), including a state in which the two rotating elements are connected so as to rotate integrally, or a state in which the two rotating elements are connected so as to be able to transmit a driving force via one or more transmission members. Such transmission members include various members that transmit rotation at the same speed or with speed change (for example, shafts, gear mechanisms, belts, chains, etc.). Note that the transmission members may include engagement devices (for example, friction engagement devices, meshing engagement devices, etc.) that selectively transmit rotation and driving force.

[0012] In addition, in this specification, "communication" refers to a state in which two spatial elements are in fluid communication with each other. That is, it refers to a state in which fluid can flow back and forth between two spatial elements. At this time, the two spatial elements may communicate directly or indirectly (that is, via other spatial elements).

[0013] In this specification, "rotating electrical machine" is used as a concept that includes any of a motor (electric motor), a generator (generator), and a motor-generator that performs the functions of both a motor and a generator as necessary. Further, in this specification, regarding the arrangement of two members, "overlapping in a specific direction view" means that when a virtual straight line parallel to the line-of-sight direction is moved in each direction orthogonal to the virtual straight line, there is at least a part of a region where the virtual straight line intersects both of the two members. Also, in this specification, regarding the arrangement of two members, "the arrangement regions in a specific direction overlap" means that at least a part of the arrangement region of one member in a specific direction is included in the arrangement region of the other member in the specific direction.

[0014] FIG. 1 is a schematic top view showing the mounting state of the vehicle drive device 100 in the vehicle VC. FIG. 2 is a cross-sectional view of the vehicle drive device 100. FIG. 2A is a skeleton view showing the vehicle drive device 100.

[0015] As schematically shown in Figure 2A, the vehicle drive unit 100 comprises a rotating electric machine 1, a pair of output members 6 that are driven and connected to a pair of wheels W (see Figure 1), and a transmission mechanism 3 that transmits driving force between the rotating electric machine 1 and the pair of output members 6. The vehicle drive unit 100 further comprises a case 2 that houses the rotating electric machine 1. The case 2 also houses the pair of output members 6 and the transmission mechanism 3. In a modified example, the case 2 may house only one of the pair of output members 6 (for example, the first output member 61). Furthermore, the vehicle drive unit 100 can be applied to any vehicle having a rotating electric machine 1, such as electric vehicles or hybrid vehicles, and the drive system can be any vehicle, such as front-wheel drive or rear-wheel drive. Also, the drive source may be only an engine (internal combustion engine).

[0016] One of a pair of output members 6, the first output member 61, is driven and connected to the first wheel W1, one of a pair of wheels W, and the other of the pair of output members 6, the second output member 62, is driven and connected to the second wheel W2, the other of the pair of wheels W. As shown in Figure 1, the vehicle VC on which the vehicle drive unit 100 is mounted includes a first drive shaft 63 that rotates integrally with the first wheel W1 and a second drive shaft 64 that rotates integrally with the second wheel W2. The first drive shaft 63 is connected to the first wheel W1, for example via a constant velocity joint, and the second drive shaft 64 is connected to the second wheel W2, for example via a constant velocity joint. The first output member 61 is connected to the first drive shaft 63 so as to rotate integrally with the first drive shaft 63, and the second output member 62 is connected to the second drive shaft 64 so as to rotate integrally with the second drive shaft 64. The first output member 61 may be in the form of an intermediate shaft. The first output member 61 is rotatably supported on the axial side A2 via bearing BR1 relative to the case 2, and on the axial side A1 via bearing BR2 relative to the case 2. In this embodiment, bearings BR1 and BR2 are ball bearings as an example, but other forms may also be used.

[0017] The vehicle drive unit 100 transmits the output torque of the rotating electric machine 1 to a pair of wheels W via a pair of output members 6, thereby driving the vehicle VC on which the vehicle drive unit 100 is mounted. In other words, the rotating electric machine 1 is the driving force source for the pair of wheels W. The pair of wheels W are a left and right pair of wheels on the vehicle VC (for example, a left and right pair of front wheels, or a left and right pair of rear wheels). The rotating electric machine 1 may be, for example, an AC rotating electric machine driven by a three-phase AC.

[0018] As shown in Figure 2, the rotating electric machine 1 and the pair of output members 6 are arranged on two parallel axes (specifically, a first axis C1 and a second axis C2). Specifically, the rotating electric machine 1 is positioned on the first axis C1, and the pair of output members 6 are positioned on a second axis C2, which is different from the first axis C1. The first axis C1 and the second axis C2 are axes (virtual axes) that are positioned parallel to each other. The transmission mechanism 3 is provided with an output gear (ring gear) 30 that is driven and connected to at least one of the pair of output members 6, coaxially with the pair of output members 6 (i.e., on the second axis C2).

[0019] The rotating electric machine 1 is, for example, an inner rotor type. In the rotating electric machine 1, a rotor 14 that can rotate around the first axis C1 is arranged radially inside the stator 11 (see Figure 2).

[0020] The transmission mechanism 3 includes a reduction mechanism 34 in the power transmission path between the rotating electric machine 1 and the output gear 30. The reduction mechanism 34 is optional and may include a reduction mechanism using a counter gear or a reduction mechanism using planetary gears. In this embodiment, as an example, the reduction mechanism 34 includes a planetary gear mechanism and is arranged coaxially with the rotating electric machine 1. The output gear (carrier) 342 of the reduction mechanism 34 meshes radially with the output gear 30 of the differential gear mechanism 5. Such a vehicle drive system 100 can have a compact configuration consisting of two shafts (first shaft C1 and second shaft C2). In a modified example, the vehicle drive system 100 may have three or more shafts.

[0021] In this embodiment, the reduction mechanism 34 is arranged coaxially with the rotating electric machine 1 (i.e., on the first axis C1) and is driven and connected to the rotating electric machine 1. In this embodiment, as an example, the rotor 14 of the rotating electric machine 1 rotates integrally with the input member 16 together with the sun gear 341 of the reduction mechanism 34.

[0022] Furthermore, the transmission mechanism 3 further includes a differential gear mechanism 5. The differential gear mechanism 5 distributes the driving force transmitted from the rotating electric machine 1 to a pair of output members 6. In the example shown in Figure 2, the differential gear mechanism 5 distributes the rotation of the output gear 30 to the first side gear 51 and the second side gear 52. The differential gear mechanism 5 may be arranged coaxially with the pair of output members 6 (i.e., on the second shaft C2). The differential gear mechanism 5 may be a bevel gear type differential gear mechanism, and the output gear 30 may be connected to the differential case portion 50 of the differential gear mechanism 5 so as to rotate integrally with the differential case portion 50.

[0023] Next, referring to Figure 3 and subsequent figures, the water-cooling structure of the rotating electric machine 1 according to this embodiment and its related components (such as the flow path forming member 90) will be described.

[0024] Figure 3 is a schematic side view of the vehicle drive unit 100 according to this embodiment. In Figure 3, the motor cover member 201 (see Figure 2) is omitted from the illustration so that the state inside the motor housing chamber S1 can be seen. Also in Figure 3, the inverter device 70 inside the inverter case 24 is schematically shown with a dotted line. Figure 4 is a perspective view of the flow path forming member 90.

[0025] The water-cooling structure of the rotating electric machine 1 according to this embodiment is a structure for cooling the rotating electric machine 1 with cooling water. The cooling water may be water containing, for example, LLC (Long Life Coolant), and may be circulated by a water pump (not shown). A heat dissipation part such as a radiator (not shown) may be provided in the cooling water circulation path. In addition to cooling the rotating electric machine 1, the cooling water may also be used to cool other components, such as an inverter (not shown) that is electrically connected to the rotating electric machine 1.

[0026] The water-cooling structure of the rotating electric machine 1 according to this embodiment includes a refrigerant supply unit 40, a refrigerant discharge unit 42, and a flow path forming member 90.

[0027] The refrigerant supply unit 40 communicates with the discharge side of, for example, a water pump (not shown) and supplies cooling water to the refrigerant flow path 300 formed by the flow path forming member 90.

[0028] The refrigerant discharge section 42 communicates with the suction side of, for example, a water pump (not shown), and supplies (discharges) cooling water from the refrigerant flow path 300 formed by the flow path forming member 90 to the water pump (not shown).

[0029] The refrigerant supply unit 40 and the refrigerant discharge unit 42 may be provided above and below the first output member 61, respectively. In this case, the space around the first output member 61 can be effectively utilized to accommodate the refrigerant supply unit 40 and the refrigerant discharge unit 42.

[0030] As shown in Figure 4, the flow path forming member 90 has a cylindrical shape with an inner circumferential surface radially opposite the outer circumferential surface of the rotating electric machine 1. The flow path forming member 90 forms a refrigerant flow path 300 around the rotating electric machine 1. In the example shown in Figure 4, the refrigerant flow path 300 has multiple flow path sections SC1 to SC4 in the circumferential direction, but the configuration of the refrigerant flow path 300 is arbitrary.

[0031] The flow path forming member 90 may be made of a material with good thermal conductivity, such as aluminum. In this embodiment, as an example, the flow path forming member 90 is fitted to the stator core 12 of the stator 11 by shrink fitting, for example. In other embodiments, the flow path forming member 90 may be integrally formed with the stator core 12 by casting or the like.

[0032] In this embodiment, the flow path forming member 90 is, as an example, in the form of an inner case fastened to the case 2, as shown in Figure 3. In this case, the flow path forming member 90 may have a plurality of fastening portions 500 on one axial end, as shown in Figure 3. The plurality of fastening portions 500 are fastened to the case 2 by bolts (not shown) (see bolt holes BT4). In a modified example, the flow path forming member 90 may be formed as part of the case 2.

[0033] The flow path forming member 90 is inserted into the cylindrical space of the case 2. At this time, the outer circumferential surface of the flow path forming member 90 faces radially with respect to the inner circumferential surface of the case 2 (the inner circumferential surface that defines the multiple fastening portions 500). Hereafter, the inner circumferential surface of the case 2 that surrounds the flow path forming member 90 in this manner will also be referred to as the "flow path forming surface 209 of the case 2" (see Figure 5). The inner diameter of the flow path forming surface 209 of the case 2 may be a constant value that is larger than the basic outer diameter of the stator core 12 by the basic thickness of the flow path forming member 90.

[0034] The flow path forming member 90 cooperates with the flow path forming surface 209 of the case 2 to form a refrigerant flow path 300. Specifically, the refrigerant flow path 300 is formed radially between the outer circumferential surface of the flow path forming member 90 and the flow path forming surface 209 of the case 2.

[0035] The refrigerant flow path 300 may extend circumferentially so that cooling water flows circumferentially throughout the entire circumferential direction. The refrigerant flow path 300 may also be formed so as to be radially opposite the outer circumferential surface of the stator core 12 over the entire axial direction of the stator core 12 of the rotating electric machine 1. The refrigerant flow path 300 is closed at both axial ends. For example, between the flow path forming member 90 and the flow path forming surface 209 of the case 2, a sealing member 97 (see Figure 5) may be provided over the entire circumferential direction at both axial ends of the flow path forming member 90.

[0036] Next, with reference to Figure 5 and subsequent figures, the oil passage structure of the vehicle drive unit 100 according to this embodiment and its related components will be described. Unless otherwise specified, the various oil passages in the oil passage structure described below are formed by case 2. In this specification, the various oil passages formed by case 2 include not only oil passages formed by case 2 alone, but also oil passages formed by a combination of case 2 and other components (components other than case 2). Furthermore, a housing chamber such as the output shaft housing chamber S3 also constitutes an oil passage.

[0037] Here, we will first explain the configuration of Case 2 with reference to Figure 2, etc., and then explain the oil passage structure with reference to Figure 5 and onward.

[0038] In this embodiment, case 2 includes a motor case section 21, a transmission mechanism case section 22, an output shaft case section 23, and an inverter case section 24 in an integrated form. Here, "integrated form" includes forms where the components are integrated with fastening members such as bolts, or forms where they are integrated by integral molding (for example, casting or aluminizing).

[0039] The motor case section 21 forms a motor housing chamber S1 for housing the rotating electric machine 1, the transmission mechanism case section 22 forms a transmission mechanism housing chamber S2 for housing the transmission mechanism 3, the output shaft case section 23 forms an output shaft housing chamber S3 for housing the first output member 61, and the inverter case section 24 forms an inverter housing chamber S4 for housing the inverter device 70. Note that when we say that the motor case section 21 forms the motor housing chamber S1, we mean that the wall section bordering the motor housing chamber S1 forms the motor case section 21. This also applies to the transmission mechanism housing chamber S2, the output shaft case section 23, and the inverter case section 24.

[0040] The motor case portion 21 has a cylindrical shape corresponding to the outer shape of the rotating electric machine 1. However, the motor case portion 21 does not need to have a completely closed cylindrical outer circumference. For example, the motor housing chamber S1 and the output shaft housing chamber S3 may be in communication, in which case a wall portion (partition wall portion) does not need to be formed on the side of the motor case portion 21 facing the output shaft housing chamber S3.

[0041] The transmission mechanism case 22 is located on the axial A2 side relative to the motor case 21 and the output shaft case 23. The output shaft case 23 is located on the X2 side in the X direction relative to the motor case 21. The inverter case 24 is located above the transmission mechanism case 22 and the output shaft case 23. Details of the inverter case 24 will be described later.

[0042] In this embodiment, since the output shaft case portion 23 is provided, the first output member 61 can be effectively protected from the external environment (e.g., flying stones) compared to the case where the first output member 61 is provided outside the case 2. In addition, the clearance that needs to be secured between the first output member 61 and surrounding parts can be reduced. However, in a modified example, the first output member 61 may be provided outside the case 2.

[0043] Case 2 may be formed by joining multiple components (case components and cover components). Therefore, one component forming Case 2 may form two or more case components from among the motor case component 21, the transmission mechanism case component 22, the output shaft case component 23, and the inverter case component 24.

[0044] Furthermore, the motor housing chamber S1, transmission mechanism housing chamber S2, output shaft housing chamber S3, and inverter housing chamber S4 formed by case 2 may be completely isolated from each other, partially connected, or shared in a manner without boundaries. For example, the motor housing chamber S1 and the output shaft housing chamber S3 may be shared in a manner without partitions separating them. In this case, the rotating electric machine 1 and the first output member 61 will be housed in a common housing chamber formed by case 2 (specifically, the motor housing chamber S1 and the output shaft housing chamber S3). Also, if the rotating electric machine 1 is oil-cooled, the motor housing chamber S1 and the inverter housing chamber S4 may be partitioned, but if the rotating electric machine 1 is completely water-cooled, the motor housing chamber S1 and the inverter housing chamber S4 do not need to be partitioned.

[0045] In the following description, Case 2 is assumed to be formed by joining together a case member 200, a motor cover member 201, a differential cover member 202, and an inverter cover member 203, as an example. The joining method may be fastening with bolts or the like.

[0046] The case member 200 may be formed from a single piece of material (for example, a single piece of material made by die-casting). In this case, the motor housing chamber S1 and the transmission mechanism housing chamber S2 may be separated by a single partition wall 26.

[0047] The case member 200 has an axial opening on the axial A1 side and an axial opening on the axial A2 side.

[0048] The motor cover member 201 is provided to cover the axial A1-side opening in the case member 200 (i.e., the axial A1-side opening of the motor housing chamber S1). The motor cover member 201 may be formed as a single piece. The motor cover member 201 may be joined to the axial A1-side end face (joint surface) of the case member 200. In this case, the joint surface (matting surface) 221 between the motor cover member 201 and the case member 200 may extend in a plane perpendicular to the axial direction.

[0049] The differential cover member 202 is provided to cover the axial A2-side opening in the case member 200 (i.e., the axial A2-side opening of the transmission mechanism housing chamber S2). The differential cover member 202 may be formed as a single piece. The differential cover member 202 may be joined to the axial A2-side end face (joint surface) of the case member 200. In this case, the joint surface (matting surface) 222 between the differential cover member 202 and the case member 200 may extend in a plane perpendicular to the axial direction.

[0050] The inverter cover member 203 is provided to cover the opening of the inverter housing chamber S4 in the case member 200. The inverter cover member 203 may be formed as a single piece.

[0051] The inverter device 70 may be in the form of a module and may be fixed to the wall forming the inverter case 24 by bolts or the like. The inverter device 70 includes a plurality of switching elements (power semiconductor elements, not shown) that constitute the inverter circuit, a control board (not shown) on which a control device for controlling the inverter circuit is mounted, and smoothing capacitors and the like.

[0052] Figure 5 is a cross-sectional view taken from a plane passing through the second axis C2 and the Y direction, and is an enlarged view of part Q6 in Figure 2 (a cross-sectional view passing through the output shaft housing chamber S3). Figure 6 is a schematic side view of the vehicle drive unit 100 according to this embodiment, viewed from the A2 side. Figure 7 is a schematic perspective view of the vehicle drive unit 100 according to this embodiment, viewed from the A2 side. Figure 8 is an explanatory diagram of the return passages 290 and 292 of the vehicle drive unit according to this embodiment. In Figures 6 and 7, the differential cover member 202 is omitted from the illustration so that the state inside the transmission mechanism housing chamber S2 can be seen. In Figure 8, a schematic cross-sectional view taken from a plane including the center line C20 and the X direction of the return passage 290 is shown, and the return passage 292, which is at a different height (Y direction position), is schematically shown with a dotted line along with its center line C21.

[0053] As described above, the transmission mechanism housing chamber S2 and the output shaft housing chamber S3 overlap the second shaft C2 in a top view and are adjacent in the axial direction. Furthermore, since the transmission mechanism housing chamber S2 extends in the X direction in a manner that accommodates the reduction mechanism 34 and the differential gear mechanism 5, the transmission mechanism housing chamber S2 and the output shaft housing chamber S3 extend in an L-shape in a top view. Hereinafter, the portion of the transmission mechanism housing chamber S2 that accommodates the reduction mechanism 34 will also be referred to as the "reduction mechanism housing chamber S21," and the portion that accommodates the differential gear mechanism 5 will also be referred to as the "differential gear housing chamber S22."

[0054] The output shaft case portion 23 extends around the second shaft C2 along the extending direction (i.e., axial direction) of the first output member 61. The output shaft case portion 23 may take the form of a peripheral wall portion that forms the space (output shaft housing chamber S3) around the first output member 61. In this case, the output shaft case portion 23 extends radially outward (towards the X direction X2) of the rotating electric machine 1 and may also form a part of the motor case portion 21.

[0055] In this embodiment, the output shaft housing chamber S3 communicates with the transmission mechanism housing chamber S2 (particularly the differential gear housing chamber S22) on its axial A2 side. Furthermore, objects to be lubricated by oil are placed on the axial A1 side of the output shaft housing chamber S3. That is, the axial A1 end of the output shaft housing chamber S3 communicates with the space S31 where the objects to be lubricated by oil are located. In this embodiment, the objects to be lubricated by oil include a bearing BR2 and an oil seal 700. The oil seal 700 is provided at the A1 end of the first output member 61 and provides an oil-tight seal between the first output member 61 and the case 2. In a modified example, instead of the output shaft housing chamber S3 communicating with the space S31 where the bearing BR2 and oil seal 700 are located, the axial A1 end of the output shaft housing chamber S3 may enclose the said space S31 (the space where the bearing BR2 and oil seal 700 are located).

[0056] In this embodiment, oil is circulated within the vehicle drive unit 100 by a lubrication method (natural lubrication method) in which oil is stirred up by the rotation of gears, rather than by a so-called forced lubrication method using an oil pump (mechanical or electric oil pump). However, in modified cases, an oil pump may be used in combination for some of the lubrication.

[0057] Specifically, in this embodiment, a lubrication method is employed in which various objects to be lubricated are lubricated by scraping them up with the rotation of the output gear 30 (so-called differential ring) of the differential gear mechanism 5.

[0058] In this way, according to this embodiment, by adopting such a natural lubrication method in the vehicle drive unit 100, it is possible to reduce costs and size by eliminating the oil pump.

[0059] On the other hand, with natural lubrication, properly supplying oil to the aforementioned bearing BR2 and oil seal 700 often necessitates raising the oil level or installing additional components such as catch tanks. Raising the oil level increases the required oil volume, leading to increased costs.

[0060] Therefore, in this embodiment, the surface 231 of the output shaft case portion 23 facing the first output member 61 (hereinafter also referred to as the "inner peripheral wall surface 231") (see Figure 5), and the outer peripheral surface of the first output member 61 are configured such that the axial A1 side extends to a lower position than the axial A2 side.

[0061] Specifically, the inner surface 231 of the peripheral wall includes an inclined surface that forms a height difference between the axial A1 side and the axial A2 side. Such an inclined surface may be realized by increasing the inner diameter of the inner surface 231 of the peripheral wall (inner diameter around the first axis C1) as it moves toward the axial A1 side. However, in other embodiments, a step may be formed instead of or in addition to the inclined surface. In this case as well, the step may be formed such that the inner diameter of the inner surface 231 of the peripheral wall (inner diameter around the first axis C1) increases in stages as it moves toward the axial A1 side.

[0062] Similarly, the outer circumferential surface of the first output member 61 also includes an inclined surface that forms a height difference between the axial A1 side and the axial A2 side. Such an inclined surface may be realized by increasing the outer diameter of the outer circumferential surface of the first output member 61 (outer diameter around the first axis C1) as it moves toward the axial A1 side. In this case, the outer diameter of the outer circumferential surface of the first output member 61 may be a constant value smaller than the inner diameter of the inner circumferential surface 231 of the peripheral wall at each position along the axial direction. However, in other embodiments, steps may be formed instead of or in addition to the inclined surface.

[0063] The inner circumferential surface 231 of the peripheral wall and the outer circumferential surface of the first output member 61 can utilize the action of gravity to allow oil supplied from the axial A2 side by the rotation of the output gear 30 of the differential gear mechanism 5 to flow along the inclined surface towards the axial A1 side at a relatively large flow rate. Specifically, the oil supplied from the axial A2 side by the rotation of the output gear 30 of the differential gear mechanism 5 (see arrow R61 in Figure 5) falls onto the surface of the first output member 61 and then flows along the surface of the first output member 61 towards the axial A1 side (see arrow R62 in Figure 5). At this time, the inclination of the surface of the first output member 61 promotes the flow of oil towards the axial A1 side. In addition, the oil supplied from the axial A2 side by the rotation of the output gear 30 of the differential gear mechanism 5 (see arrow R61 in Figure 5) falls either via the surface of the first output member 61 or directly onto the upward-facing surface portion of the inner circumferential surface 231 of the peripheral wall. Subsequently, the oil flows along the upward-facing surface portion of the inner circumferential wall surface 231 toward the axial direction A1 (see arrow R63 in Figure 5). At this time, the inclination of the inner circumferential wall surface 231 promotes the flow of oil toward the axial direction A1. As a result, oil can be supplied at an appropriate flow rate to the lubrication target (bearing BR2 or oil seal 700) located at or near the A1-side end of the first output member 61.

[0064] In this embodiment, without providing additional parts such as a catch tank, the oil scooped up by the rotation of the output gear 30 of the differential gear mechanism 5 can be appropriately supplied to the lubricated objects (bearing BR2 and oil seal 700). Therefore, while achieving miniaturization and cost reduction through a natural lubrication method, oil can be appropriately supplied to lubricated objects (bearing BR2 and oil seal 700) located relatively far in the axial direction from the output gear 30 of the differential gear mechanism 5.

[0065] Incidentally, in order to supply oil to the lubricated objects (bearing BR2 and oil seal 700) at an appropriate flow rate, it is useful to introduce the oil, which is scooped up by the rotation of the output gear 30 of the differential gear mechanism 5, into the output shaft housing chamber S3 from the axial side A2 at an appropriate flow rate.

[0066] Therefore, in this embodiment, the portion of the transmission mechanism case 22 located at the boundary with the output shaft case 23 in the axial direction (hereinafter also referred to as the "bearing support portion 223") has a cavity portion S223. The bearing support portion 223 is located around the bearing BR1 and is the part that supports the bearing BR1. In this case, the cavity portion S223 is located radially outward of the bearing BR1 and may be formed at a height over which oil scraped up by the rotation of the output gear 30 of the differential gear mechanism 5 is applied. Two or more cavities S223 may be provided around the bearing BR1, for example, directly above (at the 12 o'clock position) and at a position below directly above (for example, at the 11 o'clock position).

[0067] By providing such a cavity S223, the oil sloshed up by the rotation of the output gear 30 of the differential gear mechanism 5 can be introduced into the output shaft housing chamber S3 from the axial A2 side at an appropriate flow rate. Furthermore, the oil sloshed up by the rotation of the output gear 30 of the differential gear mechanism 5 can be directly introduced into the cavity S223. Therefore, it can be introduced into the output shaft housing chamber S3 from the axial A2 side at an appropriate flow rate without the need for additional parts such as a catch tank.

[0068] In this embodiment, as shown in Figures 2 and 5, the oil supplied to the motor housing chamber S1 and the output shaft housing chamber S3 for lubrication is returned to the transmission mechanism housing chamber S2 (particularly the differential gear housing chamber S22) via a return passage 290 formed in the lower part of the case 2.

[0069] The return passage 290 has an A2-side end that opens into the differential gear housing chamber S22 and an A1-side end that communicates with the output shaft housing chamber S3. In this case, the A1-side end of the return passage 290 opens into the space in the output shaft housing chamber S3 that is formed in the axial direction by the case member 200 and the motor cover member 201. The return passage 290 is located below the output shaft housing chamber S3 (and the first output member 61 within it), and the A1-side end of the return passage 290 is located below the output shaft case portion 23. The output shaft case portion 23 may have an opening or notch 99 (see Figure 3) to ensure communication between the output shaft housing chamber S3 and the return passage 290. This allows oil to be efficiently introduced from inside the output shaft housing chamber S3 into the return passage 290.

[0070] Next, referring mainly to Figures 6 and 8, we will primarily describe the structure within the transmission mechanism housing chamber S2 of the oil passage structure.

[0071] In this embodiment, as described above, a natural lubrication method is employed, so it is useful to return the oil used to lubricate various lubricated objects to the lower part of the differential gear housing chamber S22 (the oil reservoir in which the output gear 30 is immersed) relatively quickly. For example, if a return passage such as the return passage 290 described above opens to the reduction mechanism housing chamber S21, which is part of the transmission mechanism housing chamber S2 other than the differential gear housing chamber S22, there is a tendency for insufficient oil to return to the lower part of the differential gear housing chamber S22 via the return passage. In this case, depending on the vehicle's driving conditions, the oil temperature sensor may not be immersed in oil and may measure the internal air temperature instead. To eliminate such inconveniences, it is possible to increase the total amount of oil, but in this case, problems such as increased costs due to the increased amount of oil and increased agitation losses due to the rise in the oil level in a static state (agitation losses by the output gear 30) may arise.

[0072] Therefore, in this embodiment, the return passage 290 opens at the lower part of the differential gear housing chamber S22 (below the second shaft C2) within the transmission mechanism housing chamber S2. In this case, the axial end of the return passage 290 on the A2 side (the opening on the differential gear housing chamber S22 side) preferably overlaps with the output gear 30 when viewed in the axial direction. This makes it possible to return the oil used to lubricate various lubricated objects, including the bearing BR2 and oil seal 700 mentioned above, to the lower part of the differential gear housing chamber S22 (the oil reservoir in which the output gear 30 is immersed) relatively quickly.

[0073] In this embodiment, as described above, a flow path forming member 90 is provided on the radially outer side of the rotating electric machine 1. The radially inner side of the flow path forming member 90 is fitted to the stator core 12, and the radially outer side is sealed on both axial sides against the flow path forming surface 209 of the case 2. That is, the flow path forming member 90 is provided in such a manner that it partitions the movement of oil between the space S11 (see Figure 2) where the coil end 13 on the axial A2 side (in this embodiment, the lead-side coil end 13) is located in the motor housing chamber S1, and the space S12 (see Figure 2) where the coil end 13 on the axial A1 side is located. For this reason, the space S11 (see Figure 2) where the coil end 13 on the axial A2 side (in this embodiment, the lead-side coil end 13) is located in the motor housing chamber S1, and the space S12 (see Figure 2) where the coil end 13 on the axial A1 side is located, are not substantially in communication between their axial directions. In other words, a refrigerant flow path 300 is formed over the entire circumferential area of ​​the rotating electric machine 1, and there is no gap between the rotating electric machine 1 and the flow path forming member 90 in the radial direction. Therefore, no movement of oil through this gap (movement between space S11 and space S12) occurs. Consequently, the oil ejected towards each coil end 13 via the axial oil passage 15a of the rotor shaft 15 and the radial ejection holes 15b of the rotor shaft 15 (oil ejected by centrifugal force during rotor rotation) cannot be returned to the transmission mechanism housing chamber S2 by a single return flow path. Specifically, the oil injected into the coil end 13 in space S12 can be returned to the transmission mechanism housing chamber S2 (especially the differential gear housing chamber S22) by the return flow path 290 described above, due to the communication between space S12 and the output shaft housing chamber S3 (see Figure 2). On the other hand, the oil injected into the coil end 13 in space S11 cannot be returned to the transmission mechanism housing chamber S2 (especially the differential gear housing chamber S22) by the return flow path 290 described above.

[0074] Therefore, in this embodiment, a second return passage, a return passage 292, is provided that connects the space S11 and the transmission mechanism housing chamber S2. Specifically, the end of the return passage 292 on the axial A1 side communicates with the space S11 of the motor housing chamber S1, and the end on the axial A2 side communicates with the lower part of the transmission mechanism housing chamber S2 (the lower part of the catch tank 920, which will be described later). In this embodiment, the end of the return passage 292 on the axial A2 side opens to the lower part of the reduction mechanism housing chamber S21 (below the first axis C1). In this case, the end of the return passage 292 on the axial A2 side (the opening on the reduction mechanism housing chamber S21 side) preferably opens below the second axis C2. This makes it possible to return the oil used to cool the coil end 13 in the space S11 described above to the lower part of the differential gear housing chamber S22 (the oil reservoir in which the output gear 30 is immersed) via the reduction mechanism housing chamber S21. In other words, while a water-cooling structure is realized around the stator core 12 by the flow path forming member 90, the oil supplied to the motor housing chamber S1 can be efficiently returned to the lower part of the differential gear housing chamber S22 (the oil reservoir in which the output gear 30 is immersed).

[0075] In this embodiment, the axial end A2 of the return passage 292 (the opening on the reduction mechanism housing chamber S21 side) is located inside the catch tank 920 within the reduction mechanism housing chamber S21. As shown in Figure 8, the return passage 292 may be in the form of a hole that penetrates axially through the partition wall 26 that axially separates the motor housing chamber S1 and the transmission mechanism housing chamber S2 in the case 2.

[0076] As shown in Figure 6, the catch tank 920 extends radially outward from the axial wall portion 9201 around the reduction mechanism 34 in the reduction mechanism housing chamber S21 and has an inlet 921 at a position capable of capturing oil scraped up by the rotation of the output gear 30. The catch tank 920 also has an outlet 922 at its lower part that opens into the differential gear housing chamber S22. In this case, the axial A2 end of the return passage 292 (the opening on the reduction mechanism housing chamber S21 side) may be provided near the outlet 922. This makes it possible to return the oil used to cool the coil end 13 in the space S11 to the lower part of the differential gear housing chamber S22 (the oil reservoir in which the output gear 30 is immersed) relatively quickly via the lower part of the catch tank 920. The catch tank 920 may also be connected to the axial oil passage 15a of the rotor shaft 15, etc., to supply oil to the axial oil passage 15a of the rotor shaft 15. Furthermore, the lower part of the catch tank 920 refers to the portion below the vertical center of the catch tank 920, for example, the portion below the first shaft C1.

[0077] In the modified configuration, the return channel 292 may be connected to the return channel 290 described above. For example, the return channel 292 may be formed as a channel connecting space S11 and the return channel 290. In this case, the overall length of the return channel can be reduced, and an efficient return channel configuration can be achieved.

[0078] An oil temperature sensor 98 (schematically shown as a circle in Figure 6) is provided at the bottom of the catch tank 920. In this case, the oil temperature sensor 98 is located near the outlet 922 of the catch tank 920. This reduces the possibility that the oil temperature sensor 98 may rise above the oil level depending on the vehicle's driving conditions, thereby improving the reliability of the sensor information from the oil temperature sensor 98.

[0079] In this embodiment, as described above, the oil scraped up by the rotation of the output gear 30 of the differential gear mechanism 5 is introduced from the transmission mechanism housing chamber S2 to the output shaft housing chamber S3 via the cavity S223 located above the second shaft C2. The oil then flows downward due to gravity, lubricating the bearing BR2 and the like, and is returned from the output shaft housing chamber S3 to the differential gear housing chamber S22 via the end of the return passage 290 located below the second shaft C2 (the end on the axial direction A2 side). This makes it possible to scrape the oil again by the rotation of the output gear 30 of the differential gear mechanism 5.

[0080] Furthermore, the oil stirred up by the rotation of the output gear 30 of the differential gear mechanism 5 is introduced into the axial oil passage 15a of the rotor shaft 15 via the catch tank 920. Specifically, the catch tank 920 is provided with a communication port 75 at its top. The communication port 75 is the radially outer opening of the radial communication passage 74, and the radially inner end of the communication passage 74 is connected to the axial oil passage 16a of the input member 16. In this case, the oil stirred up by the rotation of the output gear 30 of the differential gear mechanism 5 enters the communication passage 74 from the communication port 75 of the catch tank 920, and is then supplied to the axial oil passage 15a of the rotor shaft 15 via the axial oil passage 16a. The oil supplied to the axial oil passage 15a is ejected from the ejection hole 15b to the coil end 13 of the rotating electric machine 1, as described above. This allows the coil end 13 to be efficiently cooled by the oil churned up by the rotation of the output gear 30 of the differential gear mechanism 5. The oil sprayed onto the coil end 13 in space S12 of the motor housing chamber S1 is returned from space S12 to the transmission mechanism housing chamber S2 via the end of the return passage 290 located below the second shaft C2 (the end on the axial A2 side). Similarly, the oil sprayed onto the coil end 13 in space S11 of the motor housing chamber S1 is returned from space S11 to the transmission mechanism housing chamber S2 via the end of the return passage 292 located below the second shaft C2 (the end on the axial A2 side). The oil returned to the transmission mechanism housing chamber S2 in this way is returned to the differential gear housing chamber S22 from the outlet 922 in the catch tank 920 located below the second shaft C2. This makes it possible to churn it up again by the rotation of the output gear 30 of the differential gear mechanism 5.

[0081] Although each embodiment has been described in detail above, the invention is not limited to any particular embodiment, and various modifications and changes are possible within the scope described in the claims. Furthermore, it is possible to combine all or more of the components of the embodiments described above.

[0082] For example, in the embodiment described above, both the surface of the output shaft case portion 23 facing the first output member 61 (the inner surface of the peripheral wall 231) and the outer surface of the first output member 61 have inclined surfaces, but the embodiment is not limited to this. For example, only the inner surface of the peripheral wall 231 may have an inclined surface.

[0083] Furthermore, in the above-described embodiment, the output shaft case portion 23 is in the form of a peripheral wall portion that surrounds the first output member 61 in at least a portion of the axial direction of the first output member 61, but it is not limited to this. For example, the output shaft case portion 23 may face only a portion of the area around the first output member 61, including the lower side. [Explanation of symbols]

[0084] 100...Vehicle drive unit, 1...Rotating electric machine, 15...Rotor shaft, 15a...Shaft oil passage, 2...Case, 21...Motor case section (rotating electric machine case section), 231...Inner surface of peripheral wall (surface of peripheral wall section), 26...Partition wall, 200...Case member, 201...Motor cover member (cover member), 290...Return passage (second connecting passage), 292...Return passage (first connecting passage), 34...Reduction mechanism (transmission mechanism), 30...Output gear YA (gear), 5... Differential gear mechanism (transmission mechanism), 61... First output member (shaft member), 300... Refrigerant flow path, 90... Flow path forming member, 98... Oil temperature sensor, 920... Catch tank, BR1... Bearing (first bearing), BR2... Bearing (lubricated object, second bearing), S1... Motor housing chamber (second housing chamber), S22... Differential gear housing chamber (first housing chamber), S3... Output shaft housing chamber (third housing chamber), W... Wheel

Claims

1. Rotating electric machines and, A transmission mechanism that transmits the driving force from the aforementioned rotating electric machine to the wheel via a shaft member, The case and, A flow path forming member housed in or formed as part of the case, which forms a refrigerant flow path around the rotating electric machine, The system comprises a lubrication target which is part of the transmission mechanism or is provided separately from the transmission mechanism and is positioned toward the end of the shaft member closest to the wheel, Inside the aforementioned case, A first containment chamber in which oil that can be scooped up by the rotation of the gears of the transmission mechanism accumulates, A second housing chamber for housing the aforementioned rotating electric machine, A third housing chamber for housing the shaft member, A first connecting passage is provided in the partition wall between the first and second storage chambers in the case in the axial direction, The second connecting passageway, Formed, The aforementioned shaft member is a separate shaft from the rotating electric machine. The flow path forming member separates the movement of oil between the space on one axial end of the rotating electric machine that is connected to the transmission mechanism and the space on the other axial end of the rotating electric machine. The first connecting passage has one end that communicates with the space on the axial side of the second containment chamber, and the other end that communicates with the first containment chamber. A vehicle drive device wherein one end of the second connecting passage communicates with the space on the other axial end side of the second housing chamber and communicates with the third housing chamber so that oil used to lubricate the object to be lubricated is introduced into the second connecting passage, and the other end communicates with the first housing chamber and is provided below the shaft member.

2. The third storage chamber has one end that opens into the first storage chamber so that oil, which is stirred up by the rotation of the gear, is introduced, and the other end that communicates with the second storage chamber, The second connecting passage has one end that communicates with the second containment chamber so that the oil used to lubricate the object to be lubricated is introduced, and the other end that opens to the first containment chamber. The vehicle drive device according to claim 1, wherein the other end of the first connecting passage opens into the first housing chamber, or communicates with the first housing chamber via the second connecting passage.

3. The axis of the shaft member is parallel to the axis of the rotating electric machine and offset to one side in the front-rear direction. Within the aforementioned case, further, A catch tank extending around the axis of the rotating electric machine, communicating with the first containment chamber, and capable of capturing oil stirred up by the rotation of the gear, The lower part of the catch tank has an outlet that opens into the first containment chamber, A vehicle drive device according to claim 2, wherein the following is formed.

4. The other end of the second connecting passage overlaps with the gear when viewed in the axial direction. The other end of the first connecting passage opens to the lower part of the catch tank, as described in claim 3.

5. The vehicle drive system according to claim 3 or 4, further comprising an oil temperature sensor at the lower part of the catch tank.

6. Furthermore, within the aforementioned case, an axial oil passage is formed in the rotor shaft of the rotating electric machine. The axial oil passage communicates with the space at one axial end and the space at the other axial end of the second containment chamber. The vehicle drive device according to claim 3, wherein the catch tank is in communication with the shaft oil passage so that oil stirred up by the rotation of the gear is supplied to the shaft oil passage.

7. The case includes a case member positioned radially outward of the rotating electric machine and radially outward of the shaft member, and a cover member joined to the case member and covering the other axial end of the rotating electric machine in the axial direction. The vehicle drive device according to claim 1, wherein one end of the second connecting passage opens in the axial direction into a space formed by the case member and the cover member.

8. The vehicle drive device according to claim 1, wherein the flow path forming member blocks the direct flow of oil between the space on one axial end side of the rotating electric machine and the space on the other axial end side of the rotating electric machine in the second housing chamber.

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