Drive device

Abstract

[Problem] To enable adjustment of lubricating oil supply timing. [Solution] This drive device comprises a motor and a case that houses a power transmission mechanism. The case has a housing unit for the power transmission mechanism. In the housing unit, when viewed from the axial direction of an input shaft, an intermediate shaft is positioned between the input shaft and an output shaft, and the axis of the intermediate shaft is positioned above the axis of the input shaft and the axis of the output shaft. The housing unit is provided with a rib that extends above an input shaft gear from a side opposite to an output shaft gear when viewed from the input shaft gear, and that has a distal end positioned above a proximal end, and the upper side of the rib serves as a catch tank capable of capturing lubricating oil. The rib has an intermediate rib extending upward from between the distal end and the proximal end, and the distal end of the intermediate rib is positioned above the distal end of the rib.

Description

Drive device

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

[0002] Patent Document 1 discloses a vehicle drive device that is configured to allow adjustment of the time it takes for lubricating oil captured in an oil catch tank to be supplied to a lubricating site.

[0003] Japanese Unexamined Patent Application Publication No. 2010-174961

[0004] The oil catch tank of Patent Document 1 includes a capacity varying device that increases or decreases the capacity of a tank portion for storing lubricating oil. The capacity varying device increases or decreases the capacity of the tank portion to adjust the oil level position of the lubricating oil captured in the tank portion between a first oil level position that is substantially at the same height as the lower side of a lubricating oil discharge port and a second oil level position that is higher than the first oil level position.

[0005] For example, when a vehicle equipped with the vehicle drive device starts moving from a stopped state, setting the capacity of the tank portion to the minimum capacity state shortens the time it takes for the oil level of the captured lubricating oil to exceed the height of the lubricating oil discharge port. As a result, the time it takes for the lubricating oil that has flowed into the lubricating oil discharge port to be supplied to the lubricating oil supply destination can be shortened, so that the supply destination can be properly lubricated even in a situation where lubricating oil tends to be insufficient immediately after starting.

[0006] In the case of Patent Document 1, the supply timing of lubricating oil is adjusted by increasing or decreasing the capacity of the tank portion using the load of the captured lubricating oil and a compression coil. However, there is a demand for enabling adjustment of the supply timing of lubricating oil captured in the oil catch tank with a simpler configuration.

[0007] One aspect of the present invention is a drive device comprising: a motor; a power transmission mechanism for transmitting power from the motor to a drive wheel; and a case for housing the motor and the power transmission mechanism, wherein the power transmission mechanism comprises: an input shaft to which power from the motor is input; an intermediate shaft to which power input to the input shaft is transmitted; an output shaft to which power transmitted to the intermediate shaft is transmitted; an input shaft gear provided on the input shaft; an output shaft gear provided on the output shaft; a first intermediate shaft gear provided on the intermediate shaft and rotatably meshing with the input shaft gear; and a second intermediate shaft gear provided on the intermediate shaft and rotatably meshing with the output shaft gear, wherein the case has a housing portion for the power transmission mechanism, and in the housing portion, the intermediate shaft is located between the input shaft and the output shaft when viewed from the axial direction of the input shaft, and the axis of the intermediate shaft is located above the axis of the input shaft and the axis of the output shaft. A rib is provided that extends from the opposite side of the input shaft gear to the output shaft gear as viewed from the input shaft gear, up to the top of the input shaft gear, with its tip positioned above its base end. The part above the rib serves as an oil catch tank capable of capturing lubricating oil. The rib is provided with an intermediate rib that extends upward from between its tip and base end, with the tip of the intermediate rib positioned above the tip of the rib.

[0008] According to one aspect of the present invention, the timing of supplying lubricating oil captured in the oil catch tank can be adjusted with a simple configuration such as ribs and intermediate ribs formed on the case.

[0009] Figure 1 is a schematic diagram of the drive unit. Figure 2 is a schematic diagram showing the second cover as viewed from the motor case side. Figure 3 is a schematic enlarged view of the area around the catch tank of the second cover. Figure 4 is a schematic enlarged view of the area around the catch tank of the motor case. Figure 5 is a diagram illustrating the catch tank. Figure 6 is a diagram illustrating the catch tank. Figure 7 is a diagram illustrating the catch tank. Figure 8 is a diagram illustrating a modified catch tank. Figure 9 is a diagram illustrating a modified catch tank. Figure 10 is a diagram illustrating the operation of a modified catch tank.

[0010] First, the definitions of terms used in this specification will be explained. A drive unit is a device having at least a motor, an inverter, and a power transmission mechanism. A "motor" is a rotating electric machine having electric motor function and / or generator function. An "inverter" is a device that supplies driving current to the motor M. A "power transmission mechanism" is, for example, at least one of a gear mechanism, a differential gear mechanism, and a reduction mechanism. A "housing" is a device that houses the motor, gears, and inverter. The housing consists of one or more cases.

[0011] In this specification, "rib" refers to a protruding portion formed to perform functions such as improving the rigidity of a member, suppressing deformation, positioning, guiding, or distributing load. The cross-sectional shape, width, height, continuity, and formation location of a rib (protruding portion) are not limited to a specific shape. "Intermediate rib" refers to a rib placed between multiple ribs or within a predetermined area. An intermediate rib does not necessarily have to be placed in the center of a specific part. An intermediate rib only needs to play a functionally intermediate role and may be placed off-center.

[0012] "Overlapping in a specified direction" means that multiple elements are aligned in a specified direction, and is synonymous with the statement "overlapping in a specified direction." The "specified direction" can be, for example, the axial direction, radial direction, vertical direction (direction of gravity), or vehicle travel direction (vehicle forward direction, vehicle reverse direction). If multiple elements (parts, sections, etc.) are shown aligned in a specified direction on the drawing, it can be assumed that there is a statement in the specification explaining that they overlap in a specified direction.

[0013] "Not overlapping in a given direction" and "offset in a given direction" mean that multiple elements are not aligned in a given direction, and are equivalent to stating "not overlapping in a given direction" and "offset in a given direction." A "given direction" can be, for example, the axial direction, radial direction, vertical direction (direction of gravity), or vehicle travel direction (vehicle forward direction, vehicle reverse direction). If a drawing shows that multiple elements (parts, sections, etc.) are not aligned in a given direction, it can be assumed that the description in the specification includes a statement explaining that they do not overlap in a given direction.

[0014] The statement "In a predetermined viewing direction, the first element (part, component, etc.) is located between the second element (part, component, etc.) and the third element (part, component, etc.)" means that, when observed from a predetermined direction, the first element can be observed to be located between the second and third elements. The "predetermined direction" includes the axial direction, radial direction, vertical direction (direction of gravity), and vehicle travel direction (vehicle forward direction, vehicle reverse direction). For example, if the second, first, and third elements are arranged in this order along the axial direction, then in a radial viewing direction, the first element can be said to be located between the second and third elements. If the drawing shows that the first element is located between the second and third elements in a predetermined viewing direction, then it can be assumed that there is a sentence in the specification explaining that the first element is located between the second and third elements in a predetermined viewing direction.

[0015] "Axial direction" refers to the axial direction (direction along the rotational centerline) of the rotation axis of the components that make up the drive system. "Radial direction" refers to the direction perpendicular to the rotation axis of the components that make up the drive system. Examples of components include motors, gear mechanisms, differential gear mechanisms, etc.

[0016] Hereinafter, embodiments of the present invention will be described using the case of a drive unit 1 mounted on a vehicle as an example. Figure 1 is a schematic diagram of the drive unit 1.

[0017] In the following explanation, the vertical direction (direction of gravity) may be denoted by the symbol "Z", the vehicle's width direction by the symbol "X", and the vehicle's longitudinal direction by the symbol "Y", based on the installation state of the drive unit 1 on the vehicle. Here, the X direction is the direction along the rotation axis of the motor M of the drive unit 1, and is the vehicle's width direction. The Y direction is the horizontal direction perpendicular to the vertical line passing through the rotation axis of the motor M of the drive unit 1, and is the vehicle's longitudinal direction. Furthermore, "up and down direction" in the drawings refers to the vertical direction based on the state in which the drive unit 1 is mounted on the vehicle. Therefore, when "upper side" is written, it means the "upper side" in the vertical direction, and when "lower side" is written, it means the "lower side" in the vertical direction.

[0018] As shown in Figure 1, in the housing HS (case) of the drive unit 1, a first cover 3 is fixed to one side (lower side in the figure) of the motor case 2 in the X direction. The first cover 3 seals the opening of the motor case 2. As a result, a motor chamber S1 for housing the motor M is formed between the motor case 2 and the first cover 3. In the housing HS, a second cover 4 is fixed to the other side (upper side in the figure) of the motor case 2 in the X direction. As a result, a gear chamber S2 (housing section for the power transmission mechanism) for housing the power transmission mechanism 5 and the differential mechanism 6 is formed between the motor case 2 and the second cover 4.

[0019] The housing HS houses a motor M and a power transmission mechanism 5. The power transmission mechanism 5 has an input shaft 51, an intermediate shaft 52, and a differential mechanism 6. The input shaft 51 has a shaft portion 510 that rotates integrally with the output shaft of the motor M, and a transmission gear 511 (input shaft gear) provided on the outer circumference of the shaft portion 510. The transmission gear 511 is not rotatable relative to the shaft portion 510. The shaft portion 510 is arranged concentrically with the output shaft (rotation axis: axis X1) of the motor M. The shaft portion 510 is connected to the output shaft (not shown) of the motor M in a way that prevents relative rotation. The output rotation (power) of the motor M is input to the input shaft 51. The shaft portion 510 and the transmission gear 511 rotate integrally around axis X1 by the power input from the motor M.

[0020] The intermediate shaft 52 has a shaft portion 520 oriented along the axis X2. When viewed from the Z direction, the axis X2 is parallel to the axis X1. On the outer circumference of the shaft portion 520, a first gear 521 (first intermediate shaft gear) and a second gear 522 (second intermediate shaft gear) are provided at intervals in the longitudinal direction (axis X2 direction). The first gear 521 and the second gear 522 are not rotatable relative to the shaft portion 520.

[0021] The first gear 521 is rotatably meshed with the transmission gear 511 of the input shaft 51. The second gear 522 is rotatably meshed with the final gear F on the differential mechanism 6 side. The output rotation of the motor M is transmitted to the intermediate shaft 52 via the first gear 521, which meshes with the transmission gear 511. The rotation transmitted to the intermediate shaft 52 is then transmitted to the differential mechanism 6 side via the final gear F, which meshes with the second gear 522.

[0022] The differential mechanism 6 has a differential case DEF that is rotatable around axis X3. Inside the differential case DEF are a pair of pinion gears 61, 61 and a pair of side gears 62, 62. The side gears 62, 62 are connected to drive shafts DS, DS (output shafts) which are oriented along axis X3. The side gears 62, 62 mesh with the pinion gears 61, 61 so as to transmit rotational power.

[0023] A final gear F is fixed to the outer circumference of the differential case DEF. The differential case DEF rotates around axis X3 due to the rotation transmitted from the intermediate shaft 52 to the final gear F. The rotation of the differential case DEF around axis X3 is transmitted to the left and right drive shafts DS, DS (output shafts) via pinion gears 61, 61 and side gears 62, 62. In the drive unit 1, the output rotation (power) of the motor M, which is the drive source, is input to the power transmission mechanism 5. The input power is reduced in speed and then transmitted via the differential mechanism 6 to the drive shafts DS and the drive wheels WH, WH connected to DS.

[0024] If we consider the drive shafts DS, DS as vehicle body components that mount the drive unit 1, then the side gears 62, 62 of the differential mechanism 6 can be said to correspond to the output shaft in the invention. The axis X3 is the common axis of rotation for the differential mechanism 6 (differential case DEF, side gears 62, 62, final gear F) and the drive shafts DS, DS.

[0025] Figure 2 is a schematic diagram showing the second cover 4 as viewed from the motor case 2 side. In Figure 2, in order to make the positions of the peripheral wall portion 42 surrounding the outer circumference of the side wall portion 41 and the rib 46 (described later) easier to understand, intersecting hatching is added to the areas of the peripheral wall portion 42 and the rib 46.

[0026] The second cover 4 has a side wall portion 41 and a peripheral wall portion 42. When viewed from the direction of the rotation axis (axis X1) of the motor M, the side wall portion 41 is sized to cover the sides of the power transmission mechanism 5 (input shaft 51, intermediate shaft 52, and differential mechanism 6). The side wall portion 41 and the power transmission mechanism 5 are positioned in an overlapping position in the X direction (see Figure 1). As shown in Figure 2, the peripheral wall portion 42 surrounds the outer circumference of the side wall portion 41 all the way around. The peripheral wall portion 42 protrudes from the side wall portion 41 towards the front side of the paper (motor case 2). The end face of the peripheral wall portion 42 on the front side of the paper is the joint surface with the motor case 2.

[0027] Inside the peripheral wall portion 42 are the input shaft 51, the intermediate shaft 52, and the differential mechanism 6, which is rotatably connected to the drive shaft DS (output shaft). Inside the peripheral wall portion 42, the axis (axis X1) of the input shaft 51 and the axis (axis X3) of the differential mechanism 6 are spaced apart in the Y direction. In this state, the axis X3, which is the rotation axis of the final gear F (differential mechanism 6), is located below the axis X1, which is the rotation axis of the input shaft 51, in the Z direction.

[0028] Between axis X3 and axis X1 in the Y direction, the axis of the intermediate shaft 52 (axis X2) is located above axis X1. On the intermediate shaft 52, the first gear 521 is located on the far side of the paper, and the second gear 522 is located on the near side of the paper. The second gear 522 has a smaller diameter than the first gear 521. The first gear 521 is rotatably meshed with the transmission gear 511 on the input shaft 51 side at the far side of the paper. The second gear 522 is rotatably meshed with the final gear F at the near side of the paper.

[0029] The meshing position (meshing portion E1) between the first gear 521 and the transmission gear 511, and the meshing position (meshing portion E2) between the second gear 522 and the final gear F are offset in the X direction. The meshing portion E1 between the first gear 521 and the transmission gear 511 is located further back in the plane of the paper than the meshing portion E2 between the second gear 522 and the final gear F.

[0030] In the second cover 4, a space that functions as a catch tank 7 (oil catch tank) is provided above the horizontal line HL1 in the Z direction. The space that functions as a catch tank 7 is located on the opposite side (right side in the figure) from the final gear F when viewed from the vertical line VL1. Here, the horizontal line HL1 is a horizontal line passing through the axis (axis X1) of the input shaft 51. The vertical line VL1 is a vertical line passing through the axis (axis X1) of the input shaft 51.

[0031] The space that functions as the catch tank 7 is formed between the second cover 4 and the motor case 2 when the second cover 4 is assembled to the motor case 2. The second cover 4 is provided with ribs 46 that form part of the bottom wall of the catch tank 7. The motor case 2 is provided with ribs 26 that form part of the bottom wall of the catch tank 7 (see Figure 4). In this embodiment, when the second cover 4 is assembled to the motor case 2, the ribs 46 on the second cover 4 side and the ribs 26 on the motor case 2 side come into contact with each other in the direction of the rotation axis (axis X1) of the motor M, thereby forming the bottom wall of the catch tank 7.

[0032] Figure 3 is a schematic, enlarged view of the area around the catch tank 7 of the second cover 4. Figure 4 is a schematic, enlarged view of the area around the catch tank 7 of the motor case 2. Figures 5 to 7 illustrate the catch tank 7. Figure 5 schematically shows a cross-section of the area in the housing HS where the catch tank 7 is provided, cut along the line A-A in Figure 3. Figure 6 schematically shows an enlarged view of the area around the recess 48 in the catch tank 7. Figure 7 schematically shows the catch tank 7 as viewed from the direction of the arrow A-A in Figure 6.

[0033] First, let's describe the rib 46 on the second cover 4 side. As shown in Figure 2, on the second cover 4, the rib 46 protrudes from the side wall portion 41 toward the front of the paper (towards the motor case 2). As shown in Figure 5, the rib 46 is provided spanning both the side wall portion 41 and the peripheral wall portion 42. As shown in Figure 2, when viewed from the X direction, the rib 46 has a first region 461 and a second region 462.

[0034] Viewed from the X direction, the first region 461 is a linear region located between horizontal line HL1 and horizontal line HL2, and oriented along horizontal line HL1. Here, horizontal line HL2 is a horizontal line passing through the axis (axis X2) of the intermediate shaft 52. The base end 46b of the rib 46 (first region 461) is located between horizontal line HL1 and horizontal line HLa in the Z direction. Horizontal line HLa is a horizontal line passing through the upper side of the transmission gear 511, and is located between horizontal line HL1 and horizontal line HL2.

[0035] Viewed from the X direction, the second region 462 is an arc-shaped region that surrounds the outer circumference of the transmission gear 511 with a gap between them. Viewed from the X direction, the tip 46a of the second region 462 is located between the horizontal line HL2 and the horizontal line HLa, and is positioned with a gap between it and the outer circumference of the first gear 521. In this state, the tip 46a of the second region 462 is located between the vertical line VL1 and the vertical line VL1a. The vertical line VL1a is a vertical line that passes through the outer circumference of the transmission gear 511 (the outer circumference on the catch tank 7 side). The vertical lines VL1a and VL1 are parallel to each other. Viewed from the vertical line VL1, the vertical line VL1a is located on the opposite side from the final gear F.

[0036] As shown in Figure 5, when the tip 46a of the rib 46 (second region 462) is viewed from the Z direction, the tip 46a is positioned to overlap with the transmission gear 511. In this state, the tip 46a of the rib 46 does not overlap with the first gear 521 and the second gear 522 when viewed from the Z direction. Furthermore, the rib 46 is formed to have a range that crosses the transmission gear 511 in the direction of the axis X1 (left-right direction in the figure).

[0037] As shown in Figure 3, when viewed from the X direction, the tip 46a of the second region 462 of the rib 46 is located on the side of the first gear 521 (above) the normal L2 that passes through the meshing portion E1 between the transmission gear 511 and the first gear 521. The normal L2 is a straight line perpendicular to the straight line L1 that connects the axis X1 and axis X2. In this embodiment, the rib 46 extends from the opposite side of the differential mechanism 6 (right side in the figure) when viewed from the transmission gear 511 to above the transmission gear 511. In the second cover 4, the rib 46 extends from the inner circumference of the peripheral wall portion 42 toward the transmission gear 511, and its tip 46a is located above the base end 46b. The area above this rib 46 is the region of the catch tank 7 capable of capturing oil OL (lubricating oil).

[0038] In rib 46, an intermediate rib 47 is provided between the tip 46a and the base 46b. The intermediate rib 47 extends upward from the second region 462 of rib 46. As shown in Figure 2, the intermediate rib 47 is located between the bent portion 46c of rib 46 and the tip 46a, specifically between the bent portion 46c and the vertical line VL1a. Here, the bent portion 46c refers to the bent part at the boundary between the first region 461 and the second region 462.

[0039] As shown in Figure 3, the tip 47a of the intermediate rib 47 extends linearly upward. The region on the tip 47a side of the intermediate rib 47 is approximately parallel to the vertical lines VL1 and VL1a (see Figure 2). The tip 47a of the intermediate rib 47 is located above the tip 46a of the rib 46, specifically the uppermost upper edge 46a1 at the tip 46a of the rib 46, by a height Δh.

[0040] Therefore, in the catch tank 7 region, the area from the intermediate rib 47 to the tip 46a of the rib 46 is a sub-tank section 7B capable of capturing oil OL. Furthermore, the area enclosed by the intermediate rib 47, the first region 461, and the peripheral wall 42 is the main tank section 7A. The sub-tank section 7B has a smaller volume than the main tank section 7A. The sub-tank section 7B is located on the side (left side in the figure) into which the oil OL scraped up by the final gear F flows, compared to the main tank section 7A. The sub-tank section 7B is located above the main tank section 7A. Viewed from the main tank section 7A, the sub-tank section 7B is located diagonally above the intermediate shaft 52 (diagonally above and to the left in the figure). Viewed from the Y direction, the sub-tank section 7B overlaps with the first gear 521. Viewed from the Y direction, the main tank section 7A overlaps with the first gear 521 and the transmission gear 511. Viewed from the Z direction, the sub-tank section 7B overlaps with the transmission gear 511 in the area on the tip side 46a. Viewed from the Z direction, the main tank section 7A does not overlap with the first gear 521 and the transmission gear 511.

[0041] One end 49a of an oil passage 49 opens at a lower portion of the main tank portion 7A. As shown in FIG. 2, the oil passage 49 extends in the Y direction inside the second cover 4. The other end 49b of the oil passage 49 opens at an inner circumference of a bearing support portion 411 provided on the side wall portion 41. The support portion 411 is formed in a cylindrical shape that surrounds the axis X1 at a predetermined interval. A shaft portion 510 of the input shaft 51 is rotatably supported on the inner circumference of the support portion 411 via the bearing B. The oil trapped in the main tank portion 7A is supplied to the support portion 411 through the oil passage 49, and lubricates the bearing B supported on the inner circumference of the support portion 411.

[0042] Next, the rib 26 on the motor case 2 side will be described. As shown in FIG. 4, the motor case 2 includes a side wall portion 21 and a peripheral wall portion 22. As shown in FIG. 5, the side wall portion 21 is a partition wall that partitions the motor chamber S1 and the gear chamber S2. The side wall portion 21 also has a size that covers the side surface of the power transmission mechanism 5.

[0043] As shown in FIG. 4, in the motor case 2, the rib 26 protrudes from the side wall portion 21 toward the front side of the drawing (the second cover 4 side). As shown in FIG. 5, the rib 26 is provided across the side wall portion 21 and the peripheral wall portion 22. As shown in FIG. 4, when viewed from the X direction, the rib 26 includes a first region 261 and a second region 262.

[0044] When viewed from the X direction, the first region 261 is a linear region provided between the horizontal line HL1 and the horizontal line HL2 in a direction along the horizontal line HL1. A base end 26b of the rib 26 (the first region 261) is located between the horizontal line HL1 and the horizontal line HLa in the Z direction. Here, the horizontal lines HL1, HLa, and HL2 in FIG. 4 are at the same height position (position in the Z direction) as the horizontal lines HL1, HLa, and HL2 in FIG. 2. The vertical line VL1 in FIG. 4 is at the same position (position in the Y direction) as the vertical line VL1 in FIG. 3.

[0045] As viewed from the X direction, the second region 262 is an arc-shaped region surrounding the outer periphery of the support portion 211 with a gap therebetween. A guide wall portion 263 having a circular cross section is provided at the distal end 26a of the second region 262. In the rib 26, an intermediate rib 27 is provided between the distal end 26a and the proximal end 26b. The intermediate rib 27 extends upward from the second region 262 of the rib 26. As shown in Fig. 4, the intermediate rib 27 is located between a bent portion 26c of the rib 26 and the guide wall portion 263 on the distal end 26a side.

[0046] The distal end 27a side of the intermediate rib 27 extends linearly upward. A region on the distal end 27a side of the intermediate rib 27 is substantially parallel to the vertical line VL1. The distal end 27a of the intermediate rib 27 is located lower than the uppermost upper edge 263a of the guide wall portion 263 by a height Δh'.

[0047] Therefore, in the region of the catch tank 7, the range from the intermediate rib 27 to the guide wall portion 263 of the rib 26 serves as a sub-tank portion 7B capable of catching oil OL. Further, a region surrounded by the intermediate rib 27, the first region 261 and the peripheral wall portion 22 serves as a main tank portion 7A. The shape of the rib 26 (from the proximal end 26b to the distal end 26a) as viewed from the axis X1 direction and the shape of the intermediate rib 27 are substantially the same as the shape of the rib 46 (from the proximal end 46b to the distal end 46a) on the second cover 4 side as viewed from the axis X1 direction and the intermediate rib 47. With the joint surface PL between the second cover 4 and the motor case 2 (see Fig. 1) as a boundary, the shapes of the rib 26 and the intermediate rib 27 are substantially symmetrical to the shapes of the rib 46 and the intermediate rib 47.

[0048] Therefore, when the second cover 4 and the motor case 2 are joined together, the rib 46 and the intermediate rib 47 on the second cover 4 side contact the rib 26 and the intermediate rib 27 on the motor case 2 side over substantially the entire surface. Thus, a region serving as the catch tank 7 is formed (see Fig. 5).

[0049] One end 29a of the oil passage 29 is open at the bottom of the main tank section 7A. The oil passage 29 extends in the Y direction inside the motor case 2. The other end 29b of the oil passage 29 is open to the inner circumference of the bearing support section 211 provided on the side wall section 21. The support section 211 is cylindrical in shape and surrounds the axis X1 at predetermined intervals. The shaft portion 510 of the input shaft 51 is rotatably supported on the inner circumference of the support section 211 via the bearing B. The oil captured in the main tank section 7A is supplied to the support section 211 through the oil passage 29 and lubricates the bearing B supported on the inner circumference of the support section 211.

[0050] As shown in Figure 6, when viewed from the Z direction, the rib 46 of the second cover 4 has a recess 48 on the motor case 2 side (right side in the figure) on the tip 46a side and a recess 48 on the intermediate rib 47 side (upper side in the figure). When viewed from the Z direction, the recess 48 has a linear region 481 that is substantially parallel to the tip 46a of the rib 46 and a connecting region 482 that connects the linear region 481 and the tip 46a of the rib 46. When viewed from the Z direction, the linear region 481 is positioned offset from the tip 46a of the rib 46 toward the intermediate rib 47. Here, the region along the tip 46a of the rib 46 corresponds to the "first side edge" in the invention, and the region along the linear region 481 of the recess 48 corresponds to the "second side edge" in the invention.

[0051] As shown in Figure 3, the straight region 481, when viewed from the X direction, is located between the tip 46a of the rib 46 and the intermediate rib 47. Furthermore, the upper edge 481a of the straight region 481 is located below the upper edge 46a1 of the tip 46a of the rib 46. Therefore, when the amount of oil OL flowing into the sub-tank section 7B is small, the oil OL overflows from the section with the recess 48 (straight region 481) before the section without the recess 48, and falls into the gear chamber S2.

[0052] As shown in Figure 2, lubricating oil OL is stored in the lower part of the gear chamber S2 to lubricate the components of the power transmission mechanism 5. When the vehicle equipped with the drive unit 1 is moving forward, the final gear F rotates clockwise in the figure (arrow Rt direction), scraping up the oil OL stored in the lower part of the gear chamber S2. The scraped-up oil OL moves upward towards the intermediate shaft 52 side along the inner circumference of the peripheral wall portion 42. Then, it passes between the intermediate shaft 52 and the peripheral wall portion 42 and reaches the input shaft 51 side.

[0053] Here, on the opposite side of the intermediate shaft 52 from the final gear F (right side in the figure), and above the input shaft 51, a catch tank 7 capable of capturing oil OL is provided between the ribs 46, 26 and the peripheral wall portions 42, 22 (see Figure 5). As shown in Figure 3, the catch tank 7 opens towards the intermediate shaft 52. Therefore, oil OL that has moved from the final gear F side to the input shaft 51 side along the inner circumference of the peripheral wall portion 42 flows into the catch tank 7 and is captured.

[0054] Here, the sub-tank section 7B is located above the main tank section 7A, closer to the intermediate shaft 52. In other words, in the catch tank 7, the sub-tank section 7B is located on the oil OL inflow side of the main tank section 7A. For example, when a vehicle equipped with the drive unit 1 is traveling at a low speed, and the amount of oil OL scooped up by the final gear F is small, the oil OL that flows into the catch tank 7 will be captured by the sub-tank section 7B before the main tank section 7A.

[0055] Furthermore, the volume of the sub-tank section 7B is significantly smaller than the volume of the main tank section 7A, so that the oil OL stored in the sub-tank section 7B overflows before the oil OL stored in the main tank section 7A. As shown in Figure 3, in the sub-tank section 7B, the upper edge 481a of the straight region 481 is located below the upper edge 46a1 of the tip 46a of the rib 46. Therefore, when the amount of oil OL flowing into the sub-tank section 7B is small, the oil OL will overflow from the portion with the recess 48 (the portion of the straight region 481) before the portion without the recess 48.

[0056] In the second cover 4, which is manufactured by casting, the rib 46 has a casting angle. Therefore, as shown in Figure 7, the rib 46 (bottom surface) is inclined with respect to the horizontal line HLx. Specifically, the end 46e on the side wall portion 41 side (left side in the figure) of the rib 46 in the X direction (left-right direction in the figure) is located lower in the Z direction than the end 46d on the opposite side (right side in the figure).

[0057] Therefore, much of the oil OL that overflows from the straight region 481 (upper edge 481a) of the recess 48 travels along the lower surface of the rib 46 to the end 46e side (left side in the figure) where the recess 48 is not provided, and then falls downward from the end 46e side. As shown in Figure 3, the region of the rib 46 where the recess 48 is not provided (the region on the tip 46a side) has a larger overlap amount with the transmission gear 511 (overlap amount in the left-right direction in the figure) by the amount that the recess 48 is not provided. Furthermore, the tip 46a of the rib 46 is located closer to the meshing portion E1 between the transmission gear 511 and the first gear 521 than the straight region 481.

[0058] Therefore, the oil OL that falls from the area of ​​the rib 46 where the recess 48 is not provided (the area on the tip 46a side) can more effectively lubricate the meshing portion E1 between the transmission gear 511 and the first gear 521. In particular, when the vehicle equipped with the drive unit 1 is traveling at a low speed and the amount of oil OL flowing into the sub-tank section 7B is small, a large portion of the incoming oil OL falls from the area of ​​the rib 46 where the recess 48 is not provided (the first side edge R1 in Figure 6), allowing the meshing portion E1 to be lubricated preferentially.

[0059] Furthermore, when a vehicle equipped with the drive unit 1 is traveling at high speed and a large amount of oil OL is scooped up by the final gear F, a large amount of oil is continuously supplied to the sub-tank section 7B. As a result, oil OL overflows vigorously from the area of ​​the rib 46 where the recess 48 is not provided (first side edge R1 in Figure 6) and from the area where the recess 48 is provided (second side edge R2 in Figure 6), thereby adequately lubricating the meshing portion E1 between the transmission gear 511 and the first gear 521.

[0060] Furthermore, on the motor case 2 side, the upper edge 263a of the guide wall 263 of the rib 26 is positioned above the tip 27a of the intermediate rib 27 by a height Δh'. Therefore, when the amount of oil OL scooped up by the final gear F is small, the amount of captured oil OL that moves along the guide wall 263 towards the rib 46 (recess 48) is greater than the amount that leaks from the rib 26 (third side edge R3 in Figure 6). Thus, more oil OL can be allowed to overflow from the area where the recess 48 is provided (second side edge R2). As a result, when the vehicle equipped with the drive unit 1 is traveling at a low speed and the amount of oil OL flowing into the sub-tank 7B is small, a large portion of the incoming oil OL can be guided to the area where the recess 48 is provided (second side edge R2) on the rib 46, causing it to overflow from the area where the recess 48 is provided. Oil OL that overflows from the area where the recess 48 is provided moves along the lower surface of the rib 46 towards the side wall portion 41, and finally falls into the gear chamber S2 from the area of ​​the first side edge portion R1. As a result, even if the amount of oil OL flowing into the sub-tank portion 7B is small, the meshing portion E1 between the transmission gear 511 and the first gear 521 can be lubricated.

[0061] Here, after being scooped up by the final gear F, some of the oil OL moving downward within the gear chamber S2 moves along the side wall portion 41 (see Figure 2). Of the oil OL moving along this side wall portion 41, the oil OL that reaches the region where the rib 46 is provided (see arrow a in Figure 2) flows into the region of the rib 46 extending from the inner circumference of the side wall portion 41 (see arrow a in Figure 6). The portion of the first side edge portion R1 of the rib 46 is located above the portion of the second side edge portion R2 in the Z direction. Therefore, the oil OL that flows into the region of the rib 46 moves toward the intermediate rib 47, then moves toward the second side edge portion R2 where the recess 48 is provided, and overflows from the portion of the recess 48 (Figure 6). As a result, even when the amount of oil OL scooped up by the final gear F is small, the rib 46, which spans the side wall portion 41 and the peripheral wall portion 42, captures the oil OL flowing along the side wall portion 41 and guides it into the recess 48, so that it can be used for lubrication of the meshing portion E1 between the transmission gear 511 and the first gear 521.

[0062] In the above-described embodiment, an example was given in which the ribs 26 and 46 are composed of a linear first region 261 and 461 and an arc-shaped second region 262 and 462. The shape of the ribs 26 and 46 is not limited to the example given. For example, ribs that extend linearly from the base ends 26b and 46b to the tips 26a and 46a may be used. In this case as well, a sub-tank portion will be formed on the tip 26a and 46a side of the rib, so that the oil OL that overflows from the sub-tank portion can be appropriately guided to the meshing portion E1 between the transmission gear 511 and the first gear 521.

[0063] As described above, the drive device 1 according to the embodiment has the following configuration: (1) The drive device 1 comprises a motor M which is a drive source, a power transmission mechanism 5 which transmits the power (rotational driving force) of the motor M to the drive wheels WH, WH, and a housing HS (case) which houses the motor M and the power transmission mechanism 5. The power transmission mechanism 5 includes an input shaft 51 to which power is input from a motor M; an intermediate shaft 52 to which the power input to the input shaft 51 is transmitted; drive shafts DS, DS (output shafts) to which the power transmitted to the intermediate shaft 52 is transmitted; a transmission gear 511 (input shaft gear) provided on the input shaft 51; a final gear F (output shaft gear) involved in the transmission of power to the drive shafts DS, DS (output shafts); a first gear 521 (first intermediate shaft gear) provided on the intermediate shaft 52 and rotatably meshing with the transmission gear 511; and a second gear 522 (second intermediate shaft gear) provided on the intermediate shaft 52 and rotatably meshing with the final gear F. The housing HS (case) has a gear chamber S2 which is the housing portion of the power transmission mechanism 5. In the gear chamber S2, the intermediate shaft 52 is located between the axis of the input shaft 51 (axis X1) and the axis of the drive shaft DS, DS (output shaft) (axis X3) in the Y direction, as viewed from the axial direction of the input shaft 51 (axis X1 direction). The axis of the intermediate shaft 52 (axis X2) is located above the axis of the input shaft 51 (axis X1) and the axis of the drive shaft DS, DS (output shaft) (axis X3). As viewed from the axial direction of the input shaft 51, axis X1 direction, the gear chamber S2 is provided with a rib 46 that extends from the opposite side of the final gear F from the perspective of the transmission gear 511 to above the transmission gear 511, with its tip 46a located above its base end 46b. In the gear chamber S2, the area above the rib 46 is a catch tank 7 (oil catch tank) capable of capturing oil OL (lubricating oil). In rib 46, an intermediate rib 47 is provided that extends upward from between the tip 46a and the base 46b. The tip 47a of the intermediate rib 47 is located above the tip 46a of rib 46.

[0064] According to this embodiment, the space above the transmission gear 511 and diagonally above the first gear 521 can be effectively utilized to form the catch tank 7. The inside of the catch tank 7 is divided by an intermediate rib 47 into a main tank section 7A on the base end 46b side of the rib 46 and a sub-tank section 7B on the tip end 46a side. The sub-tank section 7B is located above the main tank section 7A. The sub-tank section 7B is located on the side (left side in Figure 3) into which the oil OL scooped up by the final gear F flows, rather than on the main tank section 7A. Therefore, when the amount of oil OL scooped up by the final gear F is small, such as when a vehicle equipped with the drive unit 1 is traveling at a low speed, the oil OL that flows into the catch tank 7 will be captured in the sub-tank section 7B before the main tank section 7A. Furthermore, since the sub-tank section 7B has a smaller volume than the main tank section 7A, the oil OL captured in the sub-tank section 7B overflows from the tip 46a of the rib 46 forming the sub-tank section 7B, lubricating the transmission gear 511 located directly below it and the meshing portion E1 between the transmission gear 511 and the first gear 521. As a result, even if the amount of oil OL scooped up by the final gear F is small, the meshing portion E1 between the transmission gear 511 and the first gear 521 can be properly lubricated.

[0065] In other words, during low-speed driving where lubrication of the meshing portion E1 is required, the oil OL is captured in the small-capacity sub-tank 7B and overflows, allowing the transmission gear 511 located below the sub-tank 7B and the meshing portion E1 between the transmission gear 511 and the first gear 521 to be quickly lubricated. In Patent Document 1, when adjusting the supply timing of the oil (lubricating oil) captured in the oil catch tank, it is necessary to adjust the balance between the load of the captured lubricating oil and the force of the compression coil. Therefore, it is necessary to adjust the balance between the load of the captured lubricating oil and the force of the compression coil in advance, not only through calculations of force balance but also through experiments and simulations. In contrast, the drive device 1 according to the embodiment allows for the appropriate adjustment of the supply timing of the oil OL captured in the catch tank 7 to the meshing portion E1 (the part to be lubricated) with a simple configuration, while maintaining the capacity of the catch tank 7 without employing a complex mechanism.

[0066] (2) When viewed from the direction of axis X1, which is the rotation axis direction of the input shaft 51, the tip 46a side of the rib 46 forms an arc shape along the outer circumference of the transmission gear 511. The intermediate rib 47 extends upward from the second region 462, which is the arc-shaped region of the rib 46.

[0067] According to this embodiment, the second region 462 of the rib 46 can be positioned closer to the transmission gear 511. This ensures sufficient volume in the catch tank 7 and allows the captured oil OL to be appropriately supplied to the areas that need lubrication. Furthermore, by providing an intermediate rib 47 in the second region 462 of the rib 46, the sub-tank section 7B can be positioned on the oil OL inflow side of the catch tank 7, rather than on the main tank section 7A. This allows the oil OL to be captured in the sub-tank section 7B when the vehicle equipped with the drive unit 1 is traveling at low speed or immediately after starting to travel, when the amount of oil OL scooped up by the final gear F is small, and used for lubrication of the meshing portion E1 between the transmission gear 511 and the first gear 521.

[0068] Furthermore, since the capacity of the main tank section 7A is greater than the capacity of the sub-tank section 7B, when a vehicle equipped with the drive unit 1 is traveling at high speed, more oil OL can be captured in the main tank section 7A, reducing the amount of oil OL remaining at the bottom of the gear chamber S2. If the amount of oil OL remaining in the gear chamber S2 increases, the oil OL remaining at the bottom of the gear chamber S2 can create resistance to the rotation of the differential mechanism 6 (differential case DEF, final gear F), potentially affecting the efficiency of power transmission (rotational driving force) from the motor M to the drive wheels WH, WH. By capturing more oil OL in the main tank section 7A when a vehicle equipped with the drive unit 1 is traveling at high speed, the possibility of affecting power transmission efficiency can be reduced.

[0069] When a vehicle equipped with the drive unit 1 is running at low speed, the oil flow (overflow) from the sub-tank section 7B can quickly supply oil OL (lubricating oil) to parts that require lubrication. On the other hand, when running at high speed, the main tank section 7A captures a large amount of lubricating oil, thereby reducing the amount of unnecessary oil in the gear chamber S2. This makes it possible to achieve both lubrication and power transmission efficiency according to the driving conditions.

[0070] (3) The tip 46a of the rib 46 is the tip of the arc-shaped second region 462. When viewed from the direction of the axis X1 which is the rotation axis direction of the input shaft 51, the tip 46a of the rib 46 is positioned at a distance from the outer circumference of the first gear 521, facing the normal L2 passing through the meshing portion E1 between the transmission gear 511 and the first gear 521, at a position where the L2 crosses from the transmission gear 511 side to the first gear 521 side.

[0071] According to this embodiment, the meshing portion E1 between the transmission gear 511 and the first gear 521 can be properly lubricated.

[0072] (I) In the catch tank 7, one end 49a of the oil passage 49 opens into the main tank section 7A formed between the intermediate rib 47 and the base end 46b of the rib 46. The other end 49b of the oil passage 49 opens into the support section 411 of the bearing that rotatably supports the input shaft 51.

[0073] In this embodiment, the transmission gear 511 of the input shaft 51 is lubricated from the outer diameter side by oil OL overflowing from the sub-tank section 7B. Furthermore, the transmission gear 511 is also lubricated from the inner diameter side by oil OL supplied from the main tank section 7A via the oil passage 49. The oil OL captured by the catch tank 7 allows the transmission gear 511 to be properly lubricated from both the inner and outer diameter sides.

[0074] (4) The rib 46 has a width in the direction along the input shaft 51 (axis X1 direction). On the tip 46a side of the rib 46, there is a first side edge R1 along the tip 46a of the rib 46, and a second side edge R2 that is below the first side edge R1 and is oriented along the first side edge R1.

[0075] According to this embodiment, when the amount of oil OL flowing into the sub-tank section 7B is small, in the region of the sub-tank section 7B (catch tank 7) on the tip 46a side of the rib 46, the oil OL will overflow first from the region of the second side edge R2, which is located below the first side edge R1. Below the rib 46, the input shaft 51 (transmission gear 511) is located, and the input shaft 51 (transmission gear 511) is lubricated. Even when the amount of oil OL scooped up by the final gear F is small, such as when a vehicle equipped with the drive unit 1 is traveling at a low speed, proper lubrication can be performed around the input shaft 51.

[0076] (5) The first gear 521 and the second gear 522 are aligned in the direction of the rotation axis (axis X2 direction) of the intermediate shaft 52. When viewed from above (Z direction), the rib 46 is formed to span the first gear 521 and the second gear 522 in the direction of the rotation axis (axis X2) of the intermediate shaft 52. When viewed from above (Z direction), the boundary (connection region 482) between the first side edge R1 and the second side edge R2 is provided in a position that overlaps with the transmission gear 511.

[0077] According to the embodiment, in the second cover 4, which is a cast product, the lower surface of the rib 46 has a draft angle, and the lower surface of the rib 46 is lower on the first gear 521 side than on the second gear 522 side. Therefore, the oil OL that overflows from the second side edge R2 (straight region 481) travels along the lower surface of the rib 46, moves to the first side edge R1 side, and then falls into the gear chamber S2. The first side edge R1 overlaps with the transmission gear 511. Therefore, the oil OL that moves to the first side edge R1 side and then falls into the gear chamber S2 can properly lubricate the transmission gear 511 and the meshing portion E1 between the transmission gear 511 and the first gear 521. Thus, even when the amount of oil OL scooped up by the final gear F is small, such as when a vehicle equipped with the drive unit 1 is traveling at a low speed, the meshing portion E1 between the first gear 521 and the transmission gear 511 can be properly lubricated.

[0078] (6) The first gear 521 and the second gear 522 are located between a pair of side wall portions 41 and 21 that are spaced apart in the direction of rotation of the motor M. The rib has a rib 46 (first rib) which is integrally formed with the side wall portion 41 located on the side of the first gear 521, and a rib 26 (second rib) which is integrally formed with the side wall portion 21 located on the side of the second gear 522. The second side edge portion R2 is provided on the rib 46.

[0079] With this configuration, the volume of the catch tank 7 can be secured, allowing for proper lubrication of the parts of the drive unit 1 that require lubrication.

[0080] (II) A guide wall portion 263 is provided at the tip 26a of the rib 26. The upper edge 263a of the guide wall portion 263 is located above the tip 27a of the intermediate rib 27.

[0081] According to this embodiment, when the amount of oil OL scooped up by the final gear F is small, the amount of oil OL captured in the sub-tank portion 7B on the rib 26 side moves along the guide wall portion 263 toward the rib 46 (recess 48) is greater than the amount that leaks out from the portion of the rib 26 (third side edge portion R3 in Figure 6). Therefore, more oil OL can be allowed to overflow from the recess 48 (straight region 481: second side edge portion R2 in Figure 6) and guided to the meshing portion E1 between the transmission gear 511 and the first gear 521.

[0082] The modified catch tank 7' is described below. Figures 8 and 9 illustrate the modified catch tank 7'. Figure 10 illustrates the operation of the modified catch tank 7'. In Figure 8, the area around the catch tank 7' of the second cover 4 is shown in an enlarged schematic. In Figure 9, the area in the housing HS where the catch tank 7' is provided is shown in an enlarged schematic cross-section when cut along the line A-A in Figure 8.

[0083] The space that functions as the catch tank 7 is formed between the second cover 4 and the motor case 2 when the second cover 4 is assembled to the motor case 2. The space that functions as the catch tank 7' in the modified version is also formed between the second cover 4 and the motor case 2. In the modified catch tank 7', only the shape of the rib 46A on the second cover 4 side differs from the shape of the rib 46 of the catch tank 7 described above. The shape of the rib 46A on the second cover 4 side will be described in detail below.

[0084] As shown in Figure 8, in the second cover 4, the rib 46A protrudes from the side wall portion 41 toward the front of the paper (towards the motor case 2). The rib 46A has a first region 461, a second region 462, and a third region 463 (third rib). The rib 46A is formed by the first region 461, the second region 462, and the third region 463 being connected in series. The base end 46b of the first region 461 is connected to the inner circumference of the peripheral wall portion 42 between the horizontal line HL1 and the horizontal line HLa. The first region 461 extends substantially linearly from the inner circumference of the peripheral wall portion 42 along the horizontal line HL1 toward the transmission gear 511, and then connects to the lower end 462b of the second region 462. Viewed from the Y direction, the lower end 462b of the second region 462 is positioned to overlap with the transmission gear 511.

[0085] Viewed from the X direction, the second region 462 forms an arc shape that surrounds the outer circumference of the transmission gear 511 with gaps between them. The upper end 462a of the second region 462 connects to the third region 463 on the normal L2. The third region 463 extends along the normal L2 in a direction approaching the meshing portion E1 between the transmission gear 511 and the first gear 521 (diagonally downward in the figure). The third region 463 extends in a substantially straight line along the normal L2. The third region 463 is formed with a thickness W463 that crosses the normal L2 in the vertical direction.

[0086] The tip 463a of the third region 463 faces the meshing portion E1 from the direction of the normal L2, with a gap between it and the meshing portion E1. In this embodiment, the third region 463 has a length in the direction of the normal L2, with the tip 463a extending to the intersection of the vertical line VL1 and the normal L2. The tip 463a of the third region 463 is positioned to overlap the first gear 521 and offset from the transmission gear 511 when viewed from the Y direction. Furthermore, the tip 463a of the third region 463 is positioned to offset from the first gear 521 and overlap the transmission gear 511 when viewed from the Z direction.

[0087] In rib 46A, an intermediate rib 47A is provided between the upper end 462a and the lower end 462b in the second region 462. The intermediate rib 47A extends upward from a position where it intersects with the vertical line VL1a in the second region 462.

[0088] The intermediate rib 47A extends diagonally upward in the direction away from the first gear 521 (to the right in the figure). The tip 47a of the intermediate rib 47A is curved such that the tip 47a points upward. The region of the intermediate rib 47A on the tip 47a side of the curved portion 471 is approximately parallel to the vertical line VL1. The tip 47a of the intermediate rib 47A is located above the upper end 462a of the second region 462, specifically, above the uppermost upper edge 462c in the second region 462, by a height h1.

[0089] The upper surface 472 of the intermediate rib 47A is inclined such that the tip 47a is positioned higher than the base 47b (second region 462 side). Oil OL, which has been scraped up by the final gear F and passed between the first gear 521 and the peripheral wall 42 to reach the catch tank 7', collides with the upper surface 472 from above the first gear 521 (upper left in the figure). The inclination of the upper surface 472 is set so that the direction of movement of the oil OL that collides with the upper surface 472 can be changed from downward towards the transmission gear 511 (downper right in the figure) to upward away from the transmission gear 511 (upper right in the figure).

[0090] The peripheral wall portion 42 of the second cover 4 is provided with a projection 421 that protrudes downward toward the rib 46A side. When viewed from the Z direction, the projection 421 is positioned to overlap the region on the upper end 462a side of the second region 462 of the rib 46A. As a result, the oil OL moving toward the catch tank 7' through the space between the first gear 521 and the peripheral wall portion 42 is prevented from moving toward the tip 47a side of the intermediate rib 47A by the projection 421. Consequently, much of the oil OL moving toward the catch tank 7' collides with the upper surface 472 of the intermediate rib 47A at the base end 47b side of the intermediate rib 47A.

[0091] In this embodiment, the intermediate rib 47A is formed such that the thickness W47 increases towards the base end 47b in the curved portion 471 to the base end 47b. This increases the rigidity of the intermediate rib 47A to which the oil OL supplied from above on the first gear 521 side collides.

[0092] As shown in Figure 9, a recess 48 is also provided in rib 46A. Viewed from the Z direction, the recess 48 is formed as a recess on the intermediate rib 47A side (upper side in the figure). In rib 46A, the recess 48 is provided in a predetermined range in the X direction from the joint surface with rib 26 on the motor case 2 side. Viewed from the Z direction, the recess 48 has a linear region 481 (second side edge R2) that is substantially parallel to the upper end 462a (first side edge R1) of the second region 462, and a connecting region 482 that connects the linear region 481 and the upper end 462a of the second region 462. Viewed from the Z direction, the linear region 481 is positioned offset from the upper end 462a of the second region 462 toward the intermediate rib 47A. The aforementioned third region 463 (third rib) is connected to the upper end 462a of the second region 462. The third region 463 is not connected to the portion of the linear region 481. The third region 463 is connected to the region in the second region 462 where the recess 48 is not provided (the region at the upper end 462a). Here, the region along the upper end 462a of the second region 462 corresponds to the "first side edge" in the invention, and the region along the straight region 481 of the recess 48 corresponds to the "second side edge" in the invention.

[0093] As shown in Figure 8, when viewed from the X direction, the straight region 481 (second side edge) is located between the upper end 462a (first side edge) of the second region 462 and the intermediate rib 47A. Furthermore, the upper edge 481a of the straight region 481 is located below the upper edge 462c on the upper end 462a side of the second region 462. Therefore, as shown in Figure 9, in the sub-tank section 7B of the catch tank 7', more oil OL can be temporarily stored in the area of ​​the second region 462 of the rib 46A where the recess 48 is not provided (the area to the left of the connection region 482 in the figure) than in the area where the recess 48 is provided (the area to the right of the connection region 482 in the figure).

[0094] Furthermore, the oil OL stored in the area of ​​the second region 462 where the recess 48 is not provided is discharged towards the meshing portion E1 side along the upper surface of the third region 463 after passing the upper end 462a at the boundary with the third region 463. In addition, the oil OL stored in the area of ​​the second region 462 of the rib 46A where the recess 48 is provided is discharged to the outside of the sub-tank portion 7B from the straight region 481. In this embodiment, the upper end 462a of the second region 462 is located above the straight region 481 in the Z direction (see Figure 8). Therefore, the residence time of the oil OL captured in the area of ​​the second region 462 where the recess 48 is not provided in the sub-tank portion 7B is longer than the residence time of the oil OL captured in the area of ​​the second region 462 where the recess 48 is provided in the sub-tank portion 7B.

[0095] Here, we will explain the operation of the catch tank 7'. The oil OL that is stirred up by the final gear F (output shaft gear) contains a lot of air (bubbles). The sub-tank section 7B of the catch tank 7' is supplied with oil containing many bubbles from above on the side of the first gear 521.

[0096] As shown in Figure 10, the peripheral wall portion 42 of the second cover 4 is provided with a projection 421 that protrudes downward toward the rib 46A side. This projection 421 prevents the oil OL moving toward the catch tank 7' through the space between the first gear 521 and the peripheral wall portion 42 from moving toward the tip 47a side of the intermediate rib 47A. As a result, much of the oil OL moving toward the catch tank 7' collides with the upper surface 472 of the intermediate rib 47A at the base end 47b side of the intermediate rib 47A and is captured by the sub-tank portion 7B.

[0097] Here, the air bubbles contained in the oil OL tend to separate into upper and lower sections depending on the density of the bubbles. For example, oil OL with fewer bubbles and higher density moves to the lower side in the direction of gravity, while oil OL with many bubbles and lower density moves to the upper side in the direction of gravity.

[0098] Therefore, in the oil OL that collides with the upper surface 472 of the intermediate rib 47A and then moves along the upper surface 472 towards the tip 47a of the intermediate rib 47A, the oil OL tends to separate during its movement into an upper layer containing many bubbles due to the buoyancy of the bubbles, and a lower layer containing fewer bubbles and a higher density. In other words, it tends to separate into a supernatant oil OL containing many bubbles and a low density, and a lower layer of oil OL containing fewer bubbles and a high density. The sub-tank section 7B is continuously supplied with oil OL that has been scooped up by the final gear F when the vehicle equipped with the drive unit 1 is moving forward. Therefore, of the oil OL captured in the sub-tank section 7B, the supernatant oil OL containing many bubbles that has reached the tip 47a of the intermediate rib 47A is discharged into the main tank section 7A by overcoming the tip 47a of the intermediate rib 47A. This makes it possible to reduce the amount of bubbles in the oil OL remaining in the sub-tank section 7B (reduce the bubble content).

[0099] On the other hand, of the oil OL captured in the sub-tank section 7B, the lower layer of oil OL with a low air bubble content will remain in the sub-tank section 7B. As described above, the second region 462 of the sub-tank section 7B has a region with a recess 48 and a region without a recess 48. The region with a recess 48 can store less oil OL than the region without a recess 48. Furthermore, the straight region 481 (second side edge) of the region with a recess 48 is located lower than the upper end 462a (first side edge) of the region without a recess 48. Therefore, of the oil OL captured in the sub-tank section 7B, the oil OL that remains in the region with a recess 48 is discharged to the outside of the sub-tank section 7B from the straight region 481 (second side edge) before the oil that remains in the region without a recess 48.

[0100] Here, the amount of air bubbles contained in the oil OL tends to decrease over time. Therefore, as the oil OL trapped in the area where the recess 48 is not provided overflows over the upper end 462a of the second region 462 towards the third region 463, the amount of air bubbles contained in the oil decreases. As a result, the oil OL that overflows over the upper end 462a (first side edge) of the second region 462 towards the third region 463 (third rib) has a lower air bubble content than the oil OL that overflows and falls from the straight region 481 (second side edge). In other words, the air bubble content in the oil OL supplied to the meshing portion E1 via the surface of the third region 463 can be reduced.

[0101] Here, if the oil OL supplied to the meshing portion E1 contains a large amount of air bubbles, the apparent viscosity of the oil OL decreases, making it difficult to form a strong oil film on the surfaces of the transmission gear 511 and the first gear 512, which raises concerns about reduced lubricity. According to this embodiment, oil OL with a lower air bubble content can be supplied to the meshing portion E1, promoting the formation of a strong oil film and ensuring lubricity more reliably. Furthermore, since the third region 463 is formed with a thickness W463 that crosses the normal L2, the oil OL that has moved along the upper surface of the third region 463 to the tip 463a is supplied to the meshing portion E1 from above the normal L2 (see arrow IN in the figure). The rotation direction of the transmission gear 511 and the first gear 521 that mesh at the meshing portion E1 is such that the oil OL that lubricated the meshing portion E1 is scattered toward the third region 463 side of the rib 46A. In this process, the direction of movement of the scattered oil OL is initially along the normal L2, but as it moves away from the meshing portion E1, gravity causes it to change to a downward direction away from the normal L2 (see arrow OUT in the figure). Therefore, the possibility of interference between the oil OL (arrow IN) traveling towards the meshing portion E1 through the upper surface of the third region 463 and the oil OL (arrow OUT) scattered from the meshing portion E1 is reduced. As a result, the possibility of the supply of oil OL from the third region 463 to the meshing portion E1 being obstructed by the oil OL scattered from the meshing portion E1 is reduced, and the meshing portion E1 can be properly lubricated.

[0102] Furthermore, as shown in Figure 9, the third region 463 (third rib), viewed from the Z direction, is provided in a range that crosses the transmission gear 511 and the first gear 521 in the rotation axis direction (axis X2 direction: X direction) of the intermediate shaft 52. That is, viewed from the Z direction, the tip 463a of the third region 463 is positioned to overlap the transmission gear 511, and the linear region 481 (second side edge) is positioned to be offset from the transmission gear 511 and the first gear 521 in the rotation axis direction (axis X1 direction). This allows for the selective supply of oil OL, which has a low bubble content and high cooling performance, to the meshing portion E1 between the transmission gear 511 and the first gear 521, and prevents the supply of oil OL, which has a high bubble content and low cooling performance, to the meshing portion E1 between the transmission gear 511 and the first gear 521. Thus, the meshing portion E1 between the transmission gear 511 and the first gear 521 can be properly lubricated.

[0103] As described above, the drive unit 1 equipped with the modified catch tank 7' has the following configuration: (1) The drive unit 1 comprises a motor M which is a drive source, a power transmission mechanism 5 which transmits the power (rotational driving force) of the motor M to the drive wheels WH, WH, and a housing HS (case) which houses the motor M and the power transmission mechanism 5. The power transmission mechanism 5 includes an input shaft 51 to which power is input from a motor M; an intermediate shaft 52 to which the power input to the input shaft 51 is transmitted; drive shafts DS, DS (output shafts) to which the power transmitted to the intermediate shaft 52 is transmitted; a transmission gear 511 (input shaft gear) provided on the input shaft 51; a final gear F (output shaft gear) involved in the transmission of power to the drive shafts DS, DS (output shafts); a first gear 521 (first intermediate shaft gear) provided on the intermediate shaft 52 and rotatably meshing with the transmission gear 511; and a second gear 522 (second intermediate shaft gear) provided on the intermediate shaft 52 and rotatably meshing with the final gear F. The housing HS (case) has a gear chamber S2 which is the housing portion of the power transmission mechanism 5. In the gear chamber S2, the intermediate shaft 52 is located between the axis (axis X1) of the input shaft 51 and the axis (axis X3) of the drive shaft DS and DS (output shaft) in the Y direction, as viewed from the axial direction (axis X1 direction) of the input shaft 51. The axis (axis X2) of the intermediate shaft 52 is located above the axis (axis X1) of the input shaft 51 and the axis (axis X3) of the drive shaft DS and DS (output shaft). As viewed from the axial direction of the input shaft 51, axis X1 direction, the gear chamber S2 is provided with a rib 46A that extends from the opposite side of the final gear F from the perspective of the transmission gear 511 to above the transmission gear 511, and the tip 463a of the third region 463 is located above the base end 46b. In the gear chamber S2, the area above the rib 46A (first region 461, second region 462) is a catch tank 7' (oil catch tank) capable of capturing oil OL (lubricating oil). The rib 46A is provided with an intermediate rib 47A extending upward from between the upper end 462a and lower end 462b of the second region 462. The tip 47a of the intermediate rib 47A is located above the upper edge 462c of the second region 462 of the rib 46A.

[0104] According to this embodiment, the space above the transmission gear 511 and diagonally above the first gear 521 can be effectively utilized to form the catch tank 7'. The interior of the catch tank 7' is divided by an intermediate rib 47A into a main tank section 7A on the base end 46b side of the rib 46A and a sub-tank section 7B on the upper end 462a side of the second region 462. The sub-tank section 7B is located above the main tank section 7A. Furthermore, the sub-tank section 7B is located on the side (left side in Figure 8) into which the oil OL (lubricating oil) scraped up by the final gear F flows, compared to the main tank section 7A. Therefore, when the amount of oil OL scraped up by the final gear F is small, such as when a vehicle equipped with the drive unit 1 is traveling at a low speed, the oil OL that flows into the catch tank 7' will be captured in the sub-tank section 7B before the main tank section 7A. Furthermore, since the sub-tank section 7B has a smaller volume than the main tank section 7A, the oil OL captured in the sub-tank section 7B overflows from the upper end 462a of the rib 46A forming the sub-tank section 7B, lubricating the transmission gear 511 located directly below it and the meshing portion E1 between the transmission gear 511 and the first gear 521. As a result, even if the amount of oil OL scooped up by the final gear F is small, the meshing portion E1 between the transmission gear 511 and the first gear 521 can be properly lubricated.

[0105] In Patent Document 1, when adjusting the supply timing of the oil (lubricating oil) captured in the oil catch tank, it is necessary to adjust the timing so that the load of the captured lubricating oil and the force of the compression coil are balanced. Therefore, it is necessary to pre-adjust the balance between the load of the captured lubricating oil and the force of the compression coil not only through calculations of force balance, but also through experiments and simulations. In contrast, the drive device 1 according to the embodiment can appropriately adjust the supply timing of the oil OL captured in the catch tank 7' to the meshing part E1 (lubrication target area) with a simple configuration, while maintaining the capacity of the catch tank 7' without employing a complex mechanism.

[0106] (7) The rib 46A has a third region 463 (third rib) extending from the upper end 462a of the second region 462. Viewed from the axial direction of the input shaft 51 (axis X1 direction), the third region 463 extends from the upper end 462a of the second region 462 in a direction toward the meshing portion E1 along the normal L2 that passes through the meshing portion E1 between the transmission gear 511 (input shaft gear) and the first gear 521 (first intermediate shaft gear). The tip 463a of the third region 463 faces the meshing portion E1 with a gap between them.

[0107] With this configuration, at the tip of the rib 46A, a portion of the oil OL trapped in the region between the rib 46A and the intermediate rib 47A (sub-tank portion 7B) moves downward along the upper surface of the third region 463 towards the meshing portion E1, and then falls from the tip 463a of the third region 463 towards the meshing portion E1. As a result, the heat generated at the meshing portion E1 between the transmission gear 511 and the first gear 521 can be cooled by the oil OL supplied from the third region 463 towards the meshing portion E1. In addition, the oil OL supplied to the transmission gear 511 and the first gear 521 contributes to the lubrication of the transmission gear 511 and the first gear 521 until they reach the next meshing position, reducing friction during the next meshing, and thus suppressing heat generation at the meshing portion E1.

[0108] Here, the oil OL that the final gear F has scooped up and reached the catch tank 7' is temporarily stored in the sub-tank section 7B. At this time, the oil OL captured in the sub-tank section 7B tends to separate into oil OL with a high density and a large amount of air bubbles, and oil OL with a high density and fewer air bubbles. By temporarily storing the oil OL in the sub-tank section 7B, the oil OL that overflows from the sub-tank section 7B and falls toward the meshing section E1 can be made into oil OL with a lower air bubble content and a higher density. Since oil OL with a high density has better cooling performance than oil OL with a low density, supplying oil OL with a high density to the meshing section E1 allows for more appropriate cooling of the meshing section E1, the transmission gear 511, and the first gear 521.

[0109] Furthermore, oil OL containing many air bubbles and having low density will be largely contained in the supernatant of oil OL captured in the sub-tank section 7B. Therefore, when the amount of oil OL captured in the sub-tank section 7B increases, the oil OL containing many air bubbles and having low density will overflow the tip 47a of the intermediate rib 47A and be discharged to the outside of the sub-tank section 7B. Here, in the catch tank 7', the sub-tank section 7B and the main tank section 7A are adjacent with the intermediate rib 47A in between. The oil OL that overflows the tip 47a of the intermediate rib 47A is collected in the main tank section 7A. As a result, the oil OL with a low air bubble content and high density is left in the sub-tank section 7B and overflows from the third region 463, thereby supplying oil OL with high density and high cooling performance to the meshing section E1.

[0110] (8) The rib 46A has a width in the axial direction of the input shaft 51 (axis X1 direction) (see Figure 9). At the tip of the rib 46A, there is an upper end 462a of the second region 462 which is the first side edge along the input shaft 51, and a straight region 481 (second side edge) which is provided below the upper end 462a on the intermediate rib 47A side and is oriented along the upper end 462a. The third region 463 (third rib) is connected to the upper end 462a of the second region 462.

[0111] With this configuration, when viewed from the axial direction of the input shaft 51 (axis X1 direction), the linear region 481 (second side edge) is positioned below the connection between the third region 463 and the first side edge of the second region 462. The oil OL that is scraped up by the final gear F (output shaft gear) and captured in the sub-tank section 7B is more easily discharged from the region where the linear region 481 (second side edge) is provided. Here, the oil OL scraped up by the output shaft gear contains many air bubbles. The air bubbles contained in the oil OL become easier to separate from the oil OL over time. Of the oil OL captured in the sub-tank section 7B, the oil OL captured between the upper end 462a (first side edge) of the second region 462 and the intermediate rib 47A has a longer residence time in the sub-tank section 7B than the oil OL captured between the linear region 481 (second side edge) and the intermediate rib 47A. Therefore, the oil OL that overflows beyond the upper end 462a (first side edge) of the second region 462 and flows towards the third region 463 (third rib) has a lower bubble content than the oil OL that overflows and falls from the straight region 481 (second side edge). In other words, the bubble content in the oil OL supplied to the meshing portion E1 via the surface of the third region 463 can be reduced.

[0112] Here, if the oil OL supplied to the meshing portion E1 contains a large amount of air bubbles, it tends to become difficult for a film of oil OL to form on the surfaces of the transmission gear 511 and the first gear 521, raising concerns about reduced lubricity. By supplying oil OL with a lower air bubble content to the meshing portion E1, lubricity can be ensured. In addition, the oil OL captured in the sub-tank portion 7B tends to separate into upper and lower sections depending on the density of the air bubbles and the passage of time. For example, oil OL with fewer air bubbles and higher density (high cooling performance) moves to the lower side, while oil OL with many air bubbles and lower density (low cooling performance) moves to the upper side. As a result, the amount of air bubbles contained in the oil OL captured between the upper end 462a (first side edge) of the second region 462 and the intermediate rib 47A can be reduced before it crosses the connection portion with the third region 463 and moves to the third region 463 side. Therefore, the air content in the oil OL supplied from the third region 463 to the meshing portion E1 can be reduced. On the other hand, the oil OL trapped between the straight region 481 (second side edge) and the intermediate rib 47A is discharged outside the sub-tank portion 7B in a shorter time because the straight region 481 (second side edge) is located below the upper end 462a of the second region 462. As a result, oil OL with a low air bubble content (low content) and high cooling performance can be supplied to the meshing portion E1 from the oil OL trapped in the sub-tank portion 7B.

[0113] (9) The first gear 521 and the second gear 522 are aligned in the direction of the rotation axis (axis X2 direction) of the intermediate shaft 52. When viewed from above, the third region 463 (third rib) is provided in the area that crosses the first gear 521 in the direction of the rotation axis (axis X2 direction) of the intermediate shaft 52.

[0114] With this configuration, when viewed from the Z direction, the tip 463a (first side edge) of the third region 463 is positioned to overlap with the transmission gear 511, while the linear region 481 (second side edge) is positioned to be offset from the transmission gear 511 and the first gear 521 in the direction of the rotation axis (axis X1 direction) (see Figure 9). This allows for the selective supply of oil OL, which has a low bubble content and high cooling performance, to the meshing portion E1 between the transmission gear 511 and the first gear 521, while preventing the supply of oil OL, which has a high bubble content and low cooling performance, to the meshing portion E1 between the transmission gear 511 and the first gear 521. Thus, the meshing portion E1 between the transmission gear 511 and the first gear 521 can be properly lubricated.

[0115] Here, the forms of the ribs 26, 46 and intermediate ribs 27, 47 are not limited to those illustrated in the embodiments and modifications. For example, they may include the following forms: (1) Ribs whose cross-section is rectangular, trapezoidal, triangular, arcuate, or a combination thereof; (2) Ribs whose tips are chamfered or curved, or flat; (3) Ribs whose height or width gradually increases / decreases from the base to the tip; (4) Ribs that are linear, arcuate, bent, or partially curved; (5) Intermediate ribs formed one or more at arbitrary positions along the longitudinal direction of the rib; (6) Intermediate ribs whose upper surface is horizontal, inclined, or curved to control the direction of lubrication; (7) Ribs or intermediate ribs that abut against a mating member or face each other with a predetermined gap between them.

[0116] Even in this configuration, the ribs create a region where lubricating oil can be captured. Furthermore, the intermediate ribs can adjust the timing or direction of the retention and overflow of the captured oil.

[0117] By employing the catch tank 7 according to the above embodiment or the catch tank 7' according to a modified example, the supply timing of the oil OL (lubricating oil) captured by the catch tanks 7 and 7' can be appropriately adjusted with a simple configuration of ribs 46, 46A and intermediate ribs 47, 47A, which are preferably integrally formed on the housing HS (case).

[0118] Although embodiments of the present invention have been described above, these embodiments are merely examples of how the present invention can be applied, and are not intended to limit the technical scope of the present invention to the specific configurations of these embodiments. Modifications can be made as appropriate within the scope of the technical concept of the invention.

[0119] 1: Drive unit, 5: Power transmission mechanism, 21: Side wall, 26: Rib (second rib), 26a: Tip, 26b: Base, 262: Second region (arc-shaped region), 27: Intermediate rib, 27a: Tip, 41: Side wall, 46, 46A: Rib (first rib), 46a: Tip, 46b: Base, 462: Second region (arc-shaped region), 462a: Upper end (first side edge), 463: Third region (third rib), 47, 47A: Intermediate rib, 47a: Tip, 481: Straight region (second side edge), 51: Input shaft, 511: Transmission gear (input shaft gear), 52: Intermediate shaft, 521: First gear (first intermediate shaft gear), 522: Second gear (second intermediate shaft gear), 7, 7': Catch tank (oil catch tank), DS: Drive shaft (output shaft), E1, E2: Meshing part, F: Final gear (output shaft gear), HS: Housing (case), M: Motor, S2: Gear chamber (housing part of power transmission mechanism), WH: Drive wheel, R1: First side edge, R2: Second side edge, X1: Axis (axis of input shaft), X2: Axis (axis of intermediate shaft), X3: Axis (axis of output shaft)

Claims

1. A drive device comprising: a motor; a power transmission mechanism for transmitting power from the motor to a drive wheel; and a case for housing the motor and the power transmission mechanism, wherein the power transmission mechanism comprises: an input shaft to which power from the motor is input; an intermediate shaft to which power input to the input shaft is transmitted; an output shaft to which power transmitted to the intermediate shaft is transmitted; an input shaft gear provided on the input shaft; an output shaft gear provided on the output shaft; a first intermediate shaft gear provided on the intermediate shaft and rotatably meshing with the input shaft gear; and a second intermediate shaft gear provided on the intermediate shaft and rotatably meshing with the output shaft gear, wherein the case has a housing portion for the power transmission mechanism, and in the housing portion, the intermediate shaft is located between the input shaft and the output shaft when viewed from the axial direction of the input shaft, and the axis of the intermediate shaft is located above the axis of the input shaft and the axis of the output shaft. A drive device is provided with a rib that extends from the opposite side of the input shaft gear to the output shaft gear as viewed from the input shaft gear, up to the top of the input shaft gear, with its tip positioned above its base end, and the part above the rib serving as a catch tank capable of capturing lubricating oil, and the rib is provided with an intermediate rib that extends upward from between its tip and base end, with the tip of the intermediate rib positioned above the tip of the rib.

2. The drive device according to claim 1, wherein, when viewed from the axial direction of the input shaft, the tip of the rib forms an arc shape along the outer circumference of the input shaft gear, and the intermediate rib extends upward from the arc-shaped region.

3. The drive device according to claim 2, wherein the tip of the rib is the tip of the arc-shaped region, and, viewed from the axial direction of the input shaft, the tip of the rib faces the outer circumference of the first intermediate shaft gear at a distance from the input shaft gear side, at a position where the normal passing through the meshing portion between the input shaft gear and the first intermediate shaft gear intersects from the input shaft gear side to the first intermediate shaft gear side.

4. The drive device according to claim 2, wherein the rib has a width in the direction along the input shaft, and the tip side of the rib is provided with a first side edge portion along the tip of the rib and a second side edge portion provided below the first side edge portion and in the direction along the first side edge portion.

5. The drive device according to claim 4, wherein the first intermediate shaft gear and the second intermediate shaft gear are aligned in the direction of the rotation axis of the intermediate shaft, the rib is provided in a range that crosses the first intermediate shaft gear and the second intermediate shaft gear in the direction of the rotation axis of the intermediate shaft when viewed from above, and the boundary between the first side edge and the second side edge is provided in a position that overlaps with the input shaft gear when viewed from above.

6. The drive device according to claim 5, wherein the first intermediate shaft gear and the second intermediate shaft gear are located between a pair of side wall portions that are spaced apart in the direction of rotation of the intermediate shaft, the rib has a first rib integrally formed with the side wall portion of the pair of side wall portions located on the side of the first intermediate shaft gear, and a second rib integrally formed with the side wall portion of the pair of side wall portions located on the side of the second intermediate shaft gear, and the second side edge portion is provided on the first rib.

7. The drive device according to claim 3, having a third rib extending from the tip of the rib, wherein, viewed from the axial direction of the input shaft, the third rib extends from the tip of the rib in a direction toward the meshing portion along a normal passing through the meshing portion between the input shaft gear and the first intermediate shaft gear, and the tip of the third rib faces the meshing portion with a gap between them.

8. The drive device according to claim 7, wherein the rib has a width in the direction along the input shaft, the tip side of the rib is provided with a first side edge along the input shaft and a second side edge provided below the first side edge on the intermediate rib side and in the direction along the first side edge, and the third rib is connected to the first side edge of the rib.

9. The drive device according to claim 8, wherein the first intermediate shaft gear and the second intermediate shaft gear are aligned in the direction of the rotation axis of the intermediate shaft, and the third rib, when viewed from above, is provided in a range that crosses the first intermediate shaft gear in the direction of the rotation axis of the intermediate shaft.

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