Drive device
Patent Information
- Application Number
- PCT/JP2026/011695
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-26
- Filing Date
- 2026-03-24
- Publication Date
- 2026-10-01
Smart Images
Figure JP2026011695_01102026_PF_FP_ABST
Abstract
Description
Drive device
[0001] The present invention relates to a drive device.
[0002] Patent Document 1 discloses a vehicle drive device that can adjust the time required for supplying lubricating oil captured in an oil catch tank to a lubrication site.
[0003] Japanese Unexamined Patent Application Publication No. 2010-174961
[0004] The oil catch tank of Patent Document 1 includes a variable capacity device that increases or decreases the capacity of a tank portion that stores lubricating oil. The variable capacity 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 at substantially the same height as the lower side of the lubricating oil discharge port and a second oil level position higher than the first oil level position.
[0005] For example, when a vehicle equipped with a vehicle drive device starts from a stopped state, by setting the capacity of the tank portion to the minimum capacity state, the time required for the oil level of the captured oil to exceed the height of the lubricating oil discharge port is shortened. This makes it possible to shorten the time required for the lubricating oil flowing into the lubricating oil discharge port to be supplied to the supply destination of the lubricating oil, so that the supply destination of the lubricating oil can be properly lubricated in a situation where lubricating oil tends to be insufficient immediately after starting.
[0006] In the case of Patent Document 1, among the oil captured in the tank portion, the oil overflowing from the tank portion falls below the tank portion and lubricates the meshing portion (meshing part) between gears located below the tank portion. However, depending on the operating state of a vehicle equipped with the vehicle drive device, lubrication of the meshing portion (meshing part) between gears may be insufficient, and there is a demand for enabling more appropriate lubrication of the meshing portion (meshing part) between gears.
[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, viewed from the axial direction of the input shaft, the housing portion is provided with a scraping rib having height in the axial direction of the input shaft below the first intermediate shaft gear. The drive device is configured such that, when viewed from the axial direction of the input shaft, the lower end of the scraping rib is located on the output shaft side of the axis of the intermediate shaft, and the upper end of the scraping rib is located on the input shaft side of the axis of the intermediate shaft and above the lower end of the input shaft gear.
[0008] According to one aspect of the present invention, the meshing parts of gears can be lubricated more effectively.
[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 an enlarged view of the main part of the second cover. Figure 4 is a cross-sectional view of the main part of the second cover. Figure 5 is a diagram illustrating the function of the ribs. Figure 6 is a diagram illustrating the function of the ribs. Figure 7 is a diagram illustrating the ribs in a modified example.
[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] "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.
[0012] "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.
[0013] 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 statement in the specification explaining that the first element is located between the second and third elements in a predetermined viewing direction.
[0014] "Axial direction" refers to the axial direction 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.
[0015] 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.
[0016] In the following description, the vertical direction (direction of gravity) may be denoted by the symbol "Z", the vehicle 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 width direction. The Y direction is the horizontal direction perpendicular to the vertical line VL1 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 means the direction of the vertical line VL1 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. The main component in the embodiments of the present invention is the drive unit, and the mounting on the vehicle in the figures is illustrative.
[0017] 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 housing 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.
[0018] 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.
[0019] 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.
[0020] 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.
[0021] 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.
[0022] 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.
[0023] 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.
[0024] 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.
[0025] 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.
[0026] 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.
[0027] 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.
[0028] 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.
[0029] Figure 3 is an enlarged view of the main part of the second cover 4. Figure 4 is a cross-sectional view of the main part of the second cover 4. In Figure 3, the area around the first region 43 in the second cover 4 where the input shaft 51 and intermediate shaft 52 are provided is schematically shown in an enlarged view. In Figure 4, the cross-section along the line A-B-C in Figure 3 is schematically shown.
[0030] As shown in Figure 2, in the gear chamber S2, a rib 46 (a scraping rib: a member that has the function of scraping up oil OL) is provided below the first gear 521 when viewed from the axial direction of the input shaft 51 (axis X1 direction: X direction). The rib 46 is provided in a range that crosses the vertical line VL2 passing through the axis of the intermediate shaft 52 from one side (final gear F side: left side in the figure) to the other side (input shaft 51 side: right side in the figure). The upper end 46a of the rib 46 is located above the lower end 46b in the Z direction. The upper end 46a of the rib 46 is on the input shaft 51 side of the vertical line VL2 and is located above the horizontal line HL1a passing through the lower end of the transmission gear 511. The upper end 46a of the rib 46 faces the outer circumference of the first gear 521 between the horizontal line HL1 and the horizontal line HL1a. The horizontal line HL1 is a horizontal line that passes through the axis (axis X1) of the input shaft 51.
[0031] As shown in Figure 3, the upper end 46a of the rib 46 is located below the normal L2. The normal L2 is a straight line perpendicular to the straight line L1 that passes through the meshing portion E1 between the transmission gear 511 and the first gear 521 and connects the axis of the input shaft 51 (axis X1) and the axis of the intermediate shaft 52 (axis X2). When viewed from the first gear 521, the normal L2 extends in the tangential direction through the meshing portion E1 with the transmission gear 511.
[0032] Viewed from the axial direction (axis X1 direction) of the input shaft 51, the rib 46 has an arc shape in a predetermined range from the upper end 46a to the lower end 46b that surrounds the outer circumference of the final gear F with a gap. As shown in Figure 2, this arc-shaped region 461 is located on a virtual circle Im1 centered on axis X3. The rib 46 has a bent portion 46c at a position offset from the lower end 46b. The region of the rib 46 on the lower end 46b side of the bent portion 46c extends downward in a direction along the vertical line VL1. The region of the rib 46 on the lower end 46b side of the bent portion 46c extends linearly in a direction away from the virtual circle Im1. The lower end 46b of the rib 46 faces the region 42A that forms the bottom wall of the gear chamber S2 in the peripheral wall portion 42, with a gap CL in the Z direction.
[0033] At the bottom of the gear chamber S2, oil OL (lubricating oil) for lubricating the components of the power transmission mechanism 5 is stored. 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 at the bottom 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 42. Then, after passing between the intermediate shaft 52 and the peripheral wall 42 and reaching the area where the input shaft 51 is provided, it falls to the bottom of the gear chamber S2 due to its own weight. The oil OL that has fallen to the bottom of the gear chamber S2 is then scraped up again by the final gear F. Here, if the amount of oil OL remaining at the bottom of the gear chamber S2 becomes large, the oil OL may become a resistance to the rotation of the differential mechanism 6 (differential case DEF, final gear F), potentially affecting the efficiency of transmitting the power (rotational driving force) of the motor M to the drive wheels WH, WH.
[0034] In this embodiment, when a vehicle equipped with the drive unit 1 is in motion, a rib 46 is provided diagonally to the lower right of the input shaft 51 side as viewed from the final gear F, in order to adjust the amount of oil OL moving toward the final gear F side in the lower part of the gear chamber S2. By setting a gap CL (the presence or absence of a gap, or a blocking means corresponding to the gap) between the lower end 46b of the rib 46 and the peripheral wall portion 42 (region 42A), the amount of oil OL returning from the lower region of the input shaft 51 in the gear chamber S2 to the region of the gear chamber S2 where the differential mechanism 6 is provided is adjusted. This reduces the resistance when the final gear F scoops up the oil OL.
[0035] As described above, in the intermediate shaft 52, the first gear 521 is located towards the back of the paper, while the second gear 522 is located towards the front of the paper. Therefore, the transmission gear 511 that meshes with the first gear 521 is also located towards the back of the paper than the final gear F that meshes with the second gear 522. As shown in Figure 3, the side wall portion 41 of the gear chamber S2 (the housing portion of the power transmission mechanism 5) has a first region 43 that covers the sides of the first gear 521 and the transmission gear 511, and a second region 44 that covers the side of the final gear F. When viewed from the direction of axis X1, the first region 43 is a region formed by recessing the area of the side wall portion 41 that overlaps with the input shaft 51 and the intermediate shaft 52 towards the back of the paper. The first region 43 is offset to the back of the paper by a predetermined depth h43 (see Figure 4) than the second region 44. In the second cover 4, the first region 43 is given depth in the direction of axis X1 so that the input shaft 51 and the intermediate shaft 52 can be housed in the gear chamber S2. The predetermined depth h43 is set based on experiments and other factors, such as the amount and flow velocity of the oil OL to be moved.
[0036] As shown in Figure 3, the boundary between the first region 43 and the second region 44 is formed by three circumferential wall sections (first circumferential wall section 431, second circumferential wall section 432, and third circumferential wall section 433) connected in series. The first circumferential wall section 431 is a substantially arc-shaped region surrounding the outer circumference of the first gear 521. The first circumferential wall section 431 is provided in an area extending from above the first gear 521 to the side of axis X3 (left side in the figure). The first circumferential wall section 431 crosses the vertical line VL2 from axis X1 (right side in the figure) to axis X3 (left side in the figure), and then connects to the second circumferential wall section 432 at a position where it crosses the horizontal line HL2 passing through the axis of the intermediate shaft 52 from top to bottom.
[0037] The second circumferential wall portion 432 extends linearly from the intersection point Pa of the diameter line L51a of the first gear 521 and the first circumferential wall portion 431, along the tangent line L4 of the first circumferential wall portion 431. The second circumferential wall portion 432 is inclined such that its height in the Z direction decreases as it approaches the vertical line VL2. The lower end of the second circumferential wall portion 432 connects to the third circumferential wall portion 433 near the horizontal line L47a that passes through the lower edge of the opening 47, which will be described later.
[0038] The third circumferential wall portion 433 has a substantially arc shape that surrounds the opening 47 at predetermined intervals. The third circumferential wall portion 433 bypasses the lower part of the opening 47 and extends from the axis X3 side to the axis X2 side, and connects to the rib 46 beyond the vertical line VL2. When viewed from the direction of axis X1, the rib 46 is tangent to the arc-shaped third circumferential wall portion 433. The predetermined interval between the third circumferential wall portion 433 and the opening 47 is set based on experiments, etc., from the amount and flow velocity of the oil OL to be moved.
[0039] Furthermore, a bulge 45 is provided in the region where the second peripheral wall portion 432 is located, bulging out in the direction approaching the first gear 521. As shown in Figure 4, the bulge 45 is formed with a predetermined height h45 in the X direction from the first region 43. The height h45 of the bulge 45 is smaller than the offset amount (h43) between the first region 43 and the second region 44. Therefore, as shown in Figure 3, when viewed from the X direction, the bulge 45 is located further back in the plane of the paper than the second region 44.
[0040] As shown in Figure 3, the bulging portion 45 has a shape on the surface facing the first gear 521 in which a first curved portion 451, a second curved portion 452, and a third curved portion 453 are connected in series. The first curved portion 451 is arc-shaped along the virtual circle Im2 that runs along the inner circumference of the first circumferential wall portion 431. The first curved portion 451 extends from the intersection point Pa of the diameter line L51a and the first circumferential wall portion 431 in a direction approaching the vertical line VL2 (to the right in the figure). The first curved portion 451 is connected to the second curved portion 452 at the intersection point Pb of the other diameter line L51b of the first gear 521 and the virtual circle Im2.
[0041] The third curved section 453 is arc-shaped, enclosing the opening 47 at predetermined intervals. The third curved section 453 bypasses the lower part of the opening 47 and extends from the axis X3 side to the axis X2 side. The axis X3 side (left side in the figure) of the third curved section 453 is connected to the second curved section 452 described above. The axis X2 side (right side in the figure) of the third curved section 453 is connected to the rib 46 beyond the vertical line VL2. When viewed from the direction of axis X1, the rib 46 is externally tangent to the arc-shaped third curved section 453. When viewed from the direction of axis X1, the third curved section 453 merges with the third peripheral wall section 433 described above below the straight line L3. The straight line L3 is a straight line that passes through the intersection point Pb of the diameter line L51b described above and the virtual circle Im2, and extends in the tangential direction of the first gear 521.
[0042] The third curved section 453 is located between the third peripheral wall section 433 and the opening 47. Viewed from the third curved section 453, the opening 47 side is a recess 48 that surrounds the opening 47 at predetermined intervals. As shown in Figure 4, the area of the recess 48 communicates with the first area 43 from below in the Z direction. The area of the recess 48 overlaps with the final gear F housed in the second area 44 in the X direction. Viewed from the X direction, the recess 48 is recessed away from the final gear F. In the recess 48, an opening 47 is provided that penetrates the side wall section 41 in the thickness direction. The opening 47 communicates the gear chamber S2 inside the second cover 4 with the outside of the second cover 4 (housing HS).
[0043] The opening 47 is an oil filling port for oil OL that is used when filling the housing HS with oil OL after the driving device 1 is shipped. Inside the housing HS, oil OL is always filled up to the height of the lower side of the opening 47. After oil OL is injected into the housing HS, a plug PL is screwed into the opening 47 from the outside of the housing HS to seal the opening 47. The plug PL used herein is such that when the opening 47 is sealed, the tip end PLa of the plug PL remains inside the opening 47 and does not protrude into the recess 48.
[0044] Figures 5 and 6 are diagrams explaining the action of the rib. In Figures 5 and 6, in order to make the position of the rib 46 easy to recognize, hatching crossing the end face of the rib 46 on the near side of the drawing is applied for illustration. As shown in Figure 2, when a vehicle equipped with the driving device 1 travels forward, part of the oil OL scraped up by the final gear F is drawn into the first gear 521 that rotates in the direction opposite to the rotation direction of the final gear F, and moves downward from the axis X3 side viewed from the axis X2. At this time, due to the pump effect caused by the rotating first gear 521, more oil OL is drawn in between the first gear 521 and the first peripheral wall portion 431. The drawn oil OL moves downward along the first peripheral wall portion 431.
[0045] Below the first peripheral wall portion 431, the linear second peripheral wall portion 432 along the tangent line L4 is provided with a bulging portion 45 that bulges from the tangent line L4 toward the vertical line VL2 side. Therefore, the flow of oil OL that has moved along the first peripheral wall portion 431 is split into a flow along the second peripheral wall portion 432 and a flow along the first curved portion 451 of the bulging portion 45 (see the arrows in Figure 4).
[0046] As shown in Figure 5, when the oil OL moving along the first curved section 451 reaches the second curved section 452, it spreads downward due to centrifugal force and moves along the straight line L3. As mentioned above, the upper end 46a of the rib 46 is provided across the straight line L3. Therefore, the oil OL moving along the straight line L3 collides with the region on the upper end 46a side of the rib 46 and its direction of movement is changed. The upper end 46a of the rib 46 is located below the normal L2 that passes through the meshing portion E1 between the first gear 521 and the transmission gear 511. Therefore, the direction of movement of the oil OL that collides with the region on the upper end 46a side of the rib 46 is changed to move closer to the axis X1 on the side of the direction of the upper end 46a of the rib 46 (upper right in the figure). As a result, much of the oil OL whose direction of movement has been changed after colliding with the region on the upper end 46a side of the rib 46 collides with the meshing portion E1 between the first gear 521 and the transmission gear 511 from below. As a result, the meshing portion E1 between the first gear 521 and the transmission gear 511 is lubricated by oil OL that collides with it from below. That is, the oil OL drawn into the first gear 521 moves along the straight line L3, collides with the upper end 46a of the rib 46, changes direction of movement, and is supplied to the meshing portion E1 from below.
[0047] On the other hand, as shown in Figure 6, when the oil OL moving along the second circumferential wall portion 432 reaches the region of the third circumferential wall portion 433, it flows along the third circumferential wall portion 433, changing its direction of movement to one that follows the region on the upper end 46a side of the rib 46. The upper end 46a of the rib 46 is below the normal L2 passing through the meshing portion E1 between the first gear 521 and the transmission gear 511, and faces the outer circumference of the first gear 521. Therefore, the direction of movement of the oil OL flowing along the region on the upper end 46a side of the rib 46 is changed to one that approaches the axis X1 on the side of the direction of the upper end 46a of the rib 46 (upper right in the figure). As a result, much of the oil OL flowing along the third circumferential wall portion 433 collides with the meshing portion E1 between the first gear 521 and the transmission gear 511 from below, lubricating the meshing portion E1.
[0048] Furthermore, a part of the oil OL flowing through the first curved portion 451 of the aforementioned bulging portion 45 moves along the second curved portion 452 and flows into the recess 48. The oil OL flowing into the recess 48 flows along the third curved portion 453, so that the moving direction is changed to a direction along the region on the upper end 46a side of the rib 46. Accordingly, the oil OL that has flowed into the recess 48 also collides from the lower side around the meshing portion E1 between the first gear 521 and the transmission gear 511, thereby lubricating the meshing portion E1. Note that the plug PL that closes the opening 47 provided in the recess 48 does not protrude into the recess 48 (see FIG. 4), so the flow of the oil OL along the inner periphery of the third curved portion 453 of the recess 48 is not obstructed.
[0049] FIG. 7 is a diagram illustrating a rib 46A according to a modified example. In the above-described embodiment, the case where the shape of the upper end 46a side of the rib 46 is an arc shape along the imaginary circle Im1 (see FIG. 2) is exemplified. The shape of the rib 46 is not limited to this embodiment. For example, as shown in FIG. 7, a bent portion 46d may be provided on the upper end 46a side, and a rib 46A including a linear extending portion 462 on the upper end 46a side of the bent portion 46d may be employed.
[0050] As shown in FIG. 7, in the rib 46A, the bent portion 46d is located within a region surrounded by vertical lines VL1, VL2, horizontal lines HL1, HL1a, and a normal line L2. The linear region (extending portion 462) on the upper end 46a side of the bent portion 46d extends from the normal line L2 to a position slightly offset downward in a direction approaching the meshing portion E1 along the normal line L2. The upper end 46a of the rib 46A faces the outer periphery of the transmission gear 511 from the direction of the normal line L2 at a position slightly offset downward from the horizontal line HL1.
[0051] As described above, when the oil OL moving along the first curved section 451 reaches the second curved section 452, it moves along the straight line L3 while spreading downward due to centrifugal force. The region of the arc-shaped region 461 of the rib 46A near the bent section 46d is provided crossing the straight line L3 from bottom to top. Therefore, the oil OL moving along the straight line L3 collides with the region of the rib 46A on the bent section 46d side and its direction of movement is changed. In the rib 46A, the extension 462 on the upper end 46a side of the bent section 46d extends slightly below the normal L2 passing through the meshing section E1 between the first gear 521 and the transmission gear 511, and moves in a direction toward the meshing section E1 along the normal L2. Therefore, the direction of movement of the oil OL that collides with the region of the rib 46A on the bent section 46d side is changed to a direction toward the extension 462 of the rib 46A. As a result, much of the oil OL that collides with the region on the bent portion 46d side of the rib 46A and has its direction of movement changed will collide with the meshing portion E1 between the first gear 521 and the transmission gear 511 from below, lubricating the area around the meshing portion E1. Similarly, the oil OL moving along the third circumferential wall portion 433 and the third curved portion 453 will also have its direction of movement changed to follow the region on the upper end 46a side of the rib 46, and then collide with the meshing portion E1 between the first gear 521 and the transmission gear 511 from below, lubricating the area around the meshing portion E1.
[0052] In the modified example, the case in which the rib 46A is bent at the bent portion 46d is shown as an example. However, the shape of the rib 46A around the bent portion 46d may be formed as an arc with its apex pointing upwards, so that the oil OL moves along the arc-shaped region, thereby smoothly changing the direction of movement of the oil OL toward the meshing portion E1.
[0053] 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 the power of the motor M is input, 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, a rib 46 (raised rib) having height in the direction of axis X1 is provided below the first gear 521 when viewed from the axial direction of the input shaft 51 (axis X1 direction). When viewed from the axial direction of the input shaft 51, the lower end 46b of the rib 46 is located on the side of the output shaft axis (axis X3) that is closer to the axis of the intermediate shaft 52 (axis X2). The upper end 46a of the rib 46 is on the input shaft 51 side that is closer to the axis of the intermediate shaft 52 (axis X2), and is located above the lower end of the transmission gear 511.
[0054] According to this embodiment, a portion of the oil OL scooped up by the final gear F is drawn into the first gear 521, which rotates in the opposite direction to the rotation of the final gear F, and moves downward from the axis X3 side (left side in Figure 3) of the first gear 521. A rib 46 (scooping rib) is provided below the first gear 521. The rib 46 crosses a vertical line VL2 passing through the axis X2 from the axis X3 side to the axis X1 side, and the height of the rib 46 in the Z direction increases as it moves from the axis X3 side to the axis X1 side. Here, the oil OL drawn into the first gear 521 moves diagonally downward from the axis X3 side as seen from the first gear 521 towards the axis X1 side. As the rib 46 is positioned to cross the direction of movement of the oil OL, the oil OL moving diagonally downward collides with the rib 46. Of the oil OL that collides with the rib 46, the oil OL that collides with the upper end 46a of the rib 46 has its direction of movement changed from diagonally downward on the axis X1 side to diagonally upward. As a result, it moves toward the meshing portion E1 between the transmission gear 511 and the first gear 521, which is located diagonally upward when viewed from the upper end 46a, and lubricates the area around the meshing portion E1 from below.
[0055] For example, a catch tank could be provided diagonally to the upper right of the meshing portion E1 in the gear chamber S2 to capture the oil OL scraped up by the final gear F, so that the oil OL overflowing from the catch tank drips onto the meshing portion E1 from above. However, in this case, the dripped oil OL may be repelled by the rotating gears (transmission gear 511, first gear 521), and if the meshing portion E1 is lubricated solely by the dripping oil OL, the lubrication of the meshing portion E1 may be insufficient. In contrast, as in the embodiment, by adopting a configuration in which the oil OL whose direction of movement is changed by the rib 46 lubricates the area around the meshing portion E1 from below, the oil OL can be efficiently supplied to the meshing portion E1. In particular, since the lower side of the meshing portion E1 is the starting side of the meshing between the transmission gear 511 and the first gear 521, the oil OL directed from below towards the meshing portion E1 is less likely to be repelled by the rotating gears (transmission gear 511, first gear 521). This allows the meshing portion E1 to be properly lubricated. The essence of the present invention lies in the configuration in which the rib 46 guides the oil OL towards the first gear 521 side. In particular, when the final gear F scoops up little oil OL, such as when a vehicle equipped with the drive unit 1 is traveling at a low speed, more oil OL can be reliably supplied around the meshing portion E1 to lubricate it, compared to when the meshing portion E1 is lubricated with oil OL dripping from the catch tank. Furthermore, by lubricating the meshing portion E1 from below, the continuity of lubrication is improved, which helps to suppress initial wear and alleviate lubrication deficiencies during low-speed driving.
[0056] (2) When viewed from the axial direction of the input shaft 51 (axis X1 direction), the upper end 46a of the rib 46 is located below the normal L2 which is perpendicular to the straight line L1 that passes through the meshing portion E1 between the transmission gear 511 and the first gear 521 and connects the axis of the input shaft 51 (axis X1) and the axis of the intermediate shaft 52 (axis X2).
[0057] According to this embodiment, the area around the meshing portion E1 between the transmission gear 511 and the first gear 521 can be properly lubricated. Here, if the upper end 46a of the rib 46 is located above the normal L2, the amount of oil OL supplied to the first gear 521, which is located above the normal L2, increases. Furthermore, as the upper end 46a of the rib 46 approaches the first gear 521, the oil OL that collides with the upper end 46a of the rib 46 collides with the first gear 521 at an angle to the outer circumference of the first gear 521. In this case, the amount of oil OL that reaches the meshing portion E1 between the transmission gear 511 and the first gear 521 may decrease. With the above configuration, it is possible to secure an amount of oil OL that reaches the area around the meshing portion E1 between the transmission gear 511 and the first gear 521 that is greater than the amount of oil OL that reaches the outer circumference of the first gear 521, so that the meshing portion E1 can be lubricated more appropriately.
[0058] (3) When viewed from the axial direction (axis X1 direction) of the input shaft 51, an extension portion 462 is provided on the upper end 46a side of the rib 46A, extending in a direction toward the meshing portion E1 between the transmission gear 511 and the first gear 521 along the normal L2.
[0059] According to this embodiment, an extension 462 is provided on the upper end 46a side of the rib 46A, extending in a direction toward the meshing portion E1 along the normal L2. This allows the direction of movement of the oil OL that collides with the bent portion 46d of the rib 46A to be changed to a direction toward the extension 462. As a result, much of the oil OL flowing along the extension 462 collides with the meshing portion E1 between the first gear 521 and the transmission gear 511 from below. This allows the area around the meshing portion E1 to be lubricated.
[0060] (4) When viewed from the axial direction (axis X1 direction) of the input shaft 51, the lower end 46b of the rib 46 is below the lower end of the final gear F and faces the region 42A of the circumferential wall 42 which is the bottom wall of the gear chamber S2, with a gap CL between them.
[0061] Oil OL for lubricating the power transmission mechanism 5 is stored in the lower part of the gear chamber S2. When the vehicle equipped with the drive unit 1 is running, the oil OL stored in the lower part of the gear chamber S2 is scooped up by the final gear F and supplied to the input shaft 51 side, passing over the intermediate shaft 52 side. The oil OL supplied to the input shaft 51 side then falls back down to the lower part of the gear chamber S2 and is scooped up again by the final gear F. If the amount of oil OL remaining in the lower part of the gear chamber S2 becomes large, the oil OL will act as resistance to the rotation of the differential mechanism 6 (differential case DEF, final gear F), which may affect the efficiency of transmitting the power (rotational driving force) of the motor M to the drive wheels WH, WH. By providing a rib 46 and setting a gap CL between the lower end 46b of the rib 46 and the peripheral wall portion 42 (region 42A), the amount of oil OL returning from the region below the input shaft 51 in the gear chamber S2 to the region where the differential mechanism 6 is installed in the gear chamber S2 can be adjusted. This reduces the resistance when the final gear F scoops up the oil OL.
[0062] (I) When viewed from the axial direction (axis X1 direction) of the input shaft 51, an arc-shaped region 461 is provided between the upper end 46a and the lower end 46b of the rib 46, which forms an arc along the outer circumference of the final gear F (output shaft gear).
[0063] With this configuration, when a vehicle equipped with the drive unit 1 is running, the amount of oil OL in the region of the gear chamber S2 where the differential mechanism 6 is provided can be suppressed, thereby reducing the resistance when the final gear F scoops up the oil OL.
[0064] (II) When viewed from the axial direction (axis X1 direction) of the input shaft 51, a bent portion 46c is provided on the lower end 46b side of the rib 46. The portion below the bent portion 46c on the lower end 46b side extends linearly away from the outer circumference of the final gear F.
[0065] The gap CL between the lower end 46b of the rib 46 and the peripheral wall portion 42 (region 42A) can be made narrower than the gap between the final gear F and the peripheral wall portion 42 (region 42A). Therefore, when a vehicle equipped with the drive unit 1 is running, the amount of oil OL in the region where the differential mechanism 6 is provided in the gear chamber S2 can be suppressed, thereby reducing the resistance when the final gear F scrapes up the oil OL.
[0066] (5) Viewed from the axial direction of the input shaft 51 (axis X1 direction), the side wall portion 41 of the housing portion (gear chamber S2) of the power transmission mechanism 5 is provided with a recess 48 below the first gear 521, which is recessed in a direction away from the final gear F in the axis X1 direction. Viewed from the axis X1 direction, an opening 47 is provided at the bottom of the recess 48, which connects the inside and outside of the gear chamber S2 and penetrates in the axis X1 direction. Viewed from the axis X1 direction, the recess 48 has a third curved portion 453 (arc-shaped wall portion) that surrounds the opening 47. Viewed from the axis X1 direction, the third curved portion 453 bypasses below the opening 47 and extends from the output shaft (axis X3) side to the input shaft 51 (axis X1) side, and is inscribed (connected) to the rib 46 beyond the axis (axis X2) of the intermediate shaft 52.
[0067] When the vehicle equipped with the drive unit 1 is in motion, the rotating first gear 521 causes oil OL to flow into the recess 48. A portion of the oil OL that flows into the recess 48 moves circumferentially along the arc-shaped third curved section 453. Here, the third curved section 453 is inscribed within the rib 46, and the region on the upper end 46a side of the rib 46 is circumscribed with the third curved section 453. Therefore, the oil OL that has moved circumferentially along the third curved section 453 merges with the flow of oil OL that has collided with the rib 46 at the upper end 46a of the rib 46 and is supplied around the meshing portion E1 between the transmission gear 511 and the first gear 521. This increases the amount of oil OL supplied around the meshing portion E1, allowing for proper lubrication of the area around the meshing portion E1. In other words, the supply of oil OL from the recess 48 merges with the flow of oil OL that has collided with the rib 46, thereby increasing the amount of oil OL supplied to the meshing portion E1. Furthermore, even if the first gear 521 creates a downward flow of oil OL, the arc-shaped side surface (third curved section 453) of the recess 48 located below the first gear 521 changes the direction of movement of the oil OL from downward to upward toward the first gear 521. As a result, much of the oil OL that has moved along the third curved section 453 is supplied around the meshing portion E1 between the transmission gear 511 and the first gear 521. This increases the amount of oil OL supplied around the meshing portion E1, allowing the meshing portion E1 to be properly lubricated.
[0068] (6) Viewed from the axial direction (axis X1 direction) of the input shaft 51, the side wall portion 41 of the gear chamber S2 (housing portion of the power transmission mechanism 5) is provided with a first region 43 covering the sides of the first gear 521 and the transmission gear 511, and a second region 44 covering the lower side of the final gear F, both positioned offset in the axis X1 direction. The boundary between the first region 43 and the second region 44 is formed by a first circumferential wall portion 431 surrounding the outer circumference of the first gear 521, a second circumferential wall portion 432 extending in the tangential direction (straight line L4 direction) of the first gear 521, and a third circumferential wall portion 433 surrounding the opening 47 at predetermined intervals, all connected in series. The third circumferential wall portion 433 bypasses the lower part of the opening 47 and extends from the axis X3 side to the axis X2 side, and beyond the vertical line VL2 it is inscribed (connected) to the rib 46.
[0069] According to this embodiment, the oil OL, which is drawn into the rotating first gear 521 and moves downward between the first circumferential wall portion 431 and the first gear 521, passes through the second circumferential wall portion 432 and reaches the region of the third circumferential wall portion 433. As a result, it flows along the third circumferential wall portion 433, changing its direction of movement to align with the region on the upper end 46a side of the rib 46. This allows much of the oil OL flowing along the third circumferential wall portion 433 to collide with the meshing portion E1 between the first gear 521 and the transmission gear 511 from below, thereby lubricating the meshing portion E1.
[0070] (III) In the first region 43, a bulge 45 is provided that bulges out from the second circumferential wall 432 toward the first gear 521. The height h45 of the bulge 45 in the direction of axis X1 is smaller than the offset amount (h43) between the first region 43 and the second region 44 in the direction of axis X1. The bulge 45 has a shape in which a first curved section 451, a second curved section 452, and a third curved section 453 are connected in series. When viewed from the direction of axis X1, the first curved section 451 is in the shape of an arc along a virtual circle Im2 along the inner circumference of the first circumferential wall 431. The first curved section 451 extends in the direction toward the vertical line VL2 from the intersection point Pa of the diameter line L51a and the first circumferential wall 431. The first curved section 451 is connected to the second curved section 452 at the intersection point Pb of the other diameter line L51b of the first gear 521 and the virtual circle Im2. The upper end 46a side of the rib 46 is provided crossing in the Z direction of a straight line L3 that extends tangentially to the virtual circle Im2 passing through the intersection point Pb.
[0071] With this configuration, the oil OL moving along the first curved section 451, upon reaching the second curved section 452, spreads downward due to centrifugal force and moves along the straight line L3, colliding with the area on the upper end 46a side of the rib 46. As a result, the direction of movement of the oil OL is changed to a direction toward the meshing section E1, and the meshing section E1 between the first gear 521 and the transmission gear 511 is lubricated by the oil colliding from below. This ensures that the area around the meshing section E1 is properly lubricated.
[0072] (IV) When viewed from the direction of axis X1, the recess 48 communicates with the lower part of the first region 43. The recess 48 protrudes downward from a virtual circle Im2 that extends along the extension of the first peripheral wall portion 431. The third curved portion 453 bypasses the lower part of the opening 47 and extends from the axis X3 side to the axis X2 side, and beyond the vertical line VL2 it is inscribed in the rib 46.
[0073] With this configuration, a portion of the oil OL flowing through the first curved section 451 of the bulging section 45 moves along the second curved section 452 and flows into the recess 48. The oil OL that has flowed into the recess 48 flows along the third curved section 453, changing its direction of movement to align with the region on the upper end 46a side of the rib 46. As a result, the oil OL that has flowed into the recess 48 also collides with the meshing section E1 between the first gear 521 and the transmission gear 511 from below, lubricating the meshing section E1.
[0074] In the embodiment described above, as shown in Figure 2, an example was given in which the rib 46 has a bent portion 46c between its upper end 46a and lower end 46b. In this rib 46, the section between the upper end 46a and the bent portion 46c forms an arc shape surrounding the outer circumference of the final gear F, while the section from the bent portion 46c to the lower end 46b forms a straight line extending away from the outer circumference of the final gear F. Therefore, the upper end 46a of the rib 46 has the role of changing the direction of movement of the oil OL drawn into the first gear 521 toward the meshing portion E1 between the transmission gear 511 and the first gear 521. The lower end 46b of the rib 46 has the role of adjusting the amount of movement of the oil OL toward the rotating final gear F.
[0075] Here, the shape of the rib 46 is not limited to the shape shown in Figure 2. At a minimum, the rib 46 only needs to have a shape that can change the direction of movement of the oil OL drawn into the first gear 521 toward the meshing portion E1 between the transmission gear 511 and the first gear 521. Therefore, for example, when viewed from the axial direction of the input shaft 51 (axis X1 direction), the arc-shaped region 461 of the rib 46 may be defined as a range from the upper end 46a to the position where it intersects with the diameter line Lf of the final gear F, and its shape may only serve the function of changing the direction of movement of the oil OL drawn into the first gear 521 toward the meshing portion E1.
[0076] Although embodiments of the present invention have been described above, these embodiments are merely examples of how the present invention can be applied, and the technical scope of the present invention is not intended to be limited to the specific configurations of the above embodiments. Modifications can be made as appropriate within the scope of the technical concept of the invention. That is, each element shown in the figures can be arbitrarily changed, and the present invention is not limited to these. For example, similar effects can be achieved by using other scraping members instead of ribs.
[0077] 1: Drive unit, 5: Power transmission mechanism, 41: Side wall, 42: Peripheral wall, 42A: Area that becomes the bottom wall, 43: First area, 431: First peripheral wall, 432: Second peripheral wall, 433: Third peripheral wall, 44: Second area, 453: Third curved section (arc-shaped wall), 46: Rib (raised rib), 46a: Upper end, 46b: Lower end, 462: Extension, 47: Opening, 48: Recess, 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), DS: Drive shaft (output shaft), E1: Meshing section, F: Final gear (output shaft gear), HS: Housing (case), L1: Straight line, L2: Normal line, M: Motor, S2: Gearbox (householding for power transmission mechanism), WH: Drive wheel, X1: Axle (center of input shaft), X2: Axle (center of intermediate shaft), X3: Axle (center 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 the power input to the input shaft is transmitted; an output shaft to which the 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, viewed from the axial direction of the input shaft, the housing portion has a scraping rib below the first intermediate shaft gear having a height in the axial direction of the input shaft. A drive device in which, when viewed from the axial direction of the input shaft, the lower end of the scraping rib is located on the output shaft side of the axis of the intermediate shaft, and the upper end of the scraping rib is located on the input shaft side of the axis of the intermediate shaft and above the lower end of the input shaft gear.
2. The drive device according to claim 1, wherein, viewed from the axial direction of the input shaft, the upper end of the scraping rib is located below a normal that passes through the meshing portion of the input shaft gear and the first intermediate shaft gear and is perpendicular to the straight line connecting the axis of the input shaft and the axis of the intermediate shaft.
3. The drive device according to claim 2, wherein, when viewed from the axial direction of the input shaft, an extension is provided on the upper end side of the scraping rib that extends in a direction toward approaching the meshing portion between the input shaft gear and the first intermediate shaft gear along the normal.
4. The drive device according to claim 2, wherein, viewed from the axial direction of the input shaft, the lower end of the scraping rib is below the lower end of the output shaft gear and faces the bottom wall of the housing with a gap between them.
5. The drive device according to any one of claims 1 to 4, wherein, as viewed from the axial direction of the input shaft, the side wall of the housing portion has a recess below the first intermediate shaft gear, which is recessed in a direction away from the output shaft gear in the axial direction of the input shaft; as viewed from the axial direction of the input shaft, an opening is provided at the bottom of the recess that connects the inside and outside of the housing portion, which penetrates in the axial direction of the input shaft; as viewed from the axial direction of the input shaft, the recess has an arc-shaped wall portion that surrounds the opening; the arc-shaped wall portion bypasses below the opening, extends from the output shaft side to the input shaft side, and connects to the scraping rib beyond the axis of the intermediate shaft.
6. The drive device according to claim 5, wherein, as viewed from the axial direction of the input shaft, the side wall portion of the housing portion is provided with a first region covering the side of the first intermediate shaft gear and a second region covering the side of the output shaft gear, offset in position in the axial direction of the input shaft, the boundary between the first region and the second region is formed by a first circumferential wall portion surrounding the outer circumference of the first intermediate shaft gear, a second circumferential wall portion extending in the tangential direction of the first intermediate shaft gear, and a third circumferential wall portion surrounding the opening at predetermined intervals, all connected in series, the third circumferential wall portion bypasses below the opening and extends from the output shaft side to the input shaft side, and connects to the scraping rib beyond the axis of the intermediate shaft.