Gear device and drive device

Abstract

To provide a gear device having a structure capable of suppressing fluid from being stagnant inside a penetration part, and a drive device.SOLUTION: One aspect of a gear device of the present invention includes: a plurality of gears that rotate about a rotational axial line extending in a first direction perpendicular to a vertical direction; and a gear housing that stores the plurality of gears therein. The gear housing has a first penetration part communicating an inside of the gear housing and an outside of the gear housing. The first penetration part has an inner opening that is opened to the inside of the gear housing, and an outer opening that is opened to the outside of the gear housing. The outer opening is closed by a first plug member. The entire outer opening is provided at a position different from the plurality of gears in the first direction.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Conventionally, a drive device in which lubricating oil is stored in a gear chamber is known (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the drive device as described above, for example, when injecting lubricating oil into the gear chamber, a through-hole connecting the inside and the outside of the gear chamber may be provided in the gear case provided with the gear chamber. In this case, a part of the lubricating oil, which is a fluid scattered in the gear chamber by being lifted by the gear or the like, may accumulate in the through-hole, and there is a risk that the lubricating oil supplied to the gear and the bearing may be insufficient.

[0005] In view of the above circumstances, one object of the present invention is to provide a gear device and a drive device having a structure capable of suppressing the accumulation of fluid in the through-hole.

Means for Solving the Problems

[0006] One aspect of the gear device of the present invention includes a plurality of gears that rotate around a rotation axis extending in a first direction orthogonal to the vertical direction, and a gear housing that houses the plurality of gears therein. The gear housing has a first through-hole that connects the inside of the gear housing and the outside of the gear housing. The first through-hole has an inner opening that opens to the inside of the gear housing and an outer opening that opens to the outside of the gear housing. The outer opening is closed by a first plug member. The entire outer opening is provided at a position different from the plurality of gears in the first direction.

[0007] One aspect of the drive device of the present invention includes the above gear device and a motor connected to the gear device.

Advantages of the Invention

[0008] According to one aspect of the present invention, in the gear device and the drive device, it is possible to suppress the accumulation of fluid in the through-hole.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0010] In the drawings, an XYZ coordinate system is shown as a three-dimensional orthogonal coordinate system as appropriate. In the XYZ coordinate system, the Z-axis direction is the vertical direction. The side to which the arrow of the Z-axis points (+Z side) is the upper side, and the side opposite to the side to which the arrow of the Z-axis points (-Z side) is the lower side. The X-axis direction is a direction orthogonal to the Z-axis direction and is the front-rear direction of the vehicle on which the drive device in the following embodiments is mounted. In the following embodiments, the side to which the arrow of the X-axis points (+X side) is the front side of the vehicle, and the side opposite to the side to which the arrow of the X-axis points (-X side) is the rear side of the vehicle. The Y-axis direction is a direction orthogonal to both the X-axis direction and the Z-axis direction and is the left-right direction of the vehicle, that is, the vehicle width direction. In the following embodiments, the side to which the arrow of the Y-axis points (+Y side) is the left side of the vehicle, and the side opposite to the side to which the arrow of the Y-axis points (-Y side) is the right side of the vehicle.

[0011] Note that the positional relationship in the front-rear direction is not limited to the positional relationship in the following embodiments, and the +X side may be the rear side of the vehicle and the -X side may be the front side of the vehicle. In this case, the +Y side is the right side of the vehicle, and the -Y side is the left side of the vehicle. Also, in this specification, the "parallel direction" includes a substantially parallel direction, and the "orthogonal direction" includes a substantially orthogonal direction.

[0012] The central axis J1 shown appropriately in the figure is a virtual axis extending in a direction intersecting the vertical direction. More specifically, the central axis J1 extends in the Y-axis direction orthogonal to the vertical direction, that is, in the left-right direction of the vehicle. In the following description, unless otherwise specified, the direction parallel to the central axis J1 is simply referred to as the "axial direction", the radial direction centered on the central axis J1 is simply referred to as the "radial direction", and the circumferential direction centered on the central axis J1 is simply referred to as the "circumferential direction". In the following description, the left side (+Y side) in the axial direction is referred to as the "one side in the axial direction", and the right side (-Y side) in the axial direction is referred to as the "other side in the axial direction". The vertical direction is, for example, the vertical direction, and the front-rear direction and the left-right direction (axial direction) are, for example, the horizontal directions orthogonal to the vertical direction. In the following embodiments, the left-right direction (axial direction, Y-axis direction) corresponds to the "first direction" orthogonal to the vertical direction, and the front-rear direction (X-axis direction) corresponds to the "second direction" orthogonal to both the first direction and the vertical direction. The one side in the axial direction (+Y side) is, for example, the one side in the first direction. The other side in the axial direction (-Y side) is, for example, the other side in the first direction. The front side (+X side) is, for example, the one side in the second direction. The rear side (-X side) is, for example, the other side in the second direction.

[0013] <First Embodiment> The drive device 100 of the present embodiment shown in FIG. 1 is a drive device mounted on a vehicle and rotates an axle. The vehicle on which the drive device 100 is mounted is a vehicle using a motor as a power source, such as a hybrid electric vehicle (HEV), a plug-in hybrid vehicle (PHV), or an electric vehicle (EV). As shown in FIG. 1, the drive device 100 includes a motor 10, a gear device 20, and a control device 60.

[0014] The motor 10 is connected to the gear device 20. As shown in FIG. 2, the motor 10 includes a rotor 11 rotatable about the central axis J1, a stator 12 facing the rotor 11 with a gap therebetween, and a motor housing 31. The gear device 20 includes a gear mechanism 20a and a gear housing 32. The gear device 20 transmits the rotation of the rotor 11, which will be described later in the motor 10, to the axle of the vehicle.

[0015] The rotor 11 has a motor shaft 13 arranged along the central axis J1 and a rotor core 14 fixed to the outer peripheral surface of the motor shaft 13. The motor shaft 13 is rotatable about the central axis J1. The motor shaft 13 extends in the axial direction. The stator 12 is located radially outside the rotor 11. The stator 12 is annular and surrounds the rotor 11. The stator 12 has a stator core 15 and a plurality of coils 16.

[0016] The gear mechanism 20a is connected to the rotor 11. More specifically, the gear mechanism 20a is connected to the end of the motor shaft 13 on one axial side (+Y side). The gear mechanism 20a transmits the rotation of the rotor 11 to the vehicle axle. The gear mechanism 20a has a reduction device 21 connected to the rotor 11 and a differential device 22 connected to the reduction device 21. That is, the gear device 20 includes the reduction device 21 and the differential device 22.

[0017] The reduction gear 21 is connected to one axial end (+Y side) of the motor shaft 13. The reduction gear 21 has a first gear shaft 23a and a second gear shaft 23b extending in the axial direction, a first gear 24a, a second gear 24b, and a third gear 24c. The first gear shaft 23a is rotatably supported about the central axis J1 by a pair of bearings 25a and 25b provided in the gear device 20. The first gear shaft 23a is connected to one axial end of the motor shaft 13. The second gear shaft 23b is rotatable about an intermediate axis J2 extending in the axial direction. In the present embodiment, the intermediate axis J2 is a virtual axis extending parallel to the central axis J1. As shown in FIG. 3, the intermediate axis J2 is located, for example, above the central axis J1 and behind the central axis J1 (-X side). As shown in FIG. 2, the second gear shaft 23b is rotatably supported about the intermediate axis J2 by a pair of bearings 25c and 25d provided in the gear device 20. The bearings 25a, 25b, 25c, and 25d are rolling bearings such as ball bearings, for example. The bearings 25a and 25b are bearings that rotatably support the first gear 24a. The bearings 25c and 25d are bearings that rotatably support the second gear 24b and the third gear 24c.

[0018] The first gear 24a is a gear provided on the first gear shaft 23a. The first gear 24a is provided on the outer peripheral surface of the first gear shaft 23a. In the present embodiment, the rotation axis of the first gear 24a is the central axis J1. The second gear 24b and the third gear 24c are gears provided on the second gear shaft 23b. The second gear 24b and the third gear 24c are provided on the outer peripheral surface of the second gear shaft 23b. In the present embodiment, the rotation axis of the second gear 24b and the rotation axis of the third gear 24c are the intermediate axis J2. That is, the third gear 24c is a gear that rotates around the same rotation axis as the second gear 24b. The second gear 24b meshes with the first gear 24a. As shown in FIG. 3, the outer diameter of the second gear 24b is larger than the outer diameter of the third gear 24c. The outer diameter of the first gear 24a is smaller than the outer diameter of the third gear 24c. As shown in FIG. 4, the first gear 24a and the second gear 24b are located on the other axial side (-Y side) than the third gear 24c. Among the plurality of gears (the first to third gears 24a, 24b, 24c) of the gear mechanism 20a, if one gear located relatively lower is defined as the "lower gear" and the other gear whose rotation axis is located above the "lower gear" is defined as the "upper gear", in the present embodiment, the first gear 24a can be rephrased as the "lower gear", and the second gear 24b and the third gear 24c can be rephrased as the "upper gear".

[0019] The differential device 22 has a ring gear 22a that is rotatable about a differential axis J3 extending in the axial direction. In the present embodiment, the differential axis J3 is an imaginary axis extending parallel to the central axis J1. As shown in FIG. 3, in the present embodiment, the differential axis J3 is located at substantially the same position as the central axis J1 in the vertical direction. More specifically, the differential axis J3 is located above the central axis J1. In the present embodiment, the differential axis J3 is located below the intermediate axis J2. The differential axis J3 is provided at a position different from the central axis J1 in the front-rear direction (X-axis direction). In the present embodiment, the differential axis J3 is located on the rear side (-X side) of the central axis J1 and the intermediate axis J2. The ring gear 22a is a fourth gear that meshes with the third gear 24c. As shown in FIG. 2, the lower end of the ring gear 22a is immersed in the oil 90 stored in a first storage portion 32d, which will be described later, provided in the gear housing 32. When the ring gear 22a rotates, the oil 90 is stirred up. The stirred-up oil 90 is supplied as lubricating oil to, for example, each gear provided in the gear mechanism 20a and each bearing that rotatably supports each gear.

[0020] In the present embodiment, the first gear 24a, the second gear 24b, the third gear 24c, and the ring gear 22a are gears that rotate about a rotation axis extending in the axial direction orthogonal to the vertical direction. That is, in the present embodiment, the gear device 20 includes four gears, namely, the first gear 24a, the second gear 24b, the third gear 24c, and the ring gear 22a, as gears that rotate about a rotation axis extending in the axial direction orthogonal to the vertical direction. In the following description, when the first gear 24a, the second gear 24b, the third gear 24c, and the ring gear 22a are not particularly distinguished, these gears are collectively referred to simply as "gears".

[0021] A pair of output shafts 29 are connected to the differential device 22. The pair of output shafts 29 extend in the axial direction. The pair of output shafts 29 are axles to which wheels of a vehicle (not shown) are respectively connected. The torque output from the motor 10 is transmitted to the wheels of the vehicle via the speed reduction device 21 and the differential device 22.

[0022] The motor housing 31 and the gear housing 32 are arranged side by side in the axial direction. The motor housing 31 houses the rotor 11 and the stator 12 therein. The gear housing 32 houses the gear mechanism 20a, that is, the speed reducer 21 and the differential device 22 therein. That is, the gear housing 32 houses a plurality of gears including the first gear 24a, the second gear 24b, the third gear 24c, and the ring gear 22a therein. The gear housing 32 is located on one axial side (+Y side) of the motor housing 31. The gear housing 32 is connected to the motor housing 31. In the present embodiment, the motor housing 31 and the gear housing 32 constitute the housing 30 provided in the drive device 100. As shown in FIG. 1, the gear housing 32 protrudes to the rear side (-X side) of the motor housing 31.

[0023] As shown in FIG. 2, in the present embodiment, the housing 30 has a housing main body 30a, a motor cover 30b, and a gear cover 30c. In the present embodiment, the housing main body 30a, the motor cover 30b, and the gear cover 30c are each made of metal. Note that the materials constituting the housing main body 30a, the motor cover 30b, and the gear cover 30c are not particularly limited, and may be materials other than metal such as resin. The housing main body 30a, the motor cover 30b, and the gear cover 30c are separate from each other. The housing main body 30a has a first peripheral wall portion 30d, a second peripheral wall portion 30e, and a partition wall portion 30h. As shown in FIG. 4, the housing main body 30a has a side wall portion 32f. In the present embodiment, the motor housing 31 is constituted by the partition wall portion 30h, the first peripheral wall portion 30d, and the motor cover 30b. In the present embodiment, the gear housing 32 is constituted by the partition wall portion 30h, the second peripheral wall portion 30e, the gear cover 30c, and the side wall portion 32f.

[0024] The first peripheral wall portion 30d is a peripheral wall portion that surrounds the stator 12 from the radially outer side. The first peripheral wall portion 30d is cylindrical and opens to the other axial side (-Y side). A partition wall portion 30h is provided at the end of the first peripheral wall portion 30d on one axial side (+Y side). The opening on the other axial side of the first peripheral wall portion 30d is closed by a motor cover 30b fixed to the end of the first peripheral wall portion 30d on the other axial side.

[0025] The second peripheral wall portion 30e of the housing main body 30a is cylindrical and opens to one axial side (+Y side). A partition wall portion 30h and a side wall portion 32f are provided at the end of the second peripheral wall portion 30e on the other axial side (-Y side). The opening on one axial side of the second peripheral wall portion 30e is closed by a gear cover 30c fixed to the end of the second peripheral wall portion 30e on one axial side.

[0026] As shown in FIG. 2, the partition wall portion 30h separates the inside of the motor housing 31 from the inside of the gear housing 32. The partition wall portion 30h is a wall portion that axially separates the inside of the motor housing 31 from the inside of the gear housing 32. Bearings 25b and 25d are held by the partition wall portion 30h. As shown in FIG. 4, the side wall portion 32f extends rearward (-X side) from the partition wall portion 30h. The side wall portion 32f constitutes the wall portion on the other axial side (-Y side) of the portion of the gear housing 32 that protrudes rearward from the motor housing 31. The partition wall portion 30h and the side wall portion 32f constitute the wall portion on the other axial side of the gear housing 32.

[0027] The gear cover 30c has a lid wall portion 32a that covers the gear mechanism 20a from one axial side, and a third peripheral wall portion 30g that projects from the radially outer edge portion of the lid wall portion 32a to the other axial side. As shown in FIG. 1, in the present embodiment, the lid wall portion 32a has a substantially elliptical shape that is long in the front-rear direction (X-axis direction). The lid wall portion 32a is a wall portion on one axial side (+Y side) of the gear housing 32. As shown in FIG. 2, the lid wall portion 32a is provided with a bearing holding portion 35a for holding the bearing 25a and a bearing holding portion 35c for holding the bearing 25c. The bearing holding portion 35a is annular and surrounds the central axis J1. The bearing holding portion 35c is annular and surrounds the intermediate axis J2.

[0028] As shown in FIG. 3, the lid wall portion 32a is provided with a bearing holding portion 35e for holding a bearing 25e that rotatably supports the ring gear 22a. The bearing 25e is a rolling bearing such as a ball bearing, for example. The bearing holding portion 35e is cylindrical and surrounds the differential axis J3. As shown in FIG. 1, the lid wall portion 32a is provided with a through hole 36 that penetrates the lid wall portion 32a in the axial direction. The through hole 36 is circular with the differential axis J3 as the center when viewed in the axial direction. The output shaft 29 is passed through the through hole 36. Here, as described above, the lid wall portion 32a is a part of the gear housing 32 and has the bearing holding portions 35a, 35c, and 35e. That is, the gear housing 32 has bearing holding portions 35a, 35e, and 35c for holding the bearings 25a, 35e, and 25c that rotatably support a plurality of gears.

[0029] As shown in FIG. 2, the end portion on the other axial side (-Y side) of the third peripheral wall portion 30g is connected to the end portion on one axial side (+Y side) of the second peripheral wall portion 30e. The second peripheral wall portion 30e and the third peripheral wall portion 30g constitute a gear peripheral wall portion 32b that surrounds the gear mechanism 20a from the radially outer side. As shown in FIG. 1, in the present embodiment, the gear peripheral wall portion 32b has a substantially elliptical cylindrical shape that surrounds the central axis J1, the intermediate axis J2, and the differential axis J3.

[0030] As shown in FIG. 2, in the present embodiment, the housing 30 has a first storage portion 32d in which oil 90 as a fluid is stored. The oil 90 is used as lubricating oil for each gear provided in the gear mechanism 20a and each bearing that rotatably supports each gear. As the oil 90, for example, in order to function as lubricating oil, it is preferable to use an oil equivalent to an automatic transmission fluid (ATF) having a relatively low viscosity. Note that the oil 90 may be used as a refrigerant for cooling the motor 10. The first storage portion 32d is constituted by a lower portion of the gear housing 32. The inside of the first storage portion 32d is constituted by a lower region inside the gear housing 32.

[0031] Note that the "inside of the gear housing 32" is, for example, an internal space surrounded by the surface on the other axial side (-Y side) of the lid wall portion 32a, the inner peripheral surface of the gear peripheral wall portion 32b, the surface on one axial side (+Y side) of the partition wall portion 30h, and the surface on one axial side of the side wall portion 32f.

[0032] As shown in FIG. 1, the gear housing 32 has a convex portion 33 that protrudes axially on one side (+Y side) from the surface on one axial side of the lid wall portion 32a. In the present embodiment, the convex portion 33 is provided at the upper end portion of the surface on one axial side of the lid wall portion 32a. The convex portion 33 is located above the central axis J1, the intermediate axis J2, and the differential axis J3. As shown in FIG. 3, in the present embodiment, the convex portion 33 is located on the rear side (-X side) of the intermediate axis J2 and on the front side (+X side) of the differential axis J3.

[0033] As shown in FIGS. 5 and 6, the convex portion 33 has a first portion 33a and a second portion 33b. The first portion 33a is substantially rectangular parallelepiped-shaped. In the present embodiment, the upper surface of the first portion 33a is provided at the same position in the vertical direction as the upper surface of the gear peripheral wall portion 32b. The upper surface of the first portion 33a is connected to the upper surface of the gear peripheral wall portion 32b. The second portion 33b is located below the first portion 33a. The second portion 33b is connected to the lower end portion of the first portion 33a. The second portion 33b is substantially triangular when viewed in the front-rear direction (X-axis direction). The axial dimension of the second portion 33b becomes smaller toward the lower side.

[0034] The gear housing 32 has a first through portion 51 that connects the inside of the gear housing 32 and the outside of the gear housing 32. The first through portion 51 has an inner opening portion 51d that opens to the inside of the gear housing 32 and an outer opening portion 51c that opens to the outside of the gear housing 32. In the present embodiment, the first through portion 51 is used as an oil injection hole for injecting oil 90 into the gear housing 32. In the present embodiment, the first through portion 51 is provided in the convex portion 33. The first through portion 51 penetrates the convex portion 33. As shown in FIG. 3, the first through portion 51 is located on the rear side (-X side) of the intermediate axis J2 and on the front side (+X side) of the differential axis J3. The first through portion 51 is located above the central axis J1, the intermediate axis J2, and the differential axis J3.

[0035] As shown in FIGS. 5 and 6, the first through portion 51 has a hole portion 51a and a recess portion 51b. The hole portion 51a penetrates the first portion 33a in the vertical direction. In the present embodiment, the hole portion 51a is circular when viewed in the vertical direction. The upper end portion of the hole portion 51a is the outer opening portion 51c. In the present embodiment, the outer opening portion 51c is circular when viewed in the vertical direction.

[0036] The outer opening 51c is closed by the first plug member 41. The first plug member 41 is detachably attached to the outer opening 51c. Note that the first plug member 41 may be non-detachably attached to the outer opening 51c. In the present embodiment, the first plug member 41 is a screw member. More specifically, the first plug member 41 is a bolt. The first plug member 41 has a substantially cylindrical plug main body portion 41a extending in the vertical direction and a plug head portion 41b connected to the upper end portion of the plug main body portion 41a. As shown in FIG. 5, the plug main body portion 41a is screwed into the hole portion 51a from above. On the outer peripheral surface of the plug main body portion 41a, a first screw portion 41c that meshes with a second screw portion 51f provided on the inner peripheral surface of the hole portion 51a is provided. In the present embodiment, the lower end portion of the plug main body portion 41a is located above the lower end portion of the hole portion 51a. The plug head portion 41b is a substantially disc-shaped member that extends in a direction orthogonal to the vertical direction. The outer diameter of the plug head portion 41b is larger than the outer diameter of the plug main body portion 41a. The outer peripheral edge portion of the plug head portion 41b is located above the peripheral edge portion of the outer opening 51c on the upper surface of the convex portion 33. A seal member 44 is provided between the outer peripheral edge portion of the plug head portion 41b and the peripheral edge portion of the outer opening 51c on the upper surface of the convex portion 33 in the vertical direction. The seal member 44 contacts the outer peripheral edge portion of the plug head portion 41b and the peripheral edge portion of the outer opening 51c on the upper surface of the convex portion 33. In the present embodiment, the seal member 44 is an annular member that surrounds the plug main body portion 41a. The seal member 44 seals the space between the plug head portion 41b and the upper surface of the convex portion 33.

[0037] As shown in FIG. 4, the entire outer opening 51c is provided at a position different from a plurality of gears in the axial direction, that is, the first gear 24a, the second gear 24b, the third gear 24c, and the ring gear 22a. Therefore, at least a part of the first through portion 51 including the outer opening 51c can be arranged at a position axially displaced with respect to each gear. Thereby, the oil 90 scattered in the gear housing 32 due to the rotation of the gear can be made less likely to enter the first through portion 51, and the accumulation of the oil 90 in the first through portion 51 can be suppressed. Therefore, it is possible to suppress the shortage of the oil 90 supplied to each gear and each bearing accommodated in the gear housing 32. The oil 90 scattered in the gear housing 32 by the rotation of each gear includes the oil 90 lifted by the ring gear 22a. In the present embodiment, the entire outer opening 51c is located on one axial side (+Y side) with respect to the first gear 24a, the second gear 24b, the third gear 24c, and the ring gear 22a.

[0038] In the present embodiment, the outer opening 51c opens upward. Therefore, even if the oil 90 that has entered the first through portion 51 reaches the outer opening 51c or near the outer opening 51c, the oil 90 can be easily flowed downward by gravity. Thereby, the accumulation of the oil 90 in the first through portion 51 can be further suppressed. Further, even when a part of the vehicle body is disposed to face one axial side (+Y side) of the drive device 100 in a state where the drive device 100 is mounted on the vehicle, the first plug member 41 attached to the outer opening 51c can be easily removed from the upper side of the drive device 100. Further, as shown in FIG. 7, a pipe member 91 such as a hose for injecting the oil 90 into the gear housing 32 can be easily attached to the opened outer opening 51c from above. Thereby, in a state where the drive device 100 is mounted on the vehicle, an operator or the like can easily perform an operation of injecting the oil 90 into the gear housing 32.

[0039] In addition, in this specification, "worker, etc." includes the worker who performs each operation and devices, etc. Each operation may be performed only by the worker, only by the device, or by the worker and the device together.

[0040] As shown in FIG. 3, the outer opening 51c is located on the rear side (-X side) of the intermediate axis J2 and on the front side (+X side) of the differential axis J3. The outer opening 51c is located above the central axis J1, the intermediate axis J2, and the differential axis J3.

[0041] As shown in FIGS. 5 and 6, the recess 51b is provided in the second portion 33b. The recess 51b is recessed from the inner surface of the lid wall portion 32a, that is, the surface on the other axial side (-Y side) of the lid wall portion 32a toward the one axial side (+Y side). By providing the recess 51b, the second portion 33b is hollow. The lower end portion of the hole portion 51a opens at a portion on the one axial side of the surface located on the upper side among the inner surfaces of the recess 51b. Thereby, the inside of the hole portion 51a and the inside of the recess 51b are connected.

[0042] The recess 51b has an inner opening 51d that opens inside the gear housing 32. The inner opening 51d is the end portion on the other axial side (-Y side) of the recess 51b. In the present embodiment, the inner opening 51d opens in the axial direction. Therefore, it is possible to make it difficult for the oil 90 that scatters in the vertical direction when the gear rotates to enter the inner opening 51d. Thereby, it is possible to further suppress the accumulation of the oil 90 in the first through portion 51. In the present embodiment, the inner opening 51d opens on the other axial side. The inner opening 51d has a substantially rectangular shape that is long in the vertical direction when viewed in the axial direction. In the present embodiment, the opening area of the inner opening 51d is larger than the opening area of the outer opening 51c.

[0043] Of the inner surface of the recess 51b, the surface located on the lower side is an inclined surface 51e that is located on the lower side as it approaches the inner opening 51d. The surface located on the lower side of the inner surface of the recess 51b is the surface located on the lower side of the inner surface of the first through-hole 51. That is, the surface located on the lower side of the inner surface of the first through-hole 51 has the inclined surface 51e. Therefore, even if oil 90 enters the first through-hole 51, it is easy to flow the oil 90 along the inclined surface 51e toward the inner opening 51d. Thereby, it is easy to return the oil 90 that has entered the first through-hole 51 to the inside of the gear housing 32. Therefore, it is possible to further suppress the accumulation of the oil 90 in the first through-hole 51. Further, when an operator or the like injects the oil 90 into the gear housing 32 through the first through-hole 51, the oil 90 can be guided along the inclined surface 51e to the inner opening 51d as shown in FIG. 7. Therefore, it is possible to easily inject the oil 90 into the gear housing 32 through the first through-hole 51.

[0044] In the present embodiment, the inclined surface 51e is located on the lower side as it goes toward the other side in the axial direction (-Y side). The end on the other side in the axial direction of the inclined surface 51e is located at the inner opening 51d. In the present embodiment, the inclined surface 51e is a surface that extends linearly when viewed in the front-rear direction (X-axis direction). In the present embodiment, the inclined surface 51e constitutes the entire surface located on the lower side of the inner surface of the first through-hole 51.

[0045] In the present embodiment, the entire inner opening 51d is provided at a position different from that of a plurality of gears in the axial direction, that is, the first gear 24a, the second gear 24b, the third gear 24c, and the ring gear 22a. Therefore, it is easy to suppress the oil 90 scattered in the gear housing 32 from entering the inner opening 51d when the gears rotate. Thereby, it is possible to further suppress the accumulation of the oil 90 in the first through-hole 51. Therefore, it is possible to further suppress the shortage of the oil 90 supplied to each gear and each bearing housed in the gear housing 32. In the present embodiment, the entire inner opening 51d is located on one side in the axial direction (+Y side) with respect to the first gear 24a, the second gear 24b, the third gear 24c, and the ring gear 22a.

[0046] As shown in FIG. 3, the inner opening 51d and at least one gear have portions provided at the same position as each other in the front-rear direction (X-axis direction). Therefore, when an operator or the like injects oil 90 into the inside of the gear housing 32 through the first through-hole 51, the oil 90 flowing into the inside of the gear housing 32 from the inner opening 51d can be easily supplied to the at least one gear and the bearing that supports the at least one gear. Thereby, before the gear device 20 is first driven, the oil 90 can be easily supplied as lubricating oil to the at least one gear and the bearing.

[0047] In the present embodiment, the inner opening 51d and the second gear 24b have portions provided at the same position as each other in the front-rear direction (X-axis direction). The inner opening 51d and the third gear 24c have portions provided at the same position as each other in the front-rear direction. The inner opening 51d and the ring gear 22a have portions provided at the same position as each other in the front-rear direction. Therefore, when an operator or the like injects oil 90 into the inside of the gear housing 32 through the first through-hole 51, the oil 90 can be easily supplied to the second gear 24b, the third gear 24c, the ring gear 22a, and the respective bearings that support these gears.

[0048] When the intermediate axis J2 is located above the central axis J1 as in the present embodiment, the second gear 24b and the third gear 24c are located above compared to the case where the intermediate axis J2 is located at the same position as the central axis J1 in the vertical direction or below the central axis J1. Therefore, even when the gear device 20 is driven and the oil 90 in the first reservoir 32d is lifted by the ring gear 22a, it may be difficult to supply the oil 90 to the second gear 24b and the third gear 24c compared to the first gear 24a and the ring gear 22a. However, in the present embodiment, as described above, when an operator or the like injects the oil 90 into the inside of the gear housing 32 through the first through portion 51, the oil 90 can be easily supplied to the second gear 24b and the third gear 24c. Therefore, it is possible to easily supply the oil 90 to the second gear 24b and the third gear 24c before the gear device 20 is driven for the first time. For example, when the gear device 20 is driven for the first time, it is possible to suppress the shortage of the oil 90 in the second gear 24b and the third gear 24c. That is, the gear device 20 can be driven in a state where the oil 90 is previously supplied and lubricated to the second gear 24b and the third gear 24c.

[0049] The position in the front-rear direction (X-axis direction) of the entire inner opening 51d is included in the position in the front-rear direction of the second gear 24b. The entire inner opening 51d is provided at the same position as a part of the rear side (-X side) portion of the second gear 24b in the front-rear direction. A part of the front side (+X side) portion of the inner opening 51d is provided at the same position as the rear end of the third gear 24c in the front-rear direction. The entire inner opening 51d is provided within the range in the front-rear direction between one end and the other end of the ring gear 22a in the front-rear direction. The entire inner opening 51d is provided at the same position as the rear end of the ring gear 22a in the front-rear direction.

[0050] The inner opening 51d and the bearing 25c have portions provided at the same position as each other in the front-rear direction (X-axis direction). Therefore, when an operator or the like injects oil 90 into the inside of the gear housing 32 through the first through portion 51, the oil 90 flowing into the inside of the gear housing 32 from the inner opening 51d can be easily supplied to the bearing 25c. Thereby, for example, before the gear device 20 is driven for the first time, the oil 90 can be easily supplied to the bearing 25c as lubricating oil. In the present embodiment, the front side (+X side) portion of the inner opening 51d is provided at the same position as a part of the rear side (-X side) portion of the bearing 25c in the front-rear direction.

[0051] In the present embodiment, the inner opening 51d is located on the rear side (-X side) of the intermediate axis J2 and on the front side (+X side) of the differential axis J3. The intermediate axis J2 is the rotation axis of the second gear 24b and the third gear 24c, and the differential axis J3 is the rotation axis of the ring gear 22a. That is, in the front-rear direction (X-axis direction), the position of the inner opening 51d is between the rotation axes of the second gear 24b and the ring gear 22a as two gears whose rotation axes are spaced apart in the front-rear direction. The position of the inner opening 51d is between the rotation axes of the third gear 24c and the ring gear 22a as two gears whose rotation axes are spaced apart in the front-rear direction. Therefore, when an operator or the like injects oil 90 into the inside of the gear housing 32 through the first through portion 51, the oil 90 can be more easily supplied to the second gear 24b, the third gear 24c, the ring gear 22a, and the bearings supporting these gears.

[0052] The inner opening 51d is located above the central axis J1, the intermediate axis J2, and the differential axis J3. The inner opening 51d is located below the outer opening 51c. In the present embodiment, the position of the inner opening 51d in the front-rear direction (X-axis direction) is the same as the position of the outer opening 51c in the front-rear direction.

[0053] At least a part of the inner opening 51d is located above at least one gear. Therefore, when an operator or the like injects oil 90 into the inside of the gear housing 32 through the first through-hole 51, the oil 90 flowing into the inside of the gear housing 32 from the inner opening 51d can be easily supplied to the at least one gear from above. In the present embodiment, the entire inner opening 51d is located above the third gear 24c. Therefore, as shown in FIG. 7, the oil 90 flowing into the gear housing 32 from the inner opening 51d can be easily supplied to the third gear 24c from above. In the present embodiment, since the third gear 24c is located on one axial side (+Y side) of the second gear 24b, the third gear 24c is arranged closer to the lid wall portion 32a in the axial direction than the second gear 24b. Therefore, the inner opening 51d opens into the space portion located above the third gear 24c in the internal space of the gear housing 32. Thereby, the oil 90 flowing into the gear housing 32 from the inner opening 51d can be more suitably supplied to the third gear 24c from above.

[0054] As shown in FIG. 3, the inner opening 51d is located above the meshing portion 24d of the third gear 24c and the ring gear 22a as a pair of meshing gears when viewed in the axial direction. Therefore, when an operator or the like injects oil 90 into the inside of the gear housing 32 through the first through-hole 51, the oil 90 flowing into the inside of the gear housing 32 from the inner opening 51d can be easily supplied to the meshing portion 24d of the third gear 24c and the ring gear 22a.

[0055] As shown in FIG. 6, in the present embodiment, at least a part of the first through portion 51 overlaps the second gear 24b in the axial direction. Therefore, for example, compared with the case where the entire first through portion 51 does not overlap the second gear 24b in the axial direction, it is possible to suppress the increase in the size of the gear housing 32 in the direction orthogonal to the axial direction, that is, for example, the vertical direction. In the present embodiment, the lower end portion of the inner opening 51d overlaps the upper portion of the second gear 24b in the axial direction. In this specification, "a certain object overlaps another object in a certain direction" means that when viewed in a certain direction, at least a part of a certain object is provided at a position overlapping at least a part of another object.

[0056] As shown in FIG. 3, in the present embodiment, the first through portion 51 has a groove portion 51g. The groove portion 51g connects the inside of the concave portion 51b and the inside of the bearing holding portion 35c. Thereby, in the present embodiment, the first through portion 51 is connected to the inside of the bearing holding portion 35c. Therefore, when an operator or the like injects the oil 90 into the gear housing 32 through the first through portion 51, the oil 90 flowing through the first through portion 51 can be supplied to the bearing holding portion 35c. Therefore, the oil 90 can be supplied to the bearing 25c held by the bearing holding portion 35c.

[0057] In the present embodiment, the bearing holder 35c that holds the bearing 25c for rotatably supporting the upper gear is located above the bearing holder 35a that holds the bearing 25a for rotatably supporting the lower gear. That is, in the present embodiment, the bearing holder 35c connected to the first through portion 51 can be rephrased as an "upper bearing holder" that holds the bearing 25c for rotatably supporting the second gear 24b and the third gear 24c. The intermediate axis J2, which is the rotation axis of the second gear 24b and the third gear 24c, is located above the central axis J1, which is the rotation axis of the first gear 24a. As a result, the bearing holder 35c that holds the bearing 25c for rotatably supporting the second gear 24b and the third gear 24c is arranged above the bearing holder 35a that holds the bearing 25a for rotatably supporting the first gear 24a. Therefore, even when the gear device 20 is driven and the oil 90 in the first reservoir 32d is stirred up by the ring gear 22a, the oil 90 may be less likely to be supplied into the bearing holder 35c than into the bearing holder 35a. However, in the present embodiment, since the first through portion 51 is connected to the bearing holder 35c, when an operator or the like injects the oil 90 into the inside of the gear housing 32 through the first through portion 51, the oil 90 can be supplied into the bearing holder 35c. Therefore, before the gear device 20 is driven, the oil 90 can be supplied to the bearing 25c held by the bearing holder 35c. For example, when the gear device 20 is driven, it is possible to suppress a shortage of the oil 90 in the bearing 25c. That is, the gear device 20 can be driven in a state where the oil 90 is supplied and lubricated to the bearing 25c in advance. At least a part of the oil 90 that has flowed into the bearing holder 35c may flow into the bearing holder 35a and be supplied to the bearing 25a.

[0058] The groove portion 51g is provided on the surface of the lid wall portion 32a on the other axial side (-Y side). The groove portion 51g is a groove that is recessed on one axial side (+Y side) and opens on the other axial side. In the present embodiment, the groove portion 51g extends obliquely downward and forward (+X side) from the recessed portion 51b. Instead of the groove portion 51g, a hole connecting the inside of the recessed portion 51b and the inside of the bearing holding portion 35c may be provided in the lid wall portion 32a. The first through portion 51 may lead to the inside of another bearing holding portion that holds a bearing for rotatably supporting the gear. The first through portion 51 may lead to the inside of the bearing holding portion 35a or may lead to the inside of the bearing holding portion 35e.

[0059] The gear housing 32 has a second through portion 52 that connects the inside of the gear housing 32 and the outside of the gear housing 32. The second through portion 52 is a hole that axially penetrates the lid wall portion 32a. The second through portion 52 is, for example, circular in shape when viewed axially. The opening portion 52a of the second through portion 52 that opens to the outside of the gear housing 32 is closed by the second plug member 42. The second plug member 42 is, for example, a screw member having the same shape as the first plug member 41. The second plug member 42 is detachably attached to the opening portion 52a. Note that the second plug member 42 may be non-detachably attached to the opening portion 52a. The opening portion 52a opens on the surface of the lid wall portion 32a on one axial side (+Y side).

[0060] The second through-hole 52 is provided in the lower portion of the gear housing 32. Therefore, by using the second through-hole 52 as an oil drain hole for draining the oil 90 in the gear housing 32, the oil 90 stored in the first storage portion 32d of the gear housing 32 can be suitably drained to the outside of the gear housing 32. The second through-hole 52 is located below the central axis J1, the intermediate axis J2, and the differential axis J3. The second through-hole 52 is provided at the lower end portion of the lid wall portion 32a. The second through-hole 52 is located below the entire ring gear 22a. The second through-hole 52 is located on the rear side (-X side) of the first through-hole 51. The second through-hole 52 is located below the differential axis J3 when viewed in the axial direction. The position of the second through-hole 52 in the front-rear direction (X-axis direction) includes the position of the differential axis J3 in the front-rear direction.

[0061] In the present embodiment, the gear housing 32 has a third through-hole 53 that connects the inside of the gear housing 32 and the outside of the gear housing 32. The third through-hole 53 is a hole that axially penetrates the lid wall portion 32a. The third through-hole 53 is, for example, circular in shape when viewed in the axial direction. The opening 53a of the third through-hole 53 that opens to the outside of the gear housing 32 is closed by the third plug member 43. The third plug member 43 is, for example, a screw member having the same configuration as the first plug member 41. The third plug member 43 is detachably attached to the opening 53a. Note that the third plug member 43 may be non-detachably attached to the opening 53a. The opening 53a opens to the surface on one axial side (+Y side) of the lid wall portion 32a.

[0062] The third through-hole 53 is located below the first through-hole 51 and above the second through-hole 52. Therefore, when an operator or the like injects oil 90 into the gear housing 32 through the first through-hole 51 and when discharging the oil 90 from the gear housing 32 through the second through-hole 52, it is easy to check the amount of the oil 90 in the gear housing 32 through the third through-hole 53. Specifically, for an operator, the amount of the oil 90 in the gear housing 32 can be checked by visually observing the inside of the gear housing 32 through the third through-hole 53. For a device performing the operation, for example, the amount of the oil 90 in the gear housing 32 can be checked by measuring the amount of the oil 90 in the gear housing 32 through the third through-hole 53 using a sensor or the like.

[0063] In the present embodiment, the third through-hole 53 is located above the central axis J1 and the differential axis J3 and below the intermediate axis J2. The third through-hole 53 is located on the rear side (-X side) of the first through-hole 51 and the second through-hole 52. The third through-hole 53 is located on the rear side of the differential axis J3.

[0064] As shown in FIG. 1, the gear housing 32 has a mounting portion 34 that protrudes in the axial direction. The mounting portion 34 protrudes axially from the surface on one axial side (+Y side) of the lid wall portion 32a. In the present embodiment, the mounting portion 34 is cylindrical. The mounting portion 34 is provided with a threaded hole 34a that extends from the end face on one axial side toward the other axial side (-Y side). In the present embodiment, a plurality of mounting portions 34 are provided. When the drive device 100 is mounted on a vehicle, a part of the vehicle body is attached to the plurality of mounting portions 34, for example. The end portion on one axial side of the mounting portion 34 is located on one axial side of the end portion on one axial side of the convex portion 33. In other words, the end portion on one axial side of the convex portion 33 is located on the other axial side of the end portion on one axial side of the mounting portion 34. Therefore, even if the convex portion 33 is provided to provide the first through-hole 51, when the drive device 100 is mounted on the vehicle, it is possible to prevent the convex portion 33 from contacting the vehicle body.

[0065] The control device 60 is located above the motor housing 31. The control device 60 is attached to the motor housing 31. The control device 60 includes a circuit board 60a and a case 60b. The case 60b houses the circuit board 60a inside. The case 60b has a substantially rectangular parallelepiped box shape. A part of the case 60b and the housing main body 30a are, for example, respective parts of a single member. The entire case 60b may be separate from the housing main body 30a. The circuit board 60a is electrically connected to the stator 12. Thereby, the control device 60 is electrically connected to the motor 10. An inverter circuit for supplying power to the stator 12 is provided on the circuit board 60a.

[0066] The control device 60 has connector portions 61 and 62 that protrude in the axial direction. In the present embodiment, the connector portions 61 and 62 protrude axially on one side (+Y side) in the axial direction from the surface on one side of the case 60b. Each of the connector portion 61 and the connector portion 62 is provided in a pair with a space therebetween in the front-rear direction (X-axis direction). The pair of connector portions 62 are located on the rear side (-X side) of the pair of connector portions 61. Wiring of an external device (not shown) is electrically connected to each of the connector portions 61 and 62.

[0067] As shown in FIG. 4, the ends on one side (+Y side) in the axial direction of the connector portions 61 and 62 are located on the other side (-Y side) in the axial direction from the outer opening 51c. That is, in the present embodiment, the entire outer opening 51c is provided at a position different from that of the connector portions 61 and 62 in the axial direction orthogonal to the vertical direction. Therefore, when connecting the pipe member 91 to the outer opening 51c, it can be made less likely to be obstructed by the connector portions 61 and 62. Thereby, the operation of injecting the oil 90 into the gear housing 32 can be facilitated. In the present embodiment, the entire outer opening 51c is provided at a position different from that of the connector portions 61 and 62 in the front-rear direction (X-axis direction) orthogonal to the vertical direction. Therefore, when connecting the pipe member 91 to the outer opening 51c, it can be made less likely to be obstructed by the connector portions 61 and 62. In the present embodiment, the position of the outer opening 51c in the front-rear direction is between the pair of connector portions 61 in the front-rear direction.

[0068] In addition, in this specification, the phrase "the entire outer opening is provided at a position different from the connector portion in a direction orthogonal to the vertical direction" means that the entire outer opening may be provided at a position different from the connector portion in at least one of a plurality of directions that can be defined as a direction orthogonal to the vertical direction. The entire outer opening 51c may be provided at a position different from the connector portions 61 and 62 only in one of the axial direction and the front-rear direction, or may be provided at a position different from the connector portions 61 and 62 in a direction different from the axial direction and the front-rear direction among the directions orthogonal to the vertical direction.

[0069] Hereinafter, embodiments different from the above-described embodiments will be described. In the description of each of the following embodiments, for components that are the same as those described above the description of each embodiment, the description may be omitted by appropriately assigning the same reference numerals. Also, for portions corresponding to each part of the configuration described above the description of each embodiment, the same name will be given and different reference numerals will be assigned to explain the differences from the above-described configuration, and the description of the same points as the above-described configuration may be omitted. Note that, as the configurations omitted in the following embodiments, within a non-contradictory range, configurations similar to those described above the description of each embodiment can be adopted.

[0070] <Second Embodiment> As shown in FIG. 8, in the gear device 220 of the drive device 200 of the present embodiment, the convex portion 233 and the first through portion 251 provided on the convex portion 233 are located below the convex portion 33 and the first through portion 51 of the first embodiment. In the present embodiment, the outer opening 251c of the first through portion 251 overlaps at least one of the plurality of gears in the axial direction. Therefore, it is easy to reduce the size of the gear device 220 in the direction orthogonal to the axial direction, that is, the vertical direction and the front-rear direction. In the present embodiment, the outer opening 251c overlaps the second gear 24b in the axial direction. In the present embodiment, the outer opening 251c is located below the upper end portion of the gear housing 32. Therefore, in a configuration where the control device 60 is provided above the motor housing 31, when an operator or the like injects oil 90 into the gear housing 32 through the inside of the first through portion 251, it is possible to suppress interference between the pipe member 91 connected to the outer opening 251c and the wiring connected to the control device 60 and the connector portions 61, 62 of the control device 60.

[0071] In the present embodiment, the inner opening 251d of the first through portion 251 overlaps at least one of the plurality of gears in the axial direction. Therefore, it is easier to further reduce the size of the gear device 220 in the direction orthogonal to the axial direction, that is, the vertical direction and the front-rear direction. In the present embodiment, the inner opening 251d overlaps the second gear 24b, the third gear 24c, and the ring gear 22a in the axial direction. The inner opening 251d overlaps the bearing 25c in the axial direction. The lower end portion of the inner opening 251d is located below the intermediate axis J2 and above the central axis J1 and the differential axis J3. Other configurations of the first through portion 251 are the same as those of the first through portion 51 in the first embodiment. Other configurations of the gear device 220 are the same as those of the gear device 20 in the first embodiment. Other configurations of the drive device 200 are the same as those of the drive device 100 in the first embodiment.

[0072] <Third Embodiment> As shown in FIG. 9, in the gear device 320 of the drive device 300 of the present embodiment, the convex portion 333 and the first through portion 351 provided on the convex portion 333 are located below and on the front side (+X side) of the convex portion 233 and the first through portion 251 of the second embodiment. In the present embodiment, the outer opening 351c of the first through portion 351 overlaps with the first gear 24a in the axial direction. Therefore, similar to the second embodiment, the gear device 320 can be miniaturized in the direction orthogonal to the axial direction, that is, the vertical direction and the front-rear direction. The outer opening 351c is located below the central axis J1 when viewed in the axial direction.

[0073] In the present embodiment, the inner opening 351d of the first through portion 351 does not overlap with any of the gears in the axial direction. The inner opening 351d is located below the central axis J1 when viewed in the axial direction. Other configurations of the first through portion 351 are the same as those of the first through portion 51 in the first embodiment. Other configurations of the gear device 320 are the same as those of the gear device 20 in the first embodiment. Other configurations of the drive device 300 are the same as those of the drive device 100 in the first embodiment.

[0074] <Fourth Embodiment> As shown in FIG. 10, in the gear device 420 of the drive device 400 of the present embodiment, the gear housing 432 has a cylindrical portion 36a, first ribs 437a and 437b, and a second rib 437c. The cylindrical portion 36a projects axially on one side (+Y side) from the peripheral edge of the through hole 36 on the surface of the lid wall portion 32a on one side in the axial direction. The cylindrical portion 36a is cylindrical with the differential axis J3 as the center.

[0075] The first ribs 437a, 437b and the second rib 437c are provided on the surface on one axial side (+Y side) of the lid wall portion 32a. The first ribs 437a, 437b are substantially annular ribs surrounding the differential axis J3. In the radial direction centered on the differential axis J3, the first ribs 437a, 437b are located outside the cylindrical portion 36a. In the radial direction centered on the differential axis J3, the first rib 437b is located outside the first rib 437a. In the middle of the first rib 437a, a third through portion 53 and a third plug member 43 are provided. In the middle of the first rib 437b, a convex portion 433 and a first through portion 451 are provided.

[0076] The second rib 437c is a rib linearly extending outward from the cylindrical portion 36a in the radial direction centered on the differential axis J3. A plurality of second ribs 437c are provided at intervals in the circumferential direction centered on the differential axis J3. The plurality of second ribs 437c are arranged at equal intervals over one circumference in the circumferential direction centered on the differential axis J3. The plurality of second ribs 437c intersect the first rib 437a. The outer end of one of the plurality of second ribs 437c is connected to the convex portion 433. The outer ends of the remaining second ribs 437c are connected to the first rib 437b. The second rib 437c connected to the convex portion 433 is a second rib 437c extending rearward (-X side) from the cylindrical portion 36a.

[0077] In the present embodiment, the convex portion 433 and the first through portion 451 provided in the convex portion 433 are located on the rear side (-X side) of the differential axis J3. The convex portion 433 and the first through portion 451 are provided at the rear end of the gear housing 432. One of the first rib 437b and the plurality of second ribs 437c is connected to the convex portion 433. Therefore, the rigidity of the convex portion 433 can be improved. Accordingly, it is possible to suppress deformation of the outer opening 451c of the first through portion 451 provided in the convex portion 433, and it is possible to suppress the difficulty of connecting the pipe member 91 to the outer opening 451c.

[0078] In this embodiment, the outer opening 451c overlaps with the ring gear 22a in the axial direction. Therefore, similar to the second embodiment, it is easy to miniaturize the gear device 420 in the direction orthogonal to the axial direction, that is, the vertical direction and the front-rear direction. The outer opening 451c overlaps with the clearance 32e between the radially outer surface of the ring gear 22a and the radially inner surface 32c of the gear housing 432 in the axial direction. The radially inner surface 32c is the inner peripheral surface of the gear peripheral wall portion 32b.

[0079] The inner opening 451d overlaps with the clearance 32e between the radially outer surface of the ring gear 22a and the radially inner surface 32c of the gear housing 432 in the axial direction. Therefore, when an operator or the like injects oil 90 into the gear housing 432 through the first through portion 451, it is easy to supply the oil 90 flowing into the inside of the gear housing 432 from the inner opening 451d to the tooth portion of the ring gear 22a. In this specification, the "radially outer surface of the gear" means the outer surface of the gear in the radial direction centered on the rotation axis of the gear, including the tip surface of the tooth portion of the gear. That is, the radially outer surface of the ring gear 22a is the outer surface of the ring gear 22a in the radial direction centered on the differential axis J3, including the tip surface of the tooth portion of the ring gear 22a. In this embodiment, the inner opening 451d overlaps with the ring gear 22a in the axial direction. The lower end of the inner opening 451d is located below the central axis J1 and the differential axis J3.

[0080] The other configurations of the first through portion 451 are the same as the other configurations of the first through portion 51 in the first embodiment. The other configurations of the gear device 420 are the same as the other configurations of the gear device 20 in the first embodiment. The other configurations of the drive device 400 are the same as the other configurations of the drive device 100 in the first embodiment.

[0081] <Fifth Embodiment> As shown in FIG. 11, the gear device 520 of the drive device 500 according to the present embodiment includes a second reservoir 570. The second reservoir 570 is a reservoir located above the bottom of the gear housing 532 inside the gear housing 532. The second reservoir 570 can store oil 90 inside. In the present embodiment, the second reservoir 570 has a trough shape that opens upward. Note that the second reservoir 570 may have any shape as long as it can store the oil 90 inside. The second reservoir 570 may have a shape that opens in a direction orthogonal to the vertical direction. Inside the second reservoir 570, for example, a part of the oil 90 scooped up from inside the first reservoir 32d by the ring gear 22a enters.

[0082] The second reservoir 570 is located above the first reservoir 32d. In the present embodiment, the second reservoir 570 is located above a plurality of gears, that is, the first gear 24a, the second gear 24b, the third gear 24c, and the ring gear 22a. The second reservoir 570 is connected to the gear housing 532. At least a part of the second reservoir 570 and the gear cover 30c are, for example, parts of a single member. Note that the entire second reservoir 570 may be separate from the gear housing 532. The second reservoir 570 has a bottom wall portion 571 and a pair of side wall portions 572. The pair of side wall portions 572 project upward from both edge portions in the front-rear direction (X-axis direction) of the bottom wall portion 571, respectively.

[0083] In this embodiment, connection flow path portions 538c and 538e are provided in the gear housing 532. The connection flow path portions 538c and 538e are provided, for example, in the gear cover 30c. The connection flow path portion 538c connects the inside of the second reservoir portion 570 and the inside of the bearing holding portion 35c. The connection flow path portion 538c obliquely extends downward and forward (+X side) from the bottom wall portion 571 and connects to the inside of the bearing holding portion 35c. A part of the oil 90 in the second reservoir portion 570 flows through the connection flow path portion 538c and flows into the bearing holding portion 35c. Thereby, the oil 90 is supplied to the bearing 25c. The connection flow path portion 538e connects the inside of the second reservoir portion 570 and the inside of the bearing holding portion 35e. The connection flow path portion 538e extends downward from the bottom wall portion 571 and connects to the inside of the bearing holding portion 35e. A part of the oil 90 in the second reservoir portion 570 flows through the connection flow path portion 538e and flows into the bearing holding portion 35e. Thereby, the oil 90 is supplied to the bearing 25e. Note that at least a part of the oil 90 that has flowed into the inside of the bearing holding portion 35c from the inside of the second reservoir portion 570 may flow into the bearing holding portion 35a that holds the bearing 25a that rotatably supports the first gear shaft 23a and be supplied to the bearing 25a.

[0084] In this embodiment, the first through portion 551 is connected to the second reservoir portion 570. Therefore, when an operator or the like injects the oil 90 into the gear housing 532 through the first through portion 551, the oil 90 flowing through the first through portion 551 can be made to flow into the second reservoir portion 570. Thereby, when an operator or the like injects the oil 90 into the gear housing 532 through the first through portion 551, the oil 90 can be made to flow from the second reservoir portion 570 to the portion connected to the second reservoir portion 570. Specifically, in this embodiment, the oil 90 can be made to flow from the second reservoir portion 570 to the connection flow path portions 538c and 538e. Thereby, when an operator or the like injects the oil 90 into the gear housing 532 through the first through portion 551, the oil 90 can be supplied to the bearings 25c and 25e held by the bearing holding portions 35c and 35e.

[0085] In the present embodiment, the first through portion 551 and the second storage portion 570 are arranged side by side in the front-rear direction (X-axis direction) orthogonal to both the axial direction and the vertical direction. Therefore, even if the second storage portion 570 is provided, it is possible to suppress an increase in the size of the gear device 520 in the axial direction and the vertical direction. The first through portion 551 is located on the front side (+X side) of the second storage portion 570. The first through portion 551 is provided in the lid wall portion 32a, for example.

[0086] The first through portion 551 has a first hole portion 551a and a second hole portion 551b. The first hole portion 551a extends downward from the upper surface of the gear housing 532. The upper end portion of the first hole portion 551a is an outer opening portion 551c that opens upward. The second hole portion 551b extends obliquely rearward (-X side) and downward from the lower end portion of the first hole portion 551a. The rear end portion of the second hole portion 551b is connected to the side wall portion 572 located on the front side (+X side) of the pair of side wall portions 572. The rear end portion of the second hole portion 551b is an inner opening portion 551d that opens into the second storage portion 570. In the present embodiment, the inner opening portion 551d opens rearward. The surface located on the lower side of the inner surface of the second hole portion 551b is the surface located on the lower side of the inner surface of the first through portion 551, and is an inclined surface 551e that is located lower as it approaches the inner opening portion 551d. The inclined surface 551e is located lower as it faces the rear side. The inclined surface 551e can preferably guide the oil 90 that has flowed into the first through portion 551 from the outer opening portion 551c into the second storage portion 570.

[0087] Other configurations of the first through portion 551 are the same as other configurations of the first through portion 51 in the first embodiment. Other configurations of the gear device 520 are the same as other configurations of the gear device 20 in the first embodiment. Other configurations of the drive device 500 are the same as other configurations of the drive device 100 in the first embodiment.

[0088] <Sixth Embodiment> As shown in FIG. 12, in the gear device 620 of the drive device 600 of the present embodiment, an attachment hole 632f that penetrates the lid wall portion 32a of the gear housing 632 in the front-rear direction (X-axis direction) is provided in the lid wall portion 32a. The attachment hole 632f is provided in the lower portion of the lid wall portion 32a. The end portion on the rear side (-X side) of the attachment hole 632f is a suction port 632e that opens to the inner surface of the gear housing 632. The suction port 632e opens to the inner surface of the lid wall portion 32a, that is, the rear surface. The suction port 632e opens into the first storage portion 32d.

[0089] The gear device 620 includes a pump 680 that sucks the oil 90 in the gear housing 632 through the suction port 632e. The pump 680 is an electric pump. The pump 680 is attached to the outer surface of the lid wall portion 32a, that is, the front side (+X side) surface. The pump 680 has a connection portion 681 that is inserted into the suction port 632e from the outside of the gear housing 632. The connection portion 681 is cylindrical and opens to the rear side (-X side).

[0090] In the present embodiment, the convex portion 633 and the first through portion 651 are located above the pump 680. The convex portion 633 is the same as the convex portion 33 of the first embodiment except for the points where the positions are different. The first through portion 651 is the same as the first through portion 51 of the first embodiment except for the points where the positions are different. The inner opening 651d of the first through portion 651 is located above the suction port 632e on the inner surface of the lid wall portion 32a, that is, the rear side (-X side) surface. In the present embodiment, the inner opening 651d is arranged side by side with the suction port 632e. Therefore, when an operator or the like injects the oil 90 into the gear housing 632 through the first through portion 651, the oil 90 flowing into the gear housing 632 from the inner opening 651d can be made to flow near the suction port 632e. Thereby, for example, when the pump 680 is driven for the first time, it is possible to suppress a shortage of the oil 90 around the suction port 632e and suppress the pump 680 from idling.

[0091] The distance between the inner opening 651d and the suction port 632e is smaller than the vertical dimension of the inner opening 651d. The distance between the inner opening 651d and the suction port 632e is preferably smaller than the inner diameter of the suction port 632e. Other configurations of the gear device 620 are the same as those of the gear device 20 in the first embodiment. Other configurations of the drive device 600 are the same as those of the drive device 100 in the first embodiment.

[0092] The present invention is not limited to the above-described embodiments, and other configurations and other methods can be adopted within the scope of the technical idea of the present invention. The first through-hole may have any configuration as long as it has an inner opening and an outer opening and connects the inside and the outside of the gear housing. The outer opening that opens to the outside of the gear housing may have any configuration as long as it is closed by the first plug member and is provided at a position different from that of the plurality of gears in the first direction. In the second embodiment described above, the outer opening 251c may axially overlap with the third gear 24c instead of the second gear 24b, or may axially overlap with both the second gear 24b and the third gear 24c. The inner opening that opens to the inside of the gear housing may have any configuration. The inner opening may be provided at any position. The shape of the outer opening and the shape of the inner opening are not particularly limited.

[0093] The direction in which the outer opening opens and the direction in which the inner opening opens are not particularly limited. The outer opening may open in the front-rear direction (X-axis direction) of the above-described embodiment, or may open in the axial direction (Y-axis direction) of the above-described embodiment. The inner opening may open in the vertical direction, or may open in the front-rear direction (X-axis direction) of the above-described embodiment.

[0094] When an inclined surface is provided on the lower surface of the inner surface of the first through-hole, the lower surface of the inner surface of the first through-hole may have a surface other than the inclined surface. The inclined surface provided on the lower surface of the inner surface of the first through-hole may be inclined in any direction as long as it is located lower as it approaches the inner opening.

[0095] The first through-hole may be a through-hole for any use. The first through-hole may be a through-hole used as an oil drain hole. The first through-hole may be a through-hole used for the same purpose as the third through-hole 53 in the first embodiment described above. A plurality of first through-holes may be provided. The first through-hole may be provided at any part of the gear housing. The first through-hole may be provided in a part of the gear housing 32 of the first embodiment described above, which is constituted by the housing main body 30a. The second through-hole may be provided in the lower wall portion of the gear housing, or may be provided in the side wall portion 32f of the first embodiment described above. The third through-hole may be provided in the side wall portion 32f of the first embodiment described above. The second through-hole and the third through-hole may not be provided.

[0096] The gear device may include a pressure adjusting portion provided in the gear housing. The pressure adjusting portion may have any structure as long as it can adjust the pressure in the gear housing. The pressure adjusting portion may be a breather valve or a vent filter. For example, in the first embodiment described above, the pressure adjusting portion may be provided on the side where the central axis J1 is located with respect to the differential axis J3 in the front-rear direction (X-axis direction), that is, the front side (+X side), rather than the first through-hole 51. According to this configuration, the pressure adjusting portion can be arranged farther away from the ring gear 22a in the front-rear direction than the first through-hole 51. Thereby, it can be made difficult for the oil 90 lifted by the ring gear 22a to reach the pressure adjusting portion. Therefore, it is possible to suppress the oil 90 from leaking to the outside of the gear housing 32 through the pressure adjusting portion.

[0097] When the pressure adjusting portion is provided in the gear housing, for example, the first through-hole 51 and the pressure adjusting portion in the first embodiment described above may have a portion provided at the same position in the vertical direction. According to this configuration, it is possible to suppress the gear device 20 from increasing in size in the vertical direction.

[0098] The first direction in which the rotation axes of the plurality of gears extend is not particularly limited as long as it is a direction orthogonal to the vertical direction, and may be a direction different from the axial direction of the motor connected to the gear device. The first direction in which the rotation axes of the plurality of gears extend may be, for example, the front-rear direction (X-axis direction) in the above-described embodiment. The fluid accommodated in the gear housing may be a fluid other than oil, such as water. In the above-described embodiment, the intermediate axis J2 may be located below the central axis J1.

[0099] The uses of the gear device and the drive device are not particularly limited. The drive device may be mounted on a vehicle for uses other than rotating an axle, for example, or may be mounted on a device other than a vehicle.

[0100] Note that the present technology can be configured as follows. (1) A gear device including: a plurality of gears that rotate around a rotation axis extending in a first direction orthogonal to the vertical direction; and a gear housing that houses the plurality of gears therein, the gear housing having a first through portion that connects the inside of the gear housing and the outside of the gear housing, the first through portion having an inner opening that opens into the inside of the gear housing and an outer opening that opens to the outside of the gear housing, the outer opening being closed by a first plug member, and the entire outer opening being provided at a position different from the plurality of gears in the first direction. (2) The gear device according to (1), wherein the outer opening opens upward. (3) The gear device according to (1) or (2), wherein the inner opening opens in the first direction. (4) The gear device according to (3), wherein a surface located on the lower side of the inner surface of the first through portion has an inclined surface that is located lower as it approaches the inner opening. (5) The gear device according to any one of (1) to (4), wherein the inner opening and at least one of the plurality of gears have a portion provided at the same position in a second direction orthogonal to both the first direction and the vertical direction. (6) It includes a bearing that rotatably supports the gear, and the inner opening and the bearing have a portion provided at the same position as each other in a second direction orthogonal to both the first direction and the vertical direction. The gear device according to any one of (1) to (5). (7) The plurality of gears includes two gears whose rotation axes are spaced apart in a second direction orthogonal to both the first direction and the vertical direction. In the second direction, the position of the inner opening is the position between the rotation axes of the two gears. The gear device according to any one of (1) to (6). (8) The outer opening overlaps at least one of the plurality of gears in the first direction. The gear device according to any one of (1) to (7). (9) At least a part of the inner opening is located above at least one of the gears. The gear device according to any one of (1) to (8). (10) It includes a speed reduction device and a differential device connected to the speed reduction device. The speed reduction device has a gear shaft extending in the first direction, a first gear that is the gear provided on the gear shaft, a second gear that is the gear meshing with the first gear, and a third gear that is the gear rotating around the same rotation axis as the second gear. The whole of the inner opening is located above the third gear. The outer diameter of the second gear is larger than the outer diameter of the third gear. At least a part of the first through portion overlaps the second gear in the first direction. The gear device according to (9). (11) It includes a storage portion located above the bottom of the gear housing inside the gear housing. The storage portion opens upward, and the first through portion is connected to the storage portion. The gear device according to any one of (1) to (10). (12) The first through portion and the storage portion are arranged side by side in a second direction orthogonal to both the first direction and the vertical direction. The gear device according to (11). (13) The whole of the inner opening is provided at a position different from the plurality of gears in the first direction. The gear device according to any one of (1) to (12). (14) The plurality of gears includes a pair of meshing gears, The inner opening is located above the meshing portion between the pair of gears when viewed in the first direction. The gear device according to any one of (1) to (13). (15) The inner opening overlaps with the gap between the radially outer surface of the gear and the radially inner surface of the gear housing in the first direction. The gear device according to any one of (1) to (14). (16) A pump is provided for sucking the fluid in the gear housing through a suction port that opens on the inner surface of the gear housing. The inner opening is arranged side by side with the suction port. The gear device according to any one of (1) to (15). (17) The gear housing has a second through portion that connects the inside of the gear housing and the outside of the gear housing. The opening of the second through portion that opens to the outside of the gear housing is closed by a second plug member. The second through portion is provided in the lower portion of the gear housing. The gear device according to any one of (1) to (16). (18) The gear housing has a third through portion that connects the inside of the gear housing and the outside of the gear housing. The opening of the third through portion that opens to the outside of the gear housing is closed by a third plug member. The third through portion is located below the first through portion and above the second through portion. The gear device according to (17). (19) The gear housing has a bearing holding portion that holds a bearing for rotatably supporting the gear. The first through portion leads to the inside of the bearing holding portion. The gear device according to any one of (1) to (18). (20) The plurality of gears includes a lower gear and an upper gear whose rotation axis is located above the lower gear. The bearing holding portion includes an upper bearing holding portion that holds an upper bearing for rotatably supporting the upper gear. The first through portion leads to the inside of the upper bearing holding portion. The gear device according to (19). A drive device comprising: the gear device according to any one of (1) to (20); and a motor connected to the gear device. (22) The drive device according to (21), further comprising a control device electrically connected to the motor, the control device having a connector portion protruding in the first direction, and the entire outer opening portion being provided at a position different from the connector portion in a direction orthogonal to the vertical direction.

[0101] As described above, the configurations and methods described in this specification can be appropriately combined within a range that does not conflict with each other.

Explanation of Reference Numerals

[0102] 10… motor, 20, 220, 320, 420, 520, 620… gear device, 21… reduction device, 22… differential device, 23a… first gear shaft (gear shaft), 24a… first gear (lower gear), 24b… second gear (upper gear), 24c… third gear (upper gear), 25a, 25b, 25c, 25e… bearing, 30… housing, 32, 432, 532, 632… gear housing, 32c… radially inner surface, 32e… gap, 35c… bearing holding portion (upper bearing holding portion), 41… first plug member, 42… second plug member, 43… third plug member, 51, 251, 351, 451, 551, 651… first through portion, 51c, 251c, 351c, 451c, 551c… outer opening, 51d, 251d, 351d, 451d, 551d, 651d, 651e… inner opening, 51e, 551e… inclined surface, 52… second through portion, 52a, 53a… opening, 53… third through portion, 60… control device, 61, 62… connector portion, 90… oil (fluid), 100, 200, 300, 400, 500, 600… drive device, 570… second storage portion (storage portion), 632e… suction port, 680… pump, J1… central axis (rotation axis), J2… intermediate axis (rotation axis), J3… differential axis (rotation axis)

Claims

1. A plurality of gears that rotate around a rotation axis extending in a first direction orthogonal to the vertical direction, A gear housing that houses the plurality of gears inside, Comprising, The gear housing has a first through-hole that connects the inside of the gear housing and the outside of the gear housing, The first through-hole is, An inner opening that opens inside the gear housing, An outer opening that opens outside the gear housing, Having, The outer opening is closed by a first plug member, The entire outer opening is provided at a position different from the plurality of gears in the first direction, a gear device.

2. The outer opening opens upward, the gear device according to claim 1.

3. The inner opening opens in the first direction, the gear device according to claim 1.

4. Among the inner surfaces of the first through-hole, the surface located on the lower side has an inclined surface that is located on the lower side as it approaches the inner opening, the gear device according to claim 3.

5. The inner opening and at least one of the gears have a portion provided at the same position in a second direction orthogonal to both the first direction and the vertical direction, the gear device according to claim 1.

6. Comprising a bearing that rotatably supports the gear, The inner opening and the bearing have a portion provided at the same position in a second direction orthogonal to both the first direction and the vertical direction, the gear device according to claim 1.

7. The plurality of gears include two gears arranged at intervals in a second direction in which the rotation axis is orthogonal to both the first direction and the vertical direction, In the second direction, the position of the inner opening is the position between the rotation axes of the two gears, the gear device according to claim 1.

8. The outer opening overlaps at least one of the plurality of gears in the first direction, the gear device according to claim 1.

9. At least a part of the inner opening is located above at least one of the gears, the gear device according to claim 1.

10. A speed reduction device, A differential device connected to the speed reduction device, Comprising, The speed reduction device is, A gear shaft extending in the first direction, A first gear that is the gear provided on the gear shaft, A second gear that is the gear meshing with the first gear, A third gear that is the gear rotating around the same rotation axis as the second gear, Having, The whole of the inner opening is located above the third gear, The outer diameter of the second gear is larger than the outer diameter of the third gear, At least a part of the first through portion overlaps with the second gear in the first direction. The gear device according to claim 9.

11. A storage portion is provided inside the gear housing and is located above the bottom of the gear housing, The storage portion is open upward, The first through portion is connected to the storage portion. The gear device according to claim 1.

12. The first through portion and the storage portion are arranged side by side in a second direction orthogonal to both the first direction and the vertical direction. The gear device according to claim 11.

13. The whole of the inner opening is provided at a position different from the plurality of gears in the first direction. The gear device according to claim 1.

14. The plurality of gears include a pair of meshing gears, The inner opening is located above the meshing portion of the pair of gears when viewed in the first direction. The gear device according to claim 1.

15. The inner opening overlaps with the gap between the radially outer surface of the gear and the radially inner surface of the gear housing in the first direction. The gear device according to claim 1.

16. A pump is provided for sucking the fluid in the gear housing through a suction port opening on the inner surface of the gear housing, The inner opening is arranged side by side with the suction port. The gear device according to claim 1.

17. The gear housing has a second through portion connecting the inside of the gear housing and the outside of the gear housing, The opening of the second through portion that opens to the outside of the gear housing is closed by a second plug member, The second through portion is provided in the lower portion of the gear housing. The gear device according to claim 1.

18. The gear housing has a third through portion connecting the inside of the gear housing and the outside of the gear housing, The opening of the third through portion that opens to the outside of the gear housing is closed by a third plug member, The third through portion is located below the first through portion and above the second through portion. The gear device according to claim 17.

19. The gear housing has a bearing holding portion for holding a bearing that rotatably supports the gear, The first through portion is connected to the inside of the bearing holding portion. The gear device according to claim 1.

20. The plurality of gears include a lower gear, an upper gear whose rotation axis is located above the lower gear, and the bearing holding portion includes an upper bearing holding portion that rotatably supports the upper gear, The first through portion is connected to the inside of the upper bearing holding portion. The gear device according to claim 19.

21. A gear device according to any one of claims 1 to 20, and a motor connected to the gear device, comprising a drive device.

22. comprising a control device electrically connected to the motor, the control device having a connector portion protruding in the first direction, The entire outer opening is provided at a position different from the connector portion in a direction orthogonal to the vertical direction. The drive device according to claim 21.

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