TWI839041B - Drive device and electric vehicle - Google Patents

Abstract

The present invention provides a drive device and an electric vehicle, which can suppress the leakage of lubricating material from the opposing part to the outside of the gear cover. The motor of the drive device has: a shaft extending axially along the center axis, and a drive gear that can rotate around the center axis together with the shaft. The gear part that transmits the torque of the motor to the output part has: a first gear meshed with the drive gear, and a gear cover that surrounds the drive gear and at least a part of the first gear when viewed from the axial direction. The first gear cover and the second gear cover of the gear cover are arranged to be opposite to each other in the axial direction. The opposing portion where the other axial end portion of the first gear cover and the one axial end portion of the second gear cover are axially opposed has a first opposing portion that is opposed to a first engaging portion of the first gear and the drive gear in a direction perpendicular to the axial direction with a gap therebetween.

Description

Drive device and electric vehicle

The present invention relates to a driving device and an electric vehicle

In the past, there is a known drive device that uses a lubricating material to lubricate the gear. For example, a gear assembly including a small gear and a large gear meshing with the small gear is installed between the center housing and the right housing (Japanese Patent Publication No. 2014-144768).

Usually, meshing gears are meshed with each other through lubricating materials such as grease. At the meshing portion of the gears, the grease is pushed out in the axial direction extending from the rotation axis of the gears and is retained on the axial side of the meshing portion of the gears.

[Prior art literature]

[Patent Literature]

Patent document 1: Japanese Patent Publication No. 2014-144768

Here, in the meshing part of the gears, lubricating materials such as grease tend to accumulate on one side and the other side axially closer to the meshing part. Therefore, if the opposing parts of the two gear covers that house the meshing gears are located on one side or the other side axially closer to the meshing part of the gears, the lubricating material may leak from the opposing parts of the gear covers to the outside thereof.

The purpose of the present invention is to suppress the leakage of lubricating material from the opposing portion to the outside of the gear cover.

An exemplary drive device of the present invention includes: a motor, an output portion and a gear portion. The output portion outputs torque to the outside. The gear portion transmits the torque of the motor to the output portion. The motor has: a shaft and a drive gear. The shaft extends axially along a center axis. The drive gear can rotate with the shaft around the center axis. The gear portion has: a first gear and a gear cover. The first gear is engaged with the drive gear. When viewed axially, the gear cover surrounds the drive gear and at least a portion of the first gear. The gear cover has: a first gear cover, a second gear cover and an opposing portion. The second gear cover is axially arranged opposite to the first gear cover. In the opposing portion, the other axial end of the first gear cover and the one axial end of the second gear cover are axially opposed. The opposing portion has a first opposing portion. The first opposing portion is opposed to the first engagement portion where the first gear and the drive gear are engaged with a gap in a direction perpendicular to the axial direction.

The exemplary electric vehicle of the present invention has the above-mentioned driving device.

According to the exemplary drive device and electric vehicle of the present invention, it is possible to suppress the leakage of the lubricating material from the opposing portion to the outside of the gear cover.

100: Electric vehicles

101: Car body

102:Wheels

102f:Front wheel

102r:Rear wheel

103: Power transmission mechanism

104: Power supply department

105: Crank

105a: Crankshaft

106: Pedal

107: Handle

108: Saddle

10: Driving device

20: Motor

21: Motor shaft

22: Drive gear

23: Motor bearing part

30: Output section

31: Output gear

33: Output bearing part

34: One-way clutch

40: Gear unit

41: First gear shaft

411: First bearing part

412: Second bearing part

42: Second gear shaft

421: Third bearing part

422: Fourth bearing part

423: One-way clutch

424: Bearing part

43: First gear

44: Second gear

45: Third gear

46: Fourth gear

50: Shell

500:Inner space

51: First plate component

511: Inner surface

512: First column

52: Second plate component

521: Inner surface

522: Second column

53: First barrel

531: End face

54: Second tube

541: End face

55: protrusion

56: Support components

561: First perforation

562: Second perforation

563: Motor support hole

60: Gear cover

61: First gear cover

62: Second gear cover

621: Side panel

622: Wall

6221: Ribs

623: Opening

6241:Front side end

6242: Front side elastic part

6251: Rear side end

6252: Rear side elastic part

63: Opposing part

631: First opposing part

632: Second opposing part

633: Third opposing part

64: Concave part

65: Cover

E1: The first part of the fusion

E2: The second part of the fusion

J1: Center axis

J2: First intermediate shaft

J3: Second intermediate shaft

J4: Output shaft

Rt: Rotation direction

Br: Bearing part

Sr: Torque detection unit

FIG1 is a schematic diagram of an electric vehicle according to an embodiment of the present invention.

Figure 2 is a three-dimensional diagram of the drive device.

Figure 3 is a three-dimensional view of the interior of the drive device after the second plate component and the second cylinder are removed.

Figure 4 is a three-dimensional view of the interior of the drive device after the second plate component and the second cylinder are removed.

Figure 5 is a schematic three-dimensional diagram showing the gears of the gear unit meshing with each other.

Figure 6 is a cross-sectional view of the drive device.

Figure 7 is a cross-sectional view showing the crankshaft and output portion.

Figure 8 is a three-dimensional view of the first plate component and the first cylinder.

Figure 9 is a three-dimensional view of the second plate component and the second cylinder.

Figure 10 is a three-dimensional view of the supporting component that supports the motor and the gear part and is fixed to the first cylinder part.

FIG. 11A is a side view showing a structural example of a gear cover.

FIG. 11B is a side view showing another structural example of the gear cover.

Figure 12 is an enlarged cross-sectional view of the opening of the gear cover.

Below, the exemplary implementation of the present invention is described in detail with reference to the attached drawings.

In this specification, when describing the drive device 10, the direction parallel to the first intermediate shaft J2 of the first gear shaft 41 of the drive device 10 shown in FIG. 1 is referred to as the "axial direction". In addition, the direction orthogonal to a predetermined axis such as the first intermediate shaft J2 is referred to as the "radial direction", and the direction along an arc centered on the predetermined axis is referred to as the "circumferential direction".

In addition, based on the state of being installed on the electric vehicle 100, the direction of travel of the electric vehicle 100 is set to "front F", and the opposite direction is set to "rear B". In addition, "upper U", "lower D", "left L", and "right R" are defined in the state facing forward. In addition, in this specification, the left and right directions are parallel to the axial direction. That is, the left and right directions correspond to the "axial direction" of the present invention. In addition, "left L" corresponds to "one axial direction" of the present invention. "Right R" corresponds to "the other axial direction" of the present invention.

In addition, the directions in the following description are defined for the convenience of explanation and may not be consistent with the direction of the drive device 10 actually used.

<Electric Vehicles 100>

FIG1 is a schematic diagram of an electric vehicle 100 according to an embodiment of the present invention. In this embodiment, the electric vehicle 100 is an electric power-assisted bicycle that assists the user in stepping on a pedal 106.

The electric vehicle 100 has a drive device 10. In the electric vehicle 100, as described later, the first engagement portion E1 between the drive gear 22 of the motor 20 in the drive device 10 and the first gear 43 of the gear unit 40 can suppress the lubricating material such as grease from leaking to the outside of the gear cover 60.

In addition, as shown in FIG1 , the electric vehicle 100 has a vehicle body 101, two wheels 102, a power transmission mechanism 103, and a power supply unit 104.

The vehicle body 101 includes a handlebar 107 and a saddle 108. Two wheels 102, a power transmission mechanism 103, a drive device 10 and a power supply unit 104 are mounted on the vehicle body 101. The two wheels 102 are mounted on the front of the vehicle body 101 as a front wheel 102f and mounted on the rear as a rear wheel 102r. The rear wheel 102r is connected to the power transmission mechanism 103.

The power transmission mechanism 103 includes: a crank 105 mounted on a crankshaft 105a and a pedal 106. In addition, the power transmission mechanism 103 also includes: a driving gear 22 mounted on the output portion 30 described later of the drive device 10, a driven gear mounted on the rear wheel 102r, and a chain connecting the driving gear 22 and the driven gear (all not shown). The crank 105 is fixed to the crankshaft 105a rotatably mounted on the vehicle body 101. In addition, a pedal 106 is rotatably mounted on the front end of the crank 105.

The drive device 10 is mounted on the power transmission mechanism 103. The drive device 10 transmits torque from the output unit 30 (see FIG. 2 ) to the power transmission mechanism 103. The torque transmitted from the drive device 10 is transmitted to the rear wheel 102r via the power transmission mechanism 103. That is, the electric vehicle 100 has a power transmission mechanism 103 that transmits the output from the output unit 30 to the wheel 102.

In addition, the output portion 30 of the drive device 10 and the output gear 31 described later are formed by a single component, but the present invention is not limited to this. For example, the output portion 30 may also serve as the crankshaft 105a. That is, as the drive device 10, a structure that can assist the rotation of the wheel 102 caused by the force of the user can be widely adopted.

The power supply unit 104 is mounted on the vehicle body 101. The power supply unit 104 is, for example, a battery, and supplies power to the motor 20 described later of the drive device 10 via the wiring shown in the figure. That is, the electric vehicle 100 has: the drive device 10, and the power supply unit 104 that supplies power to the motor 20 of the drive device 10.

In the electric vehicle 100, a torque is applied to the crankshaft 105a by a user sitting on a saddle 108 stepping on a pedal 106. The torque applied to the crankshaft 105a is transmitted to the rear wheel 102r via the output unit 30 and the power transmission mechanism 103. The rear wheel 102r rotates by the transmitted torque, and the electric vehicle 100 travels. In addition, the drive device 10 detects the torque applied to the crankshaft 105a, and applies the torque from the output unit 30 to the power transmission mechanism 103 as needed. The torque transmitted from the output unit 30 is added to the torque used for traveling the electric vehicle 100. That is, the drive device 10 assists the electric vehicle 100 with the torque required for driving as needed.

<Drive device 10>

FIG. 2 is a perspective view of the drive device 10. FIG. 3 is a perspective view of the interior of the drive device 10 after the second plate member 52 and the second cylinder 54 are removed. FIG. 4 is a perspective view of the interior of the drive device 10 after the second plate member 52 and the second cylinder 54 are removed. FIG. 5 is a schematic perspective view showing the gears of the gear part 40 meshing with each other. FIG. 6 is a cross-sectional view of the drive device 10.

As shown in FIGS. 2 to 6 , the drive device 10 includes a motor 20, an output unit 30, a gear unit 40, and a housing 50.

<Motor 20>

The motor 20 is a DC brushless motor. The motor 20 is driven by electric power from the power supply unit 104. The motor 20 has: a rotor (not shown) rotating around the center axis J1, and a stator (not shown) located radially outward based on the center axis J1 of the rotor. That is, the motor 20 is an inner rotor type motor in which the rotor is rotatably arranged inside the stator. In addition, the motor 20 is not limited to the inner rotor type motor, but can also be an outer rotor type motor. In addition, the motor 20 has a motor shaft 21. The motor shaft 21 is fixed to the rotor, extends axially along the center axis J1, and rotates around the center axis J1. In addition, as shown in FIG. 5, the motor shaft 21 protrudes to the left L from the main body of the motor 20.

A drive gear 22 is arranged at the front end of the motor shaft 21, that is, the end on the left L side. The drive gear 22 is fixed to the motor shaft 21. The drive gear 22 can rotate with the motor shaft 21 around the center axis J1. The motor 20 has a drive gear 22. In addition, the drive gear 22 can be fixed to the motor shaft 21 by a wide range of fixing methods that can be firmly fixed, such as press-fitting, welding, and bonding.

FIG7 is a cross-sectional view showing the crankshaft 105a and the output portion 30. As shown in FIG3, FIG5, and FIG7, the crankshaft 105a extends along the output shaft J4. The left end of the crankshaft 105a protrudes to the left L of the housing 50. In addition, the right end of the crankshaft 105a protrudes to the right R of the housing 50. As described above, left and right cranks 105 are fixed to both ends of the crankshaft 105a (see FIG1).

Furthermore, the output unit 30 and the torque detection unit Sr are arranged on the crankshaft 105a in a direction parallel to the extension of the output shaft J4. To further explain, the output unit 30 and the torque detection unit Sr are arranged around the crankshaft 105a.

The torque detection unit Sr detects the torque acting on the crankshaft 105a. That is, the drive device 10 also has: a torque detection unit Sr that detects the torque acting on the crankshaft 105a. In the drive device 10 of this embodiment, the torque detection unit Sr has: a sleeve fixed on the crankshaft 105a, and an outer cylinder portion surrounding the radial outer side based on the center axis J4 of the sleeve.

The outer cylinder has a protrusion Sr1 that protrudes outward in a radial direction based on the center axis J4, and the protrusion Sr1 is fixed to the fixing portion 560 of the support member 56 (see FIG. 3 ). That is, a part of the torque detection portion Sr is fixed to the support member 56. By configuring in this way, the components for installing the torque detection portion Sr can be omitted, and the drive device 10 can be miniaturized. In addition, the torque detection portion Sr is not limited to the above structure, and a wide range of structures that can accurately detect the torque of the rotating crankshaft 105a can be adopted.

<Output unit 30>

The output portion 30 extends along the output shaft J4 parallel to the center axis J1. That is, the output portion 30 extends parallel to the motor shaft 21. The output portion 30 has an output gear 31. The output portion 30 covers the periphery of the crankshaft 105a at the end portion on the right R side of the crankshaft 105a. The power transmission mechanism 103 is connected to the output portion 30 (refer to FIG. 1). And, the output portion 30 outputs torque to the power transmission mechanism 103. That is, the drive device 10 has an output portion 30 that outputs torque to the outside. In addition, the output portion 30 is connected to the crankshaft 105a via the output bearing portion 33 and the one-way clutch 34 (refer to FIG. 7). By installing in this way, the torque from the crankshaft 105a is transmitted to the power transmission mechanism 103 only when the torque is transmitted from the crankshaft 105a to the output unit 30.

In addition, the output bearing portion 33 uses a ball bearing as a bearing component, but it is not limited to this. A bearing structure that can support the output portion 30 so that it can rotate around the crankshaft 105a can be widely adopted. As the output bearing portion 33, one bearing component is used, but it is not limited to this, and it can also be a structure using multiple bearing components. In the following, when it is recorded as a "bearing portion", it is the same structure.

The crankshaft 105a and the output portion 30 are rotatably supported by the housing 50 via the bearing portion Br. To be more specific, the end portion on the left L side of the crankshaft 105a is rotatably supported by the inner surface 521 of the second plate member 52 described later of the housing 50 via the bearing portion Br. In addition, the output portion 30 covers the end portion on the right R side of the crankshaft 105a and is rotatably supported by the inner surface 511 of the first plate member 51 described later of the housing 50 via the bearing portion Br. As described above, the crankshaft 105a is connected to the output portion 30 via the output bearing portion 33 and the one-way clutch 34. Therefore, the right R side end of the crankshaft 105a is rotatably supported on the first plate member 51 of the housing 50 via the output bearing 33, the output portion 30, and the bearing Br.

<Gear unit 40>

The gear unit 40 transmits the torque of the motor shaft 21 to the output unit 30. In other words, the gear unit 40 transmits the torque of the motor 20 to the output unit 30. The gear unit 40 is a deceleration mechanism that decelerates when transmitting the torque from the motor shaft 21 to the output unit 30. The gear unit 40 has a first gear shaft 41, a second gear shaft 42, a first gear 43, a second gear 44, a third gear 45, a fourth gear 46 and a gear cover 60.

The first gear shaft 41 extends along the first intermediate shaft J2 parallel to the central axis J1. The first gear shaft 41 is cylindrical and can rotate around the first intermediate shaft J2. The first gear shaft 41 is supported on the housing 50 in a rotatable manner via a first bearing portion 411 and a second bearing portion 412 that are separately arranged in the direction along the first intermediate shaft J2.

In addition, the second gear shaft 42 extends along the second intermediate shaft J3 parallel to the central axis J1 and the first intermediate shaft J2. The second gear shaft 42 is cylindrical and can rotate around the second intermediate shaft J3. The second gear shaft 42 is supported on the housing 50 in a rotatable manner via the third bearing 421 and the fourth bearing 422 that are separately arranged in the direction along the second intermediate shaft J3.

The first gear 43 and the second gear 44 are fixed on the first gear shaft 41. The first gear 43 can rotate around the first intermediate shaft J2 parallel to the central axis J1 and mesh with the drive gear 22. The second gear 44 is arranged on the right side R of the first gear 43 and can rotate with the first gear 43 around the first intermediate shaft J2. The third gear 45 is fixed on the second gear shaft 42. The third gear 45 meshes with the second gear 44.

The outer diameter of the first gear 43 is larger than the outer diameter of the second gear 44. In other words, the number of teeth of the first gear 43 is greater than the number of teeth of the second gear 44. That is, the gear part 40 has: a first gear shaft 41 to which the first gear 43 and the second gear 44 having a smaller number of teeth than the first gear 43 are fixed.

Therefore, the torque transmitted from the drive gear 22 to the first gear shaft 41 via the first gear 43 is reduced in speed according to the gear ratio between the first gear 43 and the second gear 44 and transmitted to the second gear shaft 42. In addition, the number of teeth of the second gear 44 is less than the number of teeth of the third gear 45. Therefore, the torque of the first gear shaft 41 is also reduced in speed according to the gear ratio between the second gear 44 and the third gear 45 and transmitted to the second gear shaft 42.

In addition, the so-called torque is transmitted after being reduced by the gear ratio, which means that the speed is reduced by the gear ratio, that is, deceleration, and the torque is amplified and transmitted, and the same applies to the following.

The third gear 45 and the fourth gear 46 are formed separately. The fourth gear 46 is formed integrally with the second gear shaft 42. The third gear 45 is rotatably supported on the second gear shaft 42 via the one-way clutch 423 and the bearing 424 (see Figure 6). By installing in this way, the torque is transmitted to the second gear shaft 42 only when the torque is transmitted from the second gear 44 to the third gear 45.

Furthermore, the fourth gear 46 is meshed with the output gear 31. The outer diameter of the third gear 45 is larger than the outer diameter of the fourth gear 46. In other words, the number of teeth of the third gear 45 is greater than the number of teeth of the fourth gear 46. Therefore, the torque transmitted from the fourth gear 46 to the second gear shaft 42 via the output gear 31 is decelerated according to the ratio of the number of teeth of the third gear 45 to the fourth gear 46. In addition, the number of teeth of the output gear 31 is greater than the number of teeth of the fourth gear 46. Therefore, the torque of the second gear shaft 42 is also decelerated according to the ratio of the number of teeth of the fourth gear 46 to the output gear 31 and transmitted to the output part 30.

<Shell 50>

Next, the detailed description of the housing 50 is described with reference to the attached drawings. FIG. 8 is a perspective view of the first plate member 51 and the first cylinder 53. FIG. 9 is a perspective view of the second plate member 52 and the second cylinder 54. As shown in FIG. 3 to FIG. 6, etc., the housing 50 has an internal space 500. The motor 20, a part of the output part 30, and the gear part 40 are accommodated in the internal space 500. That is, the housing 50 has an internal space 500, and the motor 20, a part of the output part 30, and the gear part 40 are accommodated in the internal space.

As shown in Figures 2 to 9, the housing 50 has: a first plate member 51, a second plate member 52, a first tube 53, and a second tube 54. As shown in Figure 6, the housing 50 has: a first plate member 51 and a second plate member 52 facing the internal space 500 and axially opposite to each other. To further explain, the first plate member 51 is arranged on the right R of the internal space 500, and the second plate member 52 is arranged on the left L of the internal space 500.

As shown in FIG8 , the first cylinder 53 protrudes axially to the left L from the inner surface 511 of the inner space 500 facing the first plate member 51. That is, the housing 50 has a first cylinder 53 extending axially from the outer edge of the inner surface 511 of the first plate member 51 that is opposite to the second plate member 52. In addition, in the present embodiment, the first cylinder 53 and the first plate member 51 are formed by a single member, but are not limited to this, and may also be formed by different members and fixed by fixing methods such as bonding and screw fixing.

As shown in FIG9 , the second cylinder 54 protrudes axially to the right R from the inner surface 521 of the inner space 500 facing the second plate member 52. That is, the housing 50 has a second cylinder 54 extending axially from the outer edge of the inner surface 521 of the second plate member 52 that is opposite to the first plate member 51. In addition, in the present embodiment, the second cylinder 54 and the second plate member 52 are formed by a single component, but are not limited to this, and may also be formed by different components and fixed by fixing methods such as bonding and screw fixing.

As shown in FIG. 1 and FIG. 6, at least a portion of the axially opposed end surfaces of the first tube 53 and the second tube 54 are in contact with each other. More specifically, the end surface 531 on the left L side of the first tube 53 and the end surface 541 on the right R side of the second tube 54 are axially opposed. In addition, the end surface 531 of the first tube 53 and the end surface 541 of the second tube 54 are in contact with each other except for the portion in contact with the supporting member 56 described later. Thus, an internal space 500 surrounded by the shell 50 is formed.

In addition, the first barrel 53 has a protrusion 55. The protrusion 55 protrudes inward from the first barrel 53. Here, "protruding inward" refers to a structure that protrudes from the first barrel 53 facing the inner space 500 to the inner space 500. In addition, in the present embodiment, four protrusions 55 are provided on the first barrel 53, but this is not limited to this, as long as the number can firmly fix the support member 56. By adopting a structure in which the protrusion 55 protrudes inward from the first barrel 53, the rigidity of the protrusion 55 becomes higher. As a result, the protrusion 55 is not easy to bend, and the fixing strength of the support member 56 can be improved.

The protrusion 55 extends axially, and the end on the right R side is connected to the first plate member 51. That is, the protrusion 55 is connected to the first plate member 51 while protruding from the first cylinder 53. In addition, the protrusion 55 is connected to the first plate member 51, and any of the following situations can be cited: the protrusion 55 and the first plate member 51 are formed by a single member, the protrusion 55 is fixed to the first plate member 51, and the protrusion 55 is in contact with the first plate member 51. By configuring in this way, the axial force of the protrusion 55 can be supported by the first plate member 51, so that the axial movement and deformation of the supporting member 56 fixed to the protrusion 55 can be suppressed.

In addition, in the housing 50 of the present embodiment, the protrusion 55 and the first plate member 51 are formed by a single member, but the present invention is not limited thereto. For example, in the case where the first plate member 51 and the first cylinder 53 are formed by different members and fixed, the protrusion 55 may be in contact with the first plate member 51 but not fixed. In addition, the protrusion 55 may also be a structure not connected to the first plate member 51.

In addition, the protrusion 55 is formed on the first tube 53, but can also be formed on the second tube 54, or can be formed on both sides. That is, the housing 50 also has: a protrusion 55 protruding inward from at least one of the first tube 53 and the second tube. When the protrusion 55 is formed on the second tube 54, the protrusion 55 can also extend axially, and the end on the left L side is connected to the second plate member 52. That is, the protrusion 55 is connected to the second plate member 52 when it protrudes from the second tube 54.

By configuring in this way, the second plate member 52 can support the axial force of the protrusion 55, thereby suppressing the axial movement and deformation of the supporting member 56 fixed to the protrusion 55.

In addition, the housing 50 has a supporting member 56 disposed inside the internal space 500. In addition, in the present embodiment, the supporting member 56 is accommodated inside the internal space 500, but is not limited thereto, and may be partially disposed outside the housing 50 or exposed to the outside. That is, the housing 50 has a supporting member 56 at least partially disposed inside the internal space 500.

The support member 56 is a plate extending in a direction intersecting the axial direction. In the housing 50 of the present embodiment, the support member 56 supports the motor 20 and the gear portion 40. FIG. 10 is a three-dimensional view of the support member 56 that supports the motor 20 and the gear portion 40 and is fixed to the first cylinder portion 53. As shown in FIG. 10, the support member 56 is fixed to the protrusion 55 formed on the first cylinder portion 53 by fasteners such as screws. In addition, the support member 56 is clamped in the axial direction by the bottom of the first column portion 512 and the bottom of the second column portion 522 described later. Furthermore, the support member 56 is fastened together by fasteners such as screws inserted into the first column portion 512 and the second column portion 522 from the outside of the housing 50. That is, the supporting member 56 is fixed to the protruding portion 55, the first column portion 512 and the second column portion 522.

The support member 56 is fixed to the protrusion 55, for example, by screws. In addition, the screws are passed through the support member 56 sandwiched by the first column 512 and the second column 522, and the first column 512, the second column 522 and the support member 56 are fixed by tightening together. Thus, the support member 56 is fixed in the internal space 500 of the housing 50.

The housing 50 has a first column portion 512 that protrudes axially to the left L from an area surrounded by the first tube portion 53 on the inner surface 511 of the first plate member 51. In addition, the housing 50 has a second column portion 522 that protrudes axially to the right R from an area surrounded by the second tube portion 54 on the inner surface 521 of the second plate member 52.

The first column 512 and the second column 522 are cylindrical with bottoms. When the end surface 531 of the first cylinder 53 and the end surface 541 of the second cylinder 54 are brought into contact and fixed, the bottom of the first column 512 and the bottom of the second column 522 are axially opposed to each other, and the supporting member 56 is sandwiched from both sides of the axial direction. In addition, in the housing 50 of the present embodiment, the column is formed on both the first plate member 51 and the second plate member 52, but it is not limited to this, and it can also be formed on either the first plate member 51 or the second plate member 52.

That is, the housing 50 also has: column portions 512, 522 protruding axially toward the internal space 500 from at least one of the area surrounded by the first tube portion 53 of the first plate member 51 and the area surrounded by the second tube portion 54 of the second plate member 52. By configuring in this way, the supporting portion of the supporting member 56 can be dispersed, and the stress concentration on the supporting member 56 can be suppressed. Therefore, even if the rigidity of the supporting member 56 is low, it can support the motor 20 and the gear portion 40, and the supporting member 56 can be miniaturized and simplified. As a result, the proportion of the supporting member 56 in the internal space 500 can be reduced, and as a result, the drive device 10 can be miniaturized.

In addition, only the first column 512 may be provided, and the support member 56 may be fixed to the first column 512. That is, the column 512 only contacts the surface on the right R side of the support member 56. By configuring in this way, the surface on the other side of the support member 56 contacts the column 512, and a structure in which neither the gear shaft nor the column 512 is arranged on the left L side can be formed. Thus, the housing 50 can be miniaturized or an area for arranging other components can be formed in the internal space of the housing, and the drive device 10 itself can be miniaturized.

The support member 56 has: a first through hole 561, a second through hole 562 and a motor support hole 563 (refer to FIG. 3 and FIG. 4). The motor 20 is fixed to the first plate member 51. Moreover, the motor shaft 21 passes through the motor support hole 563 and is rotatably supported on the support member 56 via the motor bearing 23. That is, the motor shaft 21 extends in the axial direction and is rotatably supported on the support member 56 via the motor bearing 23. To further explain, the outer ring of the motor bearing 23 is fixed to the motor support hole 563, and the motor shaft 21 is fixed to the inner ring. By configuring in this way, the positional deviation between the motor shaft 21 and the first gear shaft 41 and the second gear shaft 42 can be suppressed. As a result, the torque of the motor shaft 21 can be correctly transmitted to the gear unit 40.

In addition, the first gear shaft 41 is rotatably supported on the inner surface 521 of the second plate member 52 via the first bearing portion 411. The outer ring of the second bearing portion 412 is fixed to the first through hole 561 of the support member 56, and the first gear shaft 41 is fixed to the inner ring (refer to FIG. 6). Thus, the first gear shaft 41 is rotatably supported on the second plate member 52 via the first bearing portion 411, and is rotatably supported on the support member 56 via the second bearing portion 412.

The second gear shaft 42 is rotatably supported on the inner surface 511 of the first plate member 51 through the fourth bearing portion 422. The outer ring of the fourth bearing portion 422 is fixed to the second through hole 562, and the second gear shaft 42 is fixed to the inner ring (see Figure 6). Thus, the second gear shaft 42 is rotatably supported on the first plate member 51 through the fourth bearing portion 422, and is rotatably supported on the supporting member 56 through the third bearing portion 421. That is, the gear portion 40 has a second gear shaft 42, which is parallel to the first gear shaft 41.

By configuring in this way, the second gear shaft 42 of the gear part 40 supported by the housing 50 and the support member 56 can be shortened, and the gear part 40 can be miniaturized accordingly. Thus, the housing 50 can be miniaturized or an area for configuring other components can be formed in the internal space 500 of the housing 50, and the drive device 10 can be miniaturized. In addition, since the second gear shaft 42 can be shortened, the torsion of the second gear shaft 42 can be suppressed. Thus, the delay of torque transmission caused by the torsion can be suppressed.

The second gear shaft 42 is rotatably supported on the support member 56 and the first plate member 51 through the third bearing portion 421 and the fourth bearing portion 422. Therefore, the second gear shaft 42 does not protrude further to the left L than the third gear 45. Thus, in the internal space 500, a space can be provided between the third gear 45 and the second plate member 52. The first gear 43 can be arranged in the space. Therefore, the gear portion 40 can be densely arranged, and the components can be efficiently arranged in the internal space 500. Thus, the drive device 10 can be miniaturized.

In addition, in the gear unit 40, the first gear 43 can be arranged at a position overlapping with the second gear shaft 42 when viewed from the direction in which the second intermediate shaft J3 extends. That is, a portion of the first gear 43 faces the axial end surface of the second gear shaft 42. Since the first gear 43 and the second gear shaft 42 do not interfere with each other, the diameter of the first gear 43 can be increased without increasing the internal space 500. Thus, the reduction ratio of the gear unit 40 can be increased without increasing the size of the drive device 10.

In addition, the right end of the first gear shaft 41 is rotatably supported on the support member 56 via the second bearing portion 412. Therefore, the first gear shaft 41 does not protrude to the right R than the support member 56. Therefore, when viewed from the direction in which the first intermediate shaft J2 extends, a portion of the motor 20 can be arranged in a portion that is closer to the right R than the support member 56 and overlaps with the first gear shaft 41. As a result, the components in the internal space 500 can be densely arranged, and the housing 50, that is, the drive device 10 can be miniaturized.

<Gear cover 60>

Next, the gear cover 60 will be described with reference to FIG. 4 and FIG. 11A to FIG. 11B. FIG. 11A is a side view showing a structural example of the gear cover 60. FIG. 11B is a side view showing another structural example of the gear cover 60. FIG. 11A and FIG. 11B are views of the gear cover 60, for example, when viewed from the direction X of FIG. 4.

The gear cover 60 surrounds at least a portion of the drive gear 22 and the first gear 43 when viewed from the axial direction. As described above, the gear portion 40 has the gear cover 60.

The gear cover 60 includes a first gear cover 61, a second gear cover 62, and an opposing portion 63.

When viewed from the axial direction, the first gear cover 61 surrounds the left L side portion of the drive gear 22 and the left L side portion of the first gear 43. Specifically, a portion of the first gear cover 61 is arranged radially outward relative to the center axis J1 of the drive gear 22, surrounds the left L side portion of the radial outer end portion of the drive gear 22 (i.e., the portion where the gear is arranged), and extends circumferentially relative to the center axis J1. In addition, another portion of the first gear cover 61 is arranged radially outward of the first gear 43 based on the first intermediate shaft J2, surrounds the left L side portion of the radial outer end portion of the first gear 43 (i.e., the portion where the gear is arranged), and extends circumferentially based on the first intermediate shaft J2.

In addition, in this embodiment, the first gear cover 61 is fixed to the inner surface 521 of the second plate member 52. However, the example does not exclude the structure in which the first gear cover 61 is not fixed to the second plate member 52.

The second gear cover 62 surrounds the right R side portion of the drive gear 22 and the right R side portion of the first gear 43 when viewed axially. The second gear cover 62 is arranged axially opposite to the first gear cover 61. The second gear cover 62 is fixed to the support member 56. The second gear cover 62 is arranged at a position closer to the right R than the first gear cover 61, and when viewed axially, the second gear cover 62 surrounds the right R side portion of the drive gear 22 and the right R side portion of the first gear 43. In addition, when viewed axially, the second gear cover 62 also surrounds the third gear 45.

In the opposing portion 63, the right R side end of the first gear cover 61 and the left L side end of the second gear cover 62 are axially opposed. The first gear cover 61 and the second gear cover 62 are arranged opposite to each other when the internal space 500 of the housing 50 is formed by connecting the first cylinder 53 and the second cylinder 54.

The opposing portion 63 has a first opposing portion 631. The first opposing portion 631 is opposed to the first engaging portion E1 where the first gear 43 and the drive gear 22 engage with each other with a gap in a direction perpendicular to the axial direction. For example, the first opposing portion 631 and the first engaging portion E1 are opposed to each other with a gap in the circumferential direction based on the center axis J1. The first opposing portion 631 is located closer to one circumferential side and the other circumferential side of the first engaging portion E1 based on the center axis J1. Here, "one circumferential side based on the center axis J1" refers to the clockwise direction from the left L toward the right R and centered on the center axis J1 in the circumferential direction based on the center axis J1. "The other side in the circumferential direction based on the center axis J1" refers to the counterclockwise direction from the left L toward the right R with the center axis J1 as the center in the circumferential direction based on the center axis J1. In addition, it can also be said that the two are opposed to each other with a gap separated in the circumferential direction based on the first intermediate axis J2. The first opposing portion 631 is located closer to one side of the circumferential direction based on the first intermediate axis J2 and the other side of the circumferential direction than the first engaging portion E1. Here, "one side of the circumferential direction based on the first intermediate axis J2" refers to the clockwise direction from the left L toward the right R with the first intermediate axis J2 as the center in the circumferential direction based on the first intermediate axis J2. "The other side of the circumferential direction based on the first intermediate axis J2" means the counterclockwise direction from the left L to the right R with the first intermediate axis J2 as the center in the circumferential direction based on the first intermediate axis J2.

For example, the first opposing portion 631 is arranged at a position closer to the right R than the end of the left L side of the driving gear 22 and the end of the left L side of the first gear 43 in the first engaging portion E1, and is arranged at a position closer to the left L than the end of the right R side of the driving gear 22 and the end of the right R side of the first gear 43. In the first engaging portion E1, a lubricating material such as grease is pressed out to the left L and the right R thereof. By configuring the first opposing portion 631 relative to the drive gear 22 and the first gear 43 as described above, the lubricant is less likely to reach the first opposing portion 631 compared to the structure in which the first opposing portion 631 is configured to the left L or right R of the drive gear 22 and the first gear 43 in the first engagement portion E1 described above. Therefore, the lubricant is less likely to leak from the first opposing portion 631. Therefore, it is possible to suppress the lubricant from leaking from the opposing portion 63 to the outside of the gear cover 60.

In addition, since the first opposing portion 631 is opposed to the first engaging portion E1 with a gap in a direction perpendicular to the axial direction, the rotation of the drive gear 22 and the first gear 43 is not hindered.

In addition, the opposing portion 63 also has a second opposing portion 632. In the second opposing portion 632, on the right side R of the first opposing portion 631, the end of the right side R of the first gear cover 61 and the end of the left side L of the second gear cover 62 are axially opposed.

In addition, the opposing portion 63 also has a third opposing portion 633. The third opposing portion 633 connects one circumferential end portion of the first opposing portion 631 based on the first intermediate axis J2 and the other circumferential end portion of the second opposing portion 632 based on the first intermediate axis J2. In addition, the "circumferential side" here refers to the clockwise direction from the left L toward the right R and centered on the first intermediate axis J2 in the circumferential direction based on the first intermediate axis J2. The "other circumferential side" refers to the counterclockwise direction from the left L toward the right R and centered on the first intermediate axis J2 in the circumferential direction based on the first intermediate axis J2. In addition, in Figures 11A and 11B, the third opposing portion 633 extends in the left-right direction. However, the direction in which the third opposing portion 633 extends is not limited to the example described above. For example, the third opposing portion 633 may also extend in one or the other circumferential direction from the left L toward the right R.

In addition, in the opposing portion 63, the end of the right R side of the first gear cover 61 and the end of the left L side of the second gear cover 62 may be opposed to each other with a gap, or may be in contact.

For example, regarding the axially opposed configuration, in FIG. 11A , the first gear cover 61 and the second gear cover 62 are axially opposed with a gap therebetween. In addition, the first gear cover 61 may be axially opposed with the second gear cover 62 with a gap therebetween at least one of the first opposing portion 631 and the second opposing portion 632. In this way, since the first gear cover 61 and the second gear cover 62 are not in contact with each other in the axial direction, it is possible to easily configure one of the first gear cover 61 and the second gear cover 62 relative to the other without requiring strict dimensional accuracy, as compared to a structure in which the two are in contact with each other in the axial direction.

On the other hand, in FIG. 11B , at least a portion of the first gear cover 61 is in axial contact with the second gear cover 62. In addition, the first gear cover 61 may be in axial contact with the second gear cover 62 at least at one of the first opposing portion 631 and the second opposing portion 632. In this way, the lubricating material is difficult to leak from the opposing portion 63 through the axial contact of the two at the opposing portion 63. In addition, unlike the present embodiment, when the first gear cover 61 not fixed to the second plate member 52 is directly arranged opposite to the second gear cover 62, the first gear cover 61 can be positioned axially relative to the second gear cover 62.

In addition, regarding the circumferentially opposed configuration based on the first intermediate shaft J2, in FIG. 11A, in the third opposing portion 633, the first gear cover 61 and the second gear cover 62 are circumferentially opposed with a gap therebetween. In this way, even if the opposing portion 63 extends in a stepped manner in the circumferential direction, strict dimensional accuracy is not required, and it is easy to configure one of the first gear cover 61 and the second gear cover 62 relative to the other.

On the other hand, in FIG. 11B , at least a portion of the first gear cover 61 contacts the second gear cover 62 in the third opposing portion 633. Thus, the lubricating material is difficult to leak from the opposing portion 63 through the contact of the two in the third opposing portion 633. In addition, unlike the present embodiment, when the first gear cover 61 that is not fixed to the second plate member 52 is directly disposed opposite to the second gear cover 62, the first gear cover 61 can be positioned relative to the second gear cover 62 in the circumferential direction based on the first intermediate shaft J2.

The contact and separation of the first gear cover 61 and the second gear cover 62 are independent in the first opposing portion 631 and the second opposing portion 632 and the third opposing portion 633. For example, the first gear cover 61 and the second gear cover 62 may contact each other at at least one of the first opposing portion 631 and the second opposing portion 632, and the first gear cover 61 and the second gear cover 62 may be separated from each other at the third opposing portion 633. Alternatively, the first gear cover 61 and the second gear cover 62 may be separated from each other at at least one of the first opposing portion 631 and the second opposing portion 632, and the first gear cover 61 and the second gear cover 62 may contact each other at the third opposing portion 633. In addition, in the entirety from the first opposing portion 631 to the third opposing portion 633, the first gear cover 61 and the second gear cover 62 can be in contact or separated.

In addition, the gear cover 60 also has a recessed portion 64 disposed on the first gear cover 61. The recessed portion 64 is recessed to the right R at the end portion on the left L side of the first gear cover 61. By disposing the recessed portion 64, the first gear cover 61 can be made lighter. In addition, for example, even if a rib is disposed on the inner surface 521 of the second plate member 52 to which the first gear cover 61 is fixed, by embedding the rib into the recessed portion 64, interference of the rib can be suppressed and the first gear cover 61 can be mounted on the second plate member 52. In addition, when the first gear cover 61 is mounted on the second plate member 52, the first gear cover 61 can be positioned in the circumferential direction based on the first intermediate shaft J2 by embedding the rib into the recessed portion 64.

Preferably, the third opposing portion 633 is arranged at a position different from the recessed portion 64 in the circumferential direction based on the first intermediate shaft J2. For example, at least a portion of the third opposing portion 633 can be arranged on the other side of the circumferential direction based on the first intermediate shaft J2 than the recessed portion 64. In addition, the third opposing portion 633 can be arranged on the other side of the circumferential direction based on the first intermediate shaft J2 than the end portion on the right R side of the recessed portion 64. In this way, since the recessed portion 64 can be arranged away from the third opposing portion 633 in the circumferential direction, it is possible to prevent the strength of the first gear cover 61 from being reduced, compared with, for example, a case where at least a portion of the third opposing portion 633 is located at the same position as the recessed portion 64 in the circumferential direction based on the first intermediate shaft J2. However, the above example does not exclude a structure in which at least a portion of the third opposing portion 633 is arranged at the same position as the recessed portion 64 in the circumferential direction based on the first intermediate axis J2.

In addition, it is preferred that the opposing portion 63 is arranged to the right R of the recess 64. For example, in the present embodiment, all of the first opposing portion 631 to the third opposing portion 633 are arranged to the right R of the recess 64. In this way, the opposing portion 63 can be arranged away from the recess 64, thereby preventing the strength of the first gear cover 61 from being reduced due to the close arrangement of the two. However, the example does not exclude a structure in which a part of the opposing portion 63 is not arranged to the right R of the recess 64. For example, the first opposing portion 631 can also be arranged to the left L of the recess 64. Alternatively, the left L side of the first opposing portion 631 and the third opposing portion 633 can also be arranged to the left L of the recess 64.

In addition, the example of this embodiment does not exclude the structure in which the gear cover 60 does not have the recess 64.

In addition, it is preferred that the opposing portion 63 is arranged at a position to the right R of the first gear 43 and to the left L of the third gear 45 in the second engagement portion E2 where the third gear 45 and the second gear 44 engage. For example, the second opposing portion 63 is arranged to the right R of the first gear 43 and to the left L of the third gear 45. In this way, the third gear 45 can be surrounded by the second gear cover 62 without making it into a too complicated shape.

In addition, the gear cover 60 also has a cover 65. The cover 65 is arranged at a position L to the left of the third gear 45 and expands in a direction intersecting the axial direction. In the present embodiment, the cover 65 is formed integrally with the first gear cover 61. By configuring in this way, the number of parts of the gear cover 60 can be reduced compared with the structure in which the cover 65 is separated from the first gear cover 61. Therefore, the assembly workability of the gear cover 60 can be improved, and the manufacturing cost can be reduced. However, the example does not exclude the structure in which the cover 65 is separated from the first gear cover 61. For example, the cover 65 can be formed integrally with the second gear cover 62, or it can be formed separately from both the first gear cover 61 and the second gear cover 62.

<Second gear cover 62>

Next, the structure of the second gear cover 62 is described.

The second gear cover 62 has a side plate portion 621. In the side plate portion 621, a portion of the side plate portion 621 is arranged on the radially outer side of the drive gear 22 and the motor shaft 21 based on the center axis J1, surrounds the right R side portion of the radially outer end portion of the drive gear 22 (i.e., the portion where the gears are arranged) and the motor shaft 21, and extends along the circumferential direction based on the center axis J1. In addition, another portion of the side plate portion 621 is arranged on the radially outer side of the first gear 43 based on the first intermediate shaft J2, surrounds the right R side portion of the radially outer end portion of the first gear 43 (i.e., the portion where the gears are arranged), and extends along the circumferential direction based on the first intermediate shaft J2.

In addition, the second gear cover 62 also has a wall portion 622. The wall portion 622 surrounds the third gear 45 when viewed from the axial direction, and extends in the circumferential direction based on the second intermediate axis J3. Specifically, the wall portion 622 is arranged radially outward of the third gear 45 based on the center axis J1.

In addition, the second gear cover 62 also has an opening portion 623. The opening portion 623 penetrates the wall portion 622 in the radial direction based on the second intermediate shaft J3. The opening portion 623 is opposite to the housing 50 in the radial direction based on the second intermediate shaft J3, and more specifically, is opposite to the second cylinder portion 54 in the radial direction. By having the opening portion 623, the second gear cover 62 can be made lighter.

The wall portion 622 is adjacent to both sides of the opening portion 623 in the circumferential direction based on the second intermediate axis J3. Hereinafter, the end of the wall portion 622 that is arranged on the front side of the rotation direction Rt of the third gear 45 relative to the opening portion 623 and adjacent to the opening portion 623 among the circumferential ends of the wall portion 622 is referred to as the front side end portion 6241. The wall portion 622 has the front side end portion 6241. In addition, the end that is arranged on the rear side of the rotation direction Rt of the third gear 45 relative to the opening portion 623 and adjacent to the opening portion 623 is referred to as the rear side end portion 6251. The wall portion 622 also has a rear side end portion 6251.

FIG. 12 is an enlarged cross-sectional view of the opening 623 of the gear cover 60. FIG. 12 shows the opening 623 from the left L to the right R. As shown in FIG. 12, the front side end portion 6241 is in contact with the housing 50, and more specifically, is in contact with the inner surface of the second cylinder portion 54.

By configuring in this way, the third gear 45 and the gear cover 60 can be arranged close to the second cylinder portion 54 of the housing 50 according to the thickness of the wall portion 622 of the gear cover 60. Thus, the housing 50 can be miniaturized, that is, the drive device 10 can be miniaturized.

In addition, in the gear part 40, the lubricant is interposed between the gears. In addition, in the lubrication of the gears, a lubricant with high viscosity, i.e., a lubricant in the form of a so-called grease, is used. The gear cover 60 has an opening 623, and the second cylinder 54 of the housing 50 is arranged on the outer side of the opening 623, thereby, the lubricant for lubricating the third gear 45 moves in the part of the housing 50 close to the second cylinder 54, and the temperature rise of the lubricant can be suppressed. Thus, the reduction of the lubrication ability of the lubricant can be suppressed.

In addition, a grease-like lubricant is attached to the outer peripheral surface of the third gear 45 to suppress friction and wear between the gears. On the other hand, a grease-like lubricant is easy to form a mass. When the lubricant forms a certain degree of mass, it is easy to splash radially outward of the third gear 45 due to centrifugal force. For example, since the third gear 45 rotates, the lubricant may splash radially outward in the direction of rotation Rt. At this time, due to the centrifugal force generated by the rotation of the third gear 45, the lubricant may splash from the opening 623 to the radially outer side based on the second intermediate shaft J3, but the splashing lubricant can be more reliably received by the front side end portion in contact with the second cylinder portion 54 of the housing 50. Therefore, the gear cover 60 can be miniaturized, and the lubricant can be prevented from penetrating between the gear cover 60 and the second cylinder portion 54 of the housing 50.

Preferably, the front side end portion 6241 of the wall portion 622 has a front side elastic portion 6242. When viewed from the axial direction, the front side elastic portion 6242 extends from the rear side (i.e., the side of the opening portion 623) in the rotation direction Rt of the wall portion 622 arranged in front of the opening portion 623 in the rotation direction Rt. The front side elastic portion 6242 can be elastically deformed to contact the second tube portion 54 of the housing 50. By configuring in this way, the front side end portion 6241 can contact the second tube portion 54 more reliably. Therefore, the front side end portion 6241 can more reliably receive the lubricating material that splashes to the radially outer side based on the second intermediate shaft J3 due to the centrifugal force generated by the rotation of the third gear 45. As a result, it is more difficult for the lubricating material to penetrate between the gear cover 60 and the second cylindrical portion 54 of the housing 50.

More preferably, the front side elastic portion 6242 extends radially outward with the second intermediate shaft J3 as the reference as it moves toward the rear of the rotation direction Rt of the third gear 45. With such a configuration, when the lubricating material scattered to the second cylinder portion 54 side of the housing 50 moves due to the rotation of the third gear 45, the lubricating material can be picked up by the front side elastic portion 6242. However, the example does not exclude a structure in which the front side elastic portion 6242 does not extend radially outward as it moves toward the rear of the rotation direction Rt.

In addition, the above example does not exclude a structure in which the front side end portion 6241 does not have a front side elastic portion 6242 capable of elastic deformation. For example, the front side end portion 6241 may also directly contact the inner surface of the second cylinder portion 54 of the housing 50. Moreover, the above example does not exclude a structure in which the front side end portion 6241 does not contact the housing 50 (especially the inner surface of the second cylinder portion 54).

Preferably, as shown in FIG. 12 , the rear side end portion 6251 contacts the housing 50, more specifically, contacts the inner surface of the second cylinder portion 54. By configuring in this way, it is possible to suppress the lubricating material between the gears of the gear portion 40 from penetrating into the space between the gear cover 60 and the housing 50.

More preferably, the rear side end portion 6251 of the wall portion 622 has a rear side elastic portion 6252. When viewed axially, the rear side elastic portion 6252 extends from the front side (i.e., the side of the opening portion 623) in the rotation direction Rt of the wall portion 622 arranged behind the opening portion 623 in the rotation direction Rt. The rear side elastic portion 6252 can be elastically deformed and contact the second cylinder portion 54 of the housing 50. By configuring in this way, the infiltration of the lubricating material between the gear cover 60 and the housing 50 can be further suppressed.

However, the above example does not exclude a structure in which the rear side end portion 6251 does not have a rear side elastic portion 6252 capable of elastic deformation. For example, the rear side end portion 6251 may also directly contact the inner surface of the second cylinder portion 54 of the housing 50. Moreover, the above example does not exclude a structure in which the rear side end portion 6251 does not contact the housing 50 (especially the inner surface of the second cylinder portion 54).

In addition, as shown in FIG. 12 , a rib 6221 is formed at the rear side end portion 6251 of the wall portion 622. That is, the wall portion 622 has the rib 6221.

The rib 6221 protrudes from the inner surface of the wall portion 622 toward the third gear 45. For example, in the radial direction based on the second intermediate shaft J3, the radial inner side surface of the wall portion 622 is opposite to the radial outer side surface of the third gear 45. The rib 6221 protrudes from the radial inner side surface of the wall portion 622 to the radial inner side, and is opposite to the radial outer end of the third gear 45 with a gap therebetween.

By configuring in this way, the lubricant attached to the radial outer surface (i.e., the tooth surface) of the third gear 45 based on the second intermediate shaft J3 can be thinly spread and spread along the radial outer surface of the third gear 45. Thus, the lubricant can be prevented from agglomerating and from scattering radially outward. In addition, the lubricant can be stably attached to the third gear 45, and the lubrication effect of the third gear 45 can be improved.

In addition, by configuring the rib 6221 at the rear side end 6251, it is possible to prevent the lubricant from scattering from the opening 623 to the outside, and it is possible to prevent the lubricant from penetrating between the gear cover 60 and the housing 50.

In addition, as shown in FIG. 12 , the opposing surface of the rib 6221 that is opposed to the third gear 45 is a curved surface that protrudes toward the third gear 45. With this configuration, when the third gear 45 contacts the rib 6221 due to vibration or the like, since the teeth of the third gear 45 contact the curved surface, both the third gear 45 and the rib 6221 are not easily damaged. Thus, the drive device 10 can operate stably for a long time.

In addition, the present invention is not limited to the above example, and rib 6221 may also be omitted.

<Others>

The various technical features disclosed in this specification can be modified in various ways without departing from the main purpose of its technical creativity. In addition, the multiple implementation methods and variants shown in this specification can be combined and implemented within the possible scope.

The present invention can be applied to electric vehicles that obtain power from electricity, such as electric power-assisted bicycles, electric scooters, and electric wheelchairs.

21: Motor shaft

22: Drive gear

40: Gear unit

41: First gear shaft

43: First gear

44: Second gear

45: Third gear

53: First barrel

56: Support components

60: Gear cover

61: First gear cover

62: Second gear cover

63: Opposing part

64: Concave part

65: Cover

105a: Crankshaft

411: First bearing part

621: Side panel

622: Wall

623: Opening

631: First opposing part

632: Second opposing part

633: Third opposing part

6241:Front side end

6242: Front side elastic part

6251: Rear side end

6252: Rear side elastic part

E1: The first part of the fusion

E2: The second part of the fusion

J1: Center axis

J2: First intermediate shaft

J3: Second intermediate shaft

L: Left

R: Right

Claims (13)

A drive device has an axial direction on one side and an axial direction on the other side. The drive device is characterized in that it includes: a motor; an output part that outputs torque to the outside; and a gear part that transmits the torque of the motor to the output part. The motor includes: a shaft extending axially along a central axis; and a drive gear that can rotate around the central axis together with the shaft. The gear part includes: a first gear that engages with the drive gear; and a gear cover. The gear cover surrounds the drive gear and at least a portion of the first gear when viewed from the axial direction, and the gear cover includes: a first gear cover; a second gear cover arranged axially opposite to the first gear cover; and an opposing portion, wherein the end of the first gear cover on the other side in the axial direction is axially opposite to the end of the second gear cover on one side in the axial direction, and the first gear cover has a first gear cover side plate portion, and the first gear cover side plate portion is arranged to: The first gear cover side plate portion surrounds the drive gear and a portion of the first gear when viewed in the radial direction. The second gear cover has a second gear cover side plate portion, and the second gear cover side plate portion is configured to have a gap with the radial outer end of the drive gear and the first gear in the radial direction. When viewed in the radial direction, the second gear cover side plate portion surrounds the drive gear and a portion of the first gear. The opposing portion has a first opposing portion, the first opposing portion is opposite to the other axial end of the first gear cover side plate portion and the one axial end of the second gear cover side plate portion, the first opposing portion is opposed to the first engagement portion of the first gear and the drive gear in a direction perpendicular to the axial direction with a gap, and the first opposing portion is located between the one axial end and the other axial end of the first engagement portion in the axial direction. A drive device as described in claim 1, wherein the first gear cover and the second gear cover are axially opposed to each other with a gap therebetween. A drive device as described in claim 1, wherein at least a portion of the first gear cover is in axial contact with the second gear cover. A drive device as described in any one of claims 1 to 3, wherein the opposing portion further comprises: a second opposing portion, in which the end of the first gear cover on the other axial side of the first opposing portion is axially opposed to the end of the second gear cover on one axial side; a third opposing portion, in which the third opposing portion connects one circumferential end of the first opposing portion and the other circumferential end of the second opposing portion, and in which the first gear cover and the second gear cover are circumferentially opposed with a gap therebetween. The drive device as described in any one of claims 1 to 3, wherein the opposing portion further comprises: a second opposing portion, in which the end of the first gear cover in the other axial direction is axially opposed to the end of the second gear cover in the one axial direction on the other axial side of the first opposing portion; and a third opposing portion, in which the third opposing portion connects the circumferential end of the first opposing portion and the circumferential end of the second opposing portion, and in which at least a portion of the first gear cover is in contact with the second gear cover. A drive device as described in claim 4, wherein the gear cover has a recessed portion at one axial end of the first gear cover that is recessed toward the other axial end. A drive device as described in claim 6, wherein the third opposing portion is arranged at a position different from the recess in the circumferential direction. A drive device as described in claim 6, wherein the opposing portion is arranged axially closer to the other side than the recess. A drive device as described in any one of claims 1 to 3, wherein the gear portion further includes: a second gear, arranged on the other axial side of the first gear and capable of rotating together with the first gear; and a third gear, meshing with the second gear, The second gear cover also surrounds the third gear when viewed axially, and in the second meshing portion where the third gear meshes with the second gear, the opposing portion is arranged closer to the other axial side than the first gear and closer to one axial side than the third gear. The drive device as described in claim 9 further comprises: a housing, the housing having an internal space, the motor, a part of the output portion and the gear portion being accommodated in the internal space; the second gear cover comprising: a wall portion, surrounding the third gear when viewed from the axial direction; and an opening portion, radially penetrating the wall portion, the opening portion being radially opposite to the housing, the wall portion having: a front side end portion, arranged in front of the rotation direction of the third gear relative to the opening portion, the front side end portion being in contact with the housing. The drive device as described in claim 10, wherein the wall portion further includes: a rear side end portion, which is arranged behind the rotation direction of the third gear relative to the opening portion, and the rear side end portion is in contact with the housing. The drive device as described in claim 9, wherein the gear cover further includes: a cover portion, the cover portion is arranged at a position closer to the axial direction than the third gear and expands in a direction intersecting the axial direction, and the cover portion is integral with the first gear cover. An electric vehicle, characterized by comprising: a driving device as described in any one of claims 1 to 12.