JP7567385B2 - Reduction gear and brake device - Google Patents

Description

Embodiments of the present invention relate to a reduction gear and a brake device.

Conventionally, there is known a reduction gear that can cushion the rotational force of the fixed gear by holding the protruding portion of the fixed gear in the circumferential direction with a cushioning material (for example, Patent Document 1).

JP 2004-129374 A

However, with conventional configurations, it can be difficult to ensure that parts in the reduction gear device are securely engaged during manufacturing.

Therefore, the present invention has been made in consideration of the above, and provides a reduction gear and a brake device that enable reliable engagement of parts during manufacturing.

As an example, a reduction gear transmission according to an embodiment of the present invention includes a housing having an inner circumferential surface of a hole that is open in a first direction, a wall portion that protrudes from the inner circumferential surface at a position spaced from an end of the hole in the first direction in a second direction opposite to the first direction, and a first end in a first circumferential direction of the inner circumferential surface; a gear assembly that is accommodated in the hole and has an outer circumferential surface facing the inner circumferential surface, a plurality of gears that are provided inside the outer circumferential surface and mesh with each other, and a second end in a second circumferential direction opposite to the first circumferential direction, spaced from the first end in the first circumferential direction, and a gear assembly that is interposed between the first end and the second end and that is interposed between the housing and the outer circumferential surface. The present invention includes a rotation prevention member having a base that limits the relative movement of the housing and the gear assembly in a direction in which the first end and the second end approach each other, and a second engagement portion that is provided at an end of the base in the first direction and at least partially faces a first engagement portion provided on one of the housing and the gear assembly to limit the movement of the base in the first direction relative to the housing and the gear assembly, the rotation prevention member having two protrusions extending in the first direction from an end of the base in the first direction, and the second engagement portion is located between the two protrusions. Thus, as an example, it is possible to visually check whether the first engagement portion and the second engagement portion are engaged through an end of the hole in the first direction that is opened. Therefore, the first engagement portion and the second engagement portion can be more reliably engaged during manufacturing, and the production efficiency of the reduction gear can be improved. Also, as an example, when the rotation prevention member is inserted into the space between the first end and the second end, the protrusions can bear the load of the insertion operation. Therefore, the load is prevented from acting on the second engagement portion. In addition, as one example, the two protruding portions surround the second engagement portion, and the load during the insertion operation is prevented from acting on the second engagement portion.
Also, as one example, a reduction gear transmission according to another embodiment of the present invention includes a housing having an inner circumferential surface of a hole that is open in a first direction, a wall portion that protrudes from the inner circumferential surface at a position spaced from an end of the hole in the first direction in a second direction opposite to the first direction, and a first end in a first circumferential direction of the inner circumferential surface; a gear assembly that is accommodated in the hole and has an outer circumferential surface facing the inner circumferential surface, a plurality of gears that are provided inside the outer circumferential surface and mesh with each other, and a second end in a second circumferential direction opposite to the first circumferential direction and spaced from the first end in the first circumferential direction; and a bearing that is interposed between the first end and the second end to restrict relative movement of the housing and the gear assembly in a direction in which the first end and the second end approach each other. and a rotation prevention member having a base and a second engagement portion provided at an end of the base in the first direction and facing at least partially with a first engagement portion provided on one of the housing and the gear assembly to limit the movement of the base in the first direction relative to the housing and the gear assembly, the rotation prevention member having a protrusion extending in the first direction from an end of the base in the first direction, the protrusion being spaced from the second engagement portion in the first circumferential direction or the second circumferential direction, the distance between the protrusion and the second engagement portion in the first circumferential direction being shorter than the minimum length of the protrusion in the first circumferential direction and shorter than the minimum length of the second engagement portion in the first circumferential direction. Thus, as an example, it is possible to visually check whether the first engagement portion and the second engagement portion are engaged through the end of the hole in the opened first direction. Therefore, the first engagement portion and the second engagement portion can be more reliably engaged during manufacturing, and the production efficiency of the reduction gear can be improved. As another example, when the anti-rotation member is inserted into the space between the first end and the second end, the protrusion can bear the load of the insertion operation, thereby preventing the load from acting on the second engagement portion. As another example, the protrusion or the second engagement portion of one anti-rotation member is prevented from entering the space between the protrusion and the second engagement portion of another anti-rotation member.
In the reduction gear transmission, as one example, the anti-rotation member has two protruding portions extending in the first direction from an end of the base in the first direction, and the second engagement portion is located between the two protruding portions. Thus, as one example, the two protruding portions surround the second engagement portion, and the load of the insertion operation is prevented from acting on the second engagement portion.

In the above reduction gear device, as one example, the second engagement portion has a snap-fit arm extending from an end of the base in the first direction, and an engagement surface provided on the snap-fit arm and facing the first engagement portion to restrict the movement of the base in the first direction relative to the housing and the gear assembly, and the snap-fit arm is capable of moving the engagement surface to a position that allows the base to move in the first direction relative to the housing and the gear assembly by elastically deforming. Thus, as one example, the shapes of the housing and the gear assembly are prevented from becoming complicated, and the production efficiency of the reduction gear device can be improved.

In the above reduction gear device, as one example, the engagement surface is provided on the end of the snap-fit arm in the first direction. Therefore, as one example, it is easily visible whether the first engagement portion and the second engagement portion are engaged. Therefore, the first engagement portion and the second engagement portion can be more reliably engaged during manufacturing, and the production efficiency of the reduction gear device can be improved.

In the above reduction gear device, as one example, the color of the first engagement portion is different from the color of the second engagement portion. Therefore, as one example, it is easily visible whether the first engagement portion and the second engagement portion are engaged. Therefore, the first engagement portion and the second engagement portion can be more reliably engaged during manufacturing, and the production efficiency of the reduction gear device can be improved.

As an example, a brake device according to an embodiment of the present invention includes the above-mentioned reduction gear in which the multiple gears are driven by a motor, a rotary-linear motion conversion mechanism having a rotating member rotated by the multiple gears and a linear motion member that moves linearly in response to the rotation of the rotating member, and a braking member that is pressed against the brake rotor in response to the linear motion of the linear motion member. Therefore, as an example, the first engagement portion and the second engagement portion can be more reliably engaged during manufacturing, and the production efficiency of the brake device can be improved.

FIG. 1 is a perspective view showing a portion of a brake device according to an embodiment. FIG. 2 is a plan view showing a part of the brake device of the above embodiment. FIG. 3 is a cross-sectional view showing the brake device of the above embodiment taken along line F3-F3 in FIG. FIG. 4 is a cross-sectional view showing the brake caliper of the above embodiment. FIG. 5 is a cross-sectional view that typically shows the gear assembly and the casing of the above embodiment. FIG. 6 is a perspective view showing the anti-rotation member of the embodiment. FIG. 7 is a cross-sectional view showing a part of the brake device of the above embodiment. FIG. 8 is a cross-sectional view showing a schematic view of the housing and gear assembly during manufacture of the above embodiment. FIG. 9 is a cross-sectional view that shows a schematic view of the housing, the gear assembly, and the anti-rotation member during the manufacturing process of the above embodiment. FIG. 10 is a plan view of the brake device of the above embodiment as viewed in a second direction. FIG. 11 is a cross-sectional view showing a part of a brake device according to a first modified example of the above embodiment. FIG. 12 is a cross-sectional view showing a part of a brake device according to a second modification of the above embodiment.

Below, one embodiment of the present invention will be described with reference to Figs. 1 to 10. Note that in this specification, components according to the embodiment and descriptions of the components may be described in multiple ways. The components and their descriptions are merely examples and are not limited by the expressions in this specification. The components may also be identified by names different from those in this specification. The components may also be described by expressions different from those in this specification.

Figure 1 is a perspective view showing a portion of a brake device 10 according to one embodiment. Figure 2 is a plan view showing a portion of the brake device 10 of this embodiment. Figure 3 is a cross-sectional view showing the brake device 10 of this embodiment along line F3-F3 in Figure 2.

The brake device 10 is capable of operating as a hydraulic brake and an electric brake, and is mounted on a vehicle 1 such as an automobile. Note that the brake device 10 is not limited to this example. As shown in Figs. 1 and 3, the brake device 10 has a housing 11, a motor 12, a rotation transmission mechanism 13, a rotary-to-linear motion conversion mechanism 14, and a brake caliper 15. The rotary-to-linear motion conversion mechanism 14 is built into, for example, the brake caliper 15. Note that the rotary-to-linear motion conversion mechanism 14 is not limited to this example.

The brake caliper 15 is included in the brake device 10 as a hydraulic brake. The motor 12, the rotation transmission mechanism 13, the rotary-linear conversion mechanism 14, and the brake caliper 15 are included in the brake device 10 as an electric brake. The electric brake is a so-called electric parking brake. That is, the brake device 10 is configured so that the braking state by the electric brake function is maintained when parking. The electric brake may be activated when driving or when temporarily stopped.

The housing 11 houses the motor 12 and the rotation transmission mechanism 13. As shown in FIG. 3, the housing 11 has a casing 21 and an outer cover 22. The casing 21 and the outer cover 22 are made of, for example, synthetic resin. Note that the casing 21 and the outer cover 22 may be made of other materials.

As shown in FIG. 1, the casing 21 is provided with a first recess 25 and a second recess 26. As shown in FIG. 3, the casing 21 is provided with a third recess 27. The second recess 26 is an example of a hole.

As shown in FIG. 1, the first recess 25 and the second recess 26 are each a substantially circular recess recessed from the end surface 21a of the casing 21 in the first direction D1. In other words, the first recess 25 and the second recess 26 are recesses that are open in the first direction D1. The first recess 25 and the second recess 26 may be covered by other components.

As shown in FIG. 3, the third recess 27 is a recess recessed from the end surface 21b of the casing 21 in the second direction D2. In other words, the third recess 27 is a recess that is open in the second direction D2. The third recess 27 may be covered by another component. The second direction D2 is the opposite direction to the first direction D1.

As shown in FIG. 1, the first recess 25 is a substantially cylindrical space extending along a first central axis Ax1. The first central axis Ax1 is located approximately at the center of the first recess 25 and is a virtual central axis (axial center) extending in a first direction D1 and a second direction D2.

The second recess 26 is a substantially cylindrical space extending along the second central axis Ax2. The second central axis Ax2 is located approximately at the center of the second recess 26 and is a virtual central axis (axial center) extending in the first direction D1 and the second direction D2.

In the following description, the direction along the second central axis Ax2 is defined as the axial direction, the direction perpendicular to the second central axis Ax2 is defined as the radial direction, and the direction rotating around the second central axis Ax2 is defined as the circumferential direction. The axial direction includes the first direction D1 and the second direction D2.

As shown in FIG. 2, the circumferential direction includes a first circumferential direction Da1 and a second circumferential direction Da2. The first circumferential direction Da1 is one direction of rotation around the second central axis Ax2. The second circumferential direction Da2 is the opposite direction of the first circumferential direction Da1.

The first central axis Ax1 and the second central axis Ax2 extend substantially parallel to each other. The first central axis Ax1 is radially spaced apart from the second central axis Ax2. The first recess 25 is radially spaced apart from the second recess 26. In other words, the first recess 25 and the second recess 26 are separated from each other.

At least a portion of the motor 12 is housed in the first recess 25. The drive shaft 12a of the motor 12 passes through a through hole that opens to the bottom of the first recess 25 and is partially disposed in the third recess 27. The drive shaft 12a extends along the first central axis Ax1. When the motor 12 is driven, the drive shaft 12a rotates around the first central axis Ax1. The drive shaft 12a may also be referred to as a shaft or a rotor.

The rotation transmission mechanism 13 has a pinion 31, an intermediate gear 32, and a planetary gear mechanism 33. The pinion 31 is located in the third recess 27 and is fixed to the drive shaft 12a of the motor 12. The intermediate gear 32 is housed in the third recess 27 so as to be rotatable around a central axis that is substantially parallel to the first central axis Ax1 and the second central axis Ax2. The intermediate gear 32 meshes with the pinion 31.

As shown in FIG. 3, the planetary gear mechanism 33 has a sun gear 35, a planetary carrier 36, and a ring gear 37. The sun gear 35 is an example of a gear. In this embodiment, the planetary gear mechanism 33 is a planetary gear mechanism having one set of the sun gear 35, the planetary carrier 36, and the ring gear 37, but it may be a planetary gear mechanism having multiple sets of the sun gear 35, the planetary carrier 36, and the ring gear 37.

The sun gear 35 and the planetary carrier 36 are rotatable around the second central axis Ax2 relative to the casing 21. The ring gear 37 is formed in a generally cylindrical shape extending in the circumferential direction of the second central axis Ax2 and is substantially fixed to the casing 21. The ring gear 37 may be slightly movable relative to the casing 21.

A portion of the sun gear 35 is housed in the third recess 27. The third recess 27 is covered by the outer cover 22 attached to the casing 21. The sun gear 35 is supported by the outer cover 22 so as to be rotatable around the second central axis Ax2.

The sun gear 35 has an input gear 35a and an output gear 35b. The input gear 35a and the output gear 35b can rotate together around the second central axis Ax2.

The input gear 35a is located in the third recess 27 and meshes with the intermediate gear 32. The number of teeth of the gear in the intermediate gear 32 that meshes with the input gear 35a is smaller than the number of teeth of the gear that meshes with the pinion 31. Therefore, the intermediate gear 32 reduces the rotation of the motor 12 and transmits it to the sun gear 35. The output gear 35b is located in the second recess 26 and drives the planetary carrier 36.

The planetary carrier 36 is housed in the second recess 26. The planetary carrier 36 has a carrier base 36a, multiple pinion shafts 36b, multiple pinion gears 36c, and an output shaft 36d. The pinion gear 36c is an example of a gear.

The carrier base 36a, the pinion shaft 36b, and the output shaft 36d are made of, for example, synthetic resin. The pinion gear 36c is made of, for example, metal. Note that the material of the planetary carrier 36 is not limited to this example.

The carrier base 36a can rotate around the second central axis Ax2. The carrier base 36a and the sun gear 35 can rotate relatively around the second central axis Ax2.

The multiple pinion shafts 36b protrude from the carrier base 36a in the second direction D2. The multiple pinion shafts 36b are arranged radially spaced apart from the second central axis Ax2 and spaced apart from each other circumferentially. The pinion shafts 36b are formed integrally with the carrier base 36a. Note that the pinion shafts 36b are not limited to this example.

The pinion gear 36c is supported by the corresponding pinion shaft 36b so as to be rotatable around the central axis of the pinion gear 36c. The central axis of the pinion shaft 36b extends substantially parallel to the second central axis Ax2.

The output shaft 36d protrudes from the carrier base 36a in the first direction D1 along the second central axis Ax2. The output shaft 36d can rotate around the second central axis Ax2 together with the carrier base 36a.

The ring gear 37 is made of, for example, synthetic resin. However, the material of the ring gear 37 is not limited to this example. The ring gear 37 has an outer gear 37a. The outer gear 37a is provided on the inner peripheral surface of the ring gear 37. The pinion gear 36c meshes with the output gear 35b of the sun gear 35 and also meshes with the outer gear 37a of the ring gear 37.

When the motor 12 rotates the drive shaft 12a and the pinion 31, the intermediate gear 32 transmits the rotation of the pinion 31 to the sun gear 35. When the sun gear 35 rotates around the second central axis Ax2, the pinion gear 36c rotates around the central axis of the pinion shaft 36b and revolves around the second central axis Ax2. This causes the carrier base 36a and the output shaft 36d to rotate around the second central axis Ax2. Therefore, the planetary gear mechanism 33 decelerates the rotation of the intermediate gear 32 and outputs it from the output shaft 36d.

The brake device 10 has a reduction gear 10a that reduces the rotation of the drive shaft 12a of the motor 12 and outputs it from the output shaft 36d. The housing 11 and the rotation transmission mechanism 13 are included in the reduction gear 10a.

Figure 4 is a cross-sectional view showing the brake caliper 15 of this embodiment. The brake caliper 15 is attached to the housing 11. As shown in Figure 4, the brake caliper 15 has a body 41, a piston 42, and a seal 43.

A cylinder 44 is provided in the body 41. The cylinder 44 is a recess that extends along the second central axis Ax2 and is open in the first direction D1. The piston 42 is housed in the cylinder 44 so as to be movable in the axial direction.

In the cylinder 44, a hydraulic chamber 46 is provided between the piston 42 and the bottom 44a of the cylinder 44 in the second direction D2. When the hydraulic pressure in the hydraulic chamber 46 increases, the piston 42 is pushed in the first direction D1.

The piston 42 has an outer peripheral surface 42a and an abutment surface 42b. The outer peripheral surface 42a is formed in a generally cylindrical shape extending along the second central axis Ax2. The abutment surface 42b is the end surface of the piston 42 in the first direction D1.

The outer peripheral surface 42a faces the inner peripheral surface 44b of the cylinder 44 via a small gap. The outer peripheral surface 42a slides against the inner peripheral surface 44b in a lubricated state where hydraulic fluid is present in the gap. A seal 43 is interposed between the body 41 and the piston 42 to prevent hydraulic fluid from leaking from the hydraulic chamber 46 through the gap.

The piston 42 is provided with a recess 42c and multiple grooves 42d. The recess 42c is a substantially circular recess that opens in the second direction D2. The recess 42c is connected to the hydraulic chamber 46 of the cylinder 44. The grooves 42d are recessed radially outward from the inner peripheral surface of the recess 42c and extend in the axial direction. The multiple grooves 42d are arranged at intervals in the circumferential direction.

The brake device 10 further includes a brake pad 51 assembled to the brake caliper 15 and a disc rotor 52 attached to a wheel of the vehicle 1. The brake pad 51 is an example of a braking member. The disc rotor 52 is an example of a brake rotor. The brake pad 51 may be included in the brake caliper 15.

The brake pad 51 has a back plate 55 and a lining 56. The back plate 55 abuts against the abutment surface 42b of the piston 42. The piston 42, pressed by the hydraulic pressure in the hydraulic chamber 46, pushes the back plate 55 in the first direction D1, thereby pressing the lining 56 against the disc rotor 52. This brakes the wheels of the vehicle 1, and a braking state is obtained by the hydraulic brake.

The seal 43 has a retract function that retracts the piston 42 in the second direction D2 by elastic force as the hydraulic pressure in the hydraulic chamber 46 decreases, and separates the contact surface 42b of the piston 42 from the brake pad 51. In other words, when the pressure of the piston 42 against the back plate 55 is released as the hydraulic pressure in the hydraulic chamber 46 decreases, the piston 42 releases the pressure of the lining 56 against the disc rotor 52, thereby obtaining a brake release state by the hydraulic brake. As described above, the brake caliper 15 can operate as a hydraulic brake.

As described above, the rotary-linear motion conversion mechanism 14 is provided in the brake caliper 15. The rotary-linear motion conversion mechanism 14 has a rotating member 61, a thrust bearing 62, and a linear motion member 63.

The rotating member 61 is supported by the body 41 of the brake caliper 15 so as to be rotatable about the second central axis Ax2. The rotating member 61 has a coupling portion 61a, a flange 61b, and a shaft 61c.

The coupling portion 61a passes through an insertion hole 44c that opens in the bottom portion 44a of the cylinder 44 and is coupled to the output shaft 36d of the planetary gear mechanism 33. The flange 61b and the shaft 61c are disposed in the cylinder 44. The flange 61b is located between the coupling portion 61a and the shaft 61c, and protrudes radially outward from the outer circumferential surfaces of the coupling portion 61a and the shaft 61c. The shaft 61c extends from the flange 61b in the second direction D2 along the second central axis Ax2. A male thread 61d is provided on the outer circumferential surface of the shaft 61c.

The thrust bearing 62 is interposed between the bottom 44a of the cylinder 44 and the flange 61b of the rotating member 61. As a result, the flange 61b is supported by the bottom 44a of the cylinder 44 via the thrust bearing 62 so as to be rotatable around the second central axis Ax2.

The linear motion member 63 has a tubular portion 63a and multiple protrusions 63b. The tubular portion 63a is formed in a substantially cylindrical shape extending along the second central axis Ax2. A female thread 63c is provided on the inner surface of the tubular portion 63a. The female thread 63c meshes with the male thread 61d of the rotating member 61. The protrusions 63b protrude radially outward from the outer circumferential surface of the tubular portion 63a. The multiple protrusions 63b are arranged at intervals in the circumferential direction.

At least a portion of the rotary-linear conversion mechanism 14 is accommodated in the recess 42c of the piston 42. The cylindrical portion 63a of the linear motion member 63 is accommodated in the recess 42c so as to be movable in the axial direction. The protrusion 63b is accommodated in the groove 42d so as to be movable in the axial direction. The side surface of the groove 42d abuts against the protrusion 63b, thereby restricting the rotation of the linear motion member 63 around the second central axis Ax2. In this embodiment, the rotation of the piston 42 around the second central axis Ax2 is restricted by friction between the piston 42 and the seal 43 and the brake pad 51.

When the rotating member 61 rotates around the second central axis Ax2, the linear motion member 63 moves axially (linear motion) in response to the rotation of the rotating member 61. For example, when the motor 12 rotates the drive shaft 12a in one direction, the rotation transmission mechanism 13 transmits the rotation from the output shaft 36d to the rotating member 61. That is, the rotating member 61 is rotated by the pinion 31 of the rotation transmission mechanism 13 driven by the motor 12, the intermediate gear 32, and the sun gear 35 and pinion gear 36c of the planetary gear mechanism 33. As a result, the linear motion member 63 moves in the second direction D2, pushing the piston 42 in the second direction D2.

The piston 42 pushed in the second direction D2 presses the brake pad 51 against the disc rotor 52. That is, the brake pad 51 is pressed against the disc rotor 52 in response to the linear motion of the linear motion member 63. This results in a braking state due to the electric brake function, in which the wheels of the vehicle 1 that rotate integrally with the disc rotor 52 are braked.

On the other hand, when the motor 12 rotates the drive shaft 12a in the other direction, the rotation transmission mechanism 13 transmits the rotation from the output shaft 36d to the rotating member 61. As a result, the linear motion member 63 moves in the first direction D1, and the piston 42 moves in the first direction D1.

When the piston 42 moves, the piston 42 releases its pressure on the brake pad 51, and the piston 42 releases the brake pad 51 from pressing against the disc rotor 52. This results in a release state of braking by the electric brake function. As described above, the motor 12, the rotation transmission mechanism 13, the rotary-to-linear motion conversion mechanism 14, and the brake caliper 15 can operate as an electric brake.

The brake device 10 described above has a gear assembly 70 shown in FIG. 3. The gear assembly 70 has the planetary carrier 36 and the ring gear 37 of the planetary gear mechanism 33. The gear assembly 70 may have other gears. The gear assembly 70 is housed in the second recess 26 of the casing 21.

The gear assembly 70 and the casing 21 are described in detail below. The ring gear 37 of the gear assembly 70 has a peripheral wall 71 and a bottom wall 72. As described above, the ring gear 37 also has an outer gear 37a.

The peripheral wall 71 is formed in a generally cylindrical shape extending in the circumferential direction of the second central axis Ax2. The peripheral wall 71 has an outer peripheral surface 71a and an inner peripheral surface 71b. The outer peripheral surface 71a is a generally cylindrical surface facing radially outward. The inner peripheral surface 71b is located on the opposite side of the outer peripheral surface 71a and is a generally cylindrical surface facing radially inward. In other words, the inner peripheral surface 71b faces the second central axis Ax2.

The central axis of the outer peripheral surface 71a and the second central axis Ax2 are approximately the same. Therefore, the axial direction is the direction along the central axis of the outer peripheral surface 71a, i.e., the axial direction of the outer peripheral surface 71a. The radial direction is also the direction perpendicular to the central axis of the outer peripheral surface 71a, i.e., the radial direction of the outer peripheral surface 71a. The circumferential direction (first circumferential direction Da1 and second circumferential direction Da2) is the direction of rotation around the central axis of the outer peripheral surface 71a, i.e., the circumferential direction of the outer peripheral surface 71a.

An outer gear 37a is provided on the inner circumferential surface 71b of the peripheral wall 71. In addition, the output gear 35b of the sun gear 35 and the pinion gear 36c of the planetary carrier 36 are located inside the peripheral wall 71.

The outer peripheral surface 71a of the peripheral wall 71 is the outer peripheral surface of the gear assembly 70. The output gear 35b of the sun gear 35, the pinion gear 36c of the planetary carrier 36, and the outer gear 37a of the ring gear 37 are provided inside the outer peripheral surface 71a and mesh with each other.

The bottom wall 72 is a generally annular wall that protrudes from the end of the inner circumferential surface 71b of the peripheral wall 71 in the first direction D1. The bottom wall 72 supports the carrier base 36a of the planetary carrier 36 in the second direction D2. The output shaft 36d of the planetary carrier 36 passes through the inside of the bottom wall 72 and protrudes to the outside of the ring gear 37.

Figure 5 is a cross-sectional view showing a schematic of the gear assembly 70 and the casing 21 of this embodiment. Figure 5 shows the gear assembly 70 and the casing 21 by developing the circumferential direction into a plane. That is, the left direction in Figure 5 is the first circumferential direction Da1, and the right direction in Figure 5 is the second circumferential direction Da2.

As shown in FIG. 5, the ring gear 37 of the gear assembly 70 further includes a first slider 75, a second slider 76, and a first engagement portion 77. In this embodiment, the ring gear 37 includes a plurality of first sliders 75, a plurality of second sliders 76, and a first engagement portion 77 that are spaced apart from each other in the circumferential direction.

The first slider 75 protrudes radially outward from the outer circumferential surface 71a of the peripheral wall 71. In the axial direction, the end face 75a of the first slider 75 in the first direction D1 is disposed at approximately the same position as the end face 71c of the peripheral wall 71 in the first direction D1. Furthermore, in the axial direction, the end face 75b of the first slider 75 in the second direction D2 is disposed at approximately the same position as the end face 71d of the peripheral wall 71 in the second direction D2. In other words, the length of the peripheral wall 71 in the axial direction and the length of the first slider 75 in the axial direction are approximately equal. Note that the first slider 75 is not limited to this example.

The first slider 75 has side surfaces 75c and 75d. Side surface 75d is an example of a second end portion. Side surface 75c is an end portion of the first slider 75 in the first circumferential direction Da1 and faces the first circumferential direction Da1. Side surface 75d is located on the opposite side to side surface 75c. Side surface 75d is an end portion of the first slider 75 in the second circumferential direction Da2 and faces the second circumferential direction Da2.

At the position where the peripheral wall 71 is provided in the radial direction, the peripheral wall 71 extends endlessly. However, at the position where the first slider 75 is provided in the radial direction, the side surface 75c is one of the ends of the gear assembly 70 in the first circumferential direction Da1. Also, the side surface 75d is one of the ends of the gear assembly 70 in the second circumferential direction Da2.

The second slider 76 protrudes radially outward from the outer circumferential surface 71a of the peripheral wall 71. The second slider 76 is spaced apart in the circumferential direction from the first slider 75. The second slider 76 is closer to the end face 71d of the peripheral wall 71 in the second direction D2 than to the end face 71c of the peripheral wall 71 in the first direction D1. Note that the position of the second slider 76 in the axial direction is not limited to this example.

The first engagement portion 77 is located between the first slider 75 and the second slider 76 in the circumferential direction. In the axial direction, the first engagement portion 77 is closer to the end face 71c of the peripheral wall 71 in the first direction D1 than to the end face 71d of the peripheral wall 71 in the second direction D2. In this embodiment, the first engagement portion 77 is adjacent to the end face 71c.

In this embodiment, the first engagement portion 77 protrudes radially outward from the outer circumferential surface 71a of the peripheral wall 71. Note that the first engagement portion 77 is not limited to this example, and may be provided with a recess recessed radially inward from the outer circumferential surface 71a, for example.

The casing 21 further has an inner circumferential surface 81 and a wall portion 82 shown in FIG. 3, and a first stopper 83, a second stopper 84, and a retaining portion 85 shown in FIG. 5. The inner circumferential surface 81 in FIG. 3 is the inner circumferential surface of the second recess 26, and is a substantially cylindrical surface facing radially inward. In other words, the inner circumferential surface 81 faces the second central axis Ax2.

The central axis of the inner circumferential surface 81 and the second central axis Ax2 are approximately the same. Therefore, the axial direction is the direction along the central axis of the inner circumferential surface 81, i.e., the axial direction is also the direction perpendicular to the central axis of the inner circumferential surface 81, i.e., the radial direction is also the radial direction of the inner circumferential surface 81. The circumferential directions (first circumferential direction Da1 and second circumferential direction Da2) are the directions rotating around the central axis of the inner circumferential surface 81, i.e., the circumferential directions of the inner circumferential surface 81.

The wall portion 82 is a generally annular wall that protrudes from the inner circumferential surface 81 at a position spaced in the second direction D2 from the end 26a of the second recess 26 in the first direction D1. The end 26a of the second recess 26 opens into the end surface 21a of the casing 21.

The wall portion 82 separates the second recess 26 and the third recess 27. The wall portion 82 supports the input gear 35a of the sun gear 35 in the second direction D2. The output gear 35b of the sun gear 35 passes through the inside of the approximately annular wall portion 82 and protrudes into the second recess 26.

The wall portion 82 has a bottom surface 82a. The bottom surface 82a is the bottom of the second recess 26 and faces the first direction D1. The bottom surface 82a supports the pinion gear 36c of the planetary carrier 36 in the first direction D1.

When the gear assembly 70 is housed in the second recess 26, the outer peripheral surface 71a of the gear assembly 70 faces the inner peripheral surface 81. In addition, the end surface 71d of the gear assembly 70 faces the bottom surface 82a of the wall portion 82.

As shown in FIG. 5, the first stopper 83 protrudes radially inward from the inner circumferential surface 81 and extends in the axial direction. The first stopper 83 has a side surface 83a and an end portion 83b. The side surface 83a is an example of the first end portion.

The side surface 83a is an end of the first stopper 83 in the first circumferential direction Da1 and faces the first circumferential direction Da1. At the position where the first stopper 83 is provided in the radial direction, the side surface 83a is one of the ends of the casing 21 in the first circumferential direction Da1. The end surface 83b is the end of the first stopper 83 in the first direction D1.

The second stopper 84 is provided at a position spaced apart from the first stopper 83 in the first circumferential direction Da1. The second stopper 84 protrudes radially inward from the inner circumferential surface 81 and extends in the axial direction. The second stopper 84 has a side surface 84a. The side surface 84a is an end of the second stopper 84 in the second circumferential direction Da2 and faces the second circumferential direction Da2.

The retaining portion 85 protrudes radially inward from the inner circumferential surface 81. The retaining portion 85 is formed in a substantially L-shape and has a rail 85a and a stopper 85b. The rail 85a is provided at a position spaced apart from the wall portion 82 in the first direction D1 and extends in the circumferential direction. The stopper 85b extends in the second direction D2 from the end of the rail 85a in the first circumferential direction Da1. The stopper 85b may be connected to the wall portion 82.

The second slider 76 of the gear assembly 70 is located between the wall portion 82 and the rail 85a of the holding portion 85. The rail 85a of the holding portion 85 abuts against the second slider 76, thereby restricting the movement of the gear assembly 70 in the first direction D1 relative to the casing 21.

The end surface 71d of the peripheral wall 71 of the gear assembly 70 faces the bottom surface 82a of the wall portion 82. The bottom surface 82a of the wall portion 82 abuts against the end surface 71d of the peripheral wall 71, thereby restricting the gear assembly 70 from moving in the second direction D2 relative to the casing 21.

The first slider 75 of the gear assembly 70 is located between the first stopper 83 and the second stopper 84 in the circumferential direction. The side surface 75c of the first slider 75 faces the side surface 84a of the second stopper 84. The side surface 84a of the second stopper 84 abuts against the side surface 75c of the first slider 75, thereby restricting the movement of the gear assembly 70 in the first circumferential direction Da1 relative to the casing 21.

The side surface 75d of the first slider 75 of the gear assembly 70 is spaced from the side surface 83a of the first stopper 83 in the first circumferential direction Da1. Therefore, a space S is provided between the side surface 75d of the first slider 75 and the side surface 83a of the first stopper 83. In the radial direction, the space S is provided between the outer peripheral surface 71a of the gear assembly 70 and the inner peripheral surface 81 of the casing 21.

The brake device 10 further includes a rotation-stop member 90 that is inserted into the space S. The rotation-stop member 90 is made of, for example, a synthetic resin. The elastic modulus of the rotation-stop member 90 is equal to or less than the elastic modulus of the ring gear 37. Note that the rotation-stop member 90 is not limited to this example.

Figure 6 is a perspective view showing the anti-rotation member 90 of this embodiment. As shown in Figure 6, the anti-rotation member 90 has a base 91, a second engagement portion 92, and two protrusions 93. The base 91, the second engagement portion 92, and the protrusions 93 are integrally formed. Note that at least one of the base 91, the second engagement portion 92, and the protrusions 93 may be formed as a separate part from the other parts.

The base 91 is formed in a generally rectangular plate shape. The base 91 has ends 91a and 91b, side surfaces 91c and 91d, an inner surface 91e, and an outer surface 91f. Note that the base 91 is not limited to this example and may have other shapes.

As shown in FIG. 5, end 91a is the end of base 91 in first direction D1. End 91b is the end of base 91 in second direction D2. Side 91c is the end of base 91 in first circumferential direction Da1. Side 91d is the end of base 91 in second circumferential direction Da2. Inner surface 91e faces radially inward. Outer surface 91f faces radially outward.

The base 91 is interposed between the side surface 83a of the first stopper 83 and the side surface 75d of the first slider 75. The length of the base 91 in the circumferential direction is equal to or slightly shorter than the length of the space S in the circumferential direction. Therefore, the base 91 essentially fills the space S in the circumferential direction.

The side surface 91c faces the side surface 75d of the first slider 75. The side surface 91d faces the side surface 83a of the first stopper 83. With the side surface 91c abutting against the side surface 75d of the first slider 75 and the side surface 91d abutting against the side surface 83a of the first stopper 83, the base 91 restricts the movement of the gear assembly 70 in the second circumferential direction Da2 relative to the casing 21. In other words, the base 91 restricts the relative movement of the housing 11 and the gear assembly 70 in the direction in which the side surface 75d and the side surface 83a approach each other.

The end 91b faces the bottom surface 82a of the wall portion 82. The bottom surface 82a of the wall portion 82 abuts against the end 91b, thereby restricting the base 91 from moving in the second direction D2 relative to the housing 11 and the gear assembly 70.

As shown in FIG. 6, the inner surface 91e faces the outer peripheral surface 71a of the gear assembly 70. The outer surface 91f faces the inner peripheral surface 81 of the casing 21. The outer peripheral surface 71a and the inner peripheral surface 81 limit radial movement of the base 91 relative to the housing 11 and the gear assembly 70.

The second engagement portion 92 is provided on the end portion 91a of the base 91. The second engagement portion 92 has a snap-fit arm 95 and an engagement surface 96. Note that the second engagement portion 92 is not limited to this example.

The snap-fit arm 95 extends obliquely from the end 91a of the base 91 toward the second central axis Ax2. Therefore, the end 95a of the snap-fit arm 95 in the first direction D1 is located radially inward from the end 95b of the snap-fit arm 95 in the second direction D2.

The engagement surface 96 is provided on the end 95a of the snap-fit arm 95. The engagement surface 96 may be provided at another position on the snap-fit arm 95. The engagement surface 96 is a curved surface that faces at least partially in the first direction D1. The engagement surface 96 is not limited to this example, and may face, for example, in another direction.

Figure 7 is a cross-sectional view showing a portion of the brake device 10 of this embodiment. As shown in Figure 7, the engagement surface 96 faces a first engagement portion 77 provided on the gear assembly 70. The engagement surface 96 abuts against the first engagement portion 77, thereby restricting the base 91 from moving in the first direction D1 relative to the housing 11 and the gear assembly 70. In other words, the engagement surface 96 catches on the first engagement portion 77 so as to restrict the base 91 from moving in the first direction D1 relative to the housing 11 and the gear assembly 70.

As described above, the first slider 75 and the first stopper 83 restrict the base 91 from moving in the circumferential direction relative to the housing 11 and the gear assembly 70. In addition, the wall portion 82, the first engaging portion 77, and the second engaging portion 92 restrict the base 91 from moving in the axial direction relative to the housing 11 and the gear assembly 70. This prevents the anti-rotation member 90 from falling out of the space S and keeps it in the space S.

The snap-fit arm 95 can be elastically deformed so that the engagement surface 96 moves radially outward. The snap-fit arm 95 elastically deforms so that the engagement surface 96 disengages from the first engagement portion 77. In other words, the snap-fit arm 95 elastically deforms to move the engagement surface 96 to a position that allows the base 91 to move in the first direction D1 relative to the housing 11 and the gear assembly 70.

As shown in FIG. 5, the protrusion 93 extends from the end 91a of the base 91 in the first direction D1. The two protrusions 93 extend substantially parallel to each other. The second engagement portion 92 is located between the two protrusions 93.

One protrusion 93 is spaced from the second engagement portion 92 in the first circumferential direction Da1. The other protrusion 94 is spaced from the second engagement portion 92 in the second circumferential direction Da2. The distance between the protrusion 93 and the second engagement portion 92 in the circumferential direction (first circumferential direction Da1) is shorter than the minimum length of the protrusion 93 in the circumferential direction (first circumferential direction Da1). In addition, the distance between the protrusion 93 and the second engagement portion 92 in the circumferential direction is shorter than the minimum length of the second engagement portion 92 in the circumferential direction (first circumferential direction Da1).

The two protrusions 93 are spaced inward from the side surfaces 91c and 91d of the base 91 in the circumferential direction. The two protrusions 93 are spaced from the side surface 75d of the first slider 75 and from the side surface 83a of the first stopper 83. This prevents the protrusions 93 from receiving loads from the first slider 75 and the first stopper 83.

In the axial direction, the length of the anti-rotation member 90 is equal to or shorter than the length of the peripheral wall 71. In addition, in the axial direction, the end 93a of the protrusion 93 in the first direction D1 is located at the same position as the end face 71c of the peripheral wall 71, or is spaced apart from the end face 71c in the second direction D2. In other words, the protrusion 93 does not protrude in the first direction D1 beyond the end face 71c of the peripheral wall 71. Note that the protrusion 93 is not limited to this example.

The color of the anti-rotation member 90 is different from the colors of the casing 21 and the ring gear 37. For example, the anti-rotation member 90 is white, and the casing 21 and the ring gear 37 are black. Therefore, the color of the first engagement portion 77 of the ring gear 37 is different from the color of the second engagement portion 92 of the anti-rotation member 90. Note that the anti-rotation member 90, the casing 21, and the ring gear 37 may have parts of the same color, as long as the colors of the first engagement portion 77 and the second engagement portion 92 are different from each other.

Figure 8 is a cross-sectional view that shows a schematic of the housing 11 and the gear assembly 70 during manufacturing of this embodiment. Figure 9 is a cross-sectional view that shows a schematic of the housing 11, the gear assembly 70, and the anti-rotation member 90 during manufacturing of this embodiment. Below, an example of assembly of the housing 11, the gear assembly 70, and the anti-rotation member 90 during manufacturing of the brake device 10 will be described.

First, as shown in FIG. 8, the gear assembly 70 is accommodated in the second recess 26. For example, the gear assembly 70 is inserted into the second recess 26 in the second direction D2 so that the side surface 75d of the first slider 75 slides on the side surface 83a of the first stopper 83.

Next, the gear assembly 70 is rotated in the first circumferential direction Da1 relative to the casing 21. This causes the first slider 75 to move away from the first stopper 83, and the side surface 75c of the first slider 75 to approach the side surface 84a of the second stopper 84. Furthermore, the second slider 76 is inserted between the wall portion 82 and the rail 85a of the holding portion 85, and slides on the rail 85a.

In the axial direction, the end 83b of the first stopper 83 in the first direction D1 is spaced from the first engagement portion 77 in the second direction D2. This prevents the first stopper 83 from interfering with the first engagement portion 77 while the gear assembly 70 rotates in the first circumferential direction Da1.

As shown in FIG. 9, the side surface 75c of the first slider 75 abuts against the side surface 84a of the second stopper 84, restricting further rotation of the gear assembly 70. Furthermore, the second slider 76 abuts against the rail 85a, restricting the gear assembly 70 from falling out of the second recess 26 in the first direction D1.

Next, the anti-rotation member 90 is inserted in the second direction D2 into the space S between the first slider 75 and the first stopper 83. That is, the second direction D2 is the insertion direction of the anti-rotation member 90.

As shown in FIG. 6, a groove 91g is provided on the inner surface 91e of the base 91. The groove 91g is recessed radially outward from the inner surface 91e and is provided from the end 91a to the end 91b. When the anti-rotation member 90 is inserted into the space S, the groove 91g is provided on the base 91, thereby preventing the first engagement portion 77 from interfering with the base 91.

While the anti-rotation member 90 is being inserted into the space S, the snap-fit arm 95 is pushed radially outward by the first engagement portion 77. This causes the snap-fit arm 95 to elastically deform, and the engagement surface 96 overcomes the first engagement portion 77.

As shown in FIG. 7, when the engagement surface 96 overcomes the first engagement portion 77, the elastic deformation of the snap-fit arm 95 is released, and the end portion 95a of the snap-fit arm 95 abuts against the outer peripheral surface 71a of the peripheral wall 71. Furthermore, the engagement surface 96 faces the first engagement portion 77. As a result, the engagement surface 96 restricts the movement of the anti-rotation member 90 in the first direction D1 relative to the housing 11 and the gear assembly 70. This completes the assembly of the housing 11, the gear assembly 70, and the anti-rotation member 90.

Figure 10 is a plan view of the brake device 10 of this embodiment viewed in the second direction D2. The second engagement portion 92 is provided at the end 91a of the base 91 in the first direction D1 where the second recess 26 is open. Therefore, while the anti-rotation member 90 is being inserted into the space S, the second engagement portion 92 is visible from the end 26a of the second recess 26 in the first direction D1.

When the brake device 10 is viewed in the second direction D2, the engagement surface 96 caught in the first engagement portion 77 is covered by the first engagement portion 77. Therefore, by visually checking whether the engagement surface 96 is covered by the first engagement portion 77, the worker can determine whether the first engagement portion 77 and the second engagement portion 92 are securely engaged.

Also, a camera may capture an image of the first engagement portion 77 and the second engagement portion 92. For example, a computer of the inspection device analyzes the image captured by the camera. The computer can determine from the image that the engagement surface 96 is covered by the first engagement portion 77 and is therefore not visible in the image, thereby determining whether the first engagement portion 77 and the second engagement portion 92 are securely engaged.

As described above, the second engagement portion 92 is white and the first engagement portion 77 is black. This makes it easy for the computer to determine whether the engagement surface 96 of the second engagement portion 92 is covered by the first engagement portion 77 based on the brightness of the image.

The space near the end 26a of the second recess 26 is left open so that the gear assembly 70 can be inserted into the second recess 26. This makes it easy to place a camera in that space, and there is no need to rotate the brake device 10 for inspection with the camera.

When the anti-rotation member 90 is inserted into the space S, for example, a jig abuts against the end 93a of the protrusion 93. The jig pushes the protrusion 93 in the second direction D2, moving away from the second engagement portion 92. This prevents the second engagement portion 92 from receiving a load from the jig.

In the brake device 10 according to the embodiment described above, the base 91 of the anti-rotation member 90 is interposed between the side surface 83a of the first stopper 83 of the housing 11 and the side surface 75d of the first slider 75 of the gear assembly 70, and restricts the relative movement of the housing 11 and the gear assembly 70 in the direction in which the side surface 83a and the side surface 75d approach each other. The second engagement portion 92 of the anti-rotation member 90 is provided at the end 91a of the base 91 in the first direction D1, and at least partially faces the first engagement portion 77 provided on one of the housing 11 and the gear assembly 70 to restrict the base 91 from moving in the first direction D1 relative to the housing 11 and the gear assembly 70. That is, the second engagement portion 92 that engages with the first engagement portion 77 is provided at the end 91a of the base 91 in the first direction D1. The second recess 26 in which the housing 11 is accommodated is open in the first direction D1. Therefore, for example, an operator or a camera can visually check whether the first engagement portion 77 and the second engagement portion 92 are engaged through the end 26a of the second recess 26 in the opened first direction D1. For example, when the second engagement portion 92 is provided at the end 91b of the base 91 in the second direction D2, the wall portion 82 protruding from the inner circumferential surface 81 of the second recess 26 covers the second engagement portion 92, so that the engagement between the first engagement portion 77 and the second engagement portion 92 is difficult to see unless a hole is provided in the wall portion 82. As described above, the brake device 10 of this embodiment can more reliably engage the first engagement portion 77 and the second engagement portion 92 during manufacturing, thereby improving the production efficiency of the brake device 10.

The first engagement portion 77 has a snap-fit arm 95 and an engagement surface 96. The snap-fit arm 95 is capable of elastically deforming to move the engagement surface 96 to a position that allows the base 91 to move in the first direction D1 relative to the housing 11 and the gear assembly 70. In this manner, by providing the anti-rotation member 90 with the elastically deforming snap-fit arm 95, the brake device 10 of this embodiment can prevent the shapes of the housing 11 and the gear assembly 70 from becoming complicated, and can improve the production efficiency of the brake device 10.

The engagement surface 96 is provided on the end 95a of the snap-fit arm 95 in the first direction D1. This allows, for example, an operator or a camera to easily visually check whether the first engagement portion 77 and the second engagement portion 92 are engaged. Therefore, the brake device 10 of this embodiment allows the first engagement portion 77 and the second engagement portion 92 to be more reliably engaged with each other during manufacturing, improving the production efficiency of the brake device 10.

The color of the first engagement portion 77 is different from the color of the second engagement portion 92. This allows, for example, an operator or a camera to easily visually determine whether the first engagement portion 77 and the second engagement portion 92 are engaged. Therefore, the brake device 10 of this embodiment allows the first engagement portion 77 and the second engagement portion 92 to be more reliably engaged with each other during manufacturing, improving the production efficiency of the brake device 10.

The anti-rotation member 90 has a protrusion 93 extending in the first direction D1 from the end 91a of the base 91 in the first direction D1. As a result, for example, when the anti-rotation member 90 is inserted into the space S between the side surface 83a of the first stopper 83 and the side surface 75d of the first slider 75, the protrusion 93 receives the load of the insertion work from, for example, a jig, and can prevent the load from acting on the second engagement portion 92. Therefore, the brake device 10 of this embodiment can prevent the second engagement portion 92 from being damaged by the load, and can prevent the engagement between the first engagement portion 77 and the second engagement portion 92 from being hindered by the load.

The anti-rotation member 90 has two protrusions 93 extending in the first direction D1 from the end 91a of the base 91 in the first direction D1. The second engagement portion 92 is located between the two protrusions 93. As a result, the two protrusions 93 surround the second engagement portion 92, and the load of the insertion operation can be prevented from acting on the second engagement portion 92. Therefore, the brake device 10 of this embodiment can prevent the second engagement portion 92 from being damaged by the load, and can also prevent the engagement between the first engagement portion 77 and the second engagement portion 92 from being hindered by the load.

The distance between the protrusion 93 and the second engagement portion 92 in the first circumferential direction Da1 is shorter than the minimum length of the protrusion 93 in the first circumferential direction Da1 and shorter than the minimum length of the second engagement portion 92 in the first circumferential direction Da1. This prevents, for example, the protrusion 93 or the second engagement portion 92 of one anti-rotation member 90 from entering the distance between the protrusion 93 and the second engagement portion 92 of another anti-rotation member 90. Therefore, the brake device 10 of this embodiment prevents the multiple anti-rotation members 90 from becoming entangled with each other, and can improve the production efficiency of the brake device 10.

Figure 11 is a cross-sectional view showing a portion of a brake device 10 according to a first modified example of this embodiment. In the modified example of Figure 11, instead of the first engagement portion 77 being provided on the gear assembly 70, the first engagement portion 100 is provided on the inner circumferential surface 81 of the casing 21. The first engagement portion 100 protrudes radially inward from the inner circumferential surface 81.

The engagement surface 96 of the second engagement portion 92 faces a first engagement portion 100 provided on the inner peripheral surface 81 of the housing 11. The engagement surface 96 abuts against the first engagement portion 100, thereby restricting the base 91 from moving in the first direction D1 relative to the housing 11 and the gear assembly 70. As described above, the first engagement portions 77, 100 may be provided on the housing 11 or on the gear assembly 70. The first engagement portions 77, 100 may also be provided on the housing 11 and the gear assembly 70.

Figure 12 is a cross-sectional view showing a portion of the brake device 10 according to a second modified example of this embodiment. In the modified example of Figure 12, the gear assembly 70 has a first engagement portion 101 instead of the first engagement portion 77. The first engagement portion 101 is a snap-fit arm and is elastically deformable.

The anti-rotation member 90 has a second engagement portion 102 instead of the second engagement portion 92. The second engagement portion 102 is provided on the end portion 91a of the base 91. The second engagement portion 102 faces the first engagement portion 101 and limits the movement of the base 91 in the first direction D1 relative to the housing 11 and the gear assembly 70.

The first engagement portion 101 can be elastically deformed to allow the base 91 to move in the first direction D1 relative to the housing 11 and the gear assembly 70. While the anti-rotation member 90 is inserted into the space S, the first engagement portion 101 is, for example, pressed by the base 91 and elastically deformed.

Although the above describes the embodiments of the present invention, the above embodiments and variations are merely examples and are not intended to limit the scope of the invention. The above embodiments and variations can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. In addition, the configurations and shapes of each embodiment and variation can be partially interchanged.

10... Brake device, 10a... Reduction gear, 11... Housing, 12... Motor, 13... Rotation transmission mechanism, 14... Rotation-to-linear conversion mechanism, 26... Second recess (hole), 36c... Pinion gear (gear), 37a... Outer gear (gear), 51... Brake pad (braking member), 52... Disc rotor (brake rotor), 61... Rotating member, 63... Linear member, 70... Gear assembly, 71a... Outer peripheral surface, 7 5d...side surface (second end), 77, 100, 101...first engagement portion, 81...inner surface, 82...wall portion, 83a...side surface (first end), 90...rotation prevention member, 91...base, 91a...end portion, 92, 102...second engagement portion, 93...projection portion, 95...snap-fit arm, 95a...end portion, 96...engagement surface, D1...first direction, D2...second direction, Da1...first circumferential direction, Da2...second circumferential direction.

Claims (7)

a housing having an opening in a first direction, the housing having an inner circumferential surface of the opening, a wall portion extending from the inner circumferential surface at a position spaced apart from an end of the opening in the first direction in a second direction opposite to the first direction, and a first end portion of the inner circumferential surface in the first circumferential direction;
a gear assembly received in the hole and having an outer circumferential surface facing the inner circumferential surface, a plurality of gears provided inside the outer circumferential surface and meshing with each other, and a second end portion spaced apart in the first circumferential direction from the first end portion in a second circumferential direction opposite to the first circumferential direction;
a rotation preventing member including: a base interposed between the first end and the second end and configured to restrict relative movement of the housing and the gear assembly in a direction in which the first end and the second end approach each other; and a second engaging portion provided at an end of the base in the first direction and at least partially facing a first engaging portion provided on one of the housing and the gear assembly and configured to restrict movement of the base in the first direction relative to the housing and the gear assembly;
Equipped with
the anti-rotation member has two protrusions extending in the first direction from an end of the base in the first direction,
The second engagement portion is located between the two protrusions.
Reduction gear. a housing having an opening in a first direction, the housing having an inner circumferential surface of the opening, a wall portion extending from the inner circumferential surface at a position spaced apart from an end of the opening in the first direction in a second direction opposite to the first direction, and a first end portion of the inner circumferential surface in the first circumferential direction;
a gear assembly received in the hole and having an outer circumferential surface facing the inner circumferential surface, a plurality of gears provided inside the outer circumferential surface and meshing with each other, and a second end portion spaced apart in the first circumferential direction from the first end portion in a second circumferential direction opposite to the first circumferential direction;
a rotation preventing member including: a base interposed between the first end and the second end and configured to restrict relative movement of the housing and the gear assembly in a direction in which the first end and the second end approach each other; and a second engaging portion provided at an end of the base in the first direction and at least partially facing a first engaging portion provided on one of the housing and the gear assembly and configured to restrict movement of the base in the first direction relative to the housing and the gear assembly;
Equipped with
the anti-rotation member has a protrusion extending in the first direction from an end of the base in the first direction,
the protruding portion is spaced from the second engaging portion in the first circumferential direction or the second circumferential direction,
a distance between the protruding portion and the second engaging portion in the first circumferential direction is shorter than a minimum length of the protruding portion in the first circumferential direction and is shorter than a minimum length of the second engaging portion in the first circumferential direction;
Reduction gear. the anti-rotation member has two protrusions extending in the first direction from an end of the base in the first direction,
The second engagement portion is located between the two protrusions.
The reduction gear according to claim 2. the second engagement portion has a snap-fit arm extending from an end of the base in the first direction, and an engagement surface provided on the snap-fit arm and facing the first engagement portion to limit movement of the base in the first direction relative to the housing and the gear assembly,
the snap-fit arm is capable of elastically deforming to move the engagement surface to a position that allows the base to move in the first direction relative to the housing and the gear assembly.
The reduction gear transmission according to any one of claims 1 to 3 . The reduction gear transmission of claim 4 , wherein the engagement surface is provided on an end of the snap-fit arm in the first direction. The reduction gear transmission according to claim 1 , wherein the first engagement portion is a different color from the second engagement portion. A reduction gear transmission according to any one of claims 1 to 6 , wherein the plurality of gears are driven by a motor;
a rotary-linear motion conversion mechanism including a rotary member rotated by the plurality of gears and a linear motion member that linearly moves in response to the rotation of the rotary member;
a braking member that is pressed against a brake rotor in response to the linear motion of the linear motion member;
A braking device comprising:

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