JP2020118234A - Reduction gear - Google Patents

Abstract

To provide a reduction gear capable of, for example, suppressing deformation of a housing.SOLUTION: A reduction gear in an embodiment, includes: a rotation transmission mechanism having a restriction member for restricting rotation of a first gear, and a second gear rotated by the first gear; a housing provided with a housing opening for housing the rotation transmission mechanism; and a cover for covering the housing opening. The restriction member has a second guide. The housing opening has a second housing portion for housing the second guide movable in a second direction. The housing has an inner face of the second housing portion for restricting rotation of the restriction member, and a first engagement portion positioned at one side in a third direction with respect to the second guide. The cover has an engagement portion positioned at one side in the third direction with respect to the second guide, separated from the housing, and engageable with a seat of a vehicle, and a second engagement portion to be engaged with the first engagement portion.SELECTED DRAWING: Figure 2

Description

Embodiments of the present invention relate to a speed reducer.

BACKGROUND ART Conventionally, there is known a speed reducer that reduces the rotation of a motor and outputs the speed from an internal gear by combining an external gear with an internal gear having more teeth than the external gear. The externally toothed gear revolves around the rotation axis to rotate the internal gear around the rotation axis. The speed reducer is provided with a guide plate that limits rotation of the external gear (Patent Document 1).

JP, 2008-080791, A

However, in the conventional configuration, the guide plate restricts the rotation of the external gear, so that a load acts on the housing of the reduction gear transmission from the guide plate. The load may deform the housing.

Therefore, the present invention has been made in view of the above, and provides a speed reducer capable of suppressing deformation of the housing.

The speed reducer according to the embodiment of the present invention includes, as an example, a driven gear that is rotated about a rotation axis by a driving force of a drive mechanism, and a first gear that is moved by the driven gear in the circumferential direction of the rotation axis. A rotation transmission mechanism having a limiting member that limits rotation of the first gear and a second gear that is rotated around the rotation shaft by the first gear, and faces in the axial direction of the rotation shaft. A housing having an outer surface and provided with an accommodation opening for accommodating the rotation transmission mechanism while opening to the outer surface, and a cover attached to the housing and covering the accommodation opening, the limiting member, A first guide that allows the first gear to move in a first direction orthogonal to the axial direction, and limits relative rotation of the limiting member and the first gear; and the first guide. A second guide orthogonal to the axial direction and projecting in a second direction different from the first direction, the accommodation opening including the driven gear, the first gear, and the second gear. First accommodation portion in which the gear and the first guide are accommodated, the first accommodation portion extending from the first accommodation portion in the second direction, and the restriction member movably in the second direction. A second accommodating portion for accommodating two guides, and the housing includes an inner surface of the second accommodating portion that limits relative rotation of the housing and the limiting member, and the second accommodating portion. A first engaging portion located on one side of a third direction orthogonal to the axial direction and orthogonal to the second direction with respect to the guide, and the cover includes the second guide. With respect to the third direction, is separated from the housing, and is connectable to a vehicle seat, and the one of the third direction with respect to the second guide. A second engaging portion that is located on a side and that engages with the first engaging portion to limit deformation of the housing such that the first engaging portion moves away from the rotation shaft. Have. Therefore, as an example, a part of the housing on one side in the third direction with respect to the second guide is suppressed from being deformed away from the rotation axis even when a load is input from the second guide. .. That is, the deformation of the housing is suppressed.

In the speed reducer, as an example, an opening is provided in one of the first engaging portion and the second engaging portion, and the other of the first engaging portion and the second engaging portion is provided. Has a protrusion fitted in the opening. Therefore, as an example, a part of the housing on one side in the third direction with respect to the second guide is not only deformed away from the rotation axis, but also deformed toward the rotation axis or in the circumferential direction of the rotation axis. Deformation is suppressed. Therefore, the deformation of the housing is suppressed.

In the above reduction gear transmission, as an example, the first engagement portion has a first wall, and the second engagement portion is located outside the first wall in the radial direction of the rotary shaft. And has a pawl located and extending along the first wall. Therefore, as an example, the reduction gear transmission is prevented from increasing in the radial direction.

In the speed reducer, as an example, the first engagement portion has a second wall that is located between the pawl and the second guide in the circumferential direction and faces the pawl. For example, a part of the housing on one side in the third direction with respect to the second guide is deformed so as to move in the circumferential direction when a load is input from the second guide in the circumferential direction. However, the deformation is suppressed by the claw supporting the second wall. Therefore, the deformation of the housing is suppressed.

In the speed reducer, as an example, the first engaging portion has a third wall facing the claw, and the claw includes the second wall and the third wall in the circumferential direction. Located in between. For example, when a load is input from the second guide in the circumferential direction, a part of the housing on one side of the second guide in the third direction is twisted so as to move in the circumferential direction and move away from the rotation axis. Be done. Due to the twist, the housing inputs a load to the claw. However, since the third wall supports the nail, the deformation of the nail is suppressed.

In the speed reducer, as an example, the first engaging portion is located outside the claw in the radial direction of the rotation shaft, and is connected to the second wall and the third wall. It has 4 walls. Therefore, as an example, the first to fourth walls are formed in a frame shape, and the rigidity of the first engaging portion is improved.

FIG. 1 is an exemplary side view schematically showing a seat according to the first embodiment. FIG. 2 is an exemplary side view schematically showing the driving device of the first embodiment. FIG. 3 is an exemplary front view schematically showing the drive device according to the first embodiment. FIG. 4 is an exemplary cross-sectional view schematically showing the drive device according to the first embodiment along the line F4-F4 of FIG. FIG. 5 is an exemplary perspective view schematically showing the drive device of the first embodiment in a disassembled state. FIG. 6 is an exemplary cross-sectional view schematically showing a part of the housing and a part of the stopper plate of the first embodiment, taken along line F6-F6 of FIG. FIG. 7 is a side view showing the housing and the stopper plate of the first embodiment. FIG. 8 is an exemplary side view schematically showing the housing of the first embodiment. FIG. 9 is an exemplary side view schematically showing a part of the housing and a part of the stopper plate of the first embodiment. FIG. 10 is an exemplary perspective view schematically showing the housing and the washer of the first embodiment. FIG. 11 is an exemplary cross-sectional view schematically showing the speed reducer according to the second embodiment.

(First embodiment)
The first embodiment will be described below with reference to FIGS. 1 to 10. In addition, in this specification, a plurality of expressions may be described with respect to the constituent elements and the description of the constituent elements according to the embodiment. The components and the description having a plurality of expressions may have other expressions not described. Further, components and explanations that are not expressed in plural may be expressed in other expressions not described.

FIG. 1 is an exemplary side view schematically showing a seat 11 according to the first embodiment. The seat 11 is mounted on a vehicle 1 such as a four-wheeled vehicle. The seat 11 is provided with, for example, a slide rail 12 and a seat lifter 13.

The slide rail 12 allows the seat 11 to slide in the front-rear direction of the vehicle 1. The slide rail 12 includes, for example, a pair of upper rails 21 and a pair of lower rails 22. The lower rail 22 is attached to the floor 1a of the vehicle 1. The upper rail 21 is attached to the lower rail 22 so as to be slidable in the front-rear direction of the vehicle 1.

The seat lifter 13 can move the seat 11 up and down in the vertical direction of the vehicle 1. The seat lifter 13 includes, for example, a pair of base plates 24, a pair of arms 25, a pair of front links 26, a pair of rear links 27, a rod 28, and a drive device 29. The drive device 29 may be referred to as a gearbox motor, for example.

The base plate 24 is attached to the upper rail 21. The arm 25 is attached to the base plate 24 via a front link 26 and a rear link 27 so as to be vertically movable in the vehicle 1.

One end of the front link 26 is rotatably attached to the front end of the base plate 24 by, for example, a pin. The other end of the front link 26 is rotatably attached to the front end of the arm 25 by, for example, a pin.

One end of the rear link 27 is rotatably attached to the rear end of the base plate 24 by, for example, a pin. The other end of the rear link 27 is rotatably attached to the rear end of the arm 25 by, for example, a rod 28. The pair of arms 25 are connected to each other by a rod 28.

In the seat lifter 13, the base plate 24, the arm 25, the front link 26, and the rear link 27 form a four-bar rotation mechanism. By rotating the front link 26 or the rear link 27, the arm 25 moves up and down with respect to the base plate 24.

The rear link 27 is provided with a gear portion 27a. The gear portion 27a has a plurality of teeth arranged in a substantially arc shape with the rod 28 as the center. The drive device 29 is attached to the arm 25 together with the rear link 27 having the gear portion 27a. The drive device 29 has a pinion 29a. The pinion 29a is fitted to the gear portion 27a of the rear link 27.

When the drive device 29 is driven, the pinion 29a rotates. The pinion 29a that meshes with the gear portion 27a rotates the rear link 27. As a result, the arm 25 moves up and down with respect to the base plate 24.

FIG. 2 is an exemplary side view schematically showing the drive device 29 of the first embodiment. FIG. 3 is an exemplary front view schematically showing the drive device 29 of the first embodiment. FIG. 4 is an exemplary cross-sectional view schematically showing the drive device 29 of the first embodiment taken along line F4-F4 of FIG. FIG. 5 is an exemplary perspective view schematically showing the drive device 29 of the first embodiment in a disassembled state.

As shown in FIG. 2, the drive device 29 includes a motor 31 and a speed reducer 32. The motor 31 may be referred to as a drive mechanism, for example. The drive device 29 reduces the rotation of the motor 31 by the reduction device 32 and rotates the pinion 29a.

As shown in FIG. 5, the motor 31 has a case 31a and components housed in the case 31a. Components include, for example, motor shafts, stators, rotors, coils, and magnets. The motor 31 is driven by electric power and rotates the motor shaft around the rotation axis Ax1.

The speed reducer 32 is a so-called Taumel mechanism, and includes a rotation transmission mechanism 35, a housing 36, a cover 37, and a washer 38. The rotation transmission mechanism 35 may be referred to as a speed reducer, for example. The cover 37 may be referred to as a cap, for example.

The rotation transmission mechanism 35 is housed in the housing 36. The rotation transmission mechanism 35 includes a first speed reducer 41, a second speed reducer 42, and an output shaft 43. The driving force of the motor 31 is transmitted to the second reduction gear unit 42 via the first reduction gear unit 41, and is further transmitted from the second reduction gear unit 42 to the output shaft 43.

The output shaft 43 is rotatably supported by the housing 36 and the cover 37 about the rotation axis Ax2. The rotation axis Ax2 is a central axis of the output shaft 43 that extends in a direction intersecting the axial direction of the rotation axis Ax1. The rotation axis Ax2 may be referred to as a rotation axis or a first rotation axis.

In the following description, the axial direction is defined as a direction along a rotation axis such as the rotation axis Ax1 and the rotation axis Ax2. Furthermore, the radial direction is defined as the direction orthogonal to the rotation axis, and the circumferential direction is defined as the direction of rotation around the rotation axis.

The pinion 29 a of the drive device 29 is provided on the output shaft 43. The pinion 29 a projects to the outside of the housing 36. The pinion 29a can rotate around the rotation axis Ax2 integrally with the output shaft 43.

The first reduction gear unit 41 has a worm 51 and a worm wheel 52. The worm wheel 52 may be referred to as a driven gear. The worm 51 is coupled to the motor shaft of the motor 31 and rotates integrally with the motor shaft around the rotation axis Ax1.

As shown in FIG. 4, the worm wheel 52 is rotatably supported by the housing 36 and the output shaft 43 around the rotation axis Ax2. The worm wheel 52 is formed in a substantially disc shape around the rotation axis Ax2, and has a first end surface 52a, a second end surface 52b, a plurality of teeth 52c, and a support protrusion 52d. The first end surface 52a faces one side in the axial direction of the rotation axis Ax2 (upward in FIG. 4). The second end surface 52b is located on the opposite side of the first end surface 52a. The second end surface 52b faces the other axial side of the rotation axis Ax2 (downward in FIG. 4) and is supported by the housing 36. The plurality of teeth 52c are arranged at substantially equal intervals in the circumferential direction of the rotation axis Ax2 and mesh with the worm 51. The support protrusion 52d projects from the second end surface 52b and extends in the circumferential direction of the rotation axis Ax2.

In the first reduction gear 41, when the worm 51 rotates about the rotation axis Ax1 by the driving force of the motor 31, the worm wheel 52 rotates about the rotation axis Ax2. That is, the worm wheel 52 is rotated about the rotation axis Ax2 by the driving force of the motor 31. The first deceleration unit 41 decelerates with respect to the motor shaft of the motor 31 to rotate the worm wheel 52.

The second reduction gear unit 42 includes an eccentric shaft 61, an external gear 62, a bush 63, a stopper plate 64, and an internal gear 65. The external gear 62 may be referred to as a first gear or a gear. The stopper plate 64 may be referred to as a limiting member. Internal gear 65 may be referred to as a second gear or gear. In the present embodiment, the eccentric shaft 61 is a component integrated with the worm wheel 52, and the internal gear 65 is a component integrated with the output shaft 43.

The eccentric shaft 61 projects from the first end surface 52a of the worm wheel 52 along the rotation axis Ax3. The rotation axis Ax3 may be referred to as a second rotation axis. The rotation axis Ax3 is parallel to the rotation axis Ax2 and is at a position different from the rotation axis Ax2. That is, the rotation axis Ax3 that is the center of the eccentric shaft 61 is eccentric from the rotation axis Ax2 that is the center of the worm wheel 52.

The eccentric shaft 61 has an outer peripheral surface 61a. The outer peripheral surface 61a is a substantially cylindrical outer surface centered on the rotation axis Ax3, and faces the outer side in the radial direction of the rotation axis Ax3. Further, the eccentric shaft 61 is provided with an insertion hole 61b. The insertion hole 61b extends along the rotation axis Ax2. The rotation axis Ax3, which is the center of the outer peripheral surface 61a, is eccentric from the rotation axis Ax2, which is the center of the insertion hole 61b. The output shaft 43 is rotatably supported by the eccentric shaft 61 by being inserted into the insertion hole 61b. The output shaft 43, the worm wheel 52, and the eccentric shaft 61 are rotatable relative to each other.

The outer peripheral surface 61a has a first portion 61aa and a second portion 61ab. The first portion 61aa and the second portion 61ab are arranged in the axial direction of the rotation axis Ax3. The surface roughness of the first portion 61aa is made lower than the surface roughness of the second portion 61ab by, for example, cutting or grinding.

The eccentric shaft 61 can rotate integrally with the worm wheel 52. By the worm wheel 52 rotating around the rotation axis Ax2, the portion of the eccentric shaft 61 having at least the outer peripheral surface 61a is moved in the circumferential direction of the rotation axis Ax2. In other words, the eccentric shaft 61 revolves around the rotation axis Ax2. Along with the eccentric shaft 61, the rotating shaft Ax3 also moves (revolves) in the circumferential direction of the rotating shaft Ax2.

The external gear 62 is formed in a plate shape centering on the rotation axis Ax3. The external gear 62 is provided with an insertion hole 62a extending along the rotation axis Ax3. The eccentric shaft 61 is inserted into the insertion hole 62a so as to be rotatable relative to the external gear 62 around the rotation axis Ax3.

With the rotating worm wheel 52 and the revolving eccentric shaft 61, the external gear 62 is moved in the circumferential direction of the rotation axis Ax2 while drawing a circular locus whose radius is the distance between the rotation axis Ax2 and the rotation axis Ax3. To be In other words, the external gear 62 revolves around the rotation axis Ax2.

The external gear 62 has a first plane 62b, a second plane 62c, a concave surface 62d, a convex surface 62e, a plurality of external teeth 62f, a flange 62g, and two guide protrusions 62h shown in FIG. And an inner peripheral surface 62i. The first plane 62b may be referred to as the fourth plane. The second plane 62c may be referred to as the fifth plane. The concave surface 62d may be referred to as the first surface. The convex surface 62e may be referred to as the second surface. The external tooth 62f may be referred to as a first tooth.

The first flat surface 62b is a substantially flat annular surface that faces one side in the axial direction of the rotation axis Ax3. The second plane 62c is a substantially flat annular surface located on the opposite side of the first plane 62b and facing the other side in the axial direction of the rotation axis Ax3.

The concave surface 62d is a substantially flat surface that is recessed from the first flat surface 62b and closer to the second flat surface 62c than the first flat surface 62b. The concave surface 62d faces the one side in the axial direction of the rotation axis Ax3 and is located inside the first plane 62b in the radial direction of the rotation axis Ax3. One end of the insertion hole 62a opens at the concave surface 62d.

The convex surface 62e is a substantially flat surface that projects from the second flat surface 62c and is farther from the first flat surface 62b than the second flat surface 62c. The convex surface 62e is located on the opposite side of the concave surface 62d and faces the other side in the axial direction of the rotation axis Ax3. The convex surface 62e is located inside the second flat surface 62c in the radial direction of the rotation axis Ax3. The other end of the insertion hole 62a opens at the convex surface 62e. The second flat surface 62c and the convex surface 62e face the worm wheel 52 with a space therebetween.

The outer teeth 62f are located outside the first plane 62b in the radial direction of the rotation axis Ax3. The outer teeth 62f project outward in the radial direction of the rotation axis Ax3 and are arranged at substantially equal intervals in the circumferential direction of the rotation axis Ax3.

The flange 62g is a substantially annular portion that surrounds the second plane 62c. The flange 62g is connected to the second flat surface 62c so as to project from the second flat surface 62c to the other side in the axial direction of the rotation axis Ax3.

As shown in FIG. 5, the guide protrusion 62h projects from the flange 62g to the other side in the axial direction of the rotating shaft Ax3. The two guide protrusions 62h are separated from each other in the first direction D1. The first direction D1 is a direction orthogonal to the axial direction of the rotation axis Ax2 (rotation axis Ax3). The insertion hole 62a, the second flat surface 62c, and the convex surface 62e are located between the two guide protrusions 62h in the first direction D1.

The first plane 62b, the second plane 62c, the concave surface 62d, the convex surface 62e, the outer teeth 62f, the flange 62g, and the guide protrusion 62h are formed by, for example, half blanking (embossing, half punching, half shearing). To be done. Therefore, as shown in FIG. 4, the distance (thickness) between the first plane 62b and the second plane 62c is equal to the distance (thickness) between the concave surface 62d and the convex surface 62e, and It is equal to the thickness of the flange 62g. The processing method and the thickness of the external gear 62 are not limited to this example.

The inner peripheral surface 62i forms an insertion hole 62a. In other words, the inner peripheral surface 62i is the edge of the insertion hole 62a. The inner peripheral surface 62i faces the outer peripheral surface 61a of the eccentric shaft 61 via the bush 63.

The bush 63 is made of, for example, a synthetic resin. The bush 63 may be made of another material. The bush 63 has a tubular portion 63a, a first collar portion 63b, and a second collar portion 63c. In addition, the bush 63 may omit one of the first flange portion 63b and the second flange portion 63c.

The tubular portion 63a is formed in a substantially cylindrical shape and is press-fitted into the insertion hole 62a of the external gear 62. The tubular portion 63a contacts the inner peripheral surface 62i of the external gear 62 and is interposed between the inner peripheral surface 62i and the outer peripheral surface 61a of the eccentric shaft 61. The tubular portion 63a contacts the first portion 61aa of the outer peripheral surface 61a. The friction coefficient at the contact portion between the tubular portion 63a and the first portion 61aa is lower than the friction coefficient when the tubular portion 63a and the second portion 61ab contact each other. The second portion 61ab of the outer peripheral surface 61a is separated from the bush 63 in the axial direction of the rotation axis Ax3.

The first flange portion 63b is formed in a substantially annular shape by protruding from the cylindrical portion 63a to the outside in the radial direction of the rotation axis Ax3. The first collar portion 63b contacts the concave surface 62d of the external gear 62. The outer diameter of the first collar portion 63b is smaller than the outer diameter of the concave surface 62d.

The second flange portion 63c is formed in a substantially annular shape by protruding from the cylindrical portion 63a to the outside in the radial direction of the rotation axis Ax3. The second flange 63c contacts the convex surface 62e of the external gear 62. Part of the external gear 62 is held between the first flange portion 63b and the second flange portion 63c. Therefore, the external gear 62 and the bush 63 are restricted from moving relatively in the axial direction of the rotation axis Ax3.

In the bush 63 of this embodiment, the first collar portion 63b is formed in advance. The second collar portion 63c is formed, for example, by caulking after the external gear 62 is press-fitted into the tubular portion 63a. The first flange 63b may be formed by crimping.

The stopper plate 64 is located between the worm wheel 52 and the external gear 62 in the axial direction of the rotation shaft Ax2 (rotation shaft Ax3). The stopper plate 64 is supported by the housing 36 and also supports the external gear 62.

The stopper plate 64 is made of metal, for example. The stopper plate 64 may be made of another material. The stopper plate 64 is molded by, for example, press working. Therefore, the stopper plate 64 has a sag surface 64a and a burr surface 64b. The sag surface 64a may be referred to as a first surface. The burr surface 64b may be referred to as the second surface.

The sagging surface 64a is a substantially flat surface facing one side in the axial direction of the rotation axis Ax2. The sag surface 64a faces the external gear 62 and supports the flange 62g of the external gear 62. The burr surface 64b is on the opposite side of the sag surface 64a, and is a substantially flat surface facing the other side in the axial direction of the rotation axis Ax2. A part of the burr surface 64b faces the housing 36 and is supported by the housing 36. The other part of the burr surface 64b faces the worm wheel 52 with a gap.

FIG. 6 is an exemplary cross-sectional view schematically showing a part of the housing 36 and a part of the stopper plate 64 of the first embodiment taken along line F6-F6 of FIG. As shown in FIG. 6, the stopper plate 64 has a hanging edge portion 64c and a protruding edge portion 64d.

The hanging edge portion 64c is a so-called dull (shear drop), and is a portion that hangs (is recessed) from the edge of the sag surface 64a toward the burr surface 64b. The protruding edge portion 64d is a so-called burr, and is a portion protruding from the edge of the burr surface 64b to the other side in the axial direction of the rotation axis Ax2. The other side of the rotation axis Ax2 in the axial direction is a direction away from the sag surface 64a. The hanging edge portion 64c and the protruding edge portion 64d may be formed by a method different from press working.

FIG. 7 is a side view showing the housing 36 and the stopper plate 64 of the first embodiment. As shown in FIG. 7, the stopper plate 64 has a first guide 71 and two second guides 72.

The first guide 71 and the second guide 72 are arranged in the second direction D2. The second direction D2 is a direction orthogonal to the axial direction of the rotation axis Ax2 (rotation axis Ax3) and different from the first direction D1. In the present embodiment, the second direction D2 is a direction orthogonal to the first direction D1. The first guide 71 and the second guide 72 have a sag surface 64a and a burr surface 64b, respectively.

The first guide 71 is formed in a rotationally symmetrical and mirror image symmetrical shape. The shape of the first guide 71 is not limited to this example. The first guide 71 is provided with an insertion hole 71a and two guide grooves 71b. The insertion hole 71a and the guide groove 71b respectively extend in the axial direction of the rotation axis Ax2 and open on the sag surface 64a and the burr surface 64b of the first guide 71.

The insertion hole 71a is located substantially in the center of the first guide 71. As shown in FIG. 4, the eccentric shaft 61 is inserted into the insertion hole 71a. The diameter of the insertion hole 71a is larger than the diameter of the outer peripheral surface 61a of the eccentric shaft 61. The eccentric shaft 61 is separated from the stopper plate 64 even if it moves in the circumferential direction of the rotation axis Ax2.

As shown in FIG. 7, the two guide grooves 71b are separated from each other in the first direction D1. In the present embodiment, the guide groove 71b is a notch that opens at the end of the first guide 71 in the first direction D1. The guide groove 71b is not limited to this example. The insertion hole 71a is located between the two guide grooves 71b in the first direction D1.

The guide protrusion 62h of the external gear 62 is fitted into the corresponding guide groove 71b. The guide protrusion 62h is supported by the first guide 71 so as to be movable along the guide groove 71b in the first direction D1. As a result, the first guide 71 allows movement of the external gear 62 in the first direction D1 and limits relative rotation of the stopper plate 64 and the external gear 62 about the rotation axis Ax3. Note that the first guide 71 may limit the relative rotation of the stopper plate 64 and the external gear 62 by other means so that the external gear 62 can move in the first direction D1.

The two second guides 72 project from the first guide 71 to one side and the other side of the second direction D2. In other words, the two second guides 72 project from the first guide 71 in opposite directions.

Hereinafter, one of the second guides 72 may be referred to as a second guide 72A and the other may be referred to as a second guide 72B. In the description common to the second guides 72A and 72B, the second guides 72A and 72B are simply referred to as the second guide 72.

The center C1 of the second guide 72A is different from the center C2 of the second guide 72B in the third direction D3 that is orthogonal to the axial direction of the rotation axis Ax2 (rotation axis Ax3) and is orthogonal to the second direction D2. In position. In the present embodiment, the third direction D3 is substantially the same as the first direction D1. The third direction D3 and the first direction D1 may be different.

In the present embodiment, the center C1 of the second guide 72A is substantially at the same position as the center C3 of the stopper plate 64 in the third direction D3. On the other hand, in the third direction D3, the center C2 of the second guide 72B is at a position different from the center C3 of the stopper plate 64.

The second guides 72 each have a first side edge 72a and a second side edge 72b. The first side edge 72a faces one side of the third direction D3 (upward in FIG. 7) and extends in the second direction D2. The second side edge 72b faces the other side (downward in FIG. 7) of the third direction D3 and extends in the second direction D2.

The first side edge 72a of the second guide 72A and the first side edge 72a of the second guide 72B are arranged on the same line. In other words, in the third direction D3, the first side edge 72a of the second guide 72A and the first side edge 72a of the second guide 72B are at substantially the same position.

On the other hand, in the third direction D3, the second side edge 72b of the second guide 72A is at a position different from the second side edge 72b of the second guide 72B. Therefore, the length (width) of the second guide 72A and the length (width) of the second guide 72B are different in the third direction D3.

The positions and widths of the second guides 72A and 72B are not limited to the above example. For example, in the third direction D3, both the center C1 of the second guide 72A and the center C2 of the second guide 72B may be at positions different from the center C3 of the stopper plate 64.

The second guide 72 is supported by the housing 36 so as to be movable in the second direction D2. As a result, the stopper plate 64 is restricted from rotating relative to the housing 36 about the center C3.

As described above, the stopper plate 64 limits the rotation (rotation) of the external gear 62 around the rotation axis Ax3. Therefore, the external gear 62 is translated (revolves) in the circumferential direction of the rotation axis Ax2 while being restricted from rotating.

As shown in FIG. 4, the internal gear 65 is formed in a plate shape centering on the rotation axis Ax2. The output shaft 43 can rotate integrally with the internal gear 65 and the rotation shaft Ax2.

The internal gear 65 has a flat surface 65b, a flange 65c, and a plurality of internal teeth 65d. The flat surface 65b may be referred to as a third surface. The inner teeth 65d may be referred to as second teeth.

The flat surface 65b is a substantially flat surface that faces the other side in the axial direction of the rotation axis Ax2. The flat surface 65b faces the first flat surface 62b of the external gear 62 through the gap. The plane surface 65b may be in contact with the first plane surface 62b.

The distance between the flat surface 65b and the first flat surface 62b of the external gear 62 is shorter than the distance between the flat surface 65b and the concave surface 62d. That is, the first flat surface 62b is closer to the flat surface 65b than the concave surface 62d. The distance between the flat surface 65b and the concave surface 62d is longer than the thickness of the bush 63. Therefore, the first flange portion 63b of the bush 63 is separated from the flat surface 65b.

The flange 65c is a substantially annular portion that surrounds the flat surface 65b. The flange 65c is connected to the flat surface 65b so as to project from the flat surface 65b to the other side in the axial direction of the rotation axis Ax2. The flange 65c is supported by the flange 62g of the external gear 62.

The inner teeth 65d project from the flange 65c to the inner side in the radial direction of the rotating shaft Ax2 and are arranged at substantially equal intervals in the circumferential direction of the rotating shaft Ax2. At least one of the internal teeth 65d meshes with at least one of the external teeth 62f of the external gear 62.

In the present embodiment, the number of inner teeth 65d is larger than the number of outer teeth 62f. For example, the number of inner teeth 65d is one or two more than the number of outer teeth 62f. The inner teeth 65d and the outer teeth 62f mesh at one place. When the external gear 62 moves in the circumferential direction of the rotation axis Ax2, the meshing portion between the internal teeth 65d and the external teeth 62f moves around the rotation axis Ax2, and the internal gear 65 rotates around the rotation axis Ax2. That is, the internal gear 65 is rotated about the rotation axis Ax2 by the external gear 62.

In the second deceleration portion 42, the number of the internal teeth 65d is larger than the number of the external teeth 62f, so the internal gear 65 decelerates and rotates with respect to the worm wheel 52. The output shaft 43 attached to the internal gear 65 and the pinion 29a provided on the output shaft 43 rotate integrally with the internal gear 65. The external gear 62 and the internal gear 65 transmit rotation between the worm wheel 52 and the output shaft 43.

The housing 36 is made of, for example, a synthetic resin. Note that the housing 36 may be made of another material such as metal. As shown in FIG. 5, the housing 36 has a motor holding portion 81 and a mechanism holding portion 82.

A mounting opening 84 is provided in the motor holding portion 81. The mounting opening 84 is a hole that opens in the axial direction of the rotation axis Ax1. The motor 31 is attached to the motor holding portion 81 by being fitted into the attachment opening 84.

The mechanism holding portion 82 is formed integrally with the motor holding portion 81. The mechanism holding portion 82 has an outer surface 82a that faces one side in the axial direction of the rotation axis Ax2. An accommodation opening 85 is provided in the mechanism holding portion 82. The accommodation opening 85 is a bottomed hole that opens to the outer surface 82a. The accommodation opening 85 communicates with the mounting opening 84. The rotation transmission mechanism 35 and the washer 38 are housed in the housing opening 85.

FIG. 8 is an exemplary side view schematically showing the housing 36 of the first embodiment. As shown in FIG. 8, the accommodation opening 85 has a first accommodation portion 87 and two second accommodation portions 88.

As shown in FIG. 4, in the first housing portion 87, the output shaft 43, the worm wheel 52, the eccentric shaft 61, the external gear 62, the bush 63, the first guide 71 of the stopper plate 64, and the internal gear 65. Is housed. The housing 36 has an inner surface 87a and a bottom surface 87b of the first accommodating portion 87. The inner surface 87a of the first accommodation portion 87 may be referred to as the inner surface of the accommodation opening. The bottom surface 87b of the first accommodation portion 87 may be referred to as the bottom surface of the accommodation opening.

The inner surface 87a of the first accommodating portion 87 faces the inner side in the radial direction of the rotation axis Ax2 and faces the rotation transmission mechanism 35 via a gap. The bottom surface 87b of the first accommodating portion 87 faces one side in the axial direction of the rotation axis Ax2 and faces the rotation transmission mechanism 35 with a gap.

As shown in FIG. 8, the housing 36 further includes a first support portion 91, a second support portion 92, and a plurality of ribs 93. The first support portion 91, the second support portion 92, and the rib 93 each project from the bottom surface 87b of the first accommodating portion 87.

The first support portion 91 and the second support portion 92 are each formed in a substantially annular shape extending in the circumferential direction of the rotation axis Ax2. The first support portion 91 and the second support portion 92 are not limited to this example, and may be formed by, for example, a plurality of protrusions protruding from the bottom surface 87b and arranged in the circumferential direction of the rotation axis Ax2. The first support portion 91 and the second support portion 92 are separated from the inner surface 87a of the first accommodating portion 87 inward in the radial direction of the rotation axis Ax2.

The inner diameter of the first support portion 91 is larger than the outer diameter of the second support portion 92. Therefore, the second support portion 92 is separated from the first support portion 91 inward in the radial direction of the rotation axis Ax2. The output shaft 43 is fitted inside the second support portion 92. As a result, the second support portion 92 supports the output shaft 43 rotatably around the rotation axis Ax2.

The rib 93 extends between the first support portion 91 and the second support portion 92 in the radial direction of the rotation axis Ax2. In other words, the ribs 93 extend radially. The rib 93 is connected to the first support portion 91 and the second support portion 92.

The two second accommodating portions 88 extend from the first accommodating portion 87 to one side and the other side of the second direction D2. As shown in FIG. 7, the corresponding second guide 72 is housed in the second housing portion 88 so as to allow the movement of the stopper plate 64 in the second direction D2. The housing 36 has an inner surface 88a and a bottom surface 88b, respectively, of the second storage portion 88.

The inner surface 88a of the second accommodating portion 88 faces the first side edge 72a and the second side edge 72b of the second guide 72. The inner surface 88 a supports the second guide 72, thereby limiting the relative rotation of the housing 36 and the stopper plate 64. That is, the second guide 72 is housed in the second housing portion 88 so as to limit the relative rotation of the housing 36 and the stopper plate 64.

As shown in FIG. 4, the bottom surface 88b of the second accommodating portion 88 faces the one side in the axial direction of the rotation axis Ax2 and faces the corresponding burr surface 64b of the second guide 72 via a gap. The bottom surface 88b is closer to the stopper plate 64 than the bottom surface 87b of the first accommodating portion 87.

The housing 36 further has two protrusions 95. Each of the protrusions 95 protrudes from the bottom surface 88b of the corresponding second accommodation portion 88 and supports the corresponding burr surface 64b of the second guide 72. As a result, the protruding edge portion 64d of the stopper plate 64 is separated from the bottom surface 88b.

As shown in FIG. 8, the protruding portion 95 is separated from the inner surface 88 a of the second accommodating portion 88. In the third direction D3, the center of the protruding portion 95 is located at the center of the bottom surface 88b of the corresponding second accommodating portion 88. The projecting portion 95 is located at an end of the corresponding bottom surface 88b in the second direction D2 that is closer to the first accommodating portion 87. On the other hand, the protruding portion 95 is separated from the end of the corresponding bottom surface 88b in the second direction D2 that is far from the first accommodating portion 87. By being arranged as described above, the protruding portion 95 is separated from the protruding edge portion 64d.

As shown in FIG. 7, the housing 36 has an engagement wall 101, an engagement protrusion 102, a first positioning protrusion 103, and a second positioning protrusion 104. The engagement wall 101 and the engagement protrusion 102 can each be referred to as a first engagement portion. The engagement protrusion 102 may be referred to as a protrusion. The engagement wall 101 and the engagement protrusion 102 are located on one side of the third direction D3 (upward in FIGS. 7 and 8) with respect to the second guide 72.

The engagement wall 101 is closer to the second guide 72B than the engagement protrusion 102 in the circumferential direction of the rotation axis Ax2. The engagement protrusion 102 is closer to the second guide 72A than the engagement wall 101 in the circumferential direction of the rotation axis Ax2.

FIG. 9 is an exemplary side view schematically showing a part of the housing 36 and a part of the stopper plate 64 of the first embodiment. As shown in FIG. 9, the engagement wall 101 is provided with an opening 101a. The opening 101a is a bottomed hole that opens to the outer surface 82a of the mechanism holding portion 82 at a position spaced from the first accommodating portion 87 to the outside in the radial direction of the rotation axis Ax2.

The engagement wall 101 has a first wall 101b, a second wall 101c, a third wall 101d, and a fourth wall 101e. The first wall 101b is located between the opening 101a and the first accommodating portion 87.

The second wall 101c and the third wall 101d project outward from the first wall 101b in the radial direction of the rotation axis Ax2. The opening 101a is located between the second wall 101c and the third wall 101d in the circumferential direction of the rotation axis Ax2. The second wall 101c is closer to the second guide 72B than the third wall 101d.

The fourth wall 101e is connected to the second wall 101c and the third wall 101d. The opening 101a is formed by the first wall 101b, the second wall 101c, the third wall 101d, and the fourth wall 101e.

As shown in FIG. 8, the engaging protrusion 102, the first positioning protrusion 103, and the second positioning protrusion 104 are each formed in a substantially cylindrical shape and protrude from the outer surface 82 a of the mechanism holding portion 82. The diameter and the cross-sectional area of the engagement protrusion 102 are larger than the diameter and the cross-sectional area of the first positioning protrusion 103, and larger than the diameter and the cross-sectional area of the second positioning protrusion 104. Furthermore, the engagement protrusion 102 is located outside the first positioning protrusion 103 in the radial direction of the rotation axis Ax2.

The first positioning protrusion 103 is located on one side of the second guide 72 in the third direction D3. The second positioning protrusion 104 is located on the other side in the third direction D3 (downward in FIGS. 7 and 8) with respect to the second guide 72.

Two fixing holes 108 are provided in the housing 36. The fixing hole 108 opens on the outer surface 82 a of the mechanism holding portion 82.

The fixing hole 108 is located on the other side in the third direction D3 with respect to the second guide 72.

The first positioning protrusion 103 is located between the engagement wall 101 and the engagement protrusion 102 in the circumferential direction of the rotation axis Ax2. Therefore, the engagement wall 101 is located between the second guide 72B and the first positioning protrusion 103 in the circumferential direction of the rotation axis Ax2. Further, the engagement protrusion 102 is located between the second guide 72A and the first positioning protrusion 103 in the circumferential direction of the rotation axis Ax2.

As shown in FIG. 4, the cover 37 is made of metal, for example. The cover 37 may be made of other material such as synthetic resin. As shown in FIG. 5, the cover 37 is attached to the housing 36 by, for example, three screws 111 and covers the accommodation opening 85. The screw 111 penetrates the cover 37, for example, and is inserted into a hole opened in the outer surface 82a of the mechanism holding portion 82.

As shown in FIG. 2, the cover 37 is provided with an exposure hole 113, two insertion holes 114, and two positioning holes 115. By inserting the output shaft 43 into the exposure hole 113, the pinion 29 a provided on the output shaft 43 is exposed to the outside of the housing 36 and the cover 37. Two bolts 116 pass through the fixing hole 108 and the insertion hole 114 and are fixed to the arm 25 of FIG. 1, for example. Accordingly, the bolt 116 connects the housing 36 and the cover 37 to the seat 11 of the vehicle 1. The first positioning protrusion 103 and the second positioning protrusion 104 are fitted into the positioning hole 115. As a result, the cover 37 is positioned with respect to the housing 36.

The cover 37 has a coupling portion 121, an engaged claw 122, and an engaged portion 123. The engaged claw 122 and the engaged portion 123 can be respectively referred to as a second engaging portion. The engaged claw 122 may be referred to as a claw. The coupling part 121, the engaged claw 122, and the engaged part 123 are located on one side of the second guide 72 in the third direction D3.

The coupling portion 121 is, for example, a bolt welded to the cover 37. The joining portion 121 is not limited to this example, and may be a portion for joining such as a rivet or a welded portion. The coupling portion 121 is located between the second guide 72A and the engagement protrusion 102 in the circumferential direction of the rotation axis Ax2. The coupling portion 121 is separated from the engagement protrusion 102 and the first positioning protrusion 103. The distance between the coupling portion 121 and the first positioning protrusion 103 is longer than the distance between the coupling portion 121 and the engagement protrusion 102.

The coupling portion 121 floats from the housing 36 in the axial direction of the rotation axis Ax2. In other words, the coupling portion 121 is separated from the housing 36. By separating the coupling part 121 from the housing 36, the degree of freedom in arranging the coupling part 121 is improved. The coupling part 121 is fixed to the arm 25 of FIG. 1, for example. As a result, the joint portion 121 of the cover 37 is joined to the seat 11 of the vehicle 1.

The speed reducer 32 is coupled to the seat 11 by the coupling portion 121 on one side of the second guide 72 in the third direction D3. The speed reducer 32 is coupled to the seat 11 by the bolt 116 on the other side of the second guide 72 in the third direction D3. That is, the housing 36 is not coupled to the seat 11 on one side of the second guide 72 in the third direction D3. The housing 36 is not limited to this example.

The engaged claw 122 is, for example, a part of the cover 37, and is formed by bending. The engaged claw 122 is inserted into the opening 101a of the engaging wall 101. As a result, the engaged claw 122 engages with the engagement wall 101.

The engaged claw 122 is located outside the first wall 101b of the engagement wall 101 in the radial direction of the rotation axis Ax2 and extends along the first wall 101b. The thickness of the engaged claw 122 in the radial direction of the rotation axis Ax2 is smaller than the width of the rotation axis Ax2 in the circumferential direction.

As shown in FIG. 9, the second wall 101c of the engagement wall 101 is located between the engaged claw 122 and the second guide 72B in the circumferential direction of the rotation axis Ax2. The engaged claw 122 is located between the second wall 101c and the third wall 101d in the circumferential direction of the rotation axis Ax2, and faces the second wall 101c and the third wall 101d.

The fourth wall 101e is located outside the engaged claw 122 in the radial direction of the rotation axis Ax2. The engaged claw 122 is located between the first wall 101b and the fourth wall 101e in the radial direction of the rotation axis Ax2.

The engaged claw 122 engages with the engagement wall 101 to limit the deformation of the housing 36 such that the engagement wall 101 moves away from the rotation axis Ax2. The engagement between the engagement wall 101 and the engaged claw 122 will be described in detail below.

For example, a collision may occur in front of the vehicle 1, and a load may act on the seat 11 due to the impact. At this time, a load acts on the stopper plate 64 in the circumferential direction of the rotation shaft Ax3 via the rear link 27, the pinion 29a, the output shaft 43, the internal gear 65, and the external gear 62. As a result, the second guide 72B causes the load Fr1 to act on the inner surface 88a of the second accommodating portion 88.

The load Fr1 acts on the portion 36a of the housing 36 located on one side of the second guide 72B in the third direction D3. The portion 36a includes an inner surface 88a of the second accommodating portion 88 in which the second guide 72B is accommodated, and the engagement wall 101.

The load Fr1 may deform the portion 36a so that the engagement wall 101 moves away from the rotation axis Ax2. In other words, the load Fr1 may deform the portion 36a so that the accommodation opening 85 expands.

When the load Fr1 acts on the portion 36a, the engaged claw 122 supports the first wall 101b of the engaging wall 101 from the outer side in the radial direction of the rotation axis Ax2. Therefore, the engaged claws 122 limit the deformation of the housing 36 such that the engaging wall 101 moves away from the rotation axis Ax2.

Further, when the load Fr1 acts on the portion 36a, the pushed portion 36a moves slightly. For example, the second wall 101c moves away from the rotation axis Ax2 and approaches the engaged claw 122. In addition, the third wall 101d moves away from the rotation axis Ax2 and away from the engaged claw 122. In general, the movement of the second wall 101c and the third wall 101d increases as the position approaches the outer surface 82a of the mechanism holding portion 82 and increases as the position approaches the second guide 72B. Therefore, the portion 36a is deformed so as to be twisted.

The engaged claw 122 supports the moving second wall 101c in the circumferential direction of the rotation axis Ax2. As a result, the engaged claws 122 limit the deformation of the housing 36. Further, the second wall 101c applies a load to the engaged claw 122. However, since the third wall 101d supports the engaged claw 122, deformation of the engaged claw 122 is limited.

In the circumferential direction of the rotation axis Ax2, the engagement wall 101 and the engaged claw 122 are located between the second guide 72B and the first positioning protrusion 103 and the positioning hole 115. Therefore, the load caused by the load Fr1 acts on the engagement wall 101 and the engaged claw 122 more than on the first positioning protrusion 103 and the positioning hole 115. Therefore, the durability of the portion where the first positioning protrusion 103 and the positioning hole 115 fit together is improved.

Further, in the circumferential direction of the rotation axis Ax2, the engagement wall 101 and the engaged claw 122 are located between the second guide 72B and the portion where the cover 37 is attached to the housing 36 by the screw 111. Therefore, the load caused by the load Fr1 acts on the engagement wall 101 and the engaged claw 122 more largely than the mounting portion by the screw 111. For this reason, the durability of the mounting portion by the screw 111 is improved.

As shown in FIG. 2, the engaged portion 123 is, for example, a part of the cover 37. The engaged portion 123 is provided with an opening 123a. The opening 123a is, for example, a substantially circular hole. Further, the engaged portion 123 has an edge 123b that forms (defines) the opening 123a.

The engagement protrusion 102 is fitted into the opening 123a of the engaged portion 123. As a result, the engaged portion 123 engages with the engagement protrusion 102. A part of the edge 123b of the engaged portion 123 is located outside the engagement protrusion 102 in the radial direction of the rotation axis Ax2.

The gap between the engagement protrusion 102 and the edge 123b of the opening 123a is larger than the gap between the first positioning protrusion 103 and the edge of the positioning hole 115, and the gap between the second positioning protrusion 104 and the positioning hole 115 is large. Larger than the gap between the edge. The sizes of the engagement protrusion 102 and the opening 123a are not limited to this example.

The engaged portion 123 engages with the engagement protrusion 102 and limits the deformation of the housing 36 that causes the engagement protrusion 102 to move away from the rotation axis Ax2. The engagement between the engagement protrusion 102 and the engaged portion 123 will be described below in detail.

For example, a collision may occur behind the vehicle 1 and a load may act on the seat 11 due to the impact. At this time, a load acts on the stopper plate 64 in the circumferential direction of the rotation axis Ax3. As a result, as shown in FIG. 7, the second guide 72A causes the load Fr2 to act on the inner surface 88a of the second accommodating portion 88.

The load Fr2 acts on the portion 36b of the housing 36 located on one side of the second guide 72A in the third direction D3. The portion 36b includes an inner surface 88a of the second accommodating portion 88 in which the second guide 72A is accommodated, and the engagement protrusion 102.

The load Fr2 may deform the portion 36b so that the engagement protrusion 102 moves away from the rotation axis Ax2. In other words, the load Fr2 may deform the portion 36b so that the storage opening 85 expands.

When the load Fr2 acts on the portion 36b, the edge 123b of the engaged portion 123 supports the engagement protrusion 102 from the outer side in the radial direction of the rotation axis Ax2. Therefore, the engaged portion 123 limits the deformation of the housing 36 such that the engaging protrusion 102 moves away from the rotation axis Ax2.

In the circumferential direction of the rotation axis Ax2, the engagement projection 102 and the engaged portion 123 are located between the second guide 72A and the first positioning projection 103 and the positioning hole 115. Therefore, the load caused by the load Fr2 acts more on the engaging protrusion 102 and the engaged portion 123 than on the first positioning protrusion 103 and the positioning hole 115. Therefore, the durability of the portion where the first positioning protrusion 103 and the positioning hole 115 fit together is improved.

Further, in the circumferential direction of the rotation axis Ax2, the engagement protrusion 102 and the engaged portion 123 are located between the second guide 72A and the mounting portion with the screw 111. Therefore, the load caused by the load Fr2 acts more on the engaging protrusion 102 and the engaged portion 123 than on the mounting portion by the screw 111. For this reason, the durability of the mounting portion by the screw 111 is improved.

Since the joining portion 121 is joined to the seat 11, a tensile load is generated between the joining portion 121 and, for example, the engaging protrusion 102 and the engaged portion 123. However, in the circumferential direction of the rotation axis Ax2, the engagement protrusion 102 and the engaged portion 123 are separated from the coupling portion 121. Therefore, the load can be dispersed between the engaging projection 102 and the engaged portion 123 and the coupling portion 121.

Furthermore, in the circumferential direction of the rotation axis Ax2, the first positioning protrusion 103 and the positioning hole 115 are farther from the coupling portion 121 than the engagement protrusion 102 and the engaged portion 123. As a result, the load acts on the engaging protrusion 102 and the engaged portion 123 more than on the first positioning protrusion 103 and the positioning hole 115. Therefore, the durability of the portion where the first positioning protrusion 103 and the positioning hole 115 fit together is improved.

The engagement protrusion 102 and the engaged portion 123 are located outside the coupling portion 121 in the radial direction of the rotation axis Ax2. Therefore, the engagement protrusion 102 and the engaged portion 123 can limit the deformation of the housing 36 that causes the engagement protrusion 102 to move away from the rotation axis Ax2.

The load Fr2 acting on the rear side of the vehicle 1 due to the collision is generally stronger than the load Fr1 acting on the front side of the vehicle 1 due to the collision. In the present embodiment, the load caused by the load Fr1 is input to the engaged pawl 122 as a bending load. On the other hand, the load resulting from the load Fr2 is input to the edge 123b of the engaged portion 123 as a shear load. In this way, the durability of the reduction gear transmission 32 is improved by being designed so that a stronger load acts on the engaged portion 123 having higher durability.

As shown in FIG. 5, in this embodiment, the washer 38 is a wave washer. The washer 38 has three first peaks 38a, three second peaks 38b, and an inner edge 38c. The number of the first peaks 38a and the second peaks 38b is not limited to this example, and may be more than three or less than three.

As shown in FIG. 4, the first crest 38a is the apex of the washer 38 on one side in the axial direction of the rotation axis Ax2. The second crest 38b is the apex of the washer 38 on the other side in the axial direction of the rotation axis Ax2. That is, the washer 38 forms three vertices (first peaks 38a) on one side in the axial direction of the rotation axis Ax2 and three vertices (second peaks 38b) on the other side in the axial direction of the rotation axis Ax2. Is formed into a corrugated shape.

As shown in FIG. 4, the washer 38 is interposed between the bottom surface 87b of the first housing portion 87 and the worm wheel 52 of the rotation transmission mechanism 35. The first crest 38 a contacts the support protrusion 52 d of the worm wheel 52. The second crest 38b contacts the bottom surface 87b of the first accommodating portion 87.

The contact area between the washer 38 and the bottom surface 87b of the first accommodating portion 87 is larger than the contact area between the washer 38 and the worm wheel 52. Therefore, even if the worm wheel 52 rotates, the washer 38 does not rotate with respect to the housing 36 and is maintained at substantially the same position.

A part of the output shaft 43, the worm wheel 52, the eccentric shaft 61, and the internal gear 65 are located between the cover 37 and the washer 38. The washer 38 elastically pushes a part of the output shaft 43, the worm wheel 52, the eccentric shaft 61, and the internal gear 65 toward the cover 37. As a result, for example, the output shaft 43 and the internal gear 65 are pressed against the cover 37, and the rotation transmission mechanism 35 is prevented from making an abnormal noise. The washer 38 may push other components of the rotation transmission mechanism 35 toward the cover 37.

FIG. 10 is an exemplary perspective view schematically showing the housing 36 and the washer 38 of the first embodiment. As shown in FIG. 10, the washer 38 is located between the first support portion 91 and the inner surface 87a of the first accommodating portion 87 in the circumferential direction of the rotation axis Ax2. The inner surface 87 a of the first accommodating portion 87 is separated from the washer 38.

The inner edge 38c is an inner edge of the washer 38 in the radial direction of the rotation axis Ax2. Therefore, the inner edge 38c faces inward in the radial direction of the rotation axis Ax2. Further, the inner edge 38c faces the output shaft 43 through the gap.

The first support portion 91 is interposed between the inner edge 38c of the washer 38 and the output shaft 43. The inner edge 38c of the washer 38 can be supported by the first support portion 91 at a position separated from the output shaft 43. In other words, the first support portion 91 restricts the washer 38 from approaching the output shaft 43.

In the speed reducer 32 according to the first embodiment described above, the second guide 72 of the stopper plate 64 projects from the first guide 71 in the second direction D2 orthogonal to the axial direction of the rotation axis Ax2. .. The second housing portion 88 houses the second guide 72, and the inner surface 88a of the second housing portion 88 limits the relative rotation of the housing 36 and the stopper plate 64. That is, when the stopper plate 64 tries to rotate with respect to the housing 36, the second guide 72 comes into contact with the inner surface 88 a of the second housing portion 88, and the inner surface 88 a of the second housing portion 88 has the rotation axis Ax2. The loads Fr1 and Fr2 are input in the circumferential direction of. Further, the coupling portion 121 of the cover 37 is located on one side of a third direction D3 that is orthogonal to the axial direction of the rotation axis Ax2 with respect to the second guide 72 and orthogonal to the second direction D2, and the housing 36. And is coupled to the seat 11 of the vehicle 1. Therefore, the housing 36 is not directly coupled to the seat 11 on one side of the third direction D3 with respect to the second guide 72, and is free with respect to the seat 11. When the loads Fr1 and Fr2 are input, the portions 36a and 36b of the housing 36 on the one side of the third direction D3 with respect to the second guide 72 may be deformed away from the rotation axis Ax2.

In the present embodiment, the housing 36 has the engagement wall 101 and the engagement protrusion 102 that are located on one side of the second guide 72 in the third direction D3. Further, the cover 37 engages with the engagement wall 101 and the engagement protrusion 102 to limit the deformation of the housing 36 such that the engagement wall 101 and the engagement protrusion 102 move away from the rotation axis Ax2. 122 and an engaged portion 123. As a result, the portions 36a and 36b of the housing 36 on one side of the second guide 72 in the third direction D3 move away from the rotation axis Ax2 even when the loads Fr1 and Fr2 are input from the second guide 72. It is suppressed from being deformed. That is, the deformation of the housing 36 is suppressed.

The engaged portion 123 is provided with an opening 123a, and the engaging protrusion 102 is fitted in the opening 123a. As a result, the portion 36b of the housing 36 on the one side of the third direction D3 with respect to the second guide 72 is deformed so as to move away from the rotation axis Ax2, as well as deformed so as to approach the rotation axis Ax2 and the rotation axis Ax2. Deformation in the circumferential direction is suppressed. Therefore, the deformation of the housing 36 is suppressed.

The engaged claw 122 is a claw that extends along the first wall 101b of the engagement wall 101. As a result, the reduction gear 32 is prevented from becoming large in the radial direction. Furthermore, the degree of freedom of arrangement of the engagement wall 101 and the engaged claw 122 is improved.

The engagement wall 101 has a second wall 101c located between the engaged claw 122 and the second guide 72B in the circumferential direction of the rotation axis Ax2 and facing the engaged claw 122. The portion 36a of the housing 36 on one side of the third direction D3 with respect to the second guide 72 moves in the circumferential direction when a load Fr1 is input from the second guide 72 in the circumferential direction of the rotation axis Ax2. Transforms into. However, the engaged claw 122 supports the second wall 101c, so that the deformation is suppressed. Therefore, the deformation of the housing 36 is suppressed.

The engaged claw 122 is located between the second wall 101c and the third wall 101d in the circumferential direction of the rotation axis Ax2. The portion 36a of the housing 36 on one side of the third direction D3 with respect to the second guide 72 moves in the circumferential direction when the load Fr1 is input from the second guide 72 in the circumferential direction of the rotation axis Ax2, and It is twisted away from the rotation axis Ax2. Due to the twist, the housing 36 inputs a load to the engaged claw 122. However, since the third wall 101d supports the engaged claw 122, deformation of the engaged claw 122 is suppressed.

The fourth wall 101e is located outside the engaged claw 122 in the radial direction of the rotation axis Ax2, and is connected to the second wall 101c and the third wall 101d. As a result, the first wall 101b, the second wall 101c, the third wall 101d, and the fourth wall 101e are formed in a frame shape, and the rigidity of the engagement wall 101 is improved.

The bush 63 protrudes from the cylindrical portion 63a, which is interposed between the outer peripheral surface 61a of the eccentric shaft 61 and the inner peripheral surface 62i of the external gear 62, to the outer side in the radial direction of the rotating shaft Ax3, and contacts the concave surface 62d. And a first brim portion 63b. The contact area between the bush 63 and the external gear 62 is increased by the first collar portion 63b. As a result, relative rotation between the bush 63 and the external gear 62 is suppressed, and the relative rotation between the eccentric shaft 61 and the external gear 62 is stabilized. Further, the bush 63 is prevented from coming off the insertion hole 62a.

The bush 63 has a second flange portion 63c that projects from the cylindrical portion 63a to the outside in the radial direction of the rotation axis Ax3 and that contacts the convex surface 62e. The contact area between the bush 63 and the external gear 62 is further increased by the second collar portion 63c. As a result, relative rotation between the bush 63 and the external gear 62 is suppressed, and the relative rotation between the eccentric shaft 61 and the external gear 62 is stabilized. Furthermore, since the external gear 62 is held between the first collar portion 63b and the second collar portion 63c, the bush 63 is prevented from coming off the insertion hole 62a.

The external gear 62 has a first flat surface 62b closer to the flat surface 65b than the concave surface 62d. The bush 63 is separated from the internal gear 65. As a result, it is possible to suppress abnormal noise and a reduction in meshing between the outer teeth 62f and the inner teeth 65d due to contact between the bush 63 and the inner gear 65.

The external gear 62 has a second flat surface 62c located on the opposite side of the first flat surface 62b. The distance between the concave surface 62d and the convex surface 62e is equal to the distance between the first plane 62b and the second plane 62c. As a result, the reduction of the thickness of the external gear 62 is suppressed, and the external gear 62 can stably hold the eccentric shaft 61. Further, the concave surface 62d can be formed by, for example, half blanking. Therefore, the distance (depth) between the concave surface 62d and the first flat surface 62b can be easily adjusted according to the thickness of the first collar portion 63b so that the bush 63 is separated from the internal gear 65. ..

The outer peripheral surface 61a has a first portion 61aa which comes into contact with the tubular portion 63a and a second portion 61ab which is separated from the bush 63 in the axial direction of the rotation axis Ax2. The surface roughness of the first portion 61aa is lower than the surface roughness of the second portion 61ab. As a result, wear of the tubular portion 63a is suppressed, and the durability of the bush 63 is improved. Further, the processing for reducing the surface roughness of the second portion 61ab is not necessary, and the increase in the cost of the speed reducer 32 is suppressed.

The inner edge 38c of the washer 38 can be supported by the first support portion 91 at a position separated from the output shaft 43. As a result, the durability of the washer 38 and the abnormal noise due to the friction between the inner edge 38c of the washer 38 and the output shaft 43 are suppressed.

The inner surface 87 a of the first accommodation portion 87 of the accommodation opening 85 is separated from the washer 38. As a result, interference between the inner surface 87a of the first housing portion 87 and the washer 38 that elastically deforms is suppressed.

The second support portion 92 projects from the bottom surface 87b of the first storage portion 87 of the storage opening 85, is separated from the first support portion 91 inward in the radial direction of the rotation axis Ax2, and supports the output shaft 43. That is, the first support portion 91 is located outside of the second support portion 92 that supports the output shaft 43 in the radial direction of the rotation axis Ax2. Further, the washer 38 is separated from the first support portion 91 to the outside in the radial direction of the rotation axis Ax2. As a result, the washer 38 comes into contact with the worm wheel 52 relatively outside in the radial direction of the rotation axis Ax2, and the rotation transmission mechanism 35 can be stably pushed toward the cover 37.

The housing 36 has a rib 93 that projects from the bottom surface 87b of the first housing portion 87, extends in the radial direction of the rotation axis Ax2, and is connected to the first support portion 91 and the second support portion 92. This suppresses the deformation of the first support portion 91 and the second support portion 92.

The washer 38 is a wave washer having three or more first ridges 38a contacting the rotation transmission mechanism 35 and three or more second ridges 38b contacting the bottom surface 87b of the first accommodating portion 87. is there. Thereby, the washer 38 can stably push the rotation transmission mechanism 35 toward the cover 37. Further, since the washer 38 is a wave washer, fluctuations in load are moderate.

The stopper plate 64 has two second guides 72 protruding from the first guide 71 to one side and the other side of a second direction D2 orthogonal to the axial direction of the rotation axis Ax2. In the third direction D3 which is orthogonal to the axial direction of the rotation axis Ax2 and orthogonal to the second direction D2, the center C1 of the second guide 72A is at a position different from the center C2 of the second guide 72B. This prevents the stopper plate 64 from being arranged in the accommodation opening 85 in an incorrect posture in which the sag surface 64a and the burr surface 64b are reversed.

The two second guides 72 have different lengths in the third direction D3. This prevents the stopper plate 64 from being arranged in the accommodation opening 85 in an incorrect posture in which the sag surface 64a and the burr surface 64b are reversed.

The first side edge 72a of the second guide 72A and the first side edge 72a of the second guide 72B are arranged on the same line. However, in the third direction D3, the second side edge 72b of the second guide 72A is at a position different from the second side edge 72b of the second guide 72B. This prevents the stopper plate 64 from being arranged in the accommodation opening 85 in an incorrect posture in which the sag surface 64a and the burr surface 64b are reversed.

The stopper plate 64 includes a sag surface 64a facing the external gear 62, a burr surface 64b on the opposite side of the sag surface 64a and at least a part of which faces the housing 36, and an edge of the sag surface 64a toward the burr surface 64b. It has a depending edge portion 64c that hangs down, and a protruding edge portion 64d that protrudes from the edge of the burr surface 64b in a direction away from the sag surface 64a. The hanging edge portion 64c and the protruding edge portion 64d may be formed by pressing, for example. In this case as well, the burr surface 64b provided with the protruding edge portion 64d does not face the external gear 62 but faces the housing 36, so that the movement of the external gear 62 is prevented from being hindered.

For example, the hanging edge portion 64c of the sag surface 64a may be further chamfered. In this case, for example, the chamfered hanging edge portion 64c can avoid the connecting portion (R portion) between the flange 62g of the external gear 62 and the guide protrusion 62h.

The housing 36 projects toward the axial direction of the rotation axis Ax2 and faces the second guide 72, and the bottom surface 88b of the second housing portion 88 and the second housing portion 88 that projects from the bottom surface 88b of the second housing portion 88 and correspond to the second housing portion 88b. And a protrusion 95 capable of supporting the guide 72. The protruding portion 95 is separated from the protruding edge portion 64d. As a result, the stopper plate 64 is supported by the protruding portion 95, and the protruding edge portion 64d is prevented from interfering with the housing 36.

In the third direction D3, the center of the protruding portion 95 is located at the center of the bottom surface 88b of the second accommodating portion 88. The protruding portion 95 is located at one of the ends of the bottom surface 88b closer to the first accommodation portion 87 in the second direction D2, and farther from the first accommodation portion 87 of both ends of the bottom surface 88b in the second direction D2. Separate from the edge. This prevents the protruding edge portion 64d from interfering with the housing 36, and the protruding portion 95 can support the second guide 72 so as to be movable in the second direction D2.

(Second embodiment)
The second embodiment will be described below with reference to FIG. In the following description of the embodiments, components having the same functions as the components already described are given the same reference numerals as the components already described, and further description may be omitted. Further, a plurality of constituent elements to which the same reference numerals are assigned do not necessarily have common functions and properties, and may have different functions and properties according to each embodiment.

FIG. 11 is an exemplary cross-sectional view schematically showing the speed reducer 32 according to the second embodiment. As shown in FIG. 11, the washer 38 of the second embodiment is a disc spring. Similarly to the first embodiment, the washer 38 of the second embodiment also pushes part of the output shaft 43, the worm wheel 52, the eccentric shaft 61, and the internal gear 65 toward the cover 37 by elasticity.

As in the second embodiment, the washer 38 is not limited to the wave washer of the first embodiment. The washer 38 may be the disc spring of the second embodiment or another washer such as a spring washer.

The shapes, materials, positions, functions, and relationships of the respective parts and portions in the above plurality of embodiments are not limited to those described and shown in the drawings. For example, the worm wheel 52 and the eccentric shaft 61 may be separate parts. The output shaft 43 and the internal gear 65 may be separate parts.

Although the embodiments of the present invention have been illustrated above, the above embodiments and modifications are merely examples, and are not intended to limit the scope of the invention. The above-described embodiment and modified examples can be implemented in various other forms, and various omissions, replacements, combinations, and changes can be made without departing from the spirit of the invention. Further, the configurations and shapes of the embodiments and the modified examples may be partially replaced with each other.

DESCRIPTION OF SYMBOLS 1... Vehicle, 11... Seat, 31... Motor, 32... Reduction gear, 35... Rotation transmission mechanism, 36... Housing, 37... Cover, 38... Washer, 38a... 1st mountain, 38b... 2nd mountain, 38c ... Inner edge, 43... Output shaft, 52... Worm wheel, 61... Eccentric shaft, 61a... Outer peripheral surface, 61aa... First part, 61ab... Second part, 62... External tooth gear, 62a... Insertion hole, 62b... 1st plane, 62c... 2nd plane, 62d... concave surface, 62e... convex surface, 62f... external tooth, 62i... inner peripheral surface, 63... bush, 63a... cylinder part, 63b... 1st collar part, 63c... 2nd collar part, 64... Stopper plate, 64a... Drip surface, 64b... Burr surface, 64c... Hanging edge part, 64d... Projection edge part, 65... Internal gear, 65b... Plane, 65d... Internal tooth, 71... 1st guide, 72, 72A, 72B... 2nd guide, 72a... 1st side edge, 72b... 2nd side edge, 82... Mechanism holding part, 82a... Outer surface, 85... Storage opening, 87... 1 accommodation section, 87a...inner surface, 87b...bottom surface, 88...second accommodation section, 88a...inner surface, 88b...bottom surface, 91...first support section, 92...second support section, 93...rib, 95 ...Projection part, 101...engaging wall, 101a...opening,...101b...first wall, 101c...second wall, 101d...third wall, 101e...fourth wall,102...engaging protrusion, 121 ... coupling part, 122... engaged claw, 123... engaged part, 123a... opening, Ax1, Ax2, Ax3... rotation axis, D1... first direction, D2... second direction, D3... third direction.

Claims (6)

A driven gear that is rotated about the rotation axis by the driving force of the drive mechanism, a first gear that is moved by the driven gear in the circumferential direction of the rotation shaft, and a limiting member that limits rotation of the first gear. A second gear that is rotated about the rotation axis by the first gear,
A housing having an outer surface directed in the axial direction of the rotation shaft, provided with a housing opening for opening the outer surface and housing the rotation transmission mechanism;
A cover attached to the housing and covering the accommodation opening;
Equipped with,
A first guide that allows the first gear to move in a first direction orthogonal to the axial direction and limits relative rotation of the limiting member and the first gear; A second guide projecting from the first guide in a second direction orthogonal to the axial direction and different from the first direction,
The accommodation opening includes a first accommodation portion in which the driven gear, the first gear, the second gear, and the first guide are accommodated, and a second direction from the first accommodation portion. A second accommodating portion that accommodates the second guide such that the limiting member is movable in the second direction.
The housing is orthogonal to the inner surface of the second accommodating portion that restricts relative rotation of the housing and the restricting member and the axial direction with respect to the second guide, and is orthogonal to the second direction. A first engaging portion located on one side in a third direction to
The cover is located on the one side in the third direction with respect to the second guide, is separated from the housing, and is connectable to a vehicle seat, and the cover is provided with respect to the second guide. Is located on the one side in the third direction, engages with the first engaging portion, and limits deformation of the housing such that the first engaging portion moves away from the rotating shaft. A second engaging portion,
Reduction gear. An opening is provided in one of the first engaging portion and the second engaging portion,
The other of the first engaging portion and the second engaging portion has a protrusion fitted in the opening,
The speed reducer according to claim 1. The first engagement portion has a first wall,
The second engagement portion has a pawl that is located outside the first wall in the radial direction of the rotary shaft and extends along the first wall.
The speed reducer according to claim 1. The speed reducer according to claim 3, wherein the first engagement portion has a second wall that is located between the claw and the second guide in the circumferential direction and faces the claw. The first engaging portion has a third wall facing the claw,
The claw is located between the second wall and the third wall in the circumferential direction,
The speed reducer according to claim 4. The said 1st engaging part is located in the radial direction outer side of the said rotating shaft rather than the said claw, and has a 4th wall connected to the said 2nd wall and the said 3rd wall. 5 speed reducer.

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