JP2001271846A - Rotatory driving force transmission structure and motor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong the service life of a rubber body for buffering transmitted rotatory driving force. SOLUTION: Each damper part 25 of a rubber damper 14 is supported in the circumferential direction of a rotation axis between a side face 23a of an engaging part 23, provided at a damper accommodating part 22 for accommodating the rubber damper 14, and a side face 29a of an engaging projecting part 29 provided at an output plate 15. A space part 27 for allowing the elastic deformation of the damper part 25 is provided on the inner side face 25c side of each damper part 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for transmitting a rotational driving force in a motor device used for, for example, a power window device of a vehicle, and a motor device provided with the structure for transmitting the rotational driving force.

[0002]

2. Description of the Related Art Conventionally, for example, in a motor device of a power window device for opening and closing a side glass for a vehicle, a worm fixed to an output shaft (not shown) of a motor body 50 drives a worm wheel 51 as shown in FIG. The worm wheel 51 is connected to an output plate 53 via a rubber damper 52.
And the output shaft 54 is rotationally driven.

[0003] The worm wheel 51 to which the rotation is transmitted via the rubber damper 52 and the output plate 53 are arranged on the same rotation axis. The rubber damper 52 is accommodated in an annular damper accommodating portion 55 formed inside the worm wheel 51, and is held in the rotation axis direction by the bottom plate portion of the worm wheel 51 and the output plate 53.

The rubber damper 52 comprises a plurality of fan-shaped damper portions 56. Each of the damper portions 56 has a fan-shaped space defined by a plurality of engaging portions 57 provided in the damper accommodating portion 55 and a plurality of engaging convex portions 58 provided on the output plate 53. Are located. That is,
As shown in FIG. 8, each damper portion 56 is sandwiched in the same circumferential direction between the side surface 57a of the engaging portion 57 and the side surface 58a of the engaging convex portion 58 adjacent in the circumferential direction of the rotation axis. It is interposed between the worm wheel 51 and the output plate 53 so as to be supported.

When the side glass rises due to the rotation of the motor 50 and the side glass hits the window frame and the rise is regulated, the rotation of the output plate 53 is regulated and the worm wheel 51 is moved through the respective damper portions 56. Rotation is regulated. At this time, as shown in FIG. 9, each damper portion 56 is elastically deformed by being compressed in the same circumferential direction by a large rotational driving force applied in the circumferential direction of the rotation axis and expanded in the radial direction. For this reason, the force for stopping the motor 50 is absorbed by each damper section 56, and the shock generated in the motor 50 is buffered.

[0006]

However, in the above-described motor device, each of the damper sections 5 is used at an early stage during use.
In some cases, cracks occurred in No. 6 and the shape could not be restored. Then, the dampers 56 did not sufficiently absorb the driving force, and the shock was not sufficiently buffered.

[0007] This is the outer inner peripheral surface 5 of the damper accommodating portion 55.
It is considered that this is because the respective damper portions 56 are radially supported by the 5a and the inner inner peripheral surface 55b, and cannot be elastically deformed by the respective damper portions 56 being sufficiently expanded in the radial direction. . In other words, when the elastic deformation in the radial direction of each damper portion 56 is restricted by the outer inner peripheral surface 55a and the inner inner peripheral surface 55b, the respective surfaces 55a, 55
b, a radial reaction force is applied to each damper portion 56. For this reason, it is considered that the stress generated in each of the damper portions 56 by the elastic deformation due to the rotational driving force increases by that much, and the elastic deterioration of each of the damper portions 56 is promoted. As a result, it is considered that the life of each damper portion 56 has been shortened.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to transmit a rotational driving force capable of prolonging the life of a rubber member that buffers the transmitted rotational driving force. An object of the present invention is to provide a motor device having a structure and a structure for transmitting the rotational driving force.

[0009]

According to a first aspect of the present invention, an output-side rotator is arranged on the same rotation axis with respect to an input-side rotator driven to rotate.
The input support surface provided on the input rotary body and the output support surface provided on the output rotary body are connected to the output rotary body via the rubber body supported in the circumferential direction with respect to the rotation axis. In a rotational driving force transmission structure for transmitting a rotational driving force to a body, at least one of an outer peripheral side and an inner peripheral side of the rubber body with respect to the rotation axis is provided with a space that allows elastic deformation of the rubber body. This is a transmission structure for rotational driving force.

According to a second aspect of the present invention, there is provided a motor body,
An input-side rotator driven by the motor body, an output-side rotator disposed on the same rotation axis as the input-side rotator, an input-side support surface provided on the input-side rotator, A rubber body supported in the circumferential direction between the output-side support surface provided on the output-side rotating body and a rubber body, wherein at least one of an outer circumferential side and an inner circumferential side of the rubber body with respect to the rotation axis. Is a motor device provided with a space that allows elastic deformation of the rubber body.

According to a third aspect of the present invention, in the second aspect of the present invention, the rubber body is sandwiched between the input side support surface and the output side support surface in the circumferential direction with respect to the rotation axis. And the space portion is provided at a position deviating from the region in the radial direction with respect to the rotation axis.

According to a fourth aspect of the present invention, in the third aspect, the input-side support surface and the output-side support surface are formed so as to be substantially perpendicular to the rotation axis in the circumferential direction. It is characterized by being.

(Operation) According to the first aspect of the present invention,
When the rotation of the output-side rotator is restricted while the input-side rotator is being driven to rotate, the rotation of the output-side rotator is larger in the circumferential direction than the rubber body interposed between the input-side engagement portion and the output-side engagement portion. A rotational driving force is applied. Then, the rubber body tends to be elastically deformed by being compressed in the circumferential direction with respect to the rotation axis and expanded in the radial direction. At this time, the rubber body is elastically deformed so as to be sufficiently expanded in the radial direction by the space provided on the outer peripheral side or the inner peripheral side. For this reason, an increase in stress due to the limitation of sufficient elastic deformation in the radial direction is suppressed. Therefore, the stress generated in the rubber body due to the rotational driving force to be absorbed is suppressed, and the characteristic deterioration of the rubber body is not promoted.

According to the second aspect of the present invention, in the motor device for outputting the rotational driving force of the motor to the output side rotating member via the rubber member, the stress generated in the rubber member by the rotational driving force to be absorbed. Is suppressed, and deterioration of the characteristics of the rubber body is not promoted.

According to the invention described in claim 3, according to claim 2
In addition to the effect of the invention described in (1), the stress due to the rotational driving force is generated by being dispersed over the entire rubber body existing in the region. Therefore, the concentration of the stress generated in the rubber body due to the rotational driving force is suppressed, and the deterioration of the characteristics of the rubber body due to the stress concentration is hardly promoted.

According to the invention set forth in claim 4, according to claim 3,
In addition to the effect of the invention described in (1), since a radial force is hardly applied to the rubber body from each support surface, the rubber body is hardly bent in the radial direction by the radial force. Thus, the space only needs to allow the rubber body to expand radially due to circumferential forces.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment in which the present invention is embodied in a motor device of a power window device for a vehicle.
4 will be described with reference to FIG.

As shown in FIG. 1, the motor device 1 includes a motor body 10 and a speed reduction unit 11. Motor body 10
Has an output shaft (not shown) extending toward the speed reduction unit 11. The speed reduction unit 11 includes a housing 12, a worm wheel 13 as an input-side rotating body, a rubber damper 14, an output plate 15 as an output-side rotating body, an output shaft 16, a lid 17, and the like.

The housing 12 is integrally formed of a synthetic resin and includes a motor fixing portion 12a, a worm housing 12b, and a wheel housing 12c. Motor fixing part 12a
, The motor main body 10 is fixed, and its output shaft extends inside the worm housing portion 12b. A worm gear (not shown) is fixed to the output shaft, and a part of the worm gear is disposed in the wheel housing 12c.

The wheel accommodating portion 12c is formed in a substantially cylindrical shape having a bottom, and a cylindrical shaft support portion 18 is formed at the center of the upper surface of the bottom plate portion. The shaft support 18 has a shaft hole 18a extending in the axial direction. A plurality of convex support portions 19 are formed at equal angular intervals along the circumference of a circle centered on the central axis of the shaft hole 18a on the upper surface of the bottom plate portion of the wheel accommodating portion 12c. The convex support 19 is formed to support the worm wheel 13. The worm wheel 13 is provided in the wheel housing 12c.
Is housed.

The worm wheel 13 is integrally formed of a synthetic resin into a substantially cylindrical shape with a bottom, and a gear portion 20 meshed with the worm gear is formed on the outer peripheral surface thereof. A shaft hole 21 through which the shaft support 18 can be inserted is formed in the center of the worm wheel 13. An annular damper housing 22 for housing the rubber damper 14 is provided between the gear 20 and the shaft hole 21. The damper accommodating portion 22 has a disk-shaped bottom plate upper surface 22 a centered on the central axis of the shaft hole 21, and a cylindrical outer inner peripheral surface 22.
b and the inner peripheral surface 22c formed in the same cylindrical shape.

Three engaging portions 23 are formed on the upper surface 22a of the bottom plate portion of the damper accommodating portion 22. Each engagement part 23
Are provided at equal angular intervals, and are formed to extend from the outer inner peripheral surface 22b in the radial direction to near the inner inner peripheral surface 22c. Each engagement portion 23 has a side surface 23a as an input-side support surface that is substantially orthogonal to the central axis of the shaft hole 21 in the circumferential direction. Each of the engaging portions 23 has a substantially fan-shaped 3 around the center axis.
Divided into two parts. That is, the damper housing 22 is
Bottom plate upper surface 22a, outer inner peripheral surface 22b, inner inner peripheral surface 22
c and three chambers defined by the side surface 23a. A projection 24 extending along the circumference of a circle centered on the central axis is formed on the bottom plate upper surface 22a of the damper housing 22. And the worm wheel 13
The shaft support portion 18 is inserted through the shaft hole 21, and each convex support portion 19 abuts on the bottom surface of the bottom plate portion.
Are rotatably accommodated in the wheel accommodating portion 12c while meshing with the worm gear. That is, the worm wheel 13 is rotatably supported with the respective central axes of the shaft support 18 and the shaft hole 21 as its rotation axes. The rubber damper 14 is housed in the damper housing 22.

The rubber damper 14 is integrally formed in an annular shape,
A damper portion 25 is formed as a shape obtained by dividing the annular plate material in the radial direction, that is, six rubber bodies formed in a substantially fan shape. Each of the damper portions 25 is annularly connected by a connecting portion 26 on the inner peripheral side. Each damper part 25 is formed in the same shape with the same thickness, and has a side surface 25 a that is substantially perpendicular to the central axis of the rubber damper 14 in the circumferential direction. As shown in FIG. 2, the outer surface 25b of each damper part 25 formed on the cylinder centering on the center axis of the rubber damper 14 has the outermost diameter R1. That is, as shown in FIG. 3, the rubber damper 14 is configured such that the outer surface 25 b of each damper portion 25 is formed on the outer inner peripheral surface 22 b of the damper housing 22.
It is formed in a size that is substantially inscribed in.

In the rubber damper 14, the inner surface of each connecting portion 26 on a cylinder centered on the central axis is formed with the innermost diameter R.
It is 2. That is, the rubber damper 14 is connected to each connecting portion 2.
6 is formed to a size that circumscribes the inner peripheral surface 22 c of the damper housing 22. Also, each damper part 25
The inner side surface 25c is formed so as to be recessed toward the outer peripheral side from the innermost diameter R2. That is, the rubber damper 14 is formed so that the inner side surface 25c of each damper part 25 does not contact the inner side inner peripheral surface 22c.

Then, as shown in FIG. 3, the rubber damper 14 has two adjacent
The side surfaces 2 of both damper portions 25 are accommodated in the respective chambers defined by
5a is accommodated in the damper accommodating portion 22 in a state of being fitted in the gap between them. At this time, each damper portion 25 is accommodated in a state where there is almost no gap between the outer inner peripheral surface 22b of the damper accommodating portion 22 and the outer surface 25b, and between the inner inner peripheral surface 22c and the inner side surface 25c. It is housed in a state of forming a semilunar space 27. Further, the rubber damper 14 is provided with each damper part 25.
Are supported so as not to contact the upper surface 22a of the bottom plate portion by the projections 24 of the damper accommodating portion 22 abutting substantially at the center in the radial direction. The output plate 15 is disposed above the rubber damper 14.

As shown in FIG. 1, the output plate 15 is formed of a metal plate in a substantially disk shape, and a shaft fitting portion 28 to which the output shaft 16 is fixed is formed at the center. Output plate 1
On the lower surface 15a of the fifth 5, three engagement projections 29 are formed. The engaging projections 29 are provided at regular angular intervals and are formed to extend in the radial direction with respect to the central axis. Each engagement projection 29 includes a side surface 29 a as an output-side support surface that is substantially perpendicular to the center axis of the output plate 15 in the circumferential direction, and is fitted into a gap between the side surfaces 25 a of the adjacent damper portions 25. Is formed. The output plate 15 is accommodated in the worm wheel 13 in a state where the respective engaging projections 29 are fitted in the gaps between the side surfaces 25a of the corresponding damper portions 25.

As shown in FIG. 3, each of the damper portions 25 is sandwiched between the side surfaces 23a and 29a of the engaging portion 23 and the engaging convex portion 29 which are circumferentially adjacent to the rotation axis. It is supported in the circumferential direction. More specifically, each of the damper portions 25 is provided with a side surface 23 a of the engagement portion 23 and an engagement protrusion 29.
The fan-shaped region D sandwiched in the circumferential direction with respect to the rotation axis between the side surface 29a and the side surface 29a, that is, an annular region having a radius from the innermost side to the outermost side of the side surface 23a and the side surface 29a,
Fan-shaped area D defined by both side surfaces 23a and 27a
Is provided to exist. That is, each damper unit 2
When a force that compresses in the circumferential direction from the side surface 23 a of the engaging portion 23 and the side surface 29 a of the engaging convex portion 29 is applied to the portion 5, stress is mainly applied to the damper portion 25 existing in this region D. Are concentrated and a circumferential reaction force is generated. The space portion 27 is provided at a position deviated from the region D toward the radially inner peripheral side. And the space 27
When a circumferential force is applied to the damper portion 25,
The elastic deformation caused by the radial inward expansion of the damper portion 25 is allowed. Also, the shaft fitting portion 28 of the output plate 15
The output shaft 16 is fitted through a shaft hole 18 a of the shaft support 18.

As shown in FIG. 1, the output shaft 16 has a fitting portion 32 fitted to the shaft fitting portion 28 at the upper end of the shaft portion 31.
And a gear portion 33 below the shaft portion 31. The gear portion 33 is meshed with a drive-side gear portion of a window regulator (not shown). The output shaft 16 has the shaft portion 31 rotatably penetrated through the shaft hole 18 a of the shaft support portion 18, and the fitting portion 32 is fitted to the shaft fitting portion 28 of the output plate 15 so as to be integrally rotatable. In this state, it is supported by the wheel housing 12c. The output shaft 16 is connected to the shaft fitting portion 28 and the shaft hole 18 by an E-ring 34 engaged with an engagement groove 32 a provided at an upper end of the fitting portion 32 projecting upward from the shaft fitting portion 28.
It is fixed so as not to fall out from a. The output shaft 16
An O-ring 35 is provided between the shaft portion 31 and the gear portion 33 to seal the space between the shaft portion 31 and the shaft hole 18a.

The lid 17 is fixed to the housing 12 while covering the upper opening of the wheel accommodating portion 12c. Next, the operation of the motor device configured as described above will be described.

When the side glass hits the window frame and its movement is regulated while the side glass is raised, the operation of the output shaft 16 and the output plate 15 is regulated via the window regulator. At this time, the circumferential force applied to each damper portion 25 pressed against each engagement protrusion 29 of the output plate 15 by each engagement portion 23 of the worm wheel 13 sharply increases. Then, each damper part 25 is elastically deformed so as to be compressed in the circumferential direction and expanded in the rotation axis direction.

At this time, as shown in FIG. 4, each of the damper portions 25 has a space 2 provided on the inner side surface 25c thereof.
7, it is elastically deformed by expanding inward in the radial direction. For this reason, an increase in stress due to the limitation of sufficient elastic deformation in the radial direction is suppressed. Therefore, the stress generated by the rotational driving force to be absorbed is suppressed, and the deterioration of the characteristics of the rubber body is not promoted.

Each of the damper portions 25 is provided in a fan-shaped region D sandwiched between the side surface 23a of the engaging portion 23 and the side surface 29a of the engaging convex portion 29 in the circumferential direction with respect to the rotation axis, The space 27 is provided at a position outside the area D.
For this reason, stress is dispersed and generated over the entire portion of the damper portion 25 existing in the region D. Therefore, the concentration of the stress generated in the damper portion 25 is suppressed, and the characteristic deterioration of the damper portion 25 is not easily promoted.

According to the above-described embodiment, the following effects can be obtained. (1) In the present embodiment, each damper part 25 of the rubber damper 14 housed in the damper housing part 22 is sandwiched between the side surface 23a of the engaging part 23 and the side surface 29a of the engaging convex part 29 in the circumferential direction of the rotation axis. To support. A space 27 is provided on the inner peripheral side of each of the damper portions 25 to allow elastic deformation of the damper portion 25 in the radial direction. Therefore, the stress generated by the rotational driving force is suppressed, and the characteristic deterioration of each damper portion 25 is not easily promoted, so that the life of the rubber damper 14 can be further extended.

(2) In addition, in this embodiment, each damper portion 25 is sandwiched between the side surface 23a of the engaging portion 23 and the side surface 29a of the engaging convex portion 29 in the circumferential direction with respect to the rotation axis. It was provided so as to include the fan-shaped region D, and the space portion 27 was provided at a position on the inner peripheral side outside the region D. Therefore, the concentration of the stress generated in each damper section 25 due to the rotational driving force is suppressed, and the characteristic deterioration of each damper section 25 due to the stress concentration is hardly promoted, so that the life of the rubber damper 14 can be further extended.

(3) In addition, in this embodiment, the engaging portion 2
The third side surface 23a and the side surface 29a of the engaging projection 29 are formed so as to be substantially perpendicular to the rotation axis in the circumferential direction. For this reason, a radial force is not easily applied to the damper portion 25 from each of the side surfaces 23a and 29a, and the damper portion 25 is unlikely to bend toward the space portion 27 due to the radial force. Therefore, the space portion 27 only needs to allow the damper portion 25 to expand in the radial direction due to the circumferential force, so that the volume of the space portion 27 can be smaller and the transmission mechanism does not become large. .

Hereinafter, embodiments of the invention other than the above-described embodiment will be listed as other examples. In the above embodiment, the inner surface 25c of each damper part 25
5, the outer surface 25b of each damper portion 25 is formed in a shape recessed toward the rotation shaft, as shown in FIG.
A space section 40 may be formed between the space section b. Also in this case, the stress generated by the rotational driving force to be absorbed is suppressed, and the characteristic deterioration of each damper section 25 is not easily promoted, so that the life of the rubber damper 14 can be further extended.

In the above embodiment, the space portion 27 is formed by denting the inner surface 25 c of each damper portion 25 of the rubber damper 14 toward the outer peripheral side with respect to the inner inner peripheral surface 22 c of the damper housing 22. This is applied to the inner surface 2 of each damper part 25.
5c is formed on the same cylinder together with the inner surface of each connecting portion 26, and a concave portion is newly provided on the inner inner peripheral surface 22c for each damper portion 25, thereby forming a space on the inner surface 25c side of the damper portion 25. It may be formed.

Similarly, a space may be formed on the outer peripheral side of the damper section 25 by providing a concave portion on the outer inner peripheral surface 22b of the damper accommodating section 22 for each damper section 25. In the above embodiment, the rubber damper 1 in which the inner surface of each connecting portion 26 circumscribes the inner inner peripheral surface 22 c of the damper housing 22.
4, the inner surface 25c of each damper portion 25 is recessed from the inner inner peripheral surface 22c to the outer peripheral side, thereby forming the space portion 27.
Was formed. This is applied to each damper section 2 as shown in FIG.
5 are made independent from each other without providing each connecting portion 26. Then, an annular space portion 4 is provided on the inner side surface 25c side of each damper portion 25.
1 may be formed. Also in this case, the stress generated by the rotational driving force to be absorbed is suppressed, and the characteristic deterioration of each damper section 25 is not easily promoted, so that the life of the rubber damper 14 can be further extended.

In the above embodiment, the space 27 is provided only on the inner surface 25c side of each damper portion 25.
A space may be provided on each of the 5b side and the inner surface 25c side.

In the above embodiment, the present invention is applied to the transmission structure of the rotational driving force in the motor device 1 of the vehicle power window device. However, the present invention is applied to other motor devices such as the vehicle power door opening / closing device and the power roof opening / closing device. Is also good.

Hereinafter, the technical ideas grasped from each of the above embodiments will be described together with their effects. (1) In the invention described in claim 1, the rubber body is at least present in a region sandwiched between the input-side support surface and the output-side support surface in the circumferential direction with respect to the rotation axis. The space is provided, and the space is provided at a position deviated from the region in the radial direction with respect to the rotation axis. According to such a configuration, the stress generated in the rubber body due to the rotational driving force is suppressed, and the characteristic deterioration of the rubber body is not easily promoted, so that the life of the rubber body can be further extended.

(2) In the invention described in the above (1), the input-side support surface and the output-side support surface have a rotational driving force that is formed so as to be substantially perpendicular to the rotation axis in the circumferential direction. Transmission structure. According to such a configuration, since the volume of the space portion can be smaller, downsizing can be achieved.

[0043]

According to the first to fourth aspects of the present invention, the stress generated by the rotational driving force on the rubber member that buffers the transmitted rotational driving force is suppressed, and the characteristic deterioration of the rubber member is not promoted. The life of the rubber body can be prolonged.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a motor device according to an embodiment.

FIG. 2A is a plan view of a rubber damper, and FIG. 2B is a cross-sectional view taken along line AA in FIG.

FIG. 3 is a plan view showing a rubber damper and a worm wheel.

FIG. 4 is a plan view showing a rubber damper and a worm wheel in an operating state.

FIG. 5 is a plan view of a rubber damper and a worm wheel according to another embodiment.

FIG. 6 is a plan view of a rubber damper and a worm wheel according to another embodiment.

FIG. 7 is an exploded perspective view showing a conventional motor device.

FIG. 8 is a plan view showing a rubber damper and a worm wheel.

FIG. 9 is a plan view showing the rubber damper and the worm wheel in an operating state.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Motor apparatus, 10 ... Motor main body, 13 ... Worm wheel as an input side rotating body, 15 ... Output plate as an output side rotating body, 23a ... Side surface as an input side support surface, 25
... A damper part as a rubber body, 27 ... Space part, 29a ... Side side as an output side support surface, D ... Area.

Claims (4)

[Claims] An output side rotating body (15) is arranged on the same rotation axis with respect to an input side rotating body (13) driven to rotate, and an input support surface (15) provided on the input side rotating body (13). 23
a) and an output-side support surface (29a) provided on the output-side rotator (15) through a rubber member (25) supported in a circumferential direction with respect to the rotation axis from the input-side rotator (13) to the output side. In a rotational driving force transmitting structure for transmitting a rotational driving force to a rotating body (15), at least one of an outer peripheral side and an inner peripheral side of the rubber body (25) with respect to the rotation axis line includes the rubber body (25). A rotational driving force transmission structure, comprising a space (27) that allows elastic deformation. 2. A motor body (10a), an input-side rotating body (13) driven to rotate by the motor body (10a), and an output arranged on the same rotation axis as the input-side rotating body (13). Between the input-side rotator (15) and the input-side support surface (23a) provided on the input-side rotator (13) and the output-side support surface (29a) provided on the output-side rotator (15). And a rubber body (25) supported in the circumferential direction by a rubber body (25), wherein at least one of the outer circumference side and the inner circumference side of the rubber body (25) with respect to the rotation axis is provided with the rubber body (25). A motor device provided with a space portion (27) that allows elastic deformation. 3. The rubber body (25) is located in a region (D) sandwiched between the input side support surface (23a) and the output side support surface (29a) in the circumferential direction with respect to the rotation axis. The space (27) is provided so as to exist at least.
The motor device according to claim 2, wherein the region (D) is provided at a position radially deviated from the rotation axis. 4. The motor device according to claim 3, wherein the input-side support surface (23a) and the output-side support surface (29a) are formed so as to be substantially perpendicular to the rotation axis in the circumferential direction.