KR20020003816A - Rotary damper and assist grip device - Google Patents

Abstract

PURPOSE: To provide a rotary damper for simply and easily performing assembling work and capable of simply and easily changing torque. CONSTITUTION: This rotary damper is composed of a housing 11 arranging a shaft support hole 12a at the bottom 12 and having the opening ceiling, a rotor 21 inserted into this housing 11, having one end rotatably supported by the peripheral edge of the shaft support hole 12a, arranging an inserting hole 22a communicating with the shaft support hole 12a and integrally arranged with a flange 26 for blocking up the ceiling of the housing 11 and an O ring 31 arranged on the outer periphery of the rotor 21, brought into pressure contact with the inner periphery of the housing 11 and generating frictional resistance between the inner periphery of the housing 11 and the outer periphery of the rotor 21, and a torque changing means (a cam projecting part 13b and a cam surface 24) for changing the torque is arranged in the housing 11 and the rotor 21.

Description

Rotary damper and assist grip device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a housing that rotates and rotates relatively by the frictional resistance of a housing and a friction body or a rotor and a friction body, or a rotary damper that brakes rotation and rotation of a rotor and an assist grip device using the rotary damper.

Conventional rotary dampers are, for example, a cylindrical housing having a bottom and a ceiling opening in order to brake the rotation and rotation of the housing relatively rotating and rotating by the viscous resistance of a viscous fluid such as silicone oil or the like. and; A rotor inserted into the housing so that an outer circumferential surface of the housing faces the inner circumferential surface at a predetermined interval; A cap which closes the ceiling of the housing and rotatably supports a part of the rotor; A sealing member installed in the housing to seal between the rotor and the cap; It consists of a viscous fluid filled in the filling portion formed by the housing, the rotor, the cap and the sealing member.

The conventional rotary damper is composed of five parts of a housing, a rotor, a cap, a sealing member, and a viscous fluid, and the assembly work is required because the viscous fluid should be filled in the live part and the housing and the cap should be welded and sealed. This is troublesome.

The torque can be changed by changing the viscous fluid, but there is a problem that the torque cannot be changed after assembly.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a rotary damper and an assist grip device using the rotary damper can easily and easily change the assembling work and also change the torque. To provide.

1 is a front sectional view showing a rotary damper according to a first embodiment of the present invention.

2 is an exploded perspective view of the rotary damper shown in FIG.

3 is a plan view of the housing shown in FIG.

4 is an enlarged cross-sectional view of the rotor corresponding to the X-X ray of FIG.

5 is an explanatory diagram showing a change in torque

6 is a perspective view of a rotor and a rubber bush used in the rotary damper according to the second embodiment of the present invention.

Fig. 7A is a perspective view of a rotor and a friction body used in the rotary damper according to the third embodiment of the present invention, and Fig. 7B is a front view of a part thereof broken away.

8 is an exploded perspective view in which part of the assist grip device according to the present invention is omitted.

Explanation of symbols on the main parts of the drawings

D-Rotary Damper 11-Housing

12-bottom 12a-shaft support holes

13-perimeter wall 13a-stone

13b-cam projection 21-rotor

22-Shaft 22a-Through Hole

23-stone 24-cam face

24a-circular arc 24b-first undulating surface

24c-circular arc 24d-second relief plane

25-engaging protrusion 26-flange

26a-fitting step 31-O-ring

31A-Rubber Bush 31B-Rib

32-Through Hole A-Assist Grip Device

61A, 61B-Bracket 62-Attachment

62a-mounting hole 63-support piece

63a-shaft support hole 63b-groove

71-Torsion Spring 81-Assist Grip

82-through hole 83-fitting hole

91-support shaft

The rotary damper according to the present invention includes a cylindrical housing having a bottom portion and a ceiling opening; A rotor inserted into the housing; It is provided with an outer circumference of the rotor is pressed against the inner circumference of the housing, the friction body having elasticity for generating a frictional resistance between the inner circumference of the housing or between the outer circumference of the rotor; (Claim 1).

Moreover, the rotation damper which concerns on another invention is the cylindrical housing which the hole is formed in the center of a bottom part, and the ceiling opened; A rotor which is inserted into the housing and has a through hole communicating with a hole in a bottom portion thereof; It is provided with an outer circumference of the rotor is pressed against the inner circumference of the housing, the friction body having elasticity for generating a frictional resistance between the inner circumference of the housing or between the outer circumference of the rotor; (Claim 2).

In addition, a rotary damper according to another invention includes a cylindrical housing in which a shaft support portion and a hole are formed concentrically in the bottom portion, and a ceiling is opened; A rotor inserted into the housing so that one end of the shaft is rotatably supported by the shaft support, the through hole communicating with the hole of the bottom; A cap that closes the ceiling of the housing and rotatably supports the other end of the rotor so that the rotor rotates on the axis of the shaft support; It is installed on the outer circumference of the rotor and pressed against the inner circumference of the housing, and a friction body having elasticity to generate a frictional resistance between the inner circumference of the housing or between the outer circumference of the rotor; Torque fluctuation means for varying the torque by varying the thickness in the radial direction of the friction body in a predetermined range in which the housing and the rotor rotate relatively is formed in the housing and the rotor (claim 3).

The cap may be integrally formed on the rotor so as to rotate with respect to the housing (claim 4), and the friction body may be constituted by one or more O-rings (claim 5).

In the rotary damper of claim 1 or 2, the friction body may be formed integrally with the rotor by a soft synthetic resin (claim 6).

Another invention is an assist grip device for holding a pivotally assisted assist grip in a return position by a holding means, wherein the rotation of the assist grip is braked by the rotary damper according to any one of claims 1 to 6. (Claim 7).

The rotary damper is preferably provided on a support shaft for supporting the assist grip in a rotatable manner (claim 8).

Embodiment of the Invention

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail based on drawing.

(1st embodiment)

1 is a front sectional view showing a rotary damper according to a first embodiment of the present invention, FIG. 2 is an exploded perspective view of the rotary damper shown in FIG. 1, FIG. 3 is a plan view of the housing shown in FIG. It is sectional drawing of the rotor corresponding to the XX line of 1, and FIG. 5 is explanatory drawing which showed the fluctuation | variation of a torque.

In addition, in FIG. 4, the black spot is displayed in the branch position of each surface which forms a cam surface. In addition, in FIG. 5, the circle | round | yen of the dashed-dotted line is shown in order to make clear the ups and downs of each surface which forms a cam surface.

In the above drawings, reference numeral D denotes a rotary damper and has a cylindrical housing 11 having a bottom portion 12 and an open ceiling; A rotor 21 inserted into the housing 11, the rotor 21 partially protruding from the housing 11; Friction is provided on the outer circumference of the rotor 21, the pressure is pressed into the housing 11 to generate a frictional resistance between the inner circumference of the housing 11 or between the outer circumference of the rotor 21 O-ring 31 as a sieve.

The housing 11 is formed of a synthetic resin, a circular bottom portion 12 having a circular shaft support hole 12a in the center; It is formed successively at the peripheral edge of the bottom portion 12, the protrusion 13a is formed on the outside extending to a predetermined height in the axial direction, the inner circumferential surface after gently projecting inward from the inner circumferential surface as shown in FIG. The cam protrusion 13b which returns gently to the cylindrical circumferential wall 13 formed in the axial direction to the vicinity of the ceiling opened from the bottom part 12 is comprised.

In addition, the cam protrusion 13b is formed at the same circumferential position as the protrusion 13a so that the position can be easily seen from the outside.

The shaft support hole 12a also serves as a shaft support portion and a hole.

In addition, the cam protrusion 13b is a part which comprises the torque change means which changes a torque.

The rotor 21 is formed of a synthetic resin, the through hole 22a is formed in the center in the axial direction, the outer end of which is substantially the same as the inner diameter of the shaft support hole 12a (one end) is the shaft support hole 12a. A shaft portion 22 rotatably axially supported by a circumferential edge thereof; The circumferential wall 13 of the circumferential wall 13 which is formed successively on the upper end (the other end) side of the shaft portion 22 and closes the ceiling of the housing 11 in a state where one end of the shaft portion 22 is inserted into the shaft support hole 12a. A flange 26 functioning as a cap having an inner diameter substantially equal to an outer diameter.

And when the shaft part 22 is inserted in the housing 11, the protrusion formed along the outer periphery in the part of the shaft part 22 located in the said housing 11 at a height lower than the outer diameter of the O-ring 31 is carried out. A plurality of 23 pieces is formed along the axial direction. This protrusion 23 functions to determine the position by preventing the o-ring 31 from moving in the axial direction.

In addition, in the shaft part 22 located in the housing 11, the external shape of the part of the shaft part 22 which does not form the said protrusion 23 except for the lower end of the shaft part 22 is formed, FIG. As shown in FIG. 5, the circular arc surface 24a which opposes the inner circumferential surface of the circumferential wall 13 at predetermined intervals, and the radius in this protruding state are projected gently outwardly from this circular arc surface 24a. After the arc surface continues for a predetermined length, the first undulating surface 24b gradually returns to the arc surface 24c having the same radius as the arc surface 24a, and is gently turned off inward from the arc surface 24c. The cam surface 24 which consists of the 2nd undulating surface 24d which returns to circular arc surface 24a is provided.

The cam surface 24 constitutes torque changing means for varying the torque together with the cam protrusion 13b described above, and is arranged side by side in the axial direction.

Further, two engaging projections 25 are formed at the front end (the other end) of the shaft portion 22 protruding from the flange 26 (housing 11) at positions facing each other with respect to the through hole 22a. have.

On the housing 11 side of the flange 26, the outer diameter, which is fitted to the housing 11 and rotates so that the shaft portion 22 rotates on the axis line of the shaft support hole 12a, is almost equal to the inner diameter of the housing 11. The same cylindrical fitting step part 26a is formed.

Moreover, at least one side is chamfered in the part which fits together, such as the inner end of the axial support hole 12a, and the lower end of the axial part 22, in order to make the fitting easy.

Subsequently, the assembly will be described.

First, on the outer circumference of the shaft portion 22, that is, between the flange 26 and the protrusion 23, between the protrusion 23 and the protrusion 23, and also with the lower end of the protrusion 23 and the shaft portion 22. O-ring 31 is attached in between.

Then, each O-ring 31 is press-fitted into the housing 11 while the shaft portion 22 is inserted into the housing 11 from the lower end side thereof, and the lower end of the shaft portion 22 is fitted into the shaft support hole 12. At the same time, the rotation damper D can be assembled in the state shown in FIG. 1 by closing the ceiling (opening) of the housing 11 with the flange 26 while fitting the fitting step 26a into the housing 11.

Subsequently, the operation will be described.

First, when the housing 11 and the rotor 21 rotate relatively with the O-ring 31 interposed, the cam protrusion 13b is provided while the cam protrusion 13b and the circular arc surface 24a face each other. Since the interval between the and the circular arc surface 24a does not change, the torque does not fluctuate (change).

However, when the cam protrusion 13b and the first undulating surface 24b start to face each other, the gap between the cam protrusion 13b and the first undulating surface 24b is gradually narrowed, and then the narrowest interval is continued slightly, Then, since the torque gradually increases, the torque gradually increases, and then the maximum increase continues slightly, and then fluctuates gently to return to the original torque.

And while the cam protrusion 13b and the arc surface 24c oppose, similarly as the cam protrusion 13b and the arc surface 24a oppose, between the cam protrusion 13b and the arc surface 24c. Since the interval does not change, the torque does not change.

However, when the cam protrusion 13b and the second undulating surface 24d start to face each other, the torque is gentle because the gap between the cam protrusion 13b and the second undulating surface 24d gradually widens and then narrows gently. After it becomes small, it changes to return to the original torque.

As described above, according to the rotary damper D according to the first embodiment of the present invention, the O-ring 31 is provided on the outer circumference of the shaft portion 22 (rotor 21), and the shaft portion 22 is provided. Since the rotary damper D can be assembled by inserting the O-ring 31 into the inner circumference of the housing 11 while inserting the {rotor 21} into the housing 11, the assembling operation is simple and easy. Therefore, it is possible to assemble the rotary damper (D) efficiently.

Then, torque is changed by changing the number of O-rings 31 which generate frictional resistance between the inner circumference of the housing 11 or between the outer circumference of the shaft portion 22 (rotor 21). Since it is possible to change, it is possible to easily and easily change the torque.

In addition, since there is no use of a fluid such as a viscous fluid and there is no sealing portion by welding, it is possible to easily and easily change the torque by disassembling even after assembling and changing the number of O-rings 31.

In addition, since the torque changing means for varying the torque is formed, the assist grip is close to the return position, for example, when braking the assist grip axially rotatably supported and supported by the holding means to the return position. Since the holding force of the holding means decreases, the assist grip can be smoothly returned to the return position by reducing the torque when the assist grip approaches the return position.

And since the O-ring 31 which is a general purpose product was used as a friction body, the rotary damper D can be manufactured at low cost.

(2nd embodiment)

6 is a perspective view of a rotor and a rubber bush used in the rotary damper according to the second embodiment of the present invention. In addition, the same code | symbol is attached | subjected about the part same as FIG. 1 thru | or 5, and the description is abbreviate | omitted.

The housing which is not shown in figure has the structure similar to 1st Embodiment.

In Fig. 6, reference numeral 31A denotes a rubber bush having a cylindrical shape as a friction body, and a through hole 32 through which the shaft portion 22 of the rotor 21 is press-fitted is formed at the center thereof.

In addition, the protrusion 23 in 1st Embodiment is not formed in the shaft part 22, and only the cam surface 24 is formed.

Subsequently, the assembly will be described.

In the case of using the rubber bush 31A, first, as in the case of the O-ring 31, first press the shaft portion 22 into the through hole 32 and attach the rubber bush 31A to the outer circumference of the shaft portion 22. do.

Then, the rubber bush 31A is press-fitted into the housing 11 while the shaft portion 22 is inserted into the housing 11 from the lower end side thereof, and the lower end of the shaft portion 22 is fitted into the shaft support hole 12. The rotary damper D can be assembled by closing the ceiling (opening) of the housing 11 with the flange 26 while fitting the fitting step 26a into the housing 11.

In addition, since operation is the same as that of the case where the O-ring 31 is a friction body, the description is abbreviate | omitted.

Also in the rotary damper D which concerns on said 2nd Embodiment, the effect similar to 1st Embodiment can be acquired.

And since the rubber bush 31A is used as a friction body, when manufacturing the high torque rotary damper D, it can manufacture more inexpensively than when using a plurality of O-rings 31. As shown in FIG.

(Third embodiment)

FIG. 7A is a perspective view of a rotor and a friction body used in the rotary damper according to the third embodiment of the present invention, and FIG. 7B is a front view of a portion thereof broken. In addition, the same code | symbol is attached | subjected about the part same as FIG. 1 thru | or 6, and the description is abbreviate | omitted.

Although the housing which is not shown in figure has the structure similar to 1st Embodiment, the cam protrusion 13b is not formed.

In Fig. 7, reference numeral 31B denotes a rib having elasticity as a friction body. The ribs 31B are formed in an umbrella shape that extends toward the flange 26 along the outer periphery of the shaft portion 22, and are formed in plural along the axial direction.

The rib 31B is a soft synthetic resin and is integrally molded to the rotor 21 by a two-color molding method.

In addition, the protrusion 23 and the cam surface 24 in above-mentioned 1st Embodiment are not formed in the shaft part 22. As shown in FIG.

Subsequently, the assembly will be described.

In the case of using the rotor 21 having the ribs 31B formed thereon, each of the ribs 31b is press-fitted into the housing 11 while inserting the shaft portion 22 into the housing 11 from the lower end side thereof. 22, the lower end of the housing 11 is fitted with the shaft support hole 12, and the fitting step portion 26a is fitted in the housing 11 while closing the ceiling (opening) of the housing 11 with the flange 26 to rotate the damper. (D) can be assembled.

In addition, although description of operation | movement is abbreviate | omitted, since the some rib 31B is equally pressed against the inner periphery of the housing 11, torque becomes constant.

The rotary damper D according to the third embodiment cannot fluctuate (change) torque, but the same effects as in the first embodiment can be obtained.

In the use of the rib 31B as the friction body, since the rib 31B is integrally molded with the rotor 21, the rotary damper D can be manufactured at low cost.

8 is an exploded perspective view in which part of the assist grip device according to the present invention is omitted. In addition, the same code | symbol is attached | subjected about the part same as FIG. 1 thru | or 7, and the description is abbreviate | omitted.

In FIG. 8, reference numeral A denotes an assist grip device, brackets 61A and 61B for attaching the assist grip 81 to a predetermined position, and a rotary damper D for braking the rotation of the assist grip 81. ), A torsion spring 71 as a gripping means for holding the assist grip 81 to the return position, and an approximately 'c' shaped assist grip 81 rotatably attached to the brackets 61A and 62B. And a support shaft 91 for attaching the rotary damper D, the torsion spring 71 and the assist grip 81 to the brackets 61A and 61B.

The brackets 61A and 61B are provided with an attachment portion 62 having an attachment hole 62a and an axial support hole 63a for supporting the support shaft 91 and protrude downward from the attachment portion 62. It consists of a pair of support piece 63 formed so that it may become.

The interval between the pair of support pieces 63 and 63 is approximately equal to the height (H shown in FIG. 1) of the rotary damper D, and inside the support piece 63 of one side of the bracket 61A. A groove 63b into which the engaging projection 25 of the rotary damper D is fitted is formed on a straight line passing through the shaft support hole 63a.

A through hole 82 through which the support shaft 91 penetrates is formed at an end portion of the assist grip 81 that covers the brackets 61A and 61B.

At the end of the assist grip 81 covering the bracket 61A, a fitting hole (or fitting recessed portion) 83 into which the protrusion 13a of the rotary damper D is fitted is formed.

Next, an example in which the assist grip 81 is attached will be described.

First, each of the brackets 61A, 61B is attached to a predetermined position of the skin attachment part, not shown, using an attachment screw and an attachment hole 62a, not shown.

The rotary damper D is positioned between the pair of support pieces 63 and 63 of the bracket 61A while fitting the engaging projection 25 into the groove 63b. At this time, when attaching the assist grip 81 thereafter, the housing 11 is rotated and positioned in advance so that the projection 13a can be fitted into the fitting hole 83.

Then, each bracket 61A, 61B is covered with the end of the assist grip 81 while fitting the projection 13a into the fitting hole 83, and the through hole 82, the shaft support hole 63a, and the shaft support hole One end side of the assist grip 81 is rotatably attached to the bracket 61A by sandwiching the support shaft 91 through the 12a, the through hole 22a, the shaft support hole 63a, and the through hole 82. The other end side of the assist grip 81 is inserted by inserting the support shaft 91 into the through hole 82, the shaft support hole 63a, the torsion spring 71, the shaft support hole 63a, and the through hole 82. It can be attached to the bracket 61B so that rotation is possible. Further, the torsion spring 71 is provided in a state in which the assist grip 81 is supported so as to return the assist grip 81 to a return position, for example, to an upper predetermined position.

Subsequently, the operation will be described.

In order to use the assist grip 81 attached as described above, when the assist grip 81 is pulled and rotated downward while resisting the holding force of the torsion spring 71, the fitting grip 83 is fitted in the fitting hole 83. The housing 11 is rotated through the protrusion 13a, but since the rotation of the rotor 21 is restricted by the engaging protrusion 25 fitted in the groove 63b, the rotation of the assist grip 81 is prevented. Braking.

Then, when the hand is released to return the assist grip 81 to the return position after use, the assist grip 81 is returned to the return position by the holding force of the torsion spring 71.

In this way, even when the assist grip 81 returns to the return position by the holding force of the torsion spring 71, the rotation of the assist grip 81 is braked.

According to the assist grip apparatus A of this invention, since the rotary damper D was provided on the support shaft 91, the part which supports the assist grip 81 axially can be made compact.

Further, the rotary damper D has a torque changing means, and the assist grip 81 can be smoothly returned to the return position by setting the position where the torque decreases to the return position of the assist grip 81.

In the above-described embodiment, although the shaft support hole 12a is formed in the bottom portion 12 of the housing 11 and the through hole 22a is formed in the rotor 21, the shaft support hole 12a and the through hole ( Needless to say, it is not necessary to form 22a).

Moreover, although the through-hole 22a was formed in the rotor 21 and the engaging protrusion 25 was formed, the hanger which integrally rotates and rotates these to the rotor 21 and the support shaft 91 is carried out. The same effect can be obtained also by forming a fitting means, eliminating the engaging projection 25 and making the rotor 21 protrude from the flange 26 (housing 11).

Moreover, although the projection 13a was formed in the circumferential wall 13 of the housing 11, and this projection 13a was made to engage with the fitting hole 83 of the assist grip 81, this projection Instead of the 13a and the fitting hole 83, the outer shape of the circumferential wall 13 may be a shape other than a circular shape, and may serve as a locking means for integrally rotating with the assist grip 81.

Moreover, although the O-ring 31 and the rubber bush 31A were shown as a friction body provided in the outer periphery of the shaft part 22, it can be manufactured inexpensively by making a friction body into the felt bush. In order to obtain lubricity, grease and silicone oil may be applied or may have self-lubricating property.

In addition, although the flange 26 integrally formed in the shaft portion 22 was used as a cap, the cap was formed in a separate structure, and the cap was formed by forming a shaft support hole through which the shaft portion 22 protrudes. Even if it is detachably caught, the number of parts increases, but the same effect can be obtained.

Moreover, the shaft support hole 12a is formed in the housing 11, the through hole 22a is formed in the rotor 21, and the support shaft 91 is made into the shaft support hole 12a and the through hole 22a. The rotary damper (D) is installed on the support shaft (91), but the rotary damper (D) is installed on the extension line of the support shaft (91) to be used as the support shaft, or the rotary damper (D) is supported. The assist grip 81 is also provided at a position away from the shaft 91 and transfers the support shaft 91 that rotates together with the assist grip 81 to the rotor 21 by a transmission mechanism via a gear. ) Can be braked.

As described above, according to the rotary damper of the present invention, the rotary damper can be assembled by inserting the friction body in the outer circumference of the rotor and pressing the friction body into the inner circumference of the housing while inserting the rotor into the housing. The assembling operation is simple and easy, and the rotary damper can be assembled efficiently.

In addition, since there is no use of a fluid such as a viscous fluid and there is no sealing part by welding, it is possible to easily and easily change the torque by disassembling and changing the friction body or adjusting the length of the friction body after assembly. .

In addition, since the torque changing means for varying the torque is formed, the assist grip is close to the return position, for example, when braking the assist grip axially rotatably supported and supported by the holding means to the return position. Since the holding force of the holding means decreases, the assist grip can be smoothly returned to the return position by reducing the torque when the assist grip approaches the return position.

In addition, since the cap is formed integrally with the rotor, the number of parts can be reduced and the production can be made at a low price.

Since the friction body is an O-ring, the torque can be easily and easily changed by changing the number of O-rings, and the rotary damper can be manufactured at low cost.

In addition, since the friction body is integrally molded to the rotor with a soft synthetic resin, the number of parts can be reduced and the production can be made at a low price.

According to the assist grip device of the present invention, since the rotation of the assist grip is braked by the rotary damper of the present invention, a certain braking effect can be obtained.

The assist damper can be smoothly returned to the return position by the rotation damper having the torque changing means and the position where the torque decreases as the return position of the assist grip.

In addition, since the rotary damper is provided on the support shaft, the portion supporting the assist grip axially can be made compact.

Claims (8)

A cylindrical housing having a bottom and an open ceiling; A rotor inserted into the housing, It is installed on the outer circumference of the rotor and pressed against the inner circumference of the housing, and made of a friction body having elasticity to generate a frictional resistance between the inner circumference of the housing or between the outer circumference of the rotor Rotating damper characterized in that. A cylindrical housing in which a hole is formed in the center of the bottom and the ceiling is opened; A rotor inserted into the housing and having a through hole communicating with the hole; It is installed on the outer circumference of the rotor and pressed against the inner circumference of the housing, and made of a friction body having elasticity to generate a frictional resistance between the inner circumference of the housing or between the outer circumference of the rotor Rotating damper characterized in that. A cylindrical housing having a concentric shaft support portion and a hole formed in the bottom portion and a ceiling opening; A rotor inserted into the housing and rotatably supported at one end of the shaft support portion, the rotor having a through hole communicating with the hole; A cap that closes the ceiling of the housing and rotatably supports the other end of the rotor so that the rotor rotates on the axis of the shaft support; It is installed on the outer circumference of the rotor and press-contacted to the inner circumference of the housing, made of a friction body having elasticity to generate a frictional resistance between the inner circumference of the housing or between the outer circumference of the rotor and , And a torque shifting means in the housing and the rotor for varying the torque by varying the thickness in the radial direction of the friction body in a predetermined range in which the housing and the rotor rotate relatively. The method according to claim 3, And the cap is integrally formed with the rotor to rotate about the housing. The method according to any one of claims 1 to 4, The friction body is a rotary damper, characterized in that composed of one or more O-rings. The method according to claim 1 or 2, And the friction body is formed of a soft synthetic resin integrally with the rotor. An assist grip device for holding a pivotally supported assist grip in a return position by a holding means, the assist grip device comprising: An assist grip device, wherein the rotation of the assist grip is braked by the rotary damper according to any one of claims 1 to 6. The method according to claim 7, And the rotary damper is provided on a support shaft for supporting the assist grip in a rotatable manner.