GB2385653A

GB2385653A - A rotary damper and assist grip device incorporating such a rotary damper

Info

Publication number: GB2385653A
Application number: GB0302920A
Authority: GB
Inventors: Masaharu Shibao
Original assignee: Nifco Inc
Current assignee: Nifco Inc
Priority date: 2002-02-14
Filing date: 2003-02-10
Publication date: 2003-08-27
Anticipated expiration: 2023-02-10
Also published as: JP4166986B2; GB2385653B; DE10306014A1; KR100525560B1; GB0302920D0; KR20030068380A; JP2003237447A; TW572150U

Abstract

A rotary damper 10 comprises a cam device 11, an elastic biassing member 12 for urging the cam device 11 in a predetermined direction, and a storage case 13 for storing the cam device 11 and biassing member 12. The cam device 11 is supported by the storage case 13 to be movable only along the axial direction of the storage case 13. The rotary damper 10 can be incorporated in an assist grip (see Fig. 4) for the interior of a motor vehicle, the rotary damper providing a damping force which returns the assist grip from an operational position to an original rest position.

Description

Title of the Invention

ROTARY DAMPER AND ASSIST GRIP DEVICE

Background of the Invention and Related Art Statement

5 [0001] The present invention relates to a rotary damper for applying a damping force onto a rotating device with an elastic member, and also relates to an assist grip device with the rotational damper.

10002] Fig. 13 is a view showing an example of a 10 conventional rotary or rotational damper. A rotational damper is formed of a pair of the first cams 2 with engagement surfaces facing each other, which is fixed to an axis 1 with an interval, and a pair of the second cams 3 disposed inside the first cams 2 to engage the first cam at an inclined surface 3a with each other, and urged outwardly by an elastic member 4.

3] In the rotational damper with the above-

mentioned structure, the second cams 3 are unable to rotate because of a fixing device (not shown), and also 20 are supported to be able to slide in an axial direction.

When the axis 1 is rotated in the arrow A direction, each of the second cams 3 moves closer to each other against a spring force of the elastic member 4 due to the inclined surface. Because of the spring force, the rotation of 25 the axis 1 is limited.

4] However, the conventional damper with the above-mentioned structure has many parts and each

component is not integrated, thereby resulting in poor workability in assembly and a large space. Also, when the conventional damper is assembled, there is a problem in assembly due to shifting in a rotational direction and 5 an inferior torque transfer.

5] The present invention has been made in order to solve the abovementioned problems, and an object of the present invention is to provide a rotational damper, which is compact for easy storage in a case and has 10 excellent workability in assembly.

6] Further objects and advantages of the invention will be apparent from the following description of the

invention. 15 Summary of the Invention

7] In order to achieve the above-mentioned objectives, according to the first aspect of the invention, a rotary or rotational damper includes a cam device, an elastic member for urging the cam device in a 20 predetermined direction, and a storage case with a bottom for storing the cam device and the elastic member. The cam device is supported to be movable only in an axial direction of the storage case.

8] Also, according to the second aspect of the 25 invention, the cam device has a cam surface formed on a side end surface thereof, and is urged in a direction that the cam surface projects by the elastic member.

[00091 Also, in the third aspect of the invention, the cam device is stored in the storage case, and is unable to ro late. Further, in the Courtly aspect of the invention, the cam device and the storage case include a 5 hole for inserting an axis, or a shaft.

0] According to the fifth aspect of the invention, a rotational damper is provided with cam devices, an elastic member for urging the cam devices in the predetermined directions, and a storage case having two 10 openings at both ends for storing the cam devices and the elastic member. The cam devices are supported to be movable only in the axial directions at the both ends of the storage case.

1] In the sixth aspect of the invention, an assist 15 grip device urges an assist grip supported with an axis to be rotatable to a retracted position. The assist grip is provided with a rotational damper having a cam device, an elastic member for urging the cam device in a predetermined direction, and a storage case for storing 20 the cam device and elastic member at a supporting depressed portion of the assist grip. The cam device is supported to be movable only in the axial directions of the storage case, and includes the rotational damper for urging the assist grip in a return direction.

Brief Description of the Drawings

2] Fig. 1 is a longitudinal sectional view showing a rotational damper according to the present invention; Fig. 2 is an exploded perspective view of the rotational damper; 5 Figs. 3(a) and 3(b) are longitudinal sectional views showing other embodiments of the rotational damper; Fig. 4 is an exploded perspective view showing an assist grip device with the rotational damper of the invention; 10 Fig. 5 is an enlarged perspective view showing an essential portion of a base portion of the assist grip; Fig. 6 is a view showing a state where the rotational damper is installed in the assist grip; Fig. 7 is a view showing a relation between the 15 assist grip and the rotational damper; Fig. 8 is a view showing a state of the rotational damper when the assist grip is not used Fig. 9 is a view showing a state of the rotational damper when the assist grip is used; 20 Fig. 10 is a developed view showing a cam device; Fig. 11 is a view seen from a direction 11 in Fig. 8 showing a state of the rotational damper when the assist grip is not usedi Fig. 12 is a view seen from a direction 12 in Fig. 9 25 showing a state of the rotational damper when the assist grip is used; and

Fig. 13 is a view showing an example of a conventional rotational damper.

Detailed Description of Preferred Embodiments

5 [0013] Hereunder, embodiments of the present invention will be explained in detail with reference to the accompanying drawings. Fig. 1 is a longitudinal sectional view showing a rotary or rotational damper according to the present invention, and Fig. 2 is an 10 exploded perspective view of the rotational damper of the present invention.

4] A rotary or rotational damper 10 is provided with a cam device 11, an elastic member (coil spring) 12 for urging the cam device 11 in a predetermined 15 direction, and a storage case 13 with a bottom for storing the cam device 11 and the elastic member 12. The cam device 11 is supported to be movable only in an axial direction of the storage case 13.

5] In Fig. 1, the cam device 11 is substantially 20 formed in a cylindrical shape and has a helical cam surface lla on an upper surface. The cam surface lla has the lowest point A and the highest point B (as shown in Fig. 10). An insertion hole llb is disposed at the center of the cam surface lla for inserting a shaft or an 25 axis. Engagement pieces tic are disposed at a sidewall of the cam device 11. The engagement piece tic is formed in a shape with cuts at three sides and includes an

engagement protrusion lid projecting toward an outer circumference. In the present embodiment, the engagement pieces Tic are disposed at positions facing each other.

Also, the sidewall has a notch portion lie.

5 [0016] According to the present embodiment, the elastic member 12 is formed of a compression coil spring and has a winding diameter larger than the insertion hole llb of the cam device 11. The storage case 13 has a cylinder shape with a bottom, and a protrusion 14 is 10 formed on the sidewall for preventing rotation. The protrusion 14 extends in the longitudinal direction of the storage case 13. An inner diameter of the storage case 13 is set to have a dimension so that the cam device 11 can be inserted therein. Further, the storage case 13 15 includes notch portions 15 that can engage the engagement pieces tic formed on the sidewall of the cam device 11.

Additionally, the storage case 13 includes a small cylinder portion 16 at the center thereof extending from a bottom wall 13a. An outer diameter of the small 20 cylinder portion 16 is formed to be smaller than the insertion hole llb of the cam device 11, and can be inserted into the insertion hole lib.

7] Next, an assembly of each component described above will be explained. First, the coil spring 12 is 25 inserted from an opening at an upper surface of the small cylinder portion 16 of the storage case 13. Next, the cam device 11 is inserted so that positions of the

engagement pieces Tic formed on the sidewall correspond to the positions of the notch portion 15. When the engagement protrusions lid formed on the engagement pieces tic are inserted, the engagement protrusions lid 5 are retracted as abutting against the inner surface of the storage case 13. Then, the engagement protrusions lid are returned by elastic forces once the engagement protrusions lid reach the notch portion 15, and are projected toward an outer circumference through the notch 10 portions 15. Because of these protrusions, the cam device 11 is prevented from pulling out from the storage - case 13. Also, when the cam device 11 is inserted, the coil spring 12 is compressed to urge the cam device upward. Additionally, because a longitudinal length of 15 the cam device 11 is shorter than that of the storage case 13, the cam device 11 can be inserted further.

8] Next, a motion of the rotational damper 10 according to the present invention will be explained.

First, a supporting shaft (not shown) is inserted into 20 the small cylinder portion 16 of the rotational damper 10, which does not rotate due to the protrusion 14. When a rotational member rotatably disposed on the supporting shaft rotates while contacting the cam surface lla, the cam device 11 is pushed down against the spring force of 25 the elastic member 12 as the rotational member moves from the point A toward the point B on the cam surface. In other words, the rotational member receives a stronger

pressing force as rotating further while contacting the cam surface lla, thereby receiving a damping force from the elastic member. Also, because the rotational damper is integrated in a compact size, it is easy to install.

5 [0019] Fig. 3(a) is a longitudinal sectional view showing another embodiment of the rotational damper of the present invention. In this embodiment, a rotational damper 20 is provided with cam devices 21, an elastic member 22 for urging the cam devices 21 in predetermined 10 directions, and a storage case 23 with open ends for storing the cam devices 21 and the elastic member 22.

The cam devices 21 are supported at the both ends of the storage case 23 to be movable only along the axial - direction.

15 [0020] The cam device 21 is formed in substantially a cylindrical shape and has a helical cam surface 21a on an upper surface. The cam surface 21a has the lowest point A and the highest point B as in the first embodiment.

Also, an insertion hole 21b is formed at the center of 20 the cam surface 21a for inserting a shaft. Additionally, engagement pieces 21c are formed on a sidewall of the cam device 21. The engagement piece 21c is formed in a shape with cuts at three sides and includes an engagement protrusion 21d projecting toward an outer circumference.

25 In the present embodiment, the engagement pieces 21c are disposed at positions facing each other.

1] In the present embodiment, the elastic member 22 is formed of a compression coil spring and has a winding diameter greater than the diameter of the insertion hole 21b of the cam device 21. The storage 5 case 23 has a cylinder shape with both open ends, and a protrusion (not shown) is formed on the sidewall for preventing rotation. An inside diameter of the storage case 23 is set to have a dimension so that the cam device 21 can be inserted therein. The storage case 23 includes 10 notch portions 25 that can engage the engagement pieces 21c formed on the sidewall of the above-mentioned cam devices 21. Additionally, the storage case 23 includes a small cylinder portion 26 at the center thereof, and the small cylinder 26 is supported and fixed by a support arm 15 23a. An outer diameter of the small cylinder portion 26 is formed to be smaller than the insertion hole 21b of the cam device 21, and can be inserted into the insertion hole 2lb.

2] Next, an assembly of each component described 20 above will be explained. First, one cam device 21 is inserted from one of the open ends of the storage case 23, and the engagement protrusions 21d are engaged with the notch portions 25 of the storage case 23. Next, the small cylinder portion 26 and the elastic member 22 are 25 stored inside of the storage case 23 from the other open end. In addition, the other cam device 21 is inserted.

When the engagement protrusions 21d are inserted, the

engagement protrusions 21d are retracted as abutting against the inner surface of the storage case 23. Then, the engagement protrusions 21d are returned by elastic forces once the engagement protrusions 21d reach the 5 notch portions 25, and project toward an outer circumference through the notch portions 25. Because of these protrusions, the cam devices 21 are prevented from pulling out from the storage case 23. Also, when the cam devices 21 are inserted, the coil spring 12 is compressed 10 to urge outward. Additionally, because a total longitudinal length of the two cam devices 21 is shorter than that of the storage case 23, the cam devices 21 can be inserted further.

3] With the above-mentioned structure, because the 15 cam devices 21 are disposed on both ends of the storage case 23, the cam devices 21 can be attached to a wider variety of devices to be damped. Additionally, in the installing process, it is not likely to assemble in a wrong way.

20 [0024] Fig. 3(b) is a longitudinal sectional view showing another embodiment of the present invention.

This embodiment is similar to the embodiment shown in Fig. 3(a). Instead of having the small cylinder portion, guiding portions 21f are provided for guiding edges of 25 the spring to the inner sides of the cam devices 21.

5] With the structure mentioned above, the small cylinder portion for guiding the spring case is not necessary, thereby reducing the numbers of the parts.

6] Fig. 4 is an exploded perspective view showing 5 an assist grip device with the rotational damper of this invention. Fig. 5 is an enlarged perspective view showing an essential portion of a base portion of the assist grip. Fig. 6 is a view showing a state where the rotational damper is installed in the assist grip. Fig. 10 7 is a view showing a relation between the assist grip and the rotational damper.

7] Here, the assist grip device 27 urges the assist grip 27a supported by a shaft to be rotatable toward a return position. The assist grip 27 is provided 15 at a supporting depressed portion 28 with the cam device 11, the elastic member 12 for urging the cam device 11 in a predetermined direction and the storage case 13 for storing the cam device 11 and the elastic member 12. The cam device 11 is supported to be movable only in the 20 axial direction in the storage case 13, and includes the rotational damper for urging the pulled out assist grip 27a toward the return position.

8] The assist grip 27a includes a fixed groove 29 in the supporting depressed portion 28. The protrusion 25 14 formed on the outer circumference surface of the rotational damper 10 engages the fixed groove 29, so that assist grip 27a rotates together with the storage case

13. Also, as shown in Fig. 5 and Fig. 6, a base 30 to be fixed to a car body is provided with a shaft hole 30a for inserting a support shaft supporting the rotational damper 10 and a protrusion 30b disposed around the shaft 5 hole 30a.

9] As shown in Figs. 4 and 6, the rotational damper 10 is installed between the arms 30d of the base 30, so that the cam surface lla contacts the protrusion 30b of the base 30. The base 30 is fixed to the car body 10 through a base edge portion 30c. Fig. 8 is a view showing a state of the rotational damper when the assist grip is not in use. Fig. 9 is a view showing a state of the rotational damper when the assist grip is in use.

Fig. 10 is an explanatory developed view showing a cam 15 device. Fig. 11 is a view seen from the direction 11 showing a state of the rotational damper when the assist grip is not in use. Fig. 12 is a view seen from the direction 12 showing a state of the rotational damper when the assist grip is in use 20 [0030] In the state shown in Fig. 8, the assist grip 27a is not used, and the protrusion 30b formed in the arm 30d of the base portion 30 is located in the lowest position A of the cam surface lla. This corresponds to the condition shown in Fig. 11. In this state, the 25 assist grip 27a does not receive the urging force from the cam surface lla,

1] Next, when the assist grip 27a is pulled out, the rotational damper 10 is rotated with the assist grip.

The protrusion 30b of the base abuts against a higher position of the cam surface and gradually receives a 5 stronger urging force. Fig. 9 shows the state that the protrusion 30b of the base contacts the highest position of the cam surface. The assist grip 27a is in the completely opened state, and Fig. 12 corresponds to this state. The assist grip 27a opens approximately 120130 10 degrees. When the hand is released from the assist grip in this state, the assist grip returns to the original position by the urging force of the rotational damper 10.

[00321 The assist grip with the above-mentioned structure can apply the damping force through the spring 15 in an automobile. Therefore, it is possible to reduce a manufacturing cost through the reduction of the number of the parts and improve workability.

[00331 In the above embodiments, the rotational damper is used for the assist grip device installed inside the 20 automobile. However, the invention is not limited to the embodiments, the rotational damper can be used for other devices that perform opening and closing movements.

tO034] With the structures mentioned above, the present invention can obtain the following effects. In 25 the first aspect of the invention, the rotational damper includes the cam device, the elastic member for urging the cam device in the predetermined direction, and the

storage case with a bottom for storing the cam device and the elastic member. The cam device is supported to be movable only in the axial direction of the storage case.

With this structure, the rotating device presses the cam 5 surface when rotating, thereby receiving the damping force by the spring force from the elastic member [0035] In the second aspect of the invention, the cam surface is provided on the side edge surface of the cam device, and the elastic member urges the cam surface in 10 the direction that the cam surface projects. Therefore, the rotational motion of the rotation device is converted to the straight motion to contract the elastic member.

6] Also, in the third aspect of the invention, because the cam device is stored not to rotate in the 15 storage case, the rotary motion of the rotational device is converted to the straight motion to contract the elastic member. Further, in the fourth aspect of the invention, because the cam device and the storage case include the hole for inserting the shaft, the supporting 20 shaft is inserted into the hole to utilize the cam device and the storage case.

7] Further, in the fifth aspect of the invention, the rotational damper is provided with the cam devices, the elastic member for urging the cam devices in the 25 predetermined directions, and the storage case with openings at both ends for storing the cam devices and elastic member. The cam devices are supported at the

l both ends of the storage case to be movable only in the axial directions, so that the cam devices create greater damping force with the rotation of the rotation device.

8] Further, in the sixth aspect of the invention, 5 the assist grip device urges the assist grip supported by the shaft to be rotatable toward the return position.

The cam device, the elastic member for urging the cam device in the predetermined direction, and the storage case for storing the cam device and elastic member are 10 disposed in the support depressed portion of the assist grip. The cam device is supported to be movable only in the axial directions of the storage case, and contains the rotational damper for urging the assist grip to the return direction. Thus, the numbers of the parts can be 15 reduced and the assembly steps can be largely reduced.

Also, because of the compact structure of the whole device, when the rotational damper is assembled, it is possible to eliminate problems in assembly due to shifting in the rotational direction and an inferior 20 torque transfer.

Claims

What is claimed is:

1. A rotary damper, comprising: a case having a cylindrical main body, at least one cam device disposed in the case, and 5 an elastic member disposed in the main body for urging the cam device in a predetermined direction, wherein said at least one cam device is supported to be movable only along an axis of the cylindrical main body.

10 2. A rotary damper according to claim 1, wherein said cam device includes a cam surface formed on a side surface thereof, and the elastic member urges the cam device in a direction that the cam surface projects.

15 3. A rotary damper according to claim 1 or 2, further comprising an engagement portion for engaging between the case and the cam device so that the cam device does not rotate relative to the case. 20 4. A rotary damper according to any one of claims 1 to 3, further comprising a hole disposed in the cam device and the case for inserting a shaft along the axis.

5. A rotary damper according to any one of claims 1 to 4, wherein 25 said at least one cam device includes an engagement piece at a side opposite to a cam surface and an engagement protrusion at one side of the engagement piece, and said cylindrical main body

further includes a groove at a side portion of the cylindrical main body for receiving the engagement protrusion so that the at least one cam device can move along the axis of the case without rotation and disengagement with respect to the case.

6. A rotary damper according to claim 2, wherein said cam surface is formed in a circular shape with a hole at a center thereof, and has a slope inclined in a spiral form along a circumference thereof. 7. A rotary damper according to any one of claims 1 to 6, further comprising a cylindrical portion disposed in the case for inserting a shaft along the axis, said cylindrical portion communicating from one end of the case to the other end thereof, said elastic member being arranged around the cylindrical portion.

8. A rotary damper according to any one of claims 1 to 7, wherein said case has openings at both ends, and two cam devices are disposed at the both ends to move along the axis.

9. An assist grip device comprising said rotary damper according to any of claims 1 to 8, and an assist grip having the rotational damper arranged in a supporting depressed portion thereof so that the assist grip after being rotated can be retu med to an original 25 position with a damping force of the rotary damper.

10. A rotary damper according to any one of claims 1-8, as shown and described in the specification and drawings.

11. An assist grip device according to claim 9, as shown and 5 described in the specification and drawings.

12. A rotary damper according to any one of preceding claims 1, 3 to 5, 7 or 8 wherein said cam device has a cam suface formed on a radially directed face thereof.

13. A rotary damper according to claim 12 wherein said cam surface is formed in an annular shape and has a slope inclined in a spiral form along said radially directed face.

15 14. A rotary damper substantially as hereinbefore described with reference to the accompanying description and Figures 1 and 2; or

Figures 3(a) and 3(b) of the drawings.

15. An assist grip device substantially as herebefore described 20 with reference to the accompanying description and Figures 4 to 12

of the drawings.