The present invention relates to a damping structure for a rotating member, and especially, it relates to a damping structure for a rotating member used in an assist grip of an automobile.
As a movable or swingable type assist grip installed in an automobile, there has been known an assist grip provided with urging means, such as a spring, for returning the assist grip from a use position to a stored position, and a damper for damping or applying a brake on the assist grip which swings in a returning direction by an urging force of the urging means. As an example, there can be exemplified an assist grip disclosed in Japanese Patent Publication (KOKAI) No. H9-263166. FIG. 9 shows a support section at a side to which a damper of an assist grip disclosed in Japanese Patent Publication (KOKAI) No. H9-263166 is attached, which will be explained hereunder.
As shown in the figure, in one of support sections of an assist grip 100, a grip member 104 is attached to a base member 102 fixed on a wall, such as a ceiling section of an interior of an automobile, through a damper 106.
The damper 106 is formed of an outer cylinder 108 made of resin and an inner shaft 110 made of metal. In the outer cylinder 108, a small diameter portion 112 at a distal end side of an inserting direction is inserted into a small diameter coaxial hole 114 of the base member 102, and a knurl portion 118 formed on an outer peripheral surface of a large diameter portion 116 at a base end side of the inserting direction is fixed, not to rotate, to a hole wall of a large diameter coaxial hole 120 of the base member 102.
In the inner shaft 110 rotatably inserted inside the outer cylinder 108, a small diameter portion 122 at the distal end side of the inserting direction is inserted and fitted into a small diameter coaxial hole 124 of the grip member 104, and a knurl portion 126 at the base end side of the inserting direction is fixed, not to rotate, to a hole of a large diameter coaxial hole 128 of the grip member 104.
Then, a space formed between a large diameter portion 130 of the inner shaft 110 and a housing hole 132 of the outer cylinder 108 is filled with damper oil, and seal rings 136 are respectively fitted into a pair of seal ring grooves 134 formed at both end portions in the axial direction of the large diameter portion 130 such that the space is sealed.
On the other hand, in the other supporting section of the assist grip 100, which is not shown in the figure, urging means is installed, and the urging means constantly urges the assist grip to a wall surface side (stored position).
Accordingly, in the assist grip 100 which is returned from the use position to the stored position by the urging force of the urging means, a returning speed thereof is suppressed due to viscous resistance by oil in the damper 106, so as to prevent the assist grip from colliding with the wall surface at high speed.
However, in the conventional assist grip as described above, the assembly of the damper is carried out together with the assembly of a rotating shaft. Namely, while the grip member 104 is positioned at the base member 102, the inner shaft 110 is inserted into the outer cylinder 108 from the axial direction to form the damper 106, and at the same time, the small diameter portion 122 at the distal end of the inner shaft 110 is positioned at the small diameter coaxial hole 124 of the grip member 104 to be inserted thereinto. Therefore, a working ability in assembly is poor.
Also, since the grip member 104 is axially supported at the base member 102 through the damper 106 having a damping function, a force or load applied to the grip member 104 naturally acts on the damper 106 as well. Thus, there are problems of giving harmful effects on damping and durability, such that the frictional resistance at the slide contact portions 138A, 138B and 138C, where the inner shaft 110 contacts the outer cylinder 108, is increased to change the damping force, or the entire damper 106 may be bent to cause oil leakage.
The present invention has been made in view of the foregoing, and an object of the invention is to provide a damping structure of a rotating member and an assist grip provided with the damping structure of the rotating member, in which a workability in assembly is improved and the rotating member is excellent in durability while damping of the rotating member is normally carried out.
Further objects and advantages of the invention will be apparent from the following description of the invention.
To achieve the above object, a damping structure of a rotating member according to a first aspect of the invention is formed of a base, which includes a plurality of projecting portions arranged at predetermined intervals and each having shafts projecting in the same direction and coaxially disposed or holes opening in the same direction and coaxially disposed; a rotating member, which has a plurality of wall portions corresponding to the projecting portions and each having inserting holes fitted around the shafts or inserting shafts inserted into the holes so that the rotating member is axially supported by the base to be freely rotatable, in which the rotating member in an axially supported condition and one of the projecting portions adjacent to one of the wall portions form a space therebetween; and a damper, which includes an inner shaft and an outer cylinder. The damper has side surfaces stored in the space, and the side surfaces of the damper respectively abut against the projecting portion and the wall portion. The inner shaft includes an engaging portion engaging an engaging portion provided in the projecting portion, and is disposed coaxially to the shafts or the holes. The outer cylinder is attached rotatably around the inner shaft and generates a damping force against a rotation relative to the inner shaft. The outer cylinder has an engaging portion engaging an engaging portion provided in the rotating member.
In the damping structure of the rotating member according to the first aspect of the invention, a rotation of the rotating member free rotatably supported by the base is damped due to a damping force of the damper disposed between the base and the rotating member. The base is provided with a plurality of the projecting portions disposed at predetermined intervals, and the projecting portions are respectively provided with the shafts having the same projecting direction and arranged coaxially, or the holes having the same opening direction and disposed coaxially. The rotating member is provided with the plurality of wall portions corresponding to the plurality of the projecting portions, and the wall portions are respectively provided with the inserting holes or the inserting shafts, so that when the inserting holes are fitted around the shafts or the inserting shafts are inserted into the holes of the base from the predetermined direction, the axially supported condition described above is obtained.
Here, when the inserting holes are fitted around the shafts or the inserting shafts are inserted into the holes, a space is formed between the rotating member and the projecting portion adjacent to one of the plurality of wall portions. When the damper is stored in the space, the opposing side surfaces of the damper abut against the projecting portion and the wall portion, so that the rotating member is prevented from falling off from the base.
The damper is formed of the inner shaft and the outer cylinder rotatably attached around the inner shaft, and in the condition that the damper is stored in the space, a shaft center of the inner shaft is aligned with a shaft center of the shaft or the hole (inserting hole or inserting shaft). Also, the engaging portion of the inner shaft is engaged with the engaging portion provided in the projecting portion of the base, so that the inner shaft is fixed not to rotate to the base side, and the fourth engaging portion of the outer cylinder is engaged with the engaging portion provided in the rotating member so that the outer cylinder is rotated together with the rotating member.
Accordingly, when the rotating member is rotated, in accordance with the rotation thereof, the outer cylinder of the damper is relatively rotated with respect to the inner shaft, and the resistance force is caused between the inner shaft and the outer cylinder to thereby apply the brake on the rotating member. As the resistance force, for example, a mechanical frictional resistance, or viscous resistance of the viscous fluid, such as oil, filling a space between the inner shaft and the outer cylinder, can be utilized.
As described above, in the damping structure of the rotating member of the invention, the inserting holes or the inserting shafts of the rotating member are inserted around the shafts or into the holes of the base from the predetermined direction so as to axially support the rotating member, and while the damper is stored in the space formed between the projecting portion of the base and the wall portion of the rotating member in the axially supported condition, by merely engaging the respective engaging portions with each other, the assembly is completed. Therefore, as compared with the conventional damping structure, there are no complicated steps of assembling the damper together with inserting the rotational shaft, so that the assembly is simplified. Further, since the damper can be assembled by itself, replacement of the damper can be made easily.
Also, in the use condition such that the load in the diametral direction is applied to the rotating member as in the assist grip, since the force applied to the rotating member is supported by the base through the axial support section (fitting portion between the shaft and the inserting hole or between the hole and the inserting shaft), the force does not directly act on the damper. Thus, the change in the damping force is prevented, and the durability of the damper is improved.
A damping structure of a rotating member according to a second aspect of the invention is formed of a base provided with a projecting portion, which has a shaft or a hole; a rotating member having a first wall portion, which includes an inserting hole inserted by the shaft or an inserting shaft inserted into the hole and is free rotatably supported at the projecting portion of the base, and a second wall portion opposed to the first wall portion and disposed at a forward side in a direction of inserting the inserting hole or inserting shaft, in which the second wall portion in an axially supported condition and the projecting portion form a space therebetween; and a damper having an inner shaft and an outer shaft. The damper is stored in the space, and side surfaces opposed to each other of the damper abut against the projecting portion and the second wall portion. The inner shaft is disposed coaxially to the shaft or the hole, and has an engaging portion engaging an engaging portion provided in the projecting portion. The outer cylinder is rotatably attached around the inner shaft and generates a damping force against a rotation relative to the inner shaft. The outer cylinder has an engaging portion engaging an engaging portion provided in the rotating member.
In the damping structure according to the second aspect of the invention, the base is provided with the projecting portion, and the shaft or the hole is provided in the projecting portion. The rotating member is provided with the first wall portion corresponding to the projecting portion, and the inserting hole or the inserting shaft is formed in the first wall portion, so that when the inserting hole is fitted around the shaft at the base side or the inserting shaft is inserted into the hole at the base side, the axially supported condition described above is obtained. Further, in the rotating member, the second wall portion opposed to the first wall portion is disposed at a forward side of the inserting direction, and when the rotating member is axially supported by the base, the space is formed between the second wall portion and the projecting portion. When the damper is stored in the space, as in the damping structure according to the first aspect of the invention, the opposing side surfaces of the damper abut against the projecting portion and the wall portion, so that the rotating member is prevented from falling off from the base.
As in the first aspect of the invention, the structure of the damper is formed of the inner shaft and the outer cylinder rotatably attached around the inner shaft. In the condition that the damper is stored in the space, a shaft center of the inner shaft is aligned with a shaft center of the shaft or the hole (inserting hole or inserting shaft). Also, the engaging portion of the inner shaft is engaged with the engaging portion formed in the projecting portion of the base so that the inner shaft is stopped at the base side so as not to rotate, and the engaging portion of the outer cylinder is engaged with the engaging portion provided in the rotating member, so that the outer cylinder is rotated together with the rotating member.
Thus, the outer cylinder of the damper is rotated due to the rotation of the rotating member, and the resistance force is caused between the outer cylinder and the inner shaft, to thereby apply the brake on the rotating member. Also here, as the resistant force, the mechanical frictional resistance or the viscous resistance of the viscous fluid can be utilized.
Therefore, also in this damping structure of the rotating member, the inserting hole or the inserting shaft of the rotating member is fitted around the shaft or inserted into the hole of the base from the predetermined direction to axially support the rotating member, and while the damper is stored in the space between the projecting portion of the base and the second wall portion of the rotating member, by merely engaging the respective engaging portions with each other, the assembly is completed. Therefore, the assembly can be made easily.
Also, even in the embodiment that the load in the diametral direction is applied to the rotating member, as in the damping structure of the first aspect of the invention, the force applied to the rotating member is supported by the axial support section between the rotating member and the base so that the force does not act on the damper. Therefore, a change in the damping force or the deterioration in the durability can be prevented.
According to a third aspect of the invention, the damping structure of the rotating member according to the first aspect or the second aspect of the invention further includes holding means for holding the damper stored in the space.
In the damping structure according to the third aspect of the invention, since the damper is held by the holding means, the damper is prevented from disengaging from the storage space (base and the rotating member), so that falling off due to the vibration or impact can be prevented.
According to a fourth aspect of the invention, in the damping structure of the rotating member according to the third aspect of the invention, the holding means is formed of an elastic member, which is integrally formed with the base to be elastically deformable, and the elastic member supports the outer cylinder of the damper.
In the damping structure according to the fourth aspect of the invention, by forming the holding means by the elastically deformable elastic member formed integrally with the base, the structure thereof can be simplified, and manufactured at low cost. Also, since the damping structure of the invention does not have a tightening structure, such as screw, or a mechanical fixing structure, the assembly of the damper can be easily carried out.
According to a fifth aspect of the invention, the damping structure according to any of the first through fourth aspects of the invention can be applied to an assist grip.