JP2002039252A - Rebound stopper structure of damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of an oil lock state occasioned by deformation of a rebound stopper and to improve durability of a rebound stopper, in the rebound stopper structure of a damper. SOLUTION: In the rebound stopper structure of a damper 10, an annular gap 23 is provided between the inner periphery of the rebound stopper 20 and the outer periphery of a piston rod 12, and notches 24 and 25 are formed in the upper and lower end faces of the rebound stopper 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damper rebound stopper structure.

[0002]

2. Description of the Related Art A damper such as a hydraulic shock absorber for a vehicle has a piston rod inserted into a cylinder, and is provided with a rebound stopper made of rubber or the like on the outer periphery of the piston rod inside the cylinder. A rebound stopper is sandwiched between a rebound seat provided on a piston rod and a rod guide provided on a cylinder to elastically compress and deform in the axial direction, thereby absorbing impact energy and reducing impact noise when the cylinder is fully extended.

In such a damper, a rebound stopper which also deforms in the radial direction at the time of extension and abutment comes into contact with the inner periphery of the cylinder, thereby forming a closed chamber defined by the inner periphery of the cylinder and the rod guide above the rebound stopper. When the hydraulic oil is confined, it becomes an oil lock state, hinders bending of the rebound stopper against an impact load, and impairs the shock absorbing performance at the time of extension.

In the prior art described in Japanese Patent Application Laid-Open No. 2000-120757, a notch groove extending in the axial direction is provided in a part of the outer circumference of the rebound stopper over the entire length thereof, and the notch groove is provided. By functioning as an escape path for hydraulic oil, a closed chamber which causes an oil lock state is prevented from being formed above the rebound stopper.

[0005]

However, in the prior art, in order to avoid the occurrence of an oil lock state due to the deformation of the rebound stopper, a notch groove is provided on the entire length of the outer periphery of the rebound stopper. In the entire length, a thin portion is formed only in a part in the circumferential direction, and the thickness of the meat becomes uneven in the circumferential direction, resulting in poor durability.

SUMMARY OF THE INVENTION An object of the present invention is to prevent the occurrence of an oil lock state due to deformation of a rebound stopper and to improve the durability of the rebound stopper in a rebound stopper structure of a damper.

[0007]

According to a first aspect of the present invention, there is provided a piston rod inserted into a cylinder, and a rebound stopper is provided on the outer periphery of the piston rod inside the cylinder. In a rebound stopper structure of a damper capable of pressing a rebound stopper between a provided rebound seat and a rod guide provided on a cylinder, an annular gap is provided between an inner periphery of the rebound stopper and an outer periphery of the piston rod, and Notches are provided in the upper and lower end surfaces of the stopper.

According to a second aspect of the present invention, in the first aspect of the present invention, projections are further provided at a plurality of circumferential positions on the inner periphery of the rebound stopper, and the rebound stopper contacts the piston rod to form an annular gap. It is made to form.

According to a third aspect of the present invention, in the first or second aspect, the cross-sectional area of the notch provided on the upper and lower end faces of the rebound stopper is determined by adjusting the cross-sectional area of the annular gap provided between the notch and the outer periphery of the piston rod. This is set so as to be larger than the cross-sectional area.

[0010]

According to the first aspect of the present invention, the following effects are obtained. When the rebound stopper elastically compresses and deforms in the axial direction to reduce shock energy absorption and shock noise when the damper is extended, the hydraulic oil on the upper part of the rebound stopper that deforms in the radial direction and contacts the inner circumference of the cylinder , Escapes from the notch on the upper end surface through the annular gap on the inner circumference, and further escapes from the notch on the lower end surface to the oil chamber of the cylinder, thereby avoiding the occurrence of an oil lock state. Thereby, the bending of the rebound stopper against the impact load is not suppressed, in other words, the spring constant of the rebound stopper can be reduced, and the shock absorbing performance at the time of extension can be improved.

An annular clearance is provided on the inner periphery of the rebound stopper as an escape path for hydraulic oil over the entire length of the rebound stopper, and the thickness of the meat is not made uneven in the circumferential direction, so that the durability can be improved. .

By providing notches at the upper and lower end faces of the rebound stopper, resistance to compressive deformation at the initial stage of extension can be reduced (softened).

When the same notch is provided in the upper and lower end faces of the rebound stopper, the direction of assembly to the piston rod can be eliminated, and the assemblability can be improved.

According to the second aspect of the invention, the following operations are provided. Protrusions are provided at a plurality of circumferential positions on the inner periphery of the rebound stopper, and the rebound stopper abuts the piston rod to form an annular gap, whereby the annular gap can be stably formed.

The rebound stopper reduces the contact area with the piston rod to only the projection portion as compared with the rebound stopper which comes into contact with the outer periphery of the piston rod on the entire inner periphery, so that light press-fitting into the piston rod becomes easier, A stable mounting state without freely moving up and down around the outer periphery of the piston rod can be easily formed.

According to the third aspect of the invention, the following effects are obtained. The cross-sectional area A2 of the notch provided on the upper and lower end surfaces of the rebound stopper was made larger than the cross-sectional area A1 of the annular gap provided between the notch and the outer periphery of the piston rod. Therefore, the notch serving as an escape path for the hydraulic oil from the upper portion of the rebound stopper does not become a throttle, and the spring constant of the rebound stopper can be determined only by the spring characteristics of the constituent material of the rebound stopper. Can stabilize the shock absorbing performance.

[0017]

FIG. 1 is a schematic sectional view showing a main part of a damper, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, FIG. 3 shows a rebound stopper, (A) is a sectional view, (B) is an end view, FIG. 4 is a schematic cross-sectional view showing a compression deformation state of the rebound stopper, and FIG. 5 is a cross-sectional view showing a modification of the rebound stopper.

As shown in FIGS. 1 and 2, the damper 10 is used as a vehicle hydraulic shock absorber and has a cylinder 11 connected to one of an axle side and a vehicle body side and a piston rod 12 connected to the other. . The piston rod 12 is inserted from the rod guide 13 provided in the cylinder 11 into the interior of the cylinder 11 and can slide in the axial direction. The interior of the cylinder 11 is vertically moved by a piston (not shown) fixed to the insertion end. 14 and 15 (not shown) are defined. Damper 10
The shock absorber that the vehicle receives from the road surface is absorbed by a damping mechanism configured by providing a piston on the extension side flow path and the pressure side flow path connecting the upper and lower oil chambers 14 and 15 and providing a damping valve in those flow paths. The expansion and contraction vibration of the suspension spring is controlled.

However, the damper 10 is provided on the outer periphery of the piston rod 12 inside the cylinder 11 so that the rebound stopper 2
0, and when the piston rod 12 is fully extended, a rebound seat 16 provided on the piston rod 12;
The rebound stopper 20 is sandwiched between the rod guide 13 provided in the cylinder 11 and elastically deformed in the axial direction to absorb the impact energy and reduce the impact sound at the time of extension (FIG. 4).

The rebound stopper 20 is a long cylindrical body made of urethane rubber or the like, and has a large-diameter portion 21 and a small-diameter portion 22 arranged on the outer surface of the cylinder so as to form a bellows shape. To improve the performance.

Further, as shown in FIG. 3, when the rebound stopper 20 is elastically compressed and deformed in the axial direction when the damper 10 is extended and stretched, as shown in FIG. In order to prevent the hydraulic oil above the rebound stopper 20 that abuts against the inner circumference of the cylinder 11 from being trapped in the upper space and thereby cause an oil lock state, the inner circumference and the outer circumference of the piston rod 12 are also deformed. An annular gap 23 is provided therebetween, and concave portions 24A and 25A are provided on the upper and lower end surfaces, and the concave portions are cutouts 24 and 25. Recesses 24A, 25A
May be a V-shaped cross section, a semicircular cross section, or the like, in addition to a square cross section. The number of the notches 24 and 25 is four in this embodiment, but may be one or more. In addition, notch 24
25 to 25, it is preferable that the interval between adjacent cutouts 24 (25) in the circumferential direction is symmetrically arranged (in this embodiment, 4 equally arranged in the circumferential direction), but may be arbitrary. The annular gap 23 and the notches 24 and 25 are connected to each other to provide a way for hydraulic oil to escape from the space above the rebound stopper 20.

At this time, the rebound stopper 20 is provided with projections 26 at a plurality of inner circumferential positions (four equally arranged positions in the present embodiment).
Is brought into contact with the piston rod 12 and the piston rod 12
To form an annular gap 23.

The rebound stopper 20 determines the total cross-sectional area (flow path area) A2 of each of the notches 24 and 25 provided on the upper and lower end faces by the cross-sectional area of the annular gap 23 between the notch 24 and the outer periphery of the piston rod 12 (FIG. (Flow path area) is set to be larger than A1.

According to this embodiment, the following operations are provided. When the damper 10 is fully extended, the rebound stopper 20
When the oil is elastically compressed and deformed in the axial direction to absorb the shock energy and reduce the impact sound, the hydraulic oil above the rebound stopper 20 which is also deformed in the radial direction and abuts against the inner periphery of the cylinder 11 is cut off at the upper end face. The oil chamber 1 of the cylinder 11 passes from the notch 24 through the inner circumferential annular gap 23, and further from the notch 25 on the lower end face.
4 to avoid the occurrence of the oil lock state. Thereby, the bending of the rebound stopper 20 with respect to the impact load is not suppressed, in other words, the spring constant of the rebound stopper 20 can be reduced, and the shock absorbing performance at the time of extension can be improved.

An annular clearance 23 is provided on the inner periphery of the rebound stopper 20 as an escape path for hydraulic oil over the entire length of the rebound stopper 20, and the thickness of the meat is not made uneven in the circumferential direction, so that durability is improved. Can be improved.

By providing the notches 24 and 25 at the upper and lower end faces of the rebound stopper 20, the resistance to the compressive deformation at the initial stage of the elongation can be reduced (softened).

When the same notches 24 and 25 are provided on the upper and lower end surfaces of the rebound stopper 20, the direction of assembly to the piston rod 12 can be eliminated, and the assembly can be improved.

Protrusions 26 are provided at a plurality of circumferential positions on the inner periphery of the rebound stopper 20, and the rebound stopper 20 abuts the projections 26 on the piston rod 12 to form the annular gap 23, thereby stabilizing the annular gap 23. Can be formed.

The rebound stopper 20 reduces the contact area with the piston rod 12 to only the projection 26 as compared with the one that abuts on the outer circumference of the piston rod 12 on the entire inner circumference to reduce the lightness of the piston rod 12. Press-fitting becomes easy, and a stable mounting state without freely moving up and down around the outer periphery of the piston rod 12 can be easily formed.

The cross-sectional area A2 of the notches 24 and 25 provided on the upper and lower end faces of the rebound stopper 20 is changed to the cross-sectional area A1 of the annular gap 23 provided between the notch 24 and the outer periphery of the piston rod 12.
Made larger. Therefore, the notches 24, 2 serving as escape paths for the hydraulic oil from the upper portion of the rebound stopper 20 as described above.
5 does not become a throttle, the spring constant of the rebound stopper 20 can be determined only by the spring characteristics of the constituent material of the rebound stopper 20, and the shock absorbing performance at the time of extension can be stabilized.

The difference between the rebound stopper 30 and the rebound stopper 20 shown in FIG.
A, 32A are provided, and a notch 31 is provided between adjacent convex portions 31A.
Is that a notch 32 is formed between the adjacent convex portions 32A, and these notches 31, 32 are connected to the annular gap 23 to form an escape path for hydraulic oil.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific structure of the present invention is not limited to this embodiment, and the design can be changed without departing from the scope of the present invention. The present invention is also included in the present invention.

[0033]

As described above, according to the present invention, in the rebound stopper structure of the damper, the occurrence of an oil lock state due to the deformation of the rebound stopper can be avoided, and the durability of the rebound stopper can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a main part of a damper.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG.

FIGS. 3A and 3B show a rebound stopper, wherein FIG. 3A is a sectional view and FIG. 3B is an end view.

FIG. 4 is a schematic sectional view showing a compression deformation state of a rebound stopper.

FIG. 5 is a cross-sectional view showing a modification of the rebound stopper.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Damper 11 Cylinder 12 Piston rod 13 Rod guide 16 Rebound seat 20, 30 Rebound stopper 23 Annular gap 24, 25, 31, 32 Notch

Claims (3)

[Claims] A piston rod inserted into a cylinder, a rebound stopper is provided on the outer periphery of the piston rod inside the cylinder, and a rebound seat provided on the piston rod when the piston rod is fully extended and a rod guide provided on the cylinder. In the rebound stopper structure of the damper capable of pinching the rebound stopper between the rebound stopper and the piston rod, an annular gap is provided between the inner periphery of the rebound stopper and the outer periphery of the piston rod, and notches are provided on upper and lower end faces of the rebound stopper. A damper rebound stopper structure. 2. The rebound stopper structure of a damper according to claim 1, wherein projections are provided at a plurality of circumferential positions on the inner periphery of the rebound stopper, and the rebound stopper makes the projections abut on a piston rod to form an annular gap. 3. The cross-sectional area of the notch provided on the upper and lower end faces of the rebound stopper is set larger than the cross-sectional area of an annular gap provided between the rebound stopper and the outer periphery of the piston rod. Damper rebound stopper structure.