JPH10299819A - Bump stopper of hydraulic pressure bumper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve rigidity of an outer peripheral edge part of a sheet wall by embossing and molding a ring projected part projected to the upper surface side on the outer peripheral edge part of the sheet wall of a bump stopper with which a bumper rubber installed on a piston rod makes contact at the time when the piston rod of a hydraulic pressure dumper is displaced to the maximum in the contracting direction. SOLUTION: An outer cylinder of a hydraulic pressure bumper is furnished with a rod guide 19 to guide sliding of a piston rod 7 on an upper end part and an oil seal 20 to close a sliding clearance of the piston rod 7 fitted and installed on it, and an upper end surface of the outer cylinder is covered with a bump stopper 21 with which a lower end of a bumper rubber 15 makes contact at the time when the piston rod 7 is moved and contracted to the maximum. This bump stopper 21 is formed of a circular sheet wall 23 with an upper surface of which the bumper rubber 15 makes contact and a cylindrical wall 24 extending in the roughly orthogonal direction from its outer periphery, but in this case, rigidity of the sheet wall 23 is improved by embossing and molding a ring projected part 25 on an inner and outer peripheral edge part of the sheet wall 23 so as to project it to the upper surface side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bumper bar mounted on an end surface of a cylinder of a hydraulic shock absorber and attached to the piston rod when the piston rod of the hydraulic shock absorber is maximally displaced in a contraction direction. The present invention relates to a bump stopper of a hydraulic shock absorber with which a contact is made.

[0002]

2. Description of the Related Art As this kind of bump stopper, for example, the one disclosed in Japanese Utility Model Laid-Open No. 4-14835 has been developed.

The bump stopper has a structure in which a cup-shaped member attached to an end surface of a cylinder of a hydraulic shock absorber and a disk-shaped sheet member directly contacting a bumper bar are joined by welding or the like. In the case of this bump stopper, the abutting load of the bump rubber can be supported by a sufficient thickness of the sheet member and the cup-shaped member overlapped, and the bump rubber can be received by the relatively large area of the upper surface of the sheet member. it can.

[0004]

However, since the conventional bump stopper has a structure in which the cup-shaped member and the sheet member are joined to each other, there is a problem that the number of components is large and the manufacturing cost is increased. is there. Therefore, it is conceivable to press-mold a bump stopper having a sheet wall that abuts the bump rubber and a cylindrical wall that is attached to the cylinder from a single plate material.
Another problem occurs as follows.

(1) Since the outer peripheral edge of the seat wall follows and is easily deformed when the cylindrical wall is bent, a sufficient contact area of the bumper bar on the seat wall cannot be obtained.
When the bump rubber contacts the seat wall, the lower end of the bump rubber expands and deforms radially outward due to the impact.
Such expansion deformation of the bump rubber may cause deterioration of the bump rubber itself and removal of the bump stopper due to the holding of the cylindrical wall.

(2) In order to secure the strength and rigidity of the seat surface, particularly the outer peripheral edge portion where the contact load of the bumper bar is concentrated, the entire thickness of the bump stopper is increased, resulting in an increase in weight and manufacturing. This leads to increased costs.

Accordingly, an object of the present invention is to provide a bump stopper of a hydraulic shock absorber which can be manufactured at lower cost without causing the above-mentioned problems.

[0008]

According to a first aspect of the present invention, there is provided a hydraulic shock absorber which is attached to an end face of a cylinder of a hydraulic shock absorber and is attached to a piston rod of the hydraulic shock absorber. Bump stopper is a bump stopper that abuts at the time of maximum contraction displacement of the piston rod,
A piston rod insertion hole is formed in the center portion, and a circular seat wall is formed on the upper surface to abut the bumper bar, and a cylindrical wall extending in a substantially perpendicular direction from the outer periphery of the seat wall. Is formed by press-molding a single plate material, and an annular protrusion projecting to the upper surface side is embossed on the outer peripheral edge of the sheet wall.
The annular projection functions as a rib that increases the strength and rigidity of the outer peripheral edge of the seat wall, and suppresses expansion deformation of the lower end of the bump rubber in the radially outward direction when the bump rubber comes into contact with the seat wall.

According to a second aspect of the present invention, the outer peripheral edge of the seat wall in the first aspect of the present invention is formed so as to project radially outward with respect to the outer peripheral surface of the general portion of the cylindrical wall.
The overhang of the outer peripheral edge of the seat wall can be easily formed by utilizing the annular projection. In addition, the overhang can ensure a larger area of the portion of the seat wall where the bumper bar contacts.

According to a third aspect of the present invention, the sheet wall and the cylindrical wall in the first or second aspect of the present invention are press-formed from a rectangular plate. Since it is formed from a rectangular plate, the yield of the material is improved. When press-forming from a rectangular plate, the corners of the rectangular plate are longer in bending length than the sides and are more easily deformed, so the portion corresponding to the corner on the sheet wall is a cylindrical wall. Although it is easy to bend following the bending of the seat, an annular protrusion is formed on the outer peripheral edge of the seat wall, and this annular protrusion functions as a rib. It can be blocked by protrusions.

According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, at least a communication path which communicates the piston rod insertion hole of the seat wall with the space on the outer peripheral side of the cylindrical wall through the annular projection is provided. One was formed. When the bump rubber comes into contact with the bump stopper, the air in the portion surrounded by the bump rubber and the bump stopper is discharged to the space on the outer peripheral side of the cylindrical wall through the piston rod insertion hole and the communication hole. Since the communication hole for discharging the air is formed on the bump stopper side by using the annular protrusion, it is not necessary to provide a special structure for discharging the air to another member on the cylinder side.

According to a fifth aspect of the present invention, in the third aspect of the invention, a linear projection connecting the piston rod insertion hole and the annular projection is formed along the diagonal direction of the rectangular plate material by embossing. The straight protrusion functions as a rib that more strongly prevents the following bending of the portion corresponding to the corner on the seat wall.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the linear projection forms a part of a communication path which communicates the piston rod insertion hole with the space on the outer peripheral side of the cylindrical wall. did. The straight protrusion has both the function of preventing the following bending of the portion corresponding to the corner on the seat wall and the function of discharging air.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to FIGS.
Explanation will be given based on FIG.

FIG. 2 shows an automobile suspension provided with a hydraulic shock absorber 1 and a suspension spring 2. As shown in FIG.
The inner cylinder 4 has a so-called twin tube structure. An eye bush 5 connected to the wheel side is attached to a lower end of the outer cylinder 3, and a piston 6 is slidably housed in the inner cylinder 4. I have.

A piston rod 7 extending upward from the end surface of the outer cylinder 3 is connected to the piston 6. The upper end of the piston rod 7 is provided with cushion rubbers 8 and 9 superposed vertically. A spring seat 10 is fitted together with a bottomed cylindrical bumper retainer 11. And the upper spring seat 10
Is a nut 12 screwed to the tip of the piston rod 7
With the bumper retainer 11 and the cushion rubber 8,
9, is fixed to the piston rod 7, and its outer peripheral edge is connected to a vehicle body panel (not shown) via a bracket or the like. A stepped support surface 12 is formed at the tip of the piston rod 7, and the bumper retainer 11 is supported on the support surface 12.

A lower spring seat 13 is connected to the outer peripheral surface of the outer cylinder 3, and the suspension spring 2 is interposed between the lower spring seat 13 and the upper spring seat 10.

An annular locking projection 14 is formed slightly below the supporting surface 12 of the piston rod 7.
A bumper bar 15 for restricting the maximum displacement of the piston rod 7 in the contraction direction is fitted to the locking projection 14 and fixed by the bumper retainer 11. The bump rubber 15 has a main body 16 extending downward from a connection portion with the piston rod 7 in a thick cylindrical shape, and a lower end outer periphery of the main body 16 surrounds the outer periphery of the piston rod 7 and the outer cylinder 3. Bellows-shaped dust boots 17
Are integrally extended. Further, a plurality of annular grooves 18 are formed along the axial direction on the inner surface side and the outer surface side of the main body 16, thereby adjusting the cushioning performance of the main body 16.

A rod guide 19 for guiding the sliding of the piston rod 7 and an oil seal 20 for sealing the sliding gap of the piston rod 7 are fitted on the upper end of the outer cylinder 3. These are fixed to the end surface of the outer cylinder 3 by caulking the upper end thereof. A bump stopper 21 according to the present invention is attached to the upper end surface of the outer cylinder 3 so that the lower end of the main body 16 of the bumper bar 15 abuts when the piston rod 7 is maximally displaced in the contracting direction.

This bump stopper 21 is shown in FIGS.
As shown in FIG. 5, the piston rod insertion hole 2
2 is provided on the upper surface thereof, a circular seat wall 23 in contact with the bumper bar 15 and a cylindrical wall 24 extending substantially perpendicularly from the outer periphery of the seat wall 23. Is a square plate material w (FIG. 6)
See (a). ) Is integrally formed by press molding.

At the outer peripheral edge and the inner peripheral edge of the seat wall 23,
The outer annular protrusion 25 and the inner annular protrusion 26 are embossed so as to protrude toward the upper surface, respectively, and the seat wall 23 is further provided with four connecting members for connecting the outer annular protrusion 25 and the inner annular protrusion 26 to each other. Linear projections 27a, 27b, 27c, 2
7d is similarly embossed so as to protrude to the upper surface side. The linear projections 27a, 27b, 27c, 27
d is formed along the diagonal direction of the square plate material w.

As shown in FIG. 4, the outer peripheral edge of the seat wall 23 is formed so as to protrude radially outward with respect to the outer peripheral surface of the general portion of the cylindrical wall 24. And the plate material w
The four corners 28 protrude maximally in the axial direction on the cylindrical wall 24. The four corners 28 that are projected are deformed radially inward, and are pressed against the outer peripheral surface of the outer cylinder 3. . Therefore, a predetermined gap d is formed between the outer peripheral surface of the outer cylinder 3 and the cylindrical wall 24 except for the four corner portions 28 which are fixed by caulking.

Here, on the back side of the seat wall 23,
An inner annular projection 26 and an outer annular projection 25 that are annularly depressed
Linear projections 27a, 27 whose back surfaces are recessed linearly
b, 27c, and 27d communicate with each other by the back surface portions.
Therefore, the inner annular projection 26, the linear projection 27
a, 27b, 27c, 27d, and the outer peripheral side protrusion 25
On the back side of the seat wall 23, together with the gap d between the outer cylinder 3 and the cylindrical wall 24, a communication passage 29 that communicates the piston rod insertion hole 22 with the space on the outer peripheral side of the cylindrical wall 24 is formed. I have.

The bump stopper 21 is manufactured according to the procedure shown in FIGS. 6A to 6C.

That is, first, as shown in FIG. 6B, each corner 28 is cut on a square plate material w as shown in FIG. 26,
The linear projections 27a, 27b, 27c, 27d and the outer annular projection 25 are respectively embossed. The corner 2
The cut 8 is performed in order to stably contact each corner 28 with the outer cylinder 3 at the time of caulking and fixing to the outer cylinder 3. After that, the outer edge is bent by press forming so that the outer contour of the outer annular projection 25 is set as the bending center, and at this time, the cylindrical wall 24 is formed, and the outer peripheral edge of the seat wall 23 is formed. Is formed in a radially outward direction, and each corner 28 is bent in a radially inward direction.

If the outer annular projection 25 is embossed on the plate w before the cylindrical wall 24 is formed on the outer periphery of the sheet wall 23 as described above, the outer annular projection 25 is Since it can be used as a bending fulcrum at the time of forming the cylindrical portion 24, the cylindrical wall 24 can be bent relatively easily without deforming the peripheral portion of the seat wall 23, and the outside of the seat wall 23 can be formed. The peripheral portion can be easily protruded radially outward. When the cylindrical wall 24 is formed by bending the outer periphery of the square plate member w, the portion corresponding to the corner 28 of the plate member w on the outer peripheral edge of the sheet wall 23 is more easily bent. It is conceivable that the deformation follows the bending of the outer ring-shaped projection 25 and the linear projections 27a, 27b, 2
Since 7c and 27d function as reinforcing ribs, they are reliably suppressed. In particular, the linear projections 27a, 27b, 27
Since c and 27d are formed along the diagonal direction of the plate material w, deformation of the portion corresponding to the corner 28 can be suppressed more effectively.

When the bump stopper 21 is attached to the end of the outer cylinder 3 and the piston rod 7 of the hydraulic shock absorber 1 is maximally displaced in the contracting direction in this state, the upper surface of the sheet wall 23 of the bump stopper 21 is moved. The lower end of the main body 16 of the bump rubber 15 is in contact with the bumper bar 15, and the elasticity of the main body 16 reduces the impact at that time. At this time, the lower end of the main body portion 16 of the bumper bar 15 tends to expand outward in the radial direction, but displacement of the lower end in the radial outer direction is reliably locked by the outer annular projection 25 of the seat wall 23.
Since the outer peripheral edge of the seat wall 23 is formed so as to protrude radially outward with respect to the outer cylinder 3, a substantially large bump rubber contact portion is secured on the seat wall 23 at this time. Have been. At this time, the contact load of the bump rubber 15 is concentrated on the outer peripheral edge of the seat wall 23. However, since the outer peripheral edge of the seat wall 23 is enhanced in strength and rigidity by the outer annular protrusion 25, Even under heavy loads, it does not cause deformation.

Furthermore, when the piston rod 7 is displaced in the contracting direction and the main body 16 of the bump rubber 15 comes into contact with the seat wall 23 of the bump stopper 21, a closed space surrounded by the main body 16 and the seat wall 23 is formed. However, the air in the closed space is generated by the inner annular projection 2 of the bump stopper 21.
6, through the communication path 29 formed by the gap d and the back surface of the linear projections 27a, 27b, 27c, 27d and the outer annular projection 25, and from the piston rod insertion hole 22 to the cylindrical wall 24.
It is discharged to the outside part of. Therefore, the high-pressure air generated in the closed space does not act on the end surface of the outer cylinder 3. The air in the closed space can be discharged similarly by forming a passage in the member on the end face side of the outer cylinder 3. However, as in this embodiment, the protrusions 25, which function as reinforcing ribs and the like, are used. 26, 27a, 27
When the communication path 29 is formed on the bump stopper 21 side by using b, 27c, and 27d, it is possible to manufacture at low cost because there is no need to perform special processing on other parts.

In the case of this embodiment, a corner 28 which is pressed against the outer peripheral surface of the outer cylinder 3 is arranged on the extension of the linear projections 27a, 27b, 27c, 27d of the bump stopper 21. The communication passage 29 formed in the bump stopper 21 communicates the piston rod insertion hole 22 with the space on the outer peripheral side of the cylindrical wall 24 in a bent shape, and therefore, the piston rod 7 from the outer peripheral side of the cylindrical wall 24. It is difficult for dust and the like to enter the side.

[0030]

As described above, according to the first aspect of the present invention, the annular projection protruding toward the upper surface is embossed on the outer peripheral edge of the seat wall. And the rigidity of the bumper bar can be enhanced, and the expansion deformation of the lower end of the bumper bar in the radially outward direction can be reliably suppressed. Therefore, it is possible to reliably support the contact load of the bump rubber without increasing the plate thickness and the like, and it is possible to reliably prevent the bump rubber from being deteriorated due to the expansion deformation and the bump stopper itself from coming off. Therefore, it is possible to press-mold a single plate material without any trouble, and it is possible to reduce the cost of the product.

According to the second aspect of the present invention, the outer peripheral edge of the seat wall in the first aspect of the present invention is formed so as to project radially outward with respect to the outer peripheral surface of the general portion of the cylindrical wall. The overhang secures a larger area of the bumper bar on the seat wall in contact with the bumper bar, and can reliably prevent the lower end of the bumper bar from shifting when the bumper bar contacts.

According to a third aspect of the present invention, since the sheet wall and the cylindrical wall in the first or second aspect of the present invention are press-formed from a rectangular plate material, a portion corresponding to a corner on the sheet wall follows the bending. The yield can be improved without inviting the like.

According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, at least a communication path for communicating the piston rod insertion hole of the seat wall with the space on the outer peripheral side of the cylindrical wall through the annular projection is provided. Since one is formed, the air in the portion surrounded by the bump rubber and the bump stopper can be reliably discharged to the outside when the bump rubber is abutted without providing a special structure on the cylinder side member.

According to a fifth aspect of the present invention, in the third aspect of the present invention, a linear projection connecting the piston rod insertion hole and the annular projection is formed along the diagonal direction of the rectangular plate material by embossing. The follow-up bending of the portion corresponding to the corner on the wall can be more reliably prevented by the linear projection together with the annular projection.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the linear projection constitutes a part of a communication path which communicates the piston rod insertion hole with the space on the outer peripheral side of the cylindrical wall. As a result, the linear projection can be provided with the function of preventing the following bending of the portion corresponding to the corner on the seat wall and the function of discharging the air, compared with a case where each functional part is formed separately. Therefore, it can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a main part showing one embodiment of the present invention.

FIG. 2 is a sectional view showing the overall configuration of the embodiment.

FIG. 3 is a plan view of a bump stopper according to the embodiment.

FIG. 4 is a sectional view of the embodiment, taken along line AA of FIG. 3;

FIG. 5 is a rear view of the bump stopper showing the embodiment.

FIG. 6 is a perspective view showing the manufacturing process of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hydraulic shock absorber, 3 ... Outer cylinder (cylinder), 7 ... Piston rod, 15 ... Bump rubber, 21 ... Bump stopper, 22 ... Piston insertion hole, 23 ... Seat wall, 24 ... Cylindrical wall, 25 ... Outer annular protrusion Parts (annular protrusions), 27a, 27b, 27c, 27d ... linear protrusions, 29 ... communication passages.

Claims (6)

[Claims] A bump stopper, which is attached to an end surface of a cylinder of a hydraulic shock absorber and is attached to a piston rod of the hydraulic shock absorber, is a bump stopper that abuts when the piston rod is maximally contracted and displaced. A piston seat is formed on the upper surface of the seat wall, and the upper surface of the seat wall has a circular seat wall that abuts the bumper bar, and a cylindrical wall extending substantially perpendicularly from the outer periphery of the seat wall. A bump stopper for a hydraulic shock absorber, which is formed by press-forming a sheet material, wherein an annular protrusion protruding toward the upper surface is embossed on an outer peripheral edge of the sheet wall. 2. The hydraulic shock absorber according to claim 1, wherein an outer peripheral edge of the seat wall is formed so as to project radially outward with respect to an outer peripheral surface of a general portion of the cylindrical wall. Bump stopper. 3. The bump stopper according to claim 1, wherein the sheet wall and the cylindrical wall are formed by pressing a rectangular plate. 4. The communication device according to claim 1, wherein at least one communication passage is formed through said annular protrusion to communicate the piston rod insertion hole of the seat wall with the space on the outer peripheral side of the cylindrical wall. A bump stopper for a hydraulic shock absorber according to any of the above items. 5. The bump of a hydraulic shock absorber according to claim 3, wherein a linear projection connecting the piston rod insertion hole and the annular projection is formed along the diagonal direction of the rectangular plate material. Stopper. 6. The hydraulic pressure according to claim 5, wherein the linear projection forms a part of a communication path that connects the piston rod insertion hole and a space on the outer peripheral side of the cylindrical wall. Bump stopper for shock absorber.