JP3679223B2 - Bump stopper of hydraulic shock absorber - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic shock absorber that is attached to an end face of a cylinder of a hydraulic shock absorber and a bumper bar attached to the piston rod contacts when the piston rod of the hydraulic shock absorber is displaced maximum in the contraction direction. Related to bump stopper.
[0002]
[Prior art]
As this type of bump stopper, for example, one disclosed in Japanese Utility Model Laid-Open No. 4-14835 has been developed.
[0003]
This bump stopper has a structure in which a cup-shaped member attached to the end face of the cylinder of the hydraulic shock absorber and a disk-shaped sheet member that directly contacts the bumper bar are joined by welding or the like. In the case of this bump stopper, the contact load of the bumper bar can be supported with a sufficient plate thickness obtained by overlapping the sheet member and the cup-shaped member, and the bumper bar can be received with a relatively large area on the upper surface of the sheet member. it can.
[0004]
[Problems to be solved by the invention]
However, since the conventional bump stopper has a configuration in which two members, ie, a cup-shaped member and a sheet member are joined, there is a problem that the number of parts is large and the manufacturing cost is high. Therefore, it is conceivable to press-mold a bump stopper having a sheet wall against which the bumper bar abuts and a cylindrical wall attached to the cylinder from a single plate material. However, in this case, the following another problem occurs. .
[0005]
(1) Since the outer peripheral edge of the seat wall tends to follow and deform when the cylindrical wall is bent, a sufficient contact area of the bumper bar on the seat wall cannot be obtained, and the bumper bar hits the seat wall. When it comes into contact, the lower end of the bumper bar is expanded and deformed radially outward due to the impact. Further, such an extended deformation of the bumper bar may lead to deterioration of the bumper bar itself, or loss of the bump stopper due to the holding of the cylindrical wall.
[0006]
(2) To ensure the strength and rigidity of the outer peripheral edge where the contact load of the bumper bar is concentrated, the thickness of the entire bump stopper is increased, resulting in an increase in weight and an increase in manufacturing costs. Invite.
[0007]
Accordingly, the present invention is intended to provide a bump stopper for a hydraulic shock absorber that can be manufactured at a lower cost without incurring the above problems.
[0008]
[Means for Solving the Problems]
As a means for solving the above-mentioned problems, the invention of claim 1 is characterized in that the bumper bar attached to the end face of the cylinder of the hydraulic shock absorber and attached to the piston rod of the hydraulic shock absorber is the maximum contraction of the piston rod. A bump stopper that abuts when displaced, a piston rod insertion hole formed in the center, a circular seat wall that abuts the bumper bar on the upper surface, and a cylindrical wall that extends from the outer periphery of the seat wall in a substantially perpendicular direction The sheet wall and the cylindrical wall are formed by press-molding from a single plate material, and an outer annular protrusion projecting on the upper surface side is embossed on the outer peripheral edge of the sheet wall, and the sheet wall An inner annular protrusion protruding to the upper surface side is embossed on the inner peripheral edge of the outer peripheral edge of the bumper rubber, and the lower end of the bumper rubber is brought into contact with the upper surface between the outer annular protrusion and the inner annular protrusion. It is characterized in that was. The annular protrusion functions as a rib that increases the strength and rigidity of the outer peripheral edge of the seat wall, and suppresses expansion deformation in the radially outward direction of the lower end of the bumper bar when the bumper bar contacts the seat wall.
[0009]
According to a second aspect of the present invention, the outer peripheral edge portion of the seat wall according to the first aspect of the invention is formed so as to project outward in the radial direction 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 using an annular protrusion. In addition, it is possible to secure a larger area of the contact portion of the bumper bar on the seat wall by this overhang.
[0010]
In the invention of claim 3, the sheet wall and the cylindrical wall in the invention of claim 1 or 2 are press-molded from a rectangular plate material. Since the molding is performed from the rectangular plate material, the yield of the material is improved. When press-molding from a rectangular plate, the corner of the rectangular plate has a longer bending length than the side and is 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 sheet, 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 the protrusion.
[0011]
According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, at least one communication passage that communicates the piston rod insertion hole of the seat wall and the outer peripheral side space of the cylindrical wall through the annular protrusion is formed. I tried to do it. When the bumper bar comes into contact with the bump stopper, the air in the portion surrounded by the bumper bar 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 air is formed on the bump stopper side using the annular protrusion, it is not necessary to provide a special structure for discharging air on other members on the cylinder side.
[0012]
According to a fifth aspect of the present invention, in the third aspect of the invention, the linear protrusion connecting the piston rod insertion hole and the annular protrusion is embossed along the diagonal direction of the rectangular plate material. The linear protrusion functions as a rib that more strongly prevents the following bending of the portion corresponding to the corner on the seat wall.
[0013]
According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the linear protrusion constitutes a part of a communication path that communicates the piston rod insertion hole and the space on the outer peripheral side of the cylindrical wall. The linear protrusion has both a function of preventing the following bending of the portion corresponding to the corner on the seat wall and a function of discharging air.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described with reference to FIGS.
[0015]
FIG. 2 shows an automobile suspension including a hydraulic shock absorber 1 and a suspension spring 2. As shown in FIG. 2, the hydraulic shock absorber 1 has a so-called twin tube structure having an outer cylinder 3 and an inner cylinder 4. An eye bush 5 coupled to the wheel side is attached to the lower end of the outer cylinder 3, and a piston 6 is slidably accommodated in the inner cylinder 4.
[0016]
A piston rod 7 extending upward from the end surface of the outer cylinder 3 is coupled to the piston 6, and an upper spring seat 10 in a state where cushion rubbers 8 and 9 are superposed on the tip of the piston rod 7. Is inserted together with the bottomed cylindrical bumper retainer 11. The upper spring seat 10 is fixed to the piston rod 7 together with the bumper retainer 11 and the cushion rubbers 8 and 9 by a nut 12 screwed to the tip end portion of the piston rod 7, and the outer peripheral edge portion thereof is a bracket or the like. It is connected to a vehicle body panel (not shown) via 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.
[0017]
Further, a lower spring seat 13 is coupled 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.
[0018]
An annular locking projection 14 is formed slightly below the support surface 12 of the piston rod 7, and a bumper bar 15 for restricting the maximum displacement of the piston rod 7 in the contraction direction is formed on the locking projection 14. They are fitted and fixed by the bumper retainer 11. The bumper bar 15 has a main body portion 16 extending downwardly from the coupling portion with the piston rod 7 in a thick cylindrical shape. The outer periphery of the lower end of the main body portion 16 surrounds the outer periphery of the piston rod 7 and the outer cylinder 3. A bellows-like dust boot 17 is 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 portion 16, thereby adjusting the buffering performance of the main body portion 16.
[0019]
Incidentally, 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 to the upper end portion of the outer cylinder 3. Is fixed to the end surface thereof by caulking the upper end portion of the outer cylinder 3. 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 portion 16 of the bumper bar 15 abuts when the piston rod 7 is maximum displaced in the contraction direction.
[0020]
As shown in FIGS. 1 and 3 to 5, the bump stopper 21 includes a circular seat wall 23 in which a piston rod insertion hole 22 is formed at the center and the bumper bar 15 contacts the upper surface, and the seat wall 23. A cylindrical wall 24 extending in a substantially right angle direction from the outer periphery, and the sheet wall 23 and the cylindrical wall 24 are integrally formed by pressing from a single square plate material w (see FIG. 6A). Is formed.
[0021]
On the outer peripheral edge and inner peripheral edge of the seat wall 23, an outer annular protrusion 25 and an inner annular protrusion 26 are embossed so as to protrude upward, respectively. The four linear protrusions 27a, 27b, 27c, and 27d that connect the protrusion 25 and the inner annular protrusion 26 are similarly embossed so as to protrude upward. The linear protrusions 27a, 27b, 27c, and 27d are formed along the diagonal direction of the square plate material w.
[0022]
Further, as shown in FIG. 4, the outer peripheral edge portion of the seat wall 23 is formed to project outward in the radial direction with respect to the outer peripheral surface of the general portion of the cylindrical wall 24. The four corners 28 of the plate material w protrude maximum in the axial direction on the cylindrical wall 24, but the four corners 28 that protrude are deformed inward in the radial direction to form the outer peripheral surface of the outer cylinder 3. It is crimped. 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 fixed by caulking.
[0023]
Here, on the back side of the seat wall 23, the back surfaces of the linear protrusions 27a, 27b, 27c, and 27d in which the back surfaces of the inner annular protrusion 26 and the outer annular protrusion 25 that are annularly recessed are linearly recessed. Communicated by Therefore, the inner annular protrusion 26, the linear protrusions 27 a, 27 b, 27 c, 27 d and the outer peripheral protrusion 25 are formed between the outer cylinder 3 and the cylindrical wall 24 on the back surface side of the seat wall 23. Together with d, a communication passage 29 is formed which communicates the piston rod insertion hole 22 and the space portion on the outer peripheral side of the cylindrical wall 24.
[0024]
Further, the bump stopper 21 is manufactured by a procedure as shown in order in FIGS. 6 (a) to 6 (c).
[0025]
That is, first, as shown in FIG. 6B, each corner 28 is cut with respect to the square plate material w as shown in FIG. The protrusions 27a, 27b, 27c, 27d and the outer annular protrusion 25 are embossed. The corners 28 are cut in order to stably bring the corners 28 into contact with the outer cylinder 3 when the caulking is fixed to the outer cylinder 3. Then, the outer edge portion is bent by press molding so that the outer contour portion of the outer annular protrusion 25 is the bending center, and at this time, the cylindrical wall 24 is formed and the outer peripheral edge portion of the sheet wall 23 is formed. A bulge in the radially outward direction is formed, and each corner portion 28 is bent in the radially inward direction.
[0026]
If the outer annular protrusion 25 is previously embossed on the plate material w before the cylindrical wall 24 is bent on the outer periphery of the sheet wall 23 as described above, the outer annular protrusion 25 is formed into the cylindrical portion 24. The cylindrical wall 24 can be bent and formed relatively easily without causing deformation of the peripheral edge of the seat wall 23, and the outer peripheral edge of the seat wall 23 can be It can be easily projected outward in the radial direction. Further, when the cylindrical wall 24 is bent and formed on the outer periphery of the square plate material w, the portion corresponding to the corner portion 28 of the plate material 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 steel plate, but the following deformation is reliably suppressed because the outer annular protrusion 25 and the linear protrusions 27a, 27b, 27c, and 27d function as reinforcing ribs. . In particular, since the linear protrusions 27a, 27b, 27c, and 27d are formed along the diagonal direction of the plate material w, deformation of the portion corresponding to the corner portion 28 can be more effectively suppressed.
[0027]
In addition, 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 displaced to the maximum in the contraction direction in this state, the bumper bar 15 is placed on the upper surface of the sheet wall 23 of the bump stopper 21. The lower end of the main body portion 16 comes into contact, and the impact at that time is alleviated by the elasticity of the main body portion 16. At this time, the lower end of the main body portion 16 of the bumper bar 15 tends to expand radially outward, but the displacement of the lower end in the radially outward direction is reliably locked by the outer annular protrusion 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 substantial bumper bar contact portion is ensured sufficiently large on the seat wall 23 at this time. Has been. At this time, the contact load of the bumper bar 15 is concentrated on the outer peripheral edge portion of the seat wall 23, but the outer peripheral edge portion of the seat wall 23 is enhanced in strength and rigidity by the outer annular protrusion 25, so Even if a large load is applied, it does not cause deformation.
[0028]
Furthermore, when the piston rod 7 is displaced in the contracting direction and the main body portion 16 of the bumper bar 15 contacts the seat wall 23 of the bump stopper 21, a closed space surrounded by the main body portion 16 and the seat wall 23 is formed. The air in the closed space passes through the communication passage 29 formed by the inner annular protrusion 26 of the bump stopper 21, the linear protrusions 27 a, 27 b, 27 c, 27 d, and the back surfaces of the outer annular protrusion 25 and the gap d. It is discharged from the piston rod insertion hole 22 to the outer portion of the cylindrical wall 24. Therefore, 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 in the same manner by forming a passage in a member on the end face side of the outer cylinder 3, but as in this embodiment, the protrusion 25 functioning as a reinforcing rib or the like, When the communication path 29 is formed on the bump stopper 21 side using the 26, 27a, 27b, 27c, and 27d, it is possible to manufacture at a low cost because it is not necessary to perform special processing on other parts. Is possible.
[0029]
In the case of this embodiment, since the corner portion 28 pressed against the outer peripheral surface of the outer cylinder 3 is disposed on the extension of the linear protrusions 27a, 27b, 27c, 27d of the bump stopper 21, the bump stopper The communication passage 29 formed in 21 communicates with the piston rod insertion hole 22 and the space portion on the outer peripheral side of the cylindrical wall 24 in a bent shape, and therefore, from the outer peripheral side of the cylindrical wall 24 to the piston rod 7 side. Dust is difficult to enter.
[0030]
【The invention's effect】
As described above, according to the first aspect of the present invention, the outer annular protrusion protruding to the upper surface side is embossed on the outer peripheral edge portion of the seat wall, and the inner annular protrusion protruding to the upper surface side of the inner peripheral edge portion of the seat wall the embossed shaping, the outer annular protrusion and because of the upper surface between the inner annular projection is brought into contact with the lower end of the bumper rubber, the outer annular projection and the inner peripheral edge portion of the sheet walls by an inner annular projection Strength and rigidity can be increased, and expansion deformation in the radially inner and outer directions of the lower end of the bumper bar can be reliably suppressed. Therefore, it is possible to reliably support the contact load of the bumper bar without causing an increase in the plate thickness and the like, and it is possible to reliably prevent the deterioration due to the expansion deformation of the bumper bar and the removal of the bump stopper itself. Therefore, it becomes possible to press-mold from a single plate material without any problem, and it is possible to reduce the cost of the product.
[0031]
According to the second aspect of the present invention, the outer peripheral edge portion of the seat wall in the first aspect of the invention is formed so as to protrude radially outward with respect to the outer peripheral surface of the general portion of the cylindrical wall. It is possible to ensure a larger area of the bumper bar on the wall where the bumper bar comes into contact, and reliably prevent the lower end of the bumper bar from shifting when the bumper bar comes into contact.
[0032]
In the invention of claim 3, since the sheet wall and the cylindrical wall in the invention of claim 1 or 2 are press-molded from a rectangular plate material, a bending corresponding to a corner portion on the sheet wall is caused to follow. Therefore, the yield can be improved.
[0033]
According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, at least one communication passage that communicates the piston rod insertion hole of the seat wall and the outer peripheral side space of the cylindrical wall through the annular protrusion is formed. Therefore, the air in the portion surrounded by the bumper bar and the bump stopper can be surely discharged to the outside without providing a special structure on the cylinder side member.
[0034]
In the invention of claim 5, in the invention of claim 3, since the linear protrusion connecting the piston rod insertion hole and the annular protrusion is embossed along the diagonal direction of the rectangular plate material, Bending following the corner corresponding to the corner can be more reliably prevented by the linear protrusion together with the annular protrusion.
[0035]
According to a sixth aspect of the present invention, in the fifth aspect of the invention, the linear protrusion constitutes a part of the communication path that communicates the piston rod insertion hole and the space portion on the outer peripheral side of the cylindrical wall. The protruding portion can have a function to prevent the bending of the portion corresponding to the corner on the seat wall and a function for discharging air, which is lower than when each functional portion is formed separately. Manufacturing at a low cost is possible.
[Brief description of the drawings]
FIG. 1 is an enlarged cross-sectional view of a main part showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing the overall configuration of the embodiment.
FIG. 3 is a plan view of a bump stopper showing the same embodiment.
4 is a cross-sectional view taken along line AA of FIG. 3 showing the same embodiment.
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]
1 ... Hydraulic shock absorber 3 ... Outer cylinder (cylinder)
7 ... Piston rod 15 ... Bumper bar 21 ... Bump stopper 22 ... Piston insertion hole 23 ... Seat wall 24 ... Cylindrical wall 25 ... Outer annular projection
26 ... Inner annular protrusions 27a, 27b, 27c, 27d ... Linear protrusion 29 ... Communication path

Claims (6)

A bump stopper attached to the end face of the cylinder of the hydraulic shock absorber and attached to the piston rod of the hydraulic shock absorber is a bump stopper that contacts when the piston rod is fully contracted, and a piston rod insertion hole is formed in the center. Formed on the upper surface, and a cylindrical wall extending substantially perpendicularly from the outer periphery of the sheet wall, and the sheet wall and the cylindrical wall are pressed from a single plate material. In what is formed,
Embossing an outer annular protrusion protruding on the upper surface side on the outer peripheral edge of the seat wall, and embossing an inner annular protrusion protruding on the upper surface side on the inner peripheral edge of the sheet wall, the outer annular protrusion A bump stopper for a hydraulic shock absorber , wherein a lower end of the bumper rubber is brought into contact with an upper surface between the inner annular projection and the inner annular protrusion .   2. The bump stopper for a hydraulic shock absorber according to claim 1, wherein an outer peripheral edge portion of the sheet wall is formed so as to protrude radially outward with respect to an outer peripheral surface of a general portion of the cylindrical wall.   The bump stopper for a hydraulic shock absorber according to claim 1 or 2, wherein the sheet wall and the cylindrical wall are press-molded from a rectangular plate material.   The liquid according to any one of claims 1 to 3, wherein at least one communication passage is formed through the annular protrusion to communicate the piston rod insertion hole of the seat wall and the space portion on the outer peripheral side of the cylindrical wall. Bump stopper for pressure shock absorber.   The bump stopper for a hydraulic shock absorber according to claim 3, wherein a linear protrusion connecting the piston rod insertion hole and the annular protrusion is embossed along a diagonal direction of the rectangular plate member.   6. The bump stopper for a hydraulic shock absorber according to claim 5, wherein the linear protrusion constitutes 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. .

Images