JP2002310216A - Dust cover structure of hydraulic buffer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the end of a dust cover from abutting to a spring seat stably and securely while facilitating assembly of the dust cover. SOLUTION: The dust cover 30 in the dust cover structure of the hydraulic buffer 10 comprises a bellows part 31 and a straight part 32 continued from the bellows part 31. The inner side of the bellows part 31 is made to abut to a bellows holder 33 mounted in the middle between the end part of a damper tube 11 and a lower spring seat 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dust cover structure for a hydraulic shock absorber.

[0002]

2. Description of the Related Art The dust cover structure of a hydraulic shock absorber has a damper tube and a piston rod as described in Japanese Utility Model Application Laid-Open No. 62-86215, and is provided on a lower spring seat and a piston rod provided on the damper tube. In addition, a dust cover is provided between the upper spring seat and a suspension spring, and covers a piston rod penetrating portion at the end of the damper tube.

[0003] In the prior art, a dust cover is provided with a bellows portion abutting a bump cap provided at an upper end portion of a damper tube, and extends downward from a lower end portion of the bellows portion so as to face a lower spring seat with a predetermined gap. And a straight part. Since the lower end of the dust cover is not attached to the side of the damper tube, assemblability can be improved.
Further, the straight portion constituting the lower end of the dust cover is prevented from abutting on the lower spring seat to prevent the painted surface of the lower spring seat from peeling and rusting.

[0004]

When the piston rod is contracted, the bellows portion of the dust cover is interposed between the bump rubber provided on the piston rod and the bump cap provided on the damper tube to restrict the contracted end. The bellows may be damaged.

When the piston rod is contracted, the bellows portion is pushed out around the bump cap by the bump rubber, and the straight portion forming the lower end of the dust cover comes into contact with the lower spring seat, and the painted surface of the lower spring seat is exposed. Peeling and rust may occur. In addition, the bellows extruded around the bump cap hits the outer edge of the bump cap when the piston rod extends, and tries to restore the original state, which causes abnormal noise and impairs the durability of the dust cover.

SUMMARY OF THE INVENTION It is an object of the present invention to stably and reliably prevent an end of a dust cover from contacting a spring seat while improving the assemblability of the dust cover.

[0007]

The invention according to claim 1 has a damper tube and a piston rod, and a suspension spring is provided between a lower spring seat provided on the damper tube and an upper spring seat provided on the piston rod. Interposed,
In a dust cover structure of a hydraulic shock absorber including a dust cover covering a piston rod penetration portion at an end of a damper tube, the dust cover is attached to a piston rod and has an inner diameter larger than an outer diameter of the damper tube. A bellows portion, and a straight portion provided continuously with the bellows portion and having an inner diameter equal to or larger than the outer diameter of the bellows portion, and the inner diameter of the bellows portion of the dust cover is set to be lower than the end portion of the damper tube. The bellows support is provided in the middle of the spring seat.

According to a second aspect of the present invention, in addition to the first aspect, the straight portion of the dust cover is located at a position surrounding the bellows support even when the piston rod is fully extended.

According to a third aspect of the present invention, in addition to the second aspect, the straight portion of the dust cover is guided in contact with the outer periphery of the bellows receiver.

According to a fourth aspect of the present invention, in the third aspect of the present invention, a projection is provided inside the end of the straight portion of the dust cover.

According to a fifth aspect of the present invention, the dust cover is further formed integrally with the bump rubber in the first aspect of the present invention.

According to a sixth aspect of the present invention, in the first aspect of the present invention, the bellows support is formed integrally with the bump cap.

[0013]

According to the first aspect of the present invention, the following effects are obtained. Since the straight portion on the lower end portion side of the dust cover is not attached to the damper tube side, assemblability can be improved.

The bellows part on the upper end side of the dust cover is attached to the piston rod, and even if the upper end of the dust cover descends when the piston rod contracts, the bellows part is provided in the middle of the damper tube. As a result, the straight portion below the bellows portion does not make a downward stroke, and a constant gap can be secured between the straight portion and the lower spring seat to prevent contact with the lower spring seat. Thereby, peeling and rusting of the painted surface of the lower spring seat can be prevented.

The bellows portion of the dust cover abuts and is supported by the bellows receiver in the middle of the damper tube. Therefore, when the bump rubber provided on the piston rod abuts on the bump cap provided on the damper tube at the contracted end of the piston rod, the bellows portion is not affected by the bump rubber and is not damaged.

When the piston rod is contracted, the bellows portion is not pushed out around the bellows receiver by the bump rubber. Therefore, the above-described situation in which the straight portion of the dust cover does not contact the lower spring seat is stably maintained.
In addition, since the bellows portion is stably supported by the bellows receiver, there is no possibility of causing any inconvenience due to being detached from the bellows receiver.

According to the second aspect of the invention, the following operations are provided. The straight portion of the dust cover is set at a position surrounding the bellows support even when the piston rod is fully extended. Therefore,
Even when the piston rod is fully extended, the dust cover covers the dust tube, so that the piston rod and the seal portion can be reliably protected from dust such as water and mud. Also, when the piston rod is fully extended, the dust cover does not come off from the bellows support, and when the piston rod contracts, the dust cover does not catch on the bellows support and fall down, preventing interference with the suspension spring and preventing damage. , Smooth stroke.

According to the third aspect of the invention, the following operations are provided. The straight part of the dust cover is guided in contact with the outer periphery of the bellows receiver. Therefore, the straight portion is centered on the bellows support, preventing interference with the suspension spring, preventing breakage, and enabling smooth stroke.

According to the fourth aspect of the present invention, the following operations are provided. A protrusion is provided inside the end of the straight portion of the dust cover. Therefore, even when the straight portion of the dust cover is likely to come off from the bellows receiver when the piston rod is fully extended, the protrusion engages with the outer periphery of the bellows receiver to reliably prevent this coming off.

According to the fifth aspect of the invention, the following effects are obtained. Since the dust cover is integrally molded with the bump rubber, the number of parts is reduced and the assemblability is improved.

According to the sixth aspect of the present invention, the following operations are provided. Since the bellows support is integrally formed with the bump cap, the number of parts is reduced, and the assemblability is improved.

[0022]

FIG. 1 is a sectional view showing a hydraulic shock absorber according to a first embodiment, in which a right half shows an extended state, a left half shows a contracted state, and FIG. 2 shows a bellows. FIG. 3 is a cross-sectional view showing a bump cap provided with a support, and FIG. 3 is a cross-sectional view showing a hydraulic shock absorber according to a second embodiment, in which the right half shows an extended state and the left half shows a contracted state. is there.

(First Embodiment) (FIGS. 1 and 2) As shown in FIG. 1, a hydraulic shock absorber 10 includes a damper tube 1
1, a piston rod 12 and a suspension spring 13,
A lower spring seat 14 is attached to an outer periphery of an intermediate portion of the damper tube 11, an upper pulling seat 15 is attached to an upper end of the piston rod 12, and a suspension spring 13 is interposed between the spring seats 14, 15. ing. 15A is a spring seat rubber.

The hydraulic shock absorber 10 includes an axle-side mounting portion 16 at the lower end of the damper tube 11, and a piston rod 12.
The vehicle body-side mounting portion 17 is provided on the upper spring seat 15 attached to the vehicle body, and a mounting bolt 18 is provided on the vehicle body-side mounting portion 17. The hydraulic shock absorber 10 is provided with the suspension spring 1.
3 absorbs the impact from the road surface and the damper tube 11
The suspension spring 1 is provided by a built-in damping device (not shown).
Suppress the stretching vibration of 3.

The hydraulic shock absorber 10 includes a piston rod 1
The seats 22, 23 and the restraining cap 24 are positioned by the joint collar 21 attached to the upper end of the mounting rubber 2, and mount rubbers 25A, 25B are provided between the seats 22, 23. With the upper spring seat 15 held therebetween, the piston rod 1
A mounting nut 26 is screwed onto the upper end of the second.

The hydraulic shock absorber 10 includes a bump rubber 27 which is firmly hugged around the outer periphery of the piston rod 12 and a mount rubber 25 via a restraining cap 24.
A and 25B support the back, and a bump cap 28 (FIG. 2) is attached to the upper end of the damper tube 11. When the piston rod 12 is contracted most, the hydraulic shock absorber 10 abuts the bump rubber 27 against the bump cap 28 to regulate the contracted end thereof. The restraining cap 24 regulates the deformation of the bump rubber 27 in the radial direction to achieve the spring constant of the bump rubber 27.

However, the hydraulic shock absorber 10 includes the dust cover 30 that covers the periphery of the seal portion through which the piston rod 12 penetrates at the upper end of the damper tube 11 to which the bump cap 28 is attached. Dust cover 30
Covers the upper end of the damper tube 11 and protects the piston rod 12 and the seal from dust such as water and mud.

The dust cover 30 is integrally formed from the bump rubber 27 and extends downward from an overhang portion 27B that projects from the bump rubber 28 to the lower portion outside the abutment surface 27A with the bump cap 28.

The dust cover 30 is connected to the projecting portion 27B of the bump rubber 27 and has a bellows portion 31 having an inner diameter larger than the outer diameter of the damper tube 11, and is provided continuously with the lower end portion of the bellows portion 31. And a straight portion 32 having an inner diameter equal to or greater than the outer diameter of the portion 31.

The dust cover 30 is provided on the piston rod 12
At the time of contraction, the inside (lowermost portion) of the bellows portion 31 is brought into contact with a bellows support 33 provided between the upper end portion of the damper tube 11 and the lower spring seat 14 (the left half portion in FIG. 1). With the bellows part 31 in contact with the bellows receiver 33, the straight part 3
The lower end of 2 opposes the lower spring seat 14 via a certain gap. This prevents the dust cover 30 from hitting the lower spring seat 14 and prevents the painted surface of the lower spring seat 14 from peeling and rusting.

In the present embodiment, the bellows support 33 is
The bump cap 28 is integrally formed. As shown in FIG. 2, the bump cap 28 has a cylindrical shape with a top and a cylindrical portion 28 </ b> A attached to the damper tube 11.
B is welded with an abutment plate 28C with the bump rubber 27 to form a flange portion 28D which extends radially outward at the lower end of the cylindrical portion 28A to form an annularly continuous flange portion 28B. It is.

In the dust cover 30, even when the piston rod 12 is fully extended, the straight portion 32
Is set so as to surround the bellows receiver 33 (the right half of FIG. 1). Further, the dust cover 30 is set such that the straight portion 32 is guided in contact with the outer periphery of the bellows support 33.

According to the present embodiment, the following operations are provided. Since the straight portion 32 on the lower end side of the dust cover 30 is not attached to the damper tube 11, the assemblability can be improved.

The bellows portion 31 on the upper end side of the dust cover 30 is attached to the piston rod 12 so that when the piston rod 12 is contracted, the bellows portion 31 is moved even if the upper end portion of the dust cover 30 moves downward. The straight portion 32 below the bellows portion 31 abuts against the bellows receiver 33 provided in the middle of the damper tube 11, and as a result, a certain gap is secured between the straight portion 32 and the lower spring seat 14 without lowering stroke. Contact with the sheet 14 can be prevented. Thereby, peeling and rusting of the painted surface of the lower spring seat 14 can be prevented.

The bellows portion 31 of the dust cover 30 is supported in contact with a bellows support 33 in the middle of the damper tube 11. Accordingly, even when the bump rubber 27 provided on the piston rod 12 abuts on the bump cap 28 provided on the damper tube 11 at the contracted end of the piston rod 12, the bellows 31 may be affected by the bump rubber 27. No damage.

When the piston rod 12 contracts, the bellows portion 31 is not pushed out around the bellows receiver 33 by the bump rubber 27. Accordingly, the above-described situation in which the straight portion 32 of the dust cover 30 does not contact the lower spring seat 14 is stably maintained. Further, since the bellows portion 31 is stably supported by the bellows support 33, there is no possibility that the bellows portion 31 may be inconvenient due to being detached from the bellows support 33.

The straight portion 32 of the dust cover 30 is set at a position surrounding the bellows support 33 even when the piston rod 12 is fully extended. Therefore, even when the piston rod 12 is fully extended, the dust cover 30 covers the dust tube, and the piston rod 12 and the seal portion can be reliably protected from dust such as water and mud. Also, when the piston rod 12 is fully extended, the dust cover 30 does not come off from the bellows support 33, and when the piston rod 12 contracts, the dust cover 30 is not caught by the bellows support 33 and falls down. To prevent breakage and smooth stroke.

The straight portion 32 of the dust cover 30 is guided in contact with the outer periphery of the bellows support 33. Therefore, the straight portion 32 is centered on the bellows support 33, preventing interference with the suspension spring 13, preventing breakage, and enabling smooth stroke.

Since the dust cover 30 is integrally formed with the bump rubber 27, the number of parts is reduced and the assembling property is improved.

Since the bellows receiver 33 is formed integrally with the bump cap 28, the number of parts is reduced and the assembling property is improved.

Second Embodiment (FIG. 3) The hydraulic shock absorber 10 of the second embodiment is different from the hydraulic shock absorber 10 of the first embodiment, as shown in FIG. That is, the projection 40 is provided inside (inner circumference) of the lower end of the projection 32. Even when the straight portion 32 of the dust cover 30 is likely to come off the bellows support 33 when the piston rod 12 is fully extended, the projection 40 is engaged with the outer periphery of the bellows support 33 to reliably prevent the coming off.

The projection 40 of the straight portion 32 has a tapered surface 41 whose diameter gradually decreases from the lower end of the straight portion 32.
And the step surface 4 following the smallest diameter portion (upper end portion) of the tapered surface 41
The straight portion 32 is elastically expanded and deformed by the tapered surface 41 pushed into the outer edge of the bellows support 33, and the bellows support 33 is provided. Passes smoothly), step surface 4
2, the ability to prevent detachment due to engagement with the bellows receiver 33 after assembly is improved.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and the design may be changed without departing from the scope of the present invention. The present invention is included in the present invention. For example, the dust cover of the present invention is not limited to the one integrally formed with the bump rubber, the one separately attached to the bump rubber, the one attached to the bump rubber, the one integrally formed with the restraining cap, and the restraining cap. May be attached separately to the restraining cap, or may be integrally formed with the seat rubber of the upper spring seat.

Further, the bellows support of the present invention is not limited to the one integrally formed with the bump cap, but may be formed separately from the bump cap and attached to the bump cap or the damper tube, or overhanged on the damper tube itself. What is done may be. A bellows receiver may be integrally formed with a resin bump cap.

[0045]

As described above, according to the present invention, the end of the dust cover can be stably and reliably prevented from coming into contact with the spring seat while the assemblability of the dust cover is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a hydraulic shock absorber according to a first embodiment, in which a right half shows an extended state and a left half shows a contracted state.

FIG. 2 is a sectional view showing a bump cap provided with a bellows support.

FIG. 3 is a cross-sectional view illustrating a hydraulic shock absorber according to a second embodiment, in which a right half is in an extended state and a left half is in a contracted state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Hydraulic shock absorber 11 Damper tube 12 Piston rod 13 Suspension spring 14 Lower spring seat 15 Upper spring seat 27 Bump rubber 28 Bump cap 30 Dust cover 31 Bellows 32 Straight part 33 Bellows receiver 40 Projection

Claims (6)

[Claims] 1. A piston at an end of a damper tube having a damper tube and a piston rod, a suspension spring interposed between a lower spring seat provided on the damper tube and an upper spring seat provided on the piston rod. A dust cover structure for a hydraulic shock absorber comprising a dust cover covering a rod penetrating part, wherein the dust cover is attached to a piston rod side and has an inner diameter larger than an outer diameter of a damper tube; And a straight portion having an inner diameter equal to or greater than the outer diameter of the bellows portion, the inner diameter of the bellows portion of the dust cover being provided between the end of the damper tube and the lower spring seat. A dust cover structure for a hydraulic shock absorber, wherein the dust cover structure is in contact with a bellows receiver. 2. The dust cover structure for a hydraulic shock absorber according to claim 1, wherein the straight portion of the dust cover is located at a position surrounding the bellows support even when the piston rod is fully extended. 3. The dust cover structure for a hydraulic shock absorber according to claim 2, wherein the straight portion of the dust cover is guided in contact with the outer periphery of the bellows receiver. 4. The dust cover structure for a hydraulic shock absorber according to claim 3, wherein a projection is provided inside an end of the straight portion of the dust cover. 5. The dust cover structure for a hydraulic shock absorber according to claim 1, wherein said dust cover is formed integrally with a bump rubber. 6. The dust cover structure for a hydraulic shock absorber according to claim 1, wherein said bellows support is integrally formed with a bump cap.