JP2004225744A - Rebound rubber structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rebound rubber of urethane provided with annular grooves in an outer circumference capable of improving durability. <P>SOLUTION: In a rebound rubber 20 comprising urethane for a shock absorber 10, annular grooves 21 are provided at a plurality of positions apart from each other in an axial direction of the outer circumference. An end part of it on the abutting side to a rebound sheet 16 is set as a grooveless part 22 that is longer than an interval between the adjoining grooves. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rebound rubber structure of a hydraulic shock absorber.
[0002]
[Prior art]
A vehicle hydraulic shock absorber or the like has a piston rod inserted into a cylinder, includes a rebound rubber made of urethane 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. The rebound rubber is pinched between a rod guide provided in the cylinder and elastically deformed in the axial direction to absorb impact energy and reduce impact noise when the cylinder is extended.
[0003]
In this rebound rubber, as described in Patent Literature 1, annular grooves are provided at a plurality of positions on the outer periphery that are separated in the axial direction. The portion of the rebound rubber where the annular groove is provided is thin and easy to bend, softens the initial load characteristics when the piston rod is extended, and is excellent in absorbing impact energy when extended.
[0004]
[Patent Document 1]
Jiko 60-2360 (2 pages, Fig. 1)
[0005]
[Problems to be solved by the invention]
In Patent Literature 1, the annular grooves provided on the outer periphery of the rebound rubber are equally spaced in the axial direction, and depending on the length of the rebound rubber, the length of the grooveless portion at the end of the rebound rubber is adjacent to the annular groove. Shorter than the interval. In such a case, the strength of the end of the rebound rubber is weakened because it is made of urethane, and as the collision with the rebound seat repeats, the outer periphery expands, and there is a possibility that the rebound rubber may get over the rebound seat and get caught in the performance of the hydraulic shock absorber. Impair.
[0006]
An object of the present invention is to improve the durability of a urethane rebound rubber provided with an annular groove on the outer periphery.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 is a rebound rubber made of urethane of a shock absorber, wherein annular grooves are provided at a plurality of positions spaced apart in the axial direction on the outer periphery, and the end on the side contacting the rebound sheet is formed by the grooves and the grooves. This is a grooveless portion having a length longer than the interval between adjacent grooves.
[0008]
According to a second aspect of the present invention, in the first aspect of the present invention, the length of the non-groove portion is set to be at least twice as long as an interval between adjacent grooves.
[0009]
According to a third aspect of the present invention, in the rebound rubber made of urethane of the shock absorber, annular grooves are provided at a plurality of positions on the outer periphery that are spaced apart in the axial direction, and hard grooves are formed on the non-groove portions at the ends that come into contact with the rebound sheet. Is provided.
[0010]
According to a fourth aspect of the present invention, in the third aspect, the reinforcing ring is made of resin or metal.
[0011]
According to a fifth aspect of the present invention, in the third or fourth aspect, the reinforcing ring is further embedded at the time of forming the rebound rubber.
[0012]
According to a sixth aspect of the present invention, in the third or fourth aspect, the reinforcing ring is a C-ring, and is fitted in a fitting groove provided in a rebound rubber.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
1 is a schematic cross-sectional view showing a main part of the shock absorber according to the first embodiment, FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1, FIG. 3 shows a rebound rubber, (A) is a cross-sectional view, B) is an end view, FIG. 4 is a schematic sectional view showing a main part of the shock absorber of the second embodiment, and FIG. 5 is a sectional view showing a rebound rubber.
[0014]
(1st Embodiment) (FIGS. 1-3)
As shown in FIGS. 1 and 2, the shock absorber 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 moved vertically by a piston (not shown) fixed to the insertion end. Sections 14 and 15 (not shown) are defined. The shock absorber 10 receives the vehicle from the road surface by a damping mechanism configured by providing an extension-side flow path and a pressure-side flow path that connect the upper and lower oil chambers 14 and 15 to a piston, and providing a damping valve in those flow paths. It is possible to control the expansion and contraction vibration of the suspension spring for absorbing the shock.
[0015]
However, the shock absorber 10 has the rebound rubber 20 attached to the outer periphery of the piston rod 12 inside the cylinder 11 and, when the piston rod 12 is fully extended, the rebound seat 16 provided on the piston rod 12 and the cylinder 11. The rebound rubber 20 is sandwiched between the rod guide 13 and is elastically compressed and deformed in the axial direction to absorb the impact energy and extend the impact sound when extended.
[0016]
The rebound rubber 20 is a long cylindrical body made of urethane, and has a bellows shape in which annular grooves 21 are provided at a plurality of positions spaced at equal intervals a in the axial direction of the outer periphery of the cylinder to improve its spring property. I have. In other words, the rebound rubber 20 makes the thin portion provided with the annular groove 21 easy to bend, softens the initial load characteristics when the piston rod 12 is extended, and improves the absorption of impact energy when extended. The groove cross section of the annular groove 21 may be a V-shaped cross section, a trapezoidal cross section, a semicircular cross section, or the like.
[0017]
Further, the rebound rubber 20 has an annular groove 21 and a non-groove portion 22 having a length b longer than a space a adjacent to the annular groove 21 at the end in contact with the rebound sheet 16 (a <b). Preferably, the length b of the grooveless portion 22 is at least twice as long as the interval a between the adjacent annular grooves 21 (2a ≦ b). In the present embodiment, the outer periphery of the grooveless portion 22 is straight in the axial direction.
[0018]
In the rebound rubber 20, the interval a between the annular grooves 21 adjacent to each other is not limited to the interval a between all the sets of the annular grooves 21 adjacent to each other in the axial direction. May be different from each other at intervals a1, a2,. At this time, assuming that the maximum interval among the intervals a1, a2,... Is amax, the length b of the grooveless portion 22 is amax <b, more preferably 2 amax≦b.
[0019]
As shown in FIG. 3, the rebound rubber 20 is also deformed in the radial direction when the rebound rubber 20 is elastically compressed and deformed in the axial direction when the shock absorber 10 is fully extended to absorb the shock energy and reduce the impact sound. In order to prevent the hydraulic oil at the upper part of the rebound rubber 20 abutting against the inner circumference of the cylinder 11 from being trapped in this upper space and causing an oil lock state, the oil is locked between the inner circumference and the outer circumference of the piston rod 12. An annular gap 23 is provided, and concave portions 24A and 25A are provided on the upper and lower end surfaces, and the concave portions are cutouts 24 and 25. The recesses 24A and 25A may have 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, the notches 24 to 25 are preferably arranged such that the adjacent notches 24 (25) are arranged symmetrically in the circumferential direction between the adjacent notches 24 (25) (in this embodiment, equally spaced in the circumferential direction 4), but may be arbitrarily selected. The annular gap 23 and the notches 24, 25 are connected to each other to provide an escape path for hydraulic oil from the upper space of the rebound rubber 20.
[0020]
At this time, the rebound rubber 20 is provided with protrusions 26 at a plurality of inner circumferential positions (in this embodiment, four equally spaced positions), and the rebound rubber 20 makes the protrusions 26 contact the piston rod 12 and To form an annular gap 23.
[0021]
The rebound rubber 20 is configured such that the total cross-sectional area (flow area) A2 of each of the notches 24 and 25 provided on the upper and lower end surfaces is changed to the cross-sectional area (flow area) of the annular gap 23 between the notch 24 and the outer periphery of the piston rod 12. ) Set larger than A1.
[0022]
According to the present embodiment, the following operation and effect can be obtained.
(1) In the rebound rubber 20, the end on the side in contact with the rebound sheet 16 is a grooveless portion 22 having a length b longer than the interval a between adjacent annular grooves 21. Thereby, the strength of the rebound rubber 20 due to the annular groove 21 is not reduced to the end on the side that comes into contact with the rebound sheet 16, but the strength of the end is increased, and the outer periphery of the end is widened to prevent the rebound sheet 16 from entering the rebound sheet 16. To avoid. Therefore, durability can be improved while maintaining the soft load characteristics of the rebound rubber 20 made of urethane, and the performance of the shock absorber 10 can be stabilized.
[0023]
(2) The reinforcement b of the rebound rubber 20 described in (1) above is ensured by setting the length b of the grooveless portion 22 to be at least twice as long as the interval a between the annular grooves 21 adjacent to each other. Can be achieved.
[0024]
(3) Reinforcement of the rebound rubber 20 can be easily ensured only by adjusting the shape of the rebound rubber 20.
[0025]
In addition, according to the present embodiment, the following operational effects are also obtained.
{Circle around (1)} When the rebound rubber 20 is elastically compressed and deformed in the axial direction to reduce the absorption of shock energy and the shock noise when the shock absorber 10 is fully extended, the rebound rubber 20 also deforms in the radial direction and comes into contact with the inner periphery of the cylinder 11. Hydraulic oil at the upper part of the rebound rubber 20 passes through the notch 24 on the upper end face, passes through the annular gap 23 on the inner circumference, and further escapes from the notch 25 on the lower end face to the oil chamber 14 of the cylinder 11 to prevent the occurrence of an oil lock state. To avoid. Thereby, the bending of the rebound rubber 20 against the impact load is not suppressed, in other words, the spring constant of the rebound rubber 20 can be reduced, and the shock absorbing performance at the time of extension can be improved.
[0026]
{Circle around (2)} An annular clearance 23 is provided on the inner periphery of the rebound rubber 20 as an escape path for the hydraulic oil over the entire length of the rebound rubber 20, and the thickness of the meat does not become uneven in the circumferential direction, so that durability is improved. Can be improved.
[0027]
{Circle around (3)} By providing the notches 24 and 25 on the upper and lower end faces of the rebound rubber 20, the resistance to compressive deformation at the initial stage of elongation can be reduced (softened).
[0028]
{Circle around (4)} When the same notches 24 and 25 are provided on the upper and lower end surfaces of the rebound rubber 20, the direction of assembly to the piston rod 12 can be eliminated, and the assembly can be improved.
[0029]
(5) Protrusions 26 are provided at a plurality of circumferential positions on the inner periphery of the rebound rubber 20, and the rebound rubber 20 stabilizes the annular gap 23 by forming the annular gap 23 by contacting the projection 26 with the piston rod 12. Can be formed.
[0030]
{Circle around (6)} The rebound rubber 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 that does not freely move up and down on the outer periphery of the piston rod 12 can be easily formed.
[0031]
{Circle around (7)} The cross-sectional area A2 of the notches 24 and 25 provided on the upper and lower end surfaces of the rebound rubber 20 is made larger than the cross-sectional area A1 of the annular gap 23 provided between the notch 24 and the outer periphery of the piston rod 12. Therefore, the notches 24 and 25 serving as escape paths of the hydraulic oil from the upper part of the rebound rubber 20 in the above-mentioned (1) are not restricted, and the spring constant of the rebound rubber 20 is limited only to the spring characteristics of the constituent material of the rebound rubber 20. It is possible to stabilize the shock absorbing performance at the time of stretching.
[0032]
(2nd Embodiment) (FIG. 4, FIG. 5)
The difference between the second embodiment and the first embodiment is that the rebound rubber 20 is provided with a reinforcing ring 30 made of resin or metal and made of resin or metal, which is harder than urethane, on the non-grooved portion 22 at the end contacting the rebound sheet 16. It has been provided.
[0033]
The reinforcing ring 30 can be embedded when the rebound rubber 20 is formed. Alternatively, the reinforcing ring 30 may be a C-ring formed by cutting a part of the circumference by cutting a slit, and may be fitted into an annular fitting groove provided on the outer periphery of the rebound rubber 20.
[0034]
According to the present embodiment, the following operation and effect can be obtained.
(1) In the rebound rubber 20, a hard reinforcing ring 30 made of resin or metal is provided in the grooveless portion 22 at the end in contact with the rebound sheet 16. Thus, the strength of the rebound rubber 20 due to the annular groove 21 is not reduced by the end on the side that comes into contact with the rebound sheet 16, but the strength of the end is increased, and the outer periphery of the end is widened, so that the rebound sheet 16 is difficult to enter. And the reinforcing ring 30 does not directly contact the rebound seat 16 to generate abnormal noise. Therefore, durability can be improved while maintaining the soft load characteristics of the rebound rubber 20 made of urethane, and the performance of the shock absorber 10 can be stabilized.
[0035]
(2) Even when the long grooveless portion 22 cannot be formed at the end of the rebound rubber 20, the reinforcement of the rebound rubber 20 described in (1) above can be ensured.
[0036]
(3) The reinforcing ring 30 can be easily provided by embedding it when molding the rebound rubber 20.
[0037]
(4) The reinforcing ring 30 is a C-ring, and can be easily provided by being fitted into a fitting groove provided in the rebound rubber 20.
[0038]
In the rebound rubber 20 of the second embodiment, the length b of the grooveless portion 22 where the reinforcing ring 30 is provided may be equal to or less than the interval a between the adjacent annular grooves 21 (a ≧ b). However, as described in the first embodiment, the length b of the grooveless portion 22 where the reinforcing ring 30 is provided is set to a <b or 2a ≦ b as in the first embodiment. The operation and effect of (2) are also exhibited.
[0039]
As described above, the embodiment of the present invention has been described with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and there are design changes and the like that do not depart from the gist of the present invention. Are also included in the present invention. For example, the rebound rubber 20 does not necessarily require the provision of the annular gap 23, the notches 24, 25, and the protrusion 26.
[0040]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, durability can be improved in the urethane rebound rubber which provided the annular groove in the outer periphery.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view illustrating a main part of a shock absorber according to a first embodiment.
FIG. 2 is a sectional view taken along line II-II in FIG.
FIGS. 3A and 3B show a rebound rubber, wherein FIG. 3A is a sectional view and FIG. 3B is an end view.
FIG. 4 is a schematic sectional view showing a main part of a shock absorber according to a second embodiment.
FIG. 5 is a sectional view showing a rebound rubber.
[Explanation of symbols]
REFERENCE SIGNS LIST 10 shock absorber 16 rebound seat 20 rebound rubber 21 annular groove 22 grooveless portion 30 reinforcing ring

Claims (6)

In the rebound rubber made of urethane for the shock absorber,
Annular grooves are provided at a plurality of positions on the outer periphery that are separated in the axial direction,
A rebound rubber structure, characterized in that an end on the side contacting the rebound sheet is a grooveless portion having a length longer than the interval between adjacent ones of the grooves. 2. The rebound rubber structure according to claim 1, wherein the length of the non-groove portion is at least twice as long as an interval between adjacent grooves. 3. In the rebound rubber made of urethane for the shock absorber,
Annular grooves are provided at a plurality of positions on the outer periphery that are separated in the axial direction,
A rebound rubber structure, wherein a hard reinforcing ring is provided at a non-grooved portion at an end on a side abutting on a rebound sheet. The rebound rubber structure according to claim 3, wherein the reinforcing ring is made of resin or metal. The rebound rubber structure according to claim 3 or 4, wherein the reinforcing ring is embedded during molding of the rebound rubber. The rebound rubber structure according to claim 3 or 4, wherein the reinforcing ring is a C-ring, and is fitted in a fitting groove provided in the rebound rubber.

Images