JP2002235786A - Hydraulic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve comfortableness by changing an oil lock load at the most compression time in a continuously variable manner while reducing a cost by simplifying a shock absorbing structure at the most compression time. SOLUTION: A hydraulic shock absorber 10 is provided with a suspension spring 23 which has such a pitch between element wires that it comes close to each other through a slight clearance that can avoid a metal contact between the element wires at the most compression time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic shock absorber such as a front fork which is interposed between a vehicle body such as a motorcycle and wheels and absorbs a shock from a road surface.

[0002]

2. Description of the Related Art Conventionally, as a hydraulic shock absorber,
As described in Japanese Patent Publication No. 06, an inner tube attached to the wheel side is slidably fitted to an outer tube connected to the vehicle body side, and a damper cylinder is erected inside the outer tube, and is inserted inside the inner tube. Raise the piston rod, insert the piston rod into the damper cylinder, provide a damping force generator on the piston provided on the piston rod, and, at the outer periphery of the damper cylinder, between the outer tube and the inner tube, In some cases, a suspension spring along the inner periphery of the inner tube is interposed between a spring receiver on the outer periphery of the damper cylinder and the bottom of the inner tube.

In the prior art, as a buffer structure at the time of maximum compression, an oil lock collar at the lower end of the damper cylinder can be fitted to an oil lock collar at the lower end of the inner tube, so that the oil compressed between the two is compressed. As a result, an oil lock action is generated, and the bottom of the hydraulic shock absorber is prevented.

[0004]

However, in the prior art, two oil lock collars are used as a buffer structure at the time of maximum compression, so that the number of parts increases and the cost increases. It is necessary to form a small gap at the time of fitting, which increases the processing cost.

[0005] It is an object of the present invention to simplify the buffer structure at the time of maximum compression to reduce the cost, and to improve the riding comfort by continuously changing the oil lock load at the time of maximum compression.

[0006]

According to a first aspect of the present invention, an inner tube attached to a wheel is slidably fitted to an outer tube connected to a vehicle body, and a damper cylinder is erected inside the outer tube. At the same time, a piston rod is erected inside the inner tube, the piston rod is inserted into the damper cylinder, a damping force generator is provided on the piston provided on the piston rod, and the outer tube and the inner tube An oil reservoir having an upper portion as a gas chamber is formed therebetween, and a hydraulic shock absorber in which a suspension spring along an inner periphery of the inner tube is interposed between a spring receiver on the outer periphery of the damper cylinder and a bottom portion of the inner tube. A state in which the suspension springs are in close proximity to each other via a small gap that can avoid metal contact between the wires at the time of maximum compression. The size of that is obtained by the so provided with a wire pitch.

According to a second aspect of the present invention, in the first aspect of the invention, the oil reservoir is further divided into a lower portion and an upper portion by the spring receiver, and an orifice communicating the lower oil reservoir and the upper oil reservoir is provided in the spring receiver. It is provided in.

According to a third aspect of the present invention, in the second aspect of the present invention, the orifice further includes a valve for adjusting a flow rate of oil from the lower oil reservoir to the upper oil reservoir.

[0009]

According to the first aspect of the present invention, the following effects are obtained. The gap between the strands of the suspension spring gradually decreases with compression, and at the time of maximum compression, the suspension springs come close to each other with a small gap only to avoid metal contact, and become substantially in close contact. For this reason, at the time of compression, when the oil corresponding to the entering volume of the damper cylinder that enters the oil reservoir in the inner tube is pushed upward through the flow path between the wires of the suspension spring, at the time of maximum compression, The flow path becomes a small gap as described above, and the pressure in the lower oil reservoir (oil lock load) is greatly increased to cause an oil lock effect, thereby preventing the hydraulic shock absorber from bottoming out.

The above-described buffer structure at the time of maximum compression can be simplified simply by changing the pitch between the strands of the suspension spring, and the cost can be reduced.

The pitch between the strands of the suspension spring gradually decreases throughout the entire compression process, so that the oil lock load at the time of the maximum compression can be smoothly changed steplessly, and the riding comfort can be improved. .

According to the second and third aspects of the present invention, the following effects are obtained. The orifice provided in the spring receiver of the suspension spring communicates the lower oil reservoir with the upper oil reservoir in parallel with the flow path between the wires of the suspension spring. Therefore, the orifice hole diameter,
Alternatively, the oil lock characteristics at the time of the maximum compression can be easily adjusted by adjusting the plate thickness and the number of valves provided in the orifice.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view showing a main part of a hydraulic shock absorber of the first embodiment at the time of maximum extension, and FIG. 2 is a main part of the hydraulic shock absorber of the first embodiment at the time of maximum compression. The schematic diagram, FIG.
FIG. 4 is a schematic view showing a main part of the hydraulic shock absorber according to the embodiment, and FIG.
It is a schematic diagram which shows the principal part of the hydraulic shock absorber of embodiment.

(First Embodiment) (FIGS. 1 and 2) The basic configuration of the hydraulic shock absorber 10 is the same as that of the hydraulic shock absorber described in JP-A-2000-18306 (the oil lock collar is omitted). As shown in FIGS. 1 and 2, an inner tube 12 attached to the wheel side is slidably fitted to an outer tube 11 connected to the vehicle body side, and the single-tube type damper 13 is installed upside down. I have.

The damper 13 raises a damper cylinder 14 inside the outer tube 11, raises a piston rod 15 inside the inner tube 12, inserts the piston rod 15 into the damper cylinder 14, and provides the piston rod 15. Damping force generator 17
Is provided.

The hydraulic shock absorber 10 has an oil reservoir 18 having an upper portion as a gas chamber (not shown) between the outer tube 11 and the inner tube 12 on the outer periphery of the damper cylinder 14.

The hydraulic shock absorber 10 includes a stopper ring 20 engaged with the outer periphery of the damper cylinder 14, a spring receiver 22 supported by a backup ring 21, and the inner tube 1.
A suspension spring 23 along the inner periphery of the inner tube 12 is interposed between the bottom and the bottom of the inner tube 2.

Thus, the hydraulic shock absorber 10 absorbs the impact force that the vehicle receives from the road surface by the resilient force of the suspension spring 23 and the gas spring of the gas confined in the gas chamber above the oil reservoir 18. The hydraulic shock absorber 10 is provided with a damping force generator 17 (extension-side damping force generator) provided on the piston 16 of the damper 13 and a damping force generated by a base valve device (compression-side damping force generator) (not shown). Further, the expansion and contraction vibration of the outer tube 11 and the inner tube 12 due to the absorption of the impact force by the suspension spring 23 and the gas spring is suppressed.

The hydraulic shock absorber 10 supports a rebound spring (not shown) at an opening portion of the damper cylinder 14 where the piston rod 15 is inserted, as a shock absorbing structure at the time of maximum extension, and the piston rod 15 has a piston 16 side. The abutment portion provided in the above can be engaged with the rebound spring.

However, the hydraulic shock absorber 10 is provided with a shock absorbing structure at the time of the most compression utilizing the suspension spring 23 as follows. That is, the hydraulic shock absorber 10 always or at least at the time of the intermediate compression stage to the maximum compression causes the entire suspension spring 23 to be immersed in the oil reservoir 18, and the oil reservoir 18 is connected to the lower oil reservoir 18 A by the spring receiver 22. It is partitioned into an upper oil reservoir 18B. The suspension spring 23 has a pitch pa between wires that is close to each other through a small gap a that can avoid metal contact between wires at the time of maximum compression. In this embodiment, the suspension spring 2
The lower portion of the suspension spring 3 except for the upper end portion is a straight portion 24, and the upper end portion of the suspension spring 23 above the straight portion 24 is a reduced diameter portion 25 that can be bridged over the spring receiver 22 (the entire length of the suspension spring 23 is straightened). The part 24 may be used). The straight portion 24 is expanded and deformed at the time of the maximum compression to make the gap with the inner tube 12 minute. Further, in the present embodiment, the pitch between the wires of the suspension spring 23 is set to the above-mentioned pa at equal intervals over the entire length, but the pitch between the wires of the reduced diameter portion 25 is smaller than the pitch between the wires of the straight portion 24. pa may be used.

During the compression stroke of the hydraulic shock absorber 10, the oil sump 18
Oil flows as follows. (1) As the damper cylinder 14 enters the oil reservoir 18 of the inner tube 12 during the compression stroke, the damper cylinder 1
4 is pushed upward through the annular space between the outer periphery of the damper cylinder 14 and the inner periphery of the suspension spring 23, and the gap between the strands of the suspension spring 23.

(2) In the initial stage of compression, the gap between the strands of the suspension spring 23 is large and a large flow path is formed (FIG. 1).
(A)), no damping resistance occurs.

(3) On the most compression side, the gap between the strands of the suspension spring 23 becomes a small gap a to form a small flow path (FIG. 1).
(B)), a large damping force is generated.

Therefore, according to the present embodiment, the following operations are provided. The gap between the strands of the suspension spring 23 gradually decreases with compression. At the time of maximum compression, the suspension spring 23 comes close to each other with a small gap only to avoid metal contact, and becomes almost in close contact. For this reason, when the oil corresponding to the volume of the damper cylinder 14 that enters the oil reservoir 18 in the inner tube 12 at the time of compression is pushed upward through the flow path between the wires of the suspension spring 23, at the time of the most compression, ,
As described above, the flow path between the wires becomes a slight gap, and the pressure (oil lock load) of the lower oil reservoir 18A is greatly increased to cause an oil lock effect, thereby preventing the hydraulic shock absorber 10 from bottoming out. I do.

The buffer structure at the time of the maximum compression can be simplified simply by changing the pitch between the strands of the suspension spring 23, and the cost can be reduced.

The pitch between the strands of the suspension spring 23 gradually decreases throughout the compression process, so that the oil lock load at the time of the above-described maximum compression can be smoothly changed steplessly, thereby improving the riding comfort. it can.

(Second Embodiment) (FIG. 2) The second embodiment is different from the first embodiment in that
2, an orifice 26 communicating the lower oil reservoir 18A and the upper oil reservoir 18B is provided.

Therefore, by adjusting the hole diameter of the orifice 26, the oil lock characteristic at the time of the most compression in the first embodiment can be easily adjusted.

(Third Embodiment) (FIG. 3) The third embodiment is different from the second embodiment in that
The second orifice 26 is provided with a plate valve 27 for adjusting the flow rate of oil from the lower oil reservoir 18A to the upper oil reservoir 18B. 28 is a valve stopper.

Therefore, by adjusting the plate thickness and the number of the plate valves 27 provided in the orifice 26, the oil lock characteristic at the time of the most compression in the second embodiment can be further adjusted.

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

[0032]

As described above, according to the present invention, it is possible to reduce the cost by simplifying the buffer structure at the time of maximum compression, and to improve the riding comfort by changing the oil lock load at the time of maximum compression steplessly. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a main part of a hydraulic shock absorber according to a first embodiment when the hydraulic shock absorber is fully extended.

FIG. 2 is a schematic diagram showing a main part of the hydraulic shock absorber according to the first embodiment at the time of maximum compression.

FIG. 3 is a schematic diagram illustrating a main part of a hydraulic shock absorber according to a second embodiment.

FIG. 4 is a schematic view showing a main part of a hydraulic shock absorber according to a third embodiment.

[Explanation of symbols]

 Reference Signs List 10 Hydraulic shock absorber 11 Outer tube 12 Inner tube 14 Damper cylinder 15 Piston rod 16 Piston 17 Damping force generator 18 Oil reservoir 18A Lower oil reservoir 18B Upper oil reservoir 22 Spring receiver 23 Suspension spring 26 Orifice 27 Plate valve

Claims (3)

[Claims] An inner tube attached to a wheel side is slidably fitted to an outer tube coupled to a vehicle body, a damper cylinder is erected inside the outer tube, and a piston rod is inserted into the inner tube. Standing up, the piston rod is inserted into the damper cylinder, a damping force generator is provided on a piston provided on the piston rod, and an oil reservoir whose upper portion is a gas chamber between the outer tube and the inner tube on the outer periphery of the damper cylinder. A hydraulic shock absorber in which a suspension spring along the inner periphery of the inner tube is interposed between a spring receiver on the outer periphery of the damper cylinder and the bottom of the inner tube, wherein the suspension spring The pitch between the wires is large enough to be in close proximity to each other with a small gap that can avoid metal contacts. Hydraulic shock absorber characterized by comprising Te. 2. The hydraulic shock absorber according to claim 1, wherein the oil reservoir is partitioned into a lower portion and an upper portion by the spring receiver, and an orifice communicating the lower oil reservoir and the upper oil reservoir is provided in the spring receiver. 3. A valve for adjusting a flow rate of oil from a lower oil reservoir to an upper oil reservoir in the orifice.
2. The hydraulic shock absorber according to 1.