JPH0514024Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a damping force adjustment mechanism for a hydraulic shock absorber for a motorcycle or the like.

(Prior art) As a hydraulic shock absorber for a front fork used in a motorcycle, for example, the
As described in Publication No. 49431, a cylindrical fork pipe is slidably inserted into a completely cylindrical bottom case penetrated in the axial direction, and a cylindrical fork pipe is inserted between the bottom case and the fork pipe in the axial direction. A sealed damping force generation chamber is formed, and a piston that slides on the inner circumferential surface of the bottom case is attached to the outer periphery of the fork pipe, and as the fork pipe moves, the piston moves within the damping force generation chamber and damps. Some devices that generate force are known.

(Problem to be solved by the invention) In the above-mentioned hydraulic shock absorber, since the fork pipe is always inside the bottom case, the volume of the damping force generation chamber inside the bottom case changes as the fork pipe moves. However, if a damping force adjustment mechanism is provided, the mechanism will become complicated.

(Means for Solving the Problems) In order to solve the above problems, the present invention connects a piston rod and a sub-rod coaxially to both sides of a piston that slides on the inner circumferential surface of a cylinder, and connects at least one of these rods. The rod is hollow, and an operating member is provided inside the rod, and this operating member is linked to damping force adjusting means provided in the oil passage of the piston.

(Function) Since the piston rod and sub-rod are coaxially connected on both sides of the piston, the sub-rod is prevented from moving back and forth by the same amount as the piston rod moving back and forth, thereby preventing an oil lock state or a negative pressure state.Moreover, the damping of the oil passage of the piston is prevented. Since the force adjustment means is interlocked with the operating member disposed within the hollow rod, the damping force adjustment mechanism can be incorporated with a simple structure.

(Example) An example of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a half-sectional view of a hydraulic shock absorber according to the present invention, FIG. 2 is an enlarged cross-sectional view of the main parts of the same shock absorber, FIG. 3 is a perspective view of an oil seal holder of the same shock absorber, and FIG.
The figure is a plan sectional view of the main part of the buffer, and FIG. 5 is an enlarged vertical sectional view of the temperature compensation chamber.

In this hydraulic shock absorber, an inner tube 2 is slidably inserted into an outer tube 1 from below. The upper end of a sub-cylinder 4 consisting of an outer sub-cylinder 5 and an inner sub-cylinder 6 is attached to the upper end of the outer tube 1 and hangs down inside the inner tube 2. Among the sub-cylinders 4, the lower end of the outer sub-cylinder 5 The upper end of the cylinder 7 is screwed onto the inner peripheral surface of the cylinder 7 so as to face inside the inner tube 2.

An oil hole 10 is formed at the upper end of the inner tube 2 to communicate the inside and outside, and an axle mounting bracket 11 is screwed onto the outer peripheral surface of the lower end of the inner tube 2. There is an oil lock piece 1 on the inner circumferential surface of the
The lower end of a hollow piston rod 15, which is a piston rod, is screwed into the center of the oil lock piece 12 and fixed with a bottom nut 16, so that it faces inside the cylinder 7.

A rod guide 17 and an oil seal 18 are fitted to the lower end of the cylinder 7 to slide on the outer circumferential surface of the hollow piston rod 15, and an oil lock collar 19 is attached to the outer circumference of the rod guide 17. Further, a spring receiver 21 is provided on the outer peripheral surface of the intermediate portion of the cylinder 7, and a suspension spring 22 is interposed between the lower surface of the spring receiver 21 and the upper end surface of the oil lock piece 12. A return spring 23 is mounted.

A piston support member 25 is attached to the tip of the hollow piston rod 15.
A piston 26 that slides on the inner peripheral surface of the cylinder 7 is fitted onto the outer periphery of the cylinder 5 to define the inside of the cylinder 7 into an oil chamber S1 and an oil chamber S2. A side oil passage 28 is formed, and a compression side valve 29 and an expansion side valve 30 for opening and closing these compression side oil passage 27 and expansion side oil passage 28 are attached. A piece 31 is screwed onto the upper end of the piston support member 25, and a hollow sub-rod 3 having the same diameter as the hollow piston rod 15 is attached to this piece 31.
2 is installed, and a hollow piston rod 15 and a hollow sub-rod 32 are connected coaxially to both sides of the piston 26 to form a double-rod structure.

In this case, the outer tube 1, the inner tube 2, the sub-cylinder 4, the cylinder 7, the hollow piston rod 15, the hollow sub-rod 32, etc. are dimensionally long enough so that the upper end of the sub-rod 32 does not protrude from the upper end of the outer tube 1 in the most compressed state. It is forming.

Further, the piston support member 25 includes a piston 26
A valve pressing member 35 that contacts the back surface of the compression side valve 29 of the piston 26 is fitted on the lower side of the piston 26 so as to be able to move up and down, and a notch 36 is formed in the intermediate portion of the piston support member 25 in the axial direction. This notch 36
A spring seat support member 37 is fitted inside so as to be movable up and down, and a spring seat 38 is engaged with the outer edge of the spring seat support member 37, so that the spring seat 38 and the valve pressing member 35 are engaged with each other.
A compression spring 39 is interposed between the valve pressing member 35 and a damping force adjusting mechanism that adjusts the damping force by changing the preset load of the valve pressing member 35.

A push rod 41 is screwed into the upper end of the hollow piston rod 15 so that it can move forward and backward.
The upper end of this push rod 41 is brought into contact with the lower surface of the seat support member 37. Further, as shown in FIG. 4, the upper end of an operating pipe 42 having a substantially half-moon cross section is fitted into the lower end of the push rod 41, and an adjuster star 43 is fitted into the lower end of this operating pipe 42. Rotating the adjuster star 43 serves as an operating mechanism for moving the push rod 41 forward and backward.

Further, a bypass oil passage 45 is formed in the piston support member 25 to communicate with the oil chamber S2 in the axial direction, and an oil passage 46 is formed in the piece 31 to communicate the bypass oil passage 45 with the oil chamber S1. There is. A needle 47 is screwed into the hollow sub-rod 32 so that it can move forward and backward, and the tip of the needle 47 is made to face the upper end opening of the bypass oil passage 45 of the piston support member 25. This is a damping force adjustment mechanism that adjusts the damping force by changing the

The lower end of an operating pipe 48 similar to the operating pipe 42 shown in FIG. 4 is fitted into the upper end of the needle 47, and an adjuster star 49 is fitted into the upper end of the operating pipe 48. By rotating this adjuster star 49, the needle 4
7 serves as an operating mechanism for moving forward and backward.

The upper end of the outer sub-cylinder 5 of the sub-cylinder 4 is screwed onto the inner peripheral surface of the upper end of the outer tube 1, and a fork bolt 51 is screwed onto the inner peripheral surface of the upper end of this outer sub-cylinder 5. By screwing the upper end of the inner sub-cylinder 6 to the inner peripheral surface, the outer sub-cylinder 5 and the inner sub-cylinder 6
An annular oil chamber 52 is formed between the two.

A temperature compensation chamber 53 is formed between the inner circumferential surface of the upper end of the outer sub-cylinder 5 and the outer circumferential surface of the upper end of the inner sub-cylinder 6. free piston 54
A spring 55 is interposed between the upper surface of the free piston 54 and the lower surface of the fork bolt 51 to bias it downward, and as shown in FIG. A seal 56 is slidably fitted, and this oil seal 56 is biased to the closed state by a spring 57 interposed between it and the free piston 54. Furthermore, a temperature compensation valve is provided at the upper end of the outer sub-cylinder 5. Room 53 and outer tube 1
An oil hole 58 is formed that communicates between the inner peripheral surface and the outer peripheral surface of the outer sub-cylinder 5.

Further, an oil seal holder 61 as shown in FIG. 3 is fitted between the inner circumferential surface of the lower end of the outer sub-cylinder 5 and the outer circumferential surface of the lower end of the inner sub-cylinder 6. Oil grooves 62 are formed symmetrically in the axial direction at two locations, and an oil hole 63 is formed that communicates the oil groove 62 with the oil chamber S1.
1 communicates with the oil chamber S4 from the oil hole 63 and oil groove 62 of the oil seal holder 61 through the annular oil chamber 52 between the outer sub-cylinder 5 and the inner sub-cylinder 6 forming the double-structured sub-cylinder 4. I have to.

Further, an oil seal 65 that slides on the outer circumferential surface of the hollow sub-rod 32 is fitted onto the inner circumferential surface of the oil seal holder 61, and a rod guide 66 that slides on the outer circumferential surface of the hollow sub-rod 32 is fitted above the oil seal 65. I'm wearing it.

Further, a cap 68 is fitted to the upper end of the fork bolt 51 to prevent dust and the like from entering the inner sub-cylinder 6.

The operation of the hydraulic shock absorber configured as above will be explained below.

First, when the hollow piston rod 15 moves upward together with the inner tube 2 in the compression stroke, the piston 26 moves upward in the cylinder 7, and the hydraulic oil in the oil chamber S1 passes through the compression side oil passage 27 of the piston 26 and flows to the compression side. The valve 29 is pushed down against the preset force of the valve pressing member 35 to flow into the oil chamber S2 and generate a damping force, and a part of the hydraulic oil in the oil chamber S1 flows into the oil passage 46 of the piece 31. From needle 47
and the bypass oil passage 45 of the piston support member 25, and flows from the bypass oil passage 45 through the notch 36 into the oil chamber S2.

At this time, the hollow piston rod 15 is connected to the cylinder 7.
At the same time as the hollow sub-rod 32 advances into the cylinder 7, the hollow sub-rod 32 withdraws upwardly from the cylinder 7 by the amount by which the hollow piston rod 15 enters, so that an entry volume compensation chamber for the piston rod 15 becomes unnecessary. In addition, the dimensions of this hydraulic shock absorber are such that each part is formed to a length that allows the sub-rod 32 to be housed in the outer tube 1 in the most compressed state shown in FIG. tube 1
There is no interference with other members above.

Furthermore, when the hollow piston rod 15 moves downward together with the inner tube 2 during the extension stroke, the piston 26 moves downward within the cylinder 7, and the hydraulic oil in the oil chamber S2 passes through the extension side oil passage 28 of the piston 26 to the extension side. The valve 30 is pushed up and flows into the oil chamber S1 to generate a damping force, and a portion of the hydraulic oil in the oil chamber S2 passes from the notch 36 of the piston support member 25 to the bypass oil path 45 to the bypass oil path 45. and the needle 47 and flows into the oil chamber S1 via the oil passage 46 of the piece 31. At this time, the hollow piston rod 15 exits from the cylinder 7, and at the same time the hollow sub-rod 32 moves into the hollow piston rod 1.
Since the oil chamber S1 enters into the cylinder 7 by the amount by which the oil is withdrawn, the oil chamber S1 does not become in a negative pressure state.

By rotating an adjuster star 43 rotatably disposed within a hollow piston rod fixed to the bottom of the inner tube, the operating pipe 42 is rotated and the push rod 41 is moved up and down. As the push rod 41 moves up and down, the spring seat 38 moves up and down via the spring seat support member 37, and the biasing force of the spring 39 against the valve pressing member 35 changes, and the compression side valve 29 is moved by the valve pressing member 35. Since the pressure required to open the compression valve 29 changes by changing the pressing force (preset force) against the compressor, the damping force in the compression stroke can be adjusted.

Further, by rotating an adjuster star 49 rotatably disposed within the upper end of the sub-rod 32, the operation pipe 48 is rotated and the needle 47 is rotated.
moves up and down, and the opening amount between the needle 47 and the bypass oil passage 45 changes, so that the hydraulic oil flowing between the oil chamber S1 and the oil chamber S2 through the oil hole 46, the bypass oil passage 45, and the notch 36 is The flow rate can be varied to adjust the damping force during the compression and extension strokes. Adjustment of the needle 47 is carried out by removing the upper cap 68 and rotating the adjuster star 49 which fits into the upper end of the sub-rod 32 in an odd shape. When the adjuster star is rotated, the operation pipe rotates, and the needle 4 is fitted with a different shape at the lower end.
7 rotates and screws back and forth on the inner circumference of the sub-rod.

Furthermore, due to temperature rise, the hydraulic oil in the cylinder 7 expands and its volume increases, or as the hollow piston rod 15 moves in and out, the hydraulic oil in the oil chamber S3 on the outside of the hollow piston rod flows into the oil seal 1.
8 and the outer circumferential surface of the hollow piston rod 15 and the amount of hydraulic oil in the cylinder 7 increases, the increased hydraulic oil flows through the oil hole 63 of the oil seal holder 61. Groove 6
2, further passes through the annular oil chamber 52 between the outer sub-cylinder 5 and the inner sub-cylinder 6, and flows into the oil chamber S4 on the lower side of the free piston 54, thereby preventing the free piston 54 from being used for a long period of time. Gradually push it up.

As the free piston 54 is gradually pushed up, the restoring force of the spring 55 also gradually increases, and the pressure in the S4 chamber also increases. When the pressure in the S4 chamber exceeds the restoring force of the spring 57, the oil seal 56 separates from the free piston 54 and opens, so the hydraulic oil in the space S4 flows into the temperature compensation chamber 53.
further from the temperature compensation chamber 53 to the oil hole 58, the outer tube 1 and the outer sub cylinder 5.
Since the oil returns to the oil chamber S3 through the gap between the cylinder 7 and the cylinder 7, the internal pressure of the cylinder 7 is reduced and a significant change in friction is prevented.

In the above-mentioned embodiment, an example in which the present invention was applied to an inverted type hydraulic shock absorber was described, but it can be similarly applied to an upright type hydraulic shock absorber.

(Effects of the invention) As explained above, according to the invention, the piston rod and the sub-rod are connected coaxially to both sides of the piston that slides on the inner circumferential surface of the cylinder, so the sub-rod moves back and forth by the amount of movement of the piston rod, thereby locking the oil lock. As a result of arranging the operating member of the damping force adjusting means within the hollow rod, the construction is simplified and different adjustments can be made using both rods.

[Brief explanation of the drawing]

Figure 1 is a half-sectional view of the hydraulic shock absorber according to the present invention, Figure 2 is an enlarged cross-sectional view of the main parts of the same shock absorber, Figure 5 is an enlarged longitudinal cross-sectional view of the temperature compensation chamber, and Figure 3 is the same shock absorber. FIG. 4 is a perspective view of the oil seal holder of FIG. In the drawings, 1 is an outer tube, 2 is an inner tube, 4 is a sub cylinder, 5 is an outer sub cylinder, 6 is an inner sub cylinder, 7 is a cylinder, 1
5 is a hollow piston rod, 25 is a piston rod support member, 31 is a piece, 26 is a piston, 27
28 is the compression side oil passage, 29 is the compression side valve, 30 is the expansion side valve, 32 is the subrod, 35 is the valve pressing member, 37 is the seat support member, 38 is the spring seat, and 39 is the spring. , 41 is a push rod, 42 and 48 are operating pipes, 43 and 49 are adjusters, 45 is a bypass oil passage, 46 is an oil hole, and 47 is a needle.

Claims (1)

[Claims for Utility Model Registration] (1) A cylinder is attached to one tube in a pair of tubes that are slidably fitted together, and a piston rod that slides inside the cylinder via a piston is attached to the other tube. A hydraulic shock absorber having a damper interposed therein, wherein the piston has a sub-rod having the same diameter as the piston rod extending concentrically on the opposite side of the piston rod,
At least one of the piston rod or the sub-rod is formed hollow, and an operating member is provided in the hollow portion, and the piston is provided with an oil passage that communicates upper and lower oil chambers to generate a damping force, and this oil passage is A damping force adjustment mechanism for a hydraulic shock absorber, characterized in that the damping force adjustment means is provided to enable adjustment of the damping force, and the damping force adjustment means is linked to the operation member. (2) The damping force adjustment means provided in the oil passage consists of a valve that produces a damping effect depending on the direction of oil flow in the oil passage and a spring mechanism that makes it possible to adjust the preset load of this valve. 2. The damping force adjustment mechanism for a hydraulic shock absorber according to claim 1, comprising a needle valve mechanism that allows adjustment of the opening area of the orifice formed by the passage.