JPH0523864Y2 - - Google Patents

Description

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

(Prior Art) Conventionally, as a damping force adjustment mechanism of a hydraulic shock absorber used in a motorcycle, etc., for example, a needle is placed so as to freely move forward and backward in a bypass oil passage that bypasses a piston part, and this needle is moved forward and backward. ,
There is one in which the damping force generated is adjusted by changing the opening amount of the bypass oil passage.

However, in such a damping force adjustment mechanism, by moving the needle back and forth, the opening amount of the bypass oil passage changes by the same amount in both the compression stroke and the extension stroke, which increases the damping force on the compression side. The adjustment range and the adjustment range of the rebound damping force cannot be set separately.

Therefore, it is conceivable to provide a compression-side needle and an extension-side needle that can move back and forth independently of each other to adjust the compression-side damping force and the extension-side damping force separately.

(Problem to be solved by the invention) However, in the damping force adjustment mechanism that adjusts the damping force by moving the needle back and forth to change the opening amount of the oil passage, the hydraulic oil decreases as the temperature rises. Since the viscosity of the oil decreases, the damping force generated decreases even if the opening amount of the oil passage remains the same.

(Means for Solving the Problems) In order to solve the above problems, the present invention has a first needle having a center hole and a second needle inserted through the center hole, which are slid into a hollow piston rod. In a damping force adjustment mechanism for a hydraulic shock absorber, the damping force adjustment mechanism for a hydraulic shock absorber is configured to separately adjust the damping force corresponding to each expansion/contraction operation of the shock absorber through a forward/backward movement operation unit that advances and retreats each needle. A hollow sub-adjuster pipe is provided between the first needle and its advancing/retracting operation section, which faces the base end of the first needle and defines a first temperature compensation chamber having a volume according to the temperature. The piston rod is slidably interposed between the piston rod and the second needle, and the base end of the second needle is disposed within the sub-adjuster pipe between the second needle and its advancing/retracting operation section. A sub-push rod was slidably interposed to define a second temperature-compensating chamber facing the chamber and having a volume corresponding to the temperature.

(Function) The freely slidable sub-adjuster pipe or sub-push rod moves both needles forward and backward separately by the operation of the respective advance/retreat operation parts, and the sub-adjuster pipe or sub-push rod allows the needles to move forward and backward separately. The temperature compensation chambers formed separately move the needles forward and backward individually depending on the temperature of the hydraulic oil.

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

Fig. 1 is a sectional view of a hydraulic shock absorber equipped with a damping force adjustment mechanism according to the present invention, Fig. 2 is an enlarged sectional view of the main part showing the operating state of the compression stroke of the adjustment mechanism, and Fig. 3 is the same adjustment mechanism. FIG. 2 is an enlarged cross-sectional view of a main part showing the operating state of the extension stroke.

A hollow rod 2 is inserted into the cylinder 1 from below, and a hollow stud 3, which is a piston mounting member, is attached to the tip of the hollow rod 2, and a piston that slides on the inner peripheral surface of the cylinder 1 is attached to the stud 3. 4 is installed to define the inside of the cylinder 1 into an upper oil chamber S1 and a lower oil chamber S2. The piston 4 is formed with a compression side oil passage 5 and a growth side oil passage 6, a compression side valve 7 for opening and closing the compression side oil passage 5 is installed on the lower surface of the piston 4, and a compression side oil passage 5 is formed on the upper surface of the piston 3. An extension valve 8 is installed to open and close the passage 6.

Further, a cylinder cap 10 is fitted onto the inner circumferential surface of the lower end of the cylinder 1.
A rod guide 11 that slides on the outer circumferential surface of the hollow rod 2 is fitted on the upper side of the rod guide 11, and an oil seal 12 that slides on the outer circumferential surface of the hollow rod 2 is fitted on the upper inner circumferential surface of the rod guide 11.
A rebound sheet 13 is fitted on the upper side, and a rebound rubber 14 is fitted on the upper surface of this rebound sheet 13.

Furthermore, an attenuation bracket 16 for attaching to the vehicle body is fitted to the upper end of the cylinder 1, and a sub-tank 17 that communicates with the oil chamber in the cylinder 1 is attached to the side of the upper end. The upper spring seat 18 is screwed on. and,
A lower bracket 21 for attachment to a wheel is attached to the lower end of the hollow rod 2, a retainer 22 is attached to the upper surface of the lower bracket 21, and a stopper rubber sheet 23 is fitted onto the retainer 22. A stopper bar 24 is fitted in the stopper rubber sheet 23, and an underspring sheet 25 is fitted on the upper side of the peripheral edge of the stopper rubber sheet 23, so that the underspring seat 25 and the upper spring seat 18 are connected to each other. A suspension spring 26 is interposed between them.

The damping force adjustment mechanism is constructed as follows. First, the oil hole 31 of the piston 4 and the stud 3 are connected to the stud 3 and the piston 4 as a compression side bypass oil path which bypasses the compression side valve 7 from the compression side oil path 5 of the piston 4 and faces into the lower oil chamber S2.
The oil hole 32 of the stud 3, the oil hole 33 which is a hollow part in the stud 3, and the oil holes 34 and 35 of the stud 3 are formed,
There is an opening between the oil hole 34 and the oil hole 35 during the compression stroke.
A check valve 36 is provided which closes during the extension stroke.

In addition, an oil hole 37 of the piston 4, an oil hole 37 of the piston 4, and an oil hole 37 of the piston 4 are provided as an extension-side bypass oil passage that bypasses the extension-side valve 8 from the extension-side oil passage 6 of the piston 4 and faces into the upper oil chamber S1. Oil hole 38, oil hole 3 which is a hollow part inside stud 3
A valve collar 40 is fitted to the upper end of the hollow part of the stud 3, and the valve collar 40 has an axial oil hole 4 forming a part of the extension side bypass oil passage.
1 and an oil hole 42 in a direction perpendicular to the axial direction, and furthermore, a check valve 43 is interposed on the lower end side of the valve collar 40, which opens the oil hole 39 of the stud 3 in the extension stroke and closes it in the compression stroke. There is.

A first needle 4 inserted into the hollow rod 2 so as to be freely retractable is inserted into the valve seat portion 44 of the oil hole 33 in the stud 3, which forms a part of the compression side bypass oil passage.
A second needle 47, which is inserted into the first needle 45 so as to be freely retractable, faces the valve seat portion 46 of the oil hole 39 in the stud 3, which forms a part of the extension side bypass oil passage.

A sub-adjuster pipe 50 is fitted into the hollow rod 2 on the rear side of the first needle 45 so as to be able to move forward and backward.
This sub-adjuster pipe 50 has a small diameter section 51 at its front end and a temperature compensation chamber 52 between it and the inner peripheral surface of the hollow rod 2.
5 faces the temperature compensation chamber 52, hydraulic oil with a high coefficient of thermal expansion is sealed in the temperature compensation chamber 52, and furthermore, inside the hollow rod 2, the lower side of the sub-adjuster pipe 50 can be moved forward and backward. An adjuster pipe 53 forming a part is inserted through it so that it can move forward and backward.

A sub push rod 54 is fitted into the sub adjuster pipe 50 on the rear side of the second needle 47 so as to be able to move forward and backward.
By forming the temperature compensation chamber 56 between the inner circumferential surface and the temperature compensation chamber 5, the rear part of the second needle 47 is connected to the temperature compensation chamber 5.
6, a hydraulic oil with a high coefficient of thermal expansion is sealed in the temperature compensation chamber 56, and a push rod 57, which serves as an advancing/retracting operation section below the sub push rod 54, is placed in the adjuster pipe 53. It can be inserted freely.

Further, a forked portion 61 is formed at the lower end of the adjuster pipe 53, and the lower end of this forked portion 61 forms a tapered surface to form a tapered surface formed on the upper surface of the first slider 62. The lower end of the push rod 57 is brought into contact with a tapered surface formed on the upper surface of a second slider 63 fitted within the forked portion 61 of the adjuster pipe 53.

The second slider 63 is slidably fitted into the space formed on the upper surface of the first slider 62, and the first slider 62 is slidably fitted into the lower bracket 21. The first slider 62 and the second slider 63 are slidably fitted into each other, and a groove is formed on the lower surface of the first slider 61, and the tip of the key 65 is fitted into the groove. This prevents the first slider 62 from rotating.

Further, a first adjuster 67 is provided in the adjuster holding member 66 fitted to the lower bracket 21.
are rotatably fitted, and this first adjuster star 6
The first slider 62 is screwed into the threaded portion 68 formed at the tip of the lower bracket 21, and the second adjuster 71 is rotatably fitted into the adjuster holding member 70 fitted into the lower bracket 21. Threaded portion 72 formed at the tip of the second adjuster star 71
By screwing the second slider 63 together and rotating the first adjuster 67, the first slider 62 moves back and forth, the adjuster pipe 53 moves up and down, and the first needle 45 moves back and forth. By rotating the second adjuster 71, the second slider 63 moves forward and backward, the push rod 57 moves up and down, and the second needle 47 moves forward and backward.

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

First, as the hollow rod 2 moves upward together with the piston 4 during the compression stroke, the hydraulic oil in the upper oil chamber S1 passes through the compression side oil passage 5 of the piston 4, opens the compression side valve 7, and flows into the lower oil chamber S2. It flows into the inside and generates a damping force.

At this time, a part of the hydraulic oil flowing into the compression side oil passage 5 from the upper oil chamber S1 flows into the oil hole 31 of the piston 4, the oil hole 32 of the stud 3, and the oil hole 32 of the stud 3, as shown by the arrow in FIG. Oil hole 3 which is part of the hollow part inside
3, the valve seat 44 and the first needle 4
The oil enters the oil hole 34 of the stud 3 through the gap between the stud 3, the check valve 36 is opened, and the oil flows into the lower oil chamber S2 from the oil hole 35 of the stud 3, bypassing the compression side valve 7. Further, in this case, the check valve 43 closes the oil hole 39 of the stud 3 by the hydraulic oil flowing into the oil hole 41 of the valve collar 40 from the upper oil chamber S1.

Therefore, by advancing and retracting the adjuster pipe 53 and advancing and retracting the first needle 45 via the sub-adjuster pipe 50, the first needle 4
Width of the gap between 5 and the valve seat portion 44 (opening amount)
By changing , the compression damping force generated can be adjusted. This adjuster pipe 5
3 is moved forward and backward by the first adjuster 6 as mentioned above.
This can be done by rotating 7.

In this case, as the temperature of the hydraulic oil in the shock absorber increases, the viscosity decreases and the damping force generated by the piston 4 decreases, but due to the temperature increase, the hydraulic oil in the temperature compensation chamber 52 thermally expands. Since the volume increases, the first needle 45 enters and the opening amount between the valve seat portion 44 becomes smaller, the flow velocity increases, and a decrease in damping force is suppressed. Since only the front side of the temperature compensation chamber 52 is opened, the entire amount of oil due to sufficient thermal expansion can act on the first needle 45 as a displacement in the axial direction.

Further, as the hollow rod 2 moves downward together with the piston 4 during the extension stroke, the hydraulic oil in the lower oil chamber S2 passes through the extension side oil passage 6 of the piston 4 and opens the extension side valve 8, causing the upper oil chamber S1 to open. It flows into the inside and generates a damping force.

At this time, a part of the hydraulic oil that has flowed into the extension side oil passage 6 from the lower oil chamber S2 is transferred from the oil hole 37 of the piston 4 to the second needle 4 as shown by the arrow in FIG.
The oil flows into the oil hole 39 in the stud 3 through the gap between the oil hole 7 and the valve seat 46, opens the check valve 43, bypasses the extension valve 8 through the oil hole 42 and the oil hole 41 in the valve collar 40, and flows into the upper part. It flows into the oil chamber S1. In this case, the lower oil chamber S
The check valve 36 closes the oil hole 34 of the stud 3 by the hydraulic oil flowing into the oil hole 35 of the stud 3 from the valve 2.

Therefore, the push rod 57 is moved back and forth to move the second needle 4 through the sub push rod 54.
7 moves back and forth to change the width (opening amount) of the gap between the second needle 47 and the valve seat portion 46, the generated extension-side damping force can be adjusted. The push rod 57 can be moved back and forth by rotating the second adjuster 71 as described above.

In this case, as the temperature of the hydraulic oil in the shock absorber increases, the viscosity decreases and the damping force generated by the piston 4 decreases, but due to the temperature rise, the hydraulic oil in the temperature compensation chamber 56 thermally expands. Since the volume increases, the second needle 47 enters and the opening amount between the second needle 47 and the valve seat portion 46 becomes smaller, the bypass amount is attenuated, and a decrease in the damping force is suppressed. Since only the front side of the temperature compensation chamber 56 is opened, a sufficient amount of expansion in the axial direction can be obtained.

In this way, by moving the first needle 45 and the second needle 47 back and forth independently of each other, the compression damping force and the extension damping force can be adjusted by different amounts, and moreover, it is possible to adjust the compression damping force and the extension damping force by different amounts. It is possible to suppress damping force fluctuations caused by Further, as in this embodiment, the check valve for opening and closing the compression side bypass oil passage and the extension side bypass oil passage is provided at a position close to the outer surface of the stud 3, thereby facilitating processing.

(Effects of the invention) As explained above, according to the invention, the slidable sub-adjuster pipe or sub-push rod moves both needles individually forward and backward by the operation of each advance/retreat operation section, and Temperature compensation chambers formed separately by the sub-adjuster pipe or the sub-push rod move the needles individually in accordance with the temperature of the hydraulic oil.

Therefore, by making the movement characteristics of the needle in the temperature compensation chamber correspond to the viscosity change due to the temperature of the hydraulic oil for generating damping force, it is possible to have stable damping characteristics without being affected by the temperature of the hydraulic oil, and to have a structure that is stable. A simple buffer can be obtained.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a hydraulic shock absorber equipped with a damping force adjustment mechanism according to the present invention, Fig. 2 is an enlarged sectional view of the main part showing the operating state of the compression stroke of the adjustment mechanism, and Fig. 3 is the same adjustment mechanism. FIG. 2 is an enlarged cross-sectional view of a main part showing the operating state of the extension stroke. In addition, in the drawing, 1 is a cylinder, 2 is a hollow rod,
4 is a piston, 5 is a compression side oil passage, 6 is an extension side oil passage, 7 is a compression side valve, 8 is an extension side valve, 3
6 and 43 are check valves, 45 is a first needle, 47 is a second needle, 50 is a sub-adjuster pipe, 52 and 56 are temperature compensation chambers, 53 is an adjuster pipe (advance/retract operation part), and 54 is a sub-shuttle valve. 57 is a push rod (advance/retract operation section).

Claims (1)

[Scope of utility model registration request] A first needle having a center hole and a second needle inserted through the center hole are slidably provided in a hollow piston rod, and buffering is provided through an advance/retreat operation section that moves each needle forward and backward. In a damping force adjustment mechanism for a hydraulic shock absorber that individually adjusts the damping force corresponding to each expansion and contraction movement of the device,
A hollow space is provided between the first needle of the damping force adjustment mechanism and its advancement/retraction operation section, and defines a first temperature compensation chamber facing the base end of the first needle and having a volume depending on the temperature. A sub-adjuster pipe is slidably interposed between the piston rod and the second needle, and a sub-adjuster pipe is provided in the sub-adjuster pipe between the second needle and its advancing/retracting operation section. Damping force of a hydraulic shock absorber characterized in that a sub-push rod is slidably interposed to define a second temperature compensation chamber facing the base end of the second needle and having a volume corresponding to the temperature. Adjustment mechanism.