JPH11287279A - Damping force adjusting device of hydraulic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust the retractable amount of an adjusting rod so as to make the fine adjustment of a throttling degree of the opening area of its bypass passage at the side of a maximum throttling region, in this damping force adjusting device which makes the adjusting rod installed with a needle valve at the tip, retractable before and behind, thereby adjusting the opening are of the bypass passage where the needle valve is facing. SOLUTION: In this damping force adjusting device of a hydraulic shock absorber, a taper surface 49B of a slider 49 is made up into a curved form where an amount of travel of a needle valve 43 to a unit proceeding amount of the slider 49 is decreased in proportion as the needle valve 43 throttles its opening area after approaching and traveling toward a bypass passage 44.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping force adjusting device for a hydraulic shock absorber interposed between a vehicle body such as a motorcycle and wheels for absorbing a shock from a road surface.

[0002]

2. Description of the Related Art Conventionally, as a damping force adjusting device for a hydraulic shock absorber, an oil chamber is defined in the shock absorber by a partition member supported by a hollow rod inserted into the shock absorber, and an oil chamber on both sides of the partition member is formed in the hollow rod. Forming a bypass channel that allows communication between the chambers,
An adjusting rod is provided vertically freely in the hollow rod in the hollow rod,
A needle valve for adjusting the opening area of the bypass flow path is provided at the distal end of the adjusting rod, and the taper surface of the slider that advances and retreats in a direction intersecting with the axial direction of the adjusting rod is brought into contact with the base end of the adjusting rod, and the adjusting rod is moved. There is one in which the opening area of the bypass flow path is adjusted by moving the needle valve by moving the needle valve in the axial direction.

In this prior art, when a hydraulic shock absorber is compressed or expanded, oil flowing through a bypass flow path narrowed by a needle valve generates a compression side damping force or a compression side damping force. The damping force can suppress the expansion and contraction vibration of the hydraulic shock absorber.

[0004]

However, in the prior art, the tapered surface of the slider is linear, and the amount of movement of the needle valve with respect to the unit of advance of the slider is always constant. For this reason, if the tapered surface of the conical valve body of the needle valve forms a continuous straight line of one stage, the needle valve is moved by the advance and retreat of the slider on the maximum throttle region side where the needle valve approaches the bypass flow path. It is not possible to finely adjust the degree of contraction of the opening area by the needle valve, and thus to finely adjust the damping force.

In order to make it possible to finely adjust the degree of restriction of the opening area of the bypass passage by the needle valve on the side of the maximum restriction region while making the taper surface of the slider straight, the taper of the conical valve element of the needle valve is set. When the surface has a two-step polygonal line shape (a taper angle on the maximum throttle side is made small), it is difficult to machine the tapered surface of the needle valve, and oil flowing through the bypass flow passage has two stages of the needle valve. There is a risk of being disturbed around the tapered surface, and the damping force cannot be adjusted smoothly.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a damping force adjusting device for adjusting an opening area of a bypass passage facing a needle valve by moving an adjusting rod provided with a needle valve at a distal end in an axial direction. An object of the present invention is to adjust the amount of advance and retreat of the adjustment rod so as to finely adjust the degree of restriction of the opening area of the bypass flow path.

[0007]

According to the first aspect of the present invention, an oil chamber is defined in a shock absorber by a partition member supported by a hollow rod inserted in the shock absorber, and the hollow rod is provided on both sides of the partition member. To form a bypass passage that allows the oil chambers to communicate with each other,
An adjusting rod is provided vertically freely in the hollow rod in the hollow rod,
A needle valve for adjusting the opening area of the bypass flow path is provided at the distal end of the adjusting rod, and the taper surface of the slider that advances and retreats in a direction intersecting with the axial direction of the adjusting rod is brought into contact with the base end of the adjusting rod, and the adjusting rod is moved. In the damping force adjusting device for a hydraulic shock absorber in which the opening area of the bypass passage is adjusted by moving the needle valve by moving the needle valve axially, the needle valve moves closer to the bypass passage on the tapered surface of the slider. Then, as the opening area is reduced, the amount of movement of the needle valve with respect to the unit advance amount of the slider is formed in a curved shape.

According to a second aspect of the present invention, in the first aspect of the present invention, the taper surface of the needle valve provided at the distal end of the adjusting rod is formed as a continuous straight line of one stage. Things.

[0009]

According to the first aspect of the present invention, the following operations are provided. As the needle valve moves closer to the bypass flow path on the tapered surface of the slider to reduce the opening area,
The curve shape is such that the amount of movement of the needle valve with respect to the unit advance amount of the slider decreases. Therefore, on the maximum throttle side where the needle valve approaches the bypass flow path, the degree of throttle of the opening area by the needle valve moved by the advance and retreat of the slider can be finely adjusted, and the damping force can be finely adjusted.

According to the second aspect of the present invention, the following operations are provided. Since the tapered surface of the valve body of the needle valve is formed in a one-step linear shape, the tapered surface of the needle valve can be easily processed. Further, there is no possibility that the oil flowing through the bypass flow path is disturbed around the tapered surface of the needle valve, and the damping force can be adjusted smoothly.

[0011]

FIG. 1 is a schematic view showing a hydraulic shock absorber,
2 is a lower enlarged view of the hydraulic shock absorber, FIG. 3 is an upper enlarged view of the hydraulic shock absorber, FIG. 4 is a schematic view showing the slider device, FIG. 5 is a schematic view showing an adjustment rod with a needle valve, and FIG. 6 is a base valve. It is a schematic diagram which shows an apparatus.

The hydraulic shock absorber 10 has a hollow piston rod 12 inserted into a cylinder 11 as shown in FIGS.
A suspension spring 13 is provided outside the cylinder 11 and the piston rod 12.

The cylinder 11 has a vehicle body-side mounting portion 14,
The piston rod 12 includes a wheel-side mounting portion 15. A spring support adjusting ring 16 and a spring support 17 are screwed around the outer periphery of the cylinder 11, and the spring support 1 is mounted on the piston rod 12.
8 is fixed, a suspension spring 13 is interposed between the spring support 17 and the spring support 18, and the spring support adjustment ring 1
The set length of the suspension spring 13 can be adjusted by the screwing of the spring support 6 and the spring receiver 17. The elastic force of the suspension spring 13 absorbs the impact force that the vehicle receives from the road surface.

The cylinder 11 has a rod guide 21 through which the piston rod 12 passes. The rod guide 21
The piston rod 12 is mounted on the cylinder 11 via an O-ring 22 in a liquid-tight manner, and the piston rod 12 is slidable in a liquid-tight manner on an inner diameter portion provided with an oil seal 23, a bush 24, and a dust seal 25. The cylinder 11 is provided with a compression side bumper 26 outside the rod guide 21, and at the time of maximum compression, the compression side bumper 26 abuts against a bumper stopper 27 provided in the piston rod 12 so that the maximum compression stroke can be regulated. Further, the cylinder 11 includes an extension-side bump rubber 28 inside the rod guide 21.

The hydraulic shock absorber 10 has a piston valve device (extension-side damping force generator) 30 and a base valve device (compression-side damping force generator) 60. Hydraulic shock absorber 1
0 is the piston valve device 30 and the base valve device 60
The expansion and contraction vibration of the cylinder 11 and the piston rod 12 due to the absorption of the impact force by the suspension spring 13 is suppressed by the damping force generated.

(Piston Valve Apparatus 30) (FIGS. 1 to 5) The piston valve apparatus 30 includes a valve stopper 31, a pressure side valve 32, a piston 33, and an extension side valve 34 at the end of a piston rod 12 inserted into the cylinder 11. , And a valve stopper 35, which is fixed with a nut 36.

The piston 33 slidably contacts the inside of the cylinder 11 in a liquid-tight manner via an O-ring 37A and a piston ring 37B provided on the outer peripheral portion, and the inside of the cylinder 11 communicates with a piston-side oil chamber 38A in which the piston rod 12 is not accommodated. , And a rod-side oil chamber 38B in which the piston rod 12 is housed. The piston 33 includes a compression-side valve 32 and a compression-side flow path 39 that enables communication between the piston-side oil chamber 38A and the rod-side oil chamber 38B. The piston 33 includes an extension-side valve 34 and includes a piston-side oil chamber 38A and a rod-side oil chamber. 38B. The distance Ra from the support center of the compression side valve 32 (same as the center of the piston 33) to the center of the compression side flow path 39, and the distance from the support center of the expansion side valve 34 (same as the center of the piston 33) to the expansion side flow path 40 Is set to Ra> Rb, and the extension damping force based on the bending deformation of the expansion valve 34 is larger than the compression damping force based on the bending deformation of the compression valve 32. It is set as follows.

In the piston valve device 30, the damping force adjusting rod 42 operated by the slider device 41 is passed through the hollow portion of the piston rod 12 so as to be able to advance and retreat, and the piston valve is controlled by the needle valve 43 at the tip of the adjusting rod 42. The opening area of the bypass passage 44 between the piston-side oil chamber 38A and the rod-side oil chamber 38B provided in the piston 12 is adjustable.

As shown in FIG. 4, the slider device 41 includes an adjust holder 45 press-fitted and fixed to the wheel-side mounting portion 15 of the piston rod 12 in a direction perpendicular to the axial direction of the piston rod 12, and the adjust holder 45 A pivotally mounted adjuster 46, a ball 48 urged by a set spring 47 in a direction outwardly perpendicular to the axis of the adjuster 46 to be engageable with an engagement recess 45 </ b> A of the adjust holder 45, and a screw portion of the adjuster 46. And a slider 40 which is screwed into the slider. The adjuster 46 has an operation groove 46A.
The operation end side provided with is supported by the adjust holder 45,
The non-operation end side is supported by the wheel side mounting portion 15 and the operation groove 46
The ball 48 is rotated by a tool engaged with A, and the balls 48 are arranged at a plurality of positions in the circumferential direction of the adjust holder 45 (evenly distributed).
The engagement recesses 45A are sequentially engaged with each other, and the adjuster 46 can be set to the rotation stop position of the adjusters 46 with a sense of moderation. On the other hand, when the slider 49 is screwed to the screw portion of the adjuster 46, the distal end guide portion of the guide bolt 50 provided on the wheel side mounting portion 15 is engaged with the guide groove 49 </ b> A provided in the axial direction of the slider 49. Has been entered. Thus, the slider device 41 enables the slider 49 to advance and retreat in a direction orthogonal to the axial direction of the adjustment rod 42 by rotating the adjuster 46.

As shown in FIG. 5, the adjusting rod 42 is inserted into the hollow portion of the piston rod 12 in a liquid-tight manner via an O-ring 51, and the needle valve 43 at the end of the adjusting valve 42 is used for the bypass flow path 4.
Adjust the opening area of 4. At this time, the adjustment rod 42
The ball 52, which is rotatably held at its base end by caulking, is pressed against the tapered surface 49 </ b> B of the slider 49 by a thrust force based on the oil pressure of the piston side oil chamber 38 </ b> A of the cylinder 11.

That is, in the piston valve device 30, the taper surface 49B of the slider 49 is
The slider 49 is brought into contact with the ball 52 at the base end of the slider 49 based on a rotation operation applied to the adjuster 46 of the slider device 41.
The adjustment rod 42 is advanced and retracted in the axial direction by the advance and retreat, and the opening area of the bypass flow path 44 is adjusted by moving the needle valve 43 at the tip of the adjustment rod 42. In addition, the needle valve 43
The shape of the valve body and the shape of the tapered surface 49B of the slider 49 will be described later in detail.

Therefore, when the hydraulic shock absorber 10 is compressed, the oil in the piston side oil chamber 38A passes through the pressure side flow path 39, opens the pressure side valve 32, and is guided to the rod side oil chamber 38B.

Also, when the hydraulic shock absorber 10 is extended, when the relative speed between the cylinder 11 and the piston rod 12 is low, the oil in the rod-side oil chamber 38B passes through the bypass passage 44 having the needle valve 43 and the piston-side oil. It flows into the chamber 38, and the expansion side damping force is generated by the throttle resistance of the needle valve 43 during this time. This damping force is adjusted by rotating the adjuster 46 of the slider device 41.

When the relative speed between the cylinder 11 and the piston rod 12 is medium or high when the hydraulic shock absorber 10 is extended, the oil in the rod-side oil chamber 38B passes through the extension-side flow path 40 and deflects the extension-side valve 34. It is deformed and guided to the piston-side oil chamber 38A, and generates an extension-side damping force.

(Base valve device 60) (FIGS. 1 to 3,
FIG. 6) The base valve device 60 is provided with a reservoir 61 in the cylinder 11.
And the inside sealed by the cap 62 of the reservoir 61 is a diaphragm type (a free piston type is also possible).
Partitioning into an oil chamber 64A and a gas chamber 64B. The cap 62 is provided with a gas sealing valve 65 for sealing a pressurized gas into the gas chamber 64B.

As shown in FIG. 6, the base valve device 60 is provided with a valve housing 71 in a communication area between the piston side oil chamber 38A of the cylinder 11 and the oil chamber 64A of the reservoir 61, and is screwed to the cylinder 11. The valve housing 71 is fixed by a plug bolt 72 that is provided. A piston 73 is fixed to the valve housing 71, and the piston 73 is provided with a flow path 74. A bypass forming bolt 75 is provided at the center of the piston 73 with a nut 76.
A pressure side valve 77 that opens around the center of the bypass forming bolt 75 when the flow path 74 is compressed, and an expansion side valve (check valve) that conducts when the flow path 74 is extended.
78 and a valve spring 79 for supporting the extension side valve 78 on the rear surface are provided. Reference numeral 80 denotes a valve seat. Further, a valve receiver 82 that is urged by a spring 81 and applies an initial load to the pressure-side valve 77 is attached to the bypass forming bolt 75.

In the base valve device 60, an adjusting lever 83 is fitted to the plug bolt 72 so as to be rotatable in a liquid-tight manner, and an adjusting guide 84 is screwed to a screw portion of the adjusting lever 83. Parallel pin 8 slidably engaged in a guide groove provided in the direction
The adjustment guide 84 is connected to the adjustment guide 5, and the adjustment guide 84 supports the above-described initial load setting spring 81 for the compression-side valve 77 via the spring seat 86 on the back side. Therefore, by rotating the adjustment lever 83, the adjustment guide 84 is moved in the axial direction, and as a result, the initial set length of the spring 81 of the pressure side valve 77, in other words, the initial load can be adjusted.

In the base valve device 60, an adjustment rod 87 is rotatably mounted on an adjustment lever 83, and a needle valve 88 which is rotatably engaged with the distal end of the adjustment rod 87 and is relatively movable in the axial direction. , And an outer thread portion of the needle valve 88 is screwed to a nut 89 which is caulked and fixed to the distal end side of the adjustment lever 83. The adjusting rod 87 is provided with a ball 91 that is urged by a set spring 90 outward in the axial direction of the adjusting rod 87 to be able to engage with the engaging recess 83A of the adjusting lever 83. Thereby, the adjusting rod 87 is rotated by a tool engaged with the operation groove 87A of the adjusting rod 87, and the balls 91 are arranged (equally arranged) at a plurality of positions in the circumferential direction of the adjusting lever 83 in the engaging recess 83A. The needle valve 88 is engaged with each of them in order, and the adjusting rod 87 is set to one of their rotational operation positions, so that the needle valve 88 is connected to the bypass forming bolt 7.
5 with respect to the bypass channel 75A, and the opening area of the bypass channel 75A can be adjusted.

Therefore, when the hydraulic shock absorber 10 is compressed, oil corresponding to the volume of the piston rod 12 that has entered the cylinder 11 flows from the piston side oil chamber 38A into the bypass passage 75A of the bypass forming bolt 75 or the flow of the piston 73. The oil is discharged to the oil chamber 64A of the reservoir 61 through the passage 74. At this time, when the relative speed between the cylinder 11 and the piston rod 12 is low, the compression side damping force is obtained by the throttle resistance of the needle valve 88 provided in the bypass flow path 75A. This damping force is adjusted by adjusting the position of the needle valve 88 by the adjusting rod 87. When the relative speed between the cylinder 11 and the piston rod 12 is medium to high, the oil passing through the flow path 74 from the piston-side oil chamber 38A bends and deforms the pressure-side valve 77 so that the oil chamber 6 of the reservoir 61 is deformed.
4A to generate a compression-side damping force. This damping force is
The initial load of the spring 81 for the compression side valve 77 is adjusted by adjusting the adjustment lever 83.

When the hydraulic shock absorber 10 is extended, the cylinder 1
The oil corresponding to the withdrawal volume of the piston rod 12 withdrawing from 1 is transferred from the oil chamber 64A of the reservoir 61 to the piston-side oil chamber 38A through the expansion valve 78 and the flow path 74.

The pressurized gas sealed in the gas chamber 64B of the reservoir 61 pressurizes the hydraulic oil in the cylinder 11, and when compressed, passes from the piston side oil chamber 38A to the oil chamber 64A via the flow path 74 of the piston 73. This prevents the oil from blowing up, thereby preventing the occurrence of cavitation in which air or the like is mixed in the oil, and also prevents the generation of damping force during compression following expansion (spilling).

Accordingly, the hydraulic shock absorber 10 performs a damping action as follows. (Compression) When the hydraulic shock absorber 10 is compressed, (a) in the base valve device 60, the bypass passage 75A of the bypass forming bolt 75 whose opening is adjusted by the needle valve 88,
Alternatively, a pressure-side damping force is generated by oil passing through a pressure-side valve 77 provided in the flow path 74 of the piston 23, and (b)
In the piston valve device 30, a pressure-side damping force is generated by oil passing through the pressure-side valve 32 provided in the pressure-side flow path 39 of the piston 33.

(At the time of extension) When the hydraulic shock absorber 10 is extended,
In the piston valve device 30, the bypass passage 4 of the piston rod 12 whose opening is adjusted by the needle valve 43.
4, or an oil passing through the expansion valve 34 provided in the expansion flow path 40 of the piston 33 generates an expansion damping force.

The vibration of the hydraulic shock absorber 10 is suppressed by the damping force on the compression side and the expansion side.

When the hydraulic shock absorber 10 is fully compressed, the bumper 26 on the side of the cylinder 11 and the bumper stopper 27 on the side of the piston rod 12 perform a buffering operation at the time of maximum compression. When the hydraulic shock absorber 10 is fully extended, the bump rubber 28 on the side of the cylinder 11 and the piston rod 12
By the abutment with the valve stopper 31 on the side of, the cushioning function at the time of extension and extension is achieved.

In the hydraulic shock absorber 10, the damping force adjusting rod 42 is moved forward and backward by the slider 49 of the slider device 41, and the opening area of the bypass passage 44 is adjusted by the needle valve 43 of the adjusting rod 42. Has the following configuration to enable fine adjustment.

That is, in the slider device 41, FIG.
(B), the tapered surface 4 of the slider 49 as shown in FIG.
As the needle valve 43 moves closer to the bypass flow path 44 and narrows the opening area of the needle valve 9B, the amount of advance in the unit of the slider 49 (the amount of rotational operation in the unit of the adjuster 46).
The change rate of the movement amount of the needle valve 43 with respect to (for example, one rotation operation amount in which the ball 48 of the adjuster 46 is engaged and disengaged with the engagement recess 45A equally arranged in the circumferential direction of the adjustment holder 45) gradually decreases. It is formed in a curved shape.

In the present embodiment, the needle valve 43 is moved in the direction of pulling the slider 49 toward the operating portion of the adjuster 46.
Of the slider 49, the tapered surface 49 of the slider 49
B pushes the adjusting rod 42 so that the needle valve 4
The curve of the tapered surface 49B is determined so that the rate of change of the amount of movement of No. 3 decreases in the pulling direction. However, the degree of throttle of the needle valve 43 increases in the direction in which the slider 49 is pushed to the opposite side of the operating portion of the adjuster 46, and the amount of movement of the needle valve 43 due to the curved taper surface 49B of the slider 49 pushing the adjustment rod 42 is changed. The curve of the tapered surface 49B may be determined so that the rate decreases in the pushing progress direction.

At this time, the conical valve body of the needle valve 43 has a one-stage linear tapered surface 4 as shown in FIG.
3A.

Therefore, according to the present embodiment, the following operations are provided. According to the first aspect of the present invention, the slider 4
As the needle valve 43 moves closer to the bypass flow path 44 on the tapered surface 49B of 9 and narrows the opening area thereof, the needle valve 4 with respect to the unit advance amount of the slider 49
3 was made to have a curved shape in which the amount of movement was reduced. Therefore, on the maximum throttle side where the needle valve 43 approaches the bypass flow path 44,
Needle valve 43 moved by moving slider 49 forward and backward
, The fineness of the aperture area can be finely adjusted, and the damping force can be finely adjusted.

According to the second aspect of the present invention, since the tapered surface 49B of the valve body of the needle valve 43 has a single-step linear shape, the tapered surface 49B of the needle valve 43 can be easily processed. Further, the oil flowing through the bypass passage 44 is not likely to be disturbed around the tapered surface 49B of the needle valve 43, and the damping force can be adjusted smoothly.

Therefore, according to the present invention, the damping force given by the needle valve 43 to the unit operation amount of the adjuster 46 can be arbitrarily changed by variously changing the selection of the curve of the curved tapered surface 49 B provided on the slider 49. Can be adjusted.

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 can be changed within the scope of the present invention. The present invention is also included in the present invention. For example, in the present embodiment, the present invention is applied to the damping force adjusting device using the needle valve 43 on the side of the piston valve device 30, but the present invention is applied to a damping force adjusting device using the needle valve 88 on the side of the base valve device 60. Can be widely used in hydraulic shock absorbers.

[0044]

As described above, according to the present invention, there is provided a damping force adjusting device for adjusting an opening area of a bypass passage facing a needle valve by moving an adjusting rod provided with a needle valve at a distal end in an axial direction. The amount of advance / retreat of the adjustment rod can be adjusted so as to finely adjust the degree of throttle of the opening area of the bypass flow path on the maximum throttle area side.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a hydraulic shock absorber.

FIG. 2 is an enlarged view of a lower portion of the hydraulic shock absorber.

FIG. 3 is an enlarged top view of the hydraulic shock absorber.

FIG. 4 is a schematic view showing a slider device.

FIG. 5 is a schematic view showing an adjustment rod with a needle valve.

FIG. 6 is a schematic view showing a base valve device.

[Explanation of symbols]

 Reference Signs List 10 hydraulic shock absorber 12 piston rod (hollow rod) 33 piston (partition member) 38A piston side oil chamber 38B rod side oil chamber 42 damping force adjusting rod 43 needle valve 44 bypass flow path 49 slider 49B tapered surface

Claims (2)

[Claims] An oil chamber is defined in a shock absorber by a partition member supported by a hollow rod inserted into the shock absorber, and a bypass flow passage is formed in the hollow rod so that the oil chambers on both sides of the partition member can communicate with each other. An adjustment rod is provided in the hollow rod so as to be able to advance and retreat in the axial direction. A needle valve for adjusting the opening area of the bypass flow path is provided at the tip of the adjustment rod, and the base end of the adjustment rod intersects the axial direction of the adjustment rod. A damping force adjusting device for a hydraulic shock absorber in which a taper surface of a slider that advances and retreats in the direction abuts and an adjusting rod advances and retreats in an axial direction to adjust an opening area of a bypass flow passage by moving a needle valve; As the needle valve moves closer to the bypass flow path on the tapered surface of the slider and narrows the opening area, the amount of movement of the needle valve with respect to the unit advance amount of the slider decreases in a curved shape Hydraulic shock absorber damping force adjusting apparatus characterized by forming the. 2. The damping force adjustment of a hydraulic shock absorber according to claim 1, wherein a taper surface of a needle valve provided at a tip of the adjustment rod has a continuous linear shape in one stage. apparatus.