JP2001090768A - Damping force adjustable hydraulic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a damping for an adjustable hydraulic shock absorber capable of preventing swelling of a pilot type damping valve with simple constitution and capable of expanding an adjusting range of a damping force characteristic. SOLUTION: This damping force adjustable hydraulic shock absorber is provided with an annular valve member 23 having an outer diameter larger than an outside diametrical dimension of a valve seat 21 for separating/sitting a main disc valve 22, a pressure receiving area difference is formed between both, and a check valve 100 is arranged for energizing the main disc valve 22 in the valve closing direction. Since valve closing directional oil pressure acts on the main disc valve 22 by the pressure receiving area difference at extension stroke time, even if a valve set load of a disc member 26 is set to almost 0, high damping force can be generated at extension side hard time so that an adjusting width of damping force can be expanded by this extent. While, swelling force generated in the main disk valve 22 at backflow (contraction stroke) time is canceled by energizing force of the disc member 26 and the check valve 100 and oil pressure of a cylinder lower chamber 2b acting on the check valve 100 to prevent swelling of the main disc valve 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping force-adjustable hydraulic shock absorber mounted on a suspension system of a vehicle such as an automobile.

[0002]

2. Description of the Related Art A hydraulic shock absorber mounted on a suspension system of a vehicle such as an automobile is provided with a damping force that can be appropriately adjusted in order to improve riding comfort and steering stability in accordance with road surface conditions, running conditions, and the like. There is a damping force adjustable hydraulic shock absorber.

An example of a damping force adjusting type hydraulic shock absorber is disclosed by the present inventors in Japanese Patent Application No. 11-121787. This damping force-adjustable hydraulic shock absorber includes a cylinder filled with an oil liquid, a piston slidably fitted in the cylinder, one end connected to the piston, and the other end extending outside the cylinder. A main passage which is connected to the cylinder, which is connected to the cylinder, and through which the oil flows by sliding the piston; a pilot damping valve (main disc valve) provided in the main passage; A valve member provided on the back surface of the valve to form a pilot chamber; a tubular sliding member slidably fitted to the valve member and in contact with the pilot damping valve; and a part of the main passage. A sub-passage provided in communication with the back of the valve member from the pilot chamber via a pressure control valve so as to bypass the pilot chamber and the pilot-type damping valve are biased through the sliding member in a valve closing direction. A spring and a seat portion on which the pilot-type damping valve is detached and seated, wherein the outer diameter of the valve member is set to be substantially equal to the diameter of the seat portion; The valve opening pressure is adjusted in accordance with the current supplied to the proportional solenoid.

In this damping force-adjusting type hydraulic shock absorber, a damping force is generated by a fixed orifice and a pressure control valve provided in the pilot type damping valve before the pilot type damping valve is opened (low piston speed range). The damping force is adjusted before the pilot damping valve is opened by adjusting the opening pressure of the sub-disc valve of the pressure control valve in accordance with the current supplied to the proportional solenoid. Further, it is possible to adjust the valve opening pressure of the auxiliary disk valve and adjust the pressure of the upstream pilot chamber so that the pilot type damping valve acts in the valve closing direction. The damping force can be adjusted, and the adjustment range of the damping force is widened in combination with the adjustment of the damping force in the low-speed range of the piston speed.

[0005]

In the above-mentioned prior art, the pilot damping valve (main disk valve) receives pressure in the valve opening direction during reverse flow (for example, the contraction-side main disk valve opens during the expansion stroke). In the contraction stroke, the extension-side main disk valve receives pressure in the valve opening direction), the main disk valve rises from the seat surface, and the waveform of the damping force characteristic is likely to be disturbed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to prevent a pilot type damping valve (main disc valve) from being lifted up with a simple configuration and to widen an adjustment range of damping force characteristics. An object of the present invention is to provide a hydraulic shock absorber.

[0007]

According to the present invention, there is provided a cylinder filled with an oil, a piston slidably fitted in the cylinder, one end connected to the piston, and the other end connected to the cylinder. A piston rod extending to the outside, a main passage connected to the cylinder and allowing oil to flow by sliding the piston, a pilot damping valve provided in the main passage, and the pilot damping valve A valve member provided on the back surface of the valve member to form a pilot chamber, a cylindrical sliding member slidably fitted to the valve member and abutting on the pilot damping valve, and bypassing a part of the main passage. And a sub-passage provided in communication with the back surface of the valve member from the pilot chamber via a cross-sectional adjustment valve so as to bias the pilot damping valve in the valve closing direction via the sliding member; Forming a hole Disk member, comprising: a damping force-adjustable hydraulic shock absorber, comprising: an outer diameter of the valve member is set to be larger than a diameter of a seat portion on which the pilot-type damping valve is detached and seated; On the back side of the disc member, a disc-shaped member capable of opening and closing the hole of the disc member and having a pressing force for urging the pilot-type damping valve in the valve closing direction via the disc member and the sliding member. The check valve is provided.

[0008]

Next, an embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 3,
This damping force adjusting type hydraulic shock absorber 1 has a double cylinder structure in which an outer cylinder 3 is provided outside a cylinder 2, and a reservoir 4 is formed between the cylinder 2 and the outer cylinder 3. A piston 5 is slidably fitted in the cylinder 2, and the piston 5 divides the inside of the cylinder 2 into two chambers, an upper cylinder chamber 2a and a lower cylinder chamber 2b (a part of a main passage). Is defined. A substantially cylindrical piston bolt 6 is inserted into the piston 5 and fixed by a nut 7. A solenoid case 9 formed at one end of a piston rod 8 is screwed to a large diameter portion 6a formed at a base end of the piston bolt 6, and the other end of the piston rod 8 is connected to a cylinder upper chamber 2a. As described above, the cylinder 2 and the cylinder 3 are inserted into the rod guide 10 and the oil seal 11 mounted on the upper end of the outer cylinder 3, and extend outside the cylinder 2. Cylinder 2
A base valve 12 for partitioning the cylinder lower chamber 2b and the reservoir 4 is provided at the lower end of the cylinder.

The piston 5 is provided with an extension-side oil passage 13 (main passage) and a contraction-side oil passage 14 (main passage) for communicating between the cylinder upper and lower chambers 2a and 2b. Between the piston 5 and the nut 7, an extension-side damping force generating mechanism 15 for controlling the flow of the oil liquid in the extension-side oil passage 13 is provided. Piston 5
And the large-diameter portion 6a of the piston bolt 6
A contraction-side damping force generating mechanism 16 for controlling the flow of the oil liquid 14 is provided. The base valve 12 is provided with oil passages 17 and 18 for communicating the cylinder lower chamber 2b and the reservoir 4 with each other.
A check valve 19 is provided to allow only the flow of the oil liquid from the reservoir 4 side of the cylinder 17 to the cylinder lower chamber 2b side, and is opened when the pressure of the oil liquid in the cylinder lower chamber 2b reaches a predetermined pressure. A disk valve 20 is provided for flowing the oil liquid to the reservoir 4 side through an oil passage 18. An oil liquid is sealed in the cylinder 2, and an oil liquid and a gas of a predetermined pressure are sealed in the reservoir 4.

Next, the extension side damping force generating mechanism 15 and the contraction side damping force generating mechanism 16 will be described. First, the extension side damping force generation mechanism 15 will be described. An annular valve seat 21 having a predetermined outer diameter is provided on the end face of the piston 5 on the side of the cylinder lower chamber 2b.
The main disc valve 22 (pilot type damping valve) is detachably seated on the valve seat 21. An annular valve member 23 having an outer diameter larger than the outer diameter of the valve seat 21 is mounted between the piston 5 and the nut 7 of the piston bolt 6. A substantially cylindrical sliding member 24 is slidably fitted on the outer periphery of the valve member 23. The sliding member 24 is in contact with the main disk valve 22 by a disk member 26 clamped between the valve member 23 and the nut 7. The disk member 26 is a sliding member by elastic force.
The main disk valve 22 is urged in the valve closing direction via 24.

As shown in FIG. 4, a plurality of arc-shaped holes 32 (holes of the disk member) are formed in the disk member 26 so as to be concentric. The holes 32 include a plurality of (two in this embodiment) first holes 32a having a predetermined radius of curvature, and the first holes 32a.
Are larger than the radius of curvature (in this embodiment, 2
And a second hole 32b. Disc member
A substantially annular (or intermittent annular) projection 98 is formed on the valve member 23 so as to reach the portion 26a between the first hole 32a forming portion and the second hole 32b forming portion of the valve member 26.

Further, as shown in FIGS. 4 and 6, a substantially disc-shaped check valve 100 is laminated on the side of the disk member 26 which is separated from the valve member 23 (the back side of the disk member 26). The main disk valve 22 is urged in the valve closing direction via the disk member 26 and the sliding member 24. As shown in FIG. 5, the check valve 100 is formed with an arc-shaped hole 100a, and the outer peripheral end is bent around the hole 100a. Then, in the initial setting state, as shown in FIG.
A deflection T of about 20 to 50 μm is provided. Due to this deflection T, the set load of the main disk valve 22 is obtained, and the outer peripheral end of the check valve 100 is bent to form a gap S between the check valve 100 and the disk member 26.

Between the main disk valve 22 and the valve member 23, there is formed a back pressure chamber 22A for applying the internal pressure in the valve closing direction of the main disk valve 22. The back pressure chamber 22A is connected to the extension side oil passage 13 by a fixed orifice 27 provided in the main disk valve 22. The back pressure chamber 22A is
The oil passages 28 and 29 provided on the side wall of the piston bolt 6, via an extension side pressure control valve 30 (cross-sectional adjustment valve) provided inside the piston bolt 6, the opposite side (back side) of the valve member 23. 1 (lower side in FIG. 1), and through the hole 32 of the disk member 26, the gap S and the hole 100a of the check valve 100 to the cylinder lower chamber 2b.

Next, the compression side damping force generating mechanism 16 will be described. An annular valve seat 33 having an outer diameter of a predetermined size is protruded from an end surface of the piston 5 on the side of the cylinder upper chamber 2a so that a main disk valve 34 (pilot type damping valve) is detachably seated on the valve seat 33. Has become. Large diameter part of piston bolt 6
An annular valve member 35 having an outer diameter larger than the outer diameter of the valve seat 33 is attached between 6a and the piston 5,
A sliding member 36 is slidably fitted on the outer periphery of the valve member 35. The sliding member 36 is in contact with the main disk valve 34 by a disk member 38 clamped between the valve member 35 and the large diameter portion 6a. The disk member 38 urges the main disk valve 34 in the valve closing direction via the sliding member 36 by an elastic force.

As shown in FIG. 4, a plurality of arc-shaped holes 45 (holes of the disk member) are formed in the disk member 38 so as to be concentric. The hole 45 includes a plurality of (two in this embodiment) first holes 45a having a predetermined radius of curvature, and the first holes 45a.
Are larger than the radius of curvature (in this embodiment, 2
And a second hole 45b. Disc member
A substantially annular (or intermittent annular) projection 99 is formed on the valve member 35 so as to reach a portion 38a between the first hole 45a forming portion and the second hole 45b forming portion of the valve member 38.

Further, as shown in FIGS. 2 and 4, a substantially disc-shaped check valve 101 is laminated on the side of the disk member 38 which is separated from the valve member 35 (the back side of the disk member 38). The main disk valve 34 is urged in the valve closing direction via the disk member 38 and the sliding member 36. As shown in FIG. 5, the check valve 101 is formed with an arc-shaped hole 101a, and the outer peripheral end is bent around the hole 101a. In the initial setting state, the disk member 38
A flexure T (see FIG. 6) is provided in the same manner as in FIG. Due to this bending T, the set load of the main disk valve 34 is obtained, and the outer peripheral end side of the check valve 101 is bent to form a gap S (see FIG. 6) between the check valve 101 and the disk member 38.

A back pressure chamber 39 is formed between the main disk valve 34 and the valve member 35 to apply the internal pressure in the valve closing direction of the main disk valve 34. The back pressure chamber 39 is connected to the compression-side oil passage 14 by a fixed orifice 40 provided in the main disk valve 34. The back pressure chamber 39 is connected to a compression side pressure control valve 43 provided inside the piston bolt 6 by oil passages 41 and 42 provided on the side wall of the piston bolt 6.
(Cross section adjusting valve), the valve member 35 is communicated with the opposite side (rear side, upper side in FIG. 1) of the valve member 35, and the hole 45 of the disk member 38,
It communicates with the cylinder upper chamber 2a through the gap S and the hole 101a of the check valve 101.

The expansion-side and compression-side pressure control valves 30, 43 will be described. In the piston bolt 6, there is an oil passage 2
Small-diameter bores 46 are formed with openings 8 and 41, and large-diameter bores 47 and 48 are formed on both sides (lower and upper sides of FIG. 1) with oil passages 29 and 42, respectively. An annular valve seat 49, 50 is formed by a step between each of the valve seats 47, 48. A cylindrical slider 51 is slidably fitted in the small-diameter bore 46 of the piston bolt 6, and an oil passage is provided between the small-diameter portion formed at both ends of the slider 51 and the small-diameter bore 46, respectively. Annular valve chambers 52 and 53 communicating with 28 and 41 are formed. At both ends of the slider 51,
Sub disc valves 54 and 55 which are separated from and seated on the valve seats 49 and 50 are attached by retainers 56 and 57 which are press-fitted into the slider 51.

A proportional solenoid 58 is provided in the solenoid case 9, and the distal end of an operating rod 60 connected to the plunger 59 abuts on a retainer 57 attached to one end of the slider 51. I have. Piston bolt 6
The large-diameter bore 47 has an adjustment plug 61 that closes the tip.
And a lock nut 62 screwed therein, a compression spring 63 interposed between a retainer 56 attached to the other end of the slider 51 and the adjustment plug 61, and a rear end of a plunger 59 of the proportional solenoid 9. By the spring force of the compression spring 64 that presses
The slider 51 is elastically held. Retainers 56, 57
Are provided with oil passages 67 and 68 for communicating between oil chambers 65 and 66 formed on both sides of the slider 51 to balance pressures applied to both ends of the slider 51.

The small diameter bores 46 in the valve chambers 52, 53 of the piston bolt 6 are provided with steps 69, 70 at positions in the valve chambers 52, 53, respectively. Step 7
The pressure receiving area A ₂ of the auxiliary disk valves 54 and 55 (the pressure receiving area that generates a thrust in the valve opening direction on the slider 51) than the pressure receiving area A ₁ (the pressure receiving area that generates a thrust in the valve closing direction on the slider 51) (Not shown) is larger.

The lead wire 74 of the coil 73 of the proportional solenoid 58
Is extended to the outside through the hollow piston rod 8, and can be energized from a terminal connected to the distal end thereof. Normally, the slider 51 is
3 and 64 make both secondary disc valves 54 and 55 have valve seats 4
When the coil 73 is energized, one of the auxiliary disc valves 54, 55 is closed in the direction and thrust corresponding to the energized current by the proportional solenoid 58 by energizing the coil 73. The other is selectively biased in the valve opening direction. The initial position of the slider 51 can be adjusted by the adjustment plug 61 and the lock nut 62.

The operation of the embodiment constructed as described above will be described below.

During the extension stroke of the piston rod 6, as the piston 5 moves, the oil liquid in the cylinder upper chamber 2a is pressurized, and the main disk valve 22 of the extension-side damping force generating mechanism 15
Before opening the valve (low piston speed range), the expansion side oil passage 13, the fixed orifice 27 of the main disk valve 22, the back pressure chamber 22A, the oil passage 28, the expansion side pressure control valve 30, the oil passage 29, the hole 32,
It flows to the cylinder lower chamber 2b side through the gap S and the hole 100a of the check valve 100. When the pressure on the cylinder upper chamber 2a side reaches the valve opening pressure of the main disk valve 22 (high-speed region of the piston speed), the main disk valve 22 opens and the extension side oil passage 13
The oil liquid flows directly from the cylinder chamber 2b to the lower chamber 2b. It should be noted that the oil liquid corresponding to the piston rod 6 withdrawing from the cylinder 2 flows from the reservoir 4 to the cylinder lower chamber 2b by opening the check valve 19 of the oil passage 17 of the base valve 12.

Thus, before the main disk valve 22 is opened (low piston speed range), the fixed orifice
The damping force is generated by the extension pressure control valve 30 and the extension side pressure control valve 30.
In the extension side pressure control valve 30, a slider is provided in the valve chamber 52.
Since relative pressure receiving area A ₁ of the step portion 71 of the 51 larger pressure receiving area A ₂ of the sub disk valve 54, by the pressure receiving area difference between these axially, the slider 51 in the direction of opening the sub disk valve 54 Thrust is generated. On the other hand, the proportional solenoid 58
By biasing the slider 51 in the valve closing direction of the secondary disk valve 54 to adjust the valve opening pressure of the secondary disk valve 54 according to the current supplied to the coil 73, the main disk valve 22 is opened before opening. The damping force in the low-speed range of the piston speed) can be directly controlled regardless of the piston speed.

By adjusting the valve opening pressure of the sub disc valve 54, the upstream back pressure chamber is adjusted in accordance with the pressure.
22A is adjusted, and the pressure in the back pressure chamber 22A acts in the valve closing direction as the pilot pressure of the main disc valve 22, so that the opening pressure of the main disc valve 22 and the opening pressure of the sub disc valve 54 are reduced. Similarly, the damping force in the high speed range of the piston speed can be simultaneously adjusted.

An annular valve member 23 having an outer diameter larger than the outer diameter of the valve seat 21 on which the main disc valve 22 of the extension-side damping force generating mechanism 15 is detachably seated is mounted. In the extension stroke of the main disk valve 22 and the valve member 23 of the extension side damping force generating mechanism 15 (and the sliding member 24 fitted to the valve member 23), the hydraulic pressure is applied to the main disk valve 22 from the valve opening direction. Acts in the valve closing direction. Therefore, even if the valve set load of the disk member 26 is almost zero, a high damping force can be generated at the time of extension-side hardening, and the adjustment range of the damping force can be widened accordingly. On the other hand, when the main disk valve 22 and the valve member 23
With respect to (the sliding member 24 fitted to the valve member 23), the hydraulic pressure acts on the main disk valve 22 in the valve opening direction to lift the main disk valve 22 from the valve seat 21. It is canceled by the urging force of the disk member 26 and the check valve 100 and the hydraulic pressure of the cylinder lower chamber 2b acting on the check valve 100, thereby preventing the main disk valve 22 from floating.

Further, a protrusion 98 is formed on the valve member 23. In the reverse flow (shrinkage stroke) to the extension-side damping force generating mechanism 15, the protrusion 98 comes into contact with the disk member 26 to bend the disk member 26. Since the deformation is regulated, it is possible to reliably prevent the disk member 26 from being damaged.

During the contraction stroke of the piston rod 6, the check valve 19 of the base valve 12 is closed with the movement of the piston 5, and the oil liquid in the cylinder lower chamber 2b is pressurized.
Before the main disk valve 34 of the compression side damping force generating mechanism 16 is opened (low speed range of the piston speed), the compression side oil passage 14
Fixed orifice 40 of main disk valve 34, back pressure chamber 39, oil passage 41, compression side pressure control valve 43, oil passage 42, check valve 44 and hole 45
Through the cylinder upper chamber 2a. Then, when the pressure on the cylinder lower chamber 2b side reaches the valve opening pressure of the main disk valve 34 (high-speed range of the piston speed), the main disk valve 34 opens, and the oil liquid flows from the contraction side oil passage 14 to the cylinder upper chamber 2a. Flows directly. It should be noted that the amount of oil that the piston rod 6 has penetrated into the cylinder 2 flows from the cylinder lower chamber 2 b to the oil passage of the base valve 12.
The disc valve 20 of 18 is opened to flow to the reservoir 4.

Thus, before the main disk valve 34 is opened (low piston speed range), the fixed orifice
The damping force is generated by 40 and the contraction side pressure control valve 43.
In the compression side pressure control valve 43, a slider is provided in the valve chamber 53.
Since relative pressure receiving area A ₁ of the step portion 72 of the 51 larger pressure receiving area A ₂ of the sub disk valve 55, by its pressure receiving area difference, the valve opening direction of thrust of the sub disk valve 55 is caused to slide 51. On the other hand, the slider 51 is urged by the proportional solenoid 58 in the valve closing direction of the sub disc valve 55,
By adjusting the valve opening pressure of the sub-disk valve 55 in accordance with the current supplied to the coil 73, the damping force before the main disk valve 34 is opened (low piston speed range) is directly controlled regardless of the piston speed. be able to.

By adjusting the valve opening pressure of the sub disc valve 55, the upstream back pressure chamber is adjusted in accordance with the pressure.
The pressure of the back pressure chamber 39 is adjusted as the pilot pressure of the main disc valve 34 in the valve closing direction, so that the opening pressure of the main disc valve 34 together with the opening pressure of the sub disc valve 55 is reduced. Similarly, the damping force in the high speed range of the piston speed can be simultaneously adjusted.

An annular valve member 35 having an outer diameter larger than the outer diameter of the valve seat 33 on which the main disk valve 34 of the compression side damping force generating mechanism 16 is detachably seated is mounted. During the compression stroke of the piston rod 6, the hydraulic pressure is applied to the main disk valve 34 and the valve member 35 of the compression side damping force generating mechanism 16 (and the sliding member 36 fitted to the valve member 35). The valve 34 acts in the valve closing direction rather than the valve opening direction. For this reason, even if the valve set load of the disk member 38 is almost zero, a high damping force can be generated at the time of hardening on the contraction side, and the adjustment range of the damping force can be widened accordingly. On the other hand, the compression side damping force generation mechanism
With respect to the main disk valve 34 and the valve member 35 (and, consequently, the sliding member 36 fitted to the valve member 35), the hydraulic pressure is applied to the main disk valve 34 in the reverse flow (extension stroke) to the main disk valve 34.
Acts in the valve opening direction to lift the main disk valve 34 from the valve seat 33. This lifting force is caused by the urging force of the disk member 38 and the check valve 101 and the check valve 101.
Is canceled by the hydraulic pressure of the cylinder upper chamber 2a acting on the main disk valve 34, thereby preventing the main disk valve 34 from floating.

Further, a projection 99 is formed on the valve member 35, and in the reverse flow (extension stroke) to the contraction-side damping force generating mechanism 16 described above, the projection 99 comes into contact with the disk member 38 to bend the disk member 38. Since the deformation is regulated, it is possible to reliably prevent the disk member 38 from being damaged.

As described above, the damping force can be adjusted from the low speed range to the high speed range of the piston speed, and the outer diameter of the valve members 23, 35 can be made smaller than the diameter of the valve seats 21, 33. By setting it large, the adjustment range of the damping force can be widened. The expansion-side and compression-side pressure control valves 30 and 43 can provide an appropriate damping force due to valve characteristics even in a low piston speed range, so that the damping force is insufficient in a low piston speed range and a damping force in a high speed range. Can be prevented from rising excessively. If the pressure in the back pressure chambers 22A and 39 rises sharply due to sudden input caused by thrust from the road surface, etc., the auxiliary disk valve 5 of the expansion side and compression side pressure control valves 30 and 43
The pressure of the back pressure chambers 22A, 39 can be quickly relieved to the oil chambers 63, 66 by bending the outer peripheral portions from the valve seats 49, 50 by bending the outer peripheral portions of the 4, 55, so that the damping force is sharply increased. Ascent can be suppressed, and the riding comfort of the vehicle can be improved.

Step 7 of slider 51 in valve chambers 52, 53
Since the damping force is controlled by the balance between the thrust generated on the slider 51 by the difference in pressure receiving area between the first and second disk valves 54 and 55 and the thrust of the proportional solenoid 58, by reducing the difference in pressure receiving area, The load on the proportional solenoid 58 can be reduced, and the size and weight can be reduced. Further, since the damping force is directly controlled by opening and closing the sub-disc valves 54 and 55 which are pressure control valves, the influence of the dimensional tolerance of each part is smaller than that of the variable orifice, and a stable damping force can be obtained.

The slider 51 is a coil of a proportional solenoid 58
A position to open both the sub-disks 54 and 55 by the current supplied to the 73 (soft on both the extension side and the contraction side), and a position to close one of them and open the other (soft on the extension side and hard on the contraction side, Alternatively, since it is possible to take the extension side hard and the compression side software, it is possible to obtain the extension side compression side reversal characteristic suitable for semi-active suspension control based on the so-called skyhook theory.

In the present embodiment, the extension-side damping force generation mechanism
15 and the contraction-side damping force generating mechanism 16 are provided in the piston portion, but instead of this, a damping type in which the extension-side damping force generating mechanism and the contraction-side damping force generating mechanism are provided on the outer peripheral side of the cylinder. The present invention may be applied to a force-adjustable hydraulic shock absorber. Further, in the present embodiment, the case where the cross-section adjustment valve is a pressure control valve is described as an example, but a flow control type cross-section adjustment valve may be used instead.

[0037]

According to the first aspect of the present invention, the outer diameter of the valve member is set to be larger than the diameter of the seat portion on which the pilot type damping valve is detached and seated, so that the valve member can be moved forward (for example, In the extension stroke), the hydraulic pressure acts on the pilot type damping valve and the valve member (and the sliding member fitted to the valve member) in the closing direction of the pilot type damping valve. Even if it is set to zero, a high damping force can be generated at the time of forward flow (for example, extension stroke), and the adjustment range of the damping force can be widened accordingly. On the other hand, in the reverse flow (for example, a contraction stroke) with respect to the pilot-type damping valve, the hydraulic pressure acts on the pilot-type damping valve in the valve opening direction with respect to the pilot-type damping valve and the valve member (hence, the sliding member). The damping valve is lifted from the seat, but this lifting force is
It is canceled by the urging force of the disk member and the check valve and the hydraulic pressure of the cylinder lower chamber acting on the check valve, thereby preventing the pilot type damping valve from floating.

[Brief description of the drawings]

FIG. 1 is an enlarged longitudinal sectional view showing a main part of a damping force adjusting type hydraulic shock absorber according to an embodiment of the present invention.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is a longitudinal sectional view of the entire apparatus shown in FIGS. 1 and 2;

FIG. 4 is a plan view showing the sheet disk of FIGS. 1 and 2;

FIG. 5 is a plan view showing the check valve of FIGS. 1 and 2;

6 is a cross-sectional view schematically showing an assembled state of the seat disk of FIG. 4 and the check valve of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic shock absorber with damping force adjustment 2 Cylinder 2a Upper cylinder chamber (main passage) 2b Lower cylinder chamber (main passage) 5 Piston 8 Piston rod 13 Extension-side oil passage (main passage) 14 Contraction-side oil passage (main passage) 21 , 33 Valve seat (seat part) 22,34 Main disk valve (pilot type damping valve) 22A, 39 Back pressure chamber (pilot chamber) 23,35 Valve member 24,36 Sliding member 26,38 Disk member 27,40 Fixed Orifice 30 Extension side pressure control valve (cross-section adjustment valve) 32,45 hole (hole in disc member) 43 Retraction side pressure control valve (cross-section adjustment valve) 100,101 Check valve

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Takao Nakatate 1116 Kozono, Ayase-shi, Kanagawa F-term in Tokiko Co., Ltd. Sagami Plant (reference) 3J069 AA54 EE28 EE43

Claims (1)

[Claims] 1. A cylinder filled with an oil liquid, a piston slidably fitted in the cylinder, and a piston having one end connected to the piston and the other end extending outside the cylinder. A rod, a main passage connected to the cylinder, and through which the oil flows by sliding the piston, a pilot damping valve provided in the main passage, and a pilot chamber provided on the back of the pilot damping valve. A valve member to be formed, a cylindrical sliding member which is slidably fitted to the valve member and abuts on the pilot type damping valve, and crosses from the pilot chamber so as to bypass a part of the main passage. A sub-passage provided in communication with the back surface of the valve member through a surface adjustment valve, and a disk member which urges the pilot-type damping valve in the valve closing direction via the sliding member and has a hole, Equipped A damping force-adjustable hydraulic shock absorber, wherein an outer diameter of the valve member is set to be larger than a diameter of a seat portion on which the pilot-type damping valve is detached and seated, and a rear side of the disk member. A disc-shaped check valve that can open and close the hole of the disc member and has a pressing force for urging the pilot-type damping valve in the valve closing direction via the disc member and the sliding member. A damping force adjustable hydraulic shock absorber.