JPH07103279A - Damping force adjustable hydraulic shock absorber - Google Patents

Abstract

(57) [Abstract] [Purpose] The damping force can be adjusted by changing the flow passage area of the orifice passage that allows the rod guide to communicate between the reservoir chamber and the rod-side oil chamber. [Structure] The rod guide 19 is composed of a guide cylinder 20 and a rod guide main body 21 inserted into an insertion hole 20A of the guide cylinder 20 so as to be relatively rotatable. Further, an orifice passage 26 is formed in the radial direction, and the orifice passage 26 is composed of an orifice passage portion 26A having a large diameter and an orifice 27 having a different diameter to be selected. Then, the damping force is adjusted by rotating the rod guide body 21 to appropriately select the orifice 27 and changing the flow passage area to adjust the damping force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic shock absorber that is preferably used for damping vehicle vibrations, loading on health equipment, seat dampers, and the like. And a damping force adjusting hydraulic shock absorber.

[0002]

2. Description of the Related Art Generally, a hydraulic shock absorber as disclosed in, for example, Japanese Utility Model Laid-Open No. 57-45483 (hereinafter referred to as "prior art") is known for adjusting the damping force characteristic on the rod guide side. .

In this hydraulic shock absorber according to the prior art, an upper oil chamber formed by slidably inserting a piston into an inner cylinder composed of an inner and outer double cylinders and an oil chamber in the outer cylinder are connected in the middle of a passage. Is provided with an opening area adjusting member for the passage, and a relief valve or a leaf valve is arranged in front of or behind the opening area adjusting member.

In this prior art, a passage for communicating the upper oil chamber with the oil chamber of the outer cylinder is provided in the upper lid, and a cylindrical hollow portion formed in the radial direction is provided in the middle of the passage. A cylindrical plug as a member for adjusting the opening area of the passage is rotatably fitted from the outside. This plug is provided with a relief valve and a leaf valve in its hollow portion that closes the outlet of the passage by the elastic force of a spring, and the side wall of the hollow portion has a plurality of orifices with different diameters on the same circumference to make the passage areas different. Has been drilled. These orifices allow the opening area of the passage to be selected by moving the plug with a tool such as a screwdriver, and the opening area can be adjusted by the diameter of the selected orifice.

In this way, by rotating the plug and selecting the orifice, the extension side of the piston rod,
A desired damping force can be generated on the contraction side.

[0006]

By the way, in the above-mentioned prior art, in order to adjust the damping force, the plug must be rotated by using a tool such as a screwdriver, which makes the adjustment work troublesome. There is a problem.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a damping force adjustable hydraulic shock absorber capable of easily adjusting the damping force.

[0008]

In order to solve the above-mentioned problems, a damping force adjustable hydraulic shock absorber adopted by the present invention is
An outer cylinder whose both ends are closed; an inner cylinder that is disposed inside the outer cylinder and forms a reservoir chamber between the outer cylinder; a rod guide that is disposed at one end of the inner cylinder; A piston that is slidably inserted into the inner cylinder and that defines the inside of the inner cylinder into a rod-side oil chamber and a bottom-side oil chamber, and one end side of which is fixed to the piston,
A piston rod having the other end protruding outside the outer cylinder through the rod guide, and the piston or the piston rod, which is provided at least between the rod-side oil chamber and the bottom-side oil chamber when the piston rod extends. And a damping force generation mechanism for generating a damping force by the pressure oil flowing through the.

The features of the configuration adopted by the present invention are as follows:
An outer peripheral side of the rod guide is fitted into the outer cylinder and the inner cylinder, and a guide cylinder having an insertion hole formed on the inner peripheral side is inserted into the insertion hole of the guide cylinder so as to be rotatable relative to each other. The rod guide body is formed on the circumferential side as a rod sliding hole for the piston rod, and an orifice passage that connects the reservoir chamber and the rod-side oil chamber is formed in the rod guide body and the guide cylinder. The orifice passage has a structure in which the flow passage area is changed by rotating the rod guide body relative to the guide cylinder.

[0010]

By rotating the rod guide body relative to the guide cylinder, the flow passage area of the orifice passage that connects the reservoir chamber and the rod side oil chamber is changed. As a result, the flow resistance of the pressure oil that communicates the reservoir chamber and the rod-side oil chamber can be changed, and the damping force can be changed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

First, a first embodiment is shown in FIGS.

In the figure, reference numeral 1 denotes an outer cylinder which constitutes the main body of the hydraulic shock absorber, the outer cylinder 1 is closed at the lower side by a bottom cap 2 and at the upper end by a rod guide 19 described later. Reference numeral 3 denotes a mounting bracket fixed to the bottom cap 2 by means such as welding. The mounting bracket 3 is adapted to mount the outer cylinder 1 on the axle side (not shown) of the vehicle. Reference numeral 4 denotes an inner cylinder coaxially arranged in the outer cylinder 1. The inner cylinder 4 extends vertically in the outer cylinder 1 and includes the rod guide 19 and a valve body 14 of a bottom valve 13 described later. It is fixed in the outer cylinder 1 via the. A reservoir chamber C is defined between the outer cylinder 1 and the inner cylinder 4.

Reference numeral 5 denotes a piston slidably fitted in the inner cylinder 4, and the piston 5 is arranged inside the inner cylinder 4 in the rod side oil chamber A.
And a bottom side oil chamber B, and oil holes 5A, 5A are formed so as to connect the oil chambers A, B to each other.

Reference numeral 6 denotes a piston rod having a lower end side fixed to the piston 5 and formed in a stepped columnar shape. The upper end side of the piston rod 6 projects outside the outer cylinder 1 through a rod guide 19, and the projection thereof. The end side is attached to the vehicle body or the like of the vehicle (none of which is shown). Further, a nut 7 is screwed on the lower end side of the piston rod 6, and the nut 7 mounts the piston 5 on the piston rod 6 together with a guide 9 described later.

Reference numeral 8 denotes a piston valve which constitutes an extension side damping force generating mechanism provided on the upper side surface of the piston 5, and the piston valve 8 is composed of a plurality of disc valves sandwiched between the piston valve 8 and a cylindrical guide 9. 10 and the disc valve 10
A retainer 11 that is provided on the upper side of the so as to be slidably guided by the guide 9 and has oil passages 11A and 11A;
It is generally composed of a biasing spring 12 that biases the retainer 11 from above.

In the piston valve 8 thus constructed, the inner peripheral side of the disc valve 10 is bent downward by the pressure oil in the rod side oil chamber A during the extension stroke of the piston rod 6, and this pressure oil is A damping force is generated by circulating the oil into the bottom side oil chamber B. On the other hand, piston rod 6
During the contraction stroke, the retainer 11 is displaced against the spring 12 to act as a check valve that allows the pressure oil in the bottom side oil chamber B to flow into the rod side oil chamber A without generating a damping force. To do.

Reference numeral 13 denotes a bottom valve which is located on the inner peripheral side of the lower end of the inner cylinder 4 and constitutes a reducing-side damping force generating valve provided between the inner cylinder 4 and the bottom cap 2. Reference numeral 13 constitutes a main body of the bottom valve 13, and a valve main body 14 that defines a bottom side oil chamber B and a reservoir chamber C,
Check valve body 15 provided on the upper surface side of the valve body 14
A spring 16 disposed above the check valve body 15 for urging the check valve body 15 downward, a disc valve 17 provided on the lower surface side of the valve body 14, and the check valve body 15 , A pin 16 for fixing the spring 16, the disc valve 17 and the like to the valve body 14 in general.

Here, the valve main body 14 is formed in a stepped disc shape, and is located radially outward in the axial direction and is provided with large diameter first oil passages 14A, 14A ,. The second oil passages 14B, 14B having a small diameter are bored on the radially inner side.

In the bottom valve 13 thus constructed, the pressure in the bottom side oil chamber B becomes lower than that in the reservoir chamber C during the extension stroke of the piston rod 6,
The pressure oil in the reservoir chamber C acts on the check valve body 15 via the respective oil passages 14A of the valve body 14 to open the check valve body 15 against the spring force of the spring 16 to open the bottom side oil chamber. It flows into B. On the other hand, during the compression stroke of the piston rod 6, the pressure in the bottom side oil chamber B becomes high, so that the pressure oil in the bottom side oil chamber B opens the disc valve 17 via each oil passage 14B of the valve body 14. As a result, the fluid flows into the reservoir chamber C while generating a predetermined damping force. In addition, the check valve body 15 is controlled by the pressure in the bottom side oil chamber B, and
4, and keeps closing each oil passage 14A.

Reference numeral 19 denotes a rod guide according to the present embodiment. As shown in FIG. 2, the rod guide 19 has an outer peripheral side inserted into the outer cylinder 1 and the inner cylinder 4 and an inner peripheral side insertion hole 20A. A guide cylinder 20 having a stepped cylindrical shape formed with a groove, and a rod slide hole 2 for the piston rod 6 which is inserted into an insertion hole 20A of the guide cylinder 20 so as to be relatively rotatable.
The rod guide main body 21 has a size of 1A.

Here, the lower side of the guide cylinder 20 is the inner cylinder 4.
Is a small-diameter cylindrical portion 20B to which the upper end is fixed, and the upper portion is a large-diameter cylindrical portion 2 to which the outer cylinder 1 is caulked and fixed via a ring 22.
It is 0C. Further, as shown in FIG. 4, the step portion located between the large-diameter cylindrical portion 20C and the small-diameter cylindrical portion 20B has an opening angle of about 90 ° with which a rotation regulating pin 28 described later is engaged. The arc-shaped engaging hole 20D is formed so as to open upward.

The lower side of the rod guide body 21 is a cylindrical shutter 21B slidably fitted in the small-diameter cylindrical portion 20B of the guide cylinder 20, and the upper side thereof is the seal member 2.
It becomes an annular accommodation portion 21C for accommodating 3 etc., and the accommodation portion 2
A knurled portion 21D is formed on the outer peripheral surface of 1C. Then, the sealing member 23 is formed by caulking the tip of the accommodation portion 21C inward in the radial direction via a ring 24.
Are to be accommodated.

Reference numeral 25 denotes an oil passage bored in the axial direction of the rod guide 19, and the oil passage 25 connects the reservoir chamber C and the accommodating portion 21C. And
The oil passage 25 includes a first passage portion 25A formed in the guide cylinder 20, a second passage portion 25B formed in the rod guide body 21, and an annular portion 25C for communicating the passage portions 25A, 25B. Become.

Reference numeral 26 denotes an orifice passage according to this embodiment. The orifice passage 26 is bored in the radial direction of the rod guide 19 so that the reservoir chamber C and the rod-side oil chamber A communicate with each other. Then, the orifice passage 2
As shown in FIG. 3, 6 is a small-diameter cylinder portion 20B of the guide cylinder 20.
Large diameter orifice passage portion 26A bored in the radial direction of
And, for example, three orifices 27A, 27B, 27C (hereinafter collectively referred to as "orifice 27") having different diameters that are formed in the radial direction of the shutter 21B of the rod guide body 21.

Reference numeral 28 indicates a rotation restricting pin, and the rotation restricting pin 28 restricts the rotation angle of the rod guide body 21 with respect to the guide cylinder 20. Further, the engaging projections 20D1 and 20D are provided on the bottom of the arcuate engagement hole 20D which is the engaged portion of the rotation restricting pin 28 at the center in the longitudinal direction.
1 is formed so that the orifice 27B can be easily positioned.

In the rod guide 19 according to the present embodiment constructed as described above, one of the three orifices 27 is selected by rotating the rod guide body 21 relative to the guide cylinder 20. It is possible to set the flow passage area of the orifice passage 26 by the orifice 27.

In other words, when it is desired to set it to be hard, the small diameter orifice 27A is selected in order to increase the flow passage resistance when the pressure oil flows. Further, when it is desired to set the medium, the medium-diameter orifice 27B that provides a medium flow resistance when the pressure oil flows is selected. Further, when the soft setting is desired, the large diameter orifice 27C is selected in order to reduce the flow path resistance when the pressure oil flows.

Reference numeral 29 denotes a rubber cylinder whose upper and lower sides are fixed to the outer peripheral surface of the inner cylinder 4. The rubber cylinder 29 is filled with air, and the space between the inner cylinder 4 and the outer cylinder 1 is provided in the reservoir chamber C. And air chamber D
It is designed to be defined as And this air chamber D
Is collapsed to absorb the invading volume when the piston rod 6 contracts.

The damping force adjusting type hydraulic shock absorber according to the present embodiment has the above-mentioned structure, and its operation will be described below.

First, when the piston speed is low when the piston rod 6 extends, the pressure oil in the rod side oil chamber A flows into the reservoir chamber C through the orifice passage 26 provided in the rod guide 19. At this time, a damping force is generated by the orifice 27. When the piston speed increases, the disc valve 10 provided on the piston 5 opens, and the disc valve 10 generates a damping force.

On the other hand, when the piston speed is slow when the piston rod 6 is contracted, the retainer 11 of the piston valve 8 is
Moves upward against the spring 12 to open the valve, and the rod side oil chamber A and the bottom side oil chamber B communicate with each other to have substantially the same pressure, and the pressure corresponding to the intrusion volume of the piston rod 6 is applied to the rod guide 19. It flows into the reservoir chamber C through the orifice passage 26 provided. At this time, a damping force is generated by the orifice 27. When the piston speed increases, the disc valve 17 provided on the bottom side opens, and the disc valve 17 generates a damping force.

By adjusting the flow passage area of the orifice passage 26 provided in the rod guide 19, the damping force is adjusted by the flow passage resistance of the pressure oil flowing through the orifice 27.

Thus, in this embodiment, the shutter 21
By selecting the orifice 27 of B, a damping force adjustable hydraulic shock absorber capable of generating three types of damping forces can be obtained, and the orifice 27A (minimum diameter, hard)
When is selected, the flow path resistance becomes high and a large damping force is generated. Further, when the orifice 27B (intermediate diameter, medium) is selected, the flow path resistance becomes intermediate, and an intermediate damping force is generated. Furthermore, when the orifice 27C (maximum diameter, soft) is selected, the flow path resistance becomes low,
A small damping force can be generated.

The method of selecting the orifice 27 is as follows.
The knurled portion 21D of the rod guide body 21 forming the rod guide 19 may be rotated. Further, the rotation restricting pin 28 rotates in the arc-shaped engagement hole 20D as the rod guide body 21 rotates, and is positioned in the engagement hole 20D to reliably select the orifice 27. Is able to.

However, according to the present embodiment, by providing the orifice flow passage 26 whose flow passage area can be adjusted by rotating the rod guide body 21 on the rod guide 19, as in the prior art, the screwdriver can be used. Since it is not necessary to adjust the damping force using a tool such as the above, the adjustment work can be easily performed.

Further, when used in a vehicle as in the embodiment, the damping force can be set according to the running state of the vehicle, and the riding comfort can be improved.

In the above embodiment, the shutter 21B of the rod guide body 21 has the orifice 27 which can be switched among three stages of hard, medium and soft. However, the present invention is not limited to this, and a plurality of plural orifices can be used. By appropriately setting the number of orifices 27, it is possible to switch between two stages or four stages or more. Further, in the case of hard, the orifice 27 may be omitted so as to prevent the flow of the pressure oil from the reservoir chamber C to the rod side oil chamber A. Further, the orifice 27 may be formed as one elongated hole whose flow passage area changes continuously by rotation.

Next, a second embodiment according to the present invention is shown in FIGS. 5 to 7, which is characterized in that the rod guide body is composed of two members and the flow passage area of the pressure oil is changed. The orifice to be made is one elongated hole that continuously changes with the rotation. In this embodiment, the same components as those of the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, reference numeral 31 denotes a rod guide according to this embodiment. As shown in FIG. 6, the rod guide 31 has its outer peripheral side inserted into the outer cylinder 1 and the inner cylinder 4 and the inner peripheral side. A guide cylinder 32, which will be described later and has a stepped cylinder shape with a hole 32A formed therein.
And a rod guide body 33, which is inserted into the insertion hole 32A of the guide cylinder 32 so as to be relatively rotatable, and includes a rotating member 34, a connecting ring 35, and a shutter 36.

Reference numeral 32 denotes a guide cylinder. The guide cylinder 32 has a small diameter cylinder 32B fixed to the upper end of the inner cylinder 4 on the lower side and a large diameter cylinder 32C fixed to the upper end of the outer cylinder 1 on the upper side.
Therefore, the connecting ring 35 and the like are positioned on the inner peripheral side step portion 32D of the small diameter cylindrical portion 32B and the large diameter cylindrical portion 32C.

Reference numeral 34 denotes a rotating member, which is formed in a stepped cylinder shape and has an upper side which is a flange portion 34A.
A rotation lever 43, which will be described later, is provided on the outer peripheral surface of the flange portion 34A.
Is fixed, and a connecting ring 35 is connected to the inner peripheral side of the lower cylindrical portion 34B via a spline connection. Also,
The lower inner circumference of the flange portion 34A serves as a housing portion 34C for housing a seal member 37 described later.

Reference numeral 35 denotes a connecting ring, and the connecting ring 3
The rotating member 34 and the shutter 36 are connected to each other on the inner and outer peripheral sides of the rotating member 3 through spline coupling.
The rotation of 4 is transmitted to the shutter 36.

Reference numeral 36 denotes a shutter, and the shutter 36
7 is formed in a stepped cylinder shape, a spline 36B is formed on the outer peripheral surface of the upper small-diameter cylindrical portion 36A, and a rod sliding hole 36C on which the piston rod 6 slides on the inner peripheral side.
Becomes Further, an orifice 41, which will be described later, is formed in the lower large-diameter cylindrical portion 36D.

Reference numeral 37 denotes a seal member provided on the inner peripheral side of the rotating member 34, and the seal member 37 is the spring 3
The sealability is enhanced by pressing the piston rod 6 toward the piston rod 6 side.

Reference numeral 39 denotes an oil passage bored in the axial direction of the rod guide 31. The oil passage 39 connects the reservoir chamber C and the accommodating portion 34C, and the oil passage 39 is formed in the guide cylinder 32. The first passage portion 39A, the second passage portion 39B formed in the connecting ring 35, and the passage portions 39A, 39B.
And an annular portion 39C communicating with each other.

Reference numeral 40 denotes an orifice passage according to this embodiment. The orifice passage 40 is bored in the radial direction of the rod guide 31 and connects the reservoir chamber C and the rod side oil chamber A, and is shown in FIG. As described above, the large diameter orifice passage portion 40A is provided in the small diameter tubular portion 32B of the guide tube 32 in the radial direction, and the orifice 41 is provided in the radial direction of the shutter 36 constituting the rod guide body 33. .

Here, as shown in FIG. 7, the orifice 41 is located in the circumferential direction of the large diameter cylindrical portion 36D, the right side is a large diameter portion 41A which becomes longer in the axial direction and the left side is a small diameter portion which becomes shorter in the axial direction. 41B, which is formed so as to be gradually shortened from the right side to the left side, and the length of the orifice 41 is the large-diameter cylindrical portion 36
The length is about 1/4 of the entire circumference of D.

Reference numeral 42 denotes an outer shell provided at the tip of the protruding side of the piston rod 6, and the outer shell 42 protects the outer peripheral surface of the piston rod 6 protruding from the rod guide 31 from flying stones from the outside. ing.

Reference numeral 43 denotes a turning lever attached to the turning member 34 so as to project from the lower side of the outer shell 42. By turning the turning lever 43, the turning member 34 and the connecting ring are shown. The flow passage area of the orifice passage 40 can be changed by rotating the shutter 35 and the shutter 36 to select the position of the orifice 41.

The damping force adjusting type hydraulic shock absorber of the present embodiment constructed as described above also operates similarly to the hydraulic shock absorber of the first embodiment.

That is, when the piston speed when the piston rod 6 is extended is slow, the pressure oil in the rod side oil chamber A flows into the reservoir chamber C through the orifice passage 40 provided in the rod guide 19. At this time, a damping force is generated by the orifice 41. When the piston speed increases, the disc valve 10 provided on the piston 5 opens, and the disc valve 10 generates a damping force.

On the other hand, when the piston speed is low when the piston rod 6 is contracted, the retainer 11 of the piston valve 8 is
Moves upward against the spring 12 and opens the valve, and the rod side oil chamber A and the bottom side oil chamber B communicate with each other to have substantially the same pressure, and the pressure corresponding to the intrusion volume of the piston rod 6 is applied to the rod guide 31. It flows into the reservoir chamber C through the orifice passage 40 provided. At this time, a damping force is generated by the orifice 41. When the piston speed increases, the disc valve 17 provided on the bottom side opens, and a damping force is generated by the disc valve 17.

As described above, in this embodiment, the rotating lever 4
By rotating 3 the position of the orifice 41 formed in the shutter 36 is adjusted to adjust the flow passage area flowing through the orifice passage 40. That is, when the large diameter portion 41A of the orifice 41 is in the orifice passage portion 40A, the flow passage area can be increased and the damping force can be softened. On the other hand, when the small diameter portion 41B of the orifice 41 is in the orifice passage portion 40A, the flow passage area can be reduced and the damping force can be made hard. Further, when the intermediate portion of the orifice 41 is in the orifice passage portion 40A, the flow passage area can be set to the intermediate portion and an appropriate damping force can be generated.

Thus, according to this embodiment, unlike the first embodiment, the damping force can be continuously changed,
The degree of freedom in adjusting the damping force can be increased.

In each of the above-mentioned embodiments, the case where the hydraulic shock absorber is used for the suspension for improving the riding comfort of the vehicle has been described, but the present invention is not limited to this, and the load of the steering damper, the seat damper, and the health equipment is not limited to this. Etc. may be used.

[0057]

As described above in detail, according to the present invention, the rod guide is inserted into the guide tube having the insertion hole formed on the inner peripheral side thereof, and is relatively rotatably inserted into the insertion hole of the guide tube. Is
An inner peripheral side is composed of a rod guide body having a rod sliding hole for the piston rod, and the rod guide body and the guide cylinder are formed with an orifice passage for communicating between the reservoir chamber and the rod side oil chamber. The flow passage area of the orifice passage is changed by rotating the rod guide body relative to the guide cylinder. Therefore, the flow passage of the orifice passage is changed by rotating the rod guide body. The damping force can be easily adjusted by changing the resistance.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a damping force adjusting hydraulic shock absorber according to a first embodiment.

FIG. 2 is an enlarged vertical sectional view showing an enlarged main part in FIG.

FIG. 3 is a cross-sectional view as seen from the direction of arrows III-III in FIG.

FIG. 4 is a cross-sectional view as seen from the direction of arrows IV-IV in FIG.

FIG. 5 is a vertical sectional view showing a damping force adjusting hydraulic shock absorber according to a second embodiment.

FIG. 6 is an enlarged vertical sectional view showing an enlarged main part in FIG.

7 is a perspective view showing a shutter in FIG.

[Explanation of symbols]

 1 Outer cylinder 4 Inner cylinder 5 Piston 6 Piston rod 8 Piston valve 13 Bottom valve 19, 31 Rod guide 20, 32 Guide cylinder 20A, 32A Insertion hole 21, 33 Rod guide body 21A, 36C Rod sliding hole 21B, 36 Shutter 26, 40 Orifice passage 26A, 40A Orifice passage portion 27, 41 Orifice 34 Rotating member 35 Connecting ring A Rod side oil chamber B Bottom side oil chamber C Reservoir chamber D Air chamber

Claims (1)

[Claims] 1. An outer cylinder having both ends closed, and an inner cylinder disposed in the outer cylinder and having a reservoir chamber formed between the outer cylinder and the outer cylinder.
A rod guide disposed on one end side of the inner cylinder; a piston slidably fitted in the inner cylinder and defining a rod-side oil chamber and a bottom-side oil chamber in the inner cylinder; One end side is fixed to the piston and the other end side is provided on the piston or the piston rod and protrudes outside the outer cylinder via the rod guide, and the rod side oil chamber is provided at least when the piston rod extends. And a damping force generation mechanism that generates a damping force by the pressure oil flowing between the bottom oil chamber and the bottom side oil chamber, the rod guide is fitted on the outer peripheral side in the outer cylinder and the inner cylinder, From a guide cylinder having an insertion hole formed on the peripheral side, and a rod guide main body having an inner peripheral side which is a rod sliding hole for the piston rod, which is relatively rotatably inserted into the insertion hole of the guide cylinder. Constituting the rod moth An orifice passage that connects the reservoir chamber and the rod-side oil chamber is formed in the guide body and the guide cylinder, and the orifice passage is formed by rotating the rod guide body relative to the guide cylinder. A damping force adjustable hydraulic shock absorber characterized in that the road area changes.