JPH0647144Y2 - Variable damping force type hydraulic shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a hydraulic shock absorber that is suitable for use in a vehicle suspension and that can change damping force characteristics.

(Prior Art) As a conventional damping force variable hydraulic shock absorber, for example, one described in Japanese Utility Model Laid-Open No. 61-164836 is known.

In this conventional structure, as a means for generating a damping force at the time of extension, an orifice hole that connects the upper liquid chamber and the lower liquid chamber is formed in the piston, and a disc valve that opens and closes the orifice hole is provided. On the other hand, in the piston rod, a communication passage that connects the upper liquid chamber and the lower liquid chamber is formed in parallel with the orifice hole, and a variable orifice is provided in the middle of this communication passage. A check valve is provided in the middle of the communication passage to make the flow state of the hydraulic fluid different between the extension stroke and the pressure stroke.

According to this conventional pressure control valve, the two passages, the communication passage and the orifice hole, are arranged in parallel. Therefore, in the low piston velocity range, the damping of the velocity squared by the communication passage and the variable orifice is performed. The force characteristic is obtained, while in the medium and high piston velocity range, the disc valve opens and the damping force characteristic becomes 2/3 speed.

Further, when the flow passage cross-sectional area is changed by the variable orifice, the inclination of the damping force characteristic in the low piston velocity range changes, and the smaller the flow passage cross-sectional area, the higher the damping force characteristic.

(Problems to be solved by the invention) However, in such a conventional damping force variable hydraulic shock absorber, as described above, the communication passage is provided in parallel with the orifice hole of the piston, In the low piston speed range, the damping force is generated due to the characteristics mainly of the variable orifice and the communication passage, and in the middle and high piston speed range, the damping force is generated mainly due to the throttle generated in the disc valve.
There is a problem that the damping force characteristics of the low piston speed range and the middle and high piston speed range are different, and it is not possible to obtain a linear damping force characteristic in the entire speed range. Furthermore, when a hydraulic shock absorber whose characteristics change depending on the speed range is applied to the suspension of an automobile in this way, the characteristic changes of the suspension cannot be obtained constantly, and the ride comfort and steering stability are extremely poor. Was bad.

The present invention has been made in view of the above-mentioned problems of the prior art, and a damping force variable hydraulic buffer capable of obtaining a linear damping force characteristic with a substantially constant change rate in all speed ranges. The purpose is to provide a vessel.

(Means for Solving the Problems) In order to achieve the above-mentioned object, in the damping force variable type hydraulic shock absorber of the present invention, the inside is defined by the piston into the upper and lower liquid chambers, and the hydraulic fluid is filled therein. And an inner groove having a seat surface on each outer circumference, which is at least partially arcuately formed in an inner and outer double shape on the end surface of the piston on the liquid chamber side of at least one of the pistons, and An outer groove, a disc valve provided in contact with both seat surfaces to open and close both grooves, and a first communication passage that connects the inner groove and the other liquid chamber with the piston in between,
A second communication passage that is provided through the hollow portion of the piston rod to connect the outer groove and the other liquid chamber, and a portion that connects the hollow portion of the piston rod to the one liquid chamber. A check valve that allows only liquid inflow from the chamber, a first orifice portion that is rotatably arranged in the hollow portion of the piston rod, and adjusts the flow of the second communication passage, and a flow passage between the hollow portion of the piston rod and the check valve. The second orifice portion for adjusting the pressure is provided between the piston rod and the adjuster.

(Operation) In the variable damping force type hydraulic shock absorber of the present invention, when the piston strokes from one chamber side to the other chamber side, the operation in the other hydraulic chamber responds to the change in hydraulic pressure of the upper and lower liquid chambers. The liquid flows into the outer groove via two paths, and from this outer groove, the disc valve is bent and flows into one of the liquid chambers through the gap between the disc valve and the outer seat surface.

Therefore, although there are two paths from the other liquid chamber to the outer groove, the first path flows from the first communication passage into the inner groove,
A path from which the disc valve is bent and flows into the outer groove through a space between the inner valve seat inner peripheral surface of the inner groove and the disc valve. In this case, a damping force having a velocity 2/3 power characteristic is generated between the inner seat surface and the disc valve.

The second path is a path from the other liquid chamber to the outer groove via the second communication path penetrating the hollow portion of the piston rod. A first orifice portion of the adjuster is formed in the middle of the second communication passage, and when the hydraulic fluid flows through the first orifice portion, a damping force having a velocity squared characteristic is generated. At this time, the check valve restricts the working fluid from directly flowing from the hollow portion of the piston rod into the one fluid chamber.

In addition, when the hydraulic fluid that has flowed into the outer groove via one of the two paths flows into one of the fluid chambers by opening the disc valve, a damping force with a speed 2/3 power characteristic is generated. To do.

Therefore, when the piston speed is low, the hydraulic fluid flows into the outer groove without opening the inner seat surface and through the second communication passage and the first orifice part in the middle of which the flow is easier. To do. Therefore, the damping force of the velocity-squared characteristic of the first orifice portion, which increases with the increase in speed, and the increase rate with the increase in speed between the outer seat surface and the disc valve, decrease. Speed 2 /
Since the damping force of the third power characteristic is generated in series, it is possible to obtain a linear damping force characteristic.

Further, when the piston speed increases and the flow rate of the first orifice passes, the hydraulic fluid does not pass through the second communication passage but flows into the inner groove from the first communication passage, and from there, at the position of the inner seat surface. The disc valve is opened and flows into the outer groove. Therefore,
Inner seat surface speed 2/3 power characteristic and outer seat surface speed 2/3
The damping force of the riding characteristic is applied in series. Also in this case, the velocity 2/3 power characteristic that the damping force increase rate decreases independently with the increase of the piston speed is added in series to suppress the decrease of the damping force increase rate in the middle / high speed range. Therefore, a linear damping force characteristic can be obtained.

Therefore, it is possible to obtain a damping force characteristic that is linear with respect to the piston speed in both the low speed range and the medium / high speed range.

Further, when the flow rate of the first orifice portion is reduced, the damping force characteristic becomes a high damping force characteristic, and when the flow rate is increased, it becomes a low damping force characteristic. Also in this case, this linear characteristic is obtained in the entire range of variable damping force.

On the other hand, when the piston strokes to the side of the one liquid chamber, contrary to the above, the working fluid in the one liquid chamber opens the check valve and flows into the hollow portion of the piston rod, and from there, at the second orifice portion. After the flow is adjusted, it flows into the other liquid chamber. In this case, a damping force having a velocity squared characteristic is generated by the second orifice portion.

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

First, the configuration of the embodiment will be described.

FIG. 1 is a sectional view showing a main part of a damping force variable type hydraulic shock absorber according to a first embodiment of the present invention, in which 1 denotes a cylindrical cylinder. The cylinder 1 is divided into an upper liquid chamber A and a lower liquid chamber B by a piston 2 slidably mounted, and both chambers A and B are filled with a hydraulic fluid such as oil.

The piston 2 is attached to the tip of the piston rod 3, that is, with respect to the tip of the piston rod 3, a retainer 4, a washer 5, a pressure side disc valve 6, a piston 2, a first
Expansion side disk valve 7, second expansion side disk valve 8, washer 9, spring seat 10, spring 11 are installed in sequence,
Finally, it is attached by fastening with a nut 12.

More specifically, the piston 2 has a piston through hole 2a at the center for inserting the piston rod 3.

Further, on the upper end surface on the upper liquid chamber A side, a pressure side seat surface 2c is provided at the same height as the boss portion 2b, and the pressure side groove 2d is formed inside thereof.
The pressure side groove 2d is communicated with the lower liquid chamber B by the pressure side communication passage 21. The pressure side disc valve 6 is in contact with the boss portion 2b and the pressure side seat surface 2c.

2 is a plan view showing the upper surface of the piston 2. As shown in FIG. 2, the pressure side seat surface 2c and the pressure side groove 2d are provided at three places, and the pressure side groove 2d and the lower liquid chamber The pressure side communication passage 21 communicating with B is formed in a substantially quadrangular cross section.

Further, as shown in FIG. 1, the pressure side disc valve 6 is
And the upper surface of the piston 2 at a place other than the pressure side groove 2d, a gap is defined as a communication passage 2e.

On the other hand, an inner groove 2h and an outer groove 2j are formed on the lower end surface of the piston 2 on the lower liquid chamber B side so as to be double inside and outside. Both grooves 2
As shown in FIG. 3, which is a bottom view showing the bottom surface of the piston 2, h and j are formed in a substantially annular shape, and an inner seat surface 2m and an outer seat surface 2n are formed on the outer periphery thereof, respectively. The inner groove 2h is communicated with the upper liquid chamber A by six first extension side communication passages (first communication passages) 22 formed in the piston 2 in the vertical direction.

The outer groove 2j is communicated with the piston through hole 2a by communicating grooves 2p and 2q formed in the radial direction while avoiding the inner groove 2h.

As shown in FIG. 1, the two grooves 2h, 2j are the first expansion side disk valve 7 provided in contact with both seat surfaces 2m, 2n and the second expansion disk valve 7 contacted with the lower surface thereof. It is closed by the side valve disc 8. The outer circumference of the second extension side valve disc 8 is formed to have an outer diameter that matches the inner seat surface 2m, and the urging force of the spring 11 is applied to a position that matches the inner seat surface 2m. Therefore, the valve closing force for the inner groove 2h is high.

By the way, the piston rod 3 is formed with a piston rod hollow portion (hereinafter referred to as a hollow portion) 3a in the axial direction with its tip open to the lower liquid chamber B side. And this hollow part
3a is a piston rod 3 at a position matching the communication grooves 2p and 2q
The upper side ports 3b, 3b bored in the radial direction of the communication groove 2
The lower ports 3c, 3c formed at the lower end portion of the piston rod 3 communicate with p, 2q, and also communicate with the nut through hole 12a formed in the nut 12. That is,
The hollow portion 3a is communicated with the inner groove 2h and the outer groove 2j via the upper ports 3b, 3b and the two communication grooves 2p, 2q, and further from the inner groove 2h via the first extension side communication passage 22 to the upper portion. It is also connected to the liquid chamber A. The nut through hole 12a is formed in the lower liquid chamber B.
An opening is formed in the head of the nut 12.

That is, the inner groove 2h and the outer groove 2j formed on the lower surface of the piston 2 are the second extension side communication passage R (indicated by a one-dot chain line arrow) formed of the communication groove 2p, the upper ports 3b, 3b and the communication groove 2q. Show)
That is, the outer groove 2j is
The extension side communication passage R, the inner groove 2h, and the first extension side communication passage 22 communicate with the upper liquid chamber A, and these (R, 2h, 22) constitute the second communication passage in the claims. ing.

In the hollow portion 3a in the middle of the second extension side communication passage R,
The adjuster 15 is sandwiched between the thrust bush 16 and the plate 17, and is provided so as to be rotatable coaxially with the piston rod 3. This adjuster 15 is formed in a hollow cylindrical shape, and
Orifices 15a and 15b are bored so as to correspond to the upper port 3b of the piston rod 3, and orifices 15c and 15d are bored so as to correspond to the lower port 3c. That is, the orifices 15a and 15b constitute a first orifice portion in the scope of controlling the flow rate of the hydraulic fluid in the second extension side communication passage R, while the orifices 15c and 15d are It constitutes the second orifice portion in the range. The adjuster 15 is connected to an actuator (not shown) via a control rod 18, and each orifice 15 is driven based on the drive of the actuator.
It is possible to selectively match a to 15d with both ports 3b and 3c.

Further, the nut 12 is provided with a check valve 19. That is, the valve body 19a is fitted in the nut through hole 12a of the nut 12. A disc valve 19b is provided by a spring 19c so as to allow only the flow of the working fluid from the lower fluid chamber B to the hollow portion 3a and restrict the reverse flow to the valve body 19a. Has been.

The configuration of the main part of the first embodiment has been described above with reference to FIGS. 1 to 3, but in the lower portion of the cylinder of the present embodiment, which is not shown, a base that defines a reservoir chamber and a lower liquid chamber (not shown) is provided. In addition, the base has a speed during the pressure stroke.
A valve that generates a damping force with a 2/3 power characteristic is provided.

Next, the operation of the embodiment will be described.

(A) During Stroke During the stroke of the piston 2, the hydraulic fluid in the upper liquid chamber A flows into the lower liquid chamber B as the hydraulic pressure in the upper liquid chamber A increases.
The path of the hydraulic fluid at this time is as follows.

In the present embodiment, the hydraulic fluid in the upper liquid chamber A is the first extension side communication passage.
It flows into the outer groove 2j through 22 and then flows into the outer groove 2j by following one of two routes described later, and the first extension side disk valve 7 is bent from the outer groove 2j, It flows into the lower liquid chamber B through a space between the outer seat surface 2n and the first expansion side disc valve 7.

Therefore, there are two routes from the inner groove 2h to the outer groove 2j. First, the first route is the inner groove 2h.
Is a path through which the first and second expansion-side disk valves 7 and 8 are bent to flow into the outer groove 2j through a gap formed between the inner seat surface 2m and the first expansion-side disk valve 7. The other route is the inner groove 2h to the communication groove 2p to the upper port 3b.
After passing through the orifices 15a, 15b-upper port 3b-communication groove 2q,
That is, it is a path that flows into the outer groove 2j via the second extension side communication path R. That is, the hydraulic fluid circulates through one of these two paths, whichever has the least resistance.

By the circulation of the hydraulic fluid through the above path, a hydraulic pressure difference as shown in FIG. 4 is generated between the inner groove 2h and the outer groove 2j to generate a damping force, that is, , These two grooves
Between 2h and 2j, in the low piston speed range, the hydraulic fluid flows through the second extension side communication passage R with low resistance, and the damping force characteristics of the speed square are obtained, while in the middle / high piston speed range. Then, in response to the increase of the flow resistance in the orifices 15a, 15b, both the disc valves 7, 8 are opened at the position of the inner seat surface 2m to allow the flow in the route connecting the inner groove 2h and the outer groove 2j. Occurs, and the damping force characteristic becomes 2/3 speed.

On the other hand, between the outer groove 2j and the lower liquid chamber B, a hydraulic pressure difference as shown in FIG.
Due to the flow of opening the first expansion side disc valve 7 at the position of the outer seat surface 2n, the characteristic of the first expansion side disc valve 7 becomes the damping force characteristic of speed 2/3 power.

Therefore, in the entire hydraulic shock absorber of the embodiment, during the extension stroke,
A characteristic in which the characteristics shown in FIGS. 4 and 5 are added in series is obtained, and this characteristic is a characteristic close to a straight line as shown in FIG.

The damping force characteristics described above are obtained by rotating the adjuster 15 and
This can be changed by changing the orifices 15a and 15b provided in the middle of the extension side communication passage R. That is, fourth to
In FIG. 6, and, respectively, when the smallest diameter of the orifices is matched to have a high damping force characteristic, when the middle diameter is matched to have a medium damping force characteristic, and The case where the diameters are matched with each other to have a low damping force characteristic is shown.

(B) During pressure stroke During the pressure stroke of the piston 2, the hydraulic fluid in the lower liquid chamber B flows into the upper liquid chamber A in the piston 2 through two routes.

That is, as the first path, the check valve 19 is opened, and the lower ports 3c, 3c and the orifice of the adjuster 15 (second
Orifice part) 15c, 15d enters the adjuster 15, and from there, traces the second extension side communication passage R in reverse, that is, the orifice
15a-upper port 3b-communication groove 2p-inner groove 2h-first extension side communication passage 22 in order to flow into the upper liquid chamber A.

The other path is a path through which the pressure side disk valve 6 is opened from the pressure side communication passage 21 and flows into the upper liquid chamber A.

The hydraulic fluid flows through one of the two paths, which has the smaller flow resistance, and normally, when the piston speed is low, the check valve 19 is opened to reversely flow through the second extension side communication passage R. However, in this case, a damping force having a velocity squared characteristic is generated. Further, in the medium / high speed range, the pressure side disc valve 6 is opened to flow, and in this case, a damping force having a speed 2/3 power characteristic is generated.
Therefore, the damping force generated in the piston 2 during the pressure stroke has the same characteristics as shown in FIG. 4, but the generated damping force itself is set lower than that.

Further, during this pressure stroke, a damping force having a velocity 2/3 power characteristic is also generated in the base valve (not shown), and this damping force is shown by the dotted line in FIG.

Therefore, the characteristic in which the damping force generated in the piston 2 and the base not shown in the figure is combined becomes a characteristic close to a straight line as shown by and in FIG. It should be noted that the difference in the characteristics of-is caused by the selection of the orifices 15a-d of the adjuster 15.

As described above, in the damping force variable type hydraulic shock absorber according to the first embodiment of the present invention, the inner groove 2h and the upper fluid are doubled on the lower surface side of the piston 2 by providing the inner groove 2h and the outer groove 2j. The chamber A is communicated with the first extension side communication passage 22, and the inner groove 2h and the outer groove 2j are connected.
Are communicated with the second extension side communication passage R, and the orifices (first orifice portions) 15a, 15 of the adjuster 15 are provided in the middle of the second extension side communication passage R.
Since b is provided, the damping force of the velocity squared characteristic of the orifices 15a to 15d of the adjuster 15 and the velocity 2/3 squared characteristic of the first expansion side disk valve 7 are obtained in series in the low speed region. Since the speed 2/3 power characteristics are obtained in series in the high speed range, it is possible to obtain a linear damping force characteristic in the entire speed range.

Note that this characteristic is the same even when the orifices 15a, 15b that match the second extension side communication passage R are changed to change the throttle amount, so that this linear characteristic is obtained in the entire range of the damping force variable. The effect of being able to be obtained is obtained.

Furthermore, due to the effect that this linear characteristic is obtained, there is an effect that both riding comfort and steering stability can be achieved when the characteristic is not suddenly changed by the piston speed and applied to a suspension of an automobile. can get.

In addition, in this embodiment, both extension side disc valves 7 and 8 for generating a damping force during the extension stroke are provided on the lower surface side of the piston 2, and the compression side disc valve 6 for producing the damping force during the pressure stroke is provided. Since the valve is provided on the upper surface of the piston 2, that is, the valve is provided on one side of the piston 2, the disk valves 6,7,8 for the extension stroke and the pressure stroke, the inner and outer grooves 2h, 2j, and the first and second grooves. The two extension-side communication passages R can be easily provided on both sides of the piston 2 independently of each other, which has the effect of simplifying the configuration. At the same time, the extension stroke and the pressure stroke are independent. Thus, the damping force can be set, and the degree of freedom in setting the damping force is improved.

Next, the damping force variable hydraulic shock absorber of the second embodiment shown in FIG. 8 will be described. In the explanation of the shock absorber of the second embodiment, the same components as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The second embodiment differs from the first embodiment in the structure corresponding to the second communicating passage in the claims.

That is, the hollow portion 23a of the piston rod 23 of the second embodiment is
It is deeply formed upward to a position above the piston 2, and the hollow portion 23a and the upper liquid chamber A are communicated with each other by the upper port 23b. Then, the piston 20 is attached to the piston rod 23.
An intermediate port 23d is formed near the center of 2, and a lower port 23c is formed at the lower end. Further, an annular groove 23e is formed on the outer periphery of the position of the intermediate port 23d.

On the other hand, the adjuster 215 has a dimension longer than that of the first embodiment, and the orifices 215a and 215b are formed at the positions corresponding to the upper port 23b, and the orifices are formed at the positions corresponding to the intermediate port 23d. 215c and 215d are bored, and orifices 215e and 215f are bored at positions corresponding to the lower port 23c.

Further, as shown in FIG. 10 which is a bottom view showing the bottom surface of the piston 2 of the second embodiment, the communication grooves 2p and 2q of the first embodiment are not formed on the bottom surface of the piston 2 and The side groove 2h and the outer groove 2j are formed in a complete annular shape, and as shown in FIG. 8, one end of the piston 2 is opened to the outer groove 2j,
Piston through hole 2 at a position where the other end matches the annular groove 23e
A communication hole 24 is formed in the opening a.

Therefore, the outer groove 2j of the second embodiment is composed of the communication hole 24 and the annular groove 23.
e, intermediate port 23d, orifices 215c and 215d, and adjuster 215
Second extension-side communication passage (corresponding to the second communication passage in the claims), which is composed of the inside, orifices 215a, 215b, and upper port 23b
It is connected to the upper liquid chamber A by 2R.

In the second embodiment having the above-described structure, during the extension stroke, the hydraulic fluid flows through the second extension side communication passage 2R or from the first extension side communication passage 22 through the inner groove 2h. Disc valve 7,
The fluid flows into the outer groove 2j by following the path for opening the valve 8, from which the first extension side disc valve 7 is opened and flows into the lower liquid chamber B.

Therefore, in the low speed region, the damping force of the velocity squared characteristic is generated in the orifices 215a to 215d, and in the medium and high speed regions, the velocity 2/3 squared characteristic is damped between the inner seat surface 2m and the first expansion side disc valve 7. Power is generated. As a result, the same operation as in the first embodiment
The effect is obtained.

Further, in the second embodiment, during the pressure stroke, the working fluid in the lower liquid chamber B flows into the upper liquid chamber A through the pressure side communication passage 21 and the check valve 19 is opened to open the lower side. Port 23c
Also, there are parallel paths that enter the adjuster 215 through the orifices 215e and 215f and then flow into the upper liquid chamber A through the orifices 215a and 215b and the upper port 23b. As a result, the same action and effect as those of the first embodiment can be obtained.

Incidentally, FIG. 9 is a plan view showing the upper surface of the piston 2 of the second embodiment.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and the present invention can be applied even if there is a design change or the like within a range not departing from the gist of the present invention. included.

For example, in the embodiment, the invention is applied to the one that generates the damping force in the extension stroke, but it is naturally applicable to the one that generates the damping force in the pressure stroke, and further, the damping force is generated in both the extension and compression strokes. It may be used for any purpose.

(Effect of the Invention) As described above, in the damping force variable hydraulic shock absorber of the present invention, the inner groove and the outer groove are doubled on at least one liquid chamber side of the piston, and one of the inner grooves is formed. A first communication passage communicating with the other liquid chamber and a second communication passage communicating with the outer groove with the other liquid chamber, and a first orifice portion of the adjuster provided in the middle of the second communication passage. With this configuration, the damping force of the velocity square characteristic and the velocity 2/3 characteristic can be obtained in series in the low speed range, and the velocity 2/3 characteristic can be obtained in series in the middle / high speed range. An effect that a linear damping force characteristic can be obtained in the range is obtained.
Since this characteristic is the same even when the throttle amount of the first orifice portion is changed,
The effect of obtaining this linear characteristic is obtained.

Furthermore, due to the effect that this linear characteristic is obtained, there is an effect that both riding comfort and steering stability can be achieved when the characteristic is not suddenly changed by the piston speed and applied to a suspension of an automobile. can get.

In addition, in the shock absorber of the present invention, since the inner and outer grooves and the disc valve are provided on one side of the piston, the disc valve for the extension stroke and the pressure stroke, the inner and outer grooves and the communication passage are respectively provided on both sides of the piston. It can be easily provided independently, and thus the structure can be simplified. Moreover, since the flow paths of the hydraulic fluid are different between the extension stroke and the pressure stroke, the damping force can be set independently on the extension side and the pressure side, and the degree of freedom in setting can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an essential part of a damping force variable type hydraulic shock absorber according to a first embodiment of the present invention, FIG. 2 is a plan view showing a top surface of a piston of the embodiment, and FIG. 3 is a bottom view of the piston. The bottom view shown in FIG. 4, FIG. 4 is a graph showing the relationship between the hydraulic pressure difference between the inner groove and the outer side of the embodiment, and the piston speed, and FIG. 5 is the hydraulic pressure difference between the outer groove and the lower liquid chamber of the embodiment. 6 is a graph showing the relationship between the piston speed and the piston speed, FIG. 6 is a graph showing the relationship between the piston speed and the damping force generated during the extension stroke of the embodiment, and FIG. 7 is the damping force generated during the pressure stroke of the first embodiment. And FIG. 8 is a graph showing the relation between the piston speed and the piston speed. FIG. 8 is a sectional view showing the essential part of the damping force variable type hydraulic shock absorber of the second embodiment of the present invention. FIG. 10 is a plan view showing the bottom surface of the piston of the second embodiment. A …… Upper liquid chamber B …… Lower liquid chamber 1 …… Cylinder 2 …… Piston 2h …… Inner groove (part of the second communication passage) 2j …… Outer groove 2m …… Inner seat surface 2n …… Outer seat Surface 7 …… First expansion side disk valve 8 …… Second expansion side disk valve 15 …… Adjuster 15a …… Orifice (first orifice part) 15b …… Orifice (first orifice part) 15c …… Orifice (first 2 Orifice part) 15d Orifice (second orifice part) 19 ... Check valve 22 ... First extension side communication passage (a part of first communication passage and second communication passage) R ... Second extension side communication Passage (Second communication passage) 2R …… Second expansion side communication passage (Second communication passage) 215 …… Adjuster 215a …… Orifice (First and second orifices) 215b …… Orifice (First and second orifices) ) 215c …… Orifice (first orifice part) 215d …… Orifice (first orifice part) 215e …… Orifice (second orifice part) 215f …… Orifice (second orifice part)

Claims (1)

[Scope of utility model registration request] 1. A cylinder, which is internally defined by a piston into upper and lower liquid chambers and is filled with hydraulic fluid, is provided on at least one liquid chamber side of the piston, and at least partially on an end face of the piston. An inner groove and an outer groove which are arcuately formed in double and have a seat surface on each outer circumference; a disc valve provided in abutting state on both seat surfaces to open and close both grooves; and the inner groove. A first communication passage that communicates with the other liquid chamber with the piston in between, and a second communication passage that penetrates through the hollow portion of the piston rod to communicate the outer groove with the other liquid chamber; A check valve provided in a portion for communicating the rod hollow portion with one of the liquid chambers and allowing only liquid inflow from the one liquid chamber; and a check valve rotatably arranged in the piston rod hollow portion.
A regulator for forming a first orifice portion for controlling the flow of the communication passage and a second orifice portion for controlling the flow of the hollow portion of the piston rod and the check valve between each piston rod; Variable damping force type hydraulic shock absorber.