JPH0735766Y2 - Suspension device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a suspension device which is mounted between an axle of a vehicle or the like and a vehicle body to efficiently reduce vertical vibration and rolling vibration of the vehicle body caused by unevenness of a road surface. Is.

2. Description of the Related Art A general vehicle is equipped with a hydraulic shock absorber between the axle and the vehicle body to enhance the riding comfort of the vehicle. However, if the damping characteristic of this shock absorber is too small, This causes a shake of the vehicle body, that is, an increase in rolling angle, which causes problems in the riding comfort and high-speed safety.

Regarding the above, for example, Japanese Utility Model Publication No. 16-18188 and Japanese Utility Model Publication No. 47188
-29914 discloses the configuration of the suspension device shown in FIG. Since the hydraulic buffer (I) and the hydraulic buffer (II) in the figure have exactly the same structure,
For convenience, the structure of the hydraulic shock absorber (I) will be described.
Reference numeral 1 is an outer cylinder, 2 is an inner cylinder, and the outer cylinder 1 and the inner cylinder 2 form a pressure cylinder 90. A liquid storage chamber C is formed between the outer cylinder 1 and the inner cylinder 2. 3 is an upper lid, 4 is a lower lid, 5
Is a piston, and the piston 5 is slidably inserted and arranged along the inner wall surface of the inner cylinder 2 to divide the inside of the inner cylinder 2 into an upper pressure chamber A and a lower pressure chamber B. A piston rod 6 fixed to the piston 5 penetrates the upper lid 3 under liquid-tight sealing and projects to the outside. Reference numerals 7 and 8 are connection paths provided in the upper lid 3 and the lower lid 4 so as to communicate with the upper pressure chamber A and the lower pressure chamber B from the outside, and 9 and 10 are pistons so that the upper pressure chamber A and the lower pressure chamber B are communicated with each other. 5 is a liquid passage, and in this liquid passage 9, a pressure regulating valve 11 which allows only the flow of the working fluid from the upper pressure chamber A to the lower pressure chamber B is provided,
In the other liquid passage 10, there is provided a pressure regulating valve 12 which allows only the working fluid to flow from the lower pressure chamber B to the upper pressure chamber A. 13 is an orifice provided in the inner cylinder 2 for connecting the upper pressure chamber A and the liquid storage chamber C, and 14 is provided in the lower lid 4 for connecting the lower pressure chamber B and the liquid storage chamber C A check valve 15 is provided inside the connection passage 14, which only allows the working fluid to flow from the liquid reservoir chamber C to the lower pressure chamber B. Reference numerals 16 and 17 denote attachment rings to the vehicle, which are fixed to the outer protruding end of the piston rod 6 and the lower lid 4.

In the hydraulic shock absorber (II), the same components are indicated by the same reference numerals and dashes (').

The upper pressure chamber A of the hydraulic shock absorber (I) configured as described above
And the lower pressure chamber B'of the hydraulic shock absorber (II) on the other side are connected via the connecting portion 7, the valve body 22, the pipe 18, the valve body 25 and the connecting passage 8 ', and the hydraulic pressure is The upper pressure chamber A'of the shock absorber (II) and the lower pressure chamber B of the hydraulic shock absorber (I) are connected to each other by a connecting passage 7 ', a valve body.
28, the pipe 19, the valve body 31, and the connection path 8 are connected. It should be noted that the valve body 22 has an upper pressure chamber A through a lower pressure chamber B '.
A pressure regulating valve 20 that allows only the flow of hydraulic fluid to and a check valve 21 that blocks only the flow in that direction are built in, and other valve bodies 25, 28, 31
Also has pressure regulating valves 23, 26, 29 and check valves 24, 2 having similar functions.
7,30 are built-in.

According to such a configuration, when the hydraulic shock absorbers (I) and (II) both expand due to the vertical vibration while the vehicle is traveling, the pistons 5, 5'move above the inner cylinders 2, 2'and the upper part Pressure chamber A,
The hydraulic fluid in A'is pressurized, and a part of this hydraulic fluid passes through the pressure regulating valves 11, 11 'provided in the fluid paths 9, 10' of the pistons 5, 5 ', and the upper pressure chamber A, At the same time when the fluid flows from A'to the lower pressure chambers B and B ', another part of the hydraulic fluid flows from the connecting passages 7 and 7'to the valve bodies 22 and 2.
8, through the pipes 18 and 19, the valve bodies 25 and 31, and the connecting passages 8'and 8, they flow out to the lower pressure chambers B'and B on the other side. The flow resistance of the hydraulic fluid at this time acts as a damping force, and the vibration energy of the vehicle is absorbed. In addition, each lower pressure chamber B,
In B ', the amount of hydraulic fluid corresponding to the withdrawal volume of the piston rods 6, 6'is insufficient, but the hydraulic fluid in the liquid reservoir chambers C, C'from this connecting valve 14, 14' is a check valve. 15,15 'are opened and flow in, and this is replenished.

Conversely, when the hydraulic shock absorbers (I) and (II) are both compressed, the pistons 5 and 5'move downward in the inner cylinders 2 and 2 ', and the lower pressure chamber
The hydraulic fluid in B, B'is pressurized, and a part of this hydraulic fluid is provided in the liquid passages 10, 9'of the pistons 5, 5 ', and pressure regulating valves 12, 12' are provided.
Through the lower pressure chambers B and B'to the upper pressure chambers A and A ', and at the same time, another part of the hydraulic fluid flows from the connecting passages 8 and 8'to the pipe 1
Outflow into the upper pressure chambers A ′, A of the hydraulic shock absorbers on the other side via the pressure regulating valves 29, 23, check valves 27, 21 and connecting paths 7 ′, 7 provided in the middle of 9, 18 respectively. To do. At this time, the flow resistance of the hydraulic fluid acts as a damping force, and the action that the downward kinetic energy of the pistons 5 and 5'is absorbed is obtained.

In addition, since the total volume of the pressure chamber is reduced by the volume of the piston rods 6 and 6 ′ that penetrates into the upper pressure chambers A ′ and A during the above operation, a part of the surplus hydraulic fluid is partially removed from the orifice 13, 1
It flows into the liquid storage chambers C, C'from 3 '.

Furthermore, as when rolling the vehicle body, the hydraulic shock absorber (I) (I
I) Consider the operation mode in which one expands and the other compresses. If the hydraulic shock absorber (I) is located outside when the vehicle turns, the hydraulic shock absorber (I) is compressed and the lower pressure chamber B becomes high pressure, and a part of the hydraulic fluid is As described above, it is about to move to the upper pressure chamber A'of the hydraulic shock absorber (II) on the other side. However, at this time, the hydraulic shock absorber (II) located on the inner side in the turning direction is trying to expand conversely, and the upper pressure chamber A'has a high pressure.

For this reason, the flow of hydraulic fluid between the two hydraulic buffers (I) and (II) is blocked from each other, and each hydraulic buffer (I) (II) is connected from the lower pressure chamber B to the upper pressure chamber A, and Only the hydraulic fluid is allowed to flow from the lower pressure chamber B'to the upper pressure chamber A ', the flow resistance increases, the damping force increases, and the damping property during rolling is improved. There is.

However, in the structure of such a conventional suspension device, in order to connect a pair of hydraulic shock absorbers (I) and (II), two pipes 18, 19 and four pipes are provided. Since the valve bodies 22, 25, 28, 31 of the above are required at a minimum, there is a problem that the entire structure becomes complicated. Furthermore, the above hydraulic buffer (I) (I
If an abnormality occurs in any one of I), the pipe, and each valve body, the function as the suspension device is impaired.

Therefore, the present invention solves the problems of such a conventional suspension device, simplifies the overall structure, and responds to the operation of the hydraulic shock absorber on one side to the liquid on the other side. It is an object of the present invention to provide a hydraulic shock absorber that does not impair the function of the hydraulic shock absorber even when an abnormality occurs in piping and other members by operating the pressure shock absorber. is there.

Means for Solving the Problems In order to achieve the above object, the present invention provides a suspension device composed of a hydraulic shock absorber between each axle of a vehicle and a vehicle body for each wheel, as well as vertical vibration and rolling vibration of the vehicle body. According to the above, each of the hydraulic buffers is configured in a suspension device in which a pair of hydraulic buffers at front, rear, left and right, or diagonal positions of each wheel are linked by a transmission passage to adjust the damping force. A displacement flow of the working fluid between the upper and lower liquid chambers due to the vertical movement of the piston, which is slidably fitted into the pressure cylinder and defines an upper liquid chamber and a lower liquid chamber. Is provided to generate a damping force, the bypass passage of the pressure regulating valve is provided between the upper and lower liquid chambers, and the piston rod having the piston at one end is provided with a central hole penetrating in the axial direction. Form the central hole A spool is slidably arranged therein, and the inside of the center hole is vertically divided to form a lower pressure chamber of a lower fluid chamber of the hydraulic buffer, and an upper portion of the transmission passage as a pilot pressure chamber. Through the pilot pressure chamber of the other hydraulic buffer, and when only one hydraulic buffer is in the compression process, the spool is moved upward by the hydraulic pressure of the pressure receiving chamber and the other hydraulic buffer The spool device is configured so that the spool is moved downward, and a variable orifice that changes in the closing direction by the downward movement of the spool is provided in the bypass passage.

According to the configuration of the suspension device, the displacement flow of the hydraulic fluid between the upper and lower liquid chambers is generated by the pressure regulating valve along with the vertical movement of the piston in the pressure cylinder during the vibration of the vehicle, and a desired damping force is generated. However, when only one hydraulic shock absorber is in the compression process, the lower hydraulic pressure of the hydraulic shock absorber is increased,
This hydraulic pressure is transmitted from the pressure receiving chamber of the hydraulic buffer to the spool slidably arranged in the center hole formed penetrating in the axial direction of the piston rod, and the spool moves upward. The bypass passage of the pressure regulator valve of the hydraulic buffer remains open.

At the same time, the hydraulic pressure in the pilot pressure chamber is increased in association with the upward movement of the spool, and the hydraulic pressure is transmitted from this pilot pressure chamber to the pilot pressure chamber of another hydraulic buffer via the transmission passage, whereby other hydraulic pressure is transmitted. Since the spool of the hydraulic shock absorber moves downward, the downward movement of the spool changes the variable orifice in the spool in the closing direction to narrow the bypass passage, thereby increasing the damping force of the hydraulic shock absorber.

Embodiment An embodiment of the suspension device according to the present invention will be described below in detail by giving the same reference numerals to the same components as those of the conventional configuration.

In the configuration shown in FIG. 1, the hydraulic buffer (I) in the figure
And (II) are hydraulic shock absorbers that are arranged between the axles of each wheel of the vehicle and the vehicle body to dampen the vertical vibration of the vehicle body. It is a hydraulic shock absorber that adjusts the damping force by interlocking a pair of hydraulic shock absorbers at front, rear, left and right, or diagonal positions of each wheel according to vibration and rolling vibration through a transmission passage. For the sake of convenience, the hydraulic shock absorber (I) will be described because it has exactly the same configuration.
Reference numeral 2 denotes an inner cylinder, and the outer cylinder 1 and the inner cylinder 2 make the pressure cylinder 90
Is formed. A liquid storage chamber C is formed between the outer cylinder 1 and the inner cylinder 2. Reference numeral 3 is an upper lid, 4 is a lower lid, and 5 is a piston. The piston 5 includes a stud 5b fixed to a lower end of a piston rod 6 by a support 55, and the stud 5b.
And a piston valve 5a fixed to the outer peripheral portion near the lower end of the inner cylinder 2 and slidably contacting the inner surface of the inner cylinder 2. Therefore, the inside of the inner cylinder 2 is divided into an upper pressure chamber A and a lower pressure chamber B by the piston 5. Well defined. This piston valve 5a has an upper pressure chamber A
Pressure regulating valve 11 which allows the displacement flow of the working fluid from the lower pressure chamber B to the lower pressure chamber B and the damping flow which allows the displacement flow of the working fluid from the lower pressure chamber B to the upper pressure chamber A to generate the damping force A pressure regulating valve 12 is provided.

The upper end of the piston rod 6 penetrates the upper lid 3 in a liquid-tight seal and is attached to the vehicle body, and a central hole 35 penetrating in the axial direction is formed, and the central hole 35 is enlarged and shown in FIG. As described above, a large diameter is formed on the mounting end side of the stud 5b to form a receiving hole 35a. A spool 60 including a first spool 62 and a second spool 63 is fitted into the receiving hole 35a. Is the first spool
The O-ring 75, which is slidable in the accommodating hole 35a and wound around the outer periphery thereof, divides the accommodating hole 35a into a first pilot pressure chamber 81 on the central hole 35 side and a chamber on the stud 5b side. The second spool 63 is slidably fitted into the recess 62a formed facing the chamber, and the inside of the recess 62a is surrounded by the O-ring 76 wound around the outer periphery of the second spool 63. The upper second pilot pressure chamber 82 and the lower pressure receiving chamber 83 are separated from each other.

A pressure guide passage 72 is provided in the bottom wall of the first spool 62, and the pressure guide passage 72 is preferably the second spool 63.
It is better to hold the diaphragm with an appropriate diameter so that it does not move suddenly. The pressure guiding passage 72 connects the first pilot pressure chamber 81 and the second pilot pressure chamber 82 to form a pilot pressure chamber 80.

Further, the first spool 62 is urged downward by a spring 65 that is compressed between the first spool 62 and the bottom wall 6c of the accommodation hole 35a, and the lower end portion is always in contact with the shoulder portion 5c of the piston 5 and the upper end portion The portion has a predetermined gap with the stepped portion 6b in the accommodation hole 35a, and this gap is the movable range of the first spool 62.

Further, the pressure receiving chamber 83 is formed as a concave portion of the second spool 63, and the second spool 63 is biased upward by a spring 66 that is contracted between the bottom wall of the concave portion and the stud 5b. The first spool 62 is always in contact with the stepped portion 62b in the recess 62a, and at this time, a gap is formed between the lower end of the second spool 63 and the upper end of the stud 5b. It becomes the movable range of the second spool 63 and serves as a variable orifice 68 of a bypass passage, which will be described later.
The set load of the spring 65 is set to be larger than the set load of the spring 66.

A communication passage 61 is formed in the stud 5b so as to penetrate in the axial direction, and the communication passage 61 allows the lower pressure chamber B and the pressure receiving chamber B to be communicated with each other.
The first and second passages 7 communicating with 83 and penetrating inward and outward through the side wall of the first spool 62 and the piston rod 6.
0,71 are formed respectively, and thus the lower pressure chamber B is connected to the communication passage.
61, pressure receiving chamber 83, variable orifice 68, first passage 70, second
Bypass passage X leading to upper pressure chamber A via passage 71 of
Is configured. The variable orifice 68 is configured to open when the spool 60 moves upward and to gradually narrow when the spool 60 moves downward.

Reference numeral 73 denotes an escape hole formed between the second spool 63 and the upper end of the stud 5b. When the first spool 62 moves downward, the hydraulic fluid passes through the escape hole 73 and the communication passage 61 side. To move to. As shown in FIG. 1, the hydraulic shock absorber (II) paired with the hydraulic shock absorber (I) has the same reference numerals and dashes (') attached to the same components. It is displayed.

The central hole 35 of the hydraulic shock absorber (I) is provided between the hydraulic shock absorbers of a pair of wheels in the front-rear, left-right or diagonal positions via the transmission passage 49, the reservoir tank main body 50 and the pipe 49 '. The suspension device according to this embodiment is constructed by connecting to the central hole 35 'of the hydraulic shock absorber (II) on the side.

According to this configuration, when the vertical vibration of the vehicle body due to the unevenness of the road surface when the vehicle is traveling occurs, the hydraulic shock absorber (I)
When both (II) are extended and the hydraulic buffer (I) (I
The operation mode when I) is compressed together is the same as the operation mode of a conventional hydraulic shock absorber known from the past,
Pressure regulating valves 11 and 12 and pressure regulating valve 1 of each hydraulic buffer (I) (II)
The basic action of absorbing the vibration energy of the vehicle by obtaining the damping force due to the flow resistance of the hydraulic fluid passing through 1'and 12 'is the same, so a detailed explanation of the operation in such a case will be omitted and the following will be explained. The following is a description of the operation when the vehicle body rolls during turning, the hydraulic shock absorber (I) is compressed as shown in FIG. 3, and the hydraulic shock absorber (II) is extended.

That is, when the hydraulic shock absorber (I) is located outside during turning of the vehicle, the hydraulic shock absorber (I) is compressed to increase the hydraulic pressure in the lower pressure chamber B, and Part of the hydraulic fluid flows from the lower pressure chamber B to the upper pressure chamber A via the pressure regulating valve 12 provided in the piston 5, and at the same time, another part of the hydraulic fluid is placed in the accommodation hole 35a. Flows into the pressure receiving chamber 83 inside. Then, this hydraulic pressure pushes the first spool 62 and the second spool 63 forming the spool 60 to the upper limit against the load of the spring 65 in the accommodation hole 35a.

With the upward movement of the spool 60, the first pilot pressure chamber 81
The hydraulic pressure of the pilot pressure chamber 80 constituted by the second pilot pressure chamber 82 and the second pilot pressure chamber 82 is increased, and this hydraulic pressure is arranged from the central hole 35 formed in the piston rod 6 to the vicinity of the upper end portion of the central hole 35. A similar annular groove formed in the hydraulic shock absorber (II) from the reservoir tank main body 50 and the pipe 49 ′ through the communication passage 47 (see FIG. 1) and the annular groove 46.
A pilot pressure chamber 80 consisting of a first pilot pressure chamber 81 'and a second pilot pressure chamber 82' which are also formed in the hydraulic shock absorber (II) through 46 ', the communication passage 47' and the central hole 35 '. ′
Be transmitted to.

Since the hydraulic shock absorber (II) is located inside when the vehicle is turning, the hydraulic shock absorber (II) is in a state in which the hydraulic shock absorber (II) is trying to expand, and the hydraulic pressure of the pilot pressure chamber 80 causes the accommodation hole in the hydraulic shock absorber (II). First spool 62 'and second spool 6 within 35a'
The spool 60 'composed of 3'is pushed down, and the second
The lower end of the spool 63 'moves downward until it contacts the stud 5b' against the load of the spring 66 '.

Along with this, the variable orifice 68 'in the hydraulic shock absorber (II) changes in the closing direction to move from the lower pressure chamber B'to the communication passage 61', the pressure receiving chamber 83 ', the variable orifice 68', and the first passage. The bypass passage consisting of 70 'and the second passage 71' is closed and the damping force of the hydraulic shock absorber (II) changes hard.

When the hydraulic pressure of the pilot pressure chamber 80 of the hydraulic buffer (I) is transmitted to the pilot pressure chamber 80 'of the hydraulic buffer (II), the first spool of the hydraulic buffer (II) is The second spool is formed by the throttling action of the pressure guiding passage 72 'provided on the bottom wall of the 62'.
It is possible to obtain an operation mode in which 63 'does not suddenly move down and the damping force does not change rapidly.

Summarizing the above operation, when only one hydraulic shock absorber (I) is in the compression process during rolling of the vehicle, the hydraulic pressure in the lower pressure chamber B of the hydraulic shock absorber (I) is increased, This hydraulic pressure is transmitted from the pressure receiving chamber 83 of the hydraulic shock absorber (I) to a spool 60 slidably arranged in a center hole 35 formed by penetrating in the axial direction of the piston rod 6, and this spool 60
Moves upward to open the bypass passage X of the pressure regulating valve 12 of the hydraulic buffer (I), and at the same time, the hydraulic pressure in the pilot pressure chamber 80 is increased with the upward movement of the spool 60, and this hydraulic pressure is increased. Central hole 35
And the spool 60 'of the hydraulic shock absorber (II) is moved downward by being transmitted to the pilot pressure chamber 80' of the hydraulic shock absorber (II) via another transmission passage, and by the downward movement of this spool 60 '. The variable orifice 68 'changes in the closing direction and the bypass passage is throttled, and the damping force of the hydraulic shock absorber (II) becomes large.

Therefore, as when rolling the vehicle, the hydraulic shock absorber (I) located outside in the turning direction is compressed and the hydraulic shock absorber (II) located inside in the turning direction expands. Even if there is, the expansion of the hydraulic buffer (II) is suppressed along with the compression of the hydraulic buffer (I), and the rolling phenomenon of the vehicle can be suppressed. Also, the same effect is exerted when the vehicle vibrates back and forth due to braking.

In the above description of the operation, when both the left and right wheels of the automobile ride on the convex portion of the road surface at the same time and the hydraulic shock absorbers (I) and (II) are compressed together, a high pressure is generated in the pipe 49. However, this high pressure is absorbed by the relief valve 53 of the reservoir tank body 50.

On the contrary, when the hydraulic buffers (I) and (II) are both extended, the working fluid is supplied from the reservoir tank 51 to the pipe 49 via the check valve 52, and the working fluid in the circuit is insufficient. Works like not.

Further, if the first spool 62 'and the second spool 63' move abruptly when the hydraulic shock absorber (II) returns from the extended state to the original state, abnormal noise is generated and the valve is worn. Therefore, the amount of liquid flowing from the pilot pressure chamber 80 can be adjusted by the third passage 72, and the return speed of each spool 62 ', 63' can be appropriately maintained.

Furthermore, since the working fluid in the lower pressure chamber B and the piping system connected to the fluid passage 35 are kept in a sealed state by the sealing members 75 and 76 provided in the variable valve 33, the working fluid and the piping It will not be mixed with the system oil,
Moreover, even when the hydraulic buffers (I) and (II) are frequently moved, the balance of the hydraulic fluids in both hydraulic buffers (I) and (II) is not disturbed, and the operation is prevented. The effect of being stabilized is obtained.

Effects of the Invention As described in detail above, the suspension device according to the present invention has the following effects. That is, during normal vehicle vibration, damping force is generated by the displacement flow of the hydraulic fluid between the upper and lower fluid chambers by the pressure regulating valve accompanying the vertical movement of the piston, while only one hydraulic shock absorber is in the compression process. Is transmitted from the pressure receiving chamber to the spool forming the variable valve in response to the increase in the lower liquid pressure of the liquid chamber shock absorber, and the upward movement of this spool opens the bypass passage of the pressure regulating valve to open the lower liquid. Fluid flows from the chamber to the upper fluid chamber to damp vibrations, and at the same time, the hydraulic pressure in the pilot pressure chamber increases with the upward movement of the spool, and other hydraulic pressure buffers from this pilot pressure chamber through the transmission passage. The hydraulic pressure is transmitted to the pilot pressure chamber of the device to move the spool of the hydraulic shock absorber downward, the variable orifice in the spool is changed to the closing direction and the bypass passage is closed, and the damping force of the hydraulic shock absorber is reduced. To reduce It is possible.

In particular, the hydraulic shock absorber of the present invention is incorporated in a suspension device independently provided on each wheel of a vehicle, and a single transmission pipe connecting each pair of hydraulic shock absorbers is sufficient. The effect is that structural simplification is achieved.

Further, in the case of the present invention, there is an advantage that the structure is simplified because the number of pipes connecting both hydraulic shock absorbers is one and a large number of valve bodies are not required unlike the conventional case.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an essential part showing an embodiment of a hydraulic shock absorber according to the present invention, FIG. 2 is a partial cross-sectional view showing a specific example of a pressure sensitive valve adopted in the present invention, and FIG. FIG. 4 is a partial cross-sectional view showing an example of the operation of the invention, and FIG. 4 is a cross-sectional view of essential parts showing an example of a conventional similar hydraulic shock absorber. 1 ... Outer cylinder, 2 ... Inner cylinder, 5 ... Piston, 6 ... Piston rod, 11,12 ... Pressure regulating valve, 35 ... Center hole, 37, 39 ...
… Check valve, 42 …… Vehicle side member, 49 …… Piping, 50 …… Reservoir tank body, 51 …… Reservoir tank, 52 …… Check valve, 53 …… Relief valve, 61
...... Communication passage, 62 …… First spool, 63 …… Second spool, 65,66 …… Spring, 68 …… Variable orifice, 7
5,76 …… O-ring, 80 …… Pilot pressure chamber, 81 …… Pressure receiving chamber, 90 …… Pressure cylinder.

Claims (1)

[Scope of utility model registration request] 1. A suspension device composed of a hydraulic shock absorber is provided for each wheel between an axle of a vehicle and a vehicle body, and front and rear, left and right, or diagonal of each wheel is adjusted according to vertical vibration and rolling vibration of the vehicle body. In a suspension device in which a pair of hydraulic shock absorbers at positions are interlocked with each other by a transmission passage to adjust the damping force, in the pressure cylinders forming each of the hydraulic pressure shock absorbers, the inside of the pressure cylinder is defined as an upper liquid chamber. A piston defining a lower liquid chamber is slidably inserted, and the piston is provided with a pressure regulating valve that allows a displacement flow of the working fluid between the upper and lower liquid chambers due to the vertical movement thereof to generate a damping force, A bypass passage of the pressure regulating valve is provided between the upper and lower liquid chambers, and a piston rod having the piston at one end is formed with a central hole penetrating in the axial direction, and a spool is slidably slidable in the central hole. And place it up and down in the center hole The lower part of the hydraulic buffer is divided into the pressure receiving chamber of the lower hydraulic chamber and the upper part of the hydraulic buffer communicates with the pilot pressure chamber of another hydraulic buffer via the transmission passage as a pilot pressure chamber. When only the hydraulic shock absorber is in the compression process, the spool is moved up by the hydraulic pressure of the pressure receiving chamber, the spools of other hydraulic shock absorbers are moved down, and the downward movement of this spool changes the closing direction. A suspension device characterized in that a variable orifice is provided in the bypass passage.