JP2005180689A - Hydraulic damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and low-cost hydraulic damper for solving problems, wherein the size of the hydraulic damper is increased and costs for manufacturing, adjustment or the like are required. <P>SOLUTION: A piston 7 is movably provided in a cylindrical cylinder 3. Piston rods 5-1, 5-2 are provided at both the sides of the piston 7. A first pressure chamber 9 and a second pressure chamber 11 in which a hydraulic fluid is filled into the cylinder 3 by the piston 7 are formed. Pressure regulating sections (a hydraulic valve 15, an elastic body 17, and a chamber 19 at the rear of the hydraulic valve) are provided between a channel 13-1 and a channel 13-2 for connecting the first and second pressure chambers 9, 11. When the pressure of the first pressure chamber 9 is high, hydraulic fluid flows from the channel 13-1 to the channel 13-2 when the hydraulic valve 15 is opened. When the pressure of the second pressure chamber 11 is high, hydraulic fluid flows from the channel 13-2 to the channel 13-1 when the hydraulic valve 15 is opened. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hydraulic damper used for a building or the like.

  Conventionally, hydraulic dampers have been used to reduce the shaking of buildings due to earthquakes and winds. The hydraulic damper uses the fluid resistance of oil to generate a resistance force (damping force) against the shaking of the building, absorbs the shaking of the building, and improves earthquake resistance and comfort.

  That is, the hydraulic oil filled in the cylinder of the hydraulic damper generates a damping force by the fluid resistance when passing through the hydraulic valve and absorbs the shaking of the building. Conventional hydraulic dampers are equipped with two pressure regulating valves so that a damping force is generated regardless of which direction the piston in the cylinder moves.

  The piston divides a cylinder filled with hydraulic oil into two pressure chambers. The hydraulic damper includes two pressure regulating valves. When the piston moves in the direction of compressing the first pressure chamber, the hydraulic oil passes through the first pressure regulating valve, thereby generating a damping force and absorbing vibration. Conversely, when the piston moves in the direction of compressing the second pressure chamber (ie, extending the first pressure chamber), the hydraulic oil passes through the second pressure regulating valve, thereby generating a damping force and generating vibration. Absorb. For example, there exists patent document 1 of the high damping device for earthquake-resistant structures. There is also an oil damper (Patent Document 2) that is also equipped with two pressure regulating valves and generates a required damping force even when the moving speed of the piston is in a low speed range.

In addition, there is a device that exhibits a damping performance even if the piston rod moves in any direction by combining one pressure regulating valve and four check valves.
Japanese Patent No. 2528563 JP-A-11-257405

  In the conventional method using two pressure regulating valves, it is necessary to adjust each of the two pressure regulating valves so as to exhibit a predetermined damping performance, which takes time.

  In addition, the use of two pressure regulating valves increases the manufacturing cost. Further, when the two pressure regulating valves are accommodated in the piston, a sufficient capacity for accommodating other valves and the like in the piston may be insufficient. That is, there are cases where the size of the piston is increased and the overall size of the apparatus is increased accordingly.

  As a method for solving this problem, there is a device that combines one pressure regulating valve and a plurality of check valves into one pressure regulating valve, but there is room for further miniaturization and cost reduction.

  The problem to be solved by the present invention is that the hydraulic damper is increased in size and costs such as manufacturing cost and adjustment are required.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a small-sized and low-cost hydraulic damper.

  The present invention for achieving the above-described object includes a cylinder filled with hydraulic oil, a piston that moves in the cylinder and divides the inside of the cylinder into a first pressure chamber and a second pressure chamber, In a hydraulic damper having piston rods provided on both sides or one side, and a flow path communicating with the first pressure chamber and the second pressure chamber, one hydraulic valve in the flow path, and the hydraulic valve And at least one pressure adjusting portion comprising an elastic body that supports a damping force generated in each of the two directions when the piston moves on the operating shaft in both directions at the same speed. The hydraulic damper is characterized by being substantially the same.

A structure for adjusting the magnitude of the fluid force acting on the hydraulic valve is provided in the hydraulic valve of the hydraulic damper.
The hydraulic valve of the hydraulic damper may be provided with a protruding structure and / or a stepped structure that adjusts the fluid force.
Here, the fluid force is a force exerted on the hydraulic valve by hydraulic oil (fluid) passing through the flow path.

A chamber is provided behind the hydraulic valve of the hydraulic damper, and a flow path for discharging the fluid in the chamber is provided.
The fluid in the room behind the hydraulic valve is discharged to another flow path when the hydraulic valve moves and pressure is applied. Conversely, when the pressure of the fluid in the chamber behind the hydraulic valve decreases, the fluid flows from the outside through the flow path.

In addition, small-diameter holes are provided in the hydraulic valve between the flow path communicating with the first pressure chamber and the chamber behind the hydraulic valve and between the flow path communicating with the second pressure chamber and the chamber behind the hydraulic valve. May be.
By providing a small-diameter hole in the hydraulic valve, an external fixed throttle for communicating with the accumulator that absorbs the volume expansion of the hydraulic oil becomes unnecessary. The volume-expanded hydraulic oil passes through the small diameter hole of the hydraulic valve, flows into the chamber behind the hydraulic valve, and is absorbed by flowing into the accumulator.

In addition, a small-diameter hole and a check between the flow path communicating with the first pressure chamber and the chamber behind the hydraulic valve in the hydraulic valve and between the flow path communicating with the second pressure chamber and the chamber behind the hydraulic valve, respectively. You may provide a valve in parallel.
By providing the hydraulic valve with a small-diameter hole and a check valve, a flow path for discharging the fluid in the chamber behind the hydraulic valve or allowing the fluid to flow in becomes unnecessary. Inflow and discharge of the fluid into the chamber behind the hydraulic valve are performed by a small-diameter hole and a check valve of the hydraulic valve.

The flow path of the hydraulic damper and the pressure adjusting unit may be accommodated in the piston. Further reduction in size can be achieved by housing the flow path and the pressure adjusting unit in the piston.
The pressure adjusting unit includes one hydraulic valve and an elastic body that supports the hydraulic valve. A pressure regulating valve, a relief valve, and other valves having a pressure regulating action are used for the pressure regulating unit.

  The hydraulic damper according to the present invention is provided with a pressure regulating unit including a hydraulic valve and an elastic body that supports the hydraulic valve in a flow path that connects the first pressure chamber and the second pressure chamber. The pressure adjusting unit makes the damping force generated in each of both directions substantially the same when the piston moves on the operating shaft in both directions at the same speed.

  ADVANTAGE OF THE INVENTION According to this invention, a small and low-cost hydraulic damper can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration of a hydraulic damper 1 according to the present embodiment.

(1. Configuration)
(1-1. Configuration of hydraulic damper 1)
The hydraulic damper 1 in FIG. 1 has a piston 7 movably provided in a cylindrical cylinder 3 (movable in a direction A or a direction B). A cylindrical piston rod 5-1 and a piston rod 5-2 are provided on both sides of the piston 7.

  The piston rod 5-2 is connected to the joint 33-2. The joint 33-1 is fixed to the support structure portion of the building. Further, the joint 33-2 is fixed to a brace of a building. The joint 33-1 may be fixed to a building brace or the like, and the joint 33-2 may be fixed to the building support structure. When the building vibrates due to wind or earthquake, the hydraulic damper 1 absorbs the vibration of the building.

  The inside of the cylinder 3 is divided into a first pressure chamber 9 and a second pressure chamber 11 by a piston 7. The first pressure chamber 9 and the second pressure chamber 11 are filled with hydraulic oil. The cylinder 3, piston 7, piston rods 5-1, 5-2 and the like are made of metal.

  The first pressure chamber 9 is connected to the second pressure chamber 11 through the flow channel 13-1 and the flow channel 13-2. When the hydraulic valve 15 is inserted between the flow path 13-1 and the flow path 13-2 and the hydraulic valve 15 is opened, the hydraulic oil is bidirectionally transmitted by the pressure difference between the flow path 13-1 and the flow path 13-2. It is configured to be movable. Details of the hydraulic valve 15 will be described later.

  The flow path 13-1 branches into the flow path 23-1, and a check valve 25-1 and a fixed throttle 27-1 are provided in the flow path 23-1. The check valve 25-1 and the fixed throttle 27-1 are connected in parallel, and the flow path 23-1 is branched to the flow path 31 and connected to the accumulator 29. The flow path 23-1 branches to the flow path 21 and is connected to a chamber 19 behind the hydraulic valve arranged behind the hydraulic valve 15. Moreover, the flow path 23-1 branches into the flow path 23-2, and is connected to the flow path 13-2 via the check valve 25-2 and the fixed throttle 27-2. The check valve 25-2 and the fixed throttle 27-2 are connected in parallel. The flow path 13-2 is connected to the second pressure chamber 11.

  When the accumulator 29 side has a higher pressure than the first pressure chamber 9, the check valve 25-1 allows hydraulic oil to flow from the accumulator 29 side to the first pressure chamber 9. In addition, the check valve 25-1 prevents hydraulic oil from flowing from the first pressure chamber 9 into the accumulator 29. The fixed throttle 27-1 provided in parallel with the check valve 25-1 is provided for the purpose of letting the volume expanded by the temperature rise of the hydraulic oil to the accumulator.

  When the accumulator 29 side has a higher pressure than the second pressure chamber 11, the check valve 25-2 allows hydraulic oil to flow into the second pressure chamber 11 from the accumulator 29 side. Further, the check valve 25-2 prevents hydraulic oil from flowing from the second pressure chamber 11 into the accumulator 29. The fixed throttle 27-2 provided in parallel with the check valve 25-2 is provided for the purpose of letting the volume expanded by the temperature rise of the hydraulic oil to the accumulator.

  The accumulator 29 absorbs the thermal expansion of the hydraulic oil. In addition, the hydraulic oil is supplied from the accumulator 29 to the low pressure side pressure chamber during operation, thereby preventing the hydraulic oil from becoming negative pressure and stabilizing the performance of the hydraulic damper 1.

(1-2. Configuration of Hydraulic Valve 15)
The hydraulic valve 15 is disposed between the flow path 13-1 and the flow path 13-2. In a normal state (the piston 7 is not operating), the hydraulic valve 15 is supported by the elastic body 17 and blocks the flow path 13-1 and the flow path 13-2. Further, the pressure of the hydraulic oil that opens the hydraulic valve 15 and the flow rate of movement between the flow path 13-1 and the flow path 13-2 are controlled by the elastic force of the elastic body 17. Further, the hydraulic oil in the chamber 19 behind the hydraulic valve flows in the direction of the flow path 21 when the hydraulic valve 15 moves in a direction in which the elastic body 17 is compressed. The hydraulic valve 15 and the elastic body 17 form a pressure adjusting unit.

  FIG. 2 shows the structure of the hydraulic valve 15 in detail. FIG. 2 shows a hydraulic valve 15 called a poppet valve, and a front view of the hydraulic valve 15 is shown in FIG.

  When hydraulic fluid flows from the flow path 13-1 side (direction C side), the hydraulic valve 15 receives a force in the same pressure receiving area S2 as the diameter d2 of the flow path 13-1. On the other hand, when hydraulic fluid flows from the flow path 13-2 side (direction D side), the hydraulic valve 15 receives a force at the portion of the tapered portion 37 in the donut-shaped pressure receiving area S1.

  When the hydraulic oil force from the direction C side reaches a certain set value, the elastic body 17 is compressed and the hydraulic valve 15 is opened, and the hydraulic oil flows from the flow path 13-1 to the flow path 13-2. . Conversely, when the force of the hydraulic oil from the direction D side reaches the same set value as the force from the direction C side, the elastic body 17 is compressed and the hydraulic valve 15 is opened, and the hydraulic oil flows into the flow path 13−. 2 to the flow path 13-1. The hydraulic valve 15 is configured such that the force received by the pressure receiving area S1 = the force received by the pressure receiving area S2.

(2. Operation of hydraulic damper 1)
Next, the operation of the hydraulic damper 1 will be described with reference to FIGS. 1 and 2.

  Assume that an external force such as an earthquake or wind acts on the building, and a force in direction A acts on the piston 7 in FIG. The hydraulic oil filled in the first pressure chamber 9 is compressed and flows to the flow path 13-1. That is, the hydraulic oil flows in the direction C in FIG. In a state where no external force is applied to the building, the hydraulic valve 15 receives the elastic force of the elastic body 17 and is in a state of blocking the flow path 13-1 and the flow path 13-2. When the piston 7 moves in the direction A and the hydraulic oil pressure in the direction C applied to the hydraulic valve 15 becomes equal to or higher than a predetermined pressure, the hydraulic valve 15 and the elastic body 17 are compressed and moved to flow from the flow path 13-1. The hydraulic oil moves in the direction of the path 13-2.

  2 is applied to the pressure receiving area S2 (equal to the diameter d2 of the flow path 13-1) of the hydraulic valve 15 in FIG.

  By adjusting the shape of the hydraulic valve 15 and the spring of the elastic body 17 with respect to the speed at which the piston 7 moves, a damping force is generated in the direction opposite to the force by which the piston 7 compresses the hydraulic oil. In other words, the damping characteristic of the hydraulic damper 1 can be adjusted by adjusting the hydraulic valve 15 and the elastic body 17.

  When the hydraulic valve 15 and the elastic body 17 move, the hydraulic oil filled in the chamber 19 behind the hydraulic valve flows into the flow path 21. Since the flow path 21 has a higher pressure than the flow path 23-2, the check valve 25-2 is opened to allow the hydraulic oil to flow into the flow path 23-2. The hydraulic oil also flows into the accumulator 29.

  When the pressure in the direction C applied to the hydraulic valve 15 is eliminated, the hydraulic valve 15 and the elastic body 17 are returned to their original positions, and the flow path 13-1 and the flow path 13-2 are blocked again.

  Next, when the piston 7 moves in the direction B, the hydraulic oil filled in the second pressure chamber 11 is compressed and flows to the flow path 13-2. That is, hydraulic fluid flows in the direction D of FIG. When the piston 7 moves in the direction B and the pressure of the hydraulic oil in the direction D applied to the hydraulic valve 15 becomes equal to or higher than a predetermined pressure, the hydraulic valve 15 and the elastic body 17 are compressed and moved to move from the flow path 13-2. The hydraulic oil moves in the direction of the flow path 13-1.

  That is, the pressure of the hydraulic oil is applied to the pressure receiving area S1 of the hydraulic valve 15 in FIG. 2 (the donut shape having the diameter d1 of the cylindrical portion of the hydraulic valve 15 as the outer diameter and the diameter d2 of the flow path 13-1 as the inner diameter). It takes.

  When the hydraulic valve 15 and the elastic body 17 move, the hydraulic oil filled in the chamber 19 behind the hydraulic valve flows into the flow path 21. Since the flow path 21 has a higher pressure than the flow path 23-1, the check valve 25-1 is opened to allow the hydraulic oil to flow into the flow path 23-1. The hydraulic oil also flows into the accumulator 29.

  When the pressure in the direction D applied to the hydraulic valve 15 is eliminated, the hydraulic valve 15 and the elastic body 17 are returned to their original positions, and the flow path 13-1 and the flow path 13-2 are blocked again.

  In addition, with the vibration of the building, the piston 7 repeats the movement in the direction A and the direction B. At this time, the accumulator 29 has a function of supplying hydraulic oil to the low pressure side and absorbing thermal expansion of the hydraulic oil.

  As described above, even when the piston 7 moves in either the direction A or the direction B, one pressure adjusting unit, that is, one hydraulic valve 15 and the elastic body 17 provide the damping characteristic of the hydraulic damper 1. decide.

  Note that the force received by the pressure receiving area S2 from the direction C of the hydraulic valve 15 and the force received by the pressure receiving area S1 from the direction D are made equal to obtain the same damping characteristic with respect to the bidirectional movement of the piston 7. To do. The shape of the tapered portion 37 of the hydraulic valve 15, the area of the hydraulic valve 15 viewed from the direction C in the vertical direction, and the like may be adjusted. That is, when the pressure of the hydraulic oil from the direction C when the piston 7 moves in the direction A and the pressure of the hydraulic oil from the direction D when the piston 7 moves in the direction B become the same critical value, respectively. The hydraulic valve 15 moves to open the flow path 13-1 and the flow path 13-2.

(3. Other embodiments)
Next, a hydraulic valve according to another embodiment will be described. FIG. 3 shows a hydraulic valve 39 provided with a structure for adjusting the fluid force acting on the hydraulic valve.

  The hydraulic valve 39 shown in FIG. 3 is provided with a stepped structure 43 at the connecting portion between the cylindrical portion 41 and the conical portion 45. Further, a protruding structure 47 is provided at the tip of the conical shape 45, and a tapered shape 49 is applied to the protruding structure 47.

  By providing the stepped structure 43 and the protruding structure 47, the fluid force acting on the hydraulic valve can be adjusted.

  In FIG. 3A, when the piston 7 moves in the direction A, the hydraulic oil flows in the direction C from the flow path 13-1 and pressure is applied to the hydraulic valve 39. When the pressure exceeds a predetermined value, the elastic body 17 is compressed, the hydraulic valve 39 moves, and hydraulic oil flows from the flow path 13-1 to the flow path 13-2. At this time, the force of compressing the elastic body can be further increased by the fluid force acting on the portion of the stepped structure 43.

  In FIG. 3B, when the piston 7 moves in the direction B, hydraulic oil flows from the flow path 13-2 in the direction D, and pressure is applied to the hydraulic valve 39. When the pressure exceeds a predetermined value, the elastic body 17 is compressed, the hydraulic valve 39 moves, and the hydraulic oil flows from the flow path 13-2 to the flow path 13-1. At this time, the force of compressing the elastic body can be reduced by applying a fluid force to the tapered portion 49 of the projecting structure 47 as compared with the case where only the pressure is applied.

  Similar to the above-described hydraulic valve, the hydraulic valve 39 has a structure that obtains the same damping characteristic with respect to the bidirectional movement of the piston 7. That is, hydraulic oil from direction C and hydraulic oil from direction D open hydraulic valve 39 at the same critical point pressure. The hydraulic valve 39 may have a structure including both the stepped structure 43 and the protruding structure 47, or may have a structure including only one of them.

  Next, FIG. 4 shows a hydraulic valve 51 according to another embodiment. The hydraulic valve 51 in FIG. 4 has a structure in which a cylindrical portion 53 and a cylindrical portion 55 are connected. The shape of the hydraulic valve 51 is referred to as a spool valve. The hydraulic oil pressure from the flow channel 13-1 is received by the cylindrical portion 55, and the hydraulic oil pressure from the flow channel 13-2 is received by the step portion between the cylindrical portion 53 and the cylindrical portion 55.

  Similar to the other hydraulic valves, the hydraulic valve 51 has a structure that obtains the same damping characteristic with respect to the bidirectional movement of the piston 7.

  Next, FIG.5 and FIG.6 shows the hydraulic valve 51 which provided the small diameter holes 59-1, 59-2 inside. As shown in FIG. 6, a small-diameter hole 59-1 is provided between the chamber 19 behind the hydraulic valve and the flow path 13-1, and a small-diameter hole 59-2 is provided between the chamber 19 behind the hydraulic valve and the flow path 13-2. .

  By providing the small diameter holes 59-1 and 59-2 in the hydraulic valve 51, fixed throttles (fixed throttles 27-1 and 27 in FIG. 1) inserted in the flow paths 23-1 and 23-2 as shown in FIG. -2) can be omitted. The small-diameter holes 59-1 and 59-2 are provided for the purpose of letting the volume expanded due to the temperature rise of the hydraulic oil to the accumulator, like the fixed throttle.

  Therefore, the use of the hydraulic valve 51 provided with the small-diameter holes 59-1 and 59-2 has an effect of reducing circuit parts and further reducing the size of the hydraulic damper 1.

  Next, FIG.7 and FIG.8 shows the hydraulic valve 61 which provided the small diameter holes 65-1, 65-2 and the check valves 63-1, 63-2 inside. As shown in FIG. 8, a small diameter hole 65-1 and a check valve 63-1 are provided in parallel between the chamber 19 behind the hydraulic valve and the flow path 13-1, and the chamber 19 and the flow path 13-2 behind the hydraulic valve are provided. A small-diameter hole 65-2 and a check valve 63-2 are provided in parallel therebetween.

  By providing the hydraulic valve 61 with small-diameter holes 65-1, 65-2 and check valves 63-1, 63-2, a flow path for releasing hydraulic oil from the chamber 19 behind the hydraulic valve as shown in FIG. 7 (FIG. 1). The flow path 21) can be omitted. The check valves 63-1 and 63-2 have a function of releasing the hydraulic oil compressed in the chamber 19 behind the hydraulic valve. The small diameter holes 65-1 and 65-2 are provided to supply hydraulic oil to the chamber behind the hydraulic valve when the hydraulic valve is about to return to the original position.

  Therefore, by using the hydraulic valve 61 provided with the small diameter holes 65-1, 65-2 and the check valves 63-1, 63-2, it is possible to reduce the flow path and further reduce the size of the hydraulic damper 1. There is.

  Next, FIG. 9 shows a hydraulic type in which a pressure regulating unit (hydraulic valve 15, elastic body 17, chamber 19 behind the hydraulic valve, etc.) and other flow paths and circuits are incorporated in the piston 7 and the piston rod 67-1. The damper 1 is shown. The accumulator 69 is housed in the piston rod 67-1.

  The operations and functions of the hydraulic damper 1 shown in FIG. 9 are the same as those shown in FIG. 1 and will not be described. However, by installing a pressure regulating unit, a flow path, a circuit, etc. in the piston 7, There is an effect that the damper 1 can be further reduced in size.

(3. Effects, etc.)
Thus, in the present embodiment, the pressure regulating function for determining the damping function of the hydraulic damper is not provided separately for the bi-directional movement of the piston, but is also performed by a single hydraulic valve. A suppressed hydraulic damper can be provided.

  Moreover, the adjustment time of the damping function can be shortened by using one hydraulic valve. Therefore, there is an effect of reducing the cost required for adjusting the hydraulic damper.

  Moreover, the hydraulic damper itself can be reduced in size by using one hydraulic valve.

  Further, by providing a small diameter hole and a check valve inside the hydraulic valve, it is possible to further reduce the size of the hydraulic damper.

The technical scope of the present invention is not limited to the embodiment described above. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these are naturally within the technical scope of the present invention. Understood.
For example, in each of the embodiments described above, a hydraulic valve (pressure regulating valve) is used as the pressure regulating unit, but a relief valve or other valve having a pressure regulating action may be used.

Configuration diagram of hydraulic damper 1 in the present embodiment The figure which shows the structure of the hydraulic valve 15 The figure which shows the structure of the hydraulic valve 39 of another embodiment. The figure which shows the structure of the hydraulic valve 51 of another embodiment. The block diagram of the hydraulic damper 1 in another embodiment The figure which shows the structure of the hydraulic valve 57 The block diagram of the hydraulic damper 1 in another embodiment The figure which shows the structure of the hydraulic valve 61 The block diagram of the hydraulic damper 1 in another embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ......... Hydraulic damper 3 ......... Cylinder 5-1, 5-2, 67-1, 67-2 ......... Piston rod 7 ......... Piston 9 ......... First pressure chamber 11 ......... First 2 pressure chambers 13-1, 13-2, 21, 23-1, 23-2, 31, 75-1, 75-2, 77-1, 77-2, 77-3, 77-4 ......... flow Paths 15, 39, 51, 57, 61 ......... Hydraulic valve 17 ......... Elastic body 19 ......... Rooms 25-1, 25-2, 63-1, 63-2, 71-1, behind the hydraulic valve, 71-2 ......... Check valves 27-1, 27-2, 73-1, 73-2 ......... Fixed throttles 29, 69 ...... Accumulators 33-1, 33-2 ......... Joint 35 ......... Front view of the hydraulic valve 37 ......... Tapered structure 41, 53, 55 ... Cylindrical part 43 ......... Stepped structure 45 ......... Conical part 47 ......... Projection Protruding structure 49 ... Projection taper structure 59-1, 59-2, 65-1, 65-2 ... Small hole

Claims (7)

A cylinder filled with hydraulic oil;
A piston that moves in the cylinder and divides the cylinder into a first pressure chamber and a second pressure chamber;
Piston rods provided on both sides or one side of the piston;
In the hydraulic damper having a flow path communicating the first pressure chamber and the second pressure chamber,
The flow path is provided with at least one pressure regulating portion composed of one hydraulic valve and an elastic body that supports the hydraulic valve,
The hydraulic damper is characterized in that when the piston moves on the operating shaft in both directions at the same speed, the pressure adjusting section makes damping forces generated in both directions substantially the same.   The hydraulic damper according to claim 1, wherein the hydraulic valve is provided with a structure for adjusting a magnitude of a fluid force acting on the hydraulic valve.   The hydraulic damper according to claim 2, wherein the hydraulic valve is provided with a projecting structure and / or a stepped structure for adjusting a fluid force.   The hydraulic damper according to claim 1, wherein a chamber is provided behind the hydraulic valve, and a flow path for discharging the fluid in the chamber is provided.   In the hydraulic valve, between the flow path communicating with the chamber behind the hydraulic valve and the first pressure chamber, and between the flow channel communicating with the chamber behind the hydraulic valve and the second pressure chamber, 5. The hydraulic damper according to claim 4, wherein a small diameter hole is provided for each.   In the hydraulic valve, between the flow path communicating with the chamber behind the hydraulic valve and the first pressure chamber, and between the flow channel communicating with the chamber behind the hydraulic valve and the second pressure chamber, 2. The hydraulic damper according to claim 1, wherein each of the small diameter holes and the check valve is provided in parallel. The hydraulic damper according to claim 1, wherein the flow path and the pressure adjusting unit are accommodated in the piston.

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