JP7744636B2 - Fluid Control Valve - Google Patents

Description

This invention relates to a fluid control valve with a simple mechanical structure that can appropriately control fluid flow by smoothing fluid flow in one direction, and by throttling the fluid in the opposite direction (returning the fluid in the one direction) and then releasing the throttling to allow smooth flow.

An example of a mechanical element that is operated by fluid control is an oil damper that absorbs earthquake energy.

Patent Document 1 is known as an example of this type of oil damper. The "oil damper for a seismic isolation device" in Patent Document 1 is an oil damper for a seismic isolation device that, when used in combination with a seismic isolation bearing, constitutes a seismic isolation device and absorbs and attenuates the energy of earthquake shaking in order to suppress relative displacement between the foundation and the upper building during an earthquake. The oil damper comprises a first cylinder connected to one of the foundation and the upper building, a first piston slidably disposed within the first cylinder and dividing the first cylinder into two oil chambers, left and right, a first hydraulic cylinder having a pressing portion, a piston rod integrally disposed with the first piston, and connected to the other of the foundation and the upper building, a communication passage outside the first hydraulic cylinder that connects the two oil chambers to each other, a valve body disposed midway in the communication passage that opens and closes the communication passage, a movable spring seat, and a spring that is disposed between the valve body and the spring seat and biases the valve body toward the closing side. The damping valve has a spring that is inserted into the damping valve seat and a spring seat. As the first piston of the first hydraulic cylinder is displaced, the valve element opens due to hydraulic pressure supplied from the oil chamber of the first cylinder, generating a damping force. The damping valve also has a second cylinder that communicates with the back side of the spring seat of the damping valve, a second piston that is slidably disposed within the second cylinder, and a second piston rod that has an engaging portion and is integral with the second piston. When the displacement of the first piston reaches a predetermined value, the engaging portion is pressed by the pressing portion of the first piston rod, and the second hydraulic cylinder introduces hydraulic pressure from within the second cylinder to the back side of the spring seat, compressing the spring via the spring seat and increasing the spring force of the spring, thereby strengthening the damping force.

Patent No. 4442770

The oil damper disclosed in the background art introduces hydraulic pressure from within the second hydraulic cylinder to the back side of the spring seat of the damping valve when the displacement of the first piston reaches a predetermined value, increasing the spring force of the spring that biases the valve body that opens and closes the communication passage that connects to the first hydraulic cylinder, thereby strengthening the damping force. This is an excellent device that can change damping performance in response to the stroke of the first piston rod caused by seismic motion.

In this oil damper, the oil introduced to the back side of the spring seat is prevented from returning to the second cylinder by a check valve, but is allowed to do so by a minute passage with a needle valve installed in parallel with the check valve. Specifically, the oil on the back side passes through the minute passage and returns to the relay valve assembly via piping, and then passes through the throttle passage in the relay valve assembly and is returned to the second cylinder via piping (see paragraph [0040] of the above-mentioned Patent Document 1). This allows the damping valve to gradually return to its normal characteristics after the earthquake has subsided.

However, in the background art, it was difficult to adjust the device to return the oil slowly over time (approximately 4 to 5 minutes), and there was also the issue that the oil did not return completely to the second cylinder.

In addition, while it may be possible to use a solenoid valve for simplicity, there is the problem that it becomes unusable in the event of a power outage.

The present invention was devised in light of the above-mentioned problems with the prior art, and aims to provide a fluid control valve with a simple mechanical structure that can appropriately control fluid flow by smoothing fluid flow in one direction, and by throttling the fluid in the opposite direction (returning the fluid in the one direction) and then releasing the throttling to allow smooth flow.

The fluid control valve according to the present invention is a fluid control valve that is installed in a flow path and that allows fluid to flow in one direction and throttles the flow of fluid in the opposite direction. It comprises a flow path member having a passage portion through which fluid flows, with a first port and a second port at both ends that are connected to the flow path, a flow path that communicates with the first port and allows fluid to flow, and a spool that is installed in the passage portion so as to be slidable back and forth between the first port and the second port, a spring that is installed in the passage portion and elastically biases the spool from the second port side toward the first port side, and a spring that is installed in the flow path member. The valve includes a communication passage for connecting the passage portion with the flow passage, and a movable passage provided in the spool to communicate with the communication passage, the communication range of which changes as the spool slides back and forth. The movable passage has a communication range with the communication passage that expands when the spool slides toward the first port due to the elastic bias of the spring, and a communication range with the communication passage that narrows when the spool slides toward the second port against the elastic bias of the spring due to the fluid pressure acting on the spool from the first port side, restricting the flow of fluid.

The first port is provided with a spring force adjustment means that adjusts the spring force of the spring by changing the position of the spool that is elastically biased by the spring.

The spool's flow passage is characterized by having a pressure-receiving portion on which the fluid pressure acts.

The fluid control valve of the present invention has a simple mechanical structure and can appropriately control the flow of fluid by allowing smooth flow in one direction, and by restricting the flow of fluid in the opposite direction (returning the flow in the other direction) and then releasing the restriction to allow smooth flow.

1 is an explanatory diagram illustrating a preferred embodiment of a fluid control valve according to the present invention, illustrating a state in which a fluid flows in one direction. FIG. 2 is an explanatory diagram illustrating a state in which a fluid flows in the opposite direction through the fluid control valve shown in FIG. 1 . FIG. FIG. 2 is a perspective view showing an example of a spool provided in the fluid control valve shown in FIG. 1 . FIG. 2 is a perspective view showing an example of a screw member provided in the fluid control valve shown in FIG. 1 . 1 is an explanatory diagram illustrating a hydraulic circuit of an oil damper system that is an application example of a fluid control valve according to the present invention. FIG. FIG. 6 is a cross-sectional view illustrating a damping valve unit of the oil damper system of FIG. 5 . FIG. 6 is a cross-sectional view illustrating a control cylinder unit of the oil damper system of FIG. 5 . FIG. 6 is an explanatory diagram illustrating a control valve unit of the oil damper system of FIG. 5, which includes a fluid control valve according to the present invention.

A preferred embodiment of a fluid control valve according to the present invention will be described in detail below with reference to the accompanying drawings.

As shown in Figures 1 and 2, the fluid control valve 100 according to this embodiment is installed midway along a flow path 101 formed by piping, tubing, etc.

A fluid flows through the flow path 101. The fluid may be a liquid or a gas.

The fluid flows alternately back and forth within the flow path 101, first in one direction (indicated by arrow a in the figure) and then in the opposite direction (indicated by arrow b in the figure).

Figure 1(A) is a side cross-sectional view illustrating the state of the fluid control valve 100 when fluid flows in one direction a, and Figure 1(B) is a circuit diagram for that state. Figure 2(A) is a side cross-sectional view illustrating the state of the fluid control valve 100 when fluid flows in the opposite direction b, and Figure 2(B) is a circuit diagram for that state.

The fluid control valve 100 according to this embodiment is primarily composed of a flow path member 102 disposed in the flow path 101, and a spool 103 and a coil spring 104 housed within the flow path member 102.

The flow path member 102 is composed of a first flow path body 105 and a second flow path body 106 connected in series in the direction of fluid flow.

The first flow path body 105 is formed as a large-diameter hollow cylinder with one longitudinal end open and a first end wall 105a at the other longitudinal end. Inside the first flow path body 105, a first passage section 105c is defined inside the inner circumferential wall 105b.

The opening at one longitudinal end of the first flow path body 105 forms a first port 107 that connects to the flow path 101.

A female thread portion 105d is formed in the first flow path body 105, extending from the first port 107 toward the inside of the first passage portion 105c.

A through hole 105e is formed in the first end wall 105a for connecting the second flow path body 106.

The second flow path body 106 is formed as a hollow cylinder with a smaller diameter than the first flow path body 105, with one longitudinal end open and a second end wall 106a at the other longitudinal end. A second flow path section 106b with a smaller diameter than the first flow path section 105c is defined within the second flow path body 106.

A through hole that forms the second port 108 connected to the flow path 101 is formed in the second end wall 106a.

One longitudinal end of the open second flow path body 106 is inserted into and joined to the through-hole 105e of the first flow path body 105, thereby connecting the second flow path body 106 to the first flow path body 105.

By connecting the first flow path body 105 and the second flow path body 106, the flow path member 102 is provided with a first port 107 and a second port 108 connected to the flow path 101 at both ends in the longitudinal direction, and the communication between the first passage portion 105c and the second passage portion 106b forms a passage portion that allows fluid to flow between the first port 107 and the second port 108.

In the illustration, the flow path member 102 is shown with the second flow path body 106 provided above the first flow path body 105, with the first port 107 facing downwards and the second port 108 facing upwards, so that the passage sections are oriented vertically. However, the flow path member 102 may be used in any orientation, such as with the second flow path body 106 provided below the first flow path body 105, with the first port 107 facing upwards and the second port 108 facing downwards, or with the passage sections (first and second flow path sections 105c, 106b) oriented horizontally or diagonally instead of vertically.

A circular screw member 109 with a male thread 109a formed on its outer periphery is threadedly fitted into the female thread 105d on the first port 107 side of the flow path member 102, and serves as a spring force adjustment means, which will be described later.

A spool 103 is provided inside the first flow path body 105. The spool 103 is formed as a solid cylinder that slides against the inner peripheral wall 105b of the first flow path body 105, and is provided within the first passage portion 105c that constitutes the passage, between the first port 107 and the second port 108, specifically between the first port 107 and the first end wall 105a of the first flow path body 105, so that it can slide back and forth.

The spool 103 is blocked by the first end wall 105a and cannot move to the second passage portion 106b of the second flow path body 106, and can only move within the first passage portion 105c of the first flow path body 105.

As shown in Figure 3, the spool 103 is formed with a flat surface 103a at one longitudinal end of the flow path member 102 on the first port 107 side so that it can abut against the screw member 109, and a recess 103c is formed at the other longitudinal end on the second port 108 side, surrounded by an annular protrusion 103b.

The inner diameter of the recess 103c is formed to be approximately the same as the inner diameter of the second passage portion 106b of the second flow path body 106.

When the spool 103 is slid toward the first end wall 105a, the annular protrusion 103b surrounding the recess 103c approaches and abuts the end wall 105a. When the spool 103 is slid toward the first port 107, the tip of the annular protrusion 103b moves away from the first end wall 105a.

At least one movable passage 103d is formed in the annular convex portion 103b by cutting out a predetermined length in the depth direction of the recess 103c at appropriate locations around the circumference, connecting the recess 103c to the outside of the spool 103.

In the illustrated example, two movable passages 103d are formed in the diameter direction of the annular convex portion 103b. The movable passages 103d may also be elongated holes formed with a predetermined length in the depth direction of the recess 103c without being cut out.

The spool 103 has a reduced diameter section 103e formed in the middle between one longitudinal end and the other. A flow passage 103f, through which fluid flows in from the first port 107, is formed in the spool 103 between the reduced diameter section 103e and the flat surface 103a that forms one end of the spool 103.

In this embodiment, the flow passage 103f is formed in a T-shape by a horizontal passage 103g that crosses the spool 103 in the diameter direction of the first passage portion 105c, and a vertical passage 103h that faces the first port 107 from the horizontal passage 103g, and the horizontal passage 103g forms a pressure-receiving portion that receives fluid pressure.

The flow passage 103f only needs to be able to apply the fluid pressure of the fluid flowing in from the first port 107 to the spool 103, causing the spool 103 to slide, and its shape is not limited to a T-shape and may be any shape.

A coil spring 104 is provided within the second passage portion 106b of the second flow path body 106, which constitutes the passage portion.

One longitudinal end of the coil spring 104 is supported by the second end wall 106a of the second flow path body 106, and the other longitudinal end is supported by the recess 103c of the spool 103, with the recess 103c and the second end wall 106a serving as spring seats.

The coil spring 104 elastically biases the spool 103 from the second port 108 side toward the first port 107 side.

The spool 103, which is elastically biased by the coil spring 104, is supported within the first passage portion 105c so as not to be removed from the first flow path body 105, as the flat surface 103a at one end of the spool abuts against a screw member 109 that is threaded into the female thread portion 105d on the first port 107 side.

As shown in Figure 4, the screw member 109 is formed in an annular shape, thereby ensuring fluid flow through the first port 107.

The male thread portion 109a on the outer surface of the screw member 109 is threadedly engaged with the female thread portion 105d of the first flow path body 105, allowing it to be detachably attached to the flow path member 102. By threading the screw member 109 shallowly into the first flow path portion 105c, the reciprocating sliding range of the spool 103 is widened, while by threading it deeply into the inner depths of the first flow path portion 105c, the reciprocating sliding range of the spool 103 is narrowed.

In the figure, the screw member 109 has a groove 109b formed in the diameter direction, into which a tool such as a screwdriver can be engaged to adjust the amount of engagement.

To explain the assembly method, the coil spring 104 is attached to the second passage portion 106b of the second flow path body 106, and then the spool 103 is inserted into the first passage portion 105c of the first flow path body 105. After that, the screw member 109 is screwed into the female thread portion 105d of the first flow path body 105, and the spool 103, which is supported by the screw member 109, is elastically biased by the coil spring 104.

By changing the position of the spool 103 by increasing or decreasing the amount of threading of the screw member 109, which is attached closer to the first port 107 than the spool 103, the spring force of the coil spring 104 can be increased or decreased.

The first flow path body 105 has a communication path 105f that is constantly connected to the flow path 103f. The communication path 105f is formed by recessing the first passage portion 105c into a groove or recess of a predetermined width in the direction of reciprocating movement of the spool 103 from a position that is a shorter distance (see dimension x in the figure) from the first end wall 105a of the first flow path body 105 in the length direction of the movable passage 103d formed in the spool 103, and is located toward the first port 107.

The specified width is preferably equal to or greater than the width of the movable passage 103d to ensure communication with the movable passage 103d.

Instead of forming the communication passage 105f by recessing it, it may be formed by expanding the inner diameter of the first passage portion 105c around its entire inner circumferential surface.

The closer the spool 103 is to the first end wall 105a, the narrower the fluid flow path becomes.

The dimension x may be longer than the movable passage 103d. In that case, the flow passage 103f and the communication passage 105f are connected by an extremely narrow gap between the inner periphery of the first flow passage body 105 and the outer periphery of the annular convex portion 103b of the spool 103.

The movable passage 103d is also constantly connected to the communication passage 105f, thereby constantly connecting the first passage portion 105c and the second passage portion 106b.

The communication range between the communication passage 105f and the movable passage 103d of the spool 103 is increased or decreased as the spool 103 slides back and forth. When the tip of the annular convex portion 103b abuts against the first end wall 105a, the communication is narrowed to its narrowest, and when the tip of the annular convex portion 103b moves away from the first end wall 105a, the communication is widened.

When the spool 103 moves toward the first port 107 and the annular convex portion 103b moves to the position of the communication passage 105f, the communication passage 105f of the first flow path body 105 is directly connected to the second passage portion 106b.

When the spool 103 is slidably moved toward the first port 107 by the elastic force of the coil spring 104 and the spool 103 is abutted against the screw member 109, the range of communication with the communication passage 105f of the movable passage 103d widens. Furthermore, when the spool 103 is slidably moved toward the second port 108 against the elastic force of the coil spring 104 due to the fluid pressure of the fluid flowing in from the first port 107 and acting on the spool 103 through the flow passage 103f, the range of communication with the communication passage 105f narrows, restricting the flow of fluid.

"Throttling the flow of fluid" means to apply the brakes to the flow of fluid; more specifically, it means reducing the flow rate Qa per unit time when the fluid is flowing in the opposite direction compared to the flow rate Q per unit time when the fluid is flowing in one direction (Qa < Q).

Next, the operation of the fluid control valve 100 according to this embodiment will be described. When no fluid is flowing through the fluid control valve 100 according to this embodiment, as shown in FIG. 1, the spool 103 is moved toward the first port 107 by the elastic force of the coil spring 104, and the spool 103 is positioned with its flat surface 103a abutting against the screw member 109.

At this time, the communication range between the movable passage 103d and the communication passage 105f is maximized, and the second port 108 is connected to the first port 107 via the second passage portion 106b, the communication passage 105f, and the flow passage 103f in the first passage portion 105c.

When fluid flows in one direction from the second port 108 to the first port 107, as shown in Figure 1, the spool 103 is elastically biased toward the first port 107 by the coil spring 104, the communication range between the movable passage 103d and the communication passage 105f is expanded, and the second passage portion 106b and the first passage portion 105c are directly connected, allowing the fluid to flow smoothly in one direction, as indicated by arrow a in the figure.

On the other hand, when fluid flows in the opposite direction, from the first port 107 to the second port 108, the fluid pressure of the fluid flowing from the first port 107 into the first passage portion 105c acts on the spool 103 via the T-shaped flow passage 103f.

As a result, as shown in Figure 2, the fluid pressure compresses the coil spring 104, causing the spool 103 to slide toward the second port 108. At this time, the flat surface 103a of the spool 103 also becomes a pressure-receiving portion.

The sliding movement of the spool 103 narrows the communication range between the movable passage 103d and the communication passage 105f. As a result, the fluid flowing in from the first port 107 is throttled as it flows from the communication passage 105f through the movable passage 103d into the second passage portion 106b, as shown by arrow b in the figure, and is forced to flow to the second port 108.

Subsequently, when the fluid pressure of the fluid flowing in the opposite direction decreases and the elastic force of the coil spring 104 becomes dominant, the spool 103 slides toward the first port 107, expanding the communication range between the movable passage 103d and the communication passage 105f. The second passage portion 106b and the first passage portion 105c then directly communicate with each other, returning to the state shown in Figure 1, and the fluid flows smoothly in the opposite direction, as indicated by arrow c in the figure.

In the fluid control valve 100 of this embodiment, when the spool 103 is slidably moved toward the first port 107 due to the elastic bias of the coil spring 104, the communication range between the movable passage 103d and the communication passage 105f expands, allowing fluid to flow in one direction, from the second port 108 to the first port 107. On the other hand, when the spool 103 is slidably moved toward the second port 108 against the elastic bias of the coil spring 104 due to the fluid pressure of the fluid flowing from the first port 107 into the first passage portion 105c and acting on the spool 103, the communication range between the movable passage 103d and the communication passage 105f narrows, allowing fluid to flow in the opposite direction, from the first port 107 to the second port 108, while throttling the flow of fluid. This allows for appropriate control of the smooth flow of fluid in one direction and the throttling of the fluid in the opposite direction, which is the return flow of the fluid.

Then, in the return flow in the opposite direction, as the fluid pressure drops, the spool 103 is again slid toward the first port 107 due to the elastic force of the coil spring 104, widening the communication range between the movable passage 103d and the communication passage 105f. This ensures that the fluid that has been released from the restriction can return, allowing for appropriate control of smooth flow without residual fluid remaining.

The fluid control valve 100 according to this embodiment has a first port 107 and a second port 108 connected to the flow path 101 at both ends, and includes first and second flow path bodies 105, 106 provided with first and second passage sections 105c, 106b through which fluid flows, and a flow path 103f connected to the first port 107 through which fluid flows. The fluid control valve 100 also includes a spool 103 provided in the first passage section 105c so as to be slidable back and forth between the first port 107 and the second port 108, and a coil spring 104 provided in the second passage section 106b, which elastically biases the spool 103 from the second port 108 side toward the first port 107 side. 4, a communication passage 105f provided in the first flow path body 105 for connecting the first passage portion 105c and the flow path 103f, and a movable passage 103d provided in the spool 103 so as to communicate with the communication passage 105f, the range of communication with the communication passage 105f being changed by the sliding movement of the spool 103 in the reciprocating direction. The mechanical elements are the hollow cylindrical flow path member 102, the solid cylindrical spool 103, and the coil spring 104, and the flow path 103f, communication passage 105f, and movable passage 103d are machined, but the excellent fluid control described above can be achieved.

In addition, because it is mechanical, it can constantly and accurately control fluid without being affected by power outages or other issues.

A screw member 109 is provided on the first port 107 side of the spool 103 as a spring force adjustment means for adjusting the spring force of the coil spring 104 by changing the position of the spool 103, which is elastically biased by the coil spring 104. This allows the communication range between the movable passage 103d and the communication passage 105f to be freely and preferably adjusted.

A pressure-receiving section (side passage 103g) on which the fluid pressure acts is formed in the flow passage 103f of the spool 103, and by utilizing the fluid flow path, the fluid pressure can be appropriately applied to the spool 103 with a compact configuration.

Next, application examples of the fluid control valve 100 according to this embodiment will be described with reference to Figures 5 to 8.

Figure 5 is an explanatory diagram illustrating the hydraulic circuit of an oil damper system, which is an application example; Figure 6 is a cross-sectional view illustrating a damping valve unit of the oil damper system; Figure 7 is a cross-sectional view illustrating a control cylinder unit of the oil damper system; and Figure 8 is an explanatory diagram illustrating a control valve unit of the oil damper system equipped with a fluid control valve according to this embodiment.

The oil damper system 1 is installed between the vibration input side and the vibration damping target side, for example, between the ground 2 or the foundation of a building 3 that moves integrally with the ground 2 to absorb earthquake energy, and the building 3 supported on the foundation by seismic isolation bearings.

The oil damper system 1 is primarily composed of a uniflow type cylinder unit 4.

The uniflow cylinder unit 4 itself is known and comprises an outer cylinder 5, a hydraulic oil reservoir 6 disposed within the outer cylinder 5 and storing hydraulic oil F with a free surface, an inner cylinder 7 disposed within the outer cylinder 5, a piston 8 slidably disposed within the inner cylinder 7 in a liquid-tight manner and dividing the interior of the inner cylinder 7 into two hydraulic oil outlet chambers R1 and R2, a piston rod 9 integrally connected to the piston 8, which penetrates the inner cylinder 7 and protrudes liquid-tightly outward from the outer cylinder 5, and is slidably operable, a first damper check valve 11 disposed between the hydraulic oil reservoir 6 and the hydraulic oil inlet chamber R2 and allows hydraulic oil F to flow only from the hydraulic oil reservoir 6 to the hydraulic oil inlet chamber R2 and blocks backflow, and a second damper check valve 12 disposed on the piston 8 and allows hydraulic oil F to flow only from the hydraulic oil inlet chamber R2 to the hydraulic oil outlet chamber R1 and blocks backflow.

In the uniflow type cylinder unit 4, when the piston 8 reciprocates, the hydraulic oil in the hydraulic oil outlet chamber R1 flows out into the outer cylinder 5, and at the same time, hydraulic oil flows from the outer cylinder 5 into the hydraulic oil inlet chamber R2, so that the hydraulic oil flows in one direction.

The pressure-receiving area of the piston 8 on the hydraulic oil outflow chamber R1 side to which the piston rod 9 is connected is set to half the cross-sectional area of the hydraulic oil inflow chamber R2 side, minus the cross-sectional area of the piston rod 9.

The oil damper system 1 is basically constructed by providing a damping valve unit 10 that generates energy absorption between the hydraulic oil outflow chamber R1 of the cylinder unit 4 and the hydraulic oil reservoir 6 in the outer cylinder 5.

As shown in Figure 6, the damping valve unit 10 is composed of a valve body 13 having a hydraulic oil inlet port P1 that communicates with the hydraulic oil outlet chamber R1 of the inner cylinder 7 and a hydraulic oil outlet port P2 that communicates with the hydraulic oil reservoir 6; a valve element 14 that is movably mounted within the valve body 13 and moves to open and close the hydraulic oil inlet port P1; a spring seat 15 that is positioned within the valve body 13 on the opposite side from the valve element 14 and is movably mounted in a liquid-tight manner relative to the valve body 13; and a pressure adjustment spring 16 that is sandwiched within the valve body 13 between the spring seat 15 and the valve element 14 and is supported by the spring seat 15 to bias the valve element 14.

That is, the valve body 14 is disposed at one end of the pressure adjustment spring 16, and the spring seat 15 is disposed at the other end of the pressure adjustment spring 16.

In the damping valve unit 10, the pressure regulating spring 16 biases the valve element 14 toward the hydraulic oil inlet port P1. The biasing force of the pressure regulating spring 16 causes the valve element 14 to close the hydraulic oil inlet port P1, thereby isolating the hydraulic oil outlet chamber R1 from the hydraulic oil reservoir 6. On the other hand, the valve element 14 opens the hydraulic oil inlet port P1 against the biasing force of the pressure regulating spring 16, thereby connecting the hydraulic oil inlet port P1 to the hydraulic oil outlet port P2, thereby connecting the hydraulic oil outlet chamber R1 to the hydraulic oil reservoir 6.

In the damping valve unit 10, hydraulic oil is pushed by the piston 8 and flows from the hydraulic oil outflow chamber R1 toward the outer cylinder 5. This causes the valve element 14 to move against the spring force of the pressure regulating spring 16, opening the hydraulic oil inlet port P1, causing a pressure loss in the hydraulic oil and absorbing energy.

The valve body 13 of the damping valve unit 10 is further provided with an inlet port P3 (described below) facing the back surface of the spring seat 15 (the side opposite to the side where the pressure adjustment spring 16 is installed).

The uniflow type cylinder unit 4 operates when the piston rod 9 is pulled out from the outer cylinder 5 in the protruding direction and the piston 8 moves to narrow the hydraulic oil outflow chamber R1 of the inner cylinder 7, causing hydraulic oil F to flow out of the hydraulic oil outflow chamber R1 toward the damping valve unit 10.

The outflow pressure of the hydraulic oil F flowing out of the hydraulic oil outflow chamber R1 acts on the hydraulic oil inlet port P1, moving the valve element 14, which is biased by the pressure regulating spring 16, against the spring force of the pressure regulating spring 16, thereby opening the hydraulic oil inlet port P1.

When the hydraulic oil inlet port P1 is opened, hydraulic oil F flows through the valve body 13 of the damping valve unit 10, through the gap between the inner surface of the valve body 13 and the valve element 14, toward the hydraulic oil outlet port P2, and then from the hydraulic oil outlet port P2 toward the hydraulic oil reservoir 6.

Furthermore, hydraulic oil F flows into hydraulic oil inlet chamber R2 via first damper check valve 11.

In the damping valve unit 10, the pressure regulating spring 16 limits the opening of the valve body 14 due to the outflow pressure of the hydraulic oil F from the hydraulic oil outflow chamber R1. In other words, by allowing the hydraulic oil F to continue to flow while maintaining the compressed state of the pressure regulating spring 16, the energy absorption function of the oil damper system 1 is exerted.

When the hydraulic oil outflow chamber R1 is narrowed and hydraulic oil F flows out of the hydraulic oil outflow chamber R1, hydraulic oil F flows into the hydraulic oil inflow chamber R2, which is widened, from the hydraulic oil reservoir 6 via the first damper check valve 11.

On the other hand, when the piston rod 9 is pushed in the retracting direction toward the outer cylinder 5 and the piston 8 moves to expand the hydraulic oil outflow chamber R1 of the inner cylinder 7, thereby narrowing the hydraulic oil inflow chamber R2, because the first damper check valve 11 is closed and, as described above, the pressure-receiving area on the hydraulic oil inflow chamber R2 side of the piston 8 is twice the pressure-receiving area on the hydraulic oil outflow chamber R1 side, the pressurized hydraulic oil F in the hydraulic oil inflow chamber R2 is sent through the piston 8's second damper check valve 12 into the hydraulic oil outflow chamber R1 in an amount twice that when the piston rod 9 extended, and half of that amount of hydraulic oil F is further pushed out of the hydraulic oil outflow chamber R1 and flows out toward the damping valve unit 10.

When twice the amount of hydraulic oil F flows into the hydraulic oil inlet chamber R2, half the amount of hydraulic oil F is replenished and the hydraulic oil outlet chamber R1 is always filled.

When the piston rod 9 is retracted, just as when it is extended, the outflow pressure of the hydraulic oil F flowing out of the hydraulic oil outflow chamber R1 acts on the hydraulic oil inlet port P1, moving the valve element 14, which is biased by the pressure regulating spring 16, against the spring force of the pressure regulating spring 16, thereby opening the hydraulic oil inlet port P1.

When the hydraulic oil inlet port P1 is opened, hydraulic oil F flows through the valve body 13 of the damping valve unit 10 toward the hydraulic oil outlet port P2, and then flows from the hydraulic oil outlet port P2 toward the hydraulic oil reservoir 6.

In the damping valve unit 10, even when the piston rod 9 is retracted, the pressure regulating spring 16 limits the opening of the valve body 14 due to the outflow pressure of the hydraulic oil F from the hydraulic oil outflow chamber R1. In other words, by maintaining the compressed state of the pressure regulating spring 16 while allowing the hydraulic oil F to continue to flow, the energy absorption function of the oil damper system 1 is exerted.

When the piston rod 9 extends or retracts, if the sliding distance of the piston 8 is the same, the amount of hydraulic oil F flowing into the damping valve unit 10 will be the same, and therefore the amount of energy absorption will be the same.

In the uniflow type cylinder unit 4 that constitutes the oil damper system 1, as described above, the hydraulic oil F flows in one direction, flowing only from the hydraulic oil outflow chamber R1 toward the hydraulic oil reservoir 6 and only from the hydraulic oil reservoir 6 into the hydraulic oil inflow chamber R2.

A relief valve 17 is provided between the hydraulic oil outflow chamber R1 and the hydraulic oil reservoir 6 to release and control the hydraulic pressure of the hydraulic oil F in the hydraulic oil outflow chamber R1 when the piston rod 9 operates at high speed.

The outer cylinder 5 of the cylinder unit 4 is connected to one of the vibration input side and the vibration damping target side, for example, the ground 2.

The piston rod 9 of the cylinder unit 4 is also connected to the other of the vibration input side and the vibration damping target side, for example, the building 3.

The cylinder unit 4 is installed by connecting it to, for example, the ground 2 and the building 3, and attachment portions 37 for these objects are provided on the piston rod 9 and outer cylinder 5 of the cylinder unit 4.

When an earthquake causes relative displacement between the ground 2 and the building 3, the piston rod 9 of the cylinder unit 4 itself moves forward or backward by a stroke amount corresponding to the amount of relative displacement.

In this specification, the "extension/retraction stroke of the piston rod 9" refers to the change in length of the cylinder unit 4, which occurs when the piston rod 9 is pulled outward from the outer cylinder 5 and inner cylinder 7 in a protruding direction or pushed inward in a retracted direction, accompanying the reciprocating movement of the piston 8, causing the length dimension of the cylinder unit 4 to increase or decrease in the length direction of the piston rod 9.

Similarly, the "extending stroke of the piston rod 9" refers to the change in the length of the cylinder unit 4 as it lengthens in the longitudinal direction of the piston rod 9, and the "retracting stroke of the piston rod 9" refers to the change in the length of the cylinder unit 4 as it shortens in the longitudinal direction of the piston rod 9.

These strokes represent the displacement of the cylinder unit 4 from its inoperative state, in which the piston rod 9 is stopped in its initial position.

Furthermore, "protruding" the piston rod 9 means that, as the piston 8 reciprocates, the piston rod 9 is pulled outward from the outer cylinder 5 and inner cylinder 7, increasing the length of the cylinder unit 4 in the direction of the piston rod 9; "retracting" the piston rod 9 means that the piston rod 9 is pushed inward into the outer cylinder 5 and inner cylinder 7, decreasing the length of the cylinder unit 4 in the direction of the piston rod 9.

As shown in Figure 5, the cylinder unit 4 is provided with a transmission member 18 that transmits the extension/retraction stroke amount of the piston rod 9 that moves the piston 8.

The transmission member 18 is formed as a shaft that is long in the direction of the extension/retraction stroke of the piston rod 9. The base end 18a, which is one longitudinal end of the transmission member 18, is attached to the piston rod 9, and the tip end 18b, which is the other longitudinal end, is supported movably on the outside of the outer cylinder 5.

The transmission member 18, whose base end 18a is attached to the piston rod 9, slides outside the cylinder unit 4 in accordance with the extension and retraction of the piston rod 9. When the piston rod 9 performs a protruding stroke, the tip 18b moves the same distance in the direction of the protruding stroke, and when the piston rod 9 performs a retracting stroke, the tip 18b moves the same distance in the direction of the retracting stroke.

A pair of control cylinder units 19, 19 are provided on the outside of the outer cylinder 5 of the cylinder unit 4, on either side of the transmission member 18, along the extension/retraction stroke direction of the piston rod 9.

One control cylinder unit 19 is configured to operate for the extension stroke of the piston rod 9, and the other control cylinder unit 19 is configured to operate for the retraction stroke.

As shown in Figure 7, each of these control cylinder units 19, 19 comprises a cylinder case 20, a control piston 21 that is slidably mounted in an airtight manner within the cylinder case 20 and divides the interior of the cylinder case 20 into an oil chamber 20a filled with control oil f and an air chamber 20c that is maintained at atmospheric pressure through an air hole 20b provided in the cylinder case 20, and a control piston rod that is slidably movable in and out of the cylinder case 20, with one end connected to the control piston 21 from the oil chamber 20a side and the other end protruding fluid-tightly outside the cylinder case 20. 22, and a control oil inlet/outlet port P4 that is provided in the cylinder case 20 and discharges control oil f from the oil chamber 20a, which is narrowed by the control piston 21 that slides when the control piston rod 22 protrudes, toward the damping valve unit 10.As will be described later, when the cylinder unit 4 finishes operating and enters a non-operating state, control oil f returned from the damping valve unit 10 flows into the oil chamber 20a, narrowing the air chamber 20c and pushing back the control piston 21 together with the control piston rod 22.

In this specification, "the control piston rod 22 protrudes or retracts" refers to the change in length of the control cylinder unit 19 becoming longer or shorter in the length direction of the control piston rod 22, as the control piston 21 reciprocates and the control piston rod 22 is pulled out in a direction protruding outward from the cylinder case 20 or pushed in in a direction retracting inward.

An operating part 24 is provided at the tip 18b of the transmission member 18, and a passive part 25, with which the operating part 24 can be freely engaged and disengaged, is provided at the protruding tip of the other end of the control piston rod 22 of the pair of control cylinder units 19 on both sides of the transmission member 18.

As shown in Figure 5, the pair of control cylinder units 19, 19 are installed so that their control piston rods 22, 22 protrude in opposite directions, and so that the operating portion 24 of the transmission member 18 is located between their passive portions 25, 25 in the extension/retraction stroke direction of the piston rod 9.

Furthermore, when the piston rod 9 of the cylinder unit 4 is in a neutral position in the direction of extension and retraction stroke (in other words, when the cylinder unit 4 is in its initial, non-operating state), and the air chamber 20c is narrowed and the extension stroke of the control piston rods 22 is positioned at its initial position of "0," the passive parts 25, 25 of these control cylinder units 19, 19 are spaced apart from the operating part 24 by a distance equal to the predetermined extension and retraction stroke set for the piston rod 9.

The predetermined extension/retraction stroke amount refers to the extension stroke amount S and retraction stroke amount S that are set equal in the extension stroke direction and retraction stroke direction, respectively, based on the neutral position N of the piston rod 9, as shown in Figure 5.

In other words, the actuating part 24 and each of the passive parts 25, 25 are equally spaced apart by a distance equal to the predetermined stroke amount S of the piston rod 9.

When the piston rod 9 extends or retracts within the specified stroke amount S, the operating portion 24 of the transmission member 18 moves accordingly, but the operating portion 24 does not engage with the passive portion 25 of any of the control cylinder units 19, and the control cylinder units 19 are not operated.

When the piston rod 9 experiences an excessive extension stroke, such as an excessive extension stroke, that exceeds the predetermined extension/retraction stroke amount S, the actuating portion 24 engages with the passive portion 25 of the control piston rod 22 of one of the control cylinder units 19.

The passive part 25 then causes the control piston rod 22 to protrude by an excess protrusion stroke amount that exceeds the specified protrusion/retraction stroke amount S.

The control piston rod 22 is extended, causing the control piston 21 to slide, and control oil f is discharged from the inlet/outlet port P4 of the cylinder case 20 for the excess extension stroke.

When the piston rod 9, which repeats its extending and retracting strokes, transitions to its retracting stroke, the actuating portion 24 of the transmission member 18 disengages from the passive portion 25, which engaged with the piston rod 22 to cause it to extend.

If the excess protrusion stroke amount during the next protrusion stroke does not exceed the previous excess protrusion stroke amount, the control piston rod 22 that had been protruding during that time will remain in the same position and no control oil f will be discharged. However, if the excess protrusion stroke amount exceeds the previous excess protrusion stroke, the operating part 24 will again engage with the passive part 25, causing the control piston rod 22 to protrude again by the newly increased excess protrusion stroke amount, resulting in the control cylinder unit 19 discharging control oil f in an amount corresponding to the increased excess protrusion stroke.

When an excessive retraction stroke that exceeds the specified extension/retraction stroke amount S occurs in the piston rod 9, the operating part 24 of the transmission member 18 causes the control piston rod 22 of the other control cylinder unit 19 to extend in the same manner as the control piston rod 22 of the one control cylinder unit 19 described above, and control oil f equal to the excess retraction stroke, and also equal to the increase in the excess retraction stroke, is discharged from the inlet/outlet port P4 of the cylinder case 20.

In this way, when the extension/retraction stroke amount of the piston rod 9 of the cylinder unit 4 exceeds the predetermined extension/retraction stroke amount S, the control cylinder unit 19 first discharges control oil f for the excess extension/retraction stroke amount when it exceeds the predetermined extension/retraction stroke amount S, and then repeats this process of discharging control oil f for the excess extension/retraction stroke amount that exceeds the previous excess extension/retraction stroke amount.

In other words, when the pair of control cylinder units 19, 19 exceeds the predetermined extension/retraction stroke amount S, and thereafter, each time the excess extension/retraction stroke amount increases, an increased amount of control oil f is discharged.

As shown in Figure 5, a control oil supply system 26 is provided between the pair of control cylinder units 19, 19 and the damping valve unit 10.

The control oil supply system 26 is composed of a piping system and has a communication section 27 that connects the inlet/outlet ports P4, P4 of a pair of control cylinder units 19, 19, and also connects the communication section 27 to the inlet port P3 of the damping valve unit 10.

The control oil supply system 26 is provided with a control valve unit 30 (see Figure 8) equipped with a check valve 28 and a fluid control valve 100, and is positioned between the communication portion 27 and the inlet port P3 of the damping valve unit 10.

The check valve 28 allows control oil f to flow from the communication portion 27 toward the inlet port P3 and prevents backflow (see arrow p in Figure 8).

Then, control oil f flows into the valve body 13 from the inlet port P3, generating hydraulic pressure on the back surface of the spring seat 15, which acts as back pressure on the check valve 28.

Unlike the valve element 14, the spring seat 15 is provided in a liquid-tight manner and is freely movable relative to the valve body 13.

As a result, the control oil f that flows in from the inlet port P3 presses and displaces the spring seat 15, remaining inside the valve body 13. As a result, the control oil f does not mix with the hydraulic oil F and flow from the hydraulic oil outlet port P2 into the hydraulic oil reservoir 6.

In other words, in the control oil supply system 26 equipped with the check valve 28, the control oil f discharged from each of the inlet/outlet ports P4, P4 flows back and forth between these pairs of inlet/outlet ports P4, P4, and also flows through the check valve 28 and the inlet port P3 to the back surface of the spring seat 15 in the damping valve unit 10, generating oil pressure at the back surface of the spring seat 15 that changes the spring force of the pressure regulating spring 16.

The piston rod 9 of the cylinder unit 4 alternately extends and retracts, causing the control piston rods 22, 22 of the pair of control cylinder units 19, 19 to alternately extend, causing control oil f to be intermittently discharged alternately from each inlet/outlet port P4, P4.

The check valve 28 introduces control oil f into the inlet/outlet port P3 when the oil pressure of the control oil f discharged from the inlet/outlet port P4 of one of the control cylinder units 19 during the protruding operation and acting through the communication part 27 exceeds the valve opening pressure. On the other hand, when the oil pressure of the control oil f is below the valve opening pressure, the check valve 28 prevents the control oil f from flowing into the inlet port P3.

The control oil f, whose flow is blocked by the check valve 28, flows through the communication section 27 into the inlet/outlet port P4 of the other control cylinder unit 19 (where no hydraulic pressure is generated in the oil chamber 20a and the control piston rod 22 can move toward the air chamber 20c).

This communication section 27 functions as a relief circuit when the control oil f cannot pass through the check valve 28, such as when the hydraulic pressure generated behind the spring seat 15 (the back pressure of the check valve 28) reaches the set upper limit.

When an excessive extension stroke and an excessive retraction stroke occur, the pair of control cylinder units 19, 19 alternately extend and retract each time the stroke increases. The hydraulic pressure of the control oil f generated by these units repeatedly acts on the check valve 28, and the check valve 28 allows the control oil f to flow into the inlet port P3 of the damping valve unit 10 each time the pressure exceeds the valve opening pressure.

As a result, within the valve body 13 of the damping valve unit 10, the control oil f is introduced from the inlet port P3 to the back surface of the spring seat 15, and the gradually increasing amount of control oil f causes the pressure adjustment spring 16 to gradually contract between itself and the valve body 14. This contraction increases the spring force of the pressure adjustment spring 16 that biases the valve body 14.

In other words, the spring seat 15 is moved so as to compress the pressure adjustment spring 16 by the hydraulic pressure of the control oil f introduced from the inlet port P3, thereby causing the spring force of the pressure adjustment spring 16 to change according to the amount of excess protruding stroke or excess retracting stroke.

As shown in Figure 8, the control oil supply system 26 is provided with a bypass path 29 that bypasses the check valve 28 to return the control oil f to the pair of control cylinder units 19, 19. This bypass path 29 is provided with the above-mentioned fluid control valve 100 in parallel with the check valve 28.

When, for example, an earthquake subsides and the cylinder unit 4 ceases operation and enters a deactivated state (the piston rod 9 returns to the neutral position N in the extension/retraction stroke direction), this fluid control valve 100 utilizes the fluid pressure flowing in from the first port as described above to sequentially return the control oil f sent to the damping valve unit 10 from the inlet port P3 via the communication portion 27 to the inlet/outlet ports P4, P4 of the pair of control cylinder units 19, 19 (see arrow q in Figure 8).

Furthermore, while the cylinder unit 4 is operating, the fluid control valve 100 allows the control oil f blocked by the check valve 28 to be bypassed (see arrow r in Figure 8).

In this oil damper system 1, for example, as described above, when an earthquake subsides and the cylinder unit 4 ceases operation, becoming inactive and the flow of hydraulic oil F that moves the valve body 14 ceases, the damping valve unit 10 is provided with return means for returning the control oil F from the damping valve unit 10 to the inlet/outlet ports P4, P4 of each control cylinder unit 19, 19, in order to return each control piston rod 22, 22 to its initial position with a protruding stroke of "0."

In the example of the damping valve unit 10 shown in Figure 6, the return means is configured so that the pressure regulating spring 16 is set to a spring force that presses the spring seat 15 so that the control oil f flows out into the control oil supply system 26.

In other words, when the cylinder unit 4 transitions from an operating state to a non-operating state, only a slight hydraulic pressure acts on the valve body 14 of the damping valve unit 10 at the hydraulic oil inlet port P1, which is connected to the hydraulic oil outlet chamber R1, and the operating portion 24 does not engage with the passive portion 25 to cause the control piston rod 22 to protrude.

At this time, as the pressure regulating spring 16 expands from its contracted state due to the control oil f via the spring seat 15 and returns to its original state, it presses against the spring seat 15 to block the inlet port P3, and pushes almost all of the control oil f from the valve body 13 back through the fluid control valve 100 (arrow q) to the control oil supply system 26 and, ultimately, to the inlet/outlet port P4 of each control cylinder unit 19, 19.

When hydraulic oil F is flowing, the valve body 14 compresses the pressure regulating spring 16, increasing the reaction force on the spring seat 15 and creating a strong force pushing back the control oil F.

However, the pressure-receiving portion 103g of the spool 103 is pressed strongly, reaching the first end wall 105a, and the movable passage 103d is at its narrowest.

As a result, the amount of control oil f that returns to the second flow path body 106 during the time it takes for the earthquake to subside (1 to 2 minutes) is extremely small.

It is desirable that the spring force of the pressure regulating spring 16 be such that even when the cylinder unit 4 is in an inoperative state and the flow of hydraulic oil F has ceased, the control oil F gradually flows out and is returned to the control oil supply system 26 via the fluid control valve 100.

At this time, in the fluid control valve 100, the movable passage 103d is slightly wider than when hydraulic oil F is flowing.

The pressure adjustment spring 16 should be installed so that the valve body 14 can close the hydraulic oil inlet port P1 and the spring seat 15 can close the introduction port P3, and so that no or only a small deformation load is applied to the pressure adjustment spring 16.

In Figure 5, reference numeral 31 denotes a hydraulic pressure gauge that displays the hydraulic pressure within the control oil supply system 26, and reference numeral 32 denotes an on-off valve for draining the control oil f provided in the control valve unit 30.

To explain the operation of the oil damper system 1, the cylinder unit 4 is set between the ground 2 and the building 3 with the piston rod 9 in the neutral position N in the extension/retraction stroke direction.

For example, when an earthquake occurs and the cylinder unit 4 begins to operate, if the piston rod 9 does not have an excessive protruding stroke or excessive retracting stroke, the pair of control cylinder units 19, 19 will not be operated, and the cylinder unit 4 will absorb earthquake energy by opening and closing the valve body 14 of the damping valve unit 10 in response to the outflow pressure of the hydraulic oil F with the initial spring characteristics set in the pressure regulating spring 16.

When the piston rod 9 experiences an excess extension/retraction stroke amount exceeding the predetermined extension/retraction stroke amount S, the control cylinder units 19, 19 are actuated by the actuating portion 24 of the transmission member 18.

When the control piston rod 22 of one of the control cylinder units 19 is extended by either the initial excessive extension stroke or excessive retraction stroke, and control oil F is introduced from the inlet/outlet port P4 through the check valve 28 to the back surface of the spring seat 15 of the damping valve unit 10, the pressure regulating spring 16 is compressed. As a result, the damping valve unit 10 opens and closes the valve body 14 against the outflow pressure of the hydraulic oil F due to the spring characteristics of the pressure regulating spring 16, which have been changed to a spring force greater than the initial spring characteristics, thereby increasing the absorption of earthquake energy.

When the excess extension/retraction stroke is within the initial excess extension/retraction stroke amount and does not exceed that amount, the pair of control piston rods 19, 19 are not further extended by the transmission member 18.

On the other hand, whenever an excess protruding stroke or excess retracting stroke occurs that exceeds the previous excess protruding/retracting stroke, the check valve 28 is opened by the hydraulic pressure of the control oil f discharged from each of the pair of control cylinder units 19, 19, and each time this occurs, the control oil f is introduced into the damping valve unit 10, causing the spring force of the pressure regulating spring 16 to change increasingly significantly.

Therefore, the greater the extension/retraction stroke of the piston rod 9 caused by an earthquake, the greater the spring force of the pressure regulating spring 16 of the damping valve unit 10 can be, resulting in a significant change in energy absorption performance.

Afterwards, for example, when the earthquake subsides and the cylinder unit 4 ceases operation and enters a non-operating state (the piston rod 9 returns to the neutral position N in the extending/retracting stroke direction), the movable passage 103d widens slightly, causing the pressure adjustment spring 16, which had been in a compressed state in the damping valve unit 10, to expand with the valve body 14 as its base point, slightly facilitating its elastic recovery. This presses the spring seat 15 toward the inlet port P3, allowing the control oil f introduced into the valve body 13 to gradually return to the control oil supply system 26.

In the control oil supply system 26, control oil f flows from the bypass path 29 through the fluid control valve 100 in the direction of arrow q.

In the fluid control valve 100, while the fluid pressure of the control oil f flowing out from the inlet port P3 is high, this fluid pressure moves the spool 103 toward the second port 108, compressing the coil spring 104 and narrowing the movable passage 103d, thereby restricting the flow of control oil f flowing through this narrowed movable passage 103d.

Then, as the fluid pressure decreases, the spool 103 is pushed back by the elastic force of the coil spring 104, widening the movable passage 103d, and almost the entire amount of control oil f flows smoothly from the inlet port P3 side through this widened movable passage 103d and out through the second port 108.

The control oil f flowing out of the fluid control valve 100 flows into the communication section 27 and is then returned to the oil chambers 20a, 20a through the inlet/outlet ports P4, P4 of each control cylinder unit 19, 19. This causes the control pistons 21, 21 to slide to narrow the air chambers 20c, 20c, and the control cylinder rods 22, 22 are retracted into the cylinder cases 20, 20, returning the control cylinder units 19, 19 to their initial state.

In this oil damper system 1, when the flow of hydraulic oil F that moves the valve body 14 ceases, the damping valve unit 10 is provided with a return means configured as a pressure regulating spring 16 that returns the control oil f to each of the control cylinder units 19, 19 in order to return each of the control piston rods 22, 22 to their initial positions. Therefore, there are no locations where foreign matter such as dust can get mixed into the control oil f between the control cylinder unit 19 and the control oil supply system 26, where the control oil f flows, preventing premature deterioration of the control oil f.

When the biasing force of the pressure regulating spring 16 is high, the movable passage 103d is narrowed, so the control oil f returns slowly over time (high damping performance is maintained at least until the earthquake subsides) to the control cylinder units 19, 19. As the biasing force of the pressure regulating spring 16 decreases, the movable passage 103d widens, allowing all of the control oil f to return to the control cylinder units 19, 19.

In addition, the spring force of the coil spring 104 can be increased or decreased by increasing or decreasing the amount of screwing of the screw member 109 and changing the position of the spool 103. Therefore, by adjusting the relationship between the biasing force of the pressure adjustment spring 16 and the degree of opening of the movable passage 103d, the time it takes for the control oil f to return to the control cylinder units 19, 19 can be adjusted.

In addition, by providing the damping valve unit 10 with the return means as the pressure adjustment spring 16, maintenance work related to the spring characteristics for adjusting performance can be performed on the damping valve unit 10 alone.

This improves the maintainability of the oil damper system 1.

The control oil supply system 26 is provided with a bypass path 29 that bypasses the check valve 28. The bypass path 29 is provided with a fluid control valve 100 in parallel with the check valve 28, which sequentially returns control oil f from the inlet port P3 of the damping valve unit 10 to the inlet/outlet ports P4, P4 of the pair of control cylinder units 19, 19 via the communication section 27. This allows the cylinder unit 4 and the pair of control cylinder units 19, 19 to smoothly return to their pre-operation neutral state after an earthquake has subsided, for example.

100 Fluid control valve 101 Flow path 102 Flow path member 103 Spool 103d Movable path 103f Flow path 103g Horizontal path 104 Coil spring 105 First flow path body 105c First path portion 105f Communication path 106 Second flow path body 106b Second path portion 107 First port 108 Second port 109 Screw member

Claims (3)

A fluid control valve that is provided in a flow path and allows a fluid to flow in one direction and restricts the flow of a fluid in the opposite direction,
a flow path member having a first port and a second port connected to the flow path at both ends and provided with a passage portion through which a fluid flows;
a spool having a flow passage communicating with the first port through which a fluid flows, the spool being provided in the passage portion so as to be slidable back and forth between the first port and the second port;
a spring provided in the passage portion and elastically biasing the spool from the second port side toward the first port side;
a communication passage provided in the flow path member for communicating the passage portion with the flow path;
a movable passage provided on the spool so as to communicate with the communication passage, the range of communication with the communication passage being changed by sliding movement of the spool in a reciprocating direction;
a fluid control valve characterized in that the range of communication between the movable passage and the communication passage widens when the spool is slidably moved toward the first port by the elastic bias of the spring, and the range of communication between the movable passage and the communication passage narrows so as to restrict the flow of fluid when the spool is slidably moved toward the second port against the elastic bias of the spring by fluid pressure of fluid acting on the spool from the first port side. The fluid control valve described in claim 1, characterized in that the first port is provided with a spring force adjustment means that adjusts the spring force of the spring by changing the position of the spool that is elastically biased by the spring. A fluid control valve as described in claim 1 or 2, characterized in that a pressure-receiving portion on which the fluid pressure of the fluid acts is formed in the flow passage of the spool.