JP5831979B2 - Hydraulic circuit and damper - Google Patents

Description

  The present invention relates to a hydraulic circuit and a damper, and more particularly to an improvement of a hydraulic circuit and a damper suitable for use in a seismic isolation device and a vibration control device that suppress vibrations of structures and large machines.

  The seismic isolation device is equipped with a support device such as a ball isolator or rubber interposed between the ground and the structure, and supports the structure so that it can be displaced relative to the ground, and transmits seismic motion to the structure. It is designed to be insulated. In addition to the support device as described above, this seismic isolation device includes a damper interposed between the ground and the structure, and the vibration of the structure is attenuated by the damping force generated by the damper. It is made to suppress the vibration of a structure.

  On the other hand, the vibration damping device is configured by, for example, a damper interposed between a structure column and a beam, or between an upper layer beam and a lower layer beam. The deformation is suppressed to suppress the vibration of the structure.

  In a damper used for such a seismic isolation device or damping device, it is preferable to exhibit a large damping force for large vibrations and a small damping force for small vibrations.

  This is because if the damper exerts a large damping force against small vibrations, the damper's damping force may be excessive and cause the structure to vibrate with the damping force. May end up. Further, when the damping force of the damper is too small for large vibrations, there arises a problem that the vibration of the structure cannot be sufficiently suppressed.

  In order to cope with such a problem, there is a damper that uses a solenoid valve to make the damping force variable. For example, it is preferable to make the damping force variable even when power cannot be secured due to a power failure or the like. In some cases, it is desirable to adopt a structure that can make the damping force variable. Therefore, in the conventional damper, in order to make the damping force mechanically variable according to the stroke amount, a bypass path is formed on the side of the damper body, and an opening / closing valve for opening and closing the bypass path is provided. (For example, refer to Patent Document 1).

  The damper includes a housing that is provided on the side of the damper main body and in which the bypass path is formed, and a spool that is partially inserted into the housing and protrudes from the housing at both ends. This spool is parallel to the damper body, and one end of the spool is connected to a vibration control target to which the damper body is attached. When the damper body expands and contracts, the spool is displaced with respect to the housing. Opens and closes the bypass.

JP 2006-161842 A

  However, since the above-described damper forms a damping force adjusting portion by a housing that forms a bypass path on the side of the damper body and a spool that protrudes outward from the housing in parallel to the damper body, this damping force The spool, which is a part of the adjustment unit, is exposed outside the damper body, and there is a risk of deformation due to contact with an object, and the variable position of the damping force can be adjusted if the damper is not installed on the vibration suppression target. There is a problem that complicated work is required during installation.

  Therefore, the present invention was devised to improve the above-mentioned problems, and the object of the present invention is to make the damping force of the damper variable so that the damping force adjusting unit does not interfere with the outside. It is to provide a hydraulic circuit and a damper that do not require complicated work at the time of installation.

In order to achieve the above object, the hydraulic circuit in the first problem solving means of the present invention includes a damper main body that discharges liquid from the inside along with expansion and contraction, and a tank that absorbs liquid discharged from the damper main body. In the hydraulic circuit provided between the damper body and the tank, a damping valve that is provided in the middle of the discharge passage and that provides resistance to the flow of the liquid that passes through, and the discharge passage. A sub-discharge passage arranged in parallel, a sub-damping valve that is provided in the middle of the sub-discharge passage and provides resistance to the flow of liquid passing therethrough, a valve body that opens and closes the sub-discharge passage, and a back surface side of the valve body It is in communication with the logic valve and a back pressure chamber in communication with the above tank, and the back pressure chamber and the tank by utilizing the pressure in the damper body when the pressure is equal to or greater than the predetermined pressure in the damper body Breaker breaker With the door, the blocking mechanism comprises a shut-off valve for opening and closing the control passage provided in the middle of a control passage communicating the said back pressure chamber and said tank, applying a pressure in the damper body to the shut-off valve And a sequence valve that is provided in the middle of the pilot passage and opens the pilot passage when the pressure in the damper body exceeds a predetermined pressure, and the shut-off valve is a valve that opens and closes the control passage. A main body and an elastic body that urges the valve body in a direction to open the control passage, and resists the urging force of the elastic body when the valve body receives pressure in the damper main body through the pilot passage. Thus, the control passage is blocked .

In order to achieve the above-described object, the hydraulic circuit in the second problem solving means of the present invention absorbs the liquid discharged from the damper main body and the damper main body that discharges the liquid from the inside along with expansion and contraction. In a hydraulic circuit provided between the tank and the tank, a discharge passage communicating the damper main body and the tank , a damping valve provided in the middle of the discharge passage to provide resistance to the flow of the liquid, and the discharge A sub-discharge passage arranged in parallel with the passage; a sub-damping valve provided in the middle of the sub-discharge passage to provide resistance to the flow of liquid; a valve body that opens and closes the sub-discharge passage; and a back side of the valve body a logic valve and a back pressure chamber which is provided on and communicates to the tank, and the back pressure chamber and the tank by utilizing the pressure in the damper body when the pressure is equal to or greater than the predetermined pressure in the damper body Disconnect And a disconnection mechanism, the blocking mechanism comprises a shut-off valve for opening and closing the control passage provided in the middle of a control passage communicating the said back pressure chamber and the tank, the pressure in the damper body to the shut-off valve And a sequence valve that is provided in the middle of the pilot passage and opens the pilot passage when the pressure in the damper main body exceeds a predetermined pressure. The valve opening pressure of the sequence valve It is characterized by being higher than the valve opening pressure .

A damper equipped with a hydraulic circuit and a hydraulic circuit can make the damping force variable by utilizing the pressure in the damper body, and the hydraulic circuit that is the damping force adjusting unit can be accommodated in the damper. The circuit can adjust the damping force independently without cooperating with members outside the damper.

  According to the hydraulic circuit and the damper of the present invention, the damping force of the damper can be made variable, the hydraulic circuit as a damping force adjusting unit does not interfere with the outside, and no complicated work is required when installing the damper. It will end.

It is a circuit diagram showing a hydraulic circuit and a damper in one embodiment. It is sectional drawing of the damper in one embodiment. It is a characteristic view explaining the damping characteristic of the damper in one embodiment.

The present invention will be described below based on the illustrated embodiment. As shown in FIG. 1, the hydraulic circuit C according to the embodiment includes a damper body D that discharges liquid from the inside along with expansion and contraction, and a tank T that absorbs liquid discharged from the damper body D. Is provided. The hydraulic circuit C includes a discharge passage 1 that connects the damper main body D and the tank T, a damping valve 2 that is provided in the middle of the discharge passage 1 and that provides resistance to the flow of liquid that passes therethrough, and a discharge passage 1. A sub-discharge passage 3 arranged in parallel with each other, a sub-damping valve 4 provided in the middle of the sub-discharge passage 3 to provide resistance to the flow of liquid passing therethrough, a logic valve 5 that opens and closes the sub-discharge passage 3, and a blocking mechanism 6 And is configured.

  The hydraulic circuit C, the damper body D, and the tank T constitute a damper. Although the damper is not illustrated, for example, an elastic body such as a ball isolator or a laminated rubber is provided between the ground and the structure. Intervened to function as part of the seismic isolation device, or intervened between the pillars and beams of the structure or between the upper and lower beams to function as a part of the vibration control device However, the use of the hydraulic circuit C and the damper is not limited to this.

  Further, in this embodiment, the damper main body D includes a cylinder 11, a piston 12 slidably inserted into the cylinder 11, and one end connected to the piston 11, as shown in FIGS. 1 and 2. A rod 13 that is movably inserted into the cylinder 11 and a piston chamber P and a rod chamber R partitioned by a piston 12 in the cylinder 11 are configured. The damper body D is provided with a suction passage 14 that allows only a liquid flow from the tank T to the piston chamber P, and a rectifying passage 15 that allows only a liquid flow from the piston chamber P to the rod chamber R. The discharge passage 1 in the hydraulic circuit C communicates the rod chamber R and the tank T described above.

  An outer cylinder 20 that covers the cylinder 11 is provided on the outer peripheral side of the cylinder 11, and a tank T is formed by an annular gap between the cylinder 11 and the outer cylinder 20. The left ends of the cylinder 11 and the outer cylinder 20 in FIG. 2 are closed by a rod guide 21 through which the rod 13 is inserted. Further, the right end of the cylinder 11 in FIG. 2 is closed by a bottom member 22, and the right end of the outer cylinder 20 in FIG. 2 is closed by a lid 23. The cylinder 11 is housed and fixed in the outer cylinder 20 by being sandwiched by the rod guide 21 and the lid 23 which are fixed to both ends of the outer cylinder 20 together with the bottom member 22. Further, a valve block 24 is detachably attached to the side of the rod guide 21, and a hydraulic circuit C is provided in the valve block 24.

  Further, in this case, the piston chamber P and the rod chamber R are filled with a liquid such as hydraulic oil, and the liquid is also stored in the tank T. Here, the liquid is hydraulic oil, but other liquids may be used, and water, an aqueous solution, or the like may be used if there is no harmful effect such as rust.

  The suction passage 14 is provided with a check valve 14a that allows only the flow of liquid from the tank T to the piston chamber P. The suction passage 14 allows only the flow of liquid from the tank T to the piston chamber P. It is set as a one-way passage. In this embodiment, the suction passage 14 is provided in the bottom member 22 as shown in FIG.

  Similarly, the rectifying passage 15 is provided with a check valve 15a that allows only the flow of liquid from the piston chamber P to the rod chamber R in the middle, and the rectifying passage 15 passes through the rectifying passage 15 from the piston chamber P to the rod chamber R. It is a one-way passage that allows only flow. In the case of this embodiment, the rectifying passage 15 is provided in the piston 12 as shown in FIG.

  The suction passage 14 and the rectification passage 15 can be provided in addition to the above-described members. However, providing these in the damper has an advantage that the damper can be reduced in size. Further, the bottom member 22 and the lid 23 may be configured as a single component, and the suction passage 14 may be provided in the component.

  When the damper body D configured as described above is extended, the volume of the piston chamber P is expanded and the rod chamber R is compressed to reduce the volume, so that the expanded piston chamber P is sucked from the tank T. The liquid supplied through the passage 14 and pushed out from the rod chamber R is discharged to the tank T through the hydraulic circuit C. Further, when the damper main body D contracts, the piston chamber P is compressed and the volume is reduced, and the volume of the rod chamber R is expanded. Therefore, the rectifying passage 15 is connected to the rod chamber R expanding from the compressed piston chamber P. Since the liquid moves through the cylinder 11 and the volume of liquid into which the rod 13 enters the cylinder 11 becomes excessive in the cylinder 11, the excess liquid is discharged to the tank T via the hydraulic circuit C. The That is, the damper of this embodiment is configured as a so-called uniflow type damper in which the liquid flow is always in one direction regardless of whether it is extended or contracted, and is discharged from the cylinder 11 to the tank T. When the liquid passes through the hydraulic circuit C, resistance is given and a damping force is exhibited. In this embodiment, as described above, the tank T not only absorbs the liquid discharged from the cylinder 11 but also supplies the liquid deficient in the cylinder 11 when the damper body D is extended. 11, and a sufficient amount of liquid necessary for the operation of the damper main body D is stored inside.

  In this case, the cross-sectional area of the rod 13 is set to be a half of the cross-sectional area of the piston 12, and if the stroke amount on the expansion side and the contraction side of the damper main body D is the same, even at the time of expansion, However, the same volume of liquid is discharged from the cylinder 11 to the tank T. Therefore, if the liquid column rigidity is ignored, the damper can exhibit the same damping force at the time of expansion and contraction as long as the stroke speeds of the expansion side and contraction side are the same. It is optimal for seismic isolation devices and damping devices that do not want to bias the damping force.

  Next, the hydraulic circuit C will be described in detail. The discharge passage 1 communicates the rod chamber R and the tank T in the damper main body D, and a damping valve 2 is provided in the middle thereof. The damping valve 2 has a valve body 2a for opening and closing the discharge passage 1, a spring 2b for biasing the valve body 2a in a direction to close the discharge passage 1, and a pressure upstream of the damping valve 2 facing the spring 2b. And a pressure introduction path 2c that acts on the valve body 2a in a direction to open the discharge passage 1. Then, when the pressure in the rod chamber R reaches the valve opening pressure with the rod chamber R as the upstream, the damping valve 2 is pressed by the upstream pressure acting on the valve body 2a via the pressure introduction path 2c, and the spring 2b. , The discharge passage 1 is opened, and the discharge passage 1 is a one-way passage that allows only the flow of liquid from the rod chamber R to the tank T. In this example, the damping valve 2 also has a function as a check valve. However, if a check valve is provided separately, the damping valve 2 is a throttle valve or the like that allows bidirectional passage. Also good.

  The sub discharge passage 3 is arranged in parallel with the discharge passage 1 and communicates the rod chamber R and the tank T in the damper main body D. A sub-damping valve 4 is provided in the middle of the sub-discharge passage 3, and the sub-attenuation valve 4 includes a valve body 4 a that opens and closes the sub-discharge passage 3 and the sub-discharge passage 3 in the same manner as the damping valve 2. A spring 4b that biases the valve body 4a in the closing direction, and a pressure introduction path 4c that causes the pressure upstream of the sub damping valve 4 to act on the valve body 4a in a direction to open the sub discharge passage 3 opposite to the spring 4b. It is prepared for. Then, when the pressure in the rod chamber R reaches the valve opening pressure with the rod chamber R as the upstream, the auxiliary damping valve 4 is pressed by the upstream pressure acting on the valve body 4a via the pressure introduction path 4c and springs. By compressing 4b, the sub-discharge passage 3 is opened, and the sub-discharge passage 3 is a one-way passage that allows only the flow of liquid from the rod chamber R to the tank T. In this example, the auxiliary damping valve 4 also has a function as a check valve. However, if a separate check valve is provided, the auxiliary damping valve 4 is bi-directional like the damping valve 2. It may be a throttle valve or the like that allows

  The logic valve 5 includes an annular valve seat 5a provided in the middle of the sub-discharge passage 3, a valve body 5b that opens and closes the valve seat 5a to open and close the sub-discharge passage 3, and a back side of the valve body 5b. A back pressure chamber 5c that is provided and communicates with the tank T via the control passage 7, and a spring 5d that urges the valve body 5b to seat on the valve seat 5a, that is, a direction that closes the auxiliary discharge passage 3. It is prepared for. The valve body 5b is provided with a hole 5e that guides the pressure in the rod chamber R on the upstream side of the valve seat 5a to the back pressure chamber 5c on the back side of the valve body 5b. A diaphragm 5f is provided.

  Subsequently, as the pressure in the damper main body D, in this case, when the pressure in the rod chamber R becomes a predetermined pressure or higher, the shut-off mechanism 6 uses the pressure in the rod chamber R to use the back pressure chamber 5c and the tank T. It has come to break communication with. More specifically, the shut-off mechanism 6 uses the pressure in the damper main body D, which becomes high when the damper main body D expands and contracts. In this case, the damper main body D is set to a uniflow type, In doing so, the pressure in the rod chamber R, which is high, is used as the pressure in the damper body D. When this pressure exceeds a predetermined pressure, the communication between the back pressure chamber 5c and the tank T is cut off.

  Specifically, the shut-off mechanism 6 includes a shut-off valve 8 that is provided in the middle of the control passage 7 that communicates the back pressure chamber 5c and the tank T, and that opens and closes the control passage 7. The shut-off valve 8 is connected to the damper main body. In this case, as the pressure in D, the pilot passage 9 that applies the pressure in the rod chamber R, and the pilot passage 9 that is provided in the middle of the pilot passage 9 and the pressure in the rod chamber R exceeds a predetermined pressure, And a sequence valve 10 to be opened.

  The control passage 7 communicates the back pressure chamber 5c and the tank T as described above, and the shutoff valve 8 and the variable throttle valve O are provided in series in the middle of the control passage 7. The opening and closing of the logic valve 5 can be controlled by opening and closing the control passage 7 with the shutoff valve 8. More specifically, when the shutoff valve 8 opens the control passage 7, the back pressure chamber 5c of the logic valve 5 is in communication with the tank T, and the back pressure chamber 5c is connected to the sub discharge passage 3 through the hole 5e. The pressure in the rod chamber R that is upstream of the logic valve 5 is reduced by the throttle 5f. On the valve body 5b of the logic valve 5, a force in the direction of retreating from the valve seat 5a due to the pressure in the rod chamber R, that is, the force in the direction of separating, acts, whereas the pressure in the back pressure chamber 5c A force in the direction of moving forward to 5a, that is, the direction of sitting, acts. As described above, since the pressure in the rod chamber R is reduced and acts on the back pressure chamber 5c, the force in the direction of separating the valve body 5b from the valve seat 5a is larger, and this force is the spring. When the urging force of 5d is overcome, the valve body 5b is separated from the valve seat 5a and the auxiliary discharge passage 3 is opened. That is, the logic valve 5 opens as the pressure in the damper body D, in this case, when the pressure in the rod chamber R reaches a pressure (opening pressure) that can retract the valve body 5b. . On the other hand, when the control passage 7 is blocked by the shutoff valve 8, the communication between the back pressure chamber 5c and the tank T is cut off, so that the valve body 5b is moved in a direction to compress the back pressure chamber 5c. As a result, the valve body 5b is locked, and the logic valve 5 blocks the auxiliary discharge passage 3. The throttle 5f exhibits the function of adjusting the pressure of the back pressure chamber 5c and the function of setting the valve opening pressure of the logic valve 5, and reduces the pressure of the back pressure chamber 5c more than the pressure on the front side of the valve body 5b. Thus, the logic valve 5 is opened. The variable throttle valve O is provided to adjust the pressure in the back pressure chamber 5c, and the greater the resistance applied to the liquid flow in the variable throttle valve O, the greater the pressure loss in the variable throttle valve O. When the shut-off valve 8 is opened, the pressure in the back pressure chamber 5c increases, so that the opening pressure of the logic valve 5 increases.

  As can be understood from the above, if the control passage 7 is opened by the shut-off valve 8, the logic valve 5 can be opened and the auxiliary discharge passage 3 can be opened. When the shut-off valve 8 is closed, the logic valve 5 is closed. Thus, the sub discharge passage 3 is blocked.

  Next, the shut-off valve 8 is configured as a spring offset two-position switching valve, and shuts off the communication position 8b and the control passage 7 for opening the control passage 7 and bringing the back pressure chamber 5c and the tank T into communication. A valve main body 8a having a position 8c and a spring 8d as an elastic body that urges the valve main body 8a in a direction to open the control passage 7 are provided. The shut-off valve 8 is basically pressed by a spring 8d and takes a communication position 8b. As the elastic body, a member other than the spring 8d can be used as long as the valve body 8a can be urged.

  The pilot passage 9 causes the pressure in the rod chamber R to act on the valve body 8a so as to move the valve body 8a in a direction to block the control passage 7 in opposition to the urging force of the spring 8d. In the middle, a sequence valve 10 for opening and closing the pilot passage 9 is provided.

  In this case, the sequence valve 10 has a valve body 10a that opens and closes the pilot passage 9, a spring 10b that biases the valve body 10a in a direction to close the pilot passage 9, and a pressure upstream of the sequence valve 10 that opposes the spring 10b. And a pressure introduction path 10c that acts on the valve body 10a in a direction in which the pilot passage 9 is opened. When the sequence valve 10 reaches the valve opening pressure at which the pressure in the rod chamber R as the pressure in the damper main body D reaches a predetermined pressure, the upstream pressure acting on the valve body 10a via the pressure introduction path 10c. The pilot passage 9 is opened by being pressed by the spring 10b and compressed by the spring 10b.

  The pilot passage 9 is communicated between the variable throttle valve O and the tank T in the middle of the control passage 7 via the drain passage 16 and communicated with the tank T through the control passage 7. A throttle 17 is provided in the middle of the drain passage 16, and this throttle 17 is provided to apply the pressure in the rod chamber R to the valve body 8 a via the pilot passage 9. The drain passage 16 may be communicated with the tank T independently of the control passage 7.

  When the pressure in the rod chamber R of the damper main body D does not reach the valve opening pressure of the sequence valve 10, the sequence valve 10 blocks the pilot passage 9, and the valve main body 8 a of the cutoff valve 8 passes through the pilot passage 9. Since the pressure in the rod chamber R does not act, the shut-off valve 8 is urged by the spring 8d to adopt the communication position 8b, and the logic valve 5 is sub-discharged when the pressure in the upstream rod chamber R reaches the valve opening pressure. The passage 3 is opened. On the other hand, when the pressure in the rod chamber R reaches the valve opening pressure of the sequence valve 10 due to the increase in the pressure in the rod chamber R accompanying the expansion and contraction of the damper main body D, the sequence valve 10 opens the pilot passage 9. The Then, the pressure of the rod chamber R acts on the valve main body 8a of the shutoff valve 8 through the pilot passage 9, the shutoff valve 8 is switched to the shutoff position 8c, and the valve body 5b of the logic valve 5 is locked and the secondary discharge is performed. The passage 3 is blocked.

  In this hydraulic circuit C, a relief passage 18 is provided for communicating the rod chamber R of the damper main body D and the tank T, and the pressure in the rod chamber R is in the middle of the relief passage 18. A relief valve 19 is provided that opens the relief passage 18 to allow the liquid in the damper main body D to escape to the tank T when a preset set pressure is reached. As described above, the relief valve 19 allows the liquid to escape from the damper main body D even when the volume of the liquid increases due to the temperature rise, in addition to allowing the liquid to escape to the tank T when the pressure in the damper main body D becomes excessive. It can also serve as a temperature compensation function to escape to T.

  Next, the operation of the hydraulic circuit C and the damper will be described. As described above, when the damper main body D of the damper is expanded and contracted by an external force, the liquid is pushed out from the cylinder 11 and is discharged to the tank T through the hydraulic circuit C.

  When the expansion / contraction speed of the damper main body D is low and the pressure in the rod chamber R does not reach the valve opening pressure of the sequence valve 10, the sequence valve 10 is closed and the pilot passage 9 is shut off. When the pilot passage 9 is in a blocked state, the shut-off valve 8 takes the communication position 8b and the control passage 7 connects the back pressure chamber 5c to the tank T as described above. In this state, when the pressure in the rod chamber R, which is the pressure upstream of the logic valve 5 in the sub discharge passage 3, reaches the valve opening pressure of the logic valve 5, the logic valve 5 is opened and the sub discharge passage 3 is opened. Open.

  Therefore, when the expansion / contraction speed of the damper is low, the logic valve 5 is placed in a state where it can be opened. When the expansion / contraction speed of the damper is extremely low and the pressure in the rod chamber R, which is the pressure on the upstream side of the hydraulic circuit C, does not reach the valve opening pressure of the logic valve 5, only the discharge passage 1 is opened, The damper exhibits a damping force according to the resistance applied to the liquid that the damping valve 2 passes. Accordingly, the damping characteristic of the damper when the expansion / contraction speed of the damper is in the extremely low speed region is as shown by the line a in FIG. 3, and the damping coefficient becomes high.

  Next, although the expansion / contraction speed of the damper is low, when the pressure in the rod chamber R reaches the valve opening pressure of the logic valve 5, the sub-discharge passage 3 is also opened so that the liquid is not only the discharge passage 1 but also the sub-discharge passage. 3 to move to the tank T. In this case, the damper exhibits a damping force in accordance with the resistance given to the liquid that the damping valve 2 and the sub damping valve 4 pass, and therefore the damping coefficient of the damper when the expansion / contraction speed of the damper is in the low speed range is shown in FIG. As indicated by the middle line b, it is lower than when the logic valve 5 is closed.

  On the other hand, when the expansion / contraction speed of the damper increases and the pressure in the rod chamber R reaches the valve opening pressure of the sequence valve 10, the sequence valve 10 is opened and the pilot passage 9 is opened to shut off. The pressure in the rod chamber R acts on the valve body 8a of the valve 8 to switch the shut-off valve 8 to the shut-off position 8c, and the control passage 7 is shut off.

Then, since the valve body 5b of the logic valve 5 is locked and the auxiliary discharge passage 3 is blocked, only the discharge passage 1 is opened, and the damper has a damping force according to the resistance applied to the liquid that the damping valve 2 passes. To demonstrate. Therefore, the damper damping characteristic when the expansion / contraction speed of the damper is in the high speed range is as shown by a line c in FIG. 3, and the damping coefficient is higher than that in the state in which the logic valve 5 is opened. When the expansion / contraction speed of the damper becomes very high and the pressure in the damper body D reaches the set pressure, which is the valve opening pressure of the relief valve 19, the relief valve 19 is opened and the pressure is reduced to the tank T. because escape into, as shown by line d in FIG. 3, the damping characteristic of the damper when the stretching rate is in the high s speed range, a characteristic as attenuation coefficient is again reduced by the opening of the relief valve 19.

  When a valve opening pressure is set for the damping valve 2, the intercept can be given to the line a, and the damper can generate a damping force even when the expansion / contraction speed of the damper is zero. Further, by making the opening pressure of the logic valve 5 very small, not only the damping valve 2 but also the auxiliary damping valve 4 is opened even when the expansion / contraction speed of the damper is in an extremely low speed range, and the liquid is discharged into the discharge passage 1. In addition, it is possible to pass through the auxiliary discharge passage 3 as well, and it is also possible to realize an attenuation characteristic having a low attenuation coefficient from an extremely low speed region.

  As described above, in the damper according to the present embodiment, the damping coefficient can be made variable according to the expansion / contraction speed of the damper, and a low damping force is exerted for vibration with a small acceleration, and the acceleration is large. Since it can exhibit a high damping force against vibration, it is suitable for suppressing the vibration of structures against seismic motion and is optimal for the use of seismic isolation devices and vibration control devices.

  In the damper described above, the shutoff valve 8 automatically switches between the communication position 8b and the shutoff position 8c depending on the expansion / contraction speed of the damper, so that the damping coefficient in the damper is automatically dependent on the expansion / contraction speed. Can be switched. When the shut-off valve 8 is switched to the shut-off position 8c, the shut-off valve 8 may be provided with a valve position holding mechanism such as a detent mechanism that holds the shut-off position 8c. When the expansion / contraction speed reaches the high speed range and the shutoff valve 8 is switched to the shutoff position 8c and the logic valve 5 is locked in the shutoff state, the damping coefficient is kept high. In this case, in order to unlock the logic valve 5, a lever connected to the valve body 8a of the shut-off valve 8 may be provided and returned to the communication position 8b by operating the lever.

  As described above, the hydraulic circuit C and the damper can change the damping force by using the pressure in the damper body, and the hydraulic circuit C as the damping force adjusting unit can be accommodated in the damper. Therefore, according to the hydraulic circuit C and the damper of the present invention, the hydraulic circuit C as a damping force adjusting unit automatically adjusts the damping force of the damper independently without cooperating with a member outside the damper. Therefore, the hydraulic circuit C does not interfere with members outside the damper, and it is not necessary to align the position according to the mounting position between the hydraulic circuit C and the member provided outside the damper. No complicated work is required at the time of installation to attach to the use location.

  Further, the shut-off mechanism 6 is provided in the middle of the control passage 7 communicating the back pressure chamber 5c and the tank T, and acts on the shut-off valve 8 to apply the pressure in the damper main body D to the shut-off valve 8. And a sequence valve 10 that is provided in the middle of the pilot passage 9 and opens the pilot passage 9 when the pressure in the damper main body D exceeds a predetermined pressure. The shut-off valve 8 opens and closes the control passage 7. A valve body 8a and an elastic body 8d that urges the valve body 8a in a direction to open the control passage 7 are provided. When the valve body 8a receives pressure in the damper body D through the pilot passage 9, the elastic body 8d Since the control passage 7 is blocked against the urging force, the opening / closing control by the hydraulic pressure of the logic valve 5 that receives a large pressure can be realized with a simple circuit configuration, which is excellent in economy.

  Furthermore, by providing the variable throttle valve O in the middle of the control passage 7, the valve opening pressure of the logic valve 5 can be easily tuned, and the damping characteristics of the damper can be adjusted very easily.

  Furthermore, since the hydraulic circuit C is provided in the valve block 24, it is possible to replace the hydraulic circuit C by exchanging the valve block 24, and there is an advantage that maintenance and repair of the damper are simplified.

  In the present embodiment, in order to explain the change in the damping characteristics, the expansion / contraction speed of the damper is provided with sections such as extremely low speed, low speed, high speed, and high speed. It can be set arbitrarily. Specifically, the speed that determines the boundary between the extremely low speed and the low speed can be set by the valve opening pressure of the logic valve 5, and the speed that determines the boundary between the low speed and the high speed is set by the valve opening pressure of the sequence valve 10. The speed that determines the boundary between the high speed and the high speed can be set by the valve opening pressure of the relief valve 19. Therefore, the damping characteristic of the damper described above is an example, and it is natural that the damping characteristic can be set arbitrarily.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

DESCRIPTION OF SYMBOLS 1 Discharge passage 2 Damping valve 3 Sub discharge passage 4 Sub damping valve 5 Logic valve 5b Valve body 5c Back pressure chamber 6 Shut-off mechanism 7 Control passage 8 Shut-off valve 8a Valve body 8d Spring 9 as elastic body Pilot passage 10 Sequence valve 11 Cylinder 12 Piston 13 Rod 14 Suction passage 15 Rectification passage C Hydraulic circuit D Damper body O Variable throttle valve P Piston chamber R Rod chamber T Tank

Claims (6)

In a hydraulic circuit provided between a damper main body that discharges liquid from the inside along with expansion and contraction and a tank that absorbs liquid discharged from the damper main body, a discharge passage that communicates the damper main body and the tank; A damping valve that provides resistance to the flow of liquid that passes through the discharge passage, a sub-discharge passage that is arranged in parallel with the discharge passage, and a flow of liquid that passes through the sub-discharge passage. A pressure reducing valve that provides resistance; a logic valve that has a valve body that opens and closes the auxiliary discharge passage; a back pressure chamber that is provided on the back side of the valve body and communicates with the tank; and pressure in the damper body There utilizing pressure of the damper body when the predetermined pressure or more and a breaking mechanism for breaking the communication between the back pressure chamber and said tank,
The shut-off mechanism is provided in the middle of a control passage communicating the back pressure chamber and the tank, and includes a shut-off valve that opens and closes the control passage, and a pilot passage that applies pressure in the damper body to the shut-off valve. A sequence valve that is provided in the middle of the pilot passage and opens the pilot passage when the pressure in the damper body exceeds a predetermined pressure,
The shut-off valve includes a valve body that opens and closes the control passage, and an elastic body that urges the valve body in a direction to open the control passage. The valve body is disposed in the damper body via the pilot passage. A hydraulic circuit characterized in that when the pressure is received, the control passage is blocked against the urging force of the elastic body . In a hydraulic circuit provided between a damper main body that discharges liquid from the inside along with expansion and contraction and a tank that absorbs liquid discharged from the damper main body, a discharge passage that communicates the damper main body and the tank; A damping valve that provides resistance to the flow of liquid that passes through the discharge passage, a sub-discharge passage that is arranged in parallel with the discharge passage, and a flow of liquid that passes through the sub-discharge passage. A pressure reducing valve that provides resistance; a logic valve that has a valve body that opens and closes the auxiliary discharge passage; a back pressure chamber that is provided on the back side of the valve body and communicates with the tank; and pressure in the damper body Including a blocking mechanism that cuts off the communication between the back pressure chamber and the tank using the pressure in the damper body when the pressure exceeds a predetermined pressure,
The shut-off mechanism is provided in the middle of a control passage communicating the back pressure chamber and the tank, and includes a shut-off valve that opens and closes the control passage, and a pilot passage that applies pressure in the damper body to the shut-off valve. A sequence valve that is provided in the middle of the pilot passage and opens the pilot passage when the pressure in the damper body exceeds a predetermined pressure,
Hydraulic circuit valve opening pressure of the sequence valve is you being greater than the valve opening pressure of the damping valve. The shut-off valve includes a valve body that opens and closes the control passage, and an elastic body that urges the valve body in a direction to open the control passage. The valve body is disposed in the damper body via the pilot passage. 3. The hydraulic circuit according to claim 2, wherein when the pressure is received, the control passage is blocked against an urging force of the elastic body . The hydraulic circuit according to any one of claims 1 to 3, wherein a variable throttle valve is provided in the middle of the control passage. A cylinder, a piston slidably inserted into the cylinder, a rod having one end connected to the piston and movably inserted into the cylinder, and a piston chamber partitioned by the piston in the cylinder; A damper body with a rod chamber, a tank,
A suction passage that allows only the flow of liquid from the tank toward the piston chamber;
A rectifying passage that allows only the flow of liquid from the piston chamber toward the rod chamber;
The hydraulic circuit according to any one of claims 1 to 4 provided between the damper main body and the tank,
The discharge passage communicates the rod chamber and the tank,
A damper in the damper main body referred to in the hydraulic circuit is a pressure in the rod chamber . 6. The damper according to claim 5, wherein the hydraulic circuit is provided in a valve block fixed to a rod guide that closes one end of a cylinder.

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