JP2006010015A - Fluid pressure circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid pressure circuit capable of changing a damping characteristic.
In a fluid pressure circuit C connected to a stretchable body 1, a main damping force generating element 25 provided in a main flow path 10 connecting the stretchable body 1 and a reservoir tank T, the stretchable body 1 and the reservoir tank T are provided. And at least one sub-flow path 11 connected to the on-off valve 40 and the sub damping force generating element 26 provided in the sub-flow path 11, and the on-off valve 40 is energized from one end side. The pilot flow path 42 is connected to the other end side for guiding the pressure on the upstream side of the on-off valve 40 as a pilot pressure.
[Selection] Figure 1

Description

  The present invention relates to a fluid pressure circuit, and more particularly to an improvement of a fluid pressure circuit suitable for a telescopic body applied to a seismic isolation device or a large-sized device.

  In recent years, some seismic isolation devices, for example, have a telescopic body such as a ball isolator in parallel with a telescopic body such as a hydraulic cylinder. At this time, the telescopic body is connected to the telescopic body to control expansion and contraction of the telescopic body. The fluid pressure circuit, which is a circuit, has a lock valve for locking the expansion / contraction body. Specifically, the lock valve is closed in a normal state so that the expansion / contraction body cannot be expanded / contracted, so-called locked state. During an earthquake, the lock valve is opened to expand and contract the expansion body to generate a damping force (see, for example, Patent Document 1).

Therefore, in the above-mentioned seismic isolation device, during normal times, the telescopic body is kept in a locked state to prevent the building from vibrating due to wind or the like, and in the event of an earthquake, the telescopic body can be expanded and contracted to provide a seismic isolation mechanism. It prevents the building from being destroyed by the operation of, and terminates the vibration of the building at an early stage by the damping force generated by the stretchable body.
JP-A-11-201221 (page 3, right column, lines 33 to 45, page 4, left column, lines 1 to 14; lines 29 to 33) 1 and 2)

  However, although the above-described fluid pressure circuit is suitable for a seismic isolation device or the like, it may be pointed out that there are the following problems.

  That is, in the above-described fluid pressure circuit, when the expansion / contraction body is maintained in an expandable / contractible state, the expansion / contraction body has a damping force commensurate with the pressure loss generated when the hydraulic oil passes through the restriction provided in the lock valve. Since they are generated, only the same damping characteristics can always be generated regardless of the magnitude of the earthquake or vibration.

  On the other hand, particularly in seismic isolation devices, in recent years, it has been preferable to reduce the generated damping force of a telescopic body for weak earthquakes and increase the generated damping force for somewhat large earthquakes. For example, it is desired that the damping characteristic of the damping force generated by the expansion / contraction body approximates a so-called square characteristic.

  Accordingly, the present invention has been made to improve the above-mentioned problems, and an object of the present invention is to provide a fluid pressure circuit capable of changing the damping characteristic.

  In order to achieve the above-described object, the problem-solving means of the present invention includes a main damping force generating element provided in a main flow path connecting the expansion and contraction body and the reservoir tank in the fluid pressure circuit connected to the expansion and contraction body, In the relief flow path connecting the expansion / contraction body and the reservoir tank, at least one or more sub flow paths connecting the expansion / contraction body and the reservoir tank, the on-off valve and the sub damping force generating element provided in the sub flow path The on-off valve is urged from one end side to be set to a normally open type, and the pressure on the upstream side of the on-off valve in the sub-flow path is set as the pilot pressure on the other end side. A pilot flow path for guiding is connected.

  According to the present invention, the damping characteristic of the damping force generated by the stretchable body can be automatically switched without special control.

  Also, there is no need to switch the on-off valve using, for example, an electrical method, and the on-off valve is opened and closed based on the pressure and displacement using a sensor for detecting the pressure in the telescopic body or the like, or a sensor for detecting the displacement. Therefore, it is not necessary to perform special control such as controlling the fluid pressure, so that the manufacturing cost of the fluid pressure circuit is low, and there is no risk of malfunction of the on-off valve.

  The present invention will be described below based on the illustrated embodiment. FIG. 1 is a circuit diagram showing a fluid pressure circuit in an embodiment. FIG. 2 is a schematic view showing a state in which a building is equipped with a seismic isolation device to which a fluid pressure circuit is applied. FIG. 3 is a diagram illustrating a damping characteristic in a stretchable body to which a fluid pressure circuit according to an embodiment is applied.

  As shown in FIG. 1, the fluid pressure circuit C in one embodiment is connected to a hydraulic cylinder 1 that is a stretchable body. And this cylinder 1 is interposed so that it may become parallel between the ground G and the building A, as shown in FIG. The ball isolator B is interposed, and the cylinder 1, the fluid pressure circuit C, and the ball isolator B constitute a seismic isolation device.

  Although the seismic isolation device, as shown, employs a ball isolator B to roll and support the building A with respect to the ground G, it can support the building A without impairing the seismic isolation function. As long as it is possible, other known bearing members used in this type of seismic isolation device may be adopted. Specifically, for example, instead of the ball isolator B, the building A is replaced with a flexible bearing member such as laminated rubber. You may support.

  In this embodiment, the fluid pressure circuit C is embodied in the seismic isolation device, but the fluid pressure circuit of the present invention can be applied to other devices besides the seismic isolation device. Needless to say.

  In addition, the cylinder 1 as an expansion / contraction body includes a cylinder body 2, a piston 3 that is slidably inserted into the cylinder body 2, and a rod 4 that is coupled to the piston 3. The piston 3 is divided into two oil chambers R1 and R2, and the oil chambers R1 and R2 are filled with hydraulic fluid as a fluid. Here, the fluid is called hydraulic oil, but other fluids may be used, and water may be used if there is no harmful effect such as rust.

  Further, the oil chambers R1 and R2 are communicated with each other through a pipe line 5. In the middle of the pipe line 5, hydraulic oil is allowed to move from the oil chamber R1 to the oil chamber R2, and the oil chamber R2 to the oil chamber. A check valve 6 is provided to prevent the hydraulic oil from moving to R1, and the cylinder 1 is a so-called uniflow type cylinder.

  In the present embodiment, the expansion / contraction body is the hydraulic cylinder 1, but any expansion and contraction may be used as long as the fluid enters and exits, so there are no problems such as strength when applied to seismic isolation devices and other devices. For example, in addition to the cylinder, a container that can be expanded and contracted by entering and exiting the fluid may be used.

  Subsequently, the fluid pressure circuit C basically includes a damping valve 25, which is a main damping force generating element provided in the main flow path 10 connecting the oil chamber R2 of the cylinder 1 and the reservoir tank T, and the oil of the cylinder 1. The on-off valve 40 and the damping valve 26, which is a sub damping force generating element, provided in the sub channel 11 connecting the chamber R2 and the reservoir tank T, and the relief channel connecting the oil chamber R2 of the cylinder 1 and the reservoir tank T. And a relief valve 30 provided in the middle 12.

  In the following, the main flow path 10 is connected to the main flow path 10 by branching the sub flow path 11 between the cylinder 1 and the damping valve 25, and the main flow path 10 and the sub flow path 11 are connected to the cylinder 1. And the reservoir tank T are arranged in parallel.

  Further, the oil chamber R1 of the cylinder 1 and the reservoir tank T are connected by a pipe line 14. In the middle of the pipe line 14, the hydraulic oil is allowed to move from the reservoir tank T to the oil chamber R1, and the oil is discharged. A check valve 7 is provided to prevent the hydraulic oil from moving from the chamber R1 to the reservoir tank T.

  Accordingly, the hydraulic oil in the oil chamber R2 can be discharged to the reservoir tank T by the main flow path 10 or the sub flow path 11, and can be supplied from the reservoir tank T when the hydraulic oil is insufficient in the oil chamber R1. In addition, when the hydraulic oil becomes excessive, the hydraulic fluid moves to the oil chamber R2 via the pipe line 5. Therefore, the cylinder 1 can expand and contract in a state where the main flow path 10 and the sub flow path 11 are communicated.

  The damping valve 25 provided in the main channel 10 is a damping force variable valve that changes the channel area using the upstream side hydraulic pressure of the channel 10 as a pilot pressure, and the channel increases as the upstream hydraulic pressure increases. The area is set so as to increase, and the damping valve 26 provided in the sub-flow path 11 has the same configuration as the damping valve 25.

  Therefore, the damping valve 25 and the damping valve 26 are arranged in parallel to the cylinder 1. Basically, when the on-off valve 40 described later is opened, the cylinder 1 is configured by both the damping valves 25 and 26. In the state where the damping force is generated and the on-off valve 40 is closed, the damping force is generated only by the damping valve 25.

  The damping characteristics of the damping valve 25 and the damping valve 26 do not need to be the same, and can be arbitrarily set so as to be optimal for the cylinder 1 that is a telescopic body to which the fluid pressure circuit C is applied. Good.

  The on-off valve 40 includes a communication position 41 for opening the sub-channel 11, a blocking position 42 for blocking the sub-channel 11, a biasing spring S provided on one end side, and a sub-channel 11 on the other end side. The pilot flow path 43 guides the pressure upstream from the on-off valve 40 as a pilot pressure, and is normally opened to be urged by the urging spring S to take the communication position 41 until the pilot pressure reaches a predetermined value. Set to type.

  On the other hand, when the pilot pressure supplied from the pilot flow path 43 reaches a predetermined value, the on-off valve 40 is switched to close the sub flow path 11.

  In the case of this seismic isolation device, for example, if the seismic isolation device is set to a pressure value when the earthquake reaches a certain magnitude, the on-off valve 40 is maintained open when the earthquake is weak. The cylinder 1 generates a damping force not only by the damping valve 25 but also by the damping valve 26. When the earthquake becomes a certain magnitude, the opening / closing valve 40 is switched to the closed state, and the cylinder 1 is only driven by the damping valve 25. A damping force will be generated.

  Therefore, in this fluid pressure circuit C, when the pressure upstream of the on-off valve 40 of the sub-flow path 11 reaches a predetermined value, the damping characteristic in the cylinder 1 as the expansion / contraction body is automatically switched without performing special control. Will be.

  That is, there is no need to switch the on-off valve 40 using, for example, an electrical method such as a solenoid, and the pressure using the sensor for detecting the pressure in the cylinder 1 or the like, the sensor for detecting the displacement of the cylinder 1, etc. Since it is not necessary to perform special control such as controlling the opening / closing of the on-off valve based on the displacement, the manufacturing cost of the fluid pressure circuit C is low, and there is no risk of malfunction of the on-off valve 40.

  Further, since the on-off valve 40 is switched by the pilot pressure, its responsiveness is good, and there is an advantage that switching of the damping characteristic is performed quickly.

  At this time, when not only the damping valve 25 but also the damping valve 26 functions, the flow path area increases accordingly, so that the damping characteristic of the cylinder 1 is as shown by the straight line X in FIG. Since the damping force generated with respect to the expansion / contraction speed of the cylinder 1 is relatively low and only the damping valve 25 functions when the on-off valve 40 is closed, the damping characteristic of the cylinder 1 is a straight line in FIG. As shown in Y.

  That is, the damping characteristic in the cylinder 1 as the expansion / contraction body is approximated to a so-called square characteristic, and this allows the fluid pressure circuit C to generate the damping force optimum for the seismic isolation device in the cylinder 1. is there.

  In addition, although it is the setting method of the said predetermined value, throttling is further provided in the middle of the pilot flow path 43 by the change of the pressure receiving area which receives the initial load of the urging | biasing spring S, or the pilot pressure in the valve body of the on-off valve 40. The switching point of the attenuation characteristic, that is, the position of the point V in FIG. 3 may be set so as to be optimal for the apparatus and equipment to which the cylinder 1 is applied.

  Further, in the present embodiment, a passage 44 leading to the downstream side of the on-off valve 40 of the sub-flow path 11 is provided on one end side where the biasing spring S of the on-off valve 40 is provided. In this case, the passage 44 may be connected to the reservoir tank T. In this case, the pressure on the downstream side of the on-off valve 40 is provided. It is also possible to perform the function of adjusting the setting of the predetermined value by positively loading the valve on one end side of the on-off valve 40.

  In turn, a relief flow channel 12 is connected upstream of the branch point of the main flow channel 10 with the sub flow channel 11, that is, on the cylinder 1 side, and further between the relief flow channel 12 and the sub flow channel 11. Is provided with a locking mechanism 20.

  The lock mechanism 20 includes a lock valve 21 and a switching valve 22 that controls opening and closing of the lock valve 21. Specifically, the lock valve 21 has a poppet 21 a that is a valve body, and the poppet 21 a is urged and seated on a valve seat 21 d formed in the flow path 10.

  The poppet 21a is provided with a passage 21b for guiding the hydraulic pressure upstream of the valve seat 21d to the back side of the poppet 21a, and a throttle 21c is provided in the middle of the passage 21b. Further, the hydraulic oil passing through the back side of the poppet 21 a, that is, the right end surface side in FIG. 1, is discharged to the reservoir tank T via the midway switching valve 22.

  On the other hand, the switching valve 22 is configured as a spring-offset electromagnetic two-position switching valve, and when it is not energized, the switching valve 22 prevents the hydraulic oil from moving toward the reservoir tank T and allows the movement in the opposite direction. And a communication position 22b that allows hydraulic oil to pass through when energized.

  When the switching valve 22 takes the shut-off position 22a, the hydraulic oil passing through the back side of the poppet 21a is not discharged to the reservoir tank T. Therefore, the poppet 21a cannot be separated from the valve seat 21d, and the lock valve 21 On the contrary, when the communication position 22b is adopted, the hydraulic oil passing through the back side of the poppet 21a is discharged to the reservoir tank T. Therefore, the throttle 21c causes the front and back sides of the poppet 21a to A pressure difference is generated between them, and thereby the poppet 21a moves backward, that is, moves to the right in FIG. 1, and the lock valve 21 is opened.

  That is, the opening and closing of the lock valve 21 is controlled by controlling the acting force (in this case, oil pressure) acting on the back surface of the poppet 21a, which is the valve body, and the acting force is controlled by the switching valve 22. Will be.

  Therefore, when the lock valve 21 is closed, the hydraulic oil in the oil chamber R2 of the cylinder 1 is prevented from flowing into the reservoir tank T, so that the cylinder 1 is brought into a non-extensible state, that is, a so-called locked state. Will be maintained.

  In the present embodiment, the lock valve 21 has the poppet 21a, but the valve body may be a spool instead.

  In this seismic isolation device, the cylinder 1 is maintained in an expandable / contractible state from the normal time so that the seismic isolation effect can be expressed from the early stage of the earthquake even when a sudden earthquake occurs. Control is applied to the locking mechanism 20 that is optimal for the building A, such as when the building A is locked. However, when vibration due to an earthquake acts on the building A, it is basically locked. The valve 21 is opened, and when the cylinder 1 expands and contracts in this state, the switching valve 40 performs the switching operation according to the expansion / contraction speed, so that the damping characteristic as described above is exhibited.

  In addition, although the operation | movement at the time of the expansion / contraction operation | movement of the cylinder 1 is as above, the relief valve 30 is provided in the middle of the relief flow path 12, and this relief valve 30 is a thing of a conventionally well-known structure. . The relief valve 30 is opened when the relief flow path 12 reaches a predetermined cracking pressure so that hydraulic oil can be discharged to the reservoir tank T.

  That is, when an external force that expands and contracts the cylinder 1 at normal times acts and the pressure in the cylinder 1 increases abnormally, for example, when the building A vibrates due to a very large earthquake, the relief valve 30 opens. Thus, assuming that the damping characteristic of the cylinder 1 is shown by a straight line Z in FIG. 3, the damping force generated by the cylinder 1 is not increased.

  Therefore, the opening operation of the relief valve 30 can prevent the building A from being destroyed without giving a large stress that causes plastic deformation to the pillars and beams of the building A.

  In addition, when the fluid pressure circuit C fails for some reason, for example, when the lock mechanism 20, the on-off valve 40, the damping valves 25, 26, etc. cannot function due to contamination, the relief valve 30 opens and the cylinder is opened. 1 can be allowed to expand and contract, and damage or rupture of the fluid pressure circuit C and thus the cylinder 1 can be prevented.

  The above-described lock mechanism 20 can be realized only by providing the above-described switching valve 22 in the middle of the flow path 10 when only the expansion / contraction control of the cylinder 1 is considered. 1 is applied to a seismic isolation device as in the present embodiment, or is applied to a large-scale device in which a large load or the like is applied, the flow rate increases. Since the entire switching valve including the size is increased and the fluid pressure circuit becomes larger as a result, the switching valve 22 is controlled to open / close the lock valve 21 and the entire fluid pressure circuit can be downsized. In this embodiment, since the large hydraulic pressure does not act on the switching valve 22, the suction force of the solenoid required for the switching operation can be small. There is also advantage that in consideration for the power saving that must generate a Do suction force.

  Furthermore, since the lock mechanism 20 having the above-described configuration is employed, it is possible to allow a large amount of flow to pass as compared with the case where the lock valve 21 is controlled to be opened and closed electromagnetically. There is nothing. That is, when the lock valve 21 is electromagnetic, the valve body may not be moved by the suction force of the solenoid because the hydraulic pressure acts on the valve body when the flow rate increases. 21 does not have a large hydraulic pressure, and the valve body of the lock valve 21 is driven by the hydraulic pressure, so that there is no problem that may occur electromagnetically.

  Incidentally, in the above description, one sub flow path 11 including the on-off valve 40 and the damping valve 26 is provided. However, a plurality of parallel flow paths 11 are provided in parallel between the main flow path 10 and the reservoir tank T. It may be possible to finely change the attenuation characteristic.

  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.

It is a circuit diagram which shows the fluid pressure circuit in one embodiment. It is the schematic which shows the state with which the seismic isolation apparatus to which the fluid pressure circuit was applied was equipped in the building. It is a figure which shows the damping characteristic in the expansion-contraction body to which the fluid pressure circuit in one embodiment is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder 2 which is expansion-contraction body Cylinder main body 3 Piston 4 Rod 5, 14 Pipe line 6, 7 Check valve 10 Main flow path 11 Sub flow path 12 Relief flow path 20 Lock mechanism 21 Lock valve 21a Poppet 21b, 44 which is valve body 21c , 43 Restriction 21d Valve seat 22 Switching valve 22a, 42 Shut-off position 22b, 41 Communication position 25 Damping valve 26 as main damping force generating element Damping valve 30 as sub damping force generating element 30 Relief valve 40 On-off valve 43 Pilot flow path A Building B Ball isolator C Fluid pressure circuit G Ground R1, R2 Oil chamber S Energizing spring T Reservoir tank

Claims (3)

In the fluid pressure circuit connected to the stretchable body, a main damping force generating element provided in a main flow path connecting the stretchable body and the reservoir tank, and at least one sub-flow path connecting the stretchable body and the reservoir tank And an on-off valve and a sub damping force generating element provided in the sub-flow path, and the on-off valve is urged from one end side to be set to a normally open type, and the other end side has a sub-flow path A fluid pressure circuit comprising a pilot flow path for guiding the pressure upstream of the on-off valve as a pilot pressure. The sub-flow path is connected between the expansion body of the main flow path and the main damping force generating element, and a lock mechanism is provided on the upstream side of the sub-flow path of the main flow path to control whether expansion / contraction of the expansion / contraction body is possible. The fluid pressure circuit according to claim 1. The fluid pressure circuit according to claim 1, wherein a relief flow path for connecting the extendable body and the reservoir tank is provided, and a relief valve is provided in the relief flow path.

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