Base isolation device, base isolation system and base isolation method

Abstract

To provide a base isolation device, a base isolation system and a base isolation method capable of quickly isolating movement in a three-dimensional direction.SOLUTION: A base isolation device 1 comprises a frame 2 installed on a foundation F, a target installation part 3 on which a target to be isolated is placed, a hydraulic cylinder 4 installed between the frame 2 and the target installation part 3, and a cylinder mounting part 5 that attaches one end of the hydraulic cylinder 4 to the frame 2 and the other end of the hydraulic cylinder 4 to the target installation part 3, where a parallel link mechanism is formed in which the plurality of hydraulic cylinders 4 is connected in parallel to the frame 2 to suspend the target installation part 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a seismic isolation device, a seismic isolation system, and a seismic isolation method for isolating an object from seismic vibrations. [Background technology]

[0002] Traditionally, earthquake-resistant devices such as laminated rubber or sliding bearings have been installed in the foundations of buildings as a measure to reduce damage caused by large earthquakes. Currently, the mainstream method is used to reduce vibrations in the horizontal direction only. However, recent research has shown that vertical earthquake motions are also a problem as a cause of ceiling collapse or destruction of beam-column joints.

[0003] For example, Patent Document 1 describes a technology that supports buildings and objects with a support device that moves as if the load support point is the end of a long-period pendulum, creating a virtual pendulum and enabling vertical seismic isolation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3646926 Summary of the Invention [Problem to be solved by the invention]

[0005] However, vertical seismic isolation needs to be able to support the enormous load of a building while also being able to move flexibly during an earthquake. However, the technology described in Patent Document 1 is based on virtual pendulum movement, so it takes time to move vertically, and it is not possible to achieve rapid seismic isolation against vertical movement.

[0006] An object of the present invention is to provide a seismic isolation device, a seismic isolation system, and a seismic isolation method that are capable of quickly isolating a structure against movements in three dimensions. [Means for solving the problem]

[0007] The seismic isolation device according to the present invention comprises: A frame to be installed on the foundation; An object placement section for placing an object to be isolated; a fluid pressure cylinder disposed between the frame and the target placement portion; a cylinder mounting portion that mounts one end of the fluid pressure cylinder to the frame and the other end of the fluid pressure cylinder to the target placement portion; Equipped with A parallel link mechanism is configured to suspend the object placement unit by connecting a plurality of the fluid pressure cylinders in parallel to the frame. It is characterized by: Effect of the Invention

[0008] Such a seismic isolation device can quickly isolate a structure from three-dimensional movements. [Brief description of the drawings]

[0009] [Figure 1] 1 is a perspective view of an example of a seismic isolation device according to an embodiment of the present invention; [Diagram 2] 1 is a front view of an example of a seismic isolation device according to an embodiment of the present invention. [Diagram 3] 1 is a plan view of an example of a seismic isolation device according to an embodiment of the present invention; [Figure 4] 3 shows an example of a hydraulic cylinder of the seismic isolation device of the present embodiment. [Diagram 5] An example of the seismic isolation device of this embodiment used in a building is shown. [Figure 6] 1 shows an example of a seismic isolation system according to an embodiment of the present invention. [Figure 7] 4 shows an example of a standby state of the seismic isolation system of the present embodiment. [Figure 8] 3 shows an example of a first preparation state of the seismic isolation system of the present embodiment. [Figure 9] 13 shows an example of a second preparation state of the seismic isolation system of the present embodiment. [Figure 10] 13 shows an example of a third preparation state of the seismic isolation system of the present embodiment. [Figure 11] 11 shows an example of a fourth preparation state of the seismic isolation system of this embodiment. [Figure 12] 1 shows an example of the seismic isolation system of this embodiment when an earthquake occurs. [Figure 13] 1 shows an example of the operation of the seismic isolation system of this embodiment. [Figure 14] 1 shows an example of a flowchart of a seismic isolation method using the seismic isolation system 10 of the present embodiment. [Figure 15] 4 shows an example of the seismic isolation effect of the seismic isolation system of this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings. In the following, the scope necessary for the explanation to achieve the object of the present invention will be shown typically, and the scope necessary for the explanation of the relevant part of the present invention will be mainly explained, and the parts that are omitted will be explained based on known techniques. Note that the seismic isolation device 1 of this embodiment uses a hydraulic cylinder 4 as a fluid pressure cylinder, but the working fluid may be replaced with a non-compressible fluid such as water or emulsion oil with a rust inhibitor dissolved therein.

[0011] Fig. 1 shows a perspective view of an example of a seismic isolation device 1 of this embodiment. Fig. 2 shows a front view of the example of the seismic isolation device 1 of this embodiment. Fig. 3 shows a plan view of the example of the seismic isolation device 1 of this embodiment. For ease of understanding, the mounting column 3b and stage 3c of the target mounting portion 3 are shown by virtual lines (two-dot chain lines) in Fig. 2, and the stage 3c is omitted in Fig. 3.

[0012] The seismic isolation device 1 of this embodiment includes a frame 2 installed on a foundation F, a target mounting section 3 on which a building B as a seismic isolation target is placed, a hydraulic cylinder 4 having one end attached to the frame 2 and the other end attached to the target mounting section 3, and a cylinder mounting section 5 for mounting the hydraulic cylinder 4 to the frame 2 and the target mounting section 3. The seismic isolation device 1 constitutes a parallel link mechanism that suspends the target mounting section 3 by connecting the multiple hydraulic cylinders 4 in parallel to the frame 2.

[0013] The frame 2 is placed on a foundation F and supports a target placement portion 3 via a hydraulic cylinder 4. The foundation F may be a ground or concrete foundation on which a building B as a seismic isolation target is to be placed. The frame 2 has a pedestal 2a formed at its lower end, a support pillar 2b extending upward from the pedestal 2a, and a support portion 2c placed at the upper end of the support pillar 2b. The frame 2 is made of a highly rigid material such as a steel frame or reinforced concrete.

[0014] The base 2a is placed on a foundation F or the like and is a part that supports the entire seismic isolation device 1. In this embodiment, the base 2a viewed from above forms a hexagon with three long sides and three short sides arranged alternately. The base 2a is not limited to a hexagon, and may be any shape such as a polygon, a circle, an ellipse, a sector, or a star. The support pillars 2b extend vertically upward from the base 2a. In this embodiment, the support pillars 2b extend vertically upward in two from each long side of the base 2a, for a total of six pillars. The support portion 2c is installed at the upper end of the support pillars 2b, and one end of the hydraulic cylinder 4 is attached to the support portion 2c. In this embodiment, the support portion 2c viewed from above has the same shape as the base 2a, and forms a hexagon with three long sides and three short sides arranged alternately. The number of hydraulic cylinders 4 is not limited to six, and more than six may be used.

[0015] The target mounting section 3 is suspended from a hydraulic cylinder 4, and a seismic isolation target such as a building B or a large machine is placed on it. The target mounting section 3 of this embodiment has a mounting plate 3a attached to the other end of the hydraulic cylinder 4 via a cylinder mounting section 5, a mounting column 3b extending vertically upward from the mounting plate 3a, and a stage 3c installed on the upper end of the mounting column 3b. Note that the mounting column 3b and the stage 3c do not necessarily have to be installed.

[0016] The cylinder mounting portion 5 mounts the hydraulic cylinder 4 to the frame 2 or the target placement portion 3. The cylinder mounting portion 5 in this embodiment uses a spherical bearing. By using a spherical bearing as the cylinder mounting portion 5, it is possible to smoothly achieve seismic isolation in three dimensions. Note that the cylinder mounting portion 5 is not limited to a spherical bearing, and may have a structure that allows for seismic isolation in three dimensions using a parallel link mechanism, such as a clevis, a clevis and a spherical bearing, a clevis and a rotating seat, a clevis and a trunnion and a clevis, a universal joint, or a connection using a material such as a flexible wire.

[0017] The seismic isolation device 1 of this embodiment uses a hydraulic cylinder 4. For seismic isolation, air springs using rubber membranes are sometimes used, but air springs have low strength and are difficult to make large. In addition, compressed air is used at low pressure because there is a risk of explosion or fire at high pressure. However, in the case of low pressure, an air spring with a large effective cross-sectional area is required to support a large load, which is expensive. Furthermore, a long range of motion is required to absorb earthquake displacement, but it is difficult to manufacture such a structure.

[0018] In contrast, the hydraulic cylinder 4 uses hydraulic oil, which is a non-compressible fluid, so it is easy to increase the pressure, the device can be made smaller, and costs can be reduced. In addition, the range of motion can be increased with inexpensive commercially available products. Furthermore, while the pressure must be kept below 1 MPa in the case of pneumatic pressure to reduce the risk of explosion or fire, there are products with a pressure of 70 MPa in the case of hydraulic pressure, and simply put, the effective cross-sectional area can be reduced to 1 / 70.

[0019] Fig. 4 shows an example of the hydraulic cylinder 4 of the seismic isolation device 1 of this embodiment. Fig. 4(a) shows a case where the hydraulic cylinder 4 is used for tension. Fig. 4(b) shows a case where the hydraulic cylinder 4 is used for compression.

[0020] The hydraulic cylinder 4 has a cylinder tube 41, a piston 42, a packing 43 that fills the gap between the cylinder tube 41 and the piston 42, and a position sensor 44. In the hydraulic cylinder 4 of this embodiment, one end of the cylinder tube 41 is attached to the frame 2 via a cylinder attachment part 5, and the other end of the piston 42 is attached to the target placement part 3 via the cylinder attachment part 5.

[0021] The cylinder tube 41 has a tube body 41a, a pipe connecting portion 41b that connects from the inside of the tube body 41a to a pipe 69 described later, and a tube mounting portion 41c that is attached to one end of the tube body 41a and the cylinder mounting portion 5. The piston 42 has a piston rod 42a, a piston head 42b that is attached to one end of the piston rod 42a, and a rod mounting portion 42c that is attached to the other end of the piston rod 42a.

[0022] The cylinder tube 41 and the piston 42 are connected via a packing 43. The piston rod 42a is formed at the other end of the tube body 41a and passes through a hole 41d in which a first packing 43a is installed. The piston head 42b is installed inside the tube body 41a. A second packing 43b is installed on the outer periphery of the piston head 42b. The first packing 43a and the second packing 43b are used to seal the inside of the tube body 41a.

[0023] The position sensor 44 detects the position of the piston head 42b relative to the tube body 41a. In this embodiment, the position sensor 44 detects whether the piston head 42b is at a predetermined position relative to the center C of the stroke in the tube body 41a. For example, as shown in FIG. 4, a position at a predetermined first distance on one end side from the center C is defined as a first position H, and a position at the first distance on the other end side is defined as a second position L. Also, a position at a predetermined second distance on one end side from the center C is defined as a third position HH, and a position at the second distance on the other end side is defined as a fourth position LL.

[0024] Seismic isolation is broadly divided into active methods that use sensors and drive devices, and passive methods that use long-period springs, dampers, etc. As active methods are expensive, this embodiment employs the passive method. Passive-type seismic isolation reduces earthquake motion by making the natural period of building B when supported by a spring longer than the period of the earthquake motion. Specifically, an accumulator 63 (described later) is connected to the hydraulic cylinder 4 of this embodiment, and the hydraulic cylinder 4 is used as a long-period spring with high output and small restoring force to support the object to be isolated.

[0025] The restoring force is determined by the capacity of the accumulator 63, so theoretically it is better for the accumulator 63 to be larger. However, if the frictional force of the hydraulic cylinder 4 is greater than the restoring force, the building B will not return to its initial position, and there is a concern that it may lose its posture or gradually approach the operating limit of the hydraulic cylinder 4 and come into contact with it, causing excessive vibration. In addition, the hydraulic cylinder 4 cannot support a force perpendicular to the direction of extension and contraction, so a slide guide must be used in conjunction with it. Slide guides are expensive, and when multiple units are used in parallel, it is difficult to align their directions.

[0026] The seismic isolation device 1 of this embodiment does not use a slide guide, but employs a parallel link mechanism. A parallel link mechanism is a mechanism used in flight simulators and the like, and by connecting six hydraulic cylinders 4 in parallel, it is possible to move a supported object with six degrees of freedom. In the seismic isolation device 1 of this embodiment, the six hydraulic cylinders 4 are each connected to an accumulator 63, and are driven like independent springs, and are used as a passive system. In this way, by using the parallel link mechanism, the seismic isolation device 1 of this embodiment does not need to use a vertical slide guide, which is expensive and difficult to set up.

[0027] A typical parallel link mechanism used in a flight simulator or the like is used by applying a load in the direction compressing the hydraulic cylinder 4. However, as shown in Fig. 4(b), if the opposite side to the piston rod 42a is the high-pressure section 4a and it is used so that a compressive force is generated when an external force is applied, the piston rod 42a may buckle, increasing the friction of the packing 43 and causing breakage, which may cause the piston rod 42a to bend.

[0028] As shown in Fig. 4(a), the hydraulic cylinder 4 of this embodiment is used so that the piston rod 42a side is the high pressure part 4a and a pulling force is generated when an external force is applied. By generating a pulling force when an external force is applied to the hydraulic cylinder 4 of this embodiment, the vector of the force applied to the tube mounting part 41c and the rod mounting part 42c becomes a straight line, the packing 43 is always subjected to an average pressure, and it can operate with minimum friction.

[0029] In addition, in the hydraulic cylinder 4 of this embodiment, since the piston rod 42a does not buckle, a lightweight piston rod 42a with a small diameter can be used, the pressure-receiving area of ​​the piston head 42b is increased, and the diameter of the tube main body 41a can be made small, thereby reducing the size of the hydraulic cylinder 4. Furthermore, in the hydraulic cylinder 4 of this embodiment, since the piston rod 42a does not buckle, it can be operated with low friction, and the restorability is increased, allowing for stable operation.

[0030] In addition, in the seismic isolation device 1 of this embodiment, the six hydraulic cylinders 4 form a parallel link mechanism that cooperates to support the seismic isolation target, so expansion and contraction, rotation of the fulcrum, etc. must operate smoothly. By creating a pulling force when an external force is applied, expansion and contraction, rotation of the fulcrum, etc. can be performed smoothly.

[0031] FIG. 5 shows an example in which the seismic isolation device 1 of this embodiment is used in a building B.

[0032] The seismic isolation device 1 of this embodiment is installed between the foundation F and the building B. Moreover, in the example shown in Fig. 5, a horizontal seismic isolation device 7 is installed below the seismic isolation device 1 of this embodiment. That is, the horizontal seismic isolation device 7 is installed on the foundation F, the seismic isolation device 1 is installed on the horizontal seismic isolation device 7, and the building B is placed on the seismic isolation device 1. The frame 2 of the seismic isolation device 1 is supported by the horizontal seismic isolation device 7, and the building B is placed on the target placement portion 3 of the seismic isolation device 1.

[0033] In this way, by supporting the building B on the foundation F using the seismic isolation device 1 and horizontal seismic isolation device 7 of this embodiment, it is possible to achieve higher performance of seismic isolation in three dimensions. Furthermore, by using the horizontal seismic isolation device 7 to perform seismic isolation in the horizontal direction, it is possible to reduce the horizontal input of the seismic isolation device 1, thereby shortening the stroke of the hydraulic cylinder 4 and making the hydraulic cylinder 4 more compact. Note that since the seismic isolation device 1 of this embodiment can perform seismic isolation in the horizontal direction as well as in the vertical direction, it is not necessary to use the horizontal seismic isolation device 7.

[0034] FIG. 6 shows an example of a seismic isolation system 10 of this embodiment.

[0035] The seismic isolation system 10 of this embodiment includes an earthquake information acquisition unit 11 that acquires information on earthquakes, etc., a control unit 12 that controls a hydraulic circuit 6 as a fluid pressure circuit using the earthquake information acquired by the earthquake information acquisition unit 11, a seismic isolation device 1 that isolates a building B from a foundation F, and a hydraulic circuit 6 that adjusts the hydraulic pressure of a hydraulic cylinder 4 of the seismic isolation device 1. In the seismic isolation system 10 of this embodiment, in the preparation stage, the control unit 12 controls the hydraulic circuit 6 to move the hydraulic cylinder 4 to an initial neutral position, and then makes the pressure of the hydraulic cylinder 4 and the pressure of the accumulator 63 the same. When the earthquake information acquisition unit 11 detects an earthquake, the control unit 12 controls the hydraulic circuit 6 to communicate the hydraulic cylinder 4 and the accumulator 63. After the earthquake, as in the preparation stage, the control unit 12 controls the hydraulic circuit 6 to move the hydraulic cylinder 4 to an initial neutral position, and then makes the pressure of the hydraulic cylinder 4 and the pressure of the accumulator 63 the same.

[0036] The earthquake information acquisition unit 11 detects information on the occurrence of an earthquake, and in this embodiment, an acceleration sensor or the like may be used. In the case of an acceleration sensor, it is sufficient to set it to detect earthquake motion in advance, and transmit information on the occurrence of an earthquake to the control unit 12 when it detects earthquake motion. It is also possible to simply transmit vibration information, and the control unit 12 judges whether or not an earthquake has occurred. The earthquake information acquisition unit 11 may also be a communication device for utilizing an emergency earthquake warning, etc. When an emergency earthquake warning is notified, it is sufficient to transmit information on the occurrence of an earthquake to the control unit 12.

[0037] The control unit 12 is composed of a general-purpose or dedicated computer. The computer is, for example, a stationary computer or a portable computer, and is an electronic device of any form. The computer may be a client-type computer, a server-type computer, a cloud-type computer, or an embedded computer called, for example, a control panel, a controller (including a microcomputer, a programmable logic controller, and a sequencer). The computer has a processor and is composed of one or more arithmetic processing devices (such as a CPU (Central Processing Unit), an MPU (Micro-Processing Unit), a DSP (Digital Signal Processor), a GPU (Graphics Processing Unit), and an NPU (Neural Processing Unit)).

[0038] The hydraulic circuit 6 includes a tank 61 for storing hydraulic oil, a pump 62 for pumping out the hydraulic oil, an accumulator 63 for holding the pressure of the hydraulic circuit 6, a main valve 64 installed in a pipe 69 between the hydraulic cylinder 4 and the accumulator 63, a first valve 65 installed in a pipe 69 between the hydraulic cylinder 4 and the pump 62, a first pressure sensor 66 for detecting the pressure in the pipe 69 between the hydraulic cylinder 4, the main valve 64, and the first valve 65, a second valve 67 installed in a pipe 69 between the accumulator 63 and the pump 62, and a second pressure sensor 68 for detecting the pressure in the pipe 69 between the accumulator 63, the main valve 64, and the second valve 67. The hydraulic circuit 6 is connected by the pipe 69.

[0039] The tank 61 may be any container capable of storing hydraulic oil. The pump 62 may be any device capable of pumping hydraulic oil. In the hydraulic circuit 6 of this embodiment, the pump 62 may be small in size because the hydraulic circuit 6 is isolated by the pressure accumulated in the accumulator 63.

[0040] The accumulator 63 is a container divided by a rubber diaphragm, one side is filled with a gas such as nitrogen gas, and the other side contains excess hydraulic oil in the hydraulic circuit 6. When the pressure in the hydraulic circuit 6 decreases, the diaphragm moves downward and the pressurized hydraulic oil is released from the accumulator 63, and when the pressure in the hydraulic circuit 6 increases, the diaphragm moves upward and the pressurized hydraulic oil is accumulated in the accumulator 63.

[0041] The main valve 64 is installed so as to open and close the piping 69 between the hydraulic cylinder 4 and the accumulator 63. In this embodiment, an air-driven valve is used as the main valve 64. Although an air-driven valve takes longer to open and close than a solenoid valve, the effective cross-sectional area of ​​the flow path can be set to be large.

[0042] The first valve 65 is installed so as to open and close the piping 69 between the hydraulic cylinder 4 and the pump 62. In this embodiment, a solenoid valve is used as the first valve 65. The first pressure sensor 66 detects the pressure in the piping 69 between the hydraulic cylinder 4 and the main valve 64 and the first valve 65.

[0043] The second valve 67 is installed so as to open and close a pipe 69 between the accumulator 63 and the pump 62. In this embodiment, a solenoid valve is used as the second valve 67. The second pressure sensor 68 detects the pressure between the accumulator 63, the main valve 64, and the second valve 67.

[0044] The solenoid valves used for the first valve 65 and the second valve 67 have a fast opening and closing speed, but have a small effective cross-sectional area of ​​the flow passage and large pressure loss due to the flow of hydraulic oil in and out, so they are preferably used for the preparatory operation.

[0045] Next, a method of using the seismic isolation system 10 of this embodiment will be described. There are six hydraulic circuits 6 excluding the hydraulic cylinders 4, the tank 61, and the pump 62 since they constitute a parallel link mechanism, but only one or two will be described in the drawings.

[0046] FIG. 7 shows an example of the standby state of the seismic isolation system 10 of this embodiment.

[0047] The standby state of the seismic isolation system 10 of this embodiment is a state before the occurrence of an earthquake. In the standby state, as shown in FIG. 7, the piston head 42b is adjusted to be between a first position H at a first distance on one end side and a second position L at a first distance on the other end side from the position of the center C of the stroke of the piston 42 relative to the cylinder tube 41. Also, in the standby state, the pressure of the pipe 69 between the high pressure section 4a, the main valve 64, and the first valve 65 and the pressure of the pipe 69 between the accumulator 63, the main valve 64, and the second valve 67 are set to be the same or within a predetermined range. That is, the measurement value of the first pressure sensor 66 and the measurement value of the second pressure sensor 68 are adjusted to be the same or within a predetermined range. In the standby state, the main valve 64, the first valve 65, and the second valve 67 are all closed.

[0048] The seismic isolation system 10 of this embodiment needs to be prepared for adjustment to a standby state. For example, when the piston head 42b is not between a first position H at a predetermined first distance on one end side and a second position L at the first distance on the other end side from the position of the center C of the stroke of the piston 42 relative to the cylinder tube 41 of the hydraulic cylinder 4, the first valve 65 of the hydraulic circuit 6 is adjusted to adjust to the standby state.

[0049] In the seismic isolation system 10 of this embodiment, in the standby state, the hydraulic cylinder 4 has high rigidity, and the seismic isolation target can be prevented from moving due to disturbances such as load fluctuations in the building B to be isolated or wind loads.

[0050] In the seismic isolation system 10 of this embodiment, when a seismic isolation target such as building B is supported by springs, if the weight of building B changes due to the number of people, furniture, equipment, etc., the position of the piston head 42b relative to the cylinder tube 41 of the hydraulic cylinder 4 changes, and the position of building B changes. For this reason, in order to maintain the position of building B, it is necessary to eliminate the spring element of the seismic isolation system 10 and perform alignment. Therefore, the seismic isolation system 10 of this embodiment requires the following preparation state.

[0051] FIG. 8 shows an example of the first preparation state of the seismic isolation system 10 of this embodiment.

[0052] As shown in FIG. 8, the first preparation state of the seismic isolation system 10 of this embodiment is a state in which the piston head 42b is farther away from the center C of the stroke of the piston 42 relative to the cylinder tube 41 than the second position L at a first distance on the other end side that is determined in advance. To move the piston 42 from the first preparation state to the standby state, the first valve 65 is operated to connect the pump 62 and the high pressure section 4a, the pump 62 is operated, and the hydraulic oil in the tank 61 flows into the high pressure section 4a on the piston rod 42a side. Then, the piston head 42b moves beyond the second position L to the standby state. At this time, the target placement section 3 and the building B rise. When the position sensor 44 shown in FIG. 4 detects that the piston head 42b has moved to the standby state and to a predetermined position, the first valve 65 is closed.

[0053] FIG. 9 shows an example of the second preparation state of the seismic isolation system 10 of this embodiment.

[0054] As shown in FIG. 9, the second preparation state of the seismic isolation system 10 of this embodiment is a state in which the piston head 42b is farther away from the center C of the stroke of the piston 42 relative to the cylinder tube 41 than the first position H at a predetermined first distance on one end side. To move the piston 42 from the second preparation state to the standby state, the first valve 65 is operated to connect the tank 61 and the high pressure section 4a, and the hydraulic oil in the high pressure section 4a on the piston rod 42a side is discharged to the tank 61. Then, the piston head 42b moves beyond the first position H to the standby state. At this time, the target placement section 3 and the building B move down. When the position sensor 44 shown in FIG. 4 detects that the piston head 42b has moved to the standby state and to a predetermined position, the first valve 65 is closed.

[0055] The seismic isolation system 10 of this embodiment needs to be prepared for adjustment to a standby state. For example, if the main valve 64 is operated when the measured value of the first pressure sensor 66 and the measured value of the second pressure sensor 68 are the same or not within a predetermined range, an impact may occur, so the second valve 67 of the hydraulic circuit 6 is adjusted to be in a standby state. As an example, the "within the predetermined range" refers to a range in which the piston head 42b is held between a third position HH at a second distance on one end side and a fourth position LL at a second distance on the other end side from the position of the center C of the stroke of the piston 42 relative to the cylinder tube 41 when the main valve 64 is operated and the high pressure part 4a of the hydraulic cylinder 4 is connected to the accumulator 63 in the event of an earthquake.

[0056] FIG. 10 shows an example of the seismic isolation system 10 of this embodiment in a third preparation state.

[0057] The third preparation state of the seismic isolation system 10 of this embodiment is a state in which the detection value of the first pressure sensor 66 is higher than the detection value of the second pressure sensor 68. To make the detection values ​​of the first pressure sensor 66 and the second pressure sensor 68 the same or within a predetermined range, the second valve 67 is operated, the pump 62 and the accumulator 63 are connected, the pump 62 is operated, and the hydraulic oil in the tank 61 is caused to flow into the accumulator 63. Then, the measurement value of the second pressure sensor 68 rises, and when the detection values ​​of the first pressure sensor 66 and the second pressure sensor 68 become the same or within a predetermined range, the second valve 67 is closed.

[0058] FIG. 11 shows an example of the fourth preparation state of the seismic isolation system 10 of this embodiment.

[0059] The fourth preparation state of the seismic isolation system 10 of this embodiment is a state in which the detection value of the first pressure sensor 66 is lower than the detection value of the second pressure sensor 68. To make the detection values ​​of the first pressure sensor 66 and the second pressure sensor 68 the same or within a predetermined range, the second valve 67 is operated to connect the tank 61 and the accumulator 63, and the hydraulic oil in the accumulator 63 is discharged into the tank 61. Then, the measurement value of the second pressure sensor 68 decreases, and when the detection values ​​of the first pressure sensor 66 and the second pressure sensor 68 become the same or within a predetermined range, the second valve 67 is closed.

[0060] In this way, the seismic isolation system 10 of this embodiment can quickly respond to the occurrence of an earthquake by transitioning from the first to fourth preparation states to the standby state. The transition from the first to fourth preparation states to the standby state may be performed according to the measurement values ​​of the position sensor 44, the first pressure sensor 66, and the second pressure sensor 68.

[0061] Fig. 12 shows an example of the seismic isolation system 10 of this embodiment when an earthquake occurs. Fig. 13 shows an example of the operation of the seismic isolation system 10 of this embodiment.

[0062] The seismic isolation system 10 of this embodiment is usually in a standby state as shown in Fig. 7. When an earthquake is detected by the earthquake information acquisition unit 11 shown in Fig. 6, the main valve 64 is immediately operated to connect the high pressure part 4a of the hydraulic cylinder 4 to the accumulator 63. In the standby state, the pressures of the high pressure part 4a of the hydraulic cylinder 4 and the accumulator 63 are kept the same or within a predetermined range, so there is almost no movement of hydraulic oil when the high pressure part 4a of the hydraulic cylinder 4 and the accumulator 63 are connected.

[0063] The seismic isolation system 10 of this embodiment uses such a hydraulic circuit 6 to suspend six hydraulic cylinders 4 from the frame 2 to form a parallel link mechanism, and connects the building B, which is the target for seismic isolation, to be placed on the target support section 3. Therefore, the seismic isolation system 10 of this embodiment can support heavy objects with the soft cushion of the long-period spring with low rigidity of the passive method, and can attenuate earthquake motion.

[0064] For example, in the seismic isolation system 10 of this embodiment, when seismic motion α is input to the foundation F, the hydraulic cylinder 4, the accumulator 63, and the hydraulic oil in the piping 69 between them act as a soft spring as a whole, absorbing the vibration β in the hydraulic cylinder 4 and the vibration γ in the accumulator 63, and the seismic isolated vibration δ is transmitted to the building B.

[0065] FIG. 14 shows an example of a flowchart of a seismic isolation method using the seismic isolation system 10 of this embodiment.

[0066] First, in step 1, it is determined whether or not the position of the piston head 42b detected by the position sensor 44 is within a predetermined range (ST1). Note that the determination is not limited to the position of the piston head 42b, and may be made based on the position of the piston 42 relative to the cylinder tube 41.

[0067] In step 1, if the position of the piston head 42b detected by the position sensor 44 is outside a predetermined range, the first valve 65 is operated in step 2 (ST2).

[0068] 8, when the piston head 42b is farther away from the center C of the stroke of the piston 42 relative to the cylinder tube 41 than a second position L at a predetermined first distance on the other end side, the first valve 65 is operated to connect the pump 62 and the high pressure section 4a, and the pump 62 is operated to cause the hydraulic oil in the tank 61 to flow into the high pressure section 4a on the piston rod 42a side. Then, the piston head 42b moves beyond the second position L to a standby state.

[0069] 9, when the piston head 42b is farther away from the center C of the stroke of the piston 42 relative to the cylinder tube 41 than a first position H at a predetermined first distance on one end side, the first valve 65 is operated to connect the tank 61 and the high pressure section 4a, and the hydraulic oil in the high pressure section 4a on the piston rod 42a side is discharged to the tank 61. Then, the piston head 42b moves beyond the first position H to a standby state.

[0070] In step 1, when the position of the piston head 42b detected by the position sensor 44 is within a predetermined range, the first valve 65 is closed in step 3 (ST3). That is, when the piston head 42b moves to the standby state, the first valve 65 is closed.

[0071] Next, in step 4, it is determined whether or not the pressure difference between the hydraulic cylinder 4 and the accumulator 63 is within a predetermined range (ST4). The pressure difference between the hydraulic cylinder 4 and the accumulator 63 may be the difference between the measurement value of the first pressure sensor 66 and the measurement value of the second pressure sensor 68.

[0072] In step 4, if the pressure difference between the hydraulic cylinder 4 and the accumulator 63 is outside the predetermined range, the second valve 67 is operated in step 5 (ST5).

[0073] For example, when the detection value of the first pressure sensor 66 is higher than the detection value of the second pressure sensor 68, the second valve 67 is operated to connect the pump 62 and the accumulator 63, and the pump 62 is operated to cause the hydraulic oil in the tank 61 to flow into the accumulator 63. Then, the measurement value of the second pressure sensor 68 increases, and the difference between the detection values ​​of the first pressure sensor 66 and the second pressure sensor 68 falls within a predetermined range.

[0074] Furthermore, when the detection value of the first pressure sensor 66 is lower than the detection value of the second pressure sensor 68, the second valve 67 is operated to connect the tank 61 and the accumulator 63, and the hydraulic oil in the accumulator 63 is discharged to the tank 61. Then, the measurement value of the second pressure sensor 68 decreases, and the difference between the detection values ​​of the first pressure sensor 66 and the second pressure sensor 68 falls within a predetermined range.

[0075] In step 4, if the pressure difference between the hydraulic cylinder 4 and the accumulator 63 is within a predetermined range, the second valve 67 is closed in step 6 (ST6). That is, if the difference between the detection value of the first pressure sensor 66 and the detection value of the second pressure sensor 68 is within a predetermined range, the second valve 67 is closed.

[0076] Next, in step 7, it is determined whether or not the earthquake information acquisition unit 11 detects vibrations of a predetermined magnitude or more (ST7). Here, the vibrations of a predetermined magnitude or more may be earthquake motions that are to be isolated from seismic activity.

[0077] When the earthquake information acquisition unit 11 detects vibrations of a predetermined magnitude or greater, it activates the main valve 64 (ST8). Then, the hydraulic oil in the hydraulic cylinder 4, the accumulator 63, and the piping 69 between them acts as a soft spring as a whole, and the heavy load can be supported by the soft cushion of the long-period spring with low rigidity of the passive method, thereby attenuating the earthquake motion.

[0078] If the earthquake information acquisition unit 11 does not detect vibrations of a magnitude equal to or greater than a predetermined magnitude, the process returns to step 1, where the preparation state is confirmed and the standby state is maintained.

[0079] Fig. 15 shows an example of the seismic isolation effect of the seismic isolation system 10 of this embodiment. Fig. 14(a) shows the time history of the acceleration in the north-south direction observed at Takatori Station during the Hyogo-ken Nanbu Earthquake (Great Hanshin-Awaji Earthquake), and Fig. 14(b) shows the results of analyzing the acceleration on the seismic isolation device using the linear acceleration method when the natural period is 3 seconds and the damping constant is 20%.

[0080] As shown in Fig. 14(a), the maximum value of the acceleration of the earthquake motion is 605 cm / s2 on one side and 532 cm / s2 on the other side, whereas as shown in Fig. 14(b), the maximum value of the acceleration of the vibration of building B after seismic isolation is 249 cm / s2 on one side and 216 cm / s2 on the other side. Therefore, according to the seismic isolation system 10 of this embodiment, the maximum value of the acceleration of the vibration is reduced by about 60%.

[0081] The performance of the passive seismic isolation device 1 is determined by the natural period and the damping constant. If the natural period of the seismic isolation device 1 is made longer than the main period (0.02 to 1.15 seconds) that causes earthquake damage, passive seismic isolation becomes possible.

[0082] As described above, the seismic isolation device 1 of this embodiment comprises the frame 2 installed on the foundation F, the target mounting section 3 on which the target to be isolated is placed, the hydraulic cylinder 4 installed between the frame 2 and the target mounting section 3, and the cylinder mounting section 5 which mounts one end of the hydraulic cylinder 4 to the frame 2 and the other end of the hydraulic cylinder 4 to the target mounting section 3, and constitutes a parallel link mechanism which suspends the target mounting section 3 by connecting the multiple hydraulic cylinders 4 in parallel to the frame 2. Therefore, the seismic isolation device 1 of this embodiment can provide rapid seismic isolation for movements in three dimensional directions.

[0083] In addition, in the seismic isolation device 1 of this embodiment, the hydraulic cylinder 4 includes a cylinder tube 41 and a piston 42, the cylinder tube 41 has a tube main body 41a and a tube mounting portion 41c attached to the cylinder mounting portion 5 at one end of the tube main body 41a, the piston 42 has a piston rod 42a, a piston head 42b attached to one end of the piston rod 42a, and a rod mounting portion 42c attached to the cylinder mounting portion 5 at the other end of the piston rod 42a, and the piston rod 42a side within the tube main body 41a is the high pressure portion 4a.

[0084] Therefore, in the seismic isolation device 1 of this embodiment, the piston rod 42a side is the high-pressure part 4a, and when an external force is applied, a pulling force is generated, so that the force vectors applied to the tube mounting part 41c and the rod mounting part 42c are aligned, the gasket 43 is always subjected to average pressure, and can operate with minimal friction.

[0085] In addition, in the hydraulic cylinder 4 of this embodiment, since the piston rod 42a does not buckle, a lightweight piston rod 42a with a small diameter can be used, the pressure-receiving area of ​​the piston head 42b is increased, and the diameter of the tube main body 41a can be made small, thereby reducing the size of the hydraulic cylinder 4. Furthermore, in the hydraulic cylinder 4 of this embodiment, since the piston rod 42a does not buckle, it can be operated with low friction, and the restorability is increased, allowing for stable operation.

[0086] In addition, in the seismic isolation device 1 of this embodiment, the six hydraulic cylinders 4 form a parallel link mechanism that cooperates to support the seismic isolation target, so expansion and contraction, rotation of the fulcrum, etc. must operate smoothly. By creating a pulling force when an external force is applied, expansion and contraction, rotation of the fulcrum, etc. can be performed smoothly.

[0087] The seismic isolation system 10 of this embodiment includes the seismic isolation device 1, a hydraulic circuit 6 that supplies and discharges hydraulic oil to the hydraulic cylinder 4, an earthquake information acquisition unit 11 that acquires earthquake information, and a control unit 12 that controls the hydraulic circuit 6 upon detection of vibrations by the earthquake information acquisition unit 11. Therefore, the seismic isolation system 10 of this embodiment is capable of controlling the hydraulic circuit 6 and the hydraulic cylinder 4 upon detection of vibrations by the earthquake information acquisition unit 11.

[0088] In addition, in the seismic isolation system 10 of this embodiment, the hydraulic cylinder 4 has a position sensor 44 that detects the position of the piston head 42b, and the hydraulic circuit 6 has a tank 61 that stores hydraulic oil, a pump 62 that pumps out the hydraulic oil from the tank 61, an accumulator 63 that maintains the pressure in the hydraulic circuit 6, a pipe 69 that communicates between the tank 61, the pump 62, the accumulator 63, and the hydraulic cylinder 4 so that the hydraulic oil can be supplied and discharged, a main valve 64 that opens and closes the pipe 69 between the hydraulic cylinder 4 and the accumulator 63, a first valve 65 installed to open and close the pipe 69 between the hydraulic cylinder 4 and the pump 62, a second valve 67 installed to open and close the pipe 69 between the accumulator 63 and the pump 62, a first pressure sensor 66 that detects the pressure in the pipe 69 between the hydraulic cylinder 4, the main valve 64, and the first valve 65, and a second pressure sensor 68 that detects the pressure between the accumulator 63, the main valve 64, and the second valve 67.

[0089] Furthermore, in the seismic isolation system 10 of this embodiment, when the position sensor 44 detects that the piston head 42b is located outside a predetermined range, the control unit 12 operates the first valve 65 so that the piston head 42b is located within the predetermined range. Therefore, the seismic isolation system 10 of this embodiment can align the building B and maintain its position even if the weight of the building B changes depending on the number of people, furniture, equipment, etc., and the position of the piston head 42b with respect to the cylinder tube 41 of the hydraulic cylinder 4 changes, causing the position of the building B to change.

[0090] Furthermore, in the seismic isolation system 10 of this embodiment, when the control unit 12 detects that the difference between the measurement value of the first pressure sensor 66 and the measurement value of the second pressure sensor 68 is outside a predetermined range, it operates the second valve 67 so that the difference between the measurement value of the first pressure sensor 66 and the measurement value of the second pressure sensor 68 is within the predetermined range. Therefore, in the seismic isolation system 10 of this embodiment, since there is a risk of an impact occurring if the main valve 64 is operated when the difference between the measurement value of the first pressure sensor 66 and the measurement value of the second pressure sensor 68 is not within the predetermined range, it is possible to adjust the second valve 67 of the hydraulic circuit 6 to a standby state and prevent an impact from occurring even if the main valve 64 is operated.

[0091] Furthermore, in the seismic isolation system 10 of this embodiment, when the earthquake information acquisition unit 11 detects vibrations of a predetermined magnitude or greater, the control unit 12 activates the main valve 64. Therefore, the seismic isolation system 10 of this embodiment can support heavy objects with soft cushions of long-period springs with low rigidity of the passive system, and can attenuate earthquake motion.

[0092] The seismic isolation method using the seismic isolation system 10 of this embodiment includes the steps of: determining whether the position of the piston head 42b detected by the position sensor 44 is within a predetermined range; operating the first valve 65 when the position of the piston head 42b detected by the position sensor 44 is not within the predetermined range; determining whether the difference between the measurement value of the first pressure sensor 66 and the measurement value of the second pressure sensor 68 is within a predetermined range; operating the second valve 67 when the difference between the measurement value of the first pressure sensor 66 and the measurement value of the second pressure sensor 68 is not within the predetermined range; determining whether the earthquake information acquisition unit 11 detects vibrations of a predetermined magnitude or more; and operating the main valve 64 when the earthquake information acquisition unit 11 detects vibrations of a predetermined magnitude or more. Therefore, the seismic isolation method using the seismic isolation system 10 of this embodiment can perform rapid seismic isolation against movements in three dimensions.

[0093] It should be noted that the present invention is not limited to the embodiments, and that although many specific details are included for illustrative purposes in the description of the embodiments, those skilled in the art may make various variations and modifications to these details. [Explanation of symbols]

[0094] 1...seismic isolation device, 2...frame, 3...object placement portion, 4...hydraulic cylinder (fluid pressure cylinder), 41...cylinder tube, 41a...tube body, 41c...tube mounting portion, 42...piston, 42a...piston rod, 42b...piston head, 42c...rod mounting portion, 44...position sensor, 5...cylinder mounting portion, 6...hydraulic circuit (fluid pressure circuit), 61...tank, 62...pump, 63...accumulator, 64...main valve, 65...first valve, 66...first pressure sensor, 67...second valve, 68...second pressure sensor, 69...piping, 7...horizontal seismic isolation device 10...seismic isolation system, 11...earthquake information acquisition unit, 12...control unit, F: Foundation, B: Building (earthquake-resistant target)

Claims

1. A frame to be installed on the foundation; An object placement section for placing an object to be isolated; a fluid pressure cylinder disposed between the frame and the target placement portion; a cylinder mounting portion that mounts one end of the fluid pressure cylinder to the frame and the other end of the fluid pressure cylinder to the target placement portion; Equipped with A parallel link mechanism is configured to suspend the object placement unit by connecting a plurality of the fluid pressure cylinders in parallel to the frame. A seismic isolation device characterized by the above.

2. The fluid pressure cylinder includes a cylinder tube and a piston. the cylinder tube has a tube body and a tube attachment portion attached to the cylinder attachment portion at one end of the tube body, the piston includes a piston rod, a piston head attached to one end of the piston rod, and a rod attachment portion attached to the cylinder attachment portion at the other end of the piston rod, The piston rod side of the tube body is a high-pressure portion. The seismic isolation device according to claim 1 .

3. The seismic isolation device according to claim 2 ; a fluid pressure circuit that supplies and discharges a working fluid to the fluid pressure cylinder; an earthquake information acquisition unit that acquires earthquake information; a control unit that controls the fluid pressure circuit in response to the earthquake information acquired by the earthquake information acquisition unit; Equipped A seismic isolation system characterized by:

4. the fluid pressure cylinder has a position sensor that detects a position of the piston head, The fluid pressure circuit includes: A tank for storing the working fluid; a pump for pumping the hydraulic fluid from the tank; an accumulator for maintaining pressure in the hydraulic circuit; a pipe that communicates between the tank, the pump, the accumulator, and the fluid pressure cylinder so as to be able to supply and discharge the working fluid; a main valve that opens and closes the piping between the fluid pressure cylinder and the accumulator; a first valve installed so as to open and close the piping between the fluid pressure cylinder and the pump; a second valve installed to open and close the piping between the accumulator and the pump; a first pressure sensor for detecting a pressure in the piping between the fluid pressure cylinder, the main valve, and the first valve; a second pressure sensor that detects a pressure between the accumulator, the main valve, and the second valve; have The seismic isolation system according to claim 3 .

5. When the position sensor detects that the piston head is positioned outside a predetermined range, the control unit operates the first valve so that the piston head is positioned within the predetermined range. The seismic isolation system according to claim 4 .

6. When the control unit detects that the difference between the measurement value of the first pressure sensor and the measurement value of the second pressure sensor is outside a predetermined range, the control unit operates the second valve so that the difference between the measurement value of the first pressure sensor and the measurement value of the second pressure sensor is within a predetermined range. The seismic isolation system according to claim 4 .

7. The control unit operates the main valve when the earthquake information acquisition unit detects vibrations of a predetermined magnitude or greater. The seismic isolation system according to claim 4 .

8. A seismic isolation method using the seismic isolation system according to claim 4, determining whether the position of the piston head detected by the position sensor is within a predetermined range; operating the first valve when the position of the piston head detected by the position sensor is not within a predetermined range; determining whether a difference between a measurement value of the first pressure sensor and a measurement value of the second pressure sensor is within a predetermined range; operating the second valve when a difference between a measurement value of the first pressure sensor and a measurement value of the second pressure sensor is not within a predetermined range; A step of determining whether the earthquake information acquisition unit has acquired earthquake information of a magnitude equal to or greater than a predetermined magnitude; activating the main valve when the earthquake information acquisition unit acquires earthquake information of a magnitude equal to or greater than a predetermined magnitude; have A seismic isolation method comprising:

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