Damping device

Abstract

To provide a damping device for further reducing the response acceleration of a base isolation structure having fixed restitutive force.SOLUTION: The damping device includes a piston, a cylinder slidably storing the piston and having a first chamber and a second chamber which are filled with fluid, the first chamber being located on one side in the sliding direction of the piston, the second chamber being located on the other side in the sliding direction, a first flow path communicating the first chamber and the second chamber with each other and having a first flow path resistance, a second flow path as a different flow path from the first flow path, communicating the first chamber and the second chamber with each other, and having a second flow path resistance smaller than the first flow path resistance, and a changeover part for changing over the possibility or not of passing the fluid in the second flow path in one or both of a right direction as a direction from the first chamber side to the second chamber side and a left direction as a direction from the second chamber side to the first chamber side, on the basis of a relative position of the piston to the cylinder.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a damping device.

Background Art

[0002] A damping device that attenuates vibrations may be used together with a seismic isolation device or a vibration control device that suppresses vibrations generated in a structure due to an earthquake or wind. The damping device attenuates vibrations generated in the structure by a damping force proportional to the velocity.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, for example, in a structure of a seismic isolation structure having a certain restoring force mainly using a seismic isolation device such as laminated rubber, it may be required to further reduce the response acceleration of the structure. However, a damping device having only a damping force proportional to the velocity has a limit in reducing the response acceleration of the structure.

[0005] An example of the object of the present invention is to further reduce the response acceleration of a structure of a seismic isolation structure having a certain restoring force. Other objects of the present invention will become apparent from the description herein.

Means for Solving the Problems

[0006] One aspect of the present invention is a piston, a cylinder that slidably houses the piston and has a first chamber located on one side in the sliding direction of the piston and a second chamber located on the other side in the sliding direction, and the first chamber and the second chamber in which a fluid is enclosed, A first flow path that communicates the first chamber and the second chamber and has a first flow path resistance, A second flow path that is a flow path different from the first flow path, communicates the first chamber and the second chamber, and has a second flow path resistance smaller than the first flow path resistance, A switching unit that switches whether or not the fluid can pass through the second flow path in one or both of the right direction, which is the direction from the first chamber side to the second chamber side, and the left direction, which is the direction from the second chamber side to the first chamber side, based on the relative position of the piston and the cylinder, A damping device comprising: Taking a predetermined position of the cylinder as viewed from the piston as a reference position, When the cylinder moves in the right direction as viewed from the piston, When the position of the cylinder as viewed from the piston is located on the left side of the reference position, the fluid passes through the first flow path, When the position of the cylinder as viewed from the piston is located on the right side of the reference position, the fluid passes through the second flow path, When the cylinder moves in the left direction as viewed from the piston, When the position of the cylinder as viewed from the piston is located on the right side of the reference position, the fluid passes through the first flow path, When the position of the cylinder as viewed from the piston is located on the left side of the reference position, the fluid passes through the second flow path, It is a damping device.

[0007] Other features of the present invention will be clarified by the description of the specification and drawings described later.

Advantages of the Invention

[0008] According to the above aspect of the present invention, in a structure of a seismic isolation structure having a certain restoring force, the response acceleration of the structure can be further reduced.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

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DETAILED DESCRIPTION OF THE INVENTION

[0010] At least the following matters become clear from the description of this specification and the accompanying drawings.

[0011] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The same or equivalent components, members, etc. shown in each drawing are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate.

[0012] ==This Embodiment== FIG. 1 is an explanatory diagram showing an application example of the damping device 10 of this embodiment.

[0013] <<Definition of Directions, etc.>> First, while referring to FIG. 1, directions and the like in the damping device 10 of this embodiment will be defined.

[0014] As shown in FIG. 1, the horizontal direction of the structure 100 to which the damping device 10 is applied is defined as the "horizontal direction" of the damping device 10. Note that the "horizontal direction" may be referred to as the "left-right direction", and in the line-of-sight direction shown in FIG. 1, the left side toward the damping device 10 may be referred to as the "left direction", and the right side toward the damping device 10 may be referred to as the "right direction". In the damping device 10 of this embodiment, the "left-right direction" is also the sliding direction of the piston 11 described later.

[0015] Also, the vertical direction of the structure 100 to which the damping device 10 is applied is defined as the "vertical direction" of the damping device 10. Note that the "vertical direction" may be referred to as the "up-down direction", the upper side of the damping device 10 may be referred to as the "up direction", and the lower side of the damping device 10 may be referred to as the "down direction".

[0016] Each of the left direction, the right direction, the upward direction, and the downward direction is a direction with a fixed orientation. Also, the left - right direction is not a direction with a fixed orientation and includes both the left direction and the right direction. Similarly, the up - down direction is not a direction with a fixed orientation and includes both the upward direction and the downward direction.

[0017] <<Summary>> <Application Example> As shown in FIG. 1, the structure 100 to which the damping device 10 of this embodiment is applied has an upper structure 1 (for example, a structure above the ground such as a building) and a lower structure 3 (for example, a structure below the ground such as a foundation). An earthquake isolation device 5 is installed between the upper structure 1 and the lower structure 3. In this embodiment, the earthquake isolation device 5 is a laminated rubber. However, the earthquake isolation device 5 may be an earthquake isolation device other than laminated rubber as long as the structure 100 of the earthquake isolation structure has a certain restoring force. The upper structure 1 is supported by the lower structure 3 via the earthquake isolation device 5. Also, the upper structure 1 and the lower structure 3 can move relative to each other via the earthquake isolation device 5.

[0018] In the following description, regarding the relative movement between the upper structure 1 and the lower structure 3, it may be described as the movement of the upper structure 1 as seen from the lower structure 3. That is, as seen from the lower structure 3, the upper structure 1 moves in the right direction or the left direction.

[0019] The application example of the damping device 10 shown in FIG. 1 is merely an example and is not limited to the above - mentioned application example. The damping device 10 may be applied to structures other than the structure 100 (a so - called base - isolated structure) in which the earthquake isolation device 5 is installed in the foundation part. For example, the damping device 10 may be applied to an application example where it is installed together with an earthquake isolation device in the intermediate layer of a structure, that is, a so - called intermediate - layer isolated structure. Also, it is not limited to structures with an earthquake isolation structure and may be applied to structures with a vibration - damping structure. When applied to a structure with a vibration - damping structure, the damping device 10 will be installed between layers.

[0020] The damping device 10 is a device that damps the vibration of the structure 100. The damping device 10 has a so-called oil damper. The oil damper generates a damping force by the resistance of a fluid (here, hydraulic oil) passing through a flow path that communicates two chambers (a first chamber 13 and a second chamber 14, which will be described later) formed in a cylinder. However, the damping device 10 may have a fluid-operated damper other than the oil damper. The damping device 10 is installed between the upper structure 1 and the lower structure 3 and damps the vibrations of the upper structure 1 and the lower structure 3.

[0021] <Restoring force characteristics> FIG. 2 is an explanatory diagram showing an example of the restoring force characteristics of the structure 100 by the damping device 10 of the present embodiment.

[0022] By the way, by using laminated rubber as the seismic isolation device 5 described above, the structure 100 can have a certain restoring force.

[0023] As described above, the damping device 10 of the present embodiment is a device having an oil damper. Here, in a normal oil damper that simply has a flow path in a cylinder, due to the characteristics of viscous damping (linear damping), the damping force can only be obtained in proportion to the velocity. That is, in a normal oil damper, it is difficult to adjust the damping force according to the relative displacement and the direction of relative movement between the upper structure 1 and the lower structure 3. Therefore, even when trying to reduce the response acceleration of the structure by a normal oil damper, there is a limit to the extent to which the response acceleration of the structure can be reduced.

[0024] Therefore, in the damping device 10 of the present embodiment, as will be described later, by combining and operating a plurality of flow paths (a first flow path 20 and a second flow path 30, which will be described later) having different flow path resistances and a member (a switching unit 60) that switches through which flow path the fluid passes, in the structure 100 of a seismic isolation structure having a certain restoring force, the response acceleration of the structure 100 can be further reduced.

[0025] Before explaining the configuration and operation of the damping device 10 of the present embodiment, the restoring force characteristics of the structure 100 by the damping device 10 will be described with reference to FIG. 2.

[0026] In FIG. 2, the horizontal axis represents the relative displacement x between the upper structure 1 and the lower structure 3 of the structure 100 described above. Here, the position where the upper structure 1 and the lower structure 3 are at a predetermined relative position (hereinafter sometimes referred to as the "reference position") is set as the position of 0 on the horizontal axis. Note that the reference position between the upper structure 1 and the lower structure 3 is not limited to the relative position between the upper structure 1 and the lower structure 3 before vibration (before an earthquake or wind). The relative position between the upper structure 1 and the lower structure 3 at a certain point during vibration may be used as the reference position between the upper structure 1 and the lower structure 3.

[0027] In FIG. 2, the range where the relative displacement x is negative (minus) is defined as the range where the upper structure 1 is located to the left of the reference position when viewed from the lower structure 3. Also, the range where the relative displacement x is positive (plus) is defined as the range where the upper structure 1 is located to the right of the reference position when viewed from the lower structure 3.

[0028] In FIG. 2, the vertical axis represents the load F on the structure 100. Here, the restoring force is the force that tries to return the positional relationship between the upper structure 1 and the lower structure 3 to the reference position when the upper structure 1 and the lower structure 3 are relatively displaced from the reference position. Specifically, in the range where the upper structure 1 is located to the left of the reference position when viewed from the lower structure 3, since the average of the load during the movement away from the reference position and the load during the movement closer to the reference position is a negative value, a leftward force that tries to separate the upper structure 1 from the reference position side acts. Also, in the range where the upper structure 1 is located to the right of the reference position when viewed from the lower structure 3, since the average of the load during the movement away from the reference position and the load during the movement closer to the reference position is a positive value, a rightward force that tries to separate the upper structure 1 from the reference position side acts.

[0029] In FIG. 2, the direction of the load F that moves the upper structure 1 to the right as viewed from the lower structure 3 is defined as the negative (minus) direction. The direction of the load F that moves the upper structure 1 to the left as viewed from the lower structure 3 is defined as the positive (plus) direction.

[0030] In FIG. 2, the restoring force characteristics of the damping device of the comparative example are shown by a broken line. Here, the damping device of the comparative example has, for example, an ordinary oil damper such as the one described above with only a simple flow path provided in the cylinder. The restoring force characteristics of the damping device of the comparative example transition as M1’→M2’→M3’→M4’ as shown by the broken line in FIG. 2.

[0031] In the structure to which the damping device of the comparative example is applied, as shown by the broken line in FIG. 2, the magnitude of the load F when the upper structure 1 moves closer to the reference position as viewed from the lower structure 3 is the same as the magnitude of the load F when the upper structure 1 moves away from the reference position as viewed from the lower structure 3. That is, the magnitude of the load F at M1’ is the same as the magnitude of the load F at M4’, and the magnitude of the load F at M2’ is the same as the magnitude of the load F at M3’. In the structure to which the damping device of the comparative example is applied, since the average of the load during the movement away from the reference position and the load during the movement closer to the reference position is 0, the virtual restoring force is 0.

[0032] In FIG. 2, the restoring force characteristics of the damping device 10 of the present embodiment are shown by a solid line. As shown by the solid line in FIG. 2, the restoring force characteristics of the damping device 10 of the present embodiment transition as M1→M2→M3→M4. In the structure 100 to which the damping device 10 of the present embodiment is applied, the load F when the upper structure 1 approaches the reference position as viewed from the lower structure 3 and the load F when the upper structure 1 moves away from the reference position as viewed from the lower structure 3 have different characteristics. Specifically, the magnitude of the load F when the upper structure 1 approaches the reference position as viewed from the lower structure 3 is larger than the magnitude of the load F when the upper structure 1 moves away from the reference position as viewed from the lower structure 3. That is, the magnitude of the load F at M1 is larger than the magnitude of the load F at M4, and the magnitude of the load F at M3 is larger than the magnitude of the load F at M2.

[0033] Accordingly, in the structure 100 to which the damping device 10 of the present embodiment is applied, since the load increases when the upper structure 1 approaches the reference position as viewed from the lower structure 3, it virtually gives a negative stiffness, and thus, in the structure 100 of the seismic isolation structure having a certain restoring force, the response acceleration of the structure 100 can be further reduced.

[0034] The damping device 10 of the present embodiment operates in a high damping mode so that the magnitude of the load F becomes small when the upper structure 1 approaches the reference position as viewed from the lower structure 3 (M1 and M3 in FIG. 2). Further, the damping device 10 operates in a low damping mode so that the magnitude of the load F becomes large when the upper structure 1 moves away from the reference position as viewed from the lower structure 3 (M2 and M4 in FIG. 2).

[0035] Thus, the damping device 10 of the present embodiment operates by switching between the low damping mode and the high damping mode according to the relative displacement and the direction of relative movement between the upper structure 1 and the lower structure 3.

[0036] <<Configuration and Operation>> FIG. 3A is an explanatory diagram showing a state in which, in the damping device 10 of the present embodiment, when viewed from the piston 11, the cylinder 12 is located on the left side of the reference position and moves in the right direction. FIG. 3B is an explanatory diagram showing a state in which, in the damping device 10 of the present embodiment, when viewed from the piston 11, the cylinder 12 is located on the right side of the reference position and moves in the right direction. FIG. 4A is an explanatory diagram showing a state in which, in the damping device 10 of the present embodiment, when viewed from the piston 11, the cylinder 12 is located on the right side of the reference position and moves in the left direction. FIG. 4B is an explanatory diagram showing a state in which, in the damping device 10 of the present embodiment, when viewed from the piston 11, the cylinder 12 is located on the left side of the reference position and moves in the left direction.

[0037] Hereinafter, the configuration and operation of the damping device 10 that operates by switching between a low damping mode and a high damping mode according to the relative displacement and the direction of relative movement between the above-described upper structure 1 and the lower structure 3 will be described.

[0038] <Configuration> First, with reference to FIGS. 3A, 3B, 4A, and 4B, the detailed configuration of the damping device 10 of the present embodiment will be described.

[0039] The damping device 10 includes a piston 11, a cylinder 12, a first flow path 20, a second flow path 30, and a switching unit 60.

[0040] · Piston 11 The piston 11 is a member that slides within the cylinder 12 while being in close contact with the inner wall of the cylinder 12. As shown in FIGS. 3A, 3B, 4A, and 4B, the piston 11 is accommodated in the cylinder 12 and divides the space within the cylinder 12 into a first chamber 13 (described later) and a second chamber 14 (described later). The piston 11 is fixed to the lower structure 3 of the structure 100 via a rod 15.

[0041] · Cylinder 12 The cylinder 12 is a member that slidably houses the piston 11. The cylinder 12 is fixed to the upper structure 1 of the structure 100. The cylinder 12 has a first chamber 13 and a second chamber 14. The first chamber 13 is located on one side (left side) in the sliding direction of the piston 11, and the second chamber 14 is located on the other side (right side) in the sliding direction of the piston 11. Fluids (here, hydraulic oil) are enclosed in the first chamber 13 and the second chamber 14.

[0042] As described above, the piston 11 is fixed to the lower structure 3 of the structure 100, and the cylinder 12 is fixed to the upper structure 1 of the structure 100. Therefore, the relative movement between the upper structure 1 and the lower structure 3 corresponds to the relative movement between the cylinder 12 and the piston 11. Also, the relative displacement of the structure 100, that is, the relative displacement between the upper structure 1 and the lower structure 3, corresponds to the relative displacement between the cylinder 12 and the piston 11.

[0043] Therefore, in the following description, with reference to the predetermined positions of the piston 11 fixed to the lower structure 3 and the cylinder 12 fixed to the upper structure 1 as the reference positions, the relative movement between the piston 11 and the cylinder 12 will be described by the movement of the cylinder 12 as seen from the piston 11.

[0044] ·The first flow path 20 The first flow path 20 is a flow path that communicates the first chamber 13 and the second chamber 14 and through which fluids can pass. The first flow path 20 is provided in the cylinder 12 as shown in FIGS. 3A, 3B, 4A, and 4B. The first flow path 20 has a first rightward flow path 21 and a first leftward flow path 22. The first rightward flow path 21 is a flow path through which fluids pass in the rightward direction. Here, the rightward direction is the direction from the first chamber 13 side to the second chamber 14 side. The first leftward flow path 22 is a flow path through which fluids pass in the leftward direction. Here, the leftward direction is the direction from the second chamber 14 side to the first chamber 13 side.

[0045] The first flow path 20 has a predetermined flow path resistance (hereinafter, sometimes referred to as "the first flow path resistance"). The first flow path resistance is determined by the inner diameter of the first flow path 20 and the like.

[0046] The first flow path 20 has a first valve section 40. The first valve section 40 is a member for allowing the fluid in the first flow path 20 to pass only in either the right direction or the left direction. The first valve section 40 may be any one of a pressure regulating valve, a relief valve, a check valve, a suction valve, etc., or a combination of a plurality of valves in parallel. Further, when the difference between the pressure of the fluid in the first chamber 13 and the pressure of the fluid in the second chamber 14 becomes equal to or greater than a predetermined pressure difference (hereinafter sometimes referred to as the "first pressure difference"), the first valve section 40 enables the fluid to pass in the right direction or the left direction.

[0047] The first valve section 40 has a first right-direction valve 41 and a first left-direction valve 42.

[0048] The first right-direction valve 41 is a member that changes from a closed state to an open state and enables the fluid to pass in the right direction when the difference obtained by subtracting the pressure of the fluid in the second chamber 14 from the pressure of the fluid in the first chamber 13 is equal to or greater than the first pressure difference. The first right-direction valve 41 is provided in the first right-direction flow path 21.

[0049] The first left-direction valve 42 is a member that changes from a closed state to an open state and enables the fluid to pass in the left direction when the difference obtained by subtracting the pressure of the fluid in the first chamber 13 from the pressure of the fluid in the second chamber 14 is equal to or greater than the first pressure difference. The first left-direction valve 42 is provided in the first left-direction flow path 22.

[0050] FIG. 5A is an explanatory diagram showing the state of the first right-direction valve 41 in the closed state. FIG. 5B is an explanatory diagram showing the state of the first right-direction valve 41 in the open state.

[0051] Here, with reference to FIGS. 5A and 5B, the details of the closed state and the open state of the first right-direction valve 41 will be described.

[0052] The first right-direction valve 41 has a valve body 43 and an elastic member 44. The valve body 43 is a member that switches between opening and closing the first right-direction flow path 21. The elastic member 44 is a member for restoring the positional relationship of the valve body 43 within the first right-direction flow path 21. As shown in FIGS. 5A and 5B, the valve body 43 is located on the first chamber 13 side, and the elastic member 44 is located on the second chamber 14 side. That is, the valve body 43 is pressed by the elastic member 44 in a direction that adheres to the edge of the opening of the first right-direction flow path 21 on the first chamber 13 side.

[0053] As shown in FIG. 5A, when the pressure of the fluid in the second chamber 14 is higher than the pressure of the fluid in the first chamber 13, the fluid attempts to move leftward through the first right-direction flow path 21. However, the valve body 43 is pressed by the elastic member 44 and adheres to the edge of the opening of the first right-direction flow path 21 on the first chamber 13 side, causing the first right-direction valve 41 to be in a closed state. When the first right-direction valve 41 is in the closed state, the fluid cannot pass through the first right-direction flow path 21. That is, when the pressure of the fluid in the second chamber 14 is higher than the pressure of the fluid in the first chamber 13, the fluid cannot move to the left side.

[0054] As shown in FIG. 5B, when the pressure of the fluid in the first chamber 13 is higher than the pressure of the fluid in the second chamber 14, the fluid attempts to move rightward through the first right-direction flow path 21. Further, when the difference obtained by subtracting the pressure of the fluid in the second chamber 14 from the pressure of the fluid in the first chamber 13 is equal to or greater than the first pressure difference, the valve body 43 moves from the edge of the opening of the first right-direction flow path 21 on the first chamber 13 side to the second chamber 14 side against the pressing force of the elastic member 44 due to the first pressure. As a result, the first right-direction valve 41 changes from the closed state to the open state, enabling the fluid to pass through in the right direction.

[0055] In FIGS. 5A and 5B, the height of the fluid pressure is represented by the color density in the first chamber 13 and the second chamber 14. That is, FIG. 5A shows the case where the fluid pressure in the second chamber 14 is higher than the fluid pressure in the first chamber 13, and FIG. 5B shows the case where the fluid pressure in the first chamber 13 is higher than the fluid pressure in the second chamber 14. The method of expressing the height of the fluid pressure by the above-described color density is the same in FIGS. 3A, 3B, 4A, and 4B.

[0056] Note that the above description of the closed state and the open state of the first right-direction valve 41 is the same for the first left-direction valve 42. However, for the first left-direction valve 42, the left-right positional relationship between the valve body 43 and the elastic member 44 and the fluid movement direction are reversed left and right. That is, for the first left-direction valve 42, the valve body 43 is located on the second chamber 14 side, and the elastic member 44 is located on the first chamber 13 side. Also, when the fluid pressure in the first chamber 13 is higher than the fluid pressure in the second chamber 14, the fluid cannot move to the right direction side, and when the difference obtained by subtracting the fluid pressure in the second chamber 14 from the fluid pressure in the first chamber 13 is equal to or greater than the first pressure difference, the fluid can pass through to the left direction.

[0057] ·Second flow path 30 The second flow path 30 is a flow path different from the first flow path 20, communicates the first chamber 13 and the second chamber 14, and is a flow path through which the fluid can pass. The second flow path 30 is provided outside the cylinder 12 as shown in FIGS. 3A, 3B, 4A, and 4B. However, the second flow path 30 may be provided inside the cylinder 12. The second flow path 30 has a second right-direction flow path 31 and a second left-direction flow path 32. The second right-direction flow path 31 is a flow path through which the fluid passes in the right direction. The second left-direction flow path 32 is a flow path through which the fluid passes in the left direction.

[0058] The second flow path 30 has a predetermined flow path resistance (hereinafter, may be referred to as "second flow path resistance") smaller than the first flow path resistance. The second flow path resistance is determined by the inner diameter of the second flow path 30 and the like.

[0059] The second flow path 30 has a second valve section 50. The second valve section 50 is a member for allowing the fluid in the second flow path 30 to pass only in either the right direction or the left direction. The second valve section 50 may be any one of a pressure regulating valve, a relief valve, a check valve, a suction valve, etc., or a combination of a plurality of valves in parallel. Also, when the difference between the pressure of the fluid in the first chamber 13 and the pressure of the fluid in the second chamber 14 becomes equal to or greater than a predetermined pressure difference (hereinafter sometimes referred to as the "second pressure difference") that is smaller than the first pressure difference, the second valve section 50 enables the fluid to pass in the right direction or the left direction.

[0060] The second valve section 50 has a second right-direction valve 51 and a second left-direction valve 52.

[0061] The second right-direction valve 51 is a member that, when the difference obtained by subtracting the pressure of the fluid in the second chamber 14 from the pressure of the fluid in the first chamber 13 becomes equal to or greater than the second pressure difference, changes from the closed state to the open state and enables the fluid to pass in the right direction. The second right-direction valve 51 is provided in the second right-direction flow path 31.

[0062] The second left-direction valve 52 is a member that, when the difference obtained by subtracting the pressure of the fluid in the first chamber 13 from the pressure of the fluid in the second chamber 14 becomes equal to or greater than the second pressure difference, changes from the closed state to the open state and enables the fluid to pass in the left direction. The second left-direction valve 52 is provided in the second left-direction flow path 32.

[0063] Note that the descriptions of the closed state and open state of the second right-direction valve 51 and the second left-direction valve 52 are the same as the descriptions of the closed state and open state of the first right-direction valve 41 described above. However, for the second left-direction valve 52, the left-right positional relationship between the valve body 43 and the elastic member 44 and the fluid movement direction are reversed left and right. That is, for the second left-direction valve 52, the valve body 43 is located on the second chamber 14 side, and the elastic member 44 is located on the first chamber 13 side. Also, when the pressure of the fluid in the first chamber 13 is higher than the pressure of the fluid in the second chamber 14, the fluid cannot move to the right direction side, and when the difference obtained by subtracting the pressure of the fluid in the second chamber 14 from the pressure of the fluid in the first chamber 13 is equal to or greater than the second pressure difference, the fluid can pass through to the left direction.

[0064] · Switching unit 60 The switching unit 60 is a member that switches the passageability of fluid in at least one of the right direction and the left direction in the second flow path 30 based on the relative position between the piston 11 and the cylinder 12. In the damping device 10 of the present embodiment, the switching unit 60 is provided in the second flow path 30 and moves together with the cylinder 12. However, the switching unit 60 may be provided independently of other configurations (here, the second flow path 30) as long as it can detect the relative position between the piston 11 and the cylinder 12. The switching unit 60 includes a displacement detection unit 61, a second right-direction opening 62, a second left-direction opening 63, and an elastic member 64.

[0065] The displacement detection unit 61 is a part that detects the switching point of the relative displacement between the piston 11 and the cylinder 12. The displacement detection unit 61 is formed as a member extending in the vertical direction, and the lower end (lower end) of the displacement detection unit 61 is in contact with the first step portion 6 or the second step portion 7 of the lower structure 3. Here, the first step portion 6 is at a higher position in the height direction than the second step portion 7 (conversely, the second step portion 7 is at a lower position in the height direction than the first step portion 6). In other words, the lower structure 3 includes a multi-step portion having the first step portion 6 and the second step portion 7 with different displacements in the height direction.

[0066] Therefore, when the lower end of the displacement detection unit 61 is in contact with the first step portion 6 (as shown in FIGS. 3A and 4B), the displacement detection unit 61 is positioned at a higher position than when the lower end of the displacement detection unit 61 is in contact with the second step portion 7. Also, when the lower end of the displacement detection unit 61 is in contact with the second step portion 7 (as shown in FIGS. 3B and 4A), the displacement detection unit 61 is positioned at a lower position than when the lower end of the displacement detection unit 61 is in contact with the first step portion 6.

[0067] Accordingly, as shown in FIGS. 3A, 3B, 4A, and 4B, when the piston 11 and the cylinder 12 move relative to each other and the lower end of the displacement detection unit 61 passes through the variable portion 8 of the lower structure 3, the position of the displacement detection unit 61 in the height direction is switched.

[0068] The second rightward opening 62 is an opening formed in the displacement detection unit 61. The second rightward opening 62 switches between a position where the second rightward flow path 31 is opened and a position where the second rightward flow path 31 is blocked according to the position of the switching unit 60 in the height direction (specifically, the position of the displacement detection unit 61 in the height direction). Specifically, when the lower end of the displacement detection unit 61 is in contact with the first step portion 6 (as shown in FIGS. 3A and 4B), it is positioned at a position where the second rightward flow path 31 is blocked. Also, when the lower end of the displacement detection unit 61 is in contact with the second step portion 7 (as shown in FIGS. 3B and 4A), it is positioned at a position where the second rightward flow path 31 is opened.

[0069] The second leftward opening 63 is an opening formed in the displacement detection unit 61. The second leftward opening 63 switches between a position where the second leftward flow path 32 is opened and a position where the second leftward flow path 32 is blocked according to the position of the switching unit 60 in the height direction (specifically, the position of the displacement detection unit 61 in the height direction). Specifically, when the lower end of the displacement detection unit 61 is in contact with the first step portion 6 (as shown in FIGS. 3A and 4B), it is positioned at a position where the second leftward flow path 32 is opened. Also, when the lower end of the displacement detection unit 61 is in contact with the second step portion 7 (as shown in FIGS. 3B and 4A), it is positioned at a position where the second leftward flow path 32 is blocked.

[0070] The elastic member 64 is a member that restores the height-direction position of the displacement detection unit 61. As shown in FIG. 3A, the elastic member 64 is a coil spring. However, the elastic member 64 may be an elastic member other than a coil spring, such as a leaf spring or rubber, or the elastic member may be omitted altogether and allowed to fall by its own weight. In the present embodiment, when the lower end of the displacement detection unit 61 moves from the second step portion 7 to the first step portion 6, an upward force is applied, so that, as shown in FIGS. 3A and 4B, the elastic member 64 deforms upward. When the lower end of the displacement detection unit 61 moves from the first step portion 6 to the second step portion 7, as shown in FIGS. 3B and 4A, the deformed elastic member 64 is restored and deforms downward.

[0071] In addition to the above-described configuration, the switching unit 60 may further include a lever mechanism, an amplification mechanism, or the like in order to smoothly switch between opening and closing the second flow path 30.

[0072] <Operation> Next, the operation of the damping device 10 of the present embodiment will be described with reference to FIGS. 3A, 3B, 4A, and 4B described above.

[0073] FIG. 3A shows a case where the cylinder 12 is located on the left side of the reference position and moves in the right direction as viewed from the piston 11. In this case, since the pressure of the fluid in the first chamber 13 is higher than the pressure of the fluid in the second chamber 14, the fluid tries to move in the right direction through either the first right-direction flow path 21 (first right-direction valve 41) or the second right-direction flow path 31 (second right-direction valve 51).

[0074] Here, as shown in FIG. 3A, the switching unit 60 closes the second right-direction flow path 31, so that the fluid cannot pass through the second right-direction flow path 31. Therefore, when the difference obtained by subtracting the pressure of the fluid in the second chamber 14 from the pressure of the fluid in the first chamber 13 becomes equal to or greater than the first pressure difference, the fluid passes through the first right-direction valve 41. In the state of FIG. 3A, the damping device 10 operates in the high-damping mode (the fluid passes through the first flow path 20) and corresponds to M1 of the restoring force characteristics shown in FIG. 2 described above.

[0075] FIG. 3B shows the case where the cylinder 12 is located on the right side of the reference position and moves in the right direction as viewed from the piston 11. Also in this case, since the pressure of the fluid in the first chamber 13 becomes higher than the pressure of the fluid in the second chamber 14, the fluid tries to move rightward through either the first rightward flow path 21 (first rightward valve 41) or the second rightward flow path 31 (second rightward valve 51).

[0076] Here, as shown in FIG. 3B, the switching section 60 opens the second rightward flow path 31, so that the fluid can pass through the second rightward flow path 31. When the difference obtained by subtracting the pressure of the fluid in the second chamber 14 from the pressure of the fluid in the first chamber 13 becomes equal to or greater than the second pressure difference, the fluid passes through the second rightward valve 51. On the other hand, the fluid does not pass through the first rightward valve 41 which becomes passable when the first pressure difference which is greater than the second pressure difference becomes equal to or greater than the first pressure difference. In the state of FIG. 3B, the damping device 10 operates in the low damping mode (the fluid passes through the second flow path 30), corresponding to M2 of the restoring force characteristic shown in FIG. 2 described above.

[0077] FIG. 4A shows the case where the cylinder 12 is located on the right side of the reference position and moves in the left direction as viewed from the piston 11. In this case, since the pressure of the fluid in the second chamber 14 becomes higher than the pressure of the fluid in the first chamber 13, the fluid tries to move leftward through either the first leftward flow path 22 (first leftward valve 42) or the second leftward flow path 32 (second leftward valve 52).

[0078] Here, as shown in FIG. 4A, the switching section 60 closes the second leftward flow path 32, so that the fluid cannot pass through the second leftward flow path 32. Therefore, when the difference obtained by subtracting the pressure of the fluid in the first chamber 13 from the pressure of the fluid in the second chamber 14 becomes equal to or greater than the first pressure difference, the fluid passes through the first leftward valve 42. In the state of FIG. 4A, the damping device 10 operates in the high damping mode (the fluid passes through the first flow path 20), corresponding to M3 of the restoring force characteristic shown in FIG. 2 described above.

[0079] FIG. 4B shows a case where the cylinder 12 is located to the left of the reference position and moves leftward when viewed from the piston 11. Also in this case, since the pressure of the fluid in the second chamber 14 becomes higher than the pressure of the fluid in the first chamber 13, the fluid tries to move leftward through either the first leftward flow path 22 (first leftward valve 42) or the second leftward flow path 32 (second leftward valve 52).

[0080] Here, as shown in FIG. 4B, the switching unit 60 opens the second leftward flow path 32, so that the fluid can pass through the second leftward flow path 32. When the difference obtained by subtracting the pressure of the fluid in the first chamber 13 from the pressure of the fluid in the second chamber 14 is equal to or greater than the second pressure difference, the fluid passes through the second leftward valve 52. On the other hand, the fluid does not pass through the first leftward valve 42 which becomes passable when the first pressure difference is greater than the second pressure difference. In the state of FIG. 4B, the damping device 10 operates in the low damping mode (the fluid passes through the second flow path 30), corresponding to M4 of the restoring force characteristics shown in FIG. 2 described above (when the relative displacement x of the structure 100 is negative and moves relatively in the negative direction).

[0081] As described above, the damping device 10 switches between the low damping mode and the high damping mode according to the relative displacement and the direction of relative movement between the upper structure 1 (cylinder 12) and the lower structure 3 (piston 11). That is, the damping device 10 enters the high damping mode when the switching unit 60 closes the second flow path 30 only when the upper structure 1 (cylinder 12) moves closer to the reference position when viewed from the lower structure 3 (piston 11), and a restoring force characteristic close to negative stiffness can be obtained. Thereby, in the damping device 10 of the present embodiment, in the structure 100 of the seismic isolation structure having a constant restoring force, the response acceleration of the structure 100 can be further reduced. And it can suppress the resonance with the seismic motion and contribute to the reduction of the acceleration of the upper structure 1 (such as a building).

[0082] <<Modification Example>> <First Modification Example> FIG. 6A is an explanatory diagram showing a state in which, in the damping device 10A of the first modification, as viewed from the piston 11, the cylinder 12 is located on the left side of the reference position and moves in the right direction. FIG. 6B is an explanatory diagram showing a state in which, in the damping device 10A of the first modification, as viewed from the piston 11, the cylinder 12 is located on the right side of the reference position and moves in the left direction.

[0083] In the damping device 10 of the above-described embodiment, the first-stage portion 6, the second-stage portion 7, and the variable portion 8 detected by the displacement detection portion 61 of the switching portion 60 were formed in the lower structure 3 (in other words, fixed to the lower structure 3). However, the first-stage portion 6, the second-stage portion 7, and the variable portion 8 do not have to be fixed to the lower structure 3 as long as they are portions that displace in the same manner as the piston 11.

[0084] In the damping device 10A of the first modification, as shown in FIGS. 6A and 6B, the first-stage portion 6A, the second-stage portion 7A, and the variable portion 8A may be formed on the variable portion member 4A fixed to the piston 11 (specifically, the rod 15). In the damping device 10A of the first modification, in the structure 100 of the seismic isolation structure having a certain restoring force, the response acceleration of the structure 100 can be further reduced.

[0085] <Second Modification> FIG. 7A is an explanatory diagram showing a state in which, in the damping device 10B of the second modification, as viewed from the piston 11, the cylinder 12 is located on the left side of the reference position and moves in the right direction. FIG. 7B is an explanatory diagram showing a state in which, in the damping device 10B of the second modification, as viewed from the piston 11, the cylinder 12 is located on the right side of the reference position and moves in the left direction.

[0086] In the damping device 10 of the above-described embodiment, the variable portion 8, which is the switching point of the relative displacement between the piston 11 and the cylinder 12, was formed as a step between the first-stage portion 6 and the second-stage portion 7. However, the variable portion 8 does not have to be formed as a step between the first-stage portion 6 and the second-stage portion 7.

[0087] In the damping device 10B of the second modification, as shown in FIGS. 7A and 7B, the variable portion 8B is formed as a groove on the lower structure 3. Further, in the damping device 10B, the switching portion 60B is formed as an L-shaped switch member. Specifically, in the switching portion 60B, a displacement detection portion 61B that detects the variable portion 8B and a pressing portion 65 that presses the switching portion 60B main body (the portion where the second rightward opening 62 and the second leftward opening 63 are formed) are connected to a rotation shaft 66.

[0088] In the switching portion 60B, as shown in FIGS. 7A and 7B, the opening and closing of the second flow path 30 are switched by a mechanical mechanism, but the displacement may be detected and the opening and closing of the second flow path 30 may be switched electromagnetically. In the damping device 10B of the second modification, in the structure 100 of the seismic isolation structure having a certain restoring force, the response acceleration of the structure 100 can be further reduced.

[0089] <Third Modification> FIG. 8A is an explanatory diagram showing a state in which the cylinder 12 is located on the left side of the reference position and moves rightward as viewed from the piston 11 in the damping device 10C of the third modification. FIG. 8B is an explanatory diagram showing a state in which the cylinder 12 is located on the right side of the reference position and moves leftward as viewed from the piston 11 in the damping device 10C of the third modification.

[0090] The switching point of the displacement of the cylinder 12 with respect to the piston 11 may be an absolute displacement instead of a relative displacement like the damping device 10 of the present embodiment. In the damping device 10C of the third modification, a reference position as an absolute displacement is provided, and a variable portion member 4C that is formed separately from the relative movement between the upper structure 1 (cylinder 12) and the lower structure 3 (piston 11) may be provided. By performing switching based on the reference position of the variable portion member 4C, it is possible to realize a behavior that reduces the response in the absolute space.

[0091] The member 4C for the variable part is formed with a passive structure using a roller or the like, but may further have a spring member (not shown) that adds a restoring force. Further, the member 4C for the variable part may be formed with an active structure using an actuator or the like. Note that the member 4C for the variable part has a reference position as an absolute displacement, but is not limited thereto, and a position that simulates the displacement to be realized may be used as the reference position. For example, in the case of seismic motion that causes permanent deformation, the target displacement may be gradually brought closer to the permanent displacement.

[0092] Note that in the case of the configuration as shown in FIGS. 8A and 8B, for example, when the displacement detection unit 61 of the switching unit 60 passes the variable part 8C from the second-stage part 7C side to the first-stage part 6C side, a leftward force acts on the member 4C for the variable part. Even in this case, by adopting a configuration in which the directions of the steps are opposite to each other, such as the damping device 10F of the sixth modification example and the damping device 10G of the seventh modification example described later, it is possible to reduce the force acting on the member 4C for the variable part.

[0093] In the damping device 10C of the third modification example, in the structure 100 of the seismic isolation structure having a constant restoring force, the response acceleration of the structure 100 can be further reduced.

[0094] <Fourth Modification Example> FIG. 9A is an explanatory view showing a state in which the cylinder 12 is located at the reference position and moves to the right as viewed from the piston 11 in the damping device 10D of the fourth modification example. FIG. 9B is an explanatory view showing a state in which the cylinder 12 is located at the reference position and moves to the left as viewed from the piston 11 in the damping device 10D of the fourth modification example.

[0095] Similar to the damping device 10D of the fourth modification example, as shown in FIGS. 9A and 9B, by having a plurality of steps (fluctuating portion 8), the switching point of the relative displacement between the piston 11 and the cylinder 12 may be made multi-stage. Specifically, the multi-stage portion further has a third-stage portion 9 whose displacement in the height direction is the displacement between the first-stage portion 6 and the second-stage portion 7. When the displacement detection unit 61 detects the displacement in the height direction of the third-stage portion 9, the relative position between the piston 11 and the cylinder 12 is at the reference position. The switching unit 60 closes the second right-direction flow path 31 and the second left-direction flow path 32 when the relative position between the piston 11 and the cylinder 12 is at the reference position. Thereby, at the reference position, the damping device 10D operates in the high-damping mode.

[0096] FIG. 10 is an explanatory diagram showing an example of the restoring force characteristics of the structure 100 by the damping device 10D of the fourth modification example.

[0097] In the damping device 10D of the fourth modification example, in the structure 100 of the seismic isolation structure having a constant restoring force, the response acceleration of the structure 100 can be further reduced. Further, as shown in FIG. 10, since the restoring force characteristics by the damping device 10D of the fourth modification example are highly damped in the vicinity of the reference position (reference position region in FIG. 10), the response to small and medium earthquakes and wind can be improved.

[0098] <Fifth Modification Example> FIG. 11A is an explanatory diagram showing a state in which the cylinder 12 is located on the left side of the reference position and moves to the right as viewed from the piston 11 in the damping device 10E of the fifth modification example. FIG. 11B is an explanatory diagram showing a state in which the cylinder 12 is located on the right side of the reference position and moves to the left as viewed from the piston 11 in the damping device 10E of the fifth modification example.

[0099] In the above-described damping device, it was of the double-rod type in which rods 15 were provided on both the left and right sides of the piston 11. However, it may be of the single-rod type like the damping device 10E of the fifth modification. As shown in FIGS. 11A and 11B, the damping device 10E further has a tank 16 for storing oil. In the damping device 10E of the fifth modification, in a structure 100 of a seismic isolation structure having a certain restoring force, the response acceleration of the structure 100 can be further reduced.

[0100] <Sixth Modification> FIG. 12A is an explanatory view showing a state in which the cylinder 12 is located on the right side of the reference position as viewed from the piston 11 in the damping device 10F of the sixth modification. FIG. 12B is an explanatory view showing the state of the damping device 10F in the S1-S1 cross section of FIG. 12A.

[0101] In the damping device 10F of the sixth modification, the switching portion 60F on the second rightward flow path 31 side and the switching portion 60F on the second leftward flow path 32 side are separately provided in the horizontal direction. In the damping device 10F of the sixth modification, even when the restoring force by the seismic isolation device 5 is reduced, by adjusting the damping force by the damping device 10F, it is possible to suppress the occurrence of residual deformation in the structure 100.

[0102] <Seventh Modification> FIG. 13A is an explanatory view showing the state of the switching portion 60G for each relative position of the piston 11 and the cylinder 12 in the damping device 10G of the seventh modification. FIG. 13B is an explanatory view showing the state of the damping device 10G in the S2-S2 cross section of FIG. 13A. FIG. 13C is an explanatory view showing the state of the damping device 10G in the S3-S3 cross section of FIG. 13A.

[0103] In the damping device 10G of the seventh modification, similar to the damping device 10F of the sixth modification, the switching portion 60G on the second rightward flow path 31 side and the switching portion 60G on the second leftward flow path 32 side are separately provided in the horizontal direction. Further, as shown in FIG. 13A, a configuration is adopted in which the directions of the first step portion 6, the second step portion 7, and the variable portion 8 are opposite to each other. Thereby, the force applied to the variable portion 8 due to the passage of the switching portion 60G can be canceled out.

[0104] In the damping device 10G of the seventh modification, in the structure 100 with a seismic isolation structure having a constant restoring force, the response acceleration of the structure 100 can be further reduced.

[0105] <Eighth Modification> FIG. 14A is an explanatory view showing the state of the switching portion 60H for each relative position of the piston 11 and the cylinder 12 in the damping device 10H of the eighth modification. FIG. 14B is an explanatory view showing the state of the damping device 10H of the S4-S4 cross section of FIG. 14A. FIG. 14C is an explanatory view showing the state of the damping device 10H of the S5-S5 cross section of FIG. 14A. FIG. 14D is an explanatory view showing the state of the damping device 10H of the S6-S6 cross section of FIG. 14A.

[0106] In the damping device 10H of the eighth modification, similarly to the damping device 10G of the seventh modification, the switching portion 60H on the second right direction flow path 31 side and the switching portion 60H on the second left direction flow path 32 side are separately provided in the horizontal direction. Further, as shown in FIG. 14A, a configuration in which the directions of the first step portion 6, the second step portion 7, and the variable portion 8 are opposite to each other is adopted, and further, the first step portion 6 is formed so as to overlap.

[0107] In the damping device 10H of the eighth modification, in the structure 100 with a seismic isolation structure having a constant restoring force, the response acceleration of the structure 100 can be further reduced. Further, similarly to the damping device 10D of the fourth modification, since the restoring force characteristic by the damping device 10H is highly damped at the reference position, the response to small and medium earthquakes and wind can be improved.

[0108] ==Summary== According to this specification, a damping device of the following aspect is provided.

[0109] (Aspect 1) Aspect 1 is a damping device 10 including a piston 11, a cylinder 12 that slidably houses the piston 11 and has a first chamber 13 located on one side in the sliding direction of the piston 11 and a second chamber 14 located on the other side in the sliding direction, and the first chamber 13 and the second chamber 14 in which a fluid is enclosed. Further, the damping device 10 includes a first flow path 20 that communicates the first chamber 13 and the second chamber 14 and has a first flow path resistance, and a second flow path 30 that is a flow path different from the first flow path 20, communicates the first chamber 13 and the second chamber 14, and has a second flow path resistance smaller than the first flow path resistance. Further, the damping device 10 includes a switching unit 60 that switches the passageability of the fluid in the second flow path 30 in one or both of the right direction, which is the direction from the first chamber 13 side to the second chamber 14 side, and the left direction, which is the direction from the second chamber 14 side to the first chamber 13 side, based on the relative position between the piston 11 and the cylinder 12.

[0110] In the damping device 10, with a predetermined position of the cylinder 12 as viewed from the piston 11 as a reference position, when the cylinder 12 moves in the right direction as viewed from the piston 11 and the position of the cylinder 12 as viewed from the piston 11 is located on the left side of the reference position, the fluid passes through the first flow path 20, and when the position of the cylinder 12 as viewed from the piston 11 is located on the right side of the reference position, the fluid passes through the second flow path 30. Further, in the damping device 10, when the cylinder 12 moves in the left direction as viewed from the piston 11 and the position of the cylinder 12 as viewed from the piston 11 is located on the right side of the reference position, the fluid passes through the first flow path 20, and when the position of the cylinder 12 as viewed from the piston 11 is located on the left side of the reference position, the fluid passes through the second flow path 30.

[0111] According to the above aspect, in a structure 100 of a seismic isolation structure having a certain restoring force, the response acceleration of the structure 100 can be further reduced.

[0112] (Aspect 2) In Mode 2, the second flow path 30 has a second rightward flow path 31 through which fluid passes rightward and a second leftward flow path 32 through which fluid passes leftward. When the position of the cylinder 12 as seen from the piston 11 is to the left of the reference position, the switching unit 60 closes the second rightward flow path 31 and opens the second leftward flow path 32. When the position of the cylinder 12 as seen from the piston 11 is to the right of the reference position, the switching unit 60 closes the second leftward flow path 32 and opens the second rightward flow path 31.

[0113] According to the above aspect, in the structure 100 of the seismic isolation structure having a certain restoring force, the response acceleration of the structure 100 can be further reduced.

[0114] (Mode 3) In Mode 3, when the relative position of the piston 11 and the cylinder 12 is at the reference position, the switching unit 60 closes the second rightward flow path 31 and the second leftward flow path 32.

[0115] According to the above aspect, the restoring force characteristic can be made highly damped near the reference position, and the response to small and medium earthquakes and wind can be improved.

[0116] (Mode 4) In Mode 4, the first flow path 20 has a first valve portion 40 that enables fluid to pass rightward or leftward when the difference between the pressure of the fluid in the first chamber 13 and the pressure of the fluid in the second chamber 14 is equal to or greater than a first pressure difference, and a second valve portion 50 that enables fluid to pass rightward or leftward when the difference between the pressure of the fluid in the first chamber 13 and the pressure of the fluid in the second chamber 14 is less than the first pressure difference and equal to or greater than a second pressure difference.

[0117] According to the above aspect, in the structure 100 of the seismic isolation structure having a certain restoring force, the response acceleration of the structure 100 can be further reduced.

[0118] (Mode 5) In aspect 5, a stepped portion having a first stepped portion 6 and a second stepped portion 7 with different displacements in the height direction according to the relative position between the piston 11 and the cylinder 12 is provided. The switching portion 60 has a displacement detection portion 61 that detects the displacement in the height direction of the stepped portion. When the displacement detection portion 61 detects the displacement in the height direction of the first stepped portion 6, the position of the cylinder 12 as viewed from the piston 11 is located on the left side of the reference position. When the displacement detection portion 61 detects the displacement in the height direction of the second stepped portion 7, the position of the cylinder 12 as viewed from the piston 11 is located on the right side of the reference position.

[0119] According to the above aspect, in the structure 100 of the seismic isolation structure having a certain restoring force, the response acceleration of the structure 100 can be further reduced.

[0120] (Aspect 6) In aspect 6, the stepped portion further has a third stepped portion 9 whose displacement in the height direction is the displacement between the first stepped portion 6 and the second stepped portion 7. When the displacement detection portion 61 detects the displacement in the height direction of the third stepped portion 9, the relative position between the piston 11 and the cylinder 12 is at the reference position.

[0121] According to the above aspect, in the structure 100 of the seismic isolation structure having a certain restoring force, the response acceleration of the structure 100 can be further reduced.

[0122] (Aspect 7) In aspect 7, the stepped portion is integrally formed with the piston 11 or the cylinder 12.

[0123] According to the above aspect, in the structure 100 of the seismic isolation structure having a certain restoring force, the response acceleration of the structure 100 can be further reduced.

[0124] (Aspect 8) In aspect 8, the stepped portion is formed separately from the relative movement between the piston 11 and the cylinder 12.

[0125] According to the above aspect, in the structure 100 of the seismic isolation structure having a certain restoring force, the response acceleration of the structure 100 can be further reduced.

[0126] ==Others== The above embodiments are for facilitating the understanding of the present invention and are not for limiting and interpreting the present invention. Further, the present invention can be changed and improved without departing from its gist, and it goes without saying that the equivalents of the present invention are included therein.

Description of Reference Numerals

[0127] 1 Superstructure 3 Substructure 4A, 4C Members for variable part 5 Seismic isolation device 6, 6A, 6C First-stage part 7, 7A, 7C Second-stage part 8, 8A, 8C Variable part 9 Third-stage part 10, 10~10G Damping device 11 Piston 12 Cylinder 13 First chamber 14 Second chamber 15 Rod 16 Tank 20 First flow path 21 First right-direction flow path 22 First left-direction flow path 30 Second flow path 31 Second right-direction flow path 32 Second left-direction flow path 40 First valve part 41 First right-direction valve 42 First left-direction valve 43 Valve body 44 Elastic member 50 Second valve part 51 Second right-direction valve 52 Second left-direction valve 60, 60B, 60F, 60G, 60H Switching part 61, 61B, 61F, 61G, 61H Displacement detection part 62, 62F, 62G, 62H Second right-direction opening 63, 63F, 63G, 63H Second left-direction opening 64, 64F, 64G, 64H Elastic member 65 Pressing part 66 Rotation axis 100 Structure

Claims

1. A piston, a cylinder that slidably houses the piston and has a first chamber located on one side in the sliding direction of the piston and a second chamber located on the other side in the sliding direction, the first chamber and the second chamber being filled with a fluid, a first flow path that communicates the first chamber and the second chamber and has a first flow path resistance, a second flow path that is a flow path different from the first flow path, communicates the first chamber and the second chamber, and has a second flow path resistance smaller than the first flow path resistance, a switching unit that switches the passage of the fluid in the second flow path in one or both of a right direction from the first chamber side to the second chamber side and a left direction from the second chamber side to the first chamber side based on the relative position between the piston and the cylinder, a damping device comprising: with a predetermined position of the cylinder as viewed from the piston as a reference position, when the cylinder moves in the right direction as viewed from the piston, when the position of the cylinder as viewed from the piston is to the left of the reference position, the fluid passes through the first flow path, when the position of the cylinder as viewed from the piston is to the right of the reference position, the fluid passes through the second flow path, when the cylinder moves in the left direction as viewed from the piston, when the position of the cylinder as viewed from the piston is to the right of the reference position, the fluid passes through the first flow path, when the position of the cylinder as viewed from the piston is to the left of the reference position, the fluid passes through the second flow path, a damping device.

2. The second flow path has a second right direction flow path through which the fluid passes in the right direction and a second left direction flow path through which the fluid passes in the left direction, The switching unit: when the position of the cylinder as viewed from the piston is to the left of the reference position, closes the second right direction flow path and opens the second left direction flow path, when the position of the cylinder as viewed from the piston is to the right of the reference position, closes the second left direction flow path and opens the second right direction flow path, The damping device according to Claim 1.

3. The switching unit: when the relative position between the piston and the cylinder is at the reference position, closes the second right direction flow path and the second left direction flow path, The damping device according to Claim 2.

4. When the difference between the pressure of the fluid in the first chamber and the pressure of the fluid in the second chamber is equal to or greater than a first pressure difference, the first flow path has a first valve portion that allows the fluid to pass in the right direction or the left direction. When the difference between the pressure of the fluid in the first chamber and the pressure of the fluid in the second chamber is equal to or greater than a second pressure difference that is smaller than the first pressure difference, the second flow path has a second valve portion that allows the fluid to pass in the right direction or the left direction. The damping device according to claim 1.

5. It includes a multi-step portion having a first step portion and a second step portion with different displacements in the height direction according to the relative position between the piston and the cylinder. The switching portion is provided with a displacement detection portion that detects the displacement in the height direction of the multi-step portion. When the displacement detection portion detects the displacement in the height direction of the first step portion, the position of the cylinder as seen from the piston is located to the left of the reference position. When the displacement detection portion detects the displacement in the height direction of the second step portion, the position of the cylinder as seen from the piston is located to the right of the reference position. The damping device according to claim 1.

6. The multi-step portion further has a third step portion whose displacement in the height direction is a displacement between the first step portion and the second step portion. When the displacement detection portion detects the displacement in the height direction of the third step portion, the switching portion has the relative position between the piston and the cylinder at the reference position. The damping device according to claim 5.

7. The multi-step portion is integrally formed with the piston or the cylinder. The damping device according to claim 5 or 6.

8. The multi-step portion is formed separately from the relative movement between the piston and the cylinder. The damping device according to claim 5 or 6.

Images