JP2018204763A - Seismic isolator - Google Patents

Abstract

To provide a seismic isolator capable of reducing the characteristic frequency of the whole device while supporting the weight of the supported object.SOLUTION: A seismic isolator comprises: a cylinder 12 having a cylindrical shape with one closed end and installed on either the ground side or the supported object side; a piston 22 configured to be relatively displaceable in the cylinder axis direction in the cylinder 12 and installed on the other side of the ground side and the supported side; and a fluid flow channel 40 provided between the cylinder 12 and the piston 22 in a radial direction for communicating the inside of the cylinder 12 with the outside of the cylinder 12, and working fluid composed of viscous fluid is introduced into the cylinder 12 at a predetermined pressure while discharging it to the outside of the cylinder 12 through the fluid flow channel 40.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a seismic isolation device that mitigates shaking caused by an earthquake or the like.

In recent years, the number of buildings with a long natural period has increased due to the increase in the number of buildings, etc. As a seismic isolation structure that can withstand long-period vibration, the spring constant is smaller than that of metal springs, rubber springs, etc. Air spring is adopted.
For example, Patent Document 1 proposes a configuration in which a plurality of air springs are arranged close to each other and membrane-like cylindrical members constituting each air spring are connected by a connecting member. Each of these air springs is composed of a film-shaped cylindrical member having a constant volume, and the limited volume in the film-shaped cylindrical member is filled with air at a predetermined pressure.
And by setting it as such a structure, when the shaking by an earthquake is input, while an air spring absorbs a shaking, it suppresses that an air spring deform | transforms so that it may incline with respect to a horizontal surface.

JP 2011-144893 A

By the way, even if it is an air spring like patent document 1, you have to support the weight of the building which is a to-be-supported object. For this reason, a spring constant will become larger than the case where only absorption of a vibration is considered.
In addition, since the pressure inside the air spring changes depending on the magnitude of the swing and a large amplitude swing is input, the inside of the air spring becomes high pressure, so the spring constant is further increased. turn into.
As described above, in order to reduce the spring constant, there is a problem that even if an air spring having a constant volume is employed, the spring constant cannot be reduced as much as intended.

  The present invention has been made in view of the above, and an object of the present invention is to provide a seismic isolation device that can reduce the natural frequency of the supported object and the seismic isolation device while supporting the weight of the supported object. And

  To achieve the above object, a seismic isolation device according to the present invention has a cylindrical shape with one end closed, a cylinder installed on either the ground side or the supported object side, The inside of the cylinder is configured to be relatively displaceable along the cylinder axis direction, between the piston installed on the other of the ground side and the supported object side, and between the cylinder and the piston in the radial direction. And a fluid flow path communicating with the outside of the cylinder, and a working fluid made of a viscous fluid and supplied to the inside of the cylinder at a predetermined pressure and flowing out of the cylinder through the fluid flow path It is characterized by that.

  ADVANTAGE OF THE INVENTION According to this invention, the seismic isolation apparatus which can reduce the natural frequency which a to-be-supported object and a seismic isolation apparatus comprise can be provided, supporting the weight of a to-be-supported object.

It is a perspective view which shows the seismic isolation apparatus of 1st Embodiment. The standby state (equilibrium state) in the seismic isolation apparatus of 1st Embodiment is shown, (a) is sectional drawing along a cylinder axial direction, (b) is sectional drawing along the II-II line of (a). . Sectional drawing along the cylinder axis direction of the seismic isolation device of 1st Embodiment is shown, (a) is the case where the pressure of a working fluid is low with respect to a load, (b) is the pressure of a working fluid is high with respect to a load Is the case. The seismic isolation apparatus of another aspect of 1st Embodiment is shown, (a) is sectional drawing along a cylinder axial direction, (b) is sectional drawing along the IV-IV line of (a). It is sectional drawing which showed the standby state (equilibrium state) in the seismic isolation apparatus of 2nd Embodiment, and followed the cylinder-axis direction. Sectional drawing along the cylinder axis direction of the seismic isolation device of 2nd Embodiment is shown, (a) is the state which closed the fluid flow path, (b) is the state which opened the fluid flow path, (c) is fluid flow It is another form of the state which opened the path. It is sectional drawing which showed the stand-by state (equilibrium state) in the seismic isolation apparatus of 3rd Embodiment, and followed the cylinder-axis direction. It is sectional drawing which showed the standby state (equilibrium state) in the seismic isolation apparatus of another aspect of 3rd Embodiment, and followed the cylinder-axis direction. The seismic isolation apparatus of 4th Embodiment is shown, (a) is sectional drawing along the cylinder-axis direction in a standby state (equilibrium state), (b) is a perspective view which shows the guide body which comprises a seismic isolation apparatus. The seismic isolation apparatus of 1st another aspect of 4th Embodiment is shown, (a) is sectional drawing along a cylinder axial direction, (b) is sectional drawing along the XX line of (a). The seismic isolation apparatus of the 2nd another aspect of 4th Embodiment is shown, (a) is sectional drawing along a cylinder axial direction, (b) is sectional drawing along the XI-XI line of (a).

<First Embodiment>
Embodiments of the present invention will be described in detail with reference to the drawings. In the description, the same elements are denoted by the same reference numerals, and redundant description is omitted.
<Configuration of seismic isolation device>
The seismic isolation device 1 of the present embodiment is configured to block a unidirectional swing along an up-down direction due to an earthquake or the like, and as shown in FIG. 1, a cylinder-side member 10, a piston-side member 20, and a guide A mechanism 30 is provided. Further, when the seismic isolation device 1 is operated, air as a working fluid is supplied to the seismic isolation device 1 from a compressor (not shown). And the seismic isolation device 1 is installed between the foundation part (not shown) of the building and the building body (not shown). There are several installed at the location.
For convenience of explanation, the load W by the building body is shown in the form of a weight in the drawing.
Further, horizontal shaking is blocked by a separately provided horizontal seismic isolation device (not shown).
Air as a working fluid is a viscous fluid having compressibility.

As shown in FIG. 2, the cylinder side member 10 includes a cylinder base 11, a cylinder 12, and a flange 13.
The cylinder base 11 is a part installed on the foundation portion of the building on the ground side.
The cylinder 12 has a cylindrical shape, and one end on the ground side is closed by the cylinder base 11. The cylinder 12 is disposed with the other end opened upward so that the cylinder axis C12 extends in the vertical direction, and a piston 22 described later is inserted into the cylinder from above. A supply pipe 14 is connected to the cylinder 12.
The supply pipe 14 is a path for supplying the air pressurized by the compressor to the inside of the cylinder 12. An orifice 15 having an inner diameter set to a predetermined dimension is installed at the cylinder side end of the supply pipe 14.
The flange 13 is a part that supports the guide mechanism 30.

The piston side member 20 includes a piston base 21 and a piston 22.
The piston base 21 is a part installed in the building body on the supported object side.
The piston 22 is a member that is inserted into the cylinder 12 so as to be displaceable along the cylinder axis direction in the cylinder 12, and has a round bar shape. Further, the piston 22 is set so that the piston outer diameter D22 which is the outer diameter thereof is slightly smaller than the cylinder inner diameter D12 which is the inner diameter of the cylinder 12.

The dimensional difference between the cylinder inner diameter D12 and the piston outer diameter D22, that is, the distance between the cylinder 12 and the piston 22, exhibits a viscous resistance that prevents relative displacement between the cylinder inner peripheral surface and the piston outer peripheral surface. It is set to be a size that can be.
A space formed between the cylinder inner peripheral surface and the piston outer peripheral surface is set in the fluid flow path 40. That is, the fluid flow path 40 is formed between the cylinder 12 and the piston 22 in the radial direction, and communicates the inside of the cylinder 12 and the outside of the cylinder 12.

The guide mechanism 30 is configured to freely allow relative displacement in the axial direction while restricting relative displacement in the radial direction between the piston 22 and the cylinder 12, and the guide shaft 31 and the guide bearing 32. It has.
The guide shaft 31 has a round bar shape and is supported by the piston base 21 so as to be parallel to the cylinder axis C12 of the cylinder 12.
The guide bearing 32 supports the guide shaft 31 in a state in which the displacement in the radial direction is restricted while allowing the displacement of the guide shaft 31 in the axial direction freely.
In the present embodiment, four guide mechanisms 30 are arranged at equiangular intervals with respect to the circumferential direction of the cylinder 12 (see FIG. 1).

Next, the function of the seismic isolation device 1 of this embodiment will be described.
The piston-side member 20 is guided by the guide mechanism 30, so that the piston 22 is restricted in the radial direction in the cylinder 12 and the vertical direction (cylinder axis direction) in the cylinder 12. Displacement is possible freely. That is, the piston base 21 and the cylinder base 11 are configured to be relatively displaceable with respect to the cylinder axis direction.

[Standby]
While the seismic isolation device 1 of the present embodiment is operating, air pressurized by a compressor (not shown) is always supplied into the cylinder 12 through the supply pipe 14. The air supplied into the cylinder 12 flows out from the fluid flow path 40 while pushing up the piston 22.
The pressure and supply amount of the supplied air are set so that the force for pushing up the piston 22 and the load W applied to the piston 22 are balanced.
The force that pushes up the piston 22 is determined by the product of the pressure of the supplied air and the cross-sectional area of the piston 22. Further, the load W applied to the piston 22 is obtained by the sum of the weight of the building body supported by the seismic isolation device 1 and the weight of the piston-side member 20.

  For example, when the weight of the building body is too large compared to the pressure of the supplied air, the piston 22 cannot be pushed up as shown in FIG. Further, when the weight of the building body is too small compared to the pressure of the supplied air, the piston 22 is pushed up as shown in FIG. Therefore, as shown in FIG. 2, the pressure of the supplied air and the supply amount are adjusted so that the piston 22 is held (balanced) at the intermediate position.

When the piston 22 falls below the equilibrium position and the overlap between the piston 22 and the cylinder 12 increases, the viscous resistance increases, air becomes difficult to escape, the cylinder internal pressure increases, and the force that pushes the piston 22 toward the balance position is increased. work.
When the piston 22 rises above the equilibrium position and the overlap between the piston 22 and the cylinder 12 becomes small, the viscous resistance decreases, the air is easily released, the cylinder internal pressure decreases, and the load W applied to the piston 22 causes the piston 22 to move. Go down to the balanced position.
By such an action, the supply amount of the supplied air and the flow rate of the air flowing out from the fluid flow path 40 are balanced and held at the equilibrium position.
The standby state is a state in which no shaking is input and the state of being held at the equilibrium position is maintained and continued.

The air supply amount can be made constant by creating a choke flow through the orifice 15 of the supply pipe 14.
Further, the outflow amount from the fluid flow path 40 is determined by the relationship between the viscous resistance acting in the fluid flow path 40 and the pressure in the cylinder 12.

[Shock absorption state]
Next, a case where vertical vibration (swing) due to an earthquake or the like is input to the seismic isolation device 1 will be described.
When the position of the cylinder side member 10 rises due to the shaking of the earthquake, the pressure of the supplied air remains as it is and the weight of the building main body becomes the same as that temporarily increased. For this reason, the piston 22 and the cylinder 12 are displaced toward the relatively close position toward the equilibrium position with the increased weight, and the amount of air flowing out through the fluid flow path 40 increases.
However, when the piston 22 and the cylinder 12 approach each other, the overlap between the piston 22 and the cylinder 12 becomes larger than the standby state (equilibrium position).
When the overlap between the piston 22 and the cylinder 12 increases, the flow path length of the fluid flow path 40 becomes longer, the viscous resistance acting on the air flowing out through the fluid flow path 40 increases, and the air flows out of the fluid flow path 40. It becomes difficult to do. That is, the interval between the piston 22 and the cylinder 12 is difficult to shrink.
By such a function, a response to a swing in the direction in which the cylinder side member 10 is raised is delayed, and an overshoot of a response to the input swing is suppressed.

Further, when the position of the cylinder side member 10 is lowered due to the shaking of the earthquake, the pressure of the supplied air remains unchanged, and the weight of the building body is temporarily reduced. For this reason, the piston 22 and the cylinder 12 are displaced toward the equilibrium position with the reduced weight, and the amount of air flowing out through the fluid flow path 40 is reduced.
However, when the piston 22 and the cylinder 12 are separated, the overlap between the piston 22 and the cylinder 12 becomes smaller than that in the standby state (equilibrium position).
When the overlap between the piston 22 and the cylinder 12 is reduced, the viscous resistance acting on the air flowing out through the fluid flow path 40 is reduced, and the air easily flows out from the fluid flow path 40. That is, the interval between the piston 22 and the cylinder 12 is easily contracted. And since the weight of a building main body is applied to the piston 22, the expansion of a space | interval is suppressed.
By such an action, a delay occurs in the response to the swing in the direction in which the cylinder side member 10 is lowered, and an overshoot of the response to the input is suppressed.
With the above-described function, the seismic isolation device 1 behaves as if it has a spring material with a small spring constant and absorbs shaking.

Next, the effect of the seismic isolation apparatus 1 of this embodiment is demonstrated.
In the present embodiment, air as a working fluid composed of a viscous fluid is not sealed but is supplied to the cylinder 12 at a predetermined pressure and flows out of the cylinder 12, so that the air is not shaken in a standby state. The building body as a supported object can be supported in an equilibrium position with a pressure of.
In addition, in a vibration absorbing state in which a vibration such as an earthquake is input and the piston 22 reciprocates, the air behaves like a spring having a small spring constant, and the natural frequency formed by the supported object and the seismic isolation device 1 is reduced. It can absorb shaking while lowering.

Moreover, in this embodiment, since the working fluid is air, it does not affect the surrounding environment even if it is not collected after flowing out of the fluid flow path 40. And the air supplied in the cylinder 12 can be collected from the circumference | surroundings of an apparatus.
Thus, since it is not necessary to provide a recovery means for circulating the working fluid, the entire apparatus can be reduced in size and cost.

In the present embodiment, an orifice 15 is disposed in the supply pipe 14. Air as a working fluid is supplied into the cylinder 12 from a compressor (not shown) through a supply pipe 14 and an orifice 15 in a choked flow state. The flow rate of the air supplied into the cylinder 12 is constant because it is a choke flow.
The choke flow is a flow that has reached a critical state with Mach number M = 1 due to a restriction such as the orifice 15. In the choke flow, even if the pressure difference across the orifice 15 is further increased, the flow rate cannot be increased any more, so the flow rate becomes constant.
As described above, the supply amount of air can be made constant with a relatively simple configuration in which the orifice 15 whose inner diameter is set to a predetermined dimension is arranged in the supply pipe 14.
As a result, the configuration of the entire apparatus and the operation method can be simplified, and higher reliability can be exhibited.

In the present embodiment, the provision of the guide mechanism 30 can prevent a collision with the cylinder 12 due to a swing in the radial direction when the piston 22 reciprocates.
As a result, when the piston 22 reciprocates, the cylinder 12 is not twisted, the vibration can be absorbed with a smoother motion, and the seismic isolation performance can be further improved.

Moreover, by setting it as the structure of the seismic isolation apparatus 1 of this embodiment, it is not necessary to switch an operation mode with a standby state and a vibration absorption state. In other words, by keeping the seismic isolation device 1 always in operation, it is possible to absorb vibrations without a short cut for sudden earthquakes. This makes it possible to simplify the overall configuration and operation method of the device, Higher reliability can be exhibited.

In the present embodiment, the cylinder side member 10 is fixed to the foundation portion of the building on the ground side, and the piston side member 20 is arranged to be fixed to the building body on the supported object side. However, the present invention is not limited to such a form.
For example, with respect to the arrangement of the first embodiment, the piston side member 20 is fixed to the foundation portion of the building on the ground side, and the cylinder side member 10 is fixed to the building main body on the supported object side. It can also be placed upside down.
Even when arranged in such a form, the same effect as the above-described configuration can be obtained. Moreover, it becomes easy to arrange | position the compressor outside a figure to the building main body side by arrange | positioning with such a form.
As a result, since the compressed air can be stably supplied into the cylinder 12 even in the midst of shaking with a large seismic intensity, the reliability of the seismic isolation device 1 can be further improved.

Moreover, although the seismic isolation apparatus 1 of this embodiment is arrange | positioned between the foundation part of a building and a building main body so that the shaking of a building main body may be interrupted | blocked, it is not limited to such a form. Absent.
For example, by installing the downsized seismic isolation device 1 of the present embodiment in a room of a building that is not seismically isolated to support the articles placed in the room and to block the shaking from the building against the articles. Is also possible.

Moreover, in the above-described operation method, the seismic isolation device 1 has always been operated, but is not limited to such an operation method.
For example, as another operation method, in a standby state, the supply of air is stopped and the building body is supported in a state as shown in FIG. Then, it is possible to take an operation method such as receiving an emergency earthquake bulletin, etc., and starting the supply of air immediately before the occurrence of the earthquake so that the state shown in FIG. 2 is obtained.

<Another aspect of the first embodiment>
Next, a first embodiment of the present invention will be described in detail with reference to the drawings. In the description, the same components as those in the first embodiment described above are denoted by the same reference numerals, and redundant description is omitted.
As shown in FIGS. 4 (a) and 4 (b), the greatly different configuration between the seismic isolation device 1a of the present embodiment and the seismic isolation device 1 of the first embodiment described above is the cross section of the cylinder 12a and the piston 22a. Shape.
In the first embodiment described above, as shown in FIG. 2B, the cross-sectional shapes of the cylinder 12a and the piston 22a are both circular.
However, in this embodiment, the cylinder 12a has a shape like an internal gear, and the piston 22a has a shape like an external gear. Then, the piston 22a is inserted into the cylinder 12a with a predetermined interval so that the spline shaft is fitted.
By setting it as a form like this aspect, since the area which the cylinder 12a and piston 22a oppose can be expanded, viscous resistance can be made to act more strongly.
As a result, the viscous resistance can be applied more strongly without replacing the working fluid with another substance.

Second Embodiment
Next, a second embodiment of the present invention will be described in detail with reference to the drawings. In the description, the same components as those in the first embodiment described above are denoted by the same reference numerals, and redundant description is omitted.
As shown in FIGS. 5 and 6 (a) to 6 (c), the greatly different configuration between the seismic isolation device 1 </ b> A of the present embodiment and the seismic isolation device 1 of the first embodiment described above is It is the point provided with the closing mechanism 50 which opens and closes.
The closing mechanism 50 includes a closing member 51 and a closing means 52.
The closing member 51 has an annular shape, and the closing circular hole 51a opened in the center has a hole diameter D51a set to be substantially the same as the piston outer diameter D22. And the closing member 51 does not rattle on the outer peripheral surface of the piston 22, and is between a closing position (see FIG. 6 (a)) described later and an opening position (see FIG. 6 (b)) described later. It is arranged to be freely movable along the axial direction. The closing member 51 is provided with a seal portion 51b at the edge of the closing circular hole 51a.
The seal portion 51b is formed of a semicircular protrusion, and in a state where the closing member 51 is held at the closed position, the seal portion 51b is pressed against the outlet of the fluid passage 40 and seals the outlet of the fluid passage 40.

The closing means 52 includes a closing cylinder 53 and a closing piston 54.
The closing cylinder 53 has a cylindrical shape with one end on the ground side closed, and is disposed outside the cylinder 12 in parallel with the cylinder 12. In addition, operating pipes 55 are connected to both ends of the closing cylinder 53.
The working pipe 55 has a flange side set as a closed side working pipe 55a and a cylinder base side set as an open side working pipe 55b.
The closing piston 54 has a disk shape having an outer diameter substantially the same as the inner diameter of the closing cylinder 53. The closing piston 54 is arranged to be freely movable while dividing the inside of the closing cylinder 53 into two regions in the axial direction.
In the closing mechanism 50 having such a configuration, the closing piston 54 reciprocates in the closing cylinder 53 so that the closing member 51 connected to the closing piston 54 via the piston shaft 56 is in a closed position and an open position. And the outlet of the fluid flow path 40 is opened and closed.

In the standby state (closed position), as shown in FIG. 6A, the inside of the open side working tube 55b is depressurized or opened to the atmosphere while the inside of the close side working tube 55a is pressurized. Then, due to the differential pressure between the closing side working tube 55a and the opening side working tube 55b, the closing piston 54 moves to the opening side working tube 55b side (the lower side in the figure), and the closing member 51 is moved to the outlet of the fluid flow path 40. Is pressed and sealed.
In the vibration absorbing state (open position), the inside of the closing cylinder 53 is opened to the atmosphere as shown in FIG. When the atmosphere is released, the closing member 51 is moved to the open position by the pressure of the air in the fluid flow path 40, and the fluid flow path 40 is opened.
Switching between the standby state and the vibration absorption state is performed at a timing when, for example, an earthquake early warning is received and a vibration from the epicenter arrives several seconds later.

The closed position is a position where the closing member 51 closes the outlet of the fluid flow path 40 and prevents or suppresses the outflow of air from the cylinder 12 as shown in FIG.
The open position is a position where the closing member 51 opens the outlet of the fluid flow path 40 and allows the air to flow out from the cylinder 12. And the closing member 51 located in an open position is located between the flange 13 and the piston base 21, and is displaced with the cylinder side member 10, as shown in FIG.6 (b).
Moreover, it is also possible to set a different open position at a position as shown in FIG. In the open position, the inside of the open side working tube 55b is pressurized while the inside of the closing side working tube 55a is opened to the atmosphere. The closing member 51 is brought into contact with the piston base 21 and displaced together with the piston side member 20 by the differential pressure between the closing side working tube 55a and the opening side working tube 55b.

In the present embodiment, at the time of standby when no earthquake occurs, as shown in FIG. 6A, the closing member 51 is held at the closing position to prevent outflow of air as the working fluid from the cylinder 12. Further, when an earthquake occurs (swing absorption state), the closing member 51 is moved to the open position as shown in FIG.
By enabling such an operation method, the supply of air can be stopped during standby.
Thereby, the operation cost for supplying air into the cylinder 12 can be reduced, and the seismic isolation device 1 can be operated at low cost.

It should be noted that the amount of work required to maintain the state where the outlet of the fluid flow path 40 is closed by the closing member 51 can be negligible compared to the amount of work in which air is continuously supplied at a predetermined pressure. This is because the distance between the piston 22 and the cylinder 12 is very small compared to the cylinder inner diameter D12.
Therefore, the closing means 52 used for holding the closing member 51 in the closing position can be smaller in diameter than the cylinder 12.
In addition, in the present embodiment, the cylinder 12 is in a state of being filled with air at a predetermined pressure in comparison with the operation method in which the supply of air is started immediately before the shake from the epicenter arrives. , Can respond quickly to earthquakes.

<Third Embodiment>
Next, a third embodiment of the present invention will be described in detail with reference to the drawings. In the description, the same components as those in the first embodiment described above are denoted by the same reference numerals, and redundant description is omitted.
As shown in FIG. 7, the greatly different configuration between the seismic isolation device 1 </ b> B of the present embodiment and the seismic isolation device 1 of the first embodiment described above is that an air tank 60 is provided.
The air tank 60 has a substantially box shape with a predetermined volume, and is disposed outside the cylinder 12. In addition, the air tank 60 communicates with the inside of the cylinder 12 so that air can freely come and go.
By providing such an air tank 60, it is possible to absorb sudden shaking and vibration by compressing and expanding the air in the air tank 60.
Thereby, the seismic isolation performance can be further enhanced.
Note that the inside of the cylinder 12 is opened to the atmosphere through the fluid flow path 40. For this reason, the air is compressed and expanded, and after absorbing the vibration, the air converges to the pressure of the supplied air without repeating the vibrations of expansion and compression. That is, the air tank 60 functions as a spring having a smaller spring constant than an air spring having a constant volume.

<Another aspect of the third embodiment>
Next, another aspect of the third embodiment of the present invention will be described in detail with reference to the drawings. In the description, the same components as those in the third embodiment described above are denoted by the same reference numerals, and redundant description is omitted.
As shown in FIG. 8, a greatly different configuration between the seismic isolation device 1Ba of this aspect and the seismic isolation device 1B of the third embodiment described above is the configuration of the air tank 60Ba.
The air tank 60Ba of this aspect is formed inside the piston 22.
By forming the air tank 60Ba inside the piston 22 as in this aspect, the entire apparatus is simplified and lighter than the form in which the air tank 60 is disposed outside the cylinder 12 as in the third embodiment. can do.
Moreover, by setting it as the form of this aspect, even if the space where the seismic isolation apparatus 1 is installed is narrow and the air tank 60 cannot be installed outside the cylinder 12, the air tank 60Ba can be installed.

Furthermore, since the air tank 60Ba can be formed inside the piston 22, the air tanks 60 and 60Ba can be installed on both the cylinder side member 10 and the piston side member 20.
Thereby, even if the member installed in the foundation part side of a building is either the cylinder side member 10 or the piston side member 20, the structure of the member arrange | positioned at the foundation part side of a building is simplified more. It is possible to perform stable operation against tremors with large seismic intensity.

<Fourth embodiment>
Next, a fourth embodiment of the present invention will be described in detail with reference to the drawings. In the description, the same components as those in the first embodiment described above are denoted by the same reference numerals, and redundant description is omitted.
As shown in FIGS. 9 (a) and 9 (b), the greatly different configuration between the seismic isolation device 1C of this embodiment and the seismic isolation device 1 of the first embodiment described above is a configuration that forms a fluid flow path 40C. It is.
In the present embodiment, the fluid flow path 40 </ b> C includes the cylinder 12, the piston 22, and a guide body 70 </ b> C installed between the cylinder 12 and the piston 22.
The guide body 70C has an annular outer shape, and the annular outer diameter D70a is set to substantially match the cylinder inner diameter D12, and the annular inner diameter D70b is set to match the piston outer diameter D22. It is composed of members. Further, the guide body 70 </ b> C has a plurality of flow passage holes 71 that penetrate through the annular portion along the cylinder axis direction at equal intervals in the circumferential direction.
A plurality of guide bodies 70 </ b> C are arranged on the outer periphery of the piston 22 at a predetermined interval in the cylinder axis direction, and reciprocate together with the piston 22. The viscous resistance is exhibited in a region between the guide body 70C and the guide body 70C.
That is, by installing the guide body 70 </ b> C, the viscous resistance can be adjusted by the area where the outer peripheral surface of the piston 22 and the inner peripheral surface of the cylinder 12 face each other.

By installing the guide body 70 </ b> C as in the present embodiment, the fluid flow path 40 can be formed while maintaining a predetermined distance (dimension) between the cylinder 12 and the piston 22 in the radial direction.
Therefore, when the piston 22 reciprocates, the collision with the cylinder 12 due to the vibration in the radial direction can be prevented without disturbing the flow of the working fluid.
As a result, when the piston 22 reciprocates, the cylinder 12 is not twisted, the vibration can be absorbed with a smoother motion, and the seismic isolation performance can be further improved.
Further, by installing the guide body 70C, the area where the outer peripheral surface of the piston 22 and the inner peripheral surface of the cylinder 12 face each other is smaller than when the guide body 70C is not installed, so that the action of viscous resistance is reduced. be able to.
Thereby, the action of viscous resistance can be reduced without replacing the working fluid with another substance.

<First Aspect of Fourth Embodiment>
Next, the 1st another aspect of 4th Embodiment of this invention is demonstrated in detail with reference to drawings. In the description, the same components as those in the above-described fourth embodiment are denoted by the same reference numerals, and redundant description is omitted.
As shown in FIG. 10, the structure which is greatly different between the seismic isolation device 1Ca of this aspect and the seismic isolation device 1 of the above-described fourth embodiment is the configuration of the guide body 70Ca.
In this aspect, a cylindrical guide body 70Ca is disposed instead of the annular guide body 70C.
The guide body 70Ca of this aspect is fixed in the cylinder 12 with the outer diameter D70a being set to be the same as the cylinder inner diameter D12 and the inner diameter D70b being set to be substantially the same as the piston outer diameter D22. The guide body 70Ca has a plurality of rectangular grooves 72 along the cylinder axis direction formed on the inner peripheral surface thereof, and a fluid flow path 40Ca is formed by the rectangular grooves 72 and the outer peripheral surface of the piston 22. . The guide body 70Ca is in a state where the inner peripheral surface of the guide body 70Ca is fixed in the cylinder 12 when the piston 22 reciprocates, and the inner peripheral surface thereof is in sliding contact with the outer peripheral surface of the piston 22.
Even in the case of the form of the guide body 70Ca of this aspect, the same effect as that of the above-described fourth embodiment can be obtained.

<Second Second Aspect of Fourth Embodiment>
Next, a second different aspect of the fourth embodiment of the present invention will be described in detail with reference to the drawings. In the description, the same components as those in the above-described fourth embodiment are denoted by the same reference numerals, and redundant description is omitted.
As shown in FIG. 11, a greatly different configuration between the seismic isolation device 1Cb of this aspect and the above-described seismic isolation device 1 of the fourth embodiment is the configuration of the guide body 70Cb.
In this aspect, a cylindrical guide body 70Cb is arranged instead of the annular guide body 70C.
The guide body 70 </ b> Cb of this aspect has an outer diameter D <b> 70 a set substantially the same as the cylinder inner diameter D <b> 12, while an inner diameter D <b> 70 b is set the same as the piston outer diameter D <b> 22 and is fixed to the outer periphery of the piston 22. The guide body 70Cb has a plurality of trapezoidal grooves 73 along the cylinder axis direction formed on the inner peripheral surface thereof, and a fluid flow path 40Cb is formed by the trapezoidal groove 73 and the inner peripheral surface of the cylinder 12. Yes. The guide body 70 </ b> Cb is slidably contacted with the inner peripheral surface of the cylinder 12 in a state of being fixed in the cylinder 12 when the piston 22 reciprocates.
Even in the case of the guide body 70Cb of this aspect, the same effects as those of the above-described fourth embodiment can be obtained.

DESCRIPTION OF SYMBOLS 1 Seismic isolation device 12 Cylinder 22 Piston 30 Guide mechanism 40 Fluid flow path 51 Closing member 60 Air tank 70C Guide body

Claims (7)

A cylinder having one end closed and a cylinder installed on either the ground side or the supported object side;
A piston configured to be relatively displaceable in the cylinder axis direction inside the cylinder, and installed on the other of the ground side and the supported object side;
A fluid flow path communicating between the inside of the cylinder and the outside of the cylinder between the cylinder and the piston in the radial direction;
A working fluid consisting of a viscous fluid and flowing out of the cylinder through the fluid flow path while being supplied to the inside of the cylinder at a predetermined pressure;
A seismic isolation device comprising: The working fluid is
The seismic isolation device according to claim 1, comprising air. The working fluid is
The seismic isolation device according to claim 2, wherein the seismic isolation device is supplied into the cylinder in a choke flow state. The seismic isolation device according to claim 2, further comprising an air tank having a predetermined volume and communicating with the inside of the cylinder. 5. The device according to claim 1, further comprising a closing member that is movable between a closing position that closes the fluid flow path and an open position that opens the fluid flow path. Seismic isolation device. A guide mechanism is provided that supports a relative displacement in the axial direction between the piston and the cylinder while restricting a relative displacement in the radial direction between the piston and the cylinder. The seismic isolation apparatus of any one of Claims 1-5. 7. The guide body according to claim 1, further comprising a guide body that forms the fluid flow path while maintaining a predetermined distance between the cylinder and the piston in a radial direction. Seismic isolation device.

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