Seismic isolation structure

Abstract

To provide a base isolation structure capable of executing an effective minute vibration countermeasure.SOLUTION: The base-isolated S10 includes a base-isolating device provided on a lower structural body 12 and supporting an upper structural body 14 in a base-isolated manner, and a damping member 18 for microvibration provided between the lower structural body 12 and the upper structural body 14. The damping member 18 for minute vibration includes the cylindrical body 32 fixed to the upper surface of the lower structure 12, the core member 34 disposed in the cylindrical body 32, the viscous body 36 provided on the bottom side inside the cylindrical body 32 and configured to come into contact with the lower end portion of the core member 34 to apply a damping force to the core member 34, and the lid body 38 provided at the mouth portion of the cylindrical body 32 and formed with the through hole through which the core member 34 penetrates. And a main shaft material 44 having the other end connected to the upper structure 14 by a universal joint and converting vertical and horizontal microvibration into the axial movement of the core material 34.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a seismic isolation structure. [Background technology]

[0002] Patent Document 1 below discloses a seismic isolation device. This seismic isolation device is provided with an elastic sliding bearing in which a fixed sliding plate is attached to a lower footing, and a laminated rubber bearing with a sliding member that comes into contact with the sliding plate is attached to an upper footing. This seismic isolation device is also provided with a micro-vibration oil damper, one end of which is attached to a support provided on the upper footing, and the other end of which is connected to a mounting member provided on the sliding member side. Two micro-vibration oil dampers are arranged on both sides of the laminated rubber, with their axes aligned along the sliding plate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-281559 Summary of the Invention [Problem to be solved by the invention]

[0004] The seismic isolation device described in Patent Document 1 does not exhibit different characteristics during normal times to counter micro-vibrations and during earthquakes. Therefore, it is unclear how effectively the micro-vibration oil damper functions to counter micro-vibrations both during normal times and during earthquakes.

[0005] In consideration of the above, an object of the present invention is to provide a seismic isolation structure that can effectively counter micro-vibrations. [Means for solving the problem]

[0006] The seismic isolation structure described in the first aspect comprises a seismic isolation device provided on a lower structure for seismically supporting an upper structure, and a micro-vibration damping member provided between the lower structure and the upper structure, wherein the micro-vibration damping member comprises a cylindrical body fixed to the upper surface of the lower structure or the lower surface of the upper structure, a core material disposed within the cylindrical body, a viscous body provided on the bottom or upper side of the interior of the cylindrical body in contact with one end of the core material to apply a damping force to the core material, a lid body provided at the mouth of the cylindrical body and having a through hole through which the core material passes, and a main shaft member having one end connected to the other end of the core material by a universal joint and the other end connected to the upper structure or the lower structure by a universal joint, and converting vertical and horizontal micro-vibrations into axial movement of the core material.

[0007] According to the seismic isolation structure of the first aspect, one end of the core material constituting the micro-vibration damping member is normally in contact with the viscous material inside the cylindrical body. When the lower structure or upper structure vibrates to a degree that does not activate the seismic isolation device, that is, when the lower structure or upper structure undergoes relative vertical or horizontal displacement, the main shaft moves vertically or horizontally accordingly. As a result, as the core material moves in the axial direction, the viscous material applies a damping force to the core material, enabling the micro-vibration of the upper structure to be suppressed via the main shaft. Furthermore, during an earthquake, the seismic isolation device operates, suppressing the shaking of the upper structure. Furthermore, when an earthquake occurs and the seismic isolation device is activated, one end of the core material escapes from the viscous material inside the cylindrical body, so that the core material is free and no damping force is applied to it. Therefore, the micro-vibration damping member does not restrict the function of the seismic isolation device during an earthquake.

[0008] The seismic isolation structure described in the second aspect is the seismic isolation structure described in the first aspect, which has a guide plate attached to the core material and sliding on the inner surface of the cylindrical body, and when one end of the core material is released from the viscous body inside the cylindrical body, the guide plate comes into contact with the lid body, thereby restricting the vertical movement of the core material.

[0009] According to the seismic isolation structure of the second aspect, the guide plate comes into contact with the cover, thereby providing the micro-vibration damping member with a stopper function, and making it possible to suppress excessive deformation of the upper structure. Furthermore, when the core material is released from the viscous material inside the cylindrical body, the guide plate comes into contact with the lid body, thereby creating a structure in which the damping effect of the micro-vibration damping member does not work during an earthquake.

[0010] A seismic isolation structure according to a third aspect is the seismic isolation structure according to the first aspect, wherein the viscous material is oil.

[0011] According to the seismic isolation structure of the third aspect, by using oil with a higher viscosity than water, it is possible to obtain a damping effect against micro-vibrations.

[0012] The seismic isolation structure described in the fourth aspect is the seismic isolation structure described in the first aspect, wherein the lower part of the micro-vibration damping member in the vertical direction is fixed to the lower structure, the cylindrical body is fixed to the upper surface of the lower structure, the viscous body is provided on the bottom side inside the cylindrical body, and the other end of the main shaft material is connected to the upper structure by a universal joint.

[0013] According to the seismic isolation structure of the fourth aspect, the cylindrical body of the micro-vibration damping member is fixed to the upper surface of the lower structure, and the viscous body is provided on the bottom side inside the cylindrical body. Therefore, the micro-vibration damping member is easier to manufacture than when the cylindrical body is fixed to the underside of the upper structure. [Effects of the Invention]

[0014] According to the seismic isolation structure of the present disclosure, effective countermeasures against micro-vibrations can be implemented. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a front view showing a seismic isolation structure of a first embodiment. [Figure 2] FIG. 2 is a front view showing a micro-vibration damping member in the seismic isolation structure of the first embodiment. [Figure 3]3 is a perspective view showing a cylindrical body, a part of a core material, and a viscous body of the micro-vibration damping member. FIG. [Figure 4] 3 is a cross-sectional view showing a cylindrical body, a part of a core material, and a viscous body of a micro-vibration damping member. FIG. [Figure 5] 4, (B) is a cross-sectional view taken along line 5B-5B in FIG. 4, and (C) is a cross-sectional view taken along line 5C-5C in FIG. [Figure 6] 1A is a front view showing the seismic isolation structure in normal operation, and FIG. 1B is a cross-sectional view showing the operating state of the lower side of the micro-vibration damping member in normal operation. [Figure 7] 1A is a front view showing the seismic isolation structure during an earthquake (assumed), and FIG. 1B is a cross-sectional view showing the operating state of the lower side of the micro-vibration damping member during an earthquake (assumed). [Figure 8] 1A is a front view showing the seismic isolation structure after an earthquake, and FIG. 1B is a cross-sectional view showing the state of the lower side of the micro-vibration damping member after the earthquake. [Figure 9] 1A is a front view showing the seismic isolation structure during an earthquake (unexpected), and FIG. 1B is a cross-sectional view showing the operating state of the lower side of the micro-vibration damping member during an earthquake (unexpected). DETAILED DESCRIPTION OF THE INVENTION

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the accompanying drawings, in which elements less relevant to the present invention are omitted.

[0017] [First embodiment] The base isolation structure of the first embodiment will be described with reference to Figures 1 to 9. Figure 1 shows a front view of the overall configuration of a base isolation structure S10 of the first embodiment.

[0018] <Overall structure of the seismic isolation structure> As shown in Figure 1, the seismic isolation structure S10 includes a seismic isolation device 16 provided on the lower structure 12 to provide seismic support for the upper structure 14, and a micro-vibration damping member 18 provided between the lower structure 12 and the upper structure 14.

[0019] The lower structure 12 is fixed to the ground 20. The lower structure 12 is, for example, a concrete foundation. As an example, the lower structure 12 includes a lower structure portion 12A provided below the upper structure 14, an upright portion 12B that rises from the lower structure portion 12A, and an upper structure portion 12C that is connected to the upright portion 12B and is positioned higher than the lower structure portion 12A. The shape of the lower structure 12 can be changed.

[0020] The upper structure 14 is a building. The structure and use of the building are not particularly limited. The upper structure 14 may be, for example, a multi-story building. Furthermore, the upper structure 14 may be, for example, a semiconductor production facility that is sensitive to micro-vibrations.

[0021] <Configuration of seismic isolation device> As shown in FIG. 1 , the seismic isolation device 16 includes a lower mounting plate 22 fixed to the upper surface of the lower structure 12, an upper mounting plate 24 fixed to the lower surface of the upper structure 14, and an elastic layer 26 disposed between the lower mounting plate 22 and the upper mounting plate 24. The lower mounting plate 22 is fixed to the upper surface of the lower structure 12 with anchor bolts (not shown) or the like. The upper mounting plate 24 is fixed to the lower surface of the upper structure 14 with anchor bolts (not shown) or the like. The elastic layer 26 is made of laminated rubber, for example, in which rigid layers such as steel plates and rubber layers are alternately laminated. The lower surface of the elastic layer 26 is bonded to the lower mounting plate 22. The upper surface of the elastic layer 26 is bonded to the upper mounting plate 24.

[0022] The seismic isolation device 16 is provided on the lower structure 12 and supports the upper structure 14 in a seismic isolation manner, thereby making it difficult for horizontal vibrations caused by earthquakes to be transmitted to the upper structure 14.

[0023] <Configuration of Micro-Vibration Damping Member> Fig. 2 shows a front view of the micro-vibration damping member 18. As shown in Fig. 2, the micro-vibration damping member 18 has a vertical lower portion fixed to the lower structure 12. Specifically, the micro-vibration damping member 18 includes a cylindrical body 32 fixed to the upper surface of the lower structure 12, a core material 34 disposed within the cylindrical body 32, and a viscous body 36 provided on the bottom side of the interior of the cylindrical body 32. The micro-vibration damping member 18 also includes a lid body 38 provided at the opening 32A of the cylindrical body 32. The micro-vibration damping member 18 further includes a main shaft 44 having one end 44A connected to the core material 34 by a universal joint 40 and the other end 44B connected to the upper structure 14 by a universal joint 42.

[0024] Fig. 3 is a perspective view showing the vicinity of the cylindrical body 32 and core material 34 of the micro-vibration damping member 18. Fig. 4 is a cross-sectional view showing the vicinity of the cylindrical body 32 and core material 34 of the micro-vibration damping member 18.

[0025] As shown in FIGS. 2 to 4, the tubular body 32 is joined to a mounting plate 52 fixed to the upper surface of the lower structure 12. The mounting plate 52 is fixed to the upper surface of the lower structure 12 with, for example, anchor bolts (not shown). The tubular body 32 is made of, for example, metal. The tubular body 32 is, for example, a cylindrical member, and the inner diameter of the tubular body 32 is larger than the outer diameter of the core material 34. In other words, the tubular body 32 is an outer cylinder that surrounds the lower side of the core material 34.

[0026] The core material 34 is, for example, a cylindrical member. A lower end portion 34A of the core material 34 in the axial direction is in contact with the viscous body 36 on the bottom side inside the cylindrical body 32. The lower end portion 34A of the core material 34 is an example of one end portion of the core material 34.

[0027] In the normal state of the micro-vibration damping member 18 (see FIG. 2), the core material 34 is arranged in the vertical direction on an extension of the main shaft material 44, which is arranged in the vertical direction, via the universal joint 40. In this state, the lower end portion 34A of the core material 34 is configured not to come into contact with the mounting plate 52. In other words, a gap is formed between the lower end portion 34A of the core material 34 and the mounting plate 52.

[0028] A guide plate 54 is attached to the axial middle of the core material 34. The guide plate 54 is a circular ring-shaped body joined to the outer circumferential surface of the core material 34 (see FIGS. 3 and 5(B)). The outer diameter of the guide plate 54 is slightly smaller than the inner diameter of the cylindrical body 32 (see FIG. 5(B)). As a result, when the core material 34 moves up and down, the guide plate 54 slides on the inner circumferential surface of the cylindrical body 32, thereby guiding the core material 34.

[0029] The viscous material 36 is filled into the bottom side of the interior of the cylindrical body 32 by gravity. The degree of viscosity of the viscous material 36 is determined by whether it can absorb external energy by converting the energy into heat in the viscous material 36. Here, viscosity is a numerical value that indicates the stickiness of a liquid; a liquid with low viscosity flows easily, while a liquid with high viscosity flows less easily. The viscous material 36 applies a damping force to the core material 34 by contacting the lower end 34A of the core material 34 (see Figures 4 and 5(C)). The damping force is adjusted by the viscosity of the viscous material 36 and the contact area with the core material 34.

[0030] The viscous body 36 may be made of, for example, a viscous polymer material or synthetic hydrocarbon. In the first embodiment, an oil such as silicone oil is used as the viscous body 36. The viscosity of the oil constituting the viscous body 36 is higher than that of water. In the seismic isolation structure S10, the core material 34 moves in the axial direction (direction of arrow A) with the portion where the core material 34 is in contact with the viscous body 36 as a displacement region (see FIG. 6(B)). Therefore, it is possible to apply a damping force to the core material 34 by deformation of the viscous body 36.

[0031] The lid 38 is provided at the opening 32A at the top of the cylindrical body 32. The lid 38 is a circular plate material and is joined to the inner peripheral surface of the opening 32A of the cylindrical body 32. A through hole 39 is formed in the lid 38, through which the core material 34 passes. The through hole 39 is provided in the center of the lid 38. The outer diameter of the core material 34 is slightly smaller than the inner diameter of the through hole 39 (see FIGS. 4 and 5(A)). The core material 34 is movable in the vertical direction while passing through the through hole 39 of the lid 38. Furthermore, since there is a small gap between the outer peripheral surface of the core material 34 and the inner peripheral surface of the through hole 39, the core material 34 can also move slightly in the horizontal direction. For this reason, the core material 34 may be tilted obliquely so as to intersect with the vertical direction.

[0032] In the micro-vibration damping member 18, when the lower end 34A of the core material 34 is released from the viscous material 36 inside the cylindrical body 32, the guide plate 54 comes into contact with the lid body 38, thereby restricting the vertical movement of the core material 34 (see Figure 9(B)).

[0033] As shown in Fig. 2, the main shaft 44 is a rod-shaped member that is long in the axial direction. One end 44A of the main shaft 44 is connected to the upper end 34B of the core 34 by a universal joint 40. The upper end 34B of the core 34 is an example of the other end of the core 34. The other end 44B of the main shaft 44 is connected to a protrusion 62 fixed to the upper structure 14 by the universal joint 42. As an example, the protrusion 62 is joined to a mounting plate 64 fixed to the upper structure 14.

[0034] As an example, the universal joint 40 and the universal joint 42 are configured to be symmetrical in the up-down direction. A universal joint is also called a universal joint, and refers to a joint in which the angle at which two members are joined can be freely changed. In other words, a universal joint can bend two members connected to the universal joint up and down and left and right. In the first embodiment, the universal joint 40 can freely change the angle between the main shaft member 44 and the core member 34. Furthermore, the universal joint 42 can freely change the angle between the main shaft member 44 and the protrusion 62.

[0035] As an example, the universal joints 40, 42 include a spherical portion 66 and a receiving portion 68 that receives the spherical portion 66. The configuration of the universal joints 40, 42 is not limited as long as the angle at which the two members are joined can be freely changed, and joints of other shapes may also be used.

[0036] One end 44A of the main shaft 44 is connected to the upper end 34B of the core material 34 by a universal joint 40, and the other end 44B of the main shaft 44 is connected to the protrusion 62 of the upper structure 14 by a universal joint 42, so that the main shaft 44 can convert micro-vibrations in the vertical and horizontal directions into axial movement of the core material 34.

[0037] <Action and effect> Next, the operation and effects of the first embodiment will be described.

[0038] FIG. 6(A) is a front view showing the seismic isolation structure S10 in a normal state, and FIG. 6(B) is a cross-sectional view showing a part of the micro-vibration damping member 18 in a normal state.

[0039] As shown in Figure 6(A), when a vehicle 120 travels on top of the lower structure 12, micro-vibrations are transmitted to the surrounding area. As shown in Figure 6(B), the lower end 34A of the core material 34 constituting the micro-vibration damping member 18 is normally in contact with the viscous material 36 inside the cylindrical body 32. When the lower structure 12 or the upper structure 14 vibrates to an extent that does not activate the seismic isolation device 16, that is, when the lower structure 12 or the upper structure 14 undergoes relative vertical or horizontal displacement, the main shaft 44 follows and moves vertically or horizontally. One end 44A of the main shaft 44 is connected to the upper end 34B of the core material 34 by a universal joint 40, and the other end 44B is connected to the upper structure 14 by a universal joint 42, converting vertical and horizontal micro-vibrations into axial movement of the core material 34. As a result, when the core material 34 moves in the axial direction (direction of arrow A), the core material 34 is imparted with a damping force from the viscous body 36, and micro-vibrations of the upper structure 14 can be suppressed via the main shaft material 44.

[0040] Although not shown in the figures, the base isolation structure of the comparative example may use an oil damper during an earthquake, but because there may be rattle during installation of the oil damper, it is not necessarily possible to provide effective damping performance against micro-vibrations. In contrast, in the base isolation structure S10 of this embodiment, with respect to micro-vibrations, the core material 34 moves in the axial direction (direction of arrow A) with the portion where the core material 34 is in contact with the viscous material 36 as a displacement region, and therefore it is possible to apply a damping force to the core material 34 due to deformation of the viscous material 36. Therefore, in the base isolation structure S10, the micro-vibration damping member 18 can be used to implement effective countermeasures against micro-vibrations.

[0041] Furthermore, in the seismic isolation structure S10, a guide plate 54 that slides on the inner peripheral surface of the cylindrical body 32 is attached to the core material 34. Therefore, the guide plate 54 can guide the movement of the core material 34 in the axial direction (direction of arrow A).

[0042] In the seismic isolation structure S10, the viscous body 36 is oil. By using oil, which has a higher viscosity than water, as the viscous body 36, it is possible to obtain a damping effect against micro-vibrations.

[0043] Furthermore, in the seismic isolation structure S10, the lower portion of the micro-vibration damping member 18 in the vertical direction is fixed to the lower structure 12. The cylindrical body 32 is fixed to the upper surface of the lower structure 12, and the viscous body 36 is provided on the bottom side inside the cylindrical body 32. Furthermore, the other end 44B of the main shaft member 44 is connected to the upper structure 14 side by a universal joint 42. For this reason, in the seismic isolation structure S10, the micro-vibration damping member 18 is easier to manufacture than when the cylindrical body is fixed to the underside of the upper structure.

[0044] FIG. 7(A) is a front view showing the seismic isolation structure S10 during an earthquake (assumed), and FIG. 7(B) is a cross-sectional view showing a part of the micro-vibration damping member 18 during an earthquake (assumed).

[0045] As shown in Figure 7(A), during an earthquake (within the expected range), the lower structure 12 and the upper structure 14 are displaced relative to each other. In the seismic isolation structure S10, the seismic isolation device 16 is provided on the lower structure 12 and supports the upper structure 14 in a seismic isolation manner. During an earthquake, the seismic isolation device 16 operates to damp horizontal vibrations caused by the earthquake, thereby suppressing the shaking of the upper structure 14.

[0046] As shown in Figure 7(B), in the event of an earthquake that activates the seismic isolation device 16, the micro-vibration damping member 18 is configured so that the lower end 34A of the core material 34 moves upward (in the direction of arrow B) and escapes from the viscous material 36 inside the cylindrical body 32, leaving the core material 34 free and without any damping force being applied to it. Therefore, the micro-vibration damping member 18 does not restrict the function of the seismic isolation device 16 during an earthquake.

[0047] Furthermore, a guide plate 54 that slides on the inner circumferential surface of the cylindrical body 32 is attached to the core 34, and can guide the movement of the core 34 upward (in the direction of arrow B).

[0048] FIG. 8(A) is a front view showing the seismic isolation structure S10 after an expected earthquake, and FIG. 8(B) is a cross-sectional view showing a part of the micro-vibration damping member 18 after the expected earthquake.

[0049] As shown in Figures 8(A) and (B), after an expected earthquake, the core material 34 of the micro-vibration damping member 18 returns to its original position as the elastic layer 26 of the seismic isolation device 16 moves. The lower end portion 34A of the core material 34 then comes into contact with the viscous material 36 inside the cylindrical body 32. As a result, in the seismic isolation structure S10, when micro-vibrations act under normal conditions, the core material 34 moves in the axial direction, and the viscous material 36 imparts a damping force to the core material 34, thereby suppressing micro-vibrations of the upper structure 14 via the main shaft 44. Therefore, in the seismic isolation structure S10, the micro-vibration damping member 18 can be used to implement effective countermeasures against micro-vibrations.

[0050] FIG. 9(A) is a front view showing the seismic isolation structure S10 during an earthquake (unexpected), and FIG. 9(B) is a cross-sectional view showing a part of the micro-vibration damping member 18 during an earthquake (unexpected).

[0051] As shown in Figure 9(A), during an earthquake (unexpected), the lower structure 12 and the upper structure 14 will undergo a large relative displacement. As shown in Figure 9(B), in the micro-vibration damping member 18, a guide plate 54 that slides on the inner circumferential surface of the cylindrical body 32 is attached to the core material 34. As a result, when the lower end portion 34A of the core material 34 is released from the viscous body 36 inside the cylindrical body 32, the guide plate 54 comes into contact with the lid body 38, thereby restricting the upward movement of the core material 34 (in the direction of arrow C).

[0052] Therefore, in the seismic isolation structure S10, the guide plate 54 comes into contact with the cover body 38, thereby giving the micro-vibration damping member 18 a stopper function and making it possible to suppress excessive deformation of the upper structure 14.

[0053] Furthermore, when the core material 34 has escaped from the viscous material 36 inside the cylindrical body 32, the guide plate 54 comes into contact with the lid body 38, thereby making it possible to create a structure in which the damping effect of the micro-vibration damping member 18 does not work during an earthquake.

[0054] [Modification] Although not shown, in a modified seismic isolation structure, the micro-vibration damping member may have a vertical upper portion fixed to the upper structure. For example, the micro-vibration damping member includes a cylindrical body fixed to the underside of the upper structure, a core material disposed within the cylindrical body, and a viscous body provided on the upper side of the cylindrical body and in contact with the upper end of the core material to apply a damping force to the core material. In the modified seismic isolation structure, the lower end of the main shaft material is connected to the lower structure by a universal joint.

[0055] In the modified seismic isolation structure, for example, it is preferable to provide inside the cylindrical body a partition plate that holds the viscous material at the upper side inside the cylindrical body, and a sealing member that prevents the viscous material from leaking out.

[0056] In the modified seismic isolation structure, when the lower structure or upper structure undergoes relative displacement in the vertical or horizontal direction, the main shaft moves in the vertical or horizontal direction accordingly. As a result, the core material moves in the axial direction, and a damping force is applied to the core material by the viscous material, thereby suppressing micro-vibrations of the upper structure.

[0057] 〔others〕 In the first embodiment and the modified examples, the configurations of the guide plate 54 and the cylindrical body 32 are not limited to those disclosed herein and can be changed to other configurations. In addition, the configurations of the lower structure 12 and the upper structure 14 can be changed. The number of seismic isolation devices 16 between the lower structure 12 and the upper structure 14 and the number of micro-vibration damping members 18 can be set as appropriate.

[0058] In the first embodiment, the lower end 34A of the core material 34 comes out of the viscous material 36 inside the cylindrical body 32 during an earthquake (as expected) (see FIG. 7(B)), but the present disclosure is not limited to this configuration. For example, the lower end 34A of the core material 34 may be configured to come into contact with the viscous material 36 inside the cylindrical body 32 during an earthquake.

[0059] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that the present invention is not limited to such embodiments, and that various other embodiments are possible within the scope of the present invention. [Explanation of symbols]

[0060] S10 Seismic isolation structure 12 Undercarriage 14 Superstructure 16 Seismic isolation device 18 Micro-vibration damping material 32 Cylinder 32A Mouth 34 Viscous body 34 Core material 34A Lower end (example of one end) 34B Upper end (an example of the other end) 36 Viscous body 38 Lid 39 Through Hole 40 Universal Joint 42 Universal joint 44 Main shaft material 44A One end 44B Other end 54 Guide plate

Claims

1. a seismic isolation device provided on the lower structure for seismically isolating and supporting the upper structure; a micro-vibration damping member provided between the lower structure and the upper structure; Equipped with The micro-vibration damping member is a cylindrical body fixed to an upper surface of the lower structure or a lower surface of the upper structure; a core material disposed within the cylindrical body; a viscous body provided on a bottom side or an upper side inside the cylindrical body and in contact with one end of the core material to impart a damping force to the core material; a lid provided at an opening of the cylindrical body and having a through hole through which the core material passes; a main shaft member having one end connected to the other end of the core member by a universal joint and the other end connected to the upper structure or the lower structure by a universal joint, converting vertical and horizontal micro-vibrations into axial movement of the core member; It has a seismic isolation structure.

2. a guide plate attached to the core material and sliding on the inner circumferential surface of the cylindrical body; The seismic isolation structure described in claim 1, wherein when one end of the core material is released from the viscous material inside the cylindrical body, the guide plate contacts the cover body, thereby restricting the vertical movement of the core material.

3. The seismic isolation structure according to claim 1 , wherein the viscous material is oil.

4. The micro-vibration damping member has a lower portion in the vertical direction fixed to the lower structure, the cylindrical body is fixed to an upper surface of the lower structure, the viscous body is provided on the bottom side inside the cylindrical body, 2. The seismic isolation structure according to claim 1, wherein the other end of the main shaft member is connected to the upper structure by a universal joint.

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