Seismic isolation device

Abstract

To provide a seismic isolator which can widely optimize an attenuation force exerted by a damper to a quake having a variety of magnitudes reaching small / medium-scale earthquakes from a huge earthquake, and can reduce response acceleration generated at an earthquake isolation object as much as possible.SOLUTION: A seismic isolator comprises: a fixed part; a movable part on which a seismic isolation object is placed, and which is arranged on the fixed part; a support guide mechanism for allowing the movement of the movable part to the fixed part in a horizontal direction, and including a raceway member and a moving block which reciprocates along the raceway member; a damper unit for exerting a reaction force to the movement of the movable part to the fixed part; and an elastic restoration member for restoring the movable part to an initial position on the fixed part. The damper unit is constituted of a first damper arranged at the fixed part, and a second damper which is set smaller than the first damper in an attenuation force and a maximum movable amount, arranged between the first damper and the movable part, and connects the first damper and the movable part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a seismic isolation device that is effective against everything from small vibrations to large earthquakes. [Background technology]

[0002] Seismic isolation devices are known to protect precision equipment and buildings from earthquake motion. Such isolation devices generally include a fixed part installed on the floor or ground, a movable part on which the precision equipment, building, or other seismic isolation target is placed, and an isolator and damper provided between the fixed part and the movable part.

[0003] When vibration energy is transmitted from the fixed part to the movable part, the isolator separates the movable part from the fixed part, allowing the movable part to vibrate freely, lengthening the vibration of the movable part and reducing the response acceleration of the seismically isolated object. Furthermore, the damper absorbs the vibration energy transmitted to the movable part and quickly converges the vibration of the movable part that has been lengthened by the isolator.

[0004] In such a seismic isolation device, if the damping force of the damper is increased to accommodate seismic motion of a major earthquake, such as one exceeding a seismic intensity of 5+, the resistance force that the damper exerts against the free vibration of the movable part also increases, so that the isolator does not function sufficiently against micro-vibrations that accompany small to medium-sized earthquakes, for example, and it becomes impossible to reduce the response acceleration of the seismically isolated object against vibration. On the other hand, if the damping force of the damper is set to accommodate micro-vibrations, the displacement of the movable part will become excessive in response to large seismic motion, raising concerns about interference between the movable part and surrounding structures and making it difficult to quickly converge the vibration of the movable part.

[0005] To address these issues, Patent Document 1 discloses a seismic isolation device using elastic sliding bearings. This elastic sliding bearing combines an elastic bearing using laminated rubber with a sliding bearing, and is configured to dissipate lateral vibrations by the deformation of the laminated rubber when small vibrations act on the movable part due to a small to medium-sized earthquake, etc. Furthermore, when a large earthquake causes large vibrations that exceed the predetermined deformation amount of the laminated rubber to act on the movable part, a sliding member provided integrally with the laminated rubber slides on the fixed part, and is configured to deal with vibrations of a magnitude that are difficult for the laminated rubber to handle. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2009-281559 Summary of the Invention [Problem to be solved by the invention]

[0007] For example, in the field of precision processing such as semiconductor manufacturing, it is necessary to sufficiently reduce the response acceleration that occurs in seismically isolated objects not only in response to the large vibrations that accompany major earthquakes, but also in response to the micro-vibrations that occur in small to medium-sized earthquakes, in order to prevent adverse effects on product processing.

[0008] However, the elastic bearings and sliding bearings used in seismic isolation devices are mechanisms that combine the functions of an isolator and a damper, and it has been difficult to limit their function as a damper while still fully utilizing their function as an isolator. [Means for solving the problem]

[0009] The present invention has been made in consideration of these problems, and its purpose is to provide a vibration isolation device that can widely optimize the damping force exerted by the damper for vibrations of various magnitudes, from large seismic motions caused by mega-earthquakes to micro-vibrations caused by small to medium-sized earthquakes, and that can reduce as much as possible the response acceleration that occurs in the object to be isolated.

[0010] The seismic isolation device of the present invention comprises a fixed part, a movable part on which an object to be isolated is placed and which is arranged on the fixed part, a support guide mechanism which allows the movable part to move horizontally relative to the fixed part and which includes a track member and a movable block which moves back and forth along the track member, a damper unit which exerts a reaction force against the movement of the movable part relative to the fixed part, and an elastic restoring member which returns the movable part to its initial position on the fixed part, and the damper unit is composed of a first damper arranged relative to the fixed part, and a second damper which has a damping force and maximum movable amount set smaller than those of the first damper and is arranged between the first damper and the movable part to connect the first damper and the movable part. [Effects of the Invention]

[0011] According to the present invention, the damping force exerted by the damper can be widely optimized for vibrations of various magnitudes, ranging from large seismic motions caused by mega-earthquakes to micro-vibrations caused by small to medium-sized earthquakes, making it possible to reduce as much as possible the response acceleration occurring in the object to be isolated. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic plan view showing a first embodiment of a seismic isolation device to which the present invention is applied. [Figure 2] FIG. 10 is a perspective view showing an example of a linear guide that can be used as a support guide mechanism. [Figure 3] FIG. 10 is a cross-sectional view showing an example of a viscous damper that can be used as the first damper. [Figure 4]FIG. 10 is a perspective view showing a ball spline device that can be used as a second damper. [Figure 5] 10 is a schematic plan view showing a state in which the movable part of the seismic isolation device shown in the embodiment has started to move in the X+ direction. FIG. [Figure 6] 10 is a schematic plan view showing a state in which the movable part of the seismic isolation device shown in the embodiment has moved in the X+ direction to the maximum movable range of the second damper. FIG. [Figure 7] 7 is a schematic plan view showing a state in which the movable part has further moved in the X+ direction from the state shown in FIG. 6. FIG. [Figure 8] 8 is a schematic plan view showing a state in which the movable part starts to move in the X-direction from the state shown in FIG. 7. FIG. [Figure 9] 8 is a schematic plan view showing a state in which the movable part has moved further in the X-direction from the state shown in FIG. 7. FIG. [Figure 10] FIG. 10 is a perspective view showing a second embodiment of a seismic isolation device to which the present invention is applied. [Figure 11] 10 is a perspective view showing a state in which a movable part and one of the second dampers have been removed from the seismic isolation device according to the second embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] The seismic isolation device of the present invention will be described in detail below with reference to the accompanying drawings.

[0014] Figure 1 is a schematic plan view showing a first embodiment of a seismic isolation device 1 to which the present invention is applied. The seismic isolation device 1 of this first embodiment includes a fixed part 2 that is installed on a floor surface, the ground, etc., a movable part 3 on which an object to be seismically isolated, such as a precision instrument or a building, is placed, a support guide mechanism 4 that serves as an isolator that guides the movement of the movable part 3 in the horizontal direction (the direction of the arrow X in Figure 1) relative to the fixed part 2, a damper unit 5 that applies a reaction force to the movement of the movable part 3 in the X direction, and an elastic restoring member 6 that returns the movable part 3 to its initial position on the fixed part 2.

[0015] The fixed part 2 is, for example, a fixed table installed on the floor of a building or loading platform if the object to be isolated is a precision instrument or a work of art, and is a building foundation installed on the ground if the object to be isolated is a building.

[0016] Furthermore, if the seismic isolation object is a precision instrument or a work of art, the movable part 3 is, for example, a movable table supported on the fixed table via the support and guide mechanism, and if the seismic isolation object is a building, it is a sturdy movable frame supported on the building foundation via the support and guide mechanism.

[0017] 2 can be used as the support guide mechanism 4. This linear guide 40 is composed of a track member 41 that is laid on the fixed part 2 along the X direction and has a rolling surface 41a of balls or rollers formed along the longitudinal direction, and a movable block 42 that has an infinitely circulating row of rolling elements inside and is capable of freely reciprocating along the track member 41. The movable part 3 is fixed to the movable block 42, and when the movable block 42 reciprocates along the track member 41, the movable part 3 also moves in the X direction on the fixed part 2 together with the movable block 42.

[0018] The support guide mechanism 4 is not limited to the linear guide 40 shown in FIG. 2, as long as it can ensure free linear reciprocating motion of the movable part 3 relative to the fixed part 2.

[0019] On the other hand, the damper unit 5 is composed of a combination of a first damper 50 and a second damper 51. The first damper 50 is provided to correspond to the range of movement of the movable part 3 on the fixed part 2, i.e., the range of movement of the movable part by the support guide mechanism, and is adapted to withstand seismic motion such as a major earthquake, which has a large amplitude and large vibration energy. On the other hand, the second damper 51 is provided between the first damper 50 and the movable part 3, connecting the first damper 50 and the movable part 3, and is adapted to withstand micro-vibrations, such as small to medium-sized earthquakes, traffic vibrations, and wind-induced shaking of buildings, which have a small amplitude and small vibration energy.

[0020] As the first damper 50, for example, a viscous damper 70 as shown in Fig. 3 can be used. The viscous damper 70 includes a threaded shaft 71 that is provided on the fixed part with its axial direction aligned with the X direction and has a helical thread groove formed on its outer peripheral surface, a damper body 72 that is formed in a cylindrical shape through which the threaded shaft 71 passes and that reciprocates along the threaded shaft 71, a rotor 73 that is rotatably held inside the damper body 72, and a nut member 74 that is threadedly engaged with the threaded shaft 71 via a number of balls that roll in the thread grooves of the threaded shaft 71 and is fixed to the axial end of the rotor 73. A viscous fluid is filled between the inner peripheral surface of the damper body 72 and the outer peripheral surface of the rotor 73.

[0021] The screw shaft 71 and the nut member 74 constitute a so-called ball screw device, and when the damper body 72 moves on the fixed part 2 in the axial direction of the screw shaft 71, the nut member 74 rotates around the screw shaft 71, and the rotation is transmitted to the rotor 73. In other words, when the damper body 72 makes a linear reciprocating motion along the screw shaft 71, the rotor makes a rotational reciprocating motion inside the damper body, and a shear resistance force corresponding to the rotational speed of the rotor acts on the rotor from the viscous fluid.

[0022] The shear resistance force acting on the rotor 73 from the viscous fluid becomes a reaction force against the rotary reciprocating motion of the rotor 73, and is converted by the ball screw device to become a reaction force against the linear reciprocating motion in the X direction of the damper body 72. This makes it possible to attenuate the energy that moves the damper body 72 in the X direction.

[0023] 3 is merely an example of a damper that can be used as the first damper 50, and is not limited to this. In other words, various types of dampers can be selected as the first damper 50 depending on the required range of motion and the magnitude of the damping force.

[0024] On the other hand, the second damper 51 is composed of a guide shaft 81 whose axial direction is aligned with the X direction relative to the movable part 3, and a sliding member 82 that is connected to the damper body 72 of the first damper 50 and moves along the guide shaft 81.

[0025] In this first embodiment, a ball spline device 80 shown in FIG. 4 is used as the second damper. A rolling groove 81a for rolling elements is provided on the outer peripheral surface of the guide shaft 81 along the axial direction, and the sliding member 82 is attached to the guide shaft 81 via an infinitely circulating row of rolling elements. The rolling elements roll on the rolling groove 81a of the guide shaft 81, allowing the sliding member 82 to reciprocate along the guide shaft 81 with extremely small movement resistance. Meanwhile, the movement resistance of the sliding member 82 relative to the guide shaft 81 can be increased or decreased as desired by adjusting the magnitude of the preload applied to the rolling elements interposed between the guide shaft 81 and the sliding member 82. In this sense, the ball spline device 80 functions as a damper with extremely small damping force.

[0026] 4 is merely an example of a device that can be used as the second damper 51, and is not limited to this. Various types of dampers can be selected depending on the range of motion required for the second damper 51 and the magnitude of the required damping force.

[0027] Both ends of the guide shaft 81 are fixed to the movable part 3 by a pair of support members, and the sliding member 82 coupled to the first damper 50 is movable along the guide shaft 81 only between the pair of support members. In this way, the damper unit 5 has a structure in which the first damper 50 is connected to the movable part 3 via the second damper 51, in other words, a structure in which the first damper 50 and the second damper 51 are provided in series between the fixed part 2 and the movable part 3. The damping force exerted by the second damper 51, i.e., the magnitude of the reaction force exerted against the linear reciprocating motion of the movable part 3, is set smaller than the damping force exerted by the first damper 50.

[0028] Furthermore, the first damper 50 is configured to exert a damping force over substantially the entire range of movement of the movable part 3, whereas the second damper 51 is configured to exert a damping force only within a range narrower than that of the first damper 50. In other words, the maximum movable amount of the second damper 51 is set smaller than that of the first damper 50.

[0029] Therefore, when the movable part 3 moves in the X direction, the second damper 51 in the damper unit 5 operates before the first damper 50, and when the movement amount of the movable part 3 exceeds the movable range of the second damper 51, the first damper 50 operates.

[0030] The elastic restoring member 6 includes a first restoring member 61 provided between the damper body 72 of the first damper 50 and the fixed part 2, and a second restoring member 62 provided between the movable part 3 and the fixed part 2. The first restoring member 61 serves to return the first damper 50 to its initial position before operation after the vibration transmitted to the movable part 3 has subsided. In addition, the second restoring member 62 serves to return the movable part 3 to its initial position before operation after the vibration transmitted to the movable part 3 has subsided.

[0031] The seismic isolation device 1 of the first embodiment configured as above operates as follows.

[0032] For example, when an earthquake occurs and vibration acts on the fixed part 2, the movable part 3 is separated from the fixed part 2 by the operation of the support guide mechanism 4, and a relative linear reciprocating motion in the X direction occurs between the fixed part 2 and the movable part 3. As shown in Fig. 5, when the movable part 3 first starts to move in the X+ direction relative to the fixed part 2, only the second damper 51, which has a damping force smaller than that of the first damper 50, operates, and the first damper 50 does not operate. That is, in the first damper 50, the damper body 72 does not move relative to the screw shaft 71, and in the second damper 51, the sliding member 82 moves relative to the guide shaft 81.

[0033] Therefore, if the amplitude of the vibration generated in the movable part 3 is within the movable range of the second damper 51, in this seismic isolation device 1, only the second damper 51 operates without operating the first damper 50, and the second damper 51 absorbs the vibration energy transmitted from the fixed part 2 to the movable part 3, thereby quickly converging the vibration of the movable part 3.

[0034] Furthermore, because the damping force of the second damper 51 is set smaller than that of the first damper 50, it is possible to operate the support guide mechanism 4 as an isolator sufficiently even against micro-vibrations such as small to medium-sized earthquakes, wind-induced shaking of the building, and traffic vibrations, thereby isolating the movable part 3 from vibrations of the fixed part 2. For this reason, this seismic isolation device 1 can sufficiently reduce the response acceleration occurring in the seismic isolation object mounted on the movable part 3 even against micro-vibrations, and is effective as a countermeasure against vibrations in precision processing equipment such as semiconductor manufacturing equipment.

[0035] On the other hand, when the vibration generated in the movable part 3 causes the movable part 3 to move in the X+ direction beyond the movable range of the second damper 51, the sliding member 82 of the second damper 51 hits the support member that supports the guide shaft 81 as shown in Fig. 6, and as the movable part 3 moves further in the X+ direction, the first damper 50 starts to operate from this point. That is, as shown in Fig. 7, the damper body 72 of the first damper 50 coupled with the sliding member 82 of the second damper 51 moves relative to the screw shaft 71, and the first damper 50 absorbs the vibration energy transmitted from the fixed part 2 to the movable part 3, thereby converging the vibration of the movable part 3.

[0036] After that, when the movement direction of the movable part 3 is reversed from the X+ direction to the X- direction, only the second damper 51, which has a smaller damping force than the first damper 50, operates against the movement of the movable part 3 in the X- direction, as shown in Fig. 8. At this time, the first damper 50 does not operate, and the damper body 72 of the first damper 50 remains in the position on the screw shaft 71 when the movement direction of the movable part 3 is reversed.

[0037] Then, when the movable part 3 moves further in the X-direction and the sliding member 82 of the second damper 51 hits the support member that supports the guide shaft 81, the first damper 50 starts to operate. That is, as shown in Fig. 9, with the sliding member of the second damper 51 hitting the support member for the guide shaft, the damper body 72 of the first damper 50 moves in the X-direction relative to the screw shaft 71, and the first damper 50 absorbs the vibration energy transmitted from the fixed part 2 to the movable part 3, thereby converging the vibration of the movable part 3.

[0038] As described above, in the seismic isolation device 1 of the first embodiment, when a large earthquake causes seismic motion with a large amount of movement to act on the fixed part 2, causing the movable part 3 to move beyond the movable range of the second damper 51 relative to the fixed part 2, the first damper, which exerts a damping force greater than that of the second damper 51, operates. As a result, even when the enormous seismic energy of a large earthquake is transmitted to the movable part, the large damping force exerted by the first damper can suppress the maximum displacement of the movable part, and the vibration of the movable part 3 can be quickly converged.

[0039] Next, a second embodiment of a seismic isolation device to which the present invention is applied will be described.

[0040] Figure 10 shows a seismic isolation device of the second embodiment. Similar to the first embodiment, the seismic isolation device 1A of this second embodiment supports a movable part 3 on a fixed part 2 via a support guide mechanism 4, and the movable part 3 is freely movable on the fixed part 2 in the X direction. The linear guide 40 shown in Figure 2 can be used as the support guide mechanism 4 of this second embodiment. In the example shown in Figure 10, a track member 41 is laid on the fixed part 2 along the X direction, and a moving block 42 that slides on the track rail 41 is fixed to the movable part.

[0041] A damper unit 5 is provided between the fixed part 2 and the movable part 3. The damper unit 5 is composed of a combination of a first damper 50 and a pair of second dampers 51. The first damper 50 is provided corresponding to the movable range of the movable part 3 on the fixed part 2, i.e., the range of movement of the movable part by the support guide mechanism 4, while the second damper 51 is provided between the first damper 50 and the movable part 3 and connects the first damper 50 and the movable part 3.

[0042] 11 is a perspective view showing a state in which one of the movable part 3 and the second damper 51 is removed to expose the first damper 50. The first damper 50 includes a rack 52 fixed to the fixed part 2 along the X direction, a pinion gear 53 that rotates in mesh with the rack 52, and a rotary damper 54 that is rotated by the pinion gear 53 and is fixed to the second damper 51. The rack 52 is installed on the fixed part 2 in a position corresponding to the range of motion of the moving block 42 of the support and guide mechanism 4. A viscous fluid is sealed in the rotary damper 54, and when rotational motion is input from the pinion gear 53, the rotary damper 54 is configured to exert a damping force on the rotational motion.

[0043] 11 , the second damper includes a sliding member 55 fixed to the movable part 3, a guide shaft 56 to which the sliding member 55 is assembled via a number of rolling elements and which is provided along the X direction, an intermediate plate 57 on which the guide shaft 56 is laid, and a pair of locking members 58 provided on the intermediate plate 57 corresponding to both longitudinal ends of the guide shaft 56. The intermediate plate 57 is suspended from the movable part 3 via the sliding member 55 and the guide shaft 56, and the guide shaft 56 moves in the X direction relative to the movable part 3 as the guide shaft 56 moves in the X direction relative to the sliding member 55. However, since the guide shaft 56 is set to be shorter than the length of the track rail 41 of the support and guide mechanism 4, the moving range of the movable part 3 relative to the intermediate plate 57 is set to be shorter than the moving range of the movable part 3 relative to the fixed part 2.

[0044] The combination of the sliding member 55 and the guide shaft 56 functions as a damper with an extremely small damping force, similar to the ball spline device of the first embodiment. That is, by arbitrarily adjusting the magnitude of the preload applied to the rolling elements interposed between the sliding member 55 and the guide shaft 56, it is possible to arbitrarily increase or decrease the movement resistance of the sliding member 55 with respect to the guide shaft 56.

[0045] The rotary damper 54 is fixed to the back side of the intermediate plate 57, i.e., the surface opposite to the surface on which the guide shaft 56 is laid. Therefore, when the intermediate plate 57 moves relative to the fixed part 2, the pinion gear 53 meshing with the rack 52 rotates, causing the rotary damper 54 to exert a damping force, which acts on the movement of the intermediate plate 57 in the X direction.

[0046] 10 and 11, an elastic restoring member formed of, for example, a coil spring is provided between the movable part 3 and the fixed part 2, and applies a biasing force in a direction returning the movable part 3, which has vibrated in the X direction on the fixed part 2, to the center position of the amplitude of the vibration. A similar elastic restoring member is also provided between the fixed part 2 and the intermediate plate 57, and applies a biasing force in a direction returning the intermediate plate 57 to its initial position on the fixed part.

[0047] The seismic isolation device of the second embodiment configured as above operates as follows.

[0048] For example, when an earthquake occurs and vibration acts on the fixed part 2, the movable part 3 supported by the support guide mechanism 4 serving as an isolator moves in the X direction relative to the fixed part 2, causing a reciprocating motion on the fixed part 2. If the amplitude of the reciprocating motion of the movable part 3 at this time is within the movable range of the second damper 51, i.e., within the movable range of the sliding member 55 relative to the guide shaft 56, only the weak damping force of the second damper 51 acts on the movable part 3. At this time, the intermediate plate 57 is in a substantially stationary state on the fixed part 2.

[0049] As a result, similarly to the first embodiment described above, the second damper 51 absorbs vibration energy transmitted from the fixed part 2 to the movable part 3 in response to micro-vibrations such as small to medium-sized earthquakes, wind-induced vibration of the building, and traffic vibration, thereby quickly converging the vibration of the movable part 3. Furthermore, since the damping force of the second damper 51 is smaller than that of the first damper 50, the support guide mechanism 4 can be operated sufficiently as an isolator, and the response acceleration occurring in the seismic isolation object mounted on the movable part 3 can be sufficiently reduced.

[0050] On the other hand, when the amplitude of the reciprocating motion of the movable part 3 exceeds the movable range of the second damper 51, the movable part 3 hits a locking member 58 provided on the intermediate plate 57, and the intermediate plate moves in the X direction on the fixed part 2 together with the movable part 3, being dragged by the movable part 3.

[0051] As a result, in the first damper 50, the rotary damper 54 moves in the X direction relative to the fixed part 2, causing the pinion gear meshing with the rack to rotate, and the damping force of the rotary damper 54 acts on the movement of the intermediate plate 57 in the X direction. Since the intermediate plate 57 is dragged by the movable part 3 and moves in the X direction, the damping force exerted by the rotary damper 54 acts on the movement of the movable part 3 in the X direction.

[0052] In this way, even in the seismic isolation device 1A of the second embodiment shown in Figure 10, if a large earthquake causes large-amplitude seismic motion to act on the fixed part 2 and the movable part 3 moves beyond the movable range of the second damper 51 relative to the fixed part 2, the first damper 50, which exerts a larger damping force than the second damper 51, will operate, and the large damping force exerted by the first damper 50 will make it possible to suppress the maximum displacement of the movable part and to quickly converge the vibration of the movable part 3.

[0053] As explained above, according to the seismic isolation devices of the first and second embodiments, by connecting two types of dampers with different damping forces and maximum movable ranges in series between the fixed part 2 and the movable part 3, it is possible to sufficiently reduce the response acceleration occurring in the seismically isolated object mounted on the movable part in response to minute vibrations caused by small to medium-sized earthquakes, wind swaying of buildings, traffic vibrations, etc., and it is also effective against large amounts of movement and large energy vibrations associated with major earthquakes, making it possible to widely optimize the damping force exerted by the dampers in response to various types of vibrations and to reduce as much as possible the response acceleration occurring in the seismically isolated object.

[0054] Furthermore, by setting the damping force exerted by the second damper 51 to an arbitrary magnitude, it becomes possible to optimize the seismic isolation device for various uses.

[0055] In the embodiment of the present invention shown in the figures, an example has been given in which the movable part vibrates only in the X direction, but it is also possible to create a seismic isolation device that operates within a horizontal two-dimensional plane by stacking a seismic isolation device whose movable part vibrates in the X direction with a seismic isolation device whose movable part vibrates in the Y direction perpendicular to the X direction. [Explanation of symbols]

[0056] 1... Seismic isolation device, 2... Fixed part, 3... Movable part, 4... Support guide mechanism, 5... Damper unit, 6... Elastic restoring member, 50... First damper, 51... Second damper

Claims

1. A fixed portion; a movable part on which an object to be isolated is placed and which is disposed on the fixed part; a support and guide mechanism that allows the movable part to move horizontally relative to the fixed part and includes a track member and a moving block that reciprocates along the track member; a damper unit that exerts a reaction force against the movement of the movable part relative to the fixed part; an elastic restoring member that returns the movable part to an initial position on the fixed part, The damper unit is a first damper disposed relative to the fixed portion; A seismic isolation device characterized by being composed of a second damper whose damping force and maximum movable amount are set smaller than those of the first damper, and which is arranged between the first damper and the movable part to connect the first damper and the movable part.

2. 2. The seismic isolation device according to claim 1, wherein the first damper operates only when the amount of movement of the movable part exceeds the maximum amount of movement of the second damper.

3. 2. The seismic isolation device according to claim 1, wherein the second damper includes a guide shaft arranged parallel to a track member of the support guide mechanism, and a sliding member that moves along the guide shaft.

4. 4. The seismic isolation device according to claim 3, wherein the first damper operates when the movable portion moves beyond the movable range of the sliding member relative to the guide shaft of the second damper.

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