JPH1137211A - Base isolation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high flexible and inexpensive base isolation device; having high freedom in the movement of an intermediate mount, eliminating the strike of an upper structure to the intermediate mount even if the upper structure is deflected by an upper loaded load, and moreover commonly usable in all installing places regardless of width of installing areas; in the base isolation device having plural base isolation units wherein turnable bodies are arranged between a lower structure and the intermediate mount, and the intermediate mount and the upper structure respectively. SOLUTION: Four base isolation units are installed between the four corners of an upper structure and a lower structure. Each base isolation unit is equipped with an intermediate mount 40, an upper roller 50 rollable in a first direction on the upper side of the intermediate mount 40, and a lower roller 60 rollable in a second direction orthogonal to the first direction on the lower side of the intermediate mount 40. The intermediate mounts 40 of the four base isolation units are separated with each other to be made displaceable independently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention blocks or reduces transmission of vibration of a lower structure caused by an earthquake or the like to buildings, nuclear machinery, measuring instruments, computers, display cases, etc. The present invention relates to a seismic isolation device that can restore an object to its original position before vibration.

[0002]

2. Description of the Related Art Conventionally, as a seismic isolation device, there is one in which four seismic isolation units are arranged between a lower structure fixed to the ground and an upper structure such as a building or a display case. The seismic isolation unit includes an upper structure, a lower structure, an intermediate table between the upper structure and the lower structure, and further includes a first direction between the upper structure and the intermediate table. And a second roller that rolls in a second direction orthogonal to the first direction is disposed between the lower structure and the intermediate table. A concave curved surface is formed on the upper surface of the intermediate table so that the first rollers rolling in the first direction roll toward the stable point by the action of gravity. In addition, a concave curved surface is formed on the upper surface of the lower base so that the second rollers rolling in the second direction roll toward a stable point by the action of gravity.
Further, the intermediate platform of the four seismic isolation units is formed by a common intermediate platform.

As described above, the rolling of the first and second rollers which roll in the first and second directions orthogonal to each other and return to a stable point causes the vibration of the lower structure to move to the upper structure. If the transmission is interrupted or reduced and the earthquake subsides, the first
By returning the rollers and the second roller to the stable point, the upper structure is returned to the rest position.

[0004]

However, in the above-mentioned conventional example, it has been found that the following problem occurs because the intermediate base of the four seismic isolation units is formed of a single common plate. .

(1) Since the intermediate bases of a plurality of seismic isolation units are not independent of each other, in each seismic isolation unit, the intermediate base cannot move freely in accordance with the rolling of the corresponding roller. That is, the degree of freedom of movement of the intermediate platform is low.

(2) When the upper structure is deflected by an overburden load, the upper structure hits the central portion of the intermediate table.

(3) The size of the intermediate stand depends on the installation area of the seismic isolation device, that is, the width of the bottom surface of the upper structure. . Therefore, the intermediate platform used for one installation location cannot be used for another installation location, and lacks flexibility. In addition, if the installation location of the seismic isolation device is vast, it is necessary to increase the dimensions of the intermediate stand, which requires a large amount of material, resulting in high cost.

Therefore, an object of the present invention is a seismic isolation device having a plurality of seismic isolation units each having a rolling element disposed between a lower structure and an intermediate table and between an intermediate table and an upper structure. High flexibility of movement of the intermediate table, so that the upper structure does not hit the intermediate table even if the upper structure flexes due to the overload, and can be used in all installation locations regardless of the installation area. An object of the present invention is to provide a highly inexpensive seismic isolation device.

[0009]

According to a first aspect of the present invention, there is provided a seismic isolation device which is disposed between an intermediate base, the intermediate base and an upper structure, and is rotated in a first direction. A first rolling element movable between the intermediate platform and the lower structure, and a second rolling element rotatable in a second direction intersecting the first direction. A stable point formed on at least one of the lower surface of the upper structure and the upper surface of the intermediate platform, and having the stable point on both sides of the stable point. A first track surface that relatively rolls by the action of gravity, and is formed in at least one of the upper surface of the lower structure or the lower surface of the intermediate platform in the second direction, and has a stable point; On both sides of this stable point, the second rolling element is moved toward the stable point by the action of gravity. At least three seismic isolation units having a second raceway surface for rolling between the lower structure and the upper structure, spaced apart from each other; Are characterized in that they are separated from each other and can be displaced independently.

As described above, since the intermediate bases of the plurality of seismic isolation units are separated from each other, free movement of each intermediate base is ensured. This free movement of the intermediate table occurs not only at the time of vibration, but also when the upper structure is bent by the overload, and the bent upper structure does not hit the central portion of the intermediate table. .

Further, since the intermediate bases of the plurality of seismic isolation units are separated from each other, the dimensions of the intermediate bases are independent of the area of the place where the seismic isolation device is installed, ie, the area of the bottom of the upper structure. That is, the dimensions of the intermediate table can be arbitrarily reduced. Therefore, compared with a case where a plurality of intermediate bases are connected, the intermediate base requires much less material, and the cost is reduced.

Further, the plurality of seismic isolation units are completely separated from each other because the intermediate stand is separated from each other. Therefore, the seismic isolation unit can be easily handled, and the number of seismic isolation units to be used can be freely increased or decreased, and the seismic isolation unit can be freely installed at a desired location. In other words, the degree of freedom in arranging the seismic isolation units is high. If the number of seismic isolation units is at least three, the upper structure can be supported by the lower structure. However, the number of seismic isolation units to be used is determined according to the area and weight of the upper structure to be supported. do it.

According to a second aspect of the present invention, there is provided the seismic isolation device according to the first aspect, wherein a length of the first raceway surface along a first direction and a length of the second raceway surface along the first direction. The length along the two directions is characterized by being greater than the horizontal amplitude of the earthquake.

As described above, the length of the first track surface along the first direction and the length of the second track surface along the second direction are larger than the horizontal amplitude of the earthquake. Since the first rolling element and the second rolling element at the time of the earthquake,
Each does not exceed the first orbital surface and the second orbital surface. Therefore, the first and second rolling elements do not derail from the first and second raceway surfaces during an earthquake, respectively, and return to the stable point after the earthquake has stopped.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 is a cross-sectional view of a building 30 having a seismic isolation floor on which a seismic isolation device according to an embodiment of the present invention is installed. FIGS. 2 and 3 are II-II of FIG.
FIG. 4 is a sectional view taken along line IV-IV of FIG. 1 in a state where the floor is bent.

In FIG. 1, 31 is a wall, and 20 is a movable floor plate as an upper structure. The floor plate 20 is shown in FIG.
As shown in FIGS. 1 to 4, the lower side of the fixed floor 33 formed along the inside of the wall 31 is provided so as to be movable with its peripheral portion superimposed on the fixed floor 33. A floor slab 10 is provided below the floor plate 20 as a lower structure.
Between 0 and four seismic isolation units U each independent of each other
Are installed via an upper base 21 fixed to the lower surface of the floor plate 20 as an upper structure, and a lower base 11 fixed to the floor slab 10 as a lower structure.

Next, the structure of each seismic isolation unit U is shown in FIGS.
This will be described in detail with reference to FIG. As shown in FIGS. 5 and 6, the seismic isolation unit U includes an intermediate base 40 which is a rectangular plate,
A first provided between the intermediate table 40 and the upper table 21
An upper roller 50 as a rolling element, and a second roller provided at right angles to the upper roller 50 between the intermediate table 40 and the lower table 11.
A lower roller 60 as a rolling element is provided.

The upper roller 50 and the lower roller 60 are shown in FIG.
As shown in FIG. 6 and FIG. 6, they have the same shape and the same cylindrical shape, each having two grooves 50c, 50c in the circumferential direction.
And 60c, 60c.

A flat raceway surface 22 on which the upper rollers 50 roll is formed on the lower surface of the upper base 21. further,
On this track surface 22, two linear protrusions 21a, 21
a is formed in the first direction in which the upper roller 50 rolls.

On the upper surface of the intermediate table 40, there is formed a concave first raceway surface 43 having a constant curvature and rising gradually from the center stable point 41 toward both sides. On the first raceway surface 43, two protrusions 40a, 40a are formed at positions facing the protrusions 21a, 21a. At both ends of the first concave raceway surface 43, stoppers 44 for preventing the upper roller 50 from falling down are provided.

On the lower surface of the intermediate table 40, a flat raceway surface 42 on which the lower roller 60 rolls is formed.
Further, on the raceway surface 42, two linear projections 40b, 40b are formed in a direction in which the lower roller 60 rolls, that is, in a second direction perpendicular to the first direction. .

On the upper surface of the lower base 11, a concave second raceway surface 13 having a constant curvature and rising gradually from the center stable point 12 toward both sides is formed. This second
Two projections 11a, 11a are formed on the raceway surface 13 at positions facing the projections 40b, 40b. Further, lower rollers 6 are provided at both ends of the concave second raceway surface 13.
Stoppers 14, 14 for preventing the 0 from falling are provided.

The protrusions 21a, 21a of the upper base 21 and the protrusions 40a, 40a of the intermediate base 40 are formed by grooves 50c, 5 of the upper roller 50.
0c, and the protrusions 40b, 40b of the intermediate base 40 and the protrusions 11a, 11a of the lower base 11
60c.

In this manner, the upper roller 50 and the lower roller 60 are mounted on the intermediate table 40 and the lower table 11 in a state of being fitted into the grooves 50c, 50c and the grooves 60c, 60c, respectively.

When there is no earthquake, the upper rollers 50 as the first rolling elements are connected to the stable points 4 on the first raceway surface 43.
1 is stationary. Further, the lower roller 60 as the second rolling element is stationary at the stable point 12 of the second raceway surface 13.
In this state, the weight of the upper structure is determined by the weight of the floor plate 20, the upper base 21, the upper rollers 50, the intermediate base 40, the lower rollers 60, the lower base 11, and the floor slab 10 of the upper structure. It is transmitted vertically downward in order, and can support a large vertical load.

On the other hand, during an earthquake, the ground shakes in the horizontal direction due to the earthquake, and the floor slab 10 and the lower base 11, which are a part of the lower structure, move in the horizontal direction together with the ground. Then, the lower roller 60 is in contact with the second track surface 13 of the lower base 11.
And rolling along the raceway surface 43 of the intermediate table 40,
The upper rollers 50 roll along the first raceway surface 43 of the intermediate platform 40 and the raceway surface 22 of the upper platform 21. Thereby, the horizontal vibration of the ground transmitted through the lower structure is not transmitted to the upper structure. That is, the lower roller 11 rolls with respect to the second raceway surface 13 and the upper roller 50 rolls with respect to the first raceway surface 43, thereby lowering the lower base 11.
The upper base 21 can move relative to any horizontal direction. Therefore, the seismic isolation unit including the upper rollers 50, the intermediate base 40, and the lower rollers 60 substantially completely absorbs the horizontal vibration of the ground, and hardly transmits the vibration to the upper structure.

The upper roller 50 rolls on the first raceway surface 43 and the raceway surface 22, and the lower roller 60 rolls on the second raceway surface 13 and the raceway surface 42. Because the slide is relatively smooth, you can approach the absolute seismic isolation. Therefore, even when applied to not only large-scale structures but also medium- and small-scale structures, it is possible to surely prevent the shaking of the earthquake from being transmitted to the buildings.

After the earthquake has subsided, the upper rollers 50 return to the stable point 41 while reciprocating on the rising surfaces on both sides of the stable point 41 on the first track surface 43. At the same time, the lower roller 60 returns to the stable point 12 while reciprocating on the rising surfaces on both sides of the stable point 12 of the second raceway surface 13. Therefore, the upper base 21 returns to the position at the time of rest with respect to the lower base 11, and the structure can be reliably returned to the position at the time of rest with respect to the ground.

Further, in this seismic isolation device, since the first raceway surface 43 and the second raceway surface 13 extend in a direction orthogonal to each other, the ground vibration is generated between the first direction and the second direction. , The relative sliding of the upper table 21 and the lower table 11 can be smoothly performed in all directions in the horizontal direction.

Further, the seismic isolation device is provided with the first track surface 4.
The third and second raceway surfaces 13 are curved surfaces having a constant curvature in the rolling direction of the upper roller 50 and the lower roller 60. Therefore, the magnitude of the restoring force can be set to a desired value by setting the curvature of the curved surface.

The seismic isolation unit is provided with a first track surface 4.
3 and a projection 4 extending on the raceway surface 22 in the first direction, respectively.
0a, 21a, and is fitted in the groove 50c of the upper roller 50. Further, on the second raceway surface 13 and the raceway surface 42, there are projections 40 b and 11 a extending in the second direction, respectively, and are fitted with the grooves 60 c of the lower roller 60. Therefore, the upper rollers 50 are not displaced from the first raceway surface 43 and the raceway surface 22 along the groove 50c.
The guide is guided along the groove 60c so as not to deviate from the second raceway surface 13 and the raceway surface 42.

As shown in FIG. 7, the rolling distance of the upper roller 50 on the first raceway surface 43 and the second raceway surface 1
The maximum value of the distance over which the lower roller 60 on 3 rolls is set to the assumed maximum horizontal amplitude L during an earthquake. in this way,
The maximum value of the distance that the upper roller 50 rolls and the lower roller 60
Since the maximum value of the rolling distance of is set to the assumed maximum horizontal amplitude L at the time of the earthquake, the upper roller 50 and the lower roller 60 are connected to the first track surface 43 of the intermediate table 40 and the second track of the lower table 11.
There is no rolling beyond the raceway surface 13.

Further, stoppers 44 and 14 are provided at the ends of the first raceway surface 43 and the end of the second raceway surface 13, respectively, so that the ground exceeds the assumed maximum horizontal amplitude L. Even if the upper roller 50 and the lower roller 60 try to roll beyond the first raceway surface 43 and the second raceway surface 13, respectively, the upper roller 50 or the lower roller 60 is moved by these stoppers 44, 14. , Respectively, is prevented from deviating from the first raceway surface 43 or the second raceway surface 13, respectively.

The seismic isolation device having the above configuration stably supports the load from the floor plate 20 in a normal state where no vibration occurs. Here, it is assumed that a heavy computer, a measuring machine, or the like is installed on the floor plate 20, and a load LD is applied on the floor plate 20 as shown in FIGS. At this time, the intermediate platform 4 of the four seismic isolation units U
0 are separated from each other, and the intermediate table 40 does not exist at the center of the floor panel 20 or at an intermediate portion of each side, so that the floor panel 20 bent downward does not hit the intermediate table 40. Therefore,
It does not occur that the rolling of the upper roller 50 or the lower roller 60 is hindered by the contact of the intermediate table 40 with the floor plate 20. Moreover, as shown in FIG.
Tilts with the lower roller 60 as a fulcrum. At this time, since the intermediate table 40 is separated from the intermediate table 40 of another seismic isolation unit, the intermediate table 40 can be freely tilted without being restricted by the other intermediate table 40.

As described above, since the intermediate bases of the plurality of seismic isolation units are separated from each other, free movement of each intermediate base is ensured. This free movement of the intermediate table occurs not only at the time of vibration, but also when the upper structure bends due to the overload, and the upper structure bent like a single common intermediate table has an intermediate structure. The phenomenon of hitting the center of the table does not occur with the above seismic isolation device.

Further, since the intermediate bases of the plurality of seismic isolation units are separated from each other, the dimensions of the intermediate bases are independent of the area of the installation location of the seismic isolation device, that is, the area of the bottom of the upper structure. That is, the dimensions of the intermediate table can be arbitrarily reduced. Therefore, compared with a case where a plurality of intermediate bases are connected, the intermediate base requires much less material, and the cost is reduced.

Further, the plurality of seismic isolation units are completely separated from each other because the intermediate stand is separated from each other. Therefore, the seismic isolation unit can be easily handled, and the number of seismic isolation units to be used can be freely increased or decreased, and the seismic isolation unit can be freely installed at a desired location. In other words, the degree of freedom in arranging the seismic isolation units is high. If the number of seismic isolation units is at least three, the upper structure can be supported by the lower structure. However, the number of seismic isolation units to be used is determined according to the area or weight of the upper structure to be supported. do it.

In this embodiment, not only the plurality of seismic isolation units U but also the plurality of lower bases 11 and upper bases 21 are independent of each other, and therefore, each is formed in a small size, so that it is easy to carry. , When installing the seismic isolation device,
These members can be easily handled and work can be performed easily.

In the seismic isolation device having the above structure, for example, the lower structure is fixed to the ground, and the upper base 21 is fixed to the upper structure. Then, only a plurality of seismic isolation units having the above configuration are installed depending on the scale of the structure.

In the above embodiment, four seismic isolation units are used, but three or five or more may be used depending on the bottom area or weight of the upper structure. In this case, since the seismic isolation device has a configuration in which the intermediate stands are completely independent of each other, the number of used seismic isolation units can be increased or decreased without changing the dimensions of the intermediate stand, and the installation position can be set freely.

In the above embodiment, the upper base fixed to the lower surface of the floor plate is treated as an upper structure, and the lower base fixed to the floor slab is treated as a lower structure. Each part may be regarded as a part of the unit U and fixed to the lower surface of the floor plate and the floor slab.

In the above-described embodiment, FIGS.
As shown in the figure, cylindrical rollers were used as rolling elements.
As shown in FIGS. 8 and 9, wheels connected by an axle may be used. In FIGS. 8 and 9, the track surfaces are shown in FIGS.
Instead of the groove shown in FIG. 7, a rail track is drawn in the direction in which the rolling element rolls. This rail track stabilizes the directionality of the rolling elements and prevents the rolling elements from causing lateral displacement and deviating from the track surface.

In the above embodiment, the track surface is shown in FIG.
Although it is a concave shape having a constant curvature like an arc as shown in FIG. 0, it may be a trochoid shape as shown in FIG. 11 or an elliptical shape as shown in FIG. In the case of FIG. 10, as shown in FIG.
As the roller moves in the y direction, it is displaced in an arc in the z direction. The restoring force at this time becomes a straight line and is proportional to the movement of the roller in the y direction. In the case of FIG. 11, FIG.
As shown in (b), the roller is displaced in a z-direction by drawing a trochoid curve as it moves in the y-direction. The restoring force at this time becomes a sinusoidal curve and becomes non-linear.
It increases or decreases with movement in the direction, and the restoring force disappears at the end. In the case of FIG. 12, as shown in FIG.
As the roller moves in the y direction, it is displaced in an elliptic curve in the z direction. The restoring force at this time becomes an odd-order function-like curve, becomes nonlinear, and increases with the movement of the roller in the y direction. As shown in FIGS. 11C and 12C, when the restoring force is nonlinear, the floor slab 10 and the floor plate 2
Shaking with zero is less likely to resonate, exhibiting an even better seismic isolation effect.

Further, in the above embodiment, the concave track surface is formed on the upper surface of the upper table and the upper surface of the intermediate table, but may be formed on the lower surface of the upper table and the lower surface of the intermediate table. Alternatively, it may be formed on the lower surface of the upper table and the upper surface of the lower table, or may be formed on the upper and lower surfaces of the intermediate table. Further, concave track surfaces may be formed on the track surfaces, that is, on the lower surface of the upper table, the upper surface of the lower table, and the upper and lower surfaces of the intermediate table.

In the above embodiment, the first direction and the second direction are at a right angle, but they may intersect at an angle other than a right angle.

[0046]

As is apparent from the above description, the seismic isolation device of claim 1 includes at least three seismic isolation units,
Each of the seismic isolation units is disposed between the intermediate platform and the upper structure, and is capable of rolling in a first direction.
A rolling element, and a second rolling element disposed between the intermediate platform and the lower structure and capable of rolling in a second direction intersecting the first direction. Further, the seismic isolation unit is formed in at least one of the lower surface of the upper structure or the upper surface of the intermediate platform in the first direction, has a stable point, and has the first point on both sides of the stable point. A first raceway surface for relatively rolling the rolling element toward a stable point by the action of gravity, and at least one of an upper surface of the lower structure or a lower surface of the intermediate base in the second direction; ,
A second raceway surface having a stable point and relatively rolling the second rolling element toward the stable point by the action of gravity on both sides of the stable point. At least three seismic isolation units are arranged between the lower structure and the upper structure so as to be separated from each other. The intermediate bases of the plurality of seismic isolation units are separated from each other and can be independently displaced, so that each intermediate base can secure free movement during vibration. In addition, since each intermediate stand is separated and independent from each other, even when the upper structure is bent by the overload, the bent upper structure as in the case of one common intermediate stand hits the intermediate stand. Such a phenomenon can be avoided.

Further, since the intermediate bases of the plurality of seismic isolation units are separated from each other, the dimensions of the intermediate bases are independent of the area of the place where the seismic isolation device is installed, that is, the area of the bottom of the upper structure. The dimensions of the intermediate platform can be arbitrarily reduced. Therefore, compared with a case where a plurality of intermediate bases are connected, the material of the intermediate base can be significantly reduced, and the cost can be reduced.

Further, since the intermediate stands are separated from each other, the plurality of seismic isolation units are completely separated from each other. Therefore, the seismic isolation unit can be easily handled. Further, the number of seismic isolation units to be used can be freely increased or decreased, and can be freely installed at desired locations. That is, the degree of freedom in the arrangement of the seismic isolation units can be increased.

The seismic isolation device according to claim 2 is the seismic isolation device according to claim 1, wherein the length of the first raceway surface along the first direction and the length of the second raceway surface The length along direction 2 is larger than the horizontal amplitude of the earthquake,
During an earthquake, the first rolling element and the second rolling element can roll without crossing the first raceway surface and the second raceway surface, respectively. Therefore, the first rolling element and the second rolling element do not deviate from the first track surface and the second track surface, respectively, during an earthquake, and can return to the stable point after the earthquake.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a building having a seismic isolation floor on which a seismic isolation device according to an embodiment of the present invention is installed.

FIG. 2 shows a state in which no load is applied to the floorboard of FIG.
II-II sectional view.

FIG. 3 is an II of FIG. 1 when an overload is applied to the floorboard.
-II sectional drawing.

FIG. 4 is an IV of FIG. 1 when a load is applied to the floorboard.
-IV line sectional drawing.

FIG. 5 is a sectional view taken along line VV of FIG. 1 showing a section of the seismic isolation unit constituting the seismic isolation device of FIG. 1;

FIG. 6 is a sectional view taken along line VI-VI of FIG. 1 showing another section of the seismic isolation unit constituting the seismic isolation device of FIG. 1;

FIG. 7 is a sectional view of the seismic isolation unit at the assumed maximum horizontal amplitude in FIG.

FIG. 8 is a sectional view showing a modification of the seismic isolation unit.

FIG. 9 is another sectional view of the seismic isolation unit of FIG.

FIG. 10 is an explanatory diagram showing a relationship between a track surface of one shape of the seismic isolation unit and a restoring force.

FIG. 11 is an explanatory view showing a relationship between a differently shaped track surface of the seismic isolation unit and a restoring force.

FIG. 12 is an explanatory view showing a relationship between a restoring force and a track surface of still another shape of the seismic isolation unit.

[Explanation of symbols]

U: seismic isolation unit, 11: lower stand (lower structure), 21: upper stand (upper structure), 40: middle stand, 50: upper roller (first)
Rolling elements), 60: lower rollers (second rolling elements), 43: first raceway surface, 13: second raceway surface.

Continued on the front page (72) Inventor Kunio Hayakawa 2-2-2 Matsuzaki-cho, Abeno-ku, Osaka City, Osaka Prefecture Inside Okumura Gumi Co., Ltd. (72) Inventor Ikuo Shimoda 1-3-2 Shiba-Daimon, Minato-ku, Tokyo OILES INDUSTRIES (72) Inventor Kiyoharu Suzuki 1-3-2 Shiba-Daimon, Minato-ku, Tokyo Oiles Industry Co., Ltd. (72) Inventor Masami Mochimaru 1-3-2 Shiba-Daimon, Minato-ku, Tokyo Oiles Industry Co., Ltd. Inside

Claims (2)

[Claims] 1. A first base, which is disposed between the intermediate base and the upper structure and is rotatable in a first direction.
A rolling element, and a second rolling element disposed between the intermediate base and the lower structure and capable of rolling in a second direction intersecting the first direction, further comprising the upper structure And has at least one of the upper surface of the intermediate platform in the first direction and has a stable point. On both sides of the stable point, the first rolling element is directed toward the stable point by the action of gravity. A first track surface to be relatively rolled, and at least one of an upper surface of the lower structure or a lower surface of the intermediate platform, formed in the second direction and having a stable point; A seismic isolation unit having a second raceway surface for relatively rolling the second rolling element toward a stable point by the action of gravity at a distance from the lower structure and the upper structure. Between at least three seismic isolation units The seismic isolation device is characterized in that the stand is separated from each other and can be displaced independently. 2. The seismic isolation device according to claim 1, wherein a length of the first track surface along the first direction and a length of the second track surface along the second direction are: A seismic isolation device characterized by having a magnitude greater than the horizontal amplitude of the earthquake.