JP2006112604A - Base isolating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base isolating device having simple construction with low manufacturing cost for developing stable base isolating performance. <P>SOLUTION: The base isolating device comprises an upper plate 7 provided on the upper side of a lower plate 5 at a space therefrom, a plurality of rolling bearings 8 mounted on one of the upper plate 7 and the lower plate 5 and protruded to the other, and four coil springs 37 mounted between the lower plate 5 and the upper plate 7 and arranged extending perpendicular to one another. To each of the coil springs 37, initial tension is applied which is equivalent to a length half or more the permissible sliding distance of the rolling bearing 9. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a seismic isolation device.

The seismic isolation device protects structures by reducing the response acceleration of earthquakes, and various types of seismic isolation devices have been proposed. In particular, as a seismic isolation device for relatively lightweight structures such as computer-related equipment, cultural assets, medical equipment, etc., a device that is simple and inexpensive in structure and capable of exhibiting the seismic isolation effect from the stage where the seismic force is small is required. It has been.
As a seismic isolation device which solves this, what is shown, for example in patent documents 1 is proposed.
This consists of a slip-type seismic isolation mechanism and a rolling-type seismic isolation mechanism between the lower floor and the upper floor, and a parallel link mechanism that suppresses the rotation of the upper floor. A coil spring is attached between them.
A combination of a slip-type seismic isolation mechanism and a rolling-type seismic isolation mechanism enables the seismic isolation effect to be exhibited even with low acceleration vibration.

JP-A-6-33583 (paragraphs [0018] to [0029] and FIGS. 1 to 4)

  By the way, in what was shown by patent document 1, although some initial tension | tensile_strength is provided to the coil spring, it is not enough for a tensile force to act at all times. For this reason, since it is required to mount in consideration of the compressive force, there is a problem that the mounting structure needs to be devised, and that the lower floor is damaged when it is seismically isolated.

  In view of the above problems, an object of the present invention is to provide a seismic isolation device that has a simple structure, is inexpensive to manufacture, and can exhibit stable seismic isolation performance.

In order to solve the above problems, the present invention employs the following means.
That is, the seismic isolation device according to the present invention is attached to one of the upper plate and the lower plate that is provided above the lower plate with a space therebetween, and is provided to protrude toward the other. A plurality of sliding bearings, and at least four coil springs mounted between the lower plate and the upper plate and extending in orthogonal directions, the coil springs, An initial tension corresponding to a length of half or more of an allowable sliding distance of each sliding bearing is applied.

According to the present invention, the relative horizontal movement that occurs between the upper plate and the lower plate is caused by sliding friction that is generated when a plurality of sliding supports slide between one of the upper plate and the lower plate. It is attenuated using And the relative horizontal movement which arises in the upper plate and the lower plate by the tension of the coil spring arranged extending in the orthogonal direction is prolonged, and the upper plate and the lower plate are in the original positional relationship. Return to origin.
In the present invention, “at least four coil springs arranged extending in orthogonal directions” means that even if they are not directly connected to one point, they are pulled in four directions perpendicular to each other. It means that it is arranged so that force acts.

As described above, since the seismic isolation is achieved by the combination of the sliding bearing and the coil spring, the manufacturing cost can be reduced as compared with the case where an expensive means such as an arc rail or a spherical plate is employed.
In this case, each coil spring is provided with an initial tension corresponding to more than half of the allowable sliding distance of each sliding bearing, so even if there is relative horizontal movement that occurs between the upper plate and the lower plate. A tensile force always acts on the coil spring. For this reason, since it is not necessary to consider compressive force in the attachment structure of the both ends of a coil spring, a structure can be simplified. The manufacturing cost can be further reduced by using an inexpensive coil spring. Further, it is possible to prevent sagging caused by the fact that the axial force is no longer applied when the coil spring is expanded and contracted.

In the seismic isolation device according to the present invention, the initial tension T ₀ applied to the coil spring is 1.1 Δk or more when Δ is half of the allowable slip distance and k is a spring constant of each coil spring. It is characterized by being.

Thus, when the allowable slip distance is Δ and the spring constant of each coil spring is k, if the initial tension T _{0 applied} to the coil spring is applied to be 1.1Δk or more, the upper plate and the lower plate are The fluctuation range of the vibration period that varies depending on the direction of the relative horizontal momentum generated can be suppressed to within about 5% (about 10% in terms of the fluctuation range of the spring constant). For this reason, since it can be lengthened to a substantially constant vibration period regardless of the direction of relative horizontal motion generated between the upper plate and the lower plate, stable seismic isolation performance can be obtained.

In the seismic isolation device according to the present invention, the sliding bearing is a rolling bearing,
A friction damper for applying a damping force is provided between the upper plate and the lower plate.

  Thus, since the sliding bearing is a rolling bearing, the coefficient of static friction between the sliding bearing and the upper plate or the lower plate is reduced. Further, since the rolling bearing supports the load, the surface pressure between the friction damper and the upper plate or the lower plate is constant and can be arbitrarily adjusted. Since the coefficient of static friction can be reduced by adjusting the contact pressure to be small, the seismic isolation effect can be exhibited even with a small acceleration. Further, the amount of rolling can be effectively suppressed by applying a damping force by the friction damper.

  The seismic isolation device according to the present invention is characterized in that the sliding bearing is composed of a combination of a rolling bearing and a friction bearing.

Thus, since the sliding bearing is composed of a combination of a rolling bearing and a friction bearing, the frictional force of the sliding bearing is smaller than that of the friction bearing alone. For this reason, the seismic isolation effect can be exhibited even with a vibration having a small acceleration as compared with the case of only the friction bearing.
Further, since the bearing displacement can be suppressed by the frictional force of the friction bearing, it is not necessary to use a separate friction damper, so that the manufacturing cost can be reduced.

  In the seismic isolation device according to the present invention, the sliding bearing is a rolling bearing, and a rolling friction enhancing member is provided on a surface of the upper plate or the lower plate on which the rolling bearing rolls. .

As described above, since the rolling friction enhancing member is provided on the surface of the upper plate or the lower plate on which the rolling bearing rolls, the rolling resistance increases when the rolling bearing rolls. When the rolling resistance increases, the rolling displacement is suppressed and damped, so that it is not necessary to use a damping member such as a friction damper or a friction bearing, and the manufacturing cost can be reduced correspondingly.
The rolling friction enhancing member is made of a coating material excellent in elasticity, wear resistance and adhesion, such as a polyurethane resin, or a rubber-based or fiber-based flexible sheet material (for example, nylon fiber). Installed by sticking.

  In the seismic isolation device according to the present invention, the rolling friction enhancing member is provided in the vicinity of the boundary of the allowable rolling range.

  As described above, since the rolling friction enhancing member is provided near the boundary of the allowable rolling range, the resistance is increased and the displacement is suppressed only when the displacement exceeding the allowable rolling range occurs, such as during an extremely rare earthquake. Therefore, the seismic isolation effect can be exhibited from earthquakes with low acceleration and frequent occurrence.

  According to the seismic isolation device of the present invention, a combination of a sliding bearing and a coil spring is used to make a seismic isolation, and the coil spring is given an initial tension corresponding to a length of more than half of the allowable sliding distance of each sliding bearing. Therefore, the structure is simple, the manufacturing cost is low, and stable seismic isolation performance can be exhibited.

Below, the seismic isolation apparatus 1 concerning one Embodiment of this invention is demonstrated with reference to FIGS.
FIG. 1 is a perspective view showing a state in which the seismic isolation device 1 according to the present embodiment is installed. Examples of the seismic isolation object 3 include computer-related equipment such as server racks, cultural properties, medical equipment, and structures such as buildings.

FIG. 2 is a plan view of the seismic isolation device 1, with the left half showing a lower plate plan and the right half showing an upper plate plan. FIG. 3 is a front view of the seismic isolation device 1 in the XX view of FIG. FIG. 4 is a side view of the seismic isolation device 1.
The seismic isolation device 1 is interposed between a lower plate 5 placed on the floor, an upper plate 7 disposed above the lower plate 5 with a space therebetween, and the lower plate 5 and the upper plate 7. Four rolling bearings 9, four friction dampers 11 interposed between the lower plate 5 and the upper plate 7, and a restoring member 13 interposed between the lower plate 5 and the upper plate 7. And are provided.

The lower plate 5 is formed by arranging two sets of steel slide plates 6 stacked on a steel base plate 4, and connecting them together by a metal fitting 17.
The sliding plate 6 of the lower plate 5 is made of chrome molybdenum steel with high hardness.
The upper plate 7 is made of steel, and is configured by combining a loading plate 19 and a mounting plate 21 provided with two sets of intervals.
Each loading plate 19 loads the seismic isolation object 3, and two rectangular openings 23 are juxtaposed at the center thereof.
On the upper surface of the mounting plate 21, a spacing holding portion 25 is provided to hold the spacing with the loading plate 19 having a substantially rectangular cross section so as to surround the opening 23 of the loading plate 19. Both ends in the longitudinal direction of the interval holding part 25 are extended, and a flange 27 is provided at one end. Adjacent flanges 27 are joined together to integrate the upper plate 7.
The plane size of the upper plate 7 and the lower plate 5 is, for example, 1200 mm × 1200 mm.

At the four corners of the seismic isolation device 1, there are provided suspension bolts 29 that are provided so as to penetrate the mounting plate 21 and whose lower ends are screwed onto nuts fixed to the lower plate 5. A hanging eye nut 31 is attached to the upper end of the hanging bolt 29.
The rolling bearing 9 and the friction damper 11 are respectively arranged at positions corresponding to the opening 23 of the mounting plate 21 along the longitudinal direction 8 of the opening 23 so that the friction damper 11 is arranged inside and the rolling bearing 9 is arranged outside. Yes.
The rolling bearing 9 is designed to move within the area 33 and the friction damper 11 is designed to move within the area 35. The radius Δ of the area 33 corresponds to half of the allowable slip distance.

The restoring member 13 includes a lower mounting member 39 attached to each of the upper four corners of the sliding plate 6 (lower plate 5) and a lower surface of the mounting plate 21 (upper plate 7), respectively, along the sides at the center of the four sides. A pair of upper mounting members 41 arranged side by side, a lower mounting member 39 whose both ends are adjacent, and a coil spring 37 mounted on the upper mounting member 41 are provided.
Therefore, each coil spring 37 is attached between the upper plate 7 and the lower plate 5.
Two coil springs 37 are arranged in series on each of the four sides of the seismic isolation device 1. Therefore, each one of the coil springs 37 disposed on the adjacent sides is disposed in the orthogonal direction, and one end thereof is attached together with the lower mounting member 39 provided at the corner. The four coil springs 37 extended in the orthogonal direction according to the present invention are constituted by the four coil springs 37 arranged diagonally.
Coil spring 37 is attached as a set length L is extended by the length L _T tensile from the free length.
Tensile length L _T is set to 1.1 times the length of the radius Δ of area 33.

The friction damper 11 will be described with reference to FIG.
The friction damper 11 includes a damper cylinder 43 provided through the mounting plate 21, a spring guide 45 loosely fitted inside the damper cylinder 43, a compression coil spring 47 disposed inside the spring guide 45, A sliding member 49 attached to the lower surface of the spring guide 45 is provided.
The damper cylinder 43 has a hollow cylindrical shape with an open lower surface. The damper cylinder 43 is fixedly attached at its axial intermediate portion by a rectangular parallelepiped-shaped attachment member 51 fixedly attached to the lower surface of the attachment plate 21.
The spring guide 45 has a substantially hollow cylindrical shape with an open upper surface, and is loosely fitted inside the damper cylinder 43.
The compression coil spring 47 is disposed inside the spring guide 45 and between the upper portion of the damper cylinder 43 and the lower portion of the spring guide 45, and the spring guide 45, that is, the sliding member 49 is directed toward the sliding plate 6. It is configured to be energized.
The sliding member 49 is made of, for example, tetrafluoroethylene resin.

The rolling bearing 9 will be described with reference to FIG.
The rolling support 9 has a rectangular parallelepiped attachment member 53 attached to the lower surface of the attachment plate 21, a main body 55 attached so as to protrude downward from the lower central portion of the attachment member 53, and a lower part of the main body 55. A ball bearing 57 provided movably is provided.
The ball bearing 57 is not limited to one, and a plurality of ball bearings 57 may be provided.

The operation of the seismic isolation device 1 according to this embodiment described above will be described.
The seismic isolation device 1 is brought into a state in which the mounting plate 19 and the lower plate 5 of the upper plate 7 are not moved relative to each other with the suspension bolt 29 attached, with the loading plate 19 not attached.
The seismic isolation device 1 is hung by hanging a rope around the eyenut 31 and moved and installed at an installation location. This may be lifted and moved without using the eyenut 31.
Then, the suspension bolt 29 is removed, and the loading plate 19 is attached. Thereafter, the seismic isolation object 3 is placed on the loading plate 19 and the installation is completed.
In addition, you may make it carry in in the state in which the loading board 19 was mounted | worn from the beginning.

Next, the seismic isolation operation will be described.
When acceleration (inertial force) acts on the upper plate 7 and the lower plate 5 due to the earthquake, the upper plate 7 supported by the rolling bearing 9 and made longer by the coil spring 37, and the sliding plate 6 of the lower plate 5 Relative displacement occurs between the two. This relative displacement occurs because the upper plate 7 having a long period cannot follow the movement of the lower plate 5, and the upper plate 7 seems to be stopped against the lower plate 5 that moves as fast as the earthquake motion. Seismic isolation effect is demonstrated.
At this time, as the friction damper 11 moves, the sliding member 49 pressed against the sliding plate 6 by the compression coil spring 47 moves, so that sliding friction occurs between the sliding member 49 and the sliding plate 6. To do.
The horizontal force generated between the upper plate 7 and the lower plate 5 is attenuated by the frictional force generated by this friction, and a seismic isolation effect can be obtained while effectively suppressing the amount of movement of the rolling bearing.

Next, the operation of the restoring member 13 will be described.
The eight coil springs 37 are all attached with substantially the same initial tension T ₀ . Since the four coil springs 37 arranged diagonally are arranged so as to extend in directions orthogonal to each other, the upper plate 7 and the lower plate 5 overlap each other as shown in FIG. The force of the coil spring 37 is balanced.
When a relative horizontal displacement occurs between the upper plate 7 and the lower plate 5, this force balance is broken, and the total force by the eight coil springs acts in a direction to restore the displacement.
This reduces the amplitude of vibration, while increasing the period of vibration. And when a vibration is settled, the tensile force of each coil spring 37 will be returned to the position before the stable displacement.

  In this way, the combination of the rolling bearing 9, the friction damper 11 and the coil spring 37 provides the base isolation so that the manufacturing cost can be reduced as compared with the case where an expensive means such as an arc rail or a spherical plate is employed. Can do.

The length of each coil spring 37 is a set length L that is extended by a length L _T tensile from the free length. The tensile length L _T, which are set to 1.1 times the radius Δ of the area 33 which movement is allowed in the design of the sliding bearings 9, relative between the upper plate 7 and the bottom plate 5 Even if a horizontal displacement occurs, a tensile force is always applied to each coil spring 37 as long as the vibration acceleration (inertial force) is within the range assumed in the design.
For this reason, since it is not necessary to consider compressive force in the attachment structure of the both ends of the coil spring 37, an attachment structure can be simplified. The manufacturing cost can be further reduced by using an inexpensive coil spring. Further, it is possible to prevent sagging caused by the fact that the axial force is no longer applied when the coil spring is expanded and contracted.

Next, selection of the coil spring 37 will be described including the concept of the initial tension T _{0 applied} thereto.
In FIG. 7, the intersection of four coil springs 37 (k is a single spring constant) arranged orthogonally with an initial tension T ₀ from the balanced initial position (0, 0). A state of moving to a position (X, Y) is shown.
The balance of force at this time is expressed by equation (1).

また、ばねセット長Ｌ、初期張力Ｔ_０を与えるためのばね引張長さをＬ_Ｔ（＝セット長Ｌからばねの自由長を除いた長さ）として、Δに対する比率をそれぞれ下式で表わし、

これを式（２）に代入すると、式（３）が得られる。

また、ばね単体のばね定数ｋに対する０度方向の系全体のばね定数Ｋ_０の比は、式（４）で表わすことができる。

When the allowable half amplitude (the radius of the area 33) is Δ and the set length of the spring is L, the load F ₀ when Δ is displaced in the 0 degree direction (X direction in the spring axis direction) is obtained from the equation (1). It is represented by Formula (2).

Further, the spring set length L, the spring tension length for giving the initial tension T ₀ is L _T (= the length obtained by subtracting the free length of the spring from the set length L), and the ratio to Δ is expressed by the following equations,

Substituting this into equation (2) yields equation (3).

Further, the ratio of the spring constant K ₀ of the whole system in the 0 degree direction to the spring constant k of the single spring can be expressed by Expression (4).

式（４）の０度方向ばね定数と式（５）の４５度方向のバネ定数は、α＝βの条件時のみ等しくなるが、物理的にはＬ_Ｔ＜Ｌの関係、即ちα＜βの関係があるため、０度方向と４５度方向のばね定数には誤差が出てくる。
図８に、βをパラメータとして、Ｋ_４５／Ｋ_０とαとの関係を示している。
０度方向と４５度方向の固有周期の誤差が５％程度(ばね定数の誤差でみると１０％程度)であれば性能的に大きな問題にならないこと、α=1.1程度の場合、この誤差に対するβの影響が少なくなることから、下記初期張力Ｔ₀を加えることで、ばねの方向性誤差を抑えることが可能である。

According to the same procedure as described above, the ratio of the spring constant K ₄₅ of the entire system in the 45-degree direction to the single spring constant k is expressed by Expression (5).

The spring constant in the 0 degree direction in Expression (4) and the spring constant in the 45 degree direction in Expression (5) are equal only when α = β. However, physically, the relationship L _T <L, that is, α <β. Therefore, an error appears in the spring constants in the 0 degree direction and the 45 degree direction.
FIG. 8 shows the relationship between K ₄₅ / K ₀ and α using β as a parameter.
If the error of the natural period in the 0 degree direction and the 45 degree direction is about 5% (about 10% in terms of the error of the spring constant), it will not be a big problem in terms of performance. Since the influence of β is reduced, it is possible to suppress the directional error of the spring by applying the following initial tension T ₀ .

Considering the above points, the coil spring 37 is designed as follows.
First, the 0 degree direction spring constant K ₀ of the entire system corresponding to the seismic isolation cycle is set. Next, a half amplitude (radius of area 33) Δ allowed at the time of seismic isolation is set. Thereafter, α and β are determined, and the spring constant of the single spring is obtained from Equation (4).

In the present embodiment, since the tensile length _{L T} is a 1.1Deruta, initial tension _{T 0} applied to the coil spring 37 has a 1.1Derutak.
For this reason, the fluctuation range of the spring constant integrated with the coil springs that vary depending on the direction of relative horizontal movement generated between the upper plate 7 and the lower plate 5 can be suppressed to about 10%. Therefore, the natural period at the time of base isolation that is inversely proportional to the square root of the overall strength of each coil spring 37 is substantially constant regardless of the direction of the relative horizontal motion generated between the upper plate 7 and the lower plate 5. Therefore, the seismic isolation device 1 can obtain stable seismic isolation performance.

[Second Embodiment]
Next, a second embodiment of the present invention will be described using FIG. 9 and FIG.
In this embodiment, the basic configuration is the same as that of the first embodiment, except that the configuration of a sliding bearing that performs a damping action and the friction damper 11 is not used. Therefore, in this embodiment, the point which is different from 1st embodiment is demonstrated and the overlapping description is abbreviate | omitted about another part.
In addition, the same code | symbol is attached | subjected to the component same as 1st embodiment, and the detailed description is abbreviate | omitted.

In the present embodiment, two rolling bearings 9 and two friction bearings 61 are used as sliding bearings. The two rolling bearings 9 are arranged on one diagonal line of the seismic isolation device 1 and the two friction bearings 61 are arranged on another diagonal line. It is installed at the point target position.
The friction bearing 61 will be described with reference to FIG.
The friction bearing 61 has a rectangular parallelepiped attachment member 63 attached to the lower surface of the attachment plate 21, a substantially cylindrical main body 65 attached to the lower central portion of the attachment member 63 so as to protrude downward, and a main body 65. And a friction member 67 attached to the lower part of the motor.
As the friction member 67, for example, a plate material made of tetrafluoroethylene resin is used. The friction member may be made of hard plastic or metal material, and the sliding surface with the sliding plate 6 may be coated with tetrafluoroethylene resin.

The operation of the seismic isolation device 1 according to this embodiment described above will be described.
Since the installation of the seismic isolation device 1 and the operation of the restoring member are the same as those in the first embodiment described above, a duplicate description is omitted.
Therefore, here, the seismic isolation operation will be mainly described.
When acceleration (inertial force) acts on the upper plate 7 and the lower plate 5 due to the earthquake, the sliding plate of the upper plate 7 and the lower plate 5 supported by the rolling bearing 9 and the friction bearing 61 and having a long period by the coil spring 37. A relative displacement occurs between 6 and 6. This relative displacement occurs because the upper plate 7 having a long period cannot follow the movement of the lower plate 5, and the upper plate 7 seems to be stopped against the lower plate 5 that moves as fast as the earthquake motion. Seismic isolation effect is demonstrated.
At this time, as the friction bearing 61 moves, the friction member 67 slides on the sliding plate 6, so that sliding friction occurs between the friction member 49 and the sliding plate 6.
Due to the frictional force generated by this friction, the horizontal movement generated between the upper plate 7 and the lower plate 5 is attenuated, and the seismic isolation effect can be obtained while effectively suppressing the relative displacement.

  As described above, the combination of the rolling bearing 9 and the friction bearing 61 exerts a seismic isolation effect. Therefore, the overall static friction coefficient of the sliding bearing is larger than that of the rolling bearing 9 alone, but the friction bearing 61 Smaller than the only one. For this reason, the seismic isolation effect can be exhibited even with a vibration having a small acceleration compared to the case of only the friction bearing.

As a mechanism for performing the seismic isolation action, the first embodiment uses a combination of the rolling bearing 9 and the friction damper 11, and the second embodiment uses a combination of the rolling bearing 9 and the friction bearing 61. It is not limited and various forms are used.
For example, only the rolling bearing 9 may be used. Although it is conceivable that the vibration damping effect cannot be sufficiently exerted only by the rolling support 9, in that case, the material of the sliding plate 6 is, for example, a rubber-based, fiber-based, or resin-based flexible sheet material. Alternatively, these materials are applied to the upper surface of the sliding plate 6 or a coating material excellent in elasticity, wear resistance and adhesion is applied.
By doing so, the rolling resistance increases when the rolling bearing 9 rolls on the sliding plate 6. When rolling resistance increases, the vibration is effectively attenuated, so that the seismic isolation effect can be improved.

It is a perspective view which shows the seismic isolation system using the seismic isolation apparatus of 1st embodiment of this invention. It is a fragmentary sectional view which shows the plane structure of the seismic isolation apparatus of 1st embodiment of this invention. It is XX sectional drawing of FIG. FIG. 3 is a side view of FIG. 2. It is a longitudinal cross-sectional view which shows the friction damper of 1st embodiment of this invention. It is a longitudinal cross-sectional view which shows the rolling bearing of 1st embodiment of this invention. It is a graph explaining the function of the coil spring of 1st embodiment of this invention. It is a graph which shows the directivity of the spring multiplier of the coil spring of 1st embodiment of this invention. It is a fragmentary sectional view which shows the plane structure of the seismic isolation apparatus of 2nd embodiment of this invention. It is a fragmentary sectional view which shows the friction bearing of 2nd embodiment of this invention.

Explanation of symbols

1 Seismic isolation device 5 Lower plate 7 Upper plate 9 Rolling bearing 11 Friction damper 37 Coil spring 61 Friction bearing

Claims (6)

An upper plate spaced above the lower plate;
A plurality of sliding bearings attached to any one of the upper plate and the lower plate and projecting toward the other;
And at least four coil springs attached between the lower plate and the upper plate, each extending in an orthogonal direction, and
The seismic isolation device, wherein the coil spring is provided with an initial tension corresponding to a length of half or more of an allowable sliding distance of each sliding bearing. The initial tension T ₀ to be applied to the coil spring, a half of the permissible sliding distance delta, the spring constant of each coil spring when a k, to claim 1, characterized in that at least 1.1Δk The described seismic isolation device. The sliding bearing is a rolling bearing,
The seismic isolation device according to claim 1, wherein a friction damper that applies a damping force is provided between the upper plate and the lower plate. The seismic isolation device according to claim 1 or 2, wherein the sliding bearing is composed of a combination of a rolling bearing and a friction bearing. The sliding bearing is a rolling bearing,
The seismic isolation device according to claim 1 or 2, wherein a rolling friction enhancing member is provided on a surface of the upper plate or the lower plate on which the rolling bearing rolls. The seismic isolation device according to claim 5, wherein the rolling friction enhancing member is provided in the vicinity of a boundary of an allowable rolling range.

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