JP2002061704A - Gravity restorable base isolation structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate vertical displacement of an upper structure part 2 by horizontal directional vibration in a gravity restorable base isolation structure 3 by an eccentric roller bearing 4 for restoring the upper structure part 2 to an origin position to a lower structure part 1 by the dead weight. SOLUTION: A vertical displacement negating means (a rack 6) is provided for negating vertical directional displacement of the upper structure part 2 in a base isolation restoring process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gravity-restoring seismic isolation structure.

[0002]

2. Description of the Related Art Various types of conventional gravity restoring seismic isolation devices, such as those using eccentric roller bearings and those using rolling bearings using steel balls and upper or lower inner spherical or conical trays, are used. There is. With this type of seismic isolation device, when horizontal vibration occurs in the lower structure due to an earthquake or the like, the upper structure and the lower structure are caused to move relative to each other, preventing the horizontal vibration from being transmitted to the upper structure. Then, the upper structure is restored to its original position with respect to the lower structure by its own weight.

[0003] However, the conventional gravity restoring seismic isolation device as described above has a problem in that the upper structure is repeatedly displaced up and down during seismic isolation and restoration. This problem is caused, for example, by increasing the mechanical load on each part of the upper structure when the upper structure is a residential building and the lower structure is the foundation thereof, or When the part is made of a heavy material, a problem such as applying a large mechanical load to the seismic isolation structure occurs.

Therefore, in order to reduce the amount of vertical displacement of the upper structure, the eccentric distance of the roller is reduced in the case of the eccentric roller bearing, and the curvature of the inner surface of the tray in the case of the rolling bearing. It is conceivable to increase the radius or make the inclination of the inner surface of the saucer gentle, but there are limitations.

According to the present invention, in the technical background as described above, the vertical displacement of the upper structure due to the horizontal vibration can be eliminated, and for example, the mechanical load on the upper structure, the seismic isolation structure and the like can be eliminated. It is an object of the present invention to provide a gravity-restoring seismic isolation structure capable of exhibiting effects such as minimizing the vibration.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide an upper structure which is interposed between an upper structure and a lower structure and which allows the relative displacement of the upper and lower structures due to horizontal vibration to permit seismic isolation. In the gravity-restoring seismic isolation structure, the part is restored to the origin position with respect to the lower structure part by its own weight.
A gravity restoring seismic isolation structure is provided, which comprises vertical displacement canceling means for canceling the vertical displacement of the upper structure in the seismic isolation / restoration process.

In this gravity restoring seismic isolation structure, since the upper structure is restored to the origin position with respect to the lower structure by its own weight, a vertical displacement canceling means is provided. The upper structure is not displaced up and down during the process of seismic isolation and restoration due to horizontal vibration caused by an earthquake or the like. Therefore, for example, the mechanical load on the upper structure can be reduced, and the mechanical load on the seismic isolation structure itself can be reduced even when the weight of the upper structure is large. be able to.

[0008]

Next, embodiments of the present invention will be described with reference to the drawings.

The gravity-restoring seismic isolation structure of the embodiment shown in FIG. 1 is based on eccentric roller bearings, and the present embodiment is a case where it is used for seismic isolation of a building such as a detached house. . 1 is a foundation as a lower structure, 2 is a building body as an upper structure, and 3 is a seismic isolation structure.

The seismic isolation structure 3 includes an eccentric roller 4, a linear rail 5, and a rack 6 as a means for canceling the vertical displacement. The rail 5 is attached to the upper surface of the foundation 1, and the rack 6 is attached to the lower surface of the building body 2 by the tooth surface 6.
a is attached downward.

The eccentric roller 4 is a large circle first roller 8.
And a second roller 9, 9 having a smaller circle than the first roller 8. The second roller 9, 9 has its central axis C9 oriented parallel to the central axis C8 of the first roller 8, and The first roller 8 is provided on both sides of the first roller 8 so as to operate integrally with the first roller 8 eccentrically from the center axis C8 of the first roller 8. That is, the second rollers 9, 9 are rotated by the rotation of the first roller 8 while revolving around the center C <b> 8 of the first roller 8. Note that there is no particular limitation on the magnitude relationship between the diameters of the first roller 8 and the second rollers 9, 9, and they may have the same diameter, or the second roller 9 may have a larger diameter than the first roller 8. It may consist of things.

An annular groove 8a extending in the circumferential direction for fitting the rail 5 is provided on the outer peripheral portion of the first roller 8, and the second rollers 9, 9 are provided on the outer peripheral surface thereof.
Tooth surfaces 9a, 9a that can mesh with the tooth surfaces 6a of the curved rack 6 are formed and are pinions.

The rack 6 is formed in a curved shape in which the central portion on the tooth surface 6a side is convex downward, and this acts to cancel the vertical displacement of the building body 2 during horizontal vibration. Has become.

The eccentric roller 4 is mounted on the rail 5 so that the first roller 8 fits the outer peripheral annular groove 8a on the rail 5, and the second roller 9 of the eccentric roller 4 , 9 from above, the rack 6 on the lower surface of the building body 2 is placed so as to mesh with the outer peripheral tooth surfaces 9a, 9a to form a seismic isolation structure.
In this seismic isolation structure, the second roller 9 of the eccentric roller 4 has its center axis C9 due to its own weight.
Is located just below the central axis C8 of the first roller 8 and is in a stable state. At this time, due to the meshing action between the tooth surface 9 a of the second roller 9 and the tooth surface 6 a of the rack 6, the downward convex top at the center of the lower surface of the rack 6 is held on the outer peripheral upper surface of the second roller 9.

From this state, for example, due to an earthquake,
When vibration occurs in the horizontal direction, as shown in FIGS. 2 to 5, seismic isolation is performed without displacing the building body 2 up and down, and horizontal vibration of the foundation 1 is transmitted to the building body 2 side. Is prevented.

That is, as shown in FIGS. 2 (a) to 3 (d), when the base 1 is displaced horizontally by vibration to the right as indicated by the arrow, the first roller 8 is rotated counterclockwise. Accordingly, the second roller 9 is moved to the center C of the first roller 8.
The second roller 9 revolves counterclockwise around the circumference of the roller 8 to perform upward displacement. However, since the second roller 9 rotates counterclockwise at the same time, the rotation causes the rack 6 to be displaced rightward from the downwardly directed top portion of the center of the rack 6, thereby increasing the displacement of the second roller 9. To prevent the building body 2 from being displaced upward.

When the foundation 1 has exhausted the horizontal displacement in the right direction in the state shown in FIG. 3D, this time, due to the own weight of the building main body 2, FIGS. As shown in the figure, the second roller 9 revolves clockwise around the center C8 of the first roller 8 in the right direction and restores toward the origin position.
The roller 9 is displaced downward. However, since the second roller 9 rotates clockwise at the same time, the second roller 9 is displaced leftward toward the downward top portion of the center of the rack 6 by this rotation, whereby the second roller 9 is rotated. The descending displacement is canceled, and the building body 2 is restored while preventing the descending displacement.

Then, as shown in FIGS. 4 (h) to 5 (w), the same operation is performed in the opposite direction, and the base is restored to the stable state shown in FIG. In the seismic isolation / restoration process, the building body 2 is not displaced up and down. Therefore, the mechanical load applied to each part of the building main body 2 which is the upper structure is kept small, and even if the upper structure is heavy such as the building main body 2, the seismic isolation / restoration is performed. In the process, the mechanical load on the seismic isolation structure 3 is also reduced.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention. For example, in the above-described embodiment, the case where the base structure is used as the base, the upper structure is used as the building main body, and the seismic isolation structure is formed between them, but not limited to the building, various structures may be used. May be used in objects. Also, the present invention is not limited to the case where the horizontal vibration of the lower structure is used as a seismic isolation structure for preventing the horizontal vibration from being transmitted to the upper structure. It may be used as a seismic isolation structure for preventing transmission of vibration. Alternatively, it may be used as a seismic isolation structure for preventing horizontal vibration of the upper structure from transmitting to the lower structure and preventing horizontal vibration of the lower structure from transmitting to the upper structure. In the above-described embodiment, the central portion of the tooth portion 6a on the lower surface of the downward rack 6 is formed in a downwardly convex curved line, and this is used as a vertical displacement canceling means. 5 may be a curved rail having a downward convex shape, and this may be used as a vertical displacement canceling means. Further, in the present invention, the first roller 8 is attached to the lower structure 1, and the second roller 9 is attached to the upper structure 2.
However, it is only necessary to be configured so that each rolls without slipping, and not only the non-slip rolling mechanism using the rack and pinion mechanism as described above, but also various non-slip rolling mechanisms such as those using frictional force are adopted. May be. Further, in the above embodiment, the case where the present invention is applied to the seismic isolation structure of the eccentric roll bearing is shown. However, the present invention can also be applied to the seismic isolation structure of the rolling bearing. It may be used for various gravity restoring seismic isolation structures that are designed to restore the lower structure part to the origin position. When it is necessary to perform seismic isolation in the horizontal two-dimensional direction, the above-mentioned seismic isolation structure can be combined in two levels up and down by 90 degrees in the horizontal direction to form a seismic isolation structure. Therefore, such horizontal two-dimensional vibration can be effectively isolated.

[0020]

As described above, the present invention is a gravity-restoring seismic isolation structure in which the upper structure is restored to the origin position by its own weight, but the upper structure is caused by horizontal vibration. The vertical displacement of the part can be eliminated,
Therefore, for example, the mechanical load on each part of the upper structure can be reduced, and even when the upper structure is heavy, the mechanical load on the seismic isolation structure is reduced. Can be suppressed.

[Brief description of the drawings]

FIG. 1 shows a gravity recovery type seismic isolation structure of an embodiment.
FIG. 1A is a sectional front view, and FIG. 2B is a sectional view taken along line II.

FIGS. 2A to 2C are cross-sectional front views sequentially showing the seismic isolation operation state together with FIGS. 3 to 5. FIG.

FIGS. 3 (d) to (f) are sectional front views sequentially showing the seismic isolation operation state together with FIGS. 2, 4 and 5. FIG.

FIGS. 4 (g) to 4 (l) are sectional front views sequentially showing the seismic isolation operation state together with FIGS. 2, 3 and 5. FIG.

5 (a) to 5 (a) are sectional front views sequentially showing the seismic isolation operation state together with FIGS. 2 to 4. FIG.

[Description of Signs] 1… Foundation (lower structure part) 2… Building body (upper structure part) 3… Seismic isolation structure part 6… Rack (vertical displacement canceling means) 6a… Tooth part

Claims (1)

[Claims] 1. An upper structure is interposed between an upper structure and a lower structure to permit seismic isolation by allowing relative displacement of the upper and lower structures due to horizontal vibration, and the upper structure is attached to the lower structure by its own weight. On the other hand, in the gravity restoring seismic isolation structure that is restored to the origin position, a vertical displacement canceling means for canceling the vertical displacement of the upper structure part in the above seismic isolation and restoration process is provided. Gravity restoration type seismic isolation structure characterized by the following.