JP2013249946A - Seismic isolator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a greatly excellent seismic isolator capable of providing rolling bearing at low cost.SOLUTION: A seismic isolator is a rolling seismic isolator in which horizontal resistant force is low when a building quakes in a horizontal direction and repeatedly moves by the quakes of an earthquake. The seismic isolator has a planar steel plate 6 and a main steel ball 1 turnably placed on a planar surface of the planar steel plate and is constituted by steel ball groups 2, 3 holding the main steel ball on the same planar face in a certain positional relation respectively and held by retainers for turnably holding all the steel balls turnably covering the upper side of the main steel ball. The seismic isolator exhibits an effect to quakes in a horizontal direction of the earthquake.

Description

Detailed Description of the Invention

  In order to protect the structure from strong ground motion during a large earthquake, various seismic isolation devices (various laminated rubber, sliding bearings, rolling bearings, etc.) are placed between the ground and the structure, and the vibration of the ground directly Seismic isolation structures that prevent transmission are in practical use. The present invention relates to a rolling seismic isolation device considered to be able to provide the lowest horizontal resistance force among these seismic isolation devices.

The seismic isolation structure can reduce the vibration of the structure itself against strong earthquake motion during a large earthquake, so it not only increases the seismic safety of the structural framework of the building, but also prevents the fall of contained items such as internal furniture and equipment. The risk of falling / collision is reduced, and the seismic safety of the entire building can be dramatically improved. The advent of seismic isolation devices has made it possible to realize seismic isolation buildings that have superior seismic safety performance compared to conventional seismic structures, and the following seismic isolation devices have been put into practical use. In other words, as a seismic isolation system having both isolator function and damper function, (1) natural rubber laminated rubber + separate damper, (2) high damping laminated rubber, (3) laminated rubber with lead plugs are adopted in Japan. In addition to this, in recent years, (4) slip-supporting seismic isolation devices using a combination of PTFE (teflon) materials and stainless steel plates have been gradually adopted.
Furthermore, in recent years, as a method for improving and improving the seismic isolation performance of a seismic isolation structure, a seismic isolation structure using both a rolling bearing and a laminated rubber bearing according to Japanese Patent No. 2603426 has been realized. ing. However, the adoption of rolling bearings has only recently been addressed, and trials are being conducted on lightweight structures such as houses, and full-scale rolling seismic isolation that supports heavy structures. The actual situation is that the method of realizing the bearing has not been established.

Problems to be solved by the invention

Examples of rolling seismic isolation devices that have been put to practical use so far include a device that uses only one relatively large-diameter steel ball as shown in FIG. 1 (referred to as device A) and a large number of small-diameter steel balls shown in FIG. There is a method of using a linear motion system (referred to as “device B”) that travels on a straight track (rail) by circulating motion in a box-shaped cage in which it is incorporated in two perpendicular directions. Both the device A and the device B require a box-type cage in which a large number of small-diameter steel balls are incorporated in a state in which a circulating motion is possible, thereby making the seismic isolation device expensive.
On the other hand, since the seismic isolation device is installed at the base portion of the heavy structure, a very large load is applied, and there is a high possibility that the mechanism and material properties for reducing the vibration of the earthquake cannot be effective.
An object of the present invention is to realize a method for realizing this rolling support as an extremely excellent seismic isolation device capable of providing at low cost.

Means for solving the problem

The seismic isolation device of the present invention has the appearance shown in FIG. 1B, and FIG. 1A is a cross-sectional view taken along the section AA in FIG. When the diameter of the main steel ball 1 is a, the diameter of the circle formed by the first small-diameter steel ball group is b smaller than a, and the second small-diameter steel ball group is constituted by b. A small-diameter steel ball group 3 having a circle diameter c smaller than a, an upper member 4 that holds the small-diameter steel ball group 2 and covers the main steel ball 1 in a rotatable state, and a small-diameter steel ball group 3. It is comprised from the lower member 5 accommodated in the steel ball 1 in the state which can rotate, and the steel plate 6 laid on the foundation structure material 8. As shown in FIG.
Due to the above configuration, the seismic isolation device according to the present invention is configured such that the main steel ball 1 is fixed by the four corner screws 7 between the upper member 4 and the lower member 5 that are covered, and the building foundation 8 and the foundation structural material 9 It is installed between.
The operation of seismic isolation according to the present invention will be described with reference to FIG. When an earthquake occurs, the ground rolls, and the building foundation 8 moves in the direction of the arrow 11 shown in FIG. 2A (from right to left), it is mainly caused by friction with the steel plate 6 fixed to the foundation 8. The steel ball 1 generates a rotational force counterclockwise as indicated by an arrow 11 '. At this time, since the rolling resistance is reduced by the small-diameter steel ball group 2, the upper member 4 does not move without being dragged by the main steel ball 1. Since the rolling resistance is reduced by the small-diameter steel ball group 3, the lower member 5 does not move without being dragged by the main steel ball 1. Conversely, as shown in FIG. 2 (b), when the building foundation 8 moves in the direction of the arrow 12 (from left to right), the main steel ball is caused by friction with the steel plate 6 fixed to the foundation 8. 1 generates a rotational force clockwise as indicated by an arrow 12 '. At this time, since the rolling resistance is reduced by the small-diameter steel ball group 2, the upper member 4 does not move without being dragged by the main steel ball 1. Since the rolling resistance is reduced by the small-diameter steel ball group 3, the lower member 5 does not move without being dragged by the main steel ball 1.
Thus, even if a roll due to an earthquake occurs, the roll is attenuated by the seismic isolation device of the present invention, and the building is not shaken because the roll is hardly transmitted to the foundation structural member 9 of the building.
On the other hand, since the seismic isolation device of the present invention is provided with the first and second small-diameter steel ball groups, the load on the building per one small-diameter steel ball is reduced, so the durability of the seismic isolation device is reduced. As it increases, the rotation of the main steel ball 1 also becomes smooth.
FIG. 3 shows basic components of the seismic isolation device of the present invention.
FIG. 4 shows an example of a method for joining the steel plate 6 and the building foundation material 8. As a coupling method, it is considered that the fixing bolt / nut 10 is optimal in terms of strength, construction method, and cost.

Effect of the invention

As described above, the seismic isolation device of the present invention is effective for horizontal shaking of an earthquake.
Moreover, since the device configuration is simple and clear, the operation is highly reliable and can be manufactured at low cost.

wrap up

In order to protect the structure from strong ground motion during a large earthquake, various seismic isolation devices have been put between the ground and the structure so that the vibration of the ground is not transmitted directly. The present invention relates to a rolling seismic isolation device that is considered to be able to provide the lowest horizontal resistance force among these seismic isolation devices.
The seismic isolation device of the present invention is a flat steel plate, a main steel ball placed in a rotatable state on the plane, and the main steel ball is held in a fixed positional relationship on the same plane, and all steel Two or more pairs of small-diameter steel balls that hold the balls in a rotatable state reduce the rolling resistance of the main steel balls by surrounding the main steel balls, thereby transmitting the horizontal vibration due to the earthquake to the structure. There is no seismic isolation device. Further, since the number of small-diameter steel balls is large, the load on the structure applied to one small-diameter steel ball can be reduced, and the durability of the seismic isolation device can be improved and the main steel balls can be smoothly rotated.

  FIG. 1 is a sectional view and FIG.   Explanatory drawing of seismic isolation operation | movement of this invention (a) is a case where the earthquake shake is from right to left, (b) is a case where the earthquake shake is from left to right.   It is a figure showing the basic component of this invention seismic isolation apparatus.   It is an example of the fixing method of the steel plate 6 and the foundation 8 of a building.

1: Main steel ball 2: First small-diameter steel ball group 3: Second small-diameter steel ball group 4: Upper member 5: Lower member 6: Steel plate 7: Screw 8: Building foundation 9: Building foundation structural material 10 : Screws for fixing steel plates

Claims (1)

  A flat steel plate, a main steel ball placed in a rotatable state on the flat steel plate arranged under the flat steel plate, and the main steel balls are held in a fixed positional relationship on the same plane, and all the steel balls A seismic isolation device comprising a group of steel balls held by a position holding retainer that holds the wheel in a rotatable state and covers at least two or more groups of the main steel balls in a rotatable state.

Images