JPH05332008A - Base isolation device - Google Patents

Abstract

PURPOSE:To provide base isolating performance and ability to return to an original position in a rolling support, and also provide proper damping performance while avoiding an operation time resonance. CONSTITUTION:A base isolation device is composed of a support body 1 which is fixed to a lower structure and whose upper surface 1a is in a curved shape and a rolling support 2 connected to an upper structure so as to support vertical load while rolling on the support body 1. By constituting in such a way that the upper surface 1a of the support body 1 can have a large curvature in the central part where the rolling support 2 is situated at a normal time and can have an outer peripheral part curvature smaller than that of the central part and can have two or more downward projecting curvatures, a base isolating performance and an ability to return to its original position can be provided in the rolling support 2 while avoiding an operation time resonance. Viscous fluid 3 is stored on the upper surface 1a of the support body 1, and a resistance plate 22 is installed under the rolling support 2, so that a proper viscosity attenuating performance can be also provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic isolation device mainly used for floor seismic isolation.

[0002]

The bearings of seismic isolation devices used for floor seismic isolation are roughly classified into sliding bearings that are fixed to the floor that is the upper structure and slide on the lower structure, and rolling bearings that roll. However, rolling bearings with a small friction coefficient are advantageous and have many practical examples in order to exert the insulating effect from the low-level vibration of the substructure.

The rolling bearing is mounted on a bearing fixed to the lower structure and moves in two horizontal directions.
Since the upper surface of the conventional bearing is usually composed of a flat surface or a curved surface having a certain curvature, the rolling bearing has a fixed cycle, which may cause resonance with the lower structure.

When the upper surface of the support is curved,
In order to increase the seismic isolation performance of rolling bearings, the curvature of the curved surface becomes smaller in order to increase the period, and the return force to the original position decreases. There is a problem of falling.

The present invention has been made by paying attention to the problem of the bearing of the rolling bearing type seismic isolation device, and is intended to newly propose a seismic isolation device that solves the above problem.

[0006]

According to the present invention, the upper surface of the support for supporting the rolling bearing is formed of a curved surface having two or more downwardly convex curvatures while avoiding resonance with the lower structure during operation. , Rolling bearings should have seismic isolation and return to original position.

The upper surface of the bearing has a curved surface with a large curvature at the central portion where the rolling bearing is normally positioned and a small curvature at the outer peripheral portion, and the periodic characteristic of the rolling bearing becomes non-linear due to the change in curvature, resulting in resonance. Is avoided.

The original position return ability when the rolling bearing moves relative to the bearing is secured by the central portion having a large curvature, and the seismic isolation performance is exhibited at the outer peripheral portion having a small curvature.

At the same time that the viscous fluid is stored on the support, a resistance plate is installed on the viscous fluid side of the rolling support, and the resistance plate is immersed in the viscous fluid to obtain a damping force when the rolling support moves. Since the distance between the resistance plate and the bearing is kept constant by the rolling bearing, the damping performance is also kept constant.

Further, a vertical spring for insulating the vertical vibration of the lower structure is arranged between the upper structure and the rolling bearings, and a rod for reaching the viscous fluid is projected on the upper structure side so that the vertical structure can be relatively moved. The damping force is secured.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing an embodiment.

The seismic isolation apparatus A of the present invention is fixed to a lower structure, and has a support 1 having a curved upper surface 1a and a support 1 connected to an upper structure, and rolling on the support 1 to support a vertical load. It is composed of the bearing 2 and is installed mainly between the floor slab which is the lower structure and the floor surface which is the upper structure, and performs the seismic isolation of the floor while avoiding the resonance during relative movement of the upper structure and the lower structure. Is.

[0013] body of the rolling bearing 2 is connected to a frame F that supports the load on the superstructure to rotate in any direction while being in contact with the scaffold 1 at its lower end, a plurality of ball bearings 2 _1, or thick The structure is such that one ball bearing with a diameter is stored.

As shown in FIG. 1, the upper surface 1a of the support 1 has two or more downwardly convex curvatures, the rolling support 2 has a large central portion where the rolling bearing 2 is normally located, and the outer peripheral portion has a large curvature. It is getting smaller. FIG. 2 shows the plane of FIG.

FIG. 3 shows a periodic characteristic corresponding to the relative position of the rolling bearing 2 with respect to the curved support body 1 shown in FIG. 1. The lower structure from the normal state at the center of FIG. When a relative movement occurs with respect to the upper structure, the vibration period of the rolling bearing 2 is short within the range of movement of the central portion having a large curvature, and the original force restoring force of the rolling bearing 2 is high within this range. .. The movement amount over the range of the outer peripheral portion deviating from the central portion has a longer cycle, and the greater the relative movement amount, the more the seismic isolation effect of the rolling bearing 2 increases. When the amount of movement is large, the vibration cycle changes due to the difference in curvature between the central portion and the outer peripheral portion, and resonance with the input from the lower structure is avoided.

In the illustrated embodiment, when the rolling bearing 2 causes an excessive relative movement with respect to the bearing body 1, it is stopped and at the same time, the rolling bearing 2 is located closest to the outer periphery in order to give a restoring force to the original position. The curvature of the part is increased.

Damping when the rolling bearing 2 moves relative to each other is obtained by viscous fluid 3 stored on the bearing 1 as shown in the figure.

[0018] In the viscous fluid 3, rolling is installed on ball bearing 2 ₁ of the support 2 resistance sheet 2 ₂ immersed, rolling principally resistive plate movement of the support 2 during relative movement of the bearing body 1
Is attenuated by shear resistance force generated 2 ₂ of the lower surface.

[0019] While the vibration in the vertical direction between the lower structure and the upper structure is interrupted by a vertical spring 2 ₃ which are arranged vertically oriented shaft on the body of the support 2 rolling, the attenuation during vertical vibration underside of the superstructure It is ensured by projecting the rod 2 ₄ reaching the viscous fluid 3 from. The effect of attenuation will form a rod 2 ₄ into a plurality of cylinders and wall plate can be adjusted by changing the area immersed in the viscous fluid 3.

[0020]

The present invention is as described above, and since the upper surface of the supporting body for supporting the rolling bearing is constituted by a curved surface having two or more curvatures convex downward, the boundary where the curvature changes is sandwiched. Since the rolling bearing has a non-linear cycle, resonance with the lower structure during operation can be avoided, and at the same time, the curvature of the rolling bearing in the normal position is large, so that the rolling bearing moves to the original position after moving. It can have a return ability.

Further, at the same time as storing the viscous fluid on the support, a resistance plate or rod is installed on the viscous fluid side of the rolling support, and by immersing them in the viscous fluid, the rolling support moves or moves during vertical vibration. Vibration can be damped. This viscous fluid also has the effect of lubricating the rolling bearing and preventing rust.

In addition, since the seismic isolation device and the damper are realized by a single device by combining the rolling bearing and the viscous fluid as the damper, the mechanism required for the seismic isolation is simplified and at the same time, the manufacturing cost is reduced. Reduction is achieved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a seismic isolation device.

FIG. 2 is a plan view of FIG.

FIG. 3 is a periodic characteristic diagram corresponding to a curvature of a support body of the rolling support of FIG.

[Explanation of symbols]

A: seismic isolation device, 1 ... support, 1a ... top surface, 2 ... rolling support, 2 ₁ ... ball bearing, 2 ₂ ... resistance plate, 2 ₃
…… Vertical spring, 2 ₄ …… Rod, 3 …… Viscous fluid, F ……
flame.

Claims (3)

[Claims] 1. A support body which is fixed to a lower structure and has a curved upper surface, and a rolling support which is connected to the upper structure and supports a vertical load while rolling on the support body. The seismic isolation device is characterized in that the upper surface has two or more curvatures that are convex downwards, the rolling bearing has a large curvature at the central portion where it is normally located, and the outer peripheral portion has a smaller curvature than the central portion. 2. A viscous fluid is stored on the support, a resistance plate is installed on the viscous fluid side of the rolling support, and the resistance plate is immersed in the viscous fluid. Seismic isolation device. 3. A vertical spring whose axis is oriented vertically is arranged between the upper structure and the rolling bearing, and a rod reaching the viscous fluid is projectingly provided on the upper structure side. The seismic isolation device according to item 2.