JPH09170355A - Base isolator for detached house - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a trigger function freely settable by providing a sliding member which is designed to vibrate freely in the horizontal direction when a force acts in the horizontal direction if the force exceeds a specified magnitude, and a trigger member. SOLUTION: This base is dates is provided with a sliding member (ball bearing) 19 which supports a detached house and slides freely in the horizontal direction if a force over an arbitrary and definite magnitude acts in the horizontal direction and attenuates its vibration and a trigger member (preliminarily tensile spring) 20 provided with a pair of cylinders inside a coil spring. A rigid steel plate 2 and the ball; bearing 19 are laid out on a foundation where a preliminary extension spring 20 is laid out between each ball bearing 19. The preliminary extension spring 20 is mounted between a mounting area 24 on the foundation side and a mounting area 25 on a house side. The preliminary extension springs are laid out for their orientation in such a fashion that at least the paired preliminary extension springs may be opposed to each other. This construction makes it possible to set a trigger function freely based on a rocking attenuation action by friction force a preliminary tensile force of the extension spring.

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 for a structure, and more particularly to a detached seismic isolation device which does not operate with a small seismic force but performs an appropriate damping action when it swings with a large seismic force. .

[0002]

2. Description of the Related Art Conventionally, a building seismic isolation device that has been widely used is composed of a multi-layer laminated rubber and a steel damper. This laminated rubber is a support member for a building and operates as a horizontal restoring force. Steel dampers act as vibration dampers,
Oil dampers, viscous dampers, lead dampers,
A friction damper or the like is used. In this type of seismic isolation device, the rigidity is higher than that of a metal spring due to the material characteristics and structural characteristics of the laminated rubber. As a result, the frequency of the seismic wave becomes very short, which is close to a short period, and the seismic isolation effect is not very good. Furthermore, there is no trigger (starting force setting) provided for a cause of vibration that always acts, such as a strong wind, so that there is a problem that the building swings and the livability deteriorates.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a seismic isolation device for a detached house in which a trigger function can be freely set by damping due to frictional force and pre-tensioning force of a tension spring.

[0004]

Means for Solving the Problems The structure of the present invention for solving the above problems is a seismic isolation device as described below. (1) Supports a detached house, and when a horizontal seismic force exceeding a certain magnitude acts, the seismic force transmitted to the detached house is attenuated, and it is possible to return to the origin after rocking due to an earthquake A detached house seismic isolation device including a sliding member and a trigger member. (2) The detached seismic isolation apparatus according to (1), wherein the sliding member is arranged in a ball bearing group for freely swinging in the horizontal direction and has a spring for pressing the friction material. (3) The detached seismic isolation apparatus according to (1) or (2), wherein the trigger member is a pre-tension spring having a pair of cylinders inside a coil spring.

That is, the present invention relates to a seismic isolation device including the ball bearing shown in FIG. 1 and the pre-tension spring shown in FIG. This is a seismic isolation device whose cycle can be set at values far apart, and consists of the following devices. (1) A ball bearing that supports a structure and can move freely on the plane of a rigid steel plate by an arbitrary constant force in the horizontal direction (FIG. 1). (2) A metal pre-tension coil spring (FIG. 2) that can be set to a longer cycle than seismic waves.

[0006]

By having the above-mentioned devices (1) and (2), for example, the mechanism for preventing the house from swinging (trigger function) due to strong wind can be reduced by the frictional force of the friction material provided in the ball bearing shown in FIG. The pretensioning force of the pretensioning coil spring can be freely set by changing the pretensioning length of the spring and the rigidity of the elastic body serving as a pressing member for the friction material. The friction material provided in the ball bearing acts as a damping material during vibration such as an earthquake.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the drawings. FIG. 1 is a partially cutaway side view for explaining an example of a bearing used in the apparatus of the present invention. This bearing is mounted on a pedestal 2 on a bearing ball 1 on a rigid steel plate 2.
The base 22 can freely move in the horizontal direction because the base 2 is mounted. However, the friction member 5 is pressed against the hard steel plate 2 by the pressing member 3 via the disc spring 4 at the center of the pedestal 22. The pedestal 22 and the entire bearing ball 1 are housed in a cover 23, and the pressing member 3 protrudes slightly upward from the cover 23. When the base of the house is placed, the pressing member 3 descends and the disc spring 4 The frictional material 5 is pressed against the hard steel plate 2 via. Thus, the frictional force between the friction material 5 and the hard steel plate 2 acts to suppress the movement of the pedestal 22 to some extent. Therefore, when the force acting on the pedestal is small, there is no seismic isolation effect, and when the size exceeds a certain limit, the seismic isolation effect is exerted. In this case, the frictional force between the friction material 1 and the hard steel plate 2 suppresses the swing of the pedestal, and can prevent the swing from continuing for a long time.

FIG. 2 shows a pretension coil spring which is one of the trigger members used in the present invention. 2A shows a state where the coil spring is expanded, FIG. 2B shows a state where the coil spring is attached to a foundation of a building, and FIG. 2C shows a state where the coil spring is most contracted. This pre-tension spring has an outer cylinder 6 and an inner cylinder 7 at the center,
Is provided with a hook 9 having a spherical bearing 14 at one end, and a head 18 large enough to enter the inside of the outer cylinder 6 is provided at one end of the inner cylinder 7. The rod 10 has a stopper 1
1, the disc spring 12 and the hook 13 are slidably fitted to each other, and the stopper 11 is pressed by the hook 13 through the disc spring 12 toward the end of the outer cylinder.
The other end of the rod 10 has a hook 15 and a spherical bearing 16.

A tension spring 8 is provided between a hook 9 provided at one end of the outer cylinder 6 and a hook 13 slidably fitted to the rod 10, and is adjusted to give an appropriate pretension force. Have been. An extendable cover 17 is provided between the hook 9 and the hook 15, and covers the entire extension spring. The operation of the pre-tension spring will be described. In the normal state, the end of the head 18 provided at one end of the cylinder and the end of the outer cylinder 6 are in contact with the stopper 11, as shown in FIG. . As shown in FIG. 2A, the state where the pre-tension spring is extended after the swinging of the building has started is the head 1 of the inner cylinder 7.
8 pushes the hook 13 through the stopper 11 and the disc spring 12, so that the tension spring 8 having one end fixed to the hook 13 is extended. As a result, the force of contraction of the tension spring 8 acts as a restoring force (trigger function) in the direction of contracting the spherical bearing 16 via the head 18 and the rod 10 at one end of the inner cylinder 7. When the pre-tension spring is contracted from the normal state, the inner cylinder 7 is immersed in the outer cylinder 6 as shown in FIG. You will be immersed in In this state, the stopper 11 remains at the end of the outer cylinder 6, so that no force acts on the head 18 of the inner cylinder 7, and therefore no force acts on the spherical bearing 16 at the end of the rod 10. Does not work.

FIGS. 3 and 4 show an example in which the bearing shown in FIG. 1 and the pre-tension spring shown in FIG. 2 are attached to an actual building. FIG. 3 is an explanatory plan view showing an example of mounting the rigid steel plate 2, the ball bearing 19, and the pre-tension spring 20 on a foundation, and FIG. 4 is an explanatory diagram of a side surface thereof. A hard steel plate 2 and a ball bearing 19 are arranged on a foundation, and a pre-tension spring 20 is arranged between the ball bearings 19. The pre-tension spring 20 is mounted between the mounting portion 24 on the base side and the mounting portion 25 on the house side. The orientation of the pre-tension springs 20 can be properly exerted by the seismic isolation function (trigger function) of the building by arranging at least one pair of pre-tension springs 20 in one direction so as to face each other.

[0011]

Hereinafter, the results of one-mass-system response calculation for seismic waves observed in the past using the seismic isolation device of the present invention will be described with reference to examples. However, the input maximum speed was set to 50 cm / s.

[0012]

[Table 1]

[0013] The above results show that the width is 30 cm and the height of the center of gravity is 150.
This shows that the response acceleration can be suppressed to about 80% of that of the fall start acceleration of furniture and the like of about 100 Gal, which is about 100 Gal. The above calculation results show that when the weight of the structure (building) is about 40 tons, the acceleration corresponding to the pre-tension force of the pre-tension spring shown in FIG. 2 is 45 Gal, and the friction material 5 provided inside FIG. The acceleration is 35 Gal corresponding to the frictional force with the steel plate 2, and a total of 80 Gal is set as a braking function (trigger function) against a strong wind.
Changing the pretension length of the tension spring 8 in FIG.
The braking force can be freely adjusted by changing the pressing force of the friction material 5 by changing the rigidity of the pressing material 3 and the disc spring 4 in FIG.

[0014]

As described above, the detached seismic isolation device of the present invention has a braking function, and the braking function can be arbitrarily set by adjusting the disc spring or the pre-tension spring of the ball bearing. .

[Brief description of the drawings]

FIG. 1 is a partially cutaway explanatory view of an example of a bearing used in the present invention.

FIG. 2 shows a specific example of a pre-tension spring used in the present invention, when a is extended, b is attached, and c is contracted.

FIG. 3 is an explanatory view showing an example of a planar arrangement of the detached seismic isolation device of the present invention.

FIG. 4 is an explanatory diagram showing a side view of the arrangement of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bearing ball 2 Rigid steel plate 3 Pressing material 4 Elastic body such as disc spring or compression coil spring 5 Friction material 6 Outer cylinder 7 Inner cylinder 8 Tension spring 9 Hook 10 Rod 11 Stopper 12 Belleville spring 13 Hook 14 Spherical bearing 15 Hook 16 Spherical bearing 17 Cover 18 Head 19 Ball bearing 20 Pre-tension spring 21 Base-isolated detached base 22 Pedestal 23 Cover 24 Mounting part of pre-tension spring on base side 25 Mounting part of pre-tension spring on house side

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuyuki Sone 1-9-31 Shinonome, Koto-ku, Tokyo Inside the sound and vibration department of Mitsubishi Steel Corp. (72) Akira Matsuda 1-9-31 Shinonome, Koto-ku, Tokyo (72) Inventor, Daisuke Yaguchi 1-9-31 Shinonome, Koto-ku, Tokyo Mitsubishi Steel Mfg. Co., Ltd.

Claims (3)

[Claims] 1. When a seismic force that supports a detached house and horizontally exceeds a certain fixed level acts on the detached house, the seismic force transmitted to the detached house is attenuated, and the origin is restored after rocking due to an earthquake. A detached seismic isolation device comprising a sliding member and a trigger member that can be used. 2. The detached house according to claim 1, wherein the sliding member has a spring arranged in a group of ball bearings for freely swinging in a horizontal direction and for pressing a friction material. Seismic isolation device. 3. The detached seismic isolation device according to claim 1, wherein the trigger member is a pre-tension spring having a pair of cylinders inside a coil spring.