JPH1144125A - Base isolation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispersively support a load of a structure, improve stability, and easily perform execution work by arranging plural string-like elastic members at equal intervals between an outer peripheral part of a receiving plate and an outer peripheral part of a ball bearing, and positioning the receiving plate and the ball bearing in a concentric shape before a support plate is placed on the ball bearing. SOLUTION: A receiving plate 1 composed of a circular steel plate is fixed on a footing B through an intermediate plate 2 by forming an upper surface 1a of a part to place a ball bearing 5 as a conical recessed part. A support plate 3 composed of a circular steel plate is fixed under a structure S through an intermediate plate 4 by forming an under surface 3a on the side opposed to the upper surface 1a of the receiving plate 1 as a conical projecting part. A ball bearing 5 where plural steel balls 5b, 5b... are arranged at prescribed intervals in a circular ring-shaped ball holder 5a, is arranged between the receiving plate 1 and a support plate 3, and coil springs 7a to 7d being an elastic member are arranged at equal intervals between a side wall 6 and an outer periphery of the ball bearing 5, and before the support plate 3 is placed on the ball bearing 5, the receiving plate 3 and the ball bearing 5 are positioned in a concentric shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a seismic isolation device,
In particular, it relates to a seismic isolation device using a rolling bearing.

[0002]

2. Description of the Related Art Conventionally, a seismic isolation device using a rolling bearing of this type has a vibration ground and an object such as a building structure or a sculpture installed on the vibration ground (hereinafter referred to as a "structure"). In order to insulate the rolling members from each other, it is devised to minimize the friction of the rolling surface.

For example, in a seismic isolation device disclosed in Japanese Patent Publication No. Hei 6-35769, a large number of ball bearings are provided on a tray on the foundation side, and a bearing body for supporting a structure is placed on the ball bearings. It is configured as follows. Also,
In the seismic isolation device disclosed in Japanese Patent Publication No. 5-14062, one large-diameter steel ball is placed on a pan on the foundation side, and a large number of small-diameter steel balls are placed on the upper surface of the large-diameter steel ball. A sphere is provided to support the structure.

The above-described seismic isolation device using a ball bearing or a steel ball has a feature that the friction coefficient, that is, μ, can be extremely reduced, and has a characteristic that it is smaller than a rubber bearing formed by laminating rubber plates. Can withstand high loads,
In addition, it has the feature of low cost.

However, in this conventional seismic isolation device of a rolling bearing in which a large number of ball bearings are provided on a tray, there is a concern that when the ball bearings on the tray receive contact, friction increases. 1 steel ball of diameter
In the case of the seismic isolation device used individually, the load of the structure is concentrated on one point of the pan, so that there is a problem that the material of the pan must be a special material having high strength.

Further, a seismic isolation device using a rolling bearing such as a ball bearing is inferior in resilience. Therefore, it is used in combination with a rubber bearing having a high resilience effect or in combination with a resilience mechanism such as a hydraulic damper. There was a disadvantage that it had to be done.

Therefore, the applicant of the present application has previously filed Japanese Patent Application No. 9-1.
No. 47441 and Japanese Patent Application No. 9-147443,
Provided is a seismic isolation device using a ball bearing that can support the structure by dispersing the load of the structure without fear of contact between steel balls, and also provides an upper surface of a receiving plate provided on the foundation side and a structure. The lower surfaces of the supporting plates supporting the fins are formed in conical concave portions, respectively, to provide a seismic isolation device having excellent restoring properties.

[0008]

The seismic isolation device according to the above proposal is characterized in that it can prevent the steel balls from coming into contact with each other, support the structure in a distributed manner, and have excellent resilience. However, there has been a problem that the receiving plate and the ball bearing are separate parts, which is inconvenient to construct, and a seismic isolation device having more excellent restorability has been desired.

Therefore, the present invention solves the above problems,
It was made in response to the above request,
An object of the present invention is to provide a seismic isolation device in which a receiving plate and a ball bearing are integrated, and which has excellent resilience.

[0010]

In order to achieve the above object, a seismic isolation device according to the present invention is provided on a receiving plate provided on a base side having an upper surface formed in a conical or spherical concave portion. A structure in which a ball bearing formed by arranging a plurality of steel balls at a distance from each other via a ball holder is provided, and a lower surface is formed on the ball bearing with a conical convex portion or a spherical convex portion. A seismic isolation device in which a support plate for supporting the ball bearing is movably mounted in a horizontal direction, wherein the ball bearing comprises a plurality of ball bearings disposed at equal intervals between an outer peripheral portion of the receiving plate and an outer peripheral portion of the ball bearing. A string-shaped elastic member is provided, and before the support plate is placed on the ball bearing, the receiving plate and the ball bearing are concentrically positioned.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing a left half of a seismic isolation device according to an embodiment in cross section, and FIG.
FIG. 4 is a cross-sectional view taken along a line A.

The receiving plate 1 is made of a circular steel plate, and an upper surface 1a of a portion on which a ball bearing 5 to be described later is mounted has a horizontal shape.
Further, it is formed in a conical concave portion, and is provided on the foundation B via the intermediate plate 2. Although not shown, the receiving plate 1 and the intermediate plate 2 are connected to the base B via anchor bolts.
It is fixed to. Further, the upper surface 1a of the receiving plate 1 may be a spherical recess instead of a conical recess.

The supporting plate 3 is made of a circular steel plate similarly to the receiving plate 1, and the lower surface 3a of the receiving plate 1 on the side facing the upper surface 1a is horizontal and has a conical convex shape that is convex downward. And is provided below the structure S via the intermediate plate 4. Although not shown, the support plate 3 and the intermediate plate 4 are fixed to the structure S by fixing tools such as bolts and nuts. Further, the lower surface 3a of the support plate 3 may be a spherical convex instead of a conical convex.

The ball bearing 5 has the same structure as a well-known thrust load ball bearing, and is available as a commercial product.
A plurality of steel balls 5b are provided at a predetermined interval in a circular ring-shaped ball holder 5a. And
The ball bearing 5 is disposed between the upper surface 1a of the receiving plate 1 and the lower surface 3a of the supporting plate 3, and combines the receiving plate 1 and the supporting plate 3 into a rolling bearing.

In FIG. 1, reference numeral 6 denotes a side wall fixedly and integrally provided around the receiving plate 1, the upper end of which is provided so as to protrude from the upper surface of the receiving plate 1. In addition,
The height of the upper end of the side wall 6 is determined so that the support plate 3 does not contact the side wall 6 even when the support plate 3 moves horizontally.

The coil springs 7a to 7d correspond to the string-shaped elastic member of the present invention, and are provided at equal intervals between the side wall 6 and the outer periphery of the ball bearing 5, that is, the outer periphery of the ball holder 5a. The springs 7a to 7d have the same strength. Therefore, the ball bearing 5 can be positioned concentrically with the receiving plate 1 and can be integrated with the receiving plate 1. Here, the coil spring 7
Although one end of each of a to 7d is provided inside the side wall 6, the side wall 6 may be omitted and the end may be directly attached to the outer peripheral portion of the receiving plate 1.

Here, the four coil springs 7a to 7a
Although 7d is provided, three or five or more coil springs may be provided at equal intervals. But three or four
Even with a small number of coil springs, the ball bearings 5 can be positioned concentrically with respect to the receiving plate 1 and the required resilience can be obtained. Furthermore, these coil springs can be made of string-like tough rubber.

In the seismic isolation device having the above structure, the load of the structure S can be supported by a large number of steel balls, so that the load can be prevented from being concentrated on one point of the receiving plate 1 and the supporting plate 3.
In addition, the material of the support plate 3 can be easily selected.
Also, since the steel balls 5b of the ball bearing 5 are held by the ball holder 5a, the contact between the steel balls can be effectively prevented. Moreover, before the ball bearing 5 is integrated with the receiving plate 1 and the support plate 3 is mounted on the ball bearing 5,
Since the ball bearing 5 is positioned concentrically with respect to the receiving plate 1, construction can be performed easily.

Further, in the seismic isolation device having the above structure, the ball bearing 5 has the conical concave portion on the upper surface 1 a of the receiving plate 1 and the lower surface 3 of the supporting plate 3.
Since it is intended to be located at the most depressed position of the conical convex portion of a, since it further has coil springs 7a to 7d,
Even when the structure moves due to an earthquake or the like, it is possible to obtain the resilience of returning to the original position. In addition, the upper surface 1a has a spherical concave portion,
The same effect is obtained when the lower surface 3a is formed as a spherical convex portion.

Further, since the ball bearing is located at the most concave position of the conical concave portion or spherical concave portion on the upper surface of the receiving plate and the conical convex portion or convex spherical portion of the lower surface of the support plate,
Further, since the coil spring is provided, even when the structure moves due to an earthquake or the like, it is possible to obtain resilience for returning the structure to its original position. The same effect can be obtained by using a string-shaped rubber instead of the coil spring.

A solid lubricant made of molybdenum disulfide or the like is adhered between the upper surface 1a of the receiving plate 1 and the lower surface 3a of the support plate 3, and between the steel ball 5b and the ball holder 5a, so that the movement of the steel ball 5b is controlled. Also, the movement between the steel ball 5a and the ball holder 5b may be made good.

Although not shown, between the receiving plate 1 and the foundation B or between the supporting plate 3 and the structure S, a coil spring,
A vibration isolator such as a laminated rubber or an air spring may be provided to block vertical vibration.

[0023]

According to the ball bearing of the seismic isolation device of the present invention, a plurality of cord-like elastic members are provided at equal intervals between the outer peripheral portion of the receiving plate and the outer peripheral portion of the ball bearing. Before the supporting plate is placed on the bearing plate, the receiving plate and the ball bearing are positioned concentrically, so that the load of the structure can be supported by a large number of steel balls, and the receiving plate and the supporting member can be supported. Concentration of the load on one point of the plate can be prevented. For this reason, selection of the material of a receiving plate and a support plate can be performed easily. Further, since each steel ball of the ball bearing is held by the ball holder, contact between the steel balls can be effectively prevented. Moreover,
Before the ball bearing is integrated with the receiving plate and the support plate is placed on the ball bearing, the ball bearing is concentrically positioned with respect to the receiving plate, so that the work can be easily performed.

[Brief description of the drawings]

FIG. 1 is a front view showing a left half of a seismic isolation device according to an embodiment of the present invention in cross section.

FIG. 2 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Receiving plate 1a Upper surface 2, 4 Intermediate plate 3 Support plate 3a Lower surface 5 Ball bearing 5a Ball holder 5b Steel ball 6 Side wall 7a-7d Coil spring (string-like elastic member)

Claims (1)

[Claims] 1. A plurality of steel balls are formed at intervals from each other via a ball holder on a receiving plate provided on a base side having an upper surface formed in a conical concave portion or a spherical concave portion. A seismic isolation device comprising a ball bearing, and a support plate, which supports a structure having a conical convex portion or a spherical convex portion on the lower surface, movably mounted in a horizontal direction on the ball bearing. In the ball bearing, a plurality of cord-like elastic members are provided at equal intervals between the outer peripheral portion of the receiving plate and the outer peripheral portion of the ball bearing, and the support plate is mounted on the ball bearing. A seismic isolation device characterized in that the receiving plate and the ball bearing are positioned concentrically before.