JPH09195570A - Vibration isolation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device which can suppress a vertical supporting force of which a laminated rubber takes charge even when a large earthquake has arisen and hence, which does not require to install a laminated rubber isolator with a large supporting area because of previous expectation of a large deformation and prevents a resonance with an earthquake. SOLUTION: This device is provided with a pair of lower plate 30 and intermediate plate 31 vertically facing each other, steel plates 32, 32 arranged between the lower plate 30 and the intermediate plate 31, and rubber pieces 33, 33 alternately laminated between the plates 32 at the four corners. A vertical cylindrical columnar body 37 for supporting the vertical load is fixed under the center of the intermediate plate 31. A low frictional block 39 is fixed at the front end of the lower part of the columnar body 37. The lower end face of the low frictional block 39 is positioned to face the upper face of the lower plate 30 with a clearance. The clearance therebetween is so little that both faces get into contact with each other when the distance between the lower plate and the intermediate plate becomes small at a large earthquake. The upper face of the lower plate 30 is machined to form a mirror face and the low frictional block 39 slides smoothly on the upper face of the lower plate 30, when a large earthquake has arisen.

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 used for a structure, particularly an office building, an apartment house, a general house or the like.

[0002]

2. Description of the Related Art Conventionally, various developments have been made as seismic isolation devices for suppressing shaking of various structures due to an earthquake.
Some have been put to practical use. As this type of seismic isolation device, a laminated rubber isolator is generally formed by alternately laminating a rubber plate and a steel plate between a pair of plates in a sandwich shape. Such a laminated rubber isolator is interposed between the foundation and the structure to be seismically isolated, vertically supporting the load of the superstructure and acting as a soft spring in the horizontal direction, and the seismic input energy as elastic strain energy. It absorbs.

[0003]

However, in the conventional laminated rubber isolator, the laminated rubber isolators are largely deformed in the event of a large earthquake, and along with this deformation, all laminated rubbers (steel plates) are projected in a plane. As a result of the smaller overlapping area, the vertical supporting force becomes smaller than that in the case of having a large overlapping area before deformation. In this way, when a large earthquake occurs, it deforms significantly and the vertical support force decreases.Therefore, it is necessary to install a laminated rubber isolator with a large support area in advance in order to secure the vertical support load obtained by design even after the deformation. is there. If the area of the laminated rubber is increased, the natural frequency of the structure to be seismically isolated correspondingly increases.By avoiding this by lowering the natural frequency of the structure below the frequency band of the seismic waveform, resonance with the earthquake occurs. It becomes difficult not to do so, and it is disadvantageous for cost reduction.

Therefore, the present invention provides a laminated rubber isolator which can suppress the vertical supporting force of the laminated rubber even in the event of a large earthquake, and which has a large supporting area in anticipation of large deformation. It is an object of the present invention to provide a seismic isolation device that does not need to be installed and is less likely to resonate with an earthquake.

[0005]

In order to achieve the above object, the invention according to claim 1 vertically faces a plurality of laminated rubbers in which rubber plates and steel plates are alternately laminated in a sandwich shape. Placed between a pair of plates,
A vertical load-supporting column is fixedly hung from the lower part of the plate located above, and the lower end of the column is a low friction part capable of sliding contact with the upper surface of the plate located below, It is characterized in that the upper surface of the plate located below is mirror-finished.

According to a second aspect of the present invention, the laminated rubber is arranged around the column.

The invention according to claim 3 is characterized in that an air spring for suppressing vibration in the vertical direction is integrally provided on the upper part of the plate located above.

According to a fourth aspect of the present invention, the air tank portion of the air spring is embedded in the seismic isolation target.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention basically arranges a plurality of laminated rubbers obtained by alternately laminating rubber plates and steel plates in a sandwich shape between a pair of plates facing each other in the vertical direction, and A vertical load supporting column is fixedly hung from the lower part of the plate located above, and the lower end of the column is a low-friction part capable of sliding contact with the upper surface of the plate located below. Since the upper surface of the plate located at is mirror-finished, the laminated rubber deforms horizontally as a soft spring to absorb the input energy as elastic strain energy during an earthquake.

When a large earthquake occurs, a pair of plates (laminated rubber) undergo a large relative deformation in the horizontal direction, and even if the overlapping area in which all the laminated rubbers are projected in a plane becomes small due to this deformation. The large load of the structure is supported by the column. The low friction portion of the column smoothly slides on the upper surface of the lower plate as the plate horizontally moves. At this time, the value obtained by multiplying the vertical load and the friction coefficient becomes the sliding resistance between the column and the lower plate, and this sliding resistance suppresses excessive horizontal deformation.

A small gap exists between the low-friction portion of the column and the plate located below it so that they can contact each other when the distance between the upper and lower plates becomes small due to a large earthquake. Preferably.

The low-friction portion can be formed by embedding a block made of a low-friction material such as Teflon at the lower end of the column. In this case, the columnar body can be formed in a hollow shape, and the low friction block can be screwed to the columnar body.

The laminated rubber is preferably arranged around the column body. For example, the laminated rubber can be arranged at four corners of a rectangular plate, and the column body can be arranged at the center thereof.

An air spring for suppressing vertical vibration can be integrally provided on the upper portion of the plate located above. In this case, the air tank portion of the air spring is preferably embedded in the seismic isolation target. Further, the air spring may be replaced with a metal spring.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment in which the present invention is applied to a seismic isolation device for a clean room will be described in detail with reference to the accompanying drawings. 1 is a sectional view showing an example of a clean room to which the present invention is applied, FIG. 2 is a sectional view of a seismic isolation apparatus according to the present invention, FIG. 3 is a sectional view taken along line III-III of FIG. 2, and FIG. FIG. 5 is a correlation diagram between the horizontal deformation of the laminated rubber and the supporting load carried by the laminated rubber and the column, and FIG. 6 is a sectional view showing another embodiment.

In the clean room 1, the air flowing down from the ceiling is passed through the floor surface to the retan chamber 5 under the floor. The main pillar 7, on the floor of the return chamber 5,
7 are erected, large beams 9 and 9 are installed in parallel between the main columns 7 and 7, and small beams 11 and 11 are large beams 9 and 9 between the large beams 9 and 9.
A plurality of joists 13 and 13 are erected on the lattice constituted by the large beams 9 and 9 and the small beams 11 and 11 in parallel with each other in an appropriate pitch in a direction orthogonal to. The gratings 15, 15 are placed on the joists 13, 13 to form the floor surface of the clean room 1.

In the retan chamber 5, a pillar 1 is installed on the floor surface of the chamber 5 upright with the same span as the main pillars 7, 7.
A mount 19 supported by 7, 17 is provided. A relatively large waffle slab 23 is supported on the pedestal 19 via a plurality of seismic isolation devices 21 and 21. As is well known, the waffle slab 23 is a lattice-shaped slab constructed by RC construction or the like.

On a part of the floor of the clean room 1, the beam 11, the joist 13 and the grating 15 are removed to form an opening 25. On the other hand, a seismic isolation mount 27 is placed on the waffle slab 23 through the floor surface opening 25 of the clean room 1. On the seismic isolation mount 27, an anti-vibration device 29 such as a precision instrument that dislikes vibration is installed. There is.

The seismic isolation device 21 in this embodiment is composed of a laminated rubber isolator 21A arranged below and having a horizontal seismic isolation function, and an air isolation device 21 disposed above is mainly provided with a vertical seismic isolation function. A two-layer structure including a spring 21B is arranged at an appropriate position between the pedestal 19 and the waffle slab 23, and the waffle slab 23 is a seismic isolation target. A damper 22 that suppresses vertical vibration is disposed between the seismic isolation devices 21.

As shown in FIGS. 2 and 3, the laminated rubber isolator 21A includes a pair of rectangular plates (lower plate 30 and intermediate plate 31) facing each other in the vertical direction, and a gap between the lower plate 30 and the intermediate plate 31 as appropriate. A plurality of hollow rectangular steel plates 32, 32 arranged at a pitch and relatively small diameter rubbers (laminated rubber) 33 alternately laminated in a sandwich shape between the steel plates 32, 32 at the four corners thereof. Three
When the seismic input is transmitted to the gantry 19 by fixing the lower plate 30 to the gantry 19, the laminated rubbers 33, 33 are mainly deformed in the horizontal direction as soft springs, and the input energy thereof is elastic. Absorb as strain energy.

A cylindrical column 37 for vertically supporting a vertical load is fixedly provided at the lower center of the intermediate plate 31. An inner thread is formed on the inner periphery of the column body 37, and a movable portion 38 that can move up and down is screwed to the inner thread. A concave portion 38a is formed at the lower end of the movable portion 38, and a handle 38b for adjustment is attached to the outer periphery thereof. Then, Teflon (registered trademark) is provided in the concave portion 38a of the movable portion 38.
A block (low-friction portion) 39 made of low-friction material such as
It faces the upper surface of 0 with a slight gap. The gap between the two is lower plate 30 when, for example, a large earthquake occurs.
And the handle 38b so that the contact between the intermediate plates 31 is small when the distance between the intermediate plates 31 is small.
It is adjusted by rotating. The lower plate 30 is made of stainless steel, and its upper surface is mirror-finished so that the low friction block 39 of the pillar 37 can smoothly slide on the upper surface of the lower plate 30 when a large earthquake occurs. .
A blade-shaped reinforcing rib 41 is provided between the intermediate plate 31 and the outer periphery of the upper portion of the pillar 37.

The air spring 21B is arranged between the upper plate 43 fixed to the bottom surface of the waffle slab 23 and the intermediate plate 31. The air spring 21B is an air tank (cylinder) 45 in which air of a predetermined pressure is sealed and a piston (not shown) movable in the vertical axis direction inside the tank.
It mainly absorbs seismic input in the vertical direction.

Further, the intermediate plate 31 and the upper plate 4
A pair of metal springs 47 are provided between the two.
Each metal spring 47 has two thin steel plates 47a, 47a.
By curving b in the plate thickness direction and fixing and tightly connecting the respective one end faces to each other, the other end faces face each other with a predetermined gap, and the other end faces face each other.
1 and the upper plate 43, respectively. The metal spring 47 having such a structure has high horizontal rigidity (hard) and low vertical rigidity (soft). By increasing the horizontal rigidity of the air spring 21B,
It is possible to obtain a good seismic isolation response without the natural period (especially the second natural period) with respect to the horizontal and vertical directions (frequency) resonating with the input wave component of the earthquake.

As shown in FIG. 4, the lengths of the metal springs 47 are orthogonal to each other with the pillar 37 as the center so that the seismic isolation device 21 has a high horizontal rigidity in all directions when viewed in plan. Are arranged as follows.

The embodiment of the present invention has the characteristics described above. The laminated rubber isolator 21A mainly absorbs the horizontal component of the earthquake, and the air spring 21B mainly absorbs the vertical component of the earthquake. When a large earthquake occurs, the laminated rubber 33, 33 is greatly deformed in the horizontal direction,
The large load of the waffle slab 23 (the base isolation stand 27, the vibration-damping device 29) is supported by the pillar 37 by the low friction block 39 slidingly contacting the lower plate 30 (soft landing). The low-friction block 39 of the column 37 smoothly slides on the upper surface of the lower plate 30 as the intermediate plate 31 and the lower plate 30 move horizontally relative to each other. At this time, a value obtained by multiplying the vertical load and the friction coefficient becomes a slip resistance between the column 37 and the lower plate 30, and this slip resistance suppresses an excessive horizontal deformation.

From the above, even if the laminated rubber isolator 21A is largely deformed in the event of a large earthquake, the vertical load is supported by the column 37. The correlation between the relative horizontal deformation of the lower plate 30 and the intermediate plate 31 at this time and the supporting load (illustrated by the broken line) carried by the laminated rubbers 33, 33 and the supporting load (illustrated by the solid line) carried by the pillar 37 is illustrated. 5 shows. As described above, even if the supporting load carried by the laminated rubbers 33, 33 is reduced, the column body 37 supports the corresponding load, so that it is not necessary to install a laminated rubber isolator having a large supporting area in advance, and the waffle is not required. It becomes easy to avoid the natural frequency of the seismic isolation structure such as the slab 23 by lowering it from the frequency band of the seismic waveform. Further, since the laminated rubber isolator having a large area is not used, the cost can be reduced.

Further, in this embodiment, the seismic isolation mount 27 on which the vibration-damping device 29 is placed is installed on the floor surface of the return chamber 5 via the vibration isolation devices 21 and 21. Vibration is suppressed. Micro vibrations generated when a worker passes over the gratings 15 and 15 propagate to other adjacent gratings through the joists 13 and 13. Since the slab 23 and the seismic isolation mount 27 are insulated, this slight vibration causes the waffle slab 23 and the seismic isolation mount 27.
Never propagate to.

FIG. 6 shows another embodiment. In this embodiment, the air tank 45 portion of the air spring 21B is embedded in the waffle slab 23. The air tank 45 part is supported by a supporting metal piece 49 having a hat-shaped cross section fitted in the opening 23 a of the waffle slab 23 instead of the above-mentioned upper plate 43, and the end surface of the metal spring 47 is a flange of the supporting metal piece 49. It is tightly connected to the portion 49a.

According to this embodiment, since the air tank 45 portion of the air spring 21B is embedded in the waffle slab 23, the height dimension occupied by the two-layer seismic isolation device 21 can be reduced, The effective height dimension of the clean room 1 can be increased. Further, since the metal spring 47 has a characteristic that the smaller the distance between the end faces is in comparison with the length in the horizontal direction, the higher the horizontal rigidity becomes and the lower the vertical rigidity becomes. Therefore, in the present embodiment, the intermediate plate 29 and the support metal 49. Since the distance to the flange portion 49a of the
As a result that the distance between the end faces of 7 is inevitably small, the metal spring 4
The horizontal length of 7 can be shortened, and the leaf spring having the same spring characteristics can be miniaturized.

As described in the above embodiment, the present invention is not applied only to the clean room,
It goes without saying that the present invention can also be applied to a structure to be seismically isolated, for example, a building such as an office building, an apartment house, or a general house. In this case, for example, the laminated rubber isolator may be fixed to the base side and the air spring may be fixed to the structure side.

[0031]

As described above, according to the present invention, when a large earthquake occurs, the pair of plates (laminated rubber) undergo a large relative deformation in the horizontal direction, and all the laminated layers are accompanied by this deformation. Even if the overlapping area where the rubber is projected on a plane becomes small, the large load of the structure is supported by the column, so there is no need to install a laminated rubber isolator with a large supporting area in advance, and waffle slabs, etc. The natural frequency of the seismic isolation structure can be made lower than the frequency band of the seismic waveform, which can be easily avoided, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a clean room to which the present invention is applied.

FIG. 2 is an enlarged sectional view of the seismic isolation device according to the present invention.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a view taken in the direction of arrow IV in FIG.

FIG. 5 is a correlation diagram between the horizontal deformation of the laminated rubber and the supporting load borne by the laminated rubber and the column.

FIG. 6 is a sectional view showing another embodiment.

[Explanation of symbols]

 1 Clean Room 19 Frame 21 Seismic Isolation Device 21A Laminated Rubber Isolator 21B Air Spring 23 Waffle Slab 27 Seismic Isolation Platform 29 Vibration Absorber 30 Lower Plate 31 Intermediate Plate 32 Steel Plate 33 Rubber (Laminated Rubber) 37 Column 39 Low Friction Material Block (Low) Friction part) 43 Upper plate 47 Metal spring

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area F16F 15/04 8312-3J F16F 15/04 E

Claims (4)

[Claims] 1. A plurality of laminated rubbers in which a rubber plate and a steel plate are alternately laminated in a sandwich form are arranged between a pair of plates facing each other in the vertical direction, and the lower one of the plates located above is arranged. A column body for supporting a vertical load is vertically erected fixedly, and a lower end of the column body is a low friction portion capable of sliding contact facing the upper surface of the plate located below, and the upper surface of the plate located below is A seismic isolation device characterized by mirror finishing. 2. The seismic isolation device according to claim 1, wherein the laminated rubber is arranged around the column. 3. The seismic isolation apparatus according to claim 1, wherein an air spring for suppressing vertical vibration is integrally provided on an upper portion of the plate located above the plate. 4. The seismic isolation apparatus according to claim 3, wherein the air tank portion of the air spring is embedded in the seismic isolation target.