JPH0439968Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to vibration isolators, and in particular improves the horizontal spring characteristics of vibration isolators used in structures such as buildings.

[Conventional technology]

BACKGROUND ART Conventionally, as a device (seismic isolation device) for preventing damage caused by vibrations when an earthquake occurs to structures such as buildings and nuclear reactors, a device having a structure shown in FIG. 4, for example, has been used. This seismic isolation device is formed into a cylindrical solid structure in which reinforcing thin steel plates 2 are buried in parallel at appropriate intervals inside an elastic support 1 made of rubber, etc. Pressure receiving plates 3 and 4 are attached to each.

[Problem that the invention attempts to solve]

Generally, the elastic support of the seismic isolation device is formed into a shape that has a height and outer diameter that will not buckle even when horizontal displacement occurs due to an earthquake. Therefore, if this elastic support is installed in a place where the vertical support load is small, such as in a lightweight structure, the horizontal natural frequency may be below the allowable value, although the horizontal allowable displacement can be secured. The vibration isolation performance will deteriorate if the

In addition, in this case, if you try to secure the allowable natural frequency in the horizontal direction and prevent the deterioration of vibration isolation performance,
It is necessary to reduce the horizontal spring constant by molding the outer diameter of the elastic support to a smaller size, but in this way, the amount of horizontal displacement is restricted to the limit that does not buckle, ensuring the allowable amount of displacement. The problem is that it becomes impossible to do so.

This idea solves the above problems, has a shape with a small horizontal spring constant, has high buckling strength, and can ensure the horizontal permissible displacement and permissible natural frequency even when the supporting load is small. Also, in order to prevent resonance of the vibration isolator, it is necessary to have a vibration damping force, but it is necessary to provide a vibration isolator that also has this effect and does not require the addition of a special damping device such as a friction damper. The purpose is to provide.

[Means for solving problems]

The vibration isolator of this invention includes an elastic support made of a flexible material such as rubber, provided with hollow portions opening at both upper and lower ends along the vertical central axis, and pressure receiving plates attached to both upper and lower ends of the elastic support. A plurality of sliding plates are stacked in the hollow part to approximately the same height as the hollow part, so that the sliding plates can mutually slide horizontally.

[Effect]

In normal times, the vertical load applied to the vibration isolator of this invention is not only supported by the entire plane of the elastic support when it is in an upright state, but also distributed and supported by the entire plane of the sliding plate. be done.

When the vibration isolator receives a horizontal force due to an earthquake, the force due to the horizontal displacement of the elastic support is applied to the sliding plates, causing the sliding plates to slide against each other, causing the hollow part of the elastic support to It moves horizontally in the same shape as the deformed shape and tilts in a step-like manner.

When the vibration isolator is horizontally displaced, the area of the overlap between the vertical projection plane of the upper end surface and the fixed lower end surface at the position of displacement between the elastic support and the sliding plate is equal to the overlapping area of the elastic support. The vertical load applied is supported by the elastic support, and the vertical load applied to the other overlapping area is supported by the sliding plate.

Since the elastic support of the vibration isolator has a hollow part, the spring constant in the horizontal direction is smaller than that of a solid elastic support with the same outer diameter, and the permissible horizontal displacement is small even when the supporting load is small. and the allowable natural frequency can be secured.

Assuming that the horizontal spring constants of the elastic support of the vibration isolator of this invention and the solid elastic support are the same, the elastic support of this invention has a greater Since the ratio of the diameter dimensions can be set to a large value, the vibration isolating device does not undergo buckling deformation even if a large horizontal displacement occurs.

Furthermore, vibration isolators need to have damping force in order to prevent resonance, but this idea generates damping force by the frictional force between sliding plates, and adds a damping device such as a friction damper. It is not necessary to do so, or the damping device to be added can be made smaller or less. In addition, buildings tend to sway easily due to wind loads, etc., or it is often desirable to fix them to the ground against weak vibrations such as small earthquakes that do not require vibration isolation. This invention has a triggering action that operates only in response to a vibration force of a certain force or more due to the static friction force of the sliding plate, so it can provide desirable vibration-proofing performance suitable for this purpose.

〔Example〕

Hereinafter, embodiments of this invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional side view showing an embodiment of this invention.

In the figure, numeral 10 is an elastic support body,
This elastic support body 10 has annular elastic plates 11 made of a flexible material such as rubber and reinforcing plates 12 made of thin steel material, which are alternately stacked in multiple stages, and annular top plates are provided on the upper and lower end surfaces, respectively. 14 and a lower plate 16 are concentrically bonded and formed into a hollow cylindrical shape.

The upper surface plate 14 and the lower surface plate 16 of the elastic support body 10
, the pressure plates 15 and 17 are connected to the bolts 18 and 17, respectively.
19, and both upper and lower ends of the elastic support 10 are closed.

The hollow part 13 of the elastic support body 10 has a hollow part 13
A plurality of sliding plates 20 are housed stacked at almost the same height. This sliding plate 20 is formed into a flat plate shape from a material that has a high resistance to compressive force, such as steel, other urethane plates, or synthetic resin plates, and can slide horizontally relative to each other in a stacked state. However, depending on the molding material, it is preferable to use a material whose front and back surfaces are coated with fluororesin or other material having an appropriate coefficient of friction.

When the vibration isolator with the above configuration is installed between a structure such as a building and a floor surface such as the ground, the load applied in the vertical direction is equal to the entire plane of the elastic support 10 in the normal upright state. , and the entire plane of the sliding plate 20 laminated in the hollow part 13, the elastic support 10 only needs to partially bear the entire load, and the compression received by the elastic support 20 is The stress will be lower than in the case of a simple hollow body.

In addition, in the event of an earthquake, please refer to Figures 2 and 3.
As shown in the figure, the elastic support 10 is displaced and tilted in the horizontal direction, and along with this, the elastic support 10 is laminated in the hollow part 13 by the inner peripheral surface on the side receiving horizontal force. Since a pressing force is applied to the sliding plates 20 that are in the
It becomes an inclined step-like shape having the same shape as the shape at the time of deformation of 0.

When the elastic support 10 is deformed in the horizontal direction in this way, the elastic support 10 is The elastic support 10 supports a part of the load in the vertical direction due to the overlapping area 24a of the elastic support 10, and most of the remaining load is supported by the overlapping area 24b of the elastic support 10 excluding the overlapping area 24a. Since the sliding plate 20 supports it, the compressive stress generated in the elastic support body 10 does not increase in this case as well.

Therefore, even if the elastic support 10 is formed into a hollow shape, unlike a simple hollow body in which the sliding plate 20 is not laminated, the increase in the compressive strain of the elastic support 10 due to a vertical load is small, so that the creep phenomenon is prevented. can be significantly reduced.

In addition, since the elastic support 10 of the above-mentioned vibration isolator is provided with the hollow part 13, the horizontal rigidity is lower than when the elastic support 10 is molded to have the same outer diameter as the solid elastic support. Since the spring constant is small, not only can a large displacement in the horizontal direction be obtained even when the vertical support load is small, but also the natural frequency is small, so the vibration isolation performance does not deteriorate.

Furthermore, when the elastic support 10 of the vibration isolator is formed to have the same spring constant in the horizontal direction as the solid elastic support, the elastic support 10 has a larger spring constant than the solid elastic support if the height dimension is the same. Since it can be set to the outer diameter dimension, buckling deformation will not occur even if large horizontal displacement occurs when an earthquake occurs.

During the operation of the vibration isolator described above, even if the sliding plate 20 laminated in the hollow part 13 of the elastic support 10 moves horizontally due to the horizontal displacement of the elastic support 10, the sliding plate 20 itself Since there is no force to restore the original shape, the spring constant of the elastic support 10 in the horizontal direction is not affected in any way.

The above-mentioned vibration isolator can obtain not only the vibration isolation effect by the elastic support 10 but also the damping effect by the frictional resistance of the sliding plate 20 laminated in the hollow part 13, as well as the static friction of the sliding plate 20. By appropriately selecting the resistance, it can also be used as a vibration isolator with a trigger function that causes horizontal displacement when the force applied in the horizontal direction exceeds a certain limit.

In addition, since the sliding plate has the effect of hindering and preventing buckling of the elastic support, it is possible to increase the height of the elastic support compared to its diameter, which reduces the amount of deformation strain within the elastic support. This can increase resistance to deformation fatigue and extend life. Therefore, it is possible to design a vibration isolating device with a small size, and it is possible to have a vibration isolating device that has a sufficient vibration isolating effect for a support with a low load.

Since the elastic support 10 of the above embodiment has a laminated structure of the elastic plate 11 and the reinforcing plate 12, the circumferential surface of the elastic support 10 touches the sliding plate 20 when the elastic support 10 is horizontally displaced. Although the elastic support 10 does not deform significantly outward in the radial direction even when abutting against each other, a tire cord is attached to the inner circumferential side of the elastic support 10 in order to prevent damage to the rubber due to movement of the sliding plate 20. Alternatively, a structure in which a reinforcing material is provided in a cylindrical shape using woven fabric, wire mesh, a coil spring, or the like may also be used.

Further, in the present invention, it is also possible to omit the reinforcing plate 12 of the elastic support 10 and use one constructed only of elastic bodies.

In the above embodiment, the elastic support has a cylindrical shape in which the outer diameter and inner diameter are constant with respect to the vertical central axis, but the cross-sectional shape of the elastic support has a hollow portion along the vertical central axis. The shape may be any shape as long as it has a shape, and the design can be changed to any shape depending on the desired horizontal spring constant.

The vibration isolator of this invention is not limited to being used as a seismic isolation device for structures such as buildings as described in the above embodiments, but can also be used as a vibration isolator for vibration-generating machines.

[Effect of idea]

As explained above, the vibration isolator of this invention is
Since the structure is such that a plurality of sliding plates are stacked in a hollow part provided along the vertical center axis of the elastic support so that they can slide freely in the horizontal direction, even when the elastic support is horizontally displaced, the vertical direction remains unchanged. The load is shared and supported by the elastic support and the sliding plate, and the creep characteristics do not deteriorate as in the case of the elastic support alone.
In addition, the spring constant in the horizontal direction is smaller than that of a solid elastic support, and it can be formed into a shape with a larger outer diameter than a solid elastic support with the same spring constant in the horizontal direction, resulting in buckling deformation. A large horizontal displacement can be obtained without causing

Therefore, according to this invention, even when the vertical support load is set small, large horizontal displacements can be achieved without increasing the natural frequency in the horizontal direction and while keeping the strain deformation of the elastic support body small. The horizontal spring characteristics and durability of conventional vibration isolators of this type are improved, and the vibration isolators of this invention have their own frictional damping force, so a special damping device is required. It can be omitted or reduced, and it is fixed to the ground or floor surface for vibrations that do not require vibration isolation such as wind loads and small earthquakes, and is suitable for buildings, etc. It is an effective device to have as a seismic isolation device for structures.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional side view showing an embodiment of this invention;
FIG. 2 is a plan view showing the state of the elastic support of this invention during horizontal displacement, FIG. 3 is a vertical side view of FIG. 2,
FIG. 4 is a longitudinal sectional side view showing a conventional vibration isolator. In the figure, 10 is an elastic support, 13 is a hollow part, 1
5 and 17 are pressure receiving plates, and 20 is a sliding plate.

Claims (1)

[Scope of utility model registration request] The upper and lower ends of an elastic support body made of a flexible material such as rubber and provided with hollow parts opening at both upper and lower ends along the vertical central axis are closed by pressure receiving plates, and a plurality of hollow parts are inserted into the hollow part of the elastic support body. A vibration isolating device characterized in that a plurality of sliding plates are laminated to be horizontally slidable and at approximately the same height as a hollow part.