JPH1130278A - Base isolation construction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To aim at an improvement in base isolation effectiveness by elastically supporting a superstructure in the vertical direction in relation to its downward substructure via a belleville spring in a state of being added with preload pressure, in use of a nonlinear spring domain where a variation in resiliency becomes lessened to a spring deformed variable. SOLUTION: A belleville spring 16 is installed in space between a floor face 12 and a support structure 14 by way of having a vertical pair of spring layered products, where plural pieces of belleville spring simples 16a are superposed in the same sense, butted in the reverse direction. Then, floor load acts on this belleville spring 16 as preload pressure, and in the state intact, the belleville spring 16 is set up in the range of a spring characteristic nonlinear spring domain. This nonlinear spring domain means that its variation in resiliency is small to a prospective variation in vertical clearance size S between the floor face 12 and the support structure 14, and within this domain, the belleville spring 16 basically absorbs a vertical vibration while if it is flexurally deformed, frictional force to be produced among belleville spring simples 16a works as its damping force. Accordingly, any vibration in the support structure 14 is absorbed as the belleville spring 16 is turned to a cushioning material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration isolation structure in which an upper structure is elastically supported by a lower structure below the upper structure to suppress external vibrations from being input to the upper structure.

[0002]

2. Description of the Related Art When installing precision equipment such as computer equipment and measurement control equipment, it is necessary to make the installation floor a vibration-isolating floor and to cut off (vibration-isolate) the input of external vibration. . As the vibration-isolating floor, for example, Japanese Patent Publication No. 55-413
No. 84 (Int. Cl. F16F 15/02) or JP-B-63-
Conventionally, there is one disclosed in Japanese Patent No. 6710 (Int. Cl. E04F 15/18). The vibration-isolating floor disclosed in Japanese Patent Publication No. 55-41384 is one in which the floor surface is elastically supported by a coil spring-shaped suspension spring, and the vibration isolation floor disclosed in Japanese Patent Publication No. 63-6710 is disclosed. The oscillating floor elastically supports the floor surface with an air spring.

When the floor surface is elastically supported as described above, the floor surface weight (including the weight of equipment installed on the floor)
By increasing the natural period determined by the rigidity (spring constant) of the elastic support member and the rigidity of the elastic support member, the floor surface can be effectively isolated from external vibration.

[0004]

However, in such a conventional vibration-isolating structure, a spring having a characteristic in which the amount of deformation with respect to a load becomes linear, such as a coil spring or an air spring, is elastically supported. Therefore, it is extremely difficult to increase the natural period of the floor surface because of the balance between the large floor surface weight and the spring rigidity for supporting the floor surface.

That is, when the coil spring is used, it is necessary to reduce the rigidity of the coil spring in order to lengthen the natural period of the floor. The amount of sinking of the spring due to weight increases. For this reason, the coil spring has to absorb large sinking due to the floor weight and the vertical displacement of the floor surface at the time of vibration input. As a result, it is necessary to increase the natural length of the coil spring. Since it is necessary to set a large gap between the floor on which the springs are arranged and the support base, the floor height at which the vibration isolation structure is provided becomes high, and the height of the building becomes unnecessarily high.

On the other hand, when the air spring is used, the natural period of the floor surface can be easily increased because of the low rigidity of the spring. Has little effect, and when the relative displacement of the floor surface with respect to the support base is excessive, the air spring itself buckles and the vibration isolation function cannot be obtained.

In view of the above-mentioned problems, the present invention focuses on the fact that disc springs exhibit non-linear spring characteristics.
By elastically supporting the upper structure with respect to the lower structure using a spring region in which the fluctuation of the resilient force is reduced with respect to the amount of deformation of the disc spring, a longer natural period is ensured and the vibration isolation effect is ensured. It is an object of the present invention to provide a vibration-isolating structure that can improve and reduce a gap between an upper structure and a lower structure to prevent an unnecessary increase in floor height.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, a vibration isolating structure according to the present invention elastically supports an upper structure vertically with respect to a lower structure thereunder via a disc spring, and further comprises a disc spring. Is configured to be used in a state where a preload is applied so as to use a non-linear spring region where the fluctuation of the resilient force with respect to the amount of spring deformation is reduced.

With the above structure, the vibration isolating structure according to the present invention operates in a non-linear spring region in which the elasticity of the upper structure is elastically supported on the lower structure in the vertical direction. In the non-linear spring region of the disc spring used to elastically support the upper structure, the spring stiffness is set to be small because the fluctuation of the resilient force with respect to the amount of spring deformation is small. Therefore, as long as the non-linear spring region is used, the natural period can be lengthened, and the upper structure can be effectively isolated from external vibration. In addition, since the above-mentioned disc spring is literally formed into a dish-shaped and thin shape, a gap between the upper structure and the lower structure in which the disc spring is arranged can be set small, and a building having a vibration isolation structure can be provided. Floor height can be reduced. Further, when an excessive load is applied to the disc spring, the disc spring is deformed by the entire amount of deflection and becomes rigid to support the upper structure, so that it can also have a fail-safe function.

[0010]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 1 to 3 show an embodiment of a vibration isolating structure according to the present invention. FIG. 1 is an enlarged front sectional view showing an attached state of a disc spring constituting the vibration isolating structure. FIG. FIG. 3 is a spring characteristic diagram showing the relationship between the amount of deformation of the disc spring and the load.

That is, the vibration isolating structure 10 of the present embodiment is similar to that of FIG.
As shown in FIG. 3, the floor surface 12 is vertically elastically supported on the support structure 14 therebelow via a disc spring 16, and the disc spring 16 elastically reacts to the spring deformation σ as shown in FIG. Non-linear spring region R in which the fluctuation of the force (load w) is small
Is used in a state in which a preload is applied.

In the vibration isolation structure 10, a double floor is formed by the floor surface 12 and the support structure 14, and the support structure 14 is formed as a floor slab or a foundation.
The floor surface 12 is disposed so as to be vertically displaceable relative to each other with an appropriate gap S provided above the floor 4. The disc spring 16 is interposed between an upper receiving plate 18 attached to the lower surface of the floor surface 12 and a lower receiving plate 20 attached to the upper surface of the support structure 14 so as to face the upper receiving plate 18. You. The disc spring 16 is set with the upper receiving plate 18 and the lower receiving plate 20, and a plurality of the disc springs 16 are arranged between the floor surface 12 and the support structure 14. It supports the weight (including the weight of equipment installed on the floor).

The disc spring 16 is a disc spring 1 shown in FIG.
6a are laminated, and the disc spring unit 16a has a dish shape with an opening 16b formed in the center as generally known. It is known that the load characteristic of the disc spring 16a itself depends on its shape. In this embodiment, when the plate thickness is S and the total deflection is h, as shown in FIG. It is preferable to use a disc spring having a diameter of 1.3 to 1.4. If h / S is less than 1.3, warpage is small and a sufficient amount of deformation cannot be secured, and 1.4 is also obtained.
If it is larger than the above, there is a possibility that the warp may be deformed in the opposite direction. Note that Do is the outer diameter of the disc spring, and Di is the inner diameter of the disc spring. In addition, regarding the combination of the disc springs 16a, in the parallel arrangement in which the disc springs 16a are overlapped in the same direction, if the number of overlaps is two, the resilience is twice as large.
The resilience can be adjusted by the number of the stacked layers, such as three times the resilience. Also, in the series in which the directions of the disc springs are alternately overlapped, the amount of deflection is adjusted by the number of overlaps in the series, such that if the number of overlaps is two, the amount of deflection is double, and if the number is three, the amount of deflection is three times. be able to. Therefore, by variously combining these parallel and serial arrangements, it is possible to set a desired amount of deflection while securing various elasticity.

FIG. 3 shows a spring characteristic A of a vertical restoring force due to a load-displacement of the disc spring 16 having a spring characteristic that can be employed in the present embodiment. The vertical axis of the characteristic shows the floor load input to the disc spring, and the horizontal axis shows the deformation (flexure) of the disc spring 16. Here, in a state where the floor load acts on the disc spring 16, the floor load becomes equal to the elastic force of the disc spring 16 that appears as a reaction force thereof.

In this embodiment, the disc spring 16 is
Is formed by abutting a pair of upper and lower spring laminates in which a plurality of disc springs 16a are stacked in the same direction in opposite directions. When the disc spring 16 is interposed between the floor surface 12 and the support structure 14, the floor load acts on the disc spring 16 as a preload. In this state, the disc spring 16 is set in the range of the non-linear spring region R of the spring characteristic A shown in FIG.
Here, the non-linear spring region R is the floor surface 12 and the support structure 14.
Is a region in which the resilience (w) has a small variation with respect to the expected change amount (σ) of the gap size S in the vertical direction between the disc spring 16 and the disc spring 16. Used to absorb vertical vibration.

The above-mentioned disc springs 16 are freely laminated without being connected to each other, and open when the disc springs 16 are mounted between the floor surface 12 and the support structure 14 as shown in FIG. The portion 16 b is guided by the guide 22, and the guide 22 holds the stacked state and the mounting position of the disc spring 16. When the disc spring 16 is bent and deformed in accordance with the change in the gap S between the floor surface 12 and the support structure 14, the adjacent disc springs 16a rub against each other to generate friction, and this frictional force is generated. It acts as a damping force.

With the above configuration, the vibration isolation structure 1 of the present embodiment is used.
0, the floor surface 12 provided so as to be vertically displaceable relative to the support structure 14 is a disc spring 16 (of course, a disc spring 16
The disc spring 16 can be constituted by a. ), The vibration such as an earthquake input to the support structure 14 is absorbed by the disc spring 16 as a cushioning material, and the transmission of vibration to the floor 12 is greatly reduced. Thus, precision equipment and electronic equipment (not shown) installed on the floor 12 can be effectively protected.

By the way, the disc spring 16 uses a non-linear spring region R in which the variation of the resilient force (load w) with respect to the amount of spring deformation σ is small when the floor surface load of the floor surface 12 is applied. Has become. Therefore, the nonlinear spring region R
In this case, since the fluctuation of the resilient force w with respect to the spring deformation amount σ is small, the spring stiffness is used in a small range. Therefore, as long as the non-linear spring region R is used, the natural period of the floor 12 can be increased while the supporting load w is increased. Therefore, the floor surface 12 can be effectively isolated from external vibration while sufficiently supporting the floor surface load. At this time, in the disc spring 16, the frictional force generated between the laminated disc springs 16a acts as a damping force, and the damping force reduces the responsiveness of a vibration transmitting member. When a larger damping force is required, it is desirable to provide a damping device such as an oil damper.

Further, since the disc springs 16 are formed in a thin shape by literally forming the disc springs 16a, the disc springs 16 are arranged even when the disc springs 16a are stacked. Gap S between floor surface 12 and support structure 14
Can be set small. Therefore, the vibration isolation structure 1
The floor height of the building when 0 is provided can be reduced, and in particular, even when the vibration isolation structure 10 is provided on a plurality of floors, the height of the building can be prevented from becoming too high.

When an excessive vibration is input due to a large earthquake or the like, or when an excessive load is placed on the floor 12, the gap S between the floor 12 and the support structure 14 is greatly reduced. In this case, if the disc spring 16 is deformed by the entire amount of deflection, further deformation is prevented and the floor surface 12 can be rigidly supported. Therefore, the disc spring 16 also has a fail-safe function. It is.

As described above, in the present embodiment, the vibration isolating structure 10 for vertically isolating the floor surface 12 is configured. Therefore, in a building horizontally isolated by an isolator or the like, the vibration isolating structure 1 of the present embodiment is used.
By applying 0, three-dimensional vibration isolation in which the floor surface 12 is isolated in the horizontal direction and the vertical direction becomes possible. Needless to say, the vibration isolation device of the present embodiment is effective not only for earthquakes but also for shaking of buildings due to wind. Further, a single disc spring 16a constituting the disc spring 16
It is needless to say that the combination arrangement is not limited to the disclosed form of the above embodiment, but may be variously changed and combined as long as the setting required for the disc spring 16 of the present invention is possible.

[0022]

As described above, in the vibration isolating structure of the present invention, the upper structure is elastically supported on the lower structure in the up-down direction via the disc spring. Since the non-linear spring region in which the fluctuation of the resilient force is small with respect to the deformation amount is used, the spring rigidity of the disc spring can be set small by using the non-linear spring region. Therefore, by using the nonlinear spring region,
It is possible to lengthen the natural period of the vibration isolation structure,
The upper structure can be effectively isolated from external vibration. Further, since the disc spring is formed in a thin shape, a gap between an upper structure and a lower structure in which the disc spring is arranged can be set small, and the floor height of a building having a vibration isolation structure can be reduced. It is possible to prevent the height of the building from being increased. Further, when an excessive load is applied to the disc spring, the disc spring is deformed by the entire amount of deflection and becomes rigid to support the upper structure. It has the effect.

[Brief description of the drawings]

FIG. 1 is an enlarged front sectional view of a main part showing a mounted state of a disc spring constituting a vibration isolation structure of the present invention.

FIG. 2 is an enlarged sectional view showing one of the disc springs shown in FIG.

FIG. 3 is a restoring force characteristic diagram showing a relationship between a deformation amount and a load of a disc spring constituting the vibration isolation structure of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vibration isolation structure 12 Floor surface 14 Support structure 16 Disc spring 16a Disc spring only R Non-linear spring area

Claims (1)

[Claims] An upper structure is elastically supported vertically with respect to a lower structure below the lower structure via a disc spring, and the disc spring has a non-linear spring region in which a change in elastic force with respect to a spring deformation is reduced. A vibration isolation structure characterized in that it is used in a state where a preload is applied as in the case of using a vibration isolator.