JPS63289344A - Vibro-isolating support device - Google Patents

Abstract

PURPOSE:To make a large vibration in the horizontal direction absorbable by installing an air spring and a laminated rubber vibration isolator, extending each cylinder body of both inner and outer cylinders to the lower part from a diaphragm lower end, and attaching a sliding member to a clearance in this extended part in the circumferential direction. CONSTITUTION:When a large roll acts on a vibro-isolating support device, an outer cylinder 3, receiving horizontal force, comes into contact with an inner cylinder 5 via the sliding member 20 attached to the clearance in the circumferential direction without contacting with the inner cylinder 5 directly. Consequently, vertical relative motion of these inner and outer cylinders 5 and 3 is almost in no case checked and, what is more, a diaphragm 4 forming an air spring 1 receives no damage so that, even if such a case, function of the vibro-isolating support device is maintainable. That is, vertical movements are absorbed by the air spring 1, while horizontal movements by a laminated rubber vibration isolator 2, respectively, thus a vibro-isolating function can be brought into full play.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a seismic isolation support device for a nuclear reactor building, reactor related equipment, other important structures, etc.

<Prior Art and its Problems> If an important structure such as a nuclear reactor is destroyed by an earthquake, it may cause a serious disaster, so it has been proposed to have a seismic isolation structure including the building.

The base isolation structure focuses on the fact that the peak frequency of earthquakes is 5 to 10 Hz, and the natural frequency of heavy objects supported by springs is set to 1.
By setting the frequency to Hz or less, the vibration transmitted from the ground to the heavy object is absorbed and blocked by the spring.

One such spring device for seismic isolation is a laminated seismic isolation rubber. As shown in Fig. 4, the laminated seismic rubber is made by stacking thin rubber ib and steel plates C alternately between two upper and lower steel plates a and a and bonding them together. Due to the elastodynamic properties of rubber, such laminated foreshock rubber has the characteristics that it is rigid and has a large spring constant against loads in the vertical direction, and has a small spring constant against loads in the horizontal direction. The ratio of the spring constant in the horizontal direction and the spring constant in the horizontal direction may be as high as 100 times. When such a laminated forearthquake rubber is used as a support device, there is a problem in that although seismic isolation in the horizontal direction can be obtained, seismic isolation in the vertical direction cannot be achieved by 1q.

On the other hand, as one type of spring device, there is an air spring as shown in FIG. As shown in the figure, it has a structure in which a rubber membrane r with a U-shaped cross section is provided between a metal cylinder (gaisho) d and a piston (inner cylinder) e. The entire expansion and contraction is performed by It counteracts external force by the pressure of air sealed inside.In response to changes in external force in the vertical direction, the shilling and piston move relative to each other and the internal volume changes, which changes the pressure and counteracts the external force. It is designed to be balanced.

In response to an external force in the horizontal direction, as shown in Figure 6, when the rubber membrane is displaced by δ in the lateral direction, the 0 character of the rubber membrane on the pressed side hangs downward, and the lateral pressure-receiving area increases. On the other side, the pressure-receiving area decreases, creating a difference in the pressure-receiving area, and this difference is approximately proportional to the displacement δ, so that a restoration force proportional to the displacement δ acts.

When such an air spring is used as a seismic isolation support device, seismic isolation in the vertical and horizontal directions can be obtained, but it is difficult to obtain a sufficient permissible stroke in the horizontal direction due to the strength of the rubber membrane.
The problem is that it cannot withstand large earthquakes.

In order to solve this problem, a seismic isolation support device shown in FIG. 3 has been proposed (Japanese Patent Application No. 61-229766).

In Figure 3, 1 is an air spring, 2 is a laminated foreshock rubber, and 3
is an outer cylinder, 4 is a diaphragm, 5 is an inner cylinder, 6 is a rubber stopper, 7 is an inner cylinder rubber, 8 is an outer cylinder rubber, 9 is a dew-proof rubber,
10 is an annular steel plate, and 11 is a lower steel plate.

As shown in the figure, the air spring 1 has a structure in which a diaphragm 4 is provided between an outer cylinder 3 and an inner cylinder 5.
have a structure in which cylinders 3b and 5b are concentrically welded to disks 3a and 5a, respectively, and the space between the outer cylinder 2 and the inner cylinder 5 is sealed by a diaphragm 4 and filled with pressurized air. ing.

A cylindrical stopper 6 made of rubber is fixed to the upper surface of the inner cylinder, and comes into contact with the lower surface of the disk 3a of the outer cylinder to support the outer cylinder 3 when the air is removed. An outer cylinder rubber 8 and an inner cylinder rubber 7 are fixed to the inner surface of the outer cylinder 3b and the outer surface of the inner cylinder 5b, respectively, to protect the diaphragm 4. A laminated foreshock rubber 2 is fixed to the lower surface of the cylindrical disk 5a, and a lower steel plate 11 is fixed to the lower end of the laminated seismic insulation rubber.

If the laminated foreshock rubber 2 is a solid cylinder, the diameter will be too small if the required spring constant is set, and there is a risk of buckling, so a hollow cylinder as shown in the figure is used.

As shown in the figure, the laminated foreshock rubber 2 has a structure in which a large number of annular steel plates 10 are embedded and bonded to a cylindrical dew-proof rubber 9.

In addition, the laminated foreshock rubber 2 has a large rubber thickness between the steel plates 10,
If the spring constant in the vertical direction is small, the load will be large, which may cause creep, which is undesirable. Usually, the ratio of the spring constants in the vertical direction and the horizontal direction is 100 to 1000 times.

The vertical vibration of an earthquake is transmitted from the lower steel plate 11 to the inner cylinder 5 of the air spring via the laminated foreshock rubber 2, but the air spring 1
Since the signal is blocked by , it is not transmitted to the building. In addition, horizontal vibrations are absorbed by the laminated foreshock rubber 2 and air spring 1,
Moreover, since the permissible displacement of the laminated foreshock rubber 2 is large, even if the lateral width of the earthquake exceeds the permissible stroke of the air spring 1, vibrations will not be transmitted to the building.

The seismic isolation support device shown in FIG. 3 as described above has the following problems. In other words, when attempting to absorb large lateral vibrations with a horizontal stroke of more than 10 centimeters, the horizontal permissible swing of the air spring is small and the lateral spring constant cannot be set very large due to the design. (In other words, it cannot be made into a very hard spring), so the inner cylinder 2 and outer cylinder 5 are set to = 6.
− They come into contact with each other. If this happens, the vertical movement of the air spring will be hindered, and there is a risk that the diaphragm 4 will be damaged, making it unable to function as a seismic isolation support device.

<Object of the invention> The present invention has been devised in view of the problems of the prior art.
Therefore, it is an object of the present invention to provide a seismic isolation support device that can absorb large horizontal vibrations.

<Means for Solving the Problems> In order to achieve the above object, the seismic isolation support device of the present invention includes an outer cylinder, an inner cylinder, and a diaphragm that connects the two cylinders to form a sealed space between the two cylinders. It comprises an air spring and a laminated earthquake-proofing rubber fixed to the lower surface of the top plate of the inner cylinder of the air spring, and the cylindrical bodies of the outer cylinder and the inner cylinder extend downward from the lower end of the diaphragm, and the annular gap of the extended part It is characterized in that a sliding member is attached in the circumferential direction.

<Function> When a large lateral vibration acts on the seismic isolation support device of the present invention, the outer cylinder that receives the horizontal force does not come into direct contact with the inner cylinder,
Since they come into contact via a sliding member, the relative movement of the inner and outer parts in the vertical direction is hardly hindered, and the diaphragm is not damaged, so the function of the seismic isolation support device is maintained even in such cases. be done. That is, the vertical movement is supported by air springs, and the horizontal movement is supported by laminated seismic isolation rubber, which exerts a seismic isolation function.

<Example> An example of the present invention will be described below with reference to the drawings. Fig. 1 is a sectional view of the seismic isolation support device of the present invention, and Fig. 2 is a sectional view of I[''4 in Fig. 1. In Fig. 1 and Fig. 2, 1 is an air spring, and 2 is a laminated seismic isolation rubber. , 3 is the outer cylinder, 4
is a diaphragm, 5 is an inner cylinder, 6 is a rubber stopper, 7
is an inner cylinder rubber, 8 is an outer cylinder rubber, 9 is a foreshock rubber, 10 is an annular steel plate, 11 is a lower steel plate, 12 is a gap, 3C15C is a cylindrical body of the inner cylinder and outer cylinder, respectively, 20 is a sliding member, 2
1 is a rib for increasing the rigidity of the cylindrical body 3C15C.

The seismic isolation support device of the present invention shown in FIG. 1 is a partial improvement of the conventional seismic isolation support device shown in FIG. The explanation will be omitted.

As shown in FIG. 1, the cylindrical body 3C15C of the inner cylinder 3 and outer cylinder 5
extends downward from the U-shaped portion of the diaphragm, and a sliding member 20 is attached near the lower end of the inner cylinder 3C in the gap 12 between the two rotating cylinders. The sliding member has a block shape obtained by cutting an annular member at equal intervals in the circumferential direction, and a solid film lubricant 20a such as Lubribond (trade name) is adhered to the sliding surface at the tip.

The mounting position of the sliding member 20 on the support device in the height direction is preferably at the same level as approximately the middle height of the laminated seismic insulating rubber 2. That is, when the outer cylinder 5 receives a horizontal force and is transmitted to the inner cylinder via the sliding member 20, a bending moment is generated in the laminated seismic insulation rubber as shown in FIG. The moment becomes zero at the middle height of the seismic isolation rubber 2, and the absolute value of the maximum value of the moment is the smallest in this state. This is because the resistance is the greatest.

The sliding member 20 may be attached to the inner surface of the cylindrical body 5C of the outer tube 5, or may be attached to both the inner tube and the outer tube. Further, the sliding member 20 may be annular instead of block-shaped, or may be of an anti-friction type with rollers or balls built therein.

Next, the effect will be explained.

With the structure described above, horizontal force is transmitted from the outer cylinder 5 to the inner cylinder 3 via the sliding member 20. Therefore, the seismic isolation performance in the horizontal direction is entirely dependent on the laminated seismic isolation rubber 2. On the other hand, the vertical seismic isolation performance is air splash 1
However, when horizontal and vertical vibrations are applied simultaneously, the sliding member 20 is interposed between the inner and outer cylinders, and the inner and outer cylinders are free to move relative to each other in the vertical direction. Therefore, both horizontal and vertical seismic isolation functions can be achieved.

<Modified example> FIG. 8 is a partial sectional view showing a modified embodiment of the present invention.

In this example, the sliding member is removed leaving an appropriate gap 13 in the gap 12 between the inner and outer cylindrical bodies 3C150.

In this example, since the -C air spring generates a reaction force against the horizontal force, it is desirable to lower the U-shaped lower end of the diaphragm to just above the sliding member 20 as shown in the figure.

As described above, since the gap 13 is formed between the tip of the sliding member 20 and the inner surface of the cylindrical body 5C of the outer cylinder, when the horizontal swing width is small, the sliding member 20 moves to the cylindrical body 5C.
There is no contact with the metal, there is no sliding resistance, and the vibration isolation function is better than that of the conventional one (
(See Figure 3). For example, change gap 13 to 10
mm, and if the horizontal spring constant of the air spring 1 and the laminated seismic insulation rubber 2 is 3:1, then if both widths of horizontal vibration are less than 80 mm, the sliding member 20 and the inner surface of the cylindrical body 5G does not come into contact.

<Effect of the invention> As described above, the present invention has the following effects.

(1) Since a sliding member is interposed between the inner and outer cylinders so that the inner and outer cylinders are in contact with each other, the seismic isolation support HH can sufficiently cope with large vibrations in the horizontal direction.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the seismic isolation support device of the present invention, and Fig. 2 is a sectional view of the seismic isolation support device of the present invention.
Figure 3 is a cross-sectional view of a conventional seismic isolation support device, Figure 4 is a side view of a laminated seismic isolation rubber, Figure 5 is a cross-sectional view of an air spring, and Figure 6 is a cross-sectional view of a conventional seismic isolation support device. FIG. 7 is a cross-sectional view illustrating the mechanism by which a restoring force is generated when a horizontal load is applied to an air spring, FIG. 7 is a bending moment diagram against a horizontal load, and FIG. 8 is a partial cross-sectional view of a modified example. 1... Air spring 2... Laminated seismic rubber 3... Outer cylinder 4... Diaphragm 5... Inner cylinder 20... ...Sliding member Fig. 4 Fig. 5 e Fig. 6 ``-1 pattern Fig. 7 Fig. 8 Year≠δ)

Claims (1)

[Scope of Claims] 1) An air spring consisting of an outer cylinder, an inner cylinder, and a diaphragm that connects the two cylinders to form a sealed space between the two cylinders, and a lower surface of the top plate of the inner cylinder of the air spring. The cylindrical bodies of the outer cylinder and the inner cylinder extend downward from the lower end of the diaphragm, and a sliding member is installed in the annular gap in the extended part in the circumferential direction. Seismic isolation support device. 2) The seismic isolation support device according to claim 1, wherein the sliding member is attached with a required gap left between the inner and outer cylinders. 3) The seismic isolation support device according to claim 1, wherein the sliding member is attached without any gap between the inner and outer cylinders. 4) The seismic isolation support device according to claims 1 to 3, wherein the mounting position in the height direction of the sliding member support device is at the same level as approximately the middle height of the laminated seismic insulation rubber.