JPH03265729A - Viscous damper - Google Patents

Abstract

PURPOSE:To equalize resistance at the time of both extension and compression even when high viscous fluid is used by constituting high viscous fluid to come in contact with air via a variable volume member by means of an air chamber which is provided underneath the container of a viscous damper, or of hole sections bored in the container. CONSTITUTION:High viscous fluid 6 is filled in a container 3, an air chamber 9 is made up out of a cylindrical section acting as a bottom section member 8 and a rubber member 7, and a resisting member 4 is provided with hole sections 5 so that high viscous fluid 6 located above and beneath the resisting member 4 can be moved. When the resisting member 4 is moved downward with respect to the container 3, the resisting member 4 intends to compress high viscous fluid 6, no great pressure is however built up because the rubber member 7 is deformed by high viscous fluid 6, shearing viscous resistance of high viscous fluid 6 between the container 3 and the resisting member 4, in this case, thereby dominates resisting force by a viscous damper. When the resisting member 4 is moved upward, no great pressure is built up either because high viscous fluid 6 located above the resisting member comes in contact with air.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for preventing a sudden increase in resistance force during compression in an axial viscous damper using a high viscosity fluid, and in particular to a seismic isolation device. The present invention relates to a viscous damper suitable for.

[Conventional technology]

A conventional axial viscous damper using a high viscosity fluid stores a high viscosity fluid and a resistance member in a cylindrical container, as described in Japanese Patent Laid-Open No. 63-114783 (Fig. 7).
The gap between the resistance member and the container is kept uniform. This viscous damper utilizes the shear viscous resistance force generated by the high viscosity fluid between the outer diameter part of the resistance member and the inner diameter part of the container when the resistance member moves in the axial direction.

[Problem to be solved by the invention]

Even in the conventional viscous damper, in order to prevent excessive pressure from being applied to the high viscosity fluid below the resistance member during compression when the resistance member moves downward, the high viscosity fluid above and below the resistance member presses against the resistance member. A hole is provided in the resistance member for access through the resistor member.

However, if the viscous fluid used has an extremely high viscosity, a large resistance force will be generated when it passes through the hole in the resistance member, so the resistance curve of the viscous damper will change as shown in Figure 8. This results in an asymmetric hysteresis characteristic in which the force increases rapidly, which may reduce the damping effect of the vibration system.

An object of the present invention is to provide a viscous damper that has the same resistance force during compression and tension even when a high viscosity fluid is used.

[Means to solve the problem]

In order to achieve the above object, an air chamber is provided below the container of the viscous damper, or a hole is provided in the container, so that the high viscosity fluid and air come into contact with each other via a variable volume member. This variable volume member is made of an elastic body such as rubber, a metal bellows, or the like.

[Effect]

When the resistance member inside the viscous damper container moves downward (in the compression direction), the high viscosity fluid pushed by the resistance member deforms the variable volume member and compresses the air in the air chamber, but the pressure does not become that large. .

Therefore, the resistance force does not increase as dramatically as shown in FIG. 7 even during compression, and the change in resistance force during compression and tension becomes smaller. Furthermore, if the air chamber is communicated with the atmosphere, the resistance force of the viscous damper during compression can be reduced to only the shear viscous resistance force acting between the container and the resistance member.

Moreover, even if the container does not have an air chamber, the same effect can be obtained by providing a hole in a part of the container and covering it with a volume variable member.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure shows a longitudinal cross-sectional view of a viscous damper of a seismic isolation device according to an embodiment of the present invention. The rod member 1 of the viscous damper is attached to the upper member between the members where relative displacement occurs, and the bottom member 8 is attached to the other member. A cylindrical member having the same diameter as the container 3 stands up on the bottom member 8, and this cylindrical member and the container 3
A flat rubber member 7 is provided between the respective flanges to divide the space between the container 3 and the bottom member 8. The container 3 is filled with a high viscosity fluid 6, and an air chamber 9 is formed by the cylindrical portion of the bottom member 8 and the rubber member 7.

Air holes 10 may be provided in the bottom member 8. Further, the resistance member 5 is inserted into a container 2 containing a high viscosity fluid 6, a rod member is fixed to the resistance member 5, and the rod member 1 is supported by a bearing 2 provided in the container 3. . Further, the resistance member 5 is provided with holes 53- through which the high viscosity fluid 6 above and below it can move.

Next, FIG. 2 shows another embodiment. In this embodiment, a convex rubber member 7 is provided inside the container 3, the rubber member 7 and the bottom member 8 form an air chamber 9, and the bottom member 8 is provided with air holes 10.

In the embodiment shown in FIG. 3, a rubber or metal bellows member 11 is provided inside the container 3 to secure an air chamber 9, and the bellows member l
If the spring constant in the axial direction of the shaft is small, a spring member 13 for pushing up may be added.

In the embodiment shown in FIG. 4, an air-filled rubber ball 13 filled with air is provided in the container 3 as an air chamber, so that the air ball 13 does not move around when the resistance member 4 is moved.
The movement of the air-filled rubber ball is suppressed by the net member 14 or the like.

In the embodiment shown in FIG. 5, a hole is provided in the side surface of the container 3, and a bag-shaped rubber member 7 is attached to the outside of the container 3 so that the holes of the container 3 and the rubber member 7 match.

In the embodiment shown in FIGS. 1 to 5, the bearing 2 functions to maintain a uniform gap between the resistance member 44- and the container 3, but in the embodiment shown in FIG. This function is achieved by arranging a low-friction material 15 around the . Furthermore, to prevent the high viscosity fluid 6 from flowing out of the container 3,
A bellows member 11b is attached between the container 3 and the rod member l. Furthermore, if necessary, an air hole 10b may be provided in the bellows member 11b.

Next, the operation of this embodiment will be explained.

When a relative displacement occurs between the rod member 1 and the bottom member 8,
The resistance member 5 moves up and down inside the container 3. Resistance member 5
When the resistance member 5 moves downward relative to the container 3, the resistance member 5 attempts to compress the high viscosity fluid below it, but as the high viscosity fluid 6 deforms the rubber member 7, the high viscosity fluid 6 is compressed. No large pressure is generated. Therefore, the resistance force caused by the viscous damper is dominated by the shear viscous resistance force caused by the high viscosity fluid between the container 3 and the resistance member.

On the other hand, when the resistance member 5 moves upward, the high viscosity fluid 6 above the resistance member 5 is in contact with air, so no large pressure is generated.

As described above, the viscous damper of the present invention can provide approximately the same resistance force during compression and tension.

〔Effect of the invention〕

According to the present invention, it is possible to prevent a sudden increase in resistance force in the compression direction in a uniaxial viscous damper using a high viscosity fluid.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing one embodiment of the viscous damper of the present invention, and FIGS. 2, 3, 4, 5, and 6 all show other embodiments of the present invention. Longitudinal cross-sectional view of the viscous damper, No. 7
The figure is a longitudinal sectional view of a conventional viscous damper, and FIG. 8 is a characteristic diagram showing a resistance Kerr displacement curve of the conventional viscous damper. 1... Rod member, 2... Bearing, 3... Container, 4
... resistance member, 5 ... hole, 6 ... high viscosity fluid,
7... Rubber member, 8... Bottom member, 9... Air chamber,
10... Air hole, work 1... Bellows member, 12...
・Push-up spring member, 13... Air-filled rubber ball, 1
4...Net member, work 5...Low friction member. 7- \”4 'Q Call' ON) CKs c> Cs-7
Also N 167-

Claims (1)

[Claims] 1. A viscous damper comprising a container storing a high viscosity fluid and a resistance member, characterized in that a variable volume member is provided in contact with the high viscosity fluid surrounded by the container and the resistance member.