JPH07243473A - Vibration damping device - Google Patents

Abstract

PURPOSE:To form an outer shape in a compact manner through reduction of the number of parts and to improve durability through prevention of application of a tensile force by a method wherein a rubbery resilient substance having both a function to regulate a frequency and a function to damp vibration is brought into contact with the outer periphery of a pendulum rod. CONSTITUTION:A dynamic absorber is mounted on a stay for television camera for monitoring a structure, for example, a highway. Formation of the dynamic absorber is such that a pendulum rod 2 is suspended in a vibrating manner from the inner upper surface of a cylindrical cover 1 through a universal joint 5 and a weight 3 is attached to the lower end of the pendulum rod 2. A cylindrical reaction force plate 4 is protruded from the inner upper surface of the cover 1 in a state to surround the pendulum rod 2 and a cylindrical rubber 6 for regulating a frequency and damping vibration is initially compressed and inserted therebetween. Vibration of a stay 8 is absorbed by the pendulum rod 2 to reduce the generation of vibration, and vibration of the pendulum rod 2 is regulated by a rubber 6 to damp. Namely, the rubber 6 is provided with both a function to regulate a frequency and a function to damp vibration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration damping device applied to a pillar of a television camera for monitoring highways.

[0002]

2. Description of the Related Art FIG. 2 is an explanatory view of a conventional vibration damping device used for a pillar of a television camera for monitoring highways. In the figure, for example, the pillar 8 of the highway monitoring TV camera 7 installed on the bridge pier 13 of the highway 11 is greatly vibrated by the passage of the vehicle, so that the wire 23 is attached between the pillar 8 and the bridge girder 12. To control vibration.

[0003]

However, in the conventional vibration damping device as described above, the wire 23 is easily loosened, and even if there is a temporary effect, it is not a permanent vibration damping measure. In addition, it is not desirable to install the wires 23 and the like in terms of the appearance of the highway 11.

[0004]

SUMMARY OF THE INVENTION A vibration damping device according to the present invention is intended to solve the above problems. A weight cone is attached to a lower end of the vibration damping device and the vibration damping device is hung through a universal joint to swing in all horizontal directions. A pendulum rod and a rubber-like elastic body that is brought into contact with the outer periphery of the pendulum rod with an initial compression force to adjust the frequency of the pendulum rod and attenuate the vibration are characterized.

[0005]

That is, in the vibration damping device according to the present invention, a rubber-like elastic body is initially compressed on the outer periphery of the pendulum rod which is attached with a weight cone at the lower end and is hung by a universal joint and vibrates in all horizontal directions. It is abutted with force to adjust the frequency of the pendulum pole and to damp the vibration, and if this vibration damping device is installed on a structure such as a pillar of a TV camera, the pendulum pole will The vibration of the structure is reduced by absorbing and vibrating the vibration energy. The rubber-like elastic body adjusts and damps the vibration of the pendulum rod. As described above, in the present vibration damping device, the rubber-like elastic body serves both to adjust the vibration frequency of the pendulum rod and to attenuate it, so that the number of members is small and the outer shape is compact. Further, in this vibration damping device, only the rubber-like elastic body is in contact with the pendulum rod, and even if the pendulum rod swings, only the compressive force always acts on the rubber-like elastic body and the tensile force does not act. It is more durable.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an illustration of a vibration damping device according to an embodiment of the present invention. In the figure, the vibration damping device according to the present embodiment is used for a pillar or the like of a highway monitoring TV camera, and a dynamic vibration absorber 9 is attached to the pillar 8 of the highway monitoring TV camera 7 as shown in the figure. . The cover 1 of the dynamic vibration reducer 9 is in the shape of a cylinder whose upper and lower surfaces are closed, and a pendulum rod 2 is suspended from the upper surface of the inside thereof via a universal joint 5 so that the pendulum rod 2 can vibrate. A cone 3 is attached. On the upper surface of the cover 1, a cylindrical reaction force plate 4 is provided so as to surround the pendulum rod 2, and a cylindrical rubber 6 for frequency adjustment and vibration damping is formed between the reaction force plate 4 and the pendulum rod 2. It is initially compressed and inserted between and installed. The pendulum rod 2 is in contact with the initially compressed rubber 6 at the top, and the pendulum rod 2 vibrates while always receiving the repulsive force of the rubber 6 in the compression direction. The diameter of the dynamic vibration reducer 9 is smaller than the diameter of the column 8 of the TV camera 7, and is installed near the top of the column 8. A mounting jig 10 is mounted on the upper part of the pillar 8 so as to wind around the pillar 8, and the dynamic vibration absorber 9 is fixed to the mounting jig 10. The rubber 6 has a cylindrical shape, but the shape does not have to be particularly concerned.

The pendulum rod 2 in the dynamic vibration reducer 9 oscillates by compressing the initially compressed rubber 6 for frequency adjustment and damping.
The pendulum rod 2 has a natural frequency of one degree of freedom, which is equal to the resonance frequency of the column 8 of the TV camera 7 due to the rubber 6, and by installing this dynamic vibration absorber 9 on the column 2, the pendulum rod 2 will be a column. The vibration energy of 8 is absorbed and vibrates, and the pillar 8
Reduce the vibration of. The vibration of the pendulum rod 2 is damped by the rubber 6. The rubber 6 acts both as a rigidity adjuster by, for example, a spring and a damping effect by, for example, a damper. Therefore, the vibration damping device has a small number of constituent members, a compact design is possible, and vibration can be sufficiently suppressed. The outer periphery of the rubber 6 is attached to the reaction force plate 4 fixed in the cover 1, but the inner periphery is only in contact with the pendulum rod 2, and when the pendulum rod 2 shakes, the rubber 6 is always compressed. Only the force acts, not the tensile force, so rubber 6
Has durability. Since the pendulum rod 2 is supported by the universal joint 5, the pendulum rod 2 can freely move in a horizontal plane, and vibration can be suppressed in all directions.

In the conventional vibration damping device, the wire is easily loosened, and even if temporarily effective, it is not a permanent measure. In addition, it is not desirable to install wires and the like on the aesthetics of a highway, but in order to solve the problems of the conventional vibration damping device, this vibration damping device is supported by the universal joint 5 so that it can be freely moved in the horizontal plane. A pendulum rod 2, a weight 3 that can be moved to, and a dynamic vibration absorber 9 that is composed of rubber 6 that also has the characteristics of frequency adjustment and damping. 8
Since it is compact and can be attached to the top of the pillar 8 of the TV camera 7, there is no problem in terms of appearance, and the pillar 8 of the existing TV camera 7 can be easily mounted via the mounting jig 10. It can be installed without losing its aesthetic appearance. Further, since the characteristics of the rubber 6 are used as the damping characteristics, an oil damper or the like is not required, and the cost is reduced, and the outer shape is small and compact. Also, rubber 6
Since is initially compressed and is in contact with the pendulum rod 2, there is no rattling, and smooth vibration characteristics can be obtained.

[0009]

Since the vibration damping device according to the present invention is configured as described above and has durability, it is possible to take a permanent vibration damping measure. Further, since the outer shape is compact, it does not spoil the appearance even if it is installed on a highway, for example.

[Brief description of drawings]

FIG. 1 (a) is a perspective view of a dynamic vibration reducer in a vibration damping device according to an embodiment of the present invention, FIG. 1 (b) is a sectional view, and FIG. 1 (c) is a usage explanatory diagram.

FIG. 2 is a perspective view of a conventional vibration damping device.

[Explanation of symbols]

 1 cover 2 pendulum rod 3 heavy pyramid 4 reaction plate 5 universal joint 6 rubber 7 TV camera 8 TV camera column 9 dynamic vibration absorber 10 installation jig 11 highway 12 bridge girder 13 bridge pier

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshitsugu Nekomoto 2-1-1, Niihama, Arai-cho, Takasago-shi, Hyogo Mitsubishi Heavy Industries Ltd. Takasago Laboratory

Claims (1)

[Claims] 1. A pendulum rod having a weight cone attached to a lower end thereof and being hung from a universal joint and swinging in all horizontal directions, and the pendulum abutting on an outer periphery of the pendulum rod with an initial compression force. A vibration damping device, comprising: a rubber-like elastic body that adjusts the frequency of the rod and attenuates the vibration.