JP2535576Y2 - Damping device - Google Patents

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 suitable for damping a superstructure of a ship or a land structure such as a building or a large steel structure.

[0002]

2. Description of the Related Art A dynamic vibration absorber has been known as one of vibration damping means for a structure. The basic configuration of the dynamic vibration absorber is as shown in FIG. 4, in which a vibrator 10 is supported on a support base 12 via a spring 11 and its natural frequency is
0 and the rigidity of the spring 11. When the natural frequency of the dynamic vibration reducer to match the frequency f _o of the structure by selecting a stiffness of the mass and the spring 11 of the vibrator 10 suitably, the structure by the action of the dynamic vibration reducer 3 Is changed from the characteristic shown by the solid line to the one shown by the broken line, and the vibration reduction effect is obtained.

Further, a vibration damping device used as a vibration damping measure for a ship uses water in a U-shaped communication tank as shown in FIG. The water in the tank moves in the direction of the arrow, and its natural period (natural frequency) is uniquely determined when the size of the tank is determined. Also in this case, the same vibration reduction effect as that of the dynamic vibration absorber can be obtained by matching the natural frequency of the vibration damping device with the frequency of the ship.

[0004]

The above-described dynamic vibration absorber has the following problems. (a) The amplitude of the vibrator increases, and there is a concern about the strength of the spring. (b) For large dynamic vibration absorbers, it is difficult to design and manufacture a spring mechanism. (c) To adjust the frequency, it is necessary to change the mass and spring rigidity of the vibrator.

On the other hand, in order to lower the natural frequency of the U-shaped communication tank, it is necessary to increase the size of the tank.

The present invention is based on a U-shaped communication tank which has the advantage of eliminating the disadvantages of the above-mentioned conventional vibration damping device and not using a spring, and has a low natural frequency without increasing the size. It is intended to provide.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and comprises a pair of rigid tanks, and a horizontal tank provided between the same pair of rigid tanks and communicating with the respective rigid tanks. A damping device comprising a U-shaped communication tank filled with liquid therein, comprising a partition wall for preventing direct communication between each of the rigid tanks and the horizontal tank; The present invention relates to a vibration damping device, wherein a lower part of a shaped tank and a lower part of the horizontal tank adjacent to the rigid tank are communicated via detours which are extended and communicated downward, respectively.

[0008]

In the case of a U-shaped communication tank, the natural frequency can be reduced by increasing the equivalent length between the liquid surfaces of the rigid tanks. In the present invention, without increasing the size of the main body of the U-shaped communication tank, an extended bypass is provided at the lower portion to substantially increase the equivalent length, thereby reducing the natural frequency. .

[0009]

FIG. 1 is a sectional view of an embodiment of the present invention. In the figure, 4a and 4b are rigid tanks respectively, 1 is a horizontal tank communicating with the rigid tanks, 2 is a liquid filled in the tanks, 13a and 13b are adjacent portions of the rigid tanks and the horizontal tank. The partition walls 3a and 3b are provided so as to prevent direct communication of the partition walls, and are detours provided to extend below the partition walls, and are communication portions that bypass the portions blocked by the partition walls. is there. 6a and 6b are air chambers above the rigid tank, 5a and 5b are communication pipes for communicating the air chambers, 5 is an air supply pipe for supplying air to the air chambers 6a and 6b and changing the air chamber pressure, Reference numeral 7 denotes a valve which shuts off the flow of the pipe 5. Reference numeral 9 denotes an air release valve for releasing residual air in the horizontal tank 1, and reference numeral 8 denotes a mounting base. L is the equivalent length of the distance between the liquid surfaces of both rigid tanks measured along the direction of liquid movement. This device constitutes a U-shaped communication tank as a whole.

When the valve 7 is open, the natural frequency f of the U-shaped communication tank is expressed by the following equation.

[0011]

(Equation 1)

G: gravitational acceleration L: equivalent length That is, if the equivalent length L is increased, the natural frequency can be reduced (the oscillation period is increased). In this embodiment, by providing a detour extending below the rigid tank,
Since the equivalent length can be increased, when the vertical and horizontal depth dimensions of the main body portion (excluding the bypass) of the conventional U-shaped communication tank are the same, the natural frequency is reduced as shown in FIG. (A large period). Therefore U
A vibration damping device having a low natural frequency can be provided without increasing the size of the main body of the character-shaped communication tank.

[0013]

[Effect of the Invention] The vibration damping device of the present invention has a partition wall for preventing direct communication between each rigid tank and the horizontal tank, and is provided at the lower part of each rigid tank and the same rigid tank. Provided is a vibration damping device having a low natural frequency without increasing the size of the U-shaped communication tank because the lower parts of the adjacent horizontal tanks are communicated with each other via a detour that is extended downward and communicated with each other. can do.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a comparison diagram of the effects of the above embodiment and a conventional U-shaped damping tank.

FIG. 3 is a diagram illustrating the operation of the dynamic vibration absorber.

FIG. 4 is a sectional view of a dynamic vibration absorber as a first example of a conventional vibration damping device.

FIG. 5 is a cross-sectional view of a U-shaped restriction tank as a second example of a conventional vibration damping device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Horizontal tank 2 Liquid 3a, 3b Detour 4a, 4b Rigid tank 5 Air supply piping 5a, 5b Communication piping 6a, 6b Air chamber 7 Valve 8 Installation stand 9 Air release valve 10 Vibrator 11 Spring 12 Support base 13a, 13b Partition wall

Claims (1)

(57) [Scope of request for utility model registration] 1. A tank having a pair of rigid tanks and a horizontal tank provided between the pair of rigid tanks and communicating with each of the rigid tanks, which is filled with liquid to form a U-shaped communicating tank. In the vibration damping device, a partition wall for preventing direct communication between each of the rigid tanks and the horizontal tank is provided, and a lower portion of each of the rigid tanks and a lower portion of the horizontal tank adjacent to the rigid tanks Are communicated via detours which extend downward and are communicated with each other.