JPH03140648A - Vibration damping device for structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to improvements in vibration damping devices that suppress vibrations in buildings and the like.

(Prior Art) As a vibration damping device for suppressing vibrations of a building, etc., a movable mass 1 is suspended from a structure 2 via an arm 3 in a pendulum shape as shown in FIG. A vibration damping device in which an actuator or damper 11 for suppressing rocking is interposed between a structure 2 and a movable mass 1 is known.

(Problem to be solved by the invention) In order to obtain a good vibration damping effect with such a vibration damping device,
It is necessary to set the period of the natural vibration of the movable mass 1 close to the period of the natural vibration of the structure to be damped.

Adjustment of the natural period for this purpose was done by changing the length l of the arm 3, or by interposing a spring 12 horizontally between the movable mass 1 and the structure 2, as shown in Figure 5. .

At that point, the natural angular frequency of the pendulum of movable mass 1 is 4. teeth, W. = 5 houses in F-cho ■ ``10,000 However, I? :Gravity acceleration N: Spring constant of spring 12 ■Mass of two movable mass 1 e; Length of arm 3 Also, the natural period T is It is expressed as T=2π/l110.

As is clear from these equations, the natural period T is large relative to the mass of the movable mass 1, that is, the natural frequency is 4. If you want to make p smaller, it is necessary to make p larger, and if you insert the spring 12, the natural angular frequency will increase. On the contrary, it becomes larger.

However, when the length p of the arm 3 is increased, there is a problem in that the vibration damping device becomes larger.

The present invention aims to solve the above problem 7α by providing a vibration damping device that can adjust the natural period without changing the hanging length of the movable mass.

(Means for Achieving the Object) For this purpose, the present invention suspends a movable mass on a structure via an arm so that it can swing freely, and connects an actuator or damper that suppresses the swinging of the movable mass to the structure. In a vibration damping device for a structure interposed substantially horizontally between the movable mass and the structure, a spring is interposed vertically between the movable mass and the structure.

(Function) When the movable mass swings, the spring expands, and a horizontal force based on its own weight and a horizontal force based on the spring load act on the movable mass. In this case, the direction of the horizontal force based on the spring load differs depending on the direction of action of the spring load. Therefore, with this setting, the natural period of the movable mass changes, and a preferable natural period can be obtained without changing the length of the arm suspending the movable mass.

Further, by interposing the spring in the vertical direction, it is possible to cope with any horizontal displacement of the movable mass with one spring.

(Example) Embodiments of the present invention are shown in FIGS. 1 to 3.

In FIG. 1, reference numeral 1 denotes a movable mass having a mass m, which is suspended from a structure 2 via two parallel arms 3 so as to be able to swing freely.

An actuator or damper (not shown) is horizontally interposed between the movable mass 1 and the structure 2 in order to suppress relative displacement in the horizontal direction.

Further, a bracket 4 is formed at the center of the upper surface of the movable mass 1, and a gas spring 6 is interposed between it and a similar bracket 5 formed on the structure 2 above.

This gas spring 6 has a piston rod 9 coupled to a piston 8 which is slidably housed in a sill 7 so that the piston rod 9 protrudes freely in the axial direction. The bracket 51 is connected to the bracket 51 so that it can rotate freely.An accumulator 10 is connected to the cylinder 7, and the piston rod 9 is caused by the accumulation of pressure in the accumulator 10.
is always biased in the direction of expansion.

Next, the action will be explained.

When the movable mass 1 swings as shown in the figure, a horizontal force in the direction of the neutral position due to the movable mass 1's own weight acts on the movable mass 1. On the other hand, the gas spring 6 biased in the direction of extension exerts a horizontal force on the movable mass 1 in the opposite direction.

In this case, if the horizontal displacement of the movable mass 1 is χ, the horizontal force F that attempts to return the movable mass 1 to the neutral position is F = l (m・y f)・Z #11 (f ・X
#2)=-III[(y#+)+ ((1,-12)
・fl/(Nl・12・l11)]・χ However, f: Spring load (upward direction is positive) 11: Length 12 of arm 3 ・Length 1n of gas spring 6: Mass of movable mass 1 Natural angular frequency range. wo = ≦? , + 2+
-22) ・[1/(1,・12 ・“inside”).

Here, since L>12 and the piston rod 9 is biased 11 times in the direction of extension, the spring load is ``0''. Therefore, the natural angular frequency 1° is smaller than when the gas spring 6 is not interposed. The natural period T becomes larger.

On the other hand, when >0, that is, when the piston rod 7 is biased by 1·[ in the contraction direction, the natural period T becomes smaller than when the gas spring 6 is not interposed.

In this way, by setting the spring load of the gas spring 6, the fixed period T of the movable mass 1 can be arbitrarily set without changing the length 11 of the arm 3.

In addition, since the gas spring 6 is interposed vertically between the movable mass 1 and the structure 2, it is effective not only when the movable mass 1 is displaced in the direction shown in Fig. 1 but also in a direction perpendicular to this direction. It acts on In addition, since the spring 6 is installed in the opening of the arm 3, it does not take up much space, and as shown in FIG. There's no fear of it happening.

FIG. 3 shows another embodiment of the invention, in which:
A spring 6 is interposed between the movable mass 1 and the lower structure 2. If the lower part of the movable mass 1 is empty, such an arrangement may be used.

(Effects of the Invention) As described above, the present invention interposes a spring in the vertical direction between the movable mass suspended from the structure and the structure, so the length of the arm for suspending the movable mass remains unchanged. Furthermore, the natural period of the vibration damping device can be set longer by setting the spring load. Furthermore, displacement of the movable mass in any horizontal direction can be handled with one spring. Therefore, there is a great effect in downsizing the vibration damping device.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of a vibration damping device showing an embodiment of the present invention;
FIG. 2 is a schematic side view of the vibration damping device showing the positional relationship between the actuator or damper and the spring, and FIG. 3 is a schematic side view of the vibration damping device showing another embodiment. Also. FIGS. 4 and 5 are schematic side views of a vibration damping device illustrating a conventional example. 1... Movable mass, 2... Structure, 3... Arm,
6... Spring.

Claims (1)

[Claims] In a vibration damping device for a structure, a movable mass is suspended from the structure via an arm so as to swing freely, and an actuator or damper for suppressing the swing of the movable mass is interposed approximately horizontally between the movable mass and the structure, A vibration damping device for a structure, characterized in that a spring is interposed vertically between a movable mass and the structure.