JPH03113143A - Vibration suppressing device for structure - Google Patents

Abstract

PURPOSE:To obtain a small-sized controller by assembling an inverted pendulum with a suspended pendulum by a movable mass. CONSTITUTION:A movable mass 1 is suspended in free oscillation through two parallel arms 3 from a structure 2. At the center of the movable mass 1, a through hole 4 is formed in the vertical direction and the inside of universal joint 5 held at the upper edge of the through hole 4 is allowed to penetrate in free slide in the axial direction through a bearing. The lower edge of the arm 6 is joined in free revolution with the structure 2, and a mass 7 having a mass M2 is joined at the upper edge of the arm 6. When the movable mass 1 swings, the arm 6 sides in the axial direction through the relative revolution with the movable mass 1 through the universal joint 5, and the mass 7 as inverted pendulum swings in the equal phase for a suspended pendulum by the movable mass 1.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to improvements in vibration damping devices for buildings, etc.

(Prior Art) As a vibration damping device for suppressing vibrations of a building, etc., as shown in FIG. A vibration damping device in which an actuator or damper 10 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.

The period T of the pendulum of the movable mass 1 is: T=2πf C7i where g: gravitational acceleration. If the natural period of the structure to be damped is long, it is necessary to set the period T of the movable mass 1 to be long, but as is clear from this equation, this requires the suspension length l of the movable mass 1 had to be made longer, resulting in the problem of an increase in the size of the vibration damping device.

SUMMARY OF THE INVENTION In order to solve the above problems, it is an object of the present invention to provide a vibration damping device in which the natural period of a pendulum can be adjusted without changing the hanging length of a movable mass.

(Means for Achieving the Object) To this end, the present invention provides vibration damping for a structure in which an actuator or a damper for suppressing the swinging of a movable mass suspended from the structure is interposed between the movable mass and the structure. In the device, an arm whose lower end is rotatably connected to a structure is allowed to freely rotate and slide through a bearing provided on the movable mass, and a mass having a predetermined mass is connected to the upper end of the arm. There is.

(Function) When the movable mass swings, the arm slides while rotating relatively, and the mass connected to the upper end of the arm swings as an inverted pendulum with the lower end of the arm as a fulcrum. In this way, by combining an inverted pendulum with a pendulum suspended from a movable mass, the natural period of the pendulum is determined not only by the hanging length of the movable mass, but also by the mass of the mass of the inverted pendulum and the length of the arm. It also changes depending on factors on the inverted pendulum side, such as the height. Therefore, by appropriately setting these elements, a preferable natural period can be obtained without increasing the hanging length of the movable mass.

(Example) Embodiments of the present invention are shown in FIGS. 1 and 2.

In FIG. 1, 1 is a movable mass having a mass M1, which is suspended from a structure 2 via two parallel arms 3 so as to be freely swingable.

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.

In addition, a through hole 4 is formed vertically in the center of the movable mass 1, and an arm 6 freely slides in the axial direction through a bearing inside a universal joint 5 held at the upper end of the through hole 4. do. The lower end of the arm 6 is rotatably connected to the structure 2, and the upper end of the arm 6 is connected to a mass 7 having a mass M2.

Next, the action will be explained.

When the movable mass 1 swings as shown in FIG.
The mass 7 slides in the axial direction while rotating relative to the movable mass 1 via the universal joint 5, and the mass 7 swings in the same phase as the pendulum suspended by the movable mass 1 as an inverted pendulum.

At this time, if the force in the χ direction exerted by gravity on the movable mass 1 is Fl, then P H = M l' g-Lallθ≠-M, ・g・
θ Technique - Ml・g・(χ/p,)...(1) However, θ, (1).

Furthermore, if the force in the χ direction that mass 7 exerts on movable mass 1 is F2, then F 2 = (1:l/Nz) ・ M z
・El ・tanθ 2 Iwa (ls/lz)・M2
・2・θ2″−1(fi/N2) ・M2 ・2・kuχ/
! 2) = (j!3#22)・M2・2・χ = (*/ lx') ・M 2 ・2 ・
χ ・ ・ ・ 2) However, θ2 < 1, k-13/12.

These resultant force F is given by (1)+(2) as F = −(
(M 1 ・ 9/e1) - k ・ M 2 ・ g
/12)) ・χ・ (3) From equation (3), the equivalent spring constant K can be obtained. That is, K-(M,・y/ 1-)<k-M 2・y/N2)
...(4) On the other hand, the equivalent mass M2' of M2 is M2 = (ly"/12'>・M2=2・M2
The equivalent mass M as a whole is M=Ml+M2=VB+k''·M2.

Therefore, the natural period T of vibration of this system is ■・2πF
D7te・2π 1+ 2・L)/f(M+−g/l+>Ak
-M2・g/ 12))・(5)

Here, assuming that the values M and e regarding the hanging pendulum are fixed, equation (5) becomes T=2π, ÷
・M2C21! , N22)・M2・g)・(5)′ However, CI+C2 can be rewritten as a constant. From this equation (5)', it is clear that if 13 and M2 are set large and 12 is set small, the natural period T becomes large.

Therefore, by setting the length of the arm 6 and the mass of the mass 7, the fixed period T can be arbitrarily set according to the fixed period of the structure 2 without changing the length 11 of the arm 3 of the movable mass 1. , a damping device with a long fixed period T can be configured compactly.

(Effects of the Invention) As described above, since the present invention combines an inverted pendulum with a pendulum suspended by a movable mass, control can be controlled by the settings on the inverted pendulum side without changing the length of the arm suspending the movable mass. The natural period of the vibration device can be set to be long. Therefore, even a vibration damping device that requires a long natural period can be configured compactly, which is highly effective in reducing the size of the vibration damping device.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical sectional view of a vibration damping device showing an embodiment of the present invention, and FIG. 2 is a schematic diagram illustrating a displacement state of the vibration damping device. Moreover, FIG. 3 is a schematic side view of a vibration damping device showing a conventional example. 1... Movable mass, 2... Structure, 3, 6... Arm, 5... Universal joint, 7... Mass.

Claims (1)

[Claims] In a vibration damping device for a structure in which an actuator or a damper for suppressing the swing of a movable mass suspended from the structure is interposed between the movable mass and the structure, an arm whose lower end is rotatably connected to the structure is connected to the structure. A vibration damping device for a structure, characterized in that a bearing part provided on a movable mass is freely rotated and slidably passed through the arm, and a mass having a predetermined mass is coupled to the upper end of the arm.