JPH04157233A - Dynamic vibration damper - Google Patents

Abstract

PURPOSE:To adjust a frequency of a weight with a compact constitution by changing damping force of a damping means connected to the weight capable of moving along tracks. CONSTITUTION:A movable mass 16 is provided with four wheels 19 rolling on tracks 14, 15, and a recess portion 16b having a shaft 20 spanned in the center at the bottom thereof. The upper end 17a of a damper 17 and the upper end 18a of a spring 18 are rotatably fitted to the shaft 20 via a bearing 21, respectively. The lower end 17b of the damper 17 and the lower end 18b of the spring 18 are rotatably fitted to another shaft 23 spanned between the supporting portions 22a, 22b of a fixing member 22 through other bearing 24, respectively. The damper 17 and the coil spring 18 are provided in parallel between the movable mass 16 and the fixing member 22. A change in damping force (a spring constant, a damping ratio or the like) of a damping means enables vibration to be effectively damped according to a vibration frequency of a vibrator.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a dynamic vibration absorber, and more particularly to a dynamic vibration absorber configured to correspond to the vibration frequency of a vibrating body.

BACKGROUND OF THE INVENTION As construction technology for high-rise buildings progresses, technological development to prevent high-rise buildings from shaking due to earthquakes and the like is progressing. As a means of achieving this, dynamic vibration absorbers designed to suppress vibrations in high-rise buildings are being developed.

As a conventional dynamic vibration absorber, there is a device as shown in FIG. The dynamic vibration absorber shown in Fig. 8 has an arm 2 mounted on a gate-shaped support 1.
is suspended rotatably, and a weight 3 is attached to the end of the arm 2. This dynamic vibration absorber is installed, for example, on the roof of a high-rise building, and when the high-rise building vibrates, the arm 2 and weight 3 swing about a shaft 4 like a "pendulum." Then, the frequency of this pendulum 3 is adjusted so as to correspond to the frequency of the high-rise building.

In this case, the frequency of the pendulum can be adjusted by changing the length of the arm 2.

Problems to be Solved by the Invention However, in the above-mentioned conventional dynamic vibration absorber, the frequency is reduced (
If an attempt is made to lengthen the cycle, the arm 2 must be made longer, which increases the size of the entire device. In addition, in order to prevent arm 2 from becoming long,
As in Publication No. 39, a pendulum with a folded hanging string has been developed, or the structure has become more complicated. In addition, in conventional dynamic vibration absorbers, when increasing the frequency (shortening the period), the arm 2 becomes considerably short, and when one rod is used, the length of the arm 2 is 24.8 an, which means that the weight weighs several tons. It becomes structurally impossible to support the weight 3, and there is a problem that it is difficult to adjust the frequency of the weight 3 according to the frequency of the high-rise building.

Therefore, an object of the present invention is to provide a dynamic vibration absorber that solves the above problems.

Means for Solving the Problems The present invention provides: a track provided above a vibrating body and extending in the vibration direction of the vibrating body; and a track movably provided on the track, the vibrating body a weight set to have a mass that damps vibrations of the weight, one end of which is hooked to the weight, and the other end of which is supported by a fixed part located vertically downward perpendicular to the orbit;
A damping means includes a spring and a damper that dampens the movement of the weight while swinging about the fixed part as a fulcrum.

By changing the damping force of the damping means connected to the weight moving along the action trajectory, the frequency of the weight can be adjusted as appropriate, and the structure is compact.

Embodiment FIGS. 1 and 2 show a first embodiment of a dynamic vibration absorber according to the present invention.

In both figures, the dynamic vibration absorber 11 has a base 13 fixed to the roof 12 of the building, and a track 14 provided at the upper end of the base 13.
．． 15, a movable mass (weight) 16 that moves on the track 14.15, and a damper 17 that buffers the movement of the movable mass 16.
, a coil spring 18 (buffer means). base 13
A bottom portion 13a is fixed to the rooftop 12 by bolts 13d, and a pair of walls 13b and 13c that stand parallel to each other are provided on the upper surface of the bottom portion 13a. This pair of walls 1
3b, 13c have the aforementioned track 14.15 at their upper end.

The movable mass 16 has a considerable weight depending on the size and mass of the building, for example, on the order of several tons.

The mobile mass 16 has four wheels 19 rolling on tracks 14.15 in order to move in the X direction in response to the vibrations of the building. Each wheel 19 has a flange 19a on its inner end surface for preventing wheel slippage, and is rotatably supported by a shaft 16a protruding from the side surface of the movable mass 16. Therefore, the movable mass 16
Although it has a considerable weight, it can be moved in the direction of extension of the track 14.15 (X direction) with a low load by shifting the wheels 19.

Further, a recess 16b is formed at the center of the bottom of the movable mass 16, and the shaft 20 is horizontally suspended therein. A damper 17 is attached to this shaft 20.
The upper end 17a and the upper end 18a of the spring 18 are rotatably fitted together via a bearing 21.

A fixing member 22 is located at an intermediate position of the upper base 13 in the X direction, and is fixed to the upper surface of the bottom 13a between the pair of walls 13b and 13c. This fixing member 22 has a pair of support parts 22a and 22b that stand upright.
A shaft 23 is horizontally suspended between a and 22b. This shaft 23
is provided at a vertically downward position perpendicular to the track 14.degree. Furthermore, since the damper 17 and the coil spring 18 are mounted in parallel between the movable mass 16 and the fixed member 22,
The entire device has a compact configuration.

Normally (when the building is not vibrating), the movable mass 16 is stopped at the neutral position shown by the solid line in FIG. This is because the distance between the fixed shaft 23 and the movable shaft 21 is the shortest, and the tensile force of the spring 18 acts in the vertical direction perpendicular to the direction of movement (X direction), moving the movable mass 16. This is because the moment in the X direction to be caused becomes zero.

When a building (not shown) vibrates due to an earthquake or the like, the dynamic vibration absorber 11 installed on the building rooftop 12
The inertial force of the vibration acts on the movable mass 16, so that the movable mass 16 moves in the X direction along the trajectory 14.15. Then, the movable mass 16 moves in the X direction from the neutral position shown by the solid line in FIG. 1, and the damper 17 and spring 18 swing about the fixed shaft 23 as a fulcrum. As a result, the resistance force of the damper 17 and the tensile force of the spring 18 increase, and the speed of the movable mass 16 is reduced. And the movable mass I6 is
When it moves to the end position shown by the one-dot chain line or the two-dot chain line in FIG. 1, it returns to the neutral position by the tension of the spring 18. In the dynamic vibration absorber 11, the damping ratio of the damper 17 and the spring constant of the spring 18 are set in advance so as to match the frequency of the movable mass 16 or the vibration frequency of the building.

Therefore, even if the building vibrates, the movable mass 16 reciprocates in a direction opposite to the direction of vibration of the building (X direction), suppressing the vibration of the building. In addition, in the dynamic vibration absorber 11 having the above configuration, the damping ratio of the damper 17 and the spring constant of the spring 8 can be changed depending on the size of the building, etc., so the movable mass 16 can be adjusted according to the natural frequency of the building. It can be set to oscillate depending on the frequency. Therefore, even for relatively low frequency vibrations, the entire device does not have to be enlarged as in the conventional case, and the structure is compact.

A second embodiment of the present invention is shown in FIGS. 3 and 4.

Note that the same parts as in the first embodiment are given the same reference numerals and their explanations will be omitted.

In both figures, the upper surfaces of a pair of walls 13b' and 13c' standing up on the bottom 13a' of the base 13' are curved in an arc shape. Therefore, wall 13b'.

The tracks 25 and 26 provided on the upper surface of 130' are formed in an arcuate shape that is at an intermediate position in the X direction, that is, at the neutral position in the vertical direction of the fixed member 22, or at its lowest position, and rises as it moves in the X direction. .

Therefore, the movable mass 16 moves in the X direction due to the vibration of the building and rises along the arcuate trajectory 25,26. When the movable mass 16 moves to the end of the track 25.26, since the track 25.26 is inclined, it returns to the neutral position at a low position due to its own weight. Also, movable mass 1
6 rises as it moves to the end of the orbit 25° 26, the distance between the movable shaft 20 and the fixed shaft 23 increases, and the tensile force of the spring 18 increases accordingly. . Therefore, the return speed of the movable mass 16 is improved by increasing the tensile force of the spring 18, and the movable mass 16 can cope with high-frequency vibrations.

A third embodiment of the present invention is shown in FIGS. 5 to 7.

In each figure, the movable mass 16 has a support base 32 that supports a motor 31, and an output shaft 31a of the motor 31 is provided with a pinion 33. Wall f3 of support base 13
At the top of c there is a rack 3 extending parallel to the track 14.15.
4 is fixed.

A pinion 33 that is rotationally driven by a motor 31 is engaged with this rack 34 .

The motor 31 rotates the pinion 33 in response to a drive signal from a control circuit (not shown) when an earthquake occurs.

Therefore, the movable mass 16 is actively moved in the X direction by the rotational driving force of the motor 31, and damps the vibrations of the building.

In the above embodiment, the damper 17 and the coil spring 18 as a buffer means are provided in parallel, but the present invention is not limited to this. For example, a buffer means in which a spring is built inside the damper 17 may be used.

Effects of the Invention As described above, in the dynamic vibration absorber of the present invention, the weight moving on the orbit reciprocates in the vibration direction without being damped by the damping means that swings around the fixed part side as a fulcrum. By changing the buffering force (spring constant, damping ratio, etc.), vibration can be effectively damped in accordance with the vibration frequency of the vibrating body. Moreover, since the movement of the weight can be damped by a single damping means, the apparatus has the advantage of being compact in structure and requiring only a small installation space.

[Brief explanation of the drawing]

FIG. 1 is a front vertical cross-sectional view of a first embodiment of the dynamic vibration absorber according to the present invention, FIG. 2 is a vertical cross-sectional view taken along the solid line ■ in FIG. 1, and FIG.
The figure is a front vertical sectional view of the second embodiment of the present invention, and FIG.
5 is a front longitudinal sectional view of the third embodiment of the present invention, and FIG. 6 is a longitudinal sectional view taken along line IV-IV in FIG.
FIG. 7 is a longitudinal sectional view taken along the line ``--'' in FIG. 5, and FIG. 8 is a diagram for explaining a conventional dynamic vibration absorber. 11... Dynamic vibration absorber, 13... Base, 14.15° 25.26... Orbit, 16... Movable mass, 17...
・Damper, 18...Coil spring, 19...Wheel, 2
2...Fixing member, 31...Motor, 33...Pinion, 34...Rack. Patent applicant: Tokiko Co., Ltd. Figure 2 Figure 3 Figure 4 Figure 8

Claims (1)

[Scope of Claims] A track provided above a vibrating body and extending in the vibration direction of the vibrating body, and a track movably provided on the track to damp vibrations of the vibrating body. one end is hooked to the weight and the other end is supported by a fixed part located vertically downward perpendicular to the orbit, and the weight is oscillated about the fixed part as a fulcrum. 1. A dynamic vibration reducer comprising: a damping means comprising a spring and a damper to dampen the movement of the vibration absorber;