| 摘要 |
PURPOSE:To simplify the construction and reduce the noise by a method wherein dynamic vibration absorbers are attached to the positions at least near the corners of a frame-shape heavy weight body and the vibration of the heavy weight body is suppressed effectively. CONSTITUTION:Dynamic vibration absorbers 11, composed of springs 12 and dynamic vibration absorbing weights 13 fixed to the springs 12, are attached to a plurality of positions, including the position near each corner, of a square frame-shape heavy weight body 6. The vibration is transmitted from reinforcing stays 3 to the heavy weight body 6 through thin plates 4 and soundproof plates 5 and further transmitted to the dynamic vibration absorbing weights 13 through the springs 12 of the dynamic vibration absorbers 11 and makes the weights 13 vibrate. When the resonance condition is realized by making the characteristic frequency of the dynamic vibration absorber 11 identical to the frequency of the heavy weight body 6, the reversal force of the same amplitude as, and the opposite phase to, the vibration of the heavy weight body 6 is applied to it so that the vibration at the fitting points of the heavy weight body 6 is suppressed significantly. With this constitution, the construction is simplified and the noise is reduced. |
