| 摘要 |
PURPOSE:To promote the reduction of noise in a car room by providing a film member with a predetermined space in the bottom side of a roof panel and constituting a film vibration type resonator so as to vertically move the film member in a manner wherein a resonance frequency of the resonator obtains the frequency in accordance with an engine speed. CONSTITUTION:A roof interior material 2 is provided with a predetermined space in the bottom side of a roof panel 1 in an automobile, and between this interior material 2 and the roof panel 1, a film member 3, making its face to the roof panel 1 with a predetermined space, is provided. The film member 3 is constituted of a flat film extending frame 3b and a film main unit 3a of synthetic resin or the like adhesively attached to the total area in the upper surface of this frame 3b, and a film vibration type resonator 5 is constituted of this film member 3 and an air layer 4 between the film member 3 and the roof panel 1. This film member 3 is vertically moved by a hydraulic cylinder 6, provided in four corners of the film member, in a manner wherein a resonance frequency of the resonator 5 obtains the frequency in accordance with an engine speed, and a so-called confined noise is reduced. |
