| 摘要 |
PROBLEM TO BE SOLVED: To provide a sound absorber for attaining excellent sound absorbing effect in a low frequency region without increasing its size. SOLUTION: In the sound absorber 1 including a frame body 2 in which a through hole 2a is formed, and a film vibration type absorbing material 3 which covers one aperture of the through hole 2a, the film vibration type absorbing material 3 is composed of layered product in which a plurality of sound absorbing layers are united. In the plurality of sound absorbing layers, a sound absorbing layer with the highest storage elastic modulus is a first absorbing layer, and a sound absorbing layer with the lowest elastic modulus is a second absorbing layer. E'1/E'2≥3, where E'1 is the storage elastic modulus of the first sound absorbing layer, and E'2 is the storage elastic modulus of the second sound absorbing layer, and in the layered product, the storage elastic modulus of each sound absorbing layer is gradually decreased outwards from the first sound absorbing layer product. COPYRIGHT: (C)2009,JPO&INPIT
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