| 摘要 |
PROBLEM TO BE SOLVED: To attenuate vibration over a wide range of vibration by forming a diaphragm member in such a way that the diaphragm can move and attenuate vibration other than vibration related to the length of an acoustic tuner by force of sound wave traveling in the tuner. SOLUTION: A 1/4 wave length acoustic tuner 12 has a tubular body 14 extending from an inlet air duct 10 radially outward, and the body 14 terminates at a second end part 18. Then, when a sound wave is passed through the body 14 to collide with a diaphragm 20 of the second end part 18, the pressure generated at the second end part 18 moves the diaphragm 20 outward to convert a part of sound energy into mechanical energy. Similarly, when the sound wave is reflected to return to a first end part 16, the diaphragm 20 is tensed inward to consume the sound energy as mechanical energy. By the inside and outside motion of the diaphragm 20, the sound energy is converted into mechanical energy, and thus the width of acoustic vibration frequency after the attenuation by an ordinary 1/4 wave length acoustic tuner can be enlarged.
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