| 摘要 |
PROBLEM TO BE SOLVED: To reduce engine noise with a simple structure. SOLUTION: The sectional area variable structure is constituted such that a positive pressure chamber 60 and a negative pressure chamber 62 are partitioned by a diaphragm 58, and a shutter member 70 is connected to the diaphragm 58 so as to slide along with a movement of the diaphragm 58. An elastic member 80 which makes the shutter member 70 to be an air flow passage 44 side is arranged to the shutter member 70. A first through hole 64 for communication of the air flow passage 44 with the positive pressure chamber 60 is arranged, and a second through hole 66 for communication of the air flow passage 44 with the negative pressure chamber 62 is arranged to the shutter member 70. In response to an intake air amount of an engine, a projecting amount of the shutter member 70 to the air flow passage 44 is changed by a change of a balance relation between a pressure difference between the positive pressure chamber 60 and the negative pressure chamber 62, and an elastic force of the elastic member 80, thereby successively performing reversible change of a sectional area of the air flow passage 44. COPYRIGHT: (C)2005,JPO&NCIPI
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