| 摘要 |
PURPOSE:To eliminte noises generated to the outside of a car and filled in the car by vibrating a vibrating plate to generate sound having opposite site phase to that of pulsating sound of exhaust for silencing so that sound from extremely low frequency i.e. low order component of the rotational speed of an engine can be silenced. CONSTITUTION:In a portion 4a of an exhaust silencer 4 is generated sound having the same frequency and amplitude as exhaust sound from an engine and phase deviated by half a wave length from the exhaust sound(sound of opposite phase) to be combined with th exhaust sound for silencing. A variabl volume type resonace chamber 11 is provided on the opposite side to an expansion chamber 8 to sandwich the other partition plate 10 between itself and said expansion chamber 8 and communicated thereto through a communicating pipe 12. A bellows 13 consisting of aluminized spring copper or the like is secured fixedly at one end of the partition plate 10 side. A concave vibtating plate 14 is mounted on the other end of the bellows 13 to close the bellows. A device for vibrating the vibrating plate 14 is constituted of a field system 15, a coil 16, bobbins 17, 18, etc. |
