Noise attenuator and vehicle air intake duct provided therewith

摘要

A noise attenuator which can reduce time and cost for installation thereof as compared with the conventional configuration and a vehicle air intake duct provided with the noise attenuator are provided. The noise attenuator includes a pair of circular through holes formed through a duct wall, a pair of wave transmitting/receiving membrane which are stretched so as to close the circular through holes, and a seesaw member which connects between central portions of the paired transmitting/receiving membranes. Accordingly, when one of the membranes receives a sound wave of noise thereby to be vibrated at a predetermined frequency, the other membrane follows it and is also vibrated while shifted by a half cycle. As a result, a cancellation wave with a phase opposite to the sound wave received by the one membrane is transmitted from the other membrane, whereupon the noise can be attenuated.

主权项

1. A vehicle air intake duct disposed along an air intake passage of an engine and provided with a noise attenuator which reduces noise transmitting in the duct, the noise attenuator comprising:
a pair of circular through holes formed through a duct wall; a pair of wave transmitting/receiving membranes which are stretched so as to close the respective circular through holes, receive a sound wave, and vibrate; a seesaw member which connects between central portions of the paired transmitting/receiving membranes and is pivotally supported with respect to the duct; and an inner limiting member that is opposed to an inner surface of a corresponding one of the wave transmitting/receiving membranes, with a gap being defined therebetween, the inner limiting member extending along the corresponding one of the wave transmitting/receiving membranes and being formed into a grid shape, a reticular shape, a bar shape or a beam shape.