Patent ID: 7334663

Claim:
A variable resonator comprising: a communicating pipe disposed on an outer periphery of an air intake pipe constituting an air intake passage of an engine, said communicating pipe having a conduit formed in an internal portion thereof so as to lie alongside an outer peripheral wall surface of said air intake pipe; a resonance chamber mounted to said communicating pipe so as to communicate with a first end of said conduit; a first communicating aperture disposed through said air intake pipe so as to communicate between said air intake passage and said conduit such that a plurality of said first communicating apertures are arranged in a single row in a conduit direction of said communicating pipe or such that said first communicating aperture extends in said conduit direction; and a movable member formed so as to have a tubular body having a movable passage extending from a second communicating aperture formed on a side wall to a first end opening, said movable member being disposed such that said side wall on which said second communicating aperture is formed faces said air intake pipe, such that said first end opening faces said first end of said conduit, and so as to be movable through said conduit in said conduit direction by sliding in contact with an inner wall surface of said communicating pipe, wherein: a communicating channel length between said air intake passage and said resonance chamber is adjusted by changing a position of overlap of said second communicating aperture relative to said first communicating aperture by moving said movable member in said conduit direction so as to change a communicating position between said air intake passage and said movable passage in said conduit direction by means of said first communicating aperture and said second communicating aperture.