Patent ID: 6769520
Filing Date: 2004-08-03
Classification: F16F

Abstract:
A damper comprising:a rotatable shaft member having a shaft and wings formed on an outer periphery of the shaft; a cylindrical casing incorporating said shaft member; a plurality of oil chambers defined between the outer periphery of said shaft member and an inner periphery of said casing; at least one protrusion provided on the inner periphery of said casing, said at least one protrusion structured and arranged so that it is slides over an outer periphery of said shaft as said rotatable shaft member rotates; and at least one communication path having a first open end that communicates with one of said plurality of oil chambers and a second open end that communicates with another one of said plurality of oil chambers, said communication path passing through said shaft to enable communication between two adjacent oil chambers of said plurality of oil chambers, wherein said at least one protrusion is structured and arranged so that as said rotatable shaft member rotates said protrusions closes one of said first and second open ends of said communication path, within a relative-rotating range of said shaft member.