ROTATION DAMPER

摘要

A rotary damper is provided so that air incorporated into a housing during assembly is not excessively compressed, whereby a generation of a peculiar sound due to the air incorporated into the housing can be prevented even though the rotor rotates in both directions, and so that the air is stopped and captured in a fixed place whereby influence on the generated torque can be reduced, and irregularity of the torque can be reduced progressively. A rotary damper includes a housing (11, 51), silicon oil housed inside the housing (11, 51), a rotor 31 housed inside the housing (11, 51), and having a shaft member (32) projecting from the housing (11, 51) and having a resistance member (36) moving through the silicon oil (21) inside the housing (11, 51), and an 0-ring (61) for preventing leakage of the silicon oil (21) from between the shaft member (32) and the housing (51). A circumferential groove (54) is provided on an inner face of the housing (51) facing the resistance member (36).