Rotating damper

A rotary damper including a casing (2) having a receiving hole (23), a rotor fitted to said receiving hole (23) such that said rotor is non-movable in an axial direction thereof but rotatable, a piston (4) inserted into said receiving hole (23) between said rotor (3) and a bottom portion (22) of said receiving hole (23) such that said piston (4) is movable in the axial direction thereof but non-rotatable, and for defining the inside of said receiving hole (23) into a first chamber (R1) on said bottom portion (22) side and a second chamber (R2) on said rotor (3) side, and viscous fluid filled in said first and second chambers (R1, R2), a cam mechanism (7) for allowing movement of said piston (4) from said second chamber (R2) side to said first chamber (R1) side when said rotor (3) is rotated in one direction and for allowing movement from said first chamber (R1) side to said second chamber (R2) side when said rotor (3) is rotated in the other direction being disposed between said rotor (3) and said piston (4),

• wherein a cam member (5) is disposed within said first chamber (R1) such that said cam member (5) is non-movable in the axial direction of said receiving hole (23) but rotatable, said cam member (5) is non-rotatably connected to said rotor (3), a second cam mechanism (10) for allowing movement of said piston (4) from said second chamber (R2) side to said first chamber (R1) side by said cam mechanism (7) when said rotor (3) is rotated in one direction and for allowing movement of said piston (4) from said first chamber (R1) side to said second chamber (R2) side when said rotor (3) is rotated in the other direction is disposed between said rotor (3) and said piston (4), and amounts of movement of said piston (4) corresponding to rotation of said rotor (3) by said second cam mechanism (10) and said cam mechanism (7) are set to be equal.