Patent ID: 7207425

Claim:
A rotary damper comprising: a housing, a viscous fluid filled in the housing, a rotor disposed in the housing and having a shaft part partially protruding from the housing and a resistance part provided on the shaft part for moving in the viscous fluid inside the housing, a seal member disposed between the shaft part and the housing for preventing leakage of the viscous fluid, a first sloping part provided on the resistance part at an upstream side in a rotational direction thereof and having a distance relative to an inner surface of the housing gradually decreasing toward a downstream side in the rotational direction, and a second sloping part provided on the resistance part at the downstream side in the rotational direction and having a distance relative to the inner surface of the housing gradually increasing toward the downstream side in the rotational direction; wherein said resistance part includes radial portions extending radially outwardly from the shaft part, and end portions provided on outer sides of the radial portions, each of said end portions having an outer surface facing an inner surface of the housing to form the first and second sloping parts, and upper and lower surfaces; and wherein each of said radial portions is a rectangular flat plate, and each of said end portions is an arc-shaped plate attached perpendicularly to an end of the rectangular flat plate and having a thickness less than that of the outer surface.