Patent ID: 7204353

Claim:
A rotary damper comprising a fluid chamber which is formed in a casing and into which viscous fluid is charged, a vane which is disposed in said fluid chamber, a fluid passage formed in said vane or in a partition wall which partitions said fluid chamber, and a valve which automatically varies a flow rate of the viscous fluid passing through said fluid passage in correspondence with variation in load, said valve comprises a leaf spring including a to-be supported portion and a flow rate-adjusting portion, said to-be supported portion is supported by said vane or said partition wall, wherein said flow rate-adjusting portion is provided so as not to close the fluid passage when no load is applied, wherein said flow rate-adjusting portion bends so that its one surface side projects when no load is applied, wherein said flow rate-adjusting portion becomes deformed in a direction in which said fluid passage is closed when receiving pressure of the viscous fluid on its one surface side, wherein a flow rate of the viscous fluid passing through said fluid passage is adjusted depending on a degree of deformation of said flow rate-adjusting portion corresponding to magnitude of pressure of the viscous fluid applied to one surface side of said flow rate-adjusting portion, and wherein said flow rate-adjusting portion keeps said fluid passage open at all times while pressure of the viscous fluid is received on its other surface side.