Rotary damper

Abstract

This invention is intended to provide a semi-active rotary damper that can obtain a large breaking force to disperse a large torque. The rotary damper 100 comprises a damping shaft 111 to be connected to a rotating shaft, and a closed hollow cylindrical housing 113 surrounding the damping shaft 111. A first fluid chamber 116A and a second fluid chamber 116B are formed between an outer face of the damping shaft 111 and an inner face of the housing 113 by a partition 115 and a wing 112. The first fluid chamber 116A and the second fluid chamber 116B are filled with magnetorheological fluid. Meanwhile, an annular solenoid 114 fixed to the housing 113 forms a portion of a flow path 126, 125 and 127 between the first fluid chamber 116A and the second fluid chamber 116B. When switching on the electric current through the coil 122, the annular body 121 is magnetized