Abstract: Provided is a shock absorber in which a check valve seated on a seat portion (second seat portion) having an annular shape is quickly opened during a reverse stroke. As a result, a working fluid in a chamber on a downstream side can be quickly introduced into a back-pressure chamber. Hence, a delay in response of a damping force, which may be caused by sticking of the check valve to a relief valve, can be suppressed.

Abstract: Provided is a shock absorber that is so designed that fail-down is prevented, which is caused when solenoid thrust is relatively small. The shock absorber comprises a chamber disposed on one side of a valve element and communicating with a cylinder's one side chamber and a cylinder's other side chamber, a first communication passage allowing the chamber and the cylinder's one side chamber to communicate with each other, and a second communication passage allowing the chamber and the cylinder's other side chamber to communicate with each other. The first communication passage includes a first orifice, and the second communication passage includes a second orifice.

Abstract: Provided is a shock absorber that is so designed that fail-down is prevented, which is caused when solenoid thrust is relatively small. The shock absorber comprises a chamber disposed on one side of a valve element and communicating with a cylinder's one side chamber and a cylinder's other side chamber, a first communication passage allowing the chamber and the cylinder's one side chamber to communicate with each other, and a second communication passage allowing the chamber and the cylinder's other side chamber to communicate with each other. The first communication passage includes a first orifice, and the second communication passage includes a second orifice.

Abstract: A stopper mechanism includes a second cylinder provided at an end portion in an inner cylinder, and a second piston configured to move along with movement of a piston rod to be capable of being fit-inserted through the second cylinder. The second piston includes a stopper coupled to the piston rod, a castle integrated with the stopper by plastic flow to form a ring groove on an outer periphery of the second piston between the castle and the stopper, and a piston ring fixed into a ring groove formed by the stopper and the castle so that the piston ring is displaceable in the ring groove in an axial direction and is retained in the ring groove, and has an annular shape with both ends in a circumferential direction which are formed by partially cutting the piston ring.

Abstract: A stopper mechanism includes a second cylinder provided at an end portion in an inner cylinder, and a second piston configured to move along with movement of a piston rod to be capable of being fit-inserted through the second cylinder. The second piston includes a stopper coupled to the piston rod, a castle integrated with the stopper by plastic flow to form a ring groove on an outer periphery of the second piston between the castle and the stopper, and a piston ring fixed into a ring groove formed by the stopper and the castle so that the piston ring is displaceable in the ring groove in an axial direction and is retained in the ring groove, and has an annular shape with both ends in a circumferential direction which are formed by partially cutting the piston ring.