A shock absorber includes a cylinder sealed with a working oil liquid, a piston slidably fitted in the cylinder, a piston rod connected to the piston and extended to the outside of the cylinder, and a plurality of passages through which the working oil liquid flows due to the sliding of pistons therein, and a damping force generating mechanism that is provided in a part of the passages and suppresses the flow of the working oil liquid to generate a damping force. The damping force generating mechanism includes a valve body through which the passage penetrates, an annular seat that projects from the valve body and surrounds the passage, and a disc that can be seated on the seat. A contact width at which the disc and the seat come into contact with each other is different depending on a position in the circumferential direction. As a result, it is possible to obtain a shock absorber capable of suppressing a sudden change in damping force before and after the opening of the disc valve without having a complicated structure.

A damping force generating mechanism includes: a flow passage formation part that forms a flow passage through which a liquid flows; a valve configured to control a flow of the liquid in the flow passage; a back pressure control valve configured to control a pressure in a back pressure chamber that provides a back pressure to the valve by inflow of the liquid; and an accommodation part that is in a tubular shape with one side opening end narrower than another side opening end, forms the back pressure chamber, and accommodates at least the valve and the back pressure control valve.

A damper including inner and outer tubes and a control valve. A piston is slidably disposed within the inner tube to define first and second working chambers. An intermediate member assembly is disposed annularly about the inner tube. An intermediate channel is positioned radially between the intermediate member assembly and the inner tube and a reservoir channel is positioned radially between the intermediate member assembly and the outer tube. A first unidirectional blocking valve forms a first partition between first and second intermediate channel portions of the intermediate channel. A second unidirectional blocking valve forms a second partition between the second intermediate channel portion and a third intermediate channel portion. An external control valve has a control valve inlet that is arranged in fluid communication with the second intermediate channel portion.

A damping force generating mechanism includes: a flow passage formation part that forms a flow passage through which a liquid flows; and a valve that is configured to control a flow of the liquid in the flow passage. The flow passage formation part includes a first seat part that is provided radially outward of a flow passage port of the flow passage, protrudes from the flow passage port and contacts the valve, a second seat part that is provided radially outward of the first seat part, protrudes from the flow passage port and contacts the valve, and a circulation part having an orifice that allows the liquid to flow from the flow passage port toward the second seat part in a state in which the valve is in contact with the first seat part.

A shock absorber includes a suction passage permitting flow only from a reservoir toward a compression-side chamber, a rectification passage permitting flow only from the compression-side chamber toward an extension-side chamber, and a variable valve permitting flow only from the extension-side chamber toward the reservoir. A large chamber as a compression-side pressure chamber communicating with the compression-side chamber and an outer periphery chamber as an extension-side pressure chamber communicating with the extension-side chamber are partitioned in the shock absorber by a free piston that moves slidably within a bottom member serving as a housing. A compression-side pressure-receiving area of the free piston is larger than an extension-side pressure-receiving area. Therefore, even in the uniflow shock absorber with the extension-side chamber and the compression-side chamber at equal pressures during the contraction operation, the damping force is reduced under conditions in which high frequency is input since the free piston moves downward.

A shock absorber includes at least one of an expansion-side sensitive unit and a contraction-side sensitive unit. The expansion-side sensitive unit has an expansion-side actuating chamber that communicates with an expansion-side chamber and a contraction-side chamber, an expansion-side free piston that partitions the expansion-side actuating chamber into a first expansion-side pressure chamber and a second expansion-side pressure chamber, and an expansion-side spring element configured to bias the expansion-side free piston to compress the first expansion-side pressure chamber. The contraction-side sensitive unit has a contraction-side actuating chamber that communicates with a contraction-side chamber and a reservoir, a contraction-side free piston that partitions the contraction-side actuating chamber into a first contraction-side pressure chamber and a second contraction-side pressure chamber, and a contraction-side spring element configured to bias the contraction-side free piston to compress the first contraction-side pressure chamber.

An object is to provide a cylinder device which can be used successfully over a long period of time. The cylinder device includes a cylinder, a piston, an external cylinder, a tank and first piping. The piston is slidably inserted into the cylinder. The piston divides an interior of the cylinder into a rod-side chamber and a piston-side chamber. The external cylinder is disposed outside the cylinder and covers the cylinder. The tank is formed in a space between the cylinder and the external cylinder and stores an operating fluid. The first piping constitutes part of a first passage through which passes the operating fluid supplied to and discharged from the rod-side chamber or the piston-side chamber. The first piping has two ends one of which has a larger outer diameter than the other end. The first piping is disposed in the tank.

A door component has a controllable damping device and contains a magnetorheological fluid. Two connection units are movable relative to one another. One of the two connection units is connected to a support structure and the other one to a pivotable door unit. The device damps a movement of the door unit between a closed position and an open position in a controlled manner by way of a control unit. The magnetorheological damping device has a piston unit and a cylinder unit surrounding the piston unit. The piston unit divides a cylinder volume into two chambers. The piston unit is equipped with a first one-way valve. The two chambers are connected together, via an external return channel equipped with at least one controllable magnetorheological damping valve, to form a one-way circuit. When the piston unit moves in and out, the magnetorheological fluid flows through the piston unit in the same flow direction.

A damping valve includes a main valve opening and closing a main passage, and a pilot passage reducing a pressure of the upstream of the main passage by a throttle to guide as a back-pressure biasing the main valve to the closing direction. A pressure control valve being disposed on the downstream of the throttle and including a seating portion controlling the back-pressure, and a switching valve including a circular depressed portion opening and closing the pilot passage are integrated and controlled by a single solenoid. The damping valve includes fail passages being branched from the downstream of the throttle to bypass the main valve, and a fail valve opening and closing the fail passage. The switching valve is arranged on the upstream of the pressure control valve in the pilot passage. The fail passages are branched from the upstream of the switching valve of the pilot passage.

A continuously variable damper is disclosed. The damper includes an elongate outer tube and inner tube with a piston in the inner tube. The piston defines a rebound working chamber and compression working chamber. An active rebound valve is in fluid communication with the rebound working chamber through a rebound down tube, and an active compression valve is in fluid communication with the compression working chamber through a compression down tube. An intake compression valve is in fluid communication with the rebound working chamber through the rebound down tube, and an intake rebound valve is in fluid communication with the compression working chamber through the compression down tube. The opposite position of the intake valves balance the active rebound and compression valves to avoid asymmetric/bending loads on the inner tube in the damper.