Control system and control method of a variable displacement hydraulic pump wherein the system includes a detection sensor for detection of the actually set displacement and a control unit for current control of a couple of solenoids controlling displacement increase and decrease.

An electromagnetic pump (100). The electromagnetic pump (100) comprises a conduit (101) comprising an inlet (103) and an outlet (105). A first magnetic field generating unit (109) is provided for generating a first magnetic field having a first component with a first direction in the conduit. A second magnetic field generating unit (111) is provided for generating a second magnetic field having a second component with a second direction in the conduit (101), the second direction being substantially opposite to the first direction. A piston member (113) is disposed within the conduit, the piston member (113) being moveable within the conduit (101) under the influence of the first and/or second magnetic fields to pump fluid received from the inlet (103) of the conduit (101) to the outlet (105) of the conduit (101).

A displacement control valve includes a housing a first, a second, and a third chamber; a valve body having a first reciprocating valve part that opens or closes discharge paths in the first chamber; and a solenoid that applies electromagnetic force to the valve body in the direction that closes the first valve part. The control valve has a spool valve part formed on the external circumference of the valve body and a spool seating part formed on the internal circumference of the valve housing and that is opened while the first valve part is closed and vice versa upon reciprocation of the valve body to control the rate of flow between a control chamber and an inlet chamber.

A capacity control valve includes: a valve housing having a Pc port, a Ps port and a Pd port; a main valve element which includes a main valve portion coming contacting and separating from a main valve seat opening and closing communication between the Pd port and the Pc port by a drive force of a solenoid; an intermediate communication path communicating the Pc port with the Ps port; and a pressure-sensitive valve opening and closing the intermediate communication path by an ambient pressure, in which the valve housing have a differential pressure valve housed therein, the differential pressure valve including a differential pressure valve element and opening and closing a communication between the Pc port and the Ps port by the differential pressure valve element moved by an operation force of an operation member operated by a discharge pressure Pd from the Pd port.

A measurement of the pressure of hydraulic fluid in a fluid working machine can be determined from the timing of the movement of valves which selectively seal a working chamber of cyclically varying volume from a fluid gallery. The timing of opening of a low pressure valve, to connect a working chamber to a low pressure fluid gallery, following the closure of a high pressure valve to seal a working chamber can be used to estimate the pressure in the high pressure fluid gallery at the moment of closure of the high pressure valve.

A magnetically damped check valve having a non-magnetic metal sleeve and a spring-biased poppet disposed within the check valve. The spring-biased poppet is operably supported by the sleeve. A poppet guide is attached to the sleeve. The poppet includes a shaft that is slidably attached to the poppet guide. A portion of the shaft extends into the sleeve. At least one magnet is attached to the portion of the shaft that extends into the sleeve. The magnet therefore moves with the shaft as the poppet moves in response to changes in differential pressure across the check valve. The magnet produces a magnetic field. As the magnet moves within the sleeve, the magnetic field changes thereby inducing an electrical current in the sleeve which produces another magnetic field that opposes the magnetic field of the magnet thereby damping the movement of the magnet and hence, damping the movement of the poppet.

The invention relates to a diaphragm pump comprising a diaphragm assembly and a diaphragm retrieval device comprising a tensile bar, said diaphragm assembly comprising a diaphragm and a diaphragm retaining device which secures said diaphragm, wherein the diaphragm assembly and the tensile bar are force-fittingly interconnected by means of a magnetic force of adhesion.

A valve unit for a fluid working machine comprise a valve having a valve member (and optionally a valve seat), a valve actuator coupled to the valve member, and an electronic actuator controller which is integral to the valve unit and configured to actively control the valve actuator to thereby control the valve member.

A displacement control valve includes a housing a first, a second, and a third chamber; a valve body having a first reciprocating valve part that opens or closes discharge paths in the first chamber; and a solenoid that applies electromagnetic force to the valve body in the direction that closes the first valve part. The control valve has a spool valve part formed on the external circumference of the valve body and a spool seating part formed on the internal circumference of the valve housing and that is opened while the first valve part is closed and vice versa upon reciprocation of the valve body to control the rate of flow between a control chamber and an inlet chamber.

A pump-valve integrated mechanism includes an air pump driven by a power source. A main air channel provided inside the valve base is connected to the air pump and has a decompression structure. The main air channel is connected to an air inflation structure which includes a branch air channel and an air nozzle. A check valve is provided inside the branch air channel. The branch air channel between the check valve and the air nozzle is provided with an air deflation hole. An electromagnetic valve is provided between the air nozzle, the air deflation hole, and the check valve. During air inflation, the electromagnetic valve controls the check valve to become connected to the air nozzle, and the air deflation hole is closed. During air deflation, the electromagnetic valve controls the air nozzle to become connected to the air deflation hole and the check valve is closed.