A servovalve includes a fluid transfer valve assembly comprising a supply port and a control port a moveable valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal; and a jet pipe assembly configured to direct fluid to the ends of the spool to axially move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow. The jet pipe assembly includes a jet pipe and a connector header fluidly connecting the jet pipe to a nozzle via which fluid is directed to the spool ends. One or more openings is provided in the spool such that fluid from the supply port flows into the interior of the spool and into the jet pipe and to the nozzle via the connector header.

A valve, in particular a proportional pressure regulating valve, has a valve piston (12) longitudinally movable in a valve housing (10) for alternately releasing and connecting a user connection (A) to a pressure supply port (P) or a tank connection (T). The valve piston can be actuated by an actuating magnet (14) that produces a dither signal during operation. The valve piston (12) reaches a floating position within the valve housing (10) by a hydraulic lift limitation for the receipt of the dither signal.

A pressure regulating valve includes a housing, control slide valve, coupling rod, armature, outlet port, and pressure transmission pin. The armature demarcates a first fluid space and a second fluid space from each other. The rod extends with a constant first outer cross-sectional shape in a direction of a longitudinal axis, and at least partially demarcates a third fluid space that fluidically connects the first fluid space to the outlet port. The pin extends with a constant second outer cross-sectional shape in the direction of the longitudinal axis, and at least partially delimits the third fluid space. The pin is positioned so that one end facing toward the armature projects into the control slide valve, and another end facing away from the armature is at least indirectly supported against the housing. A hydraulically effective area of the second shape is larger than a hydraulically effective area of the first shape.

A pressure-maintaining valve arrangement of a purge circuit of a closed hydraulic circuit includes a pressure-maintaining valve configured to be shut off via a pilot valve. In one embodiment, a control pressure chamber, acting in the closing direction, of the pressure-maintaining valve is configured to be relieved via the pilot valve to a tank, and the pressure-maintaining valve is closed via a spring acting in the closing direction. In another embodiment, the valve arrangement includes an additional control pressure chamber acting in the closing direction. The additional control pressure chamber is configured to be loaded via the pilot valve, and the pressure-maintaining valve closes. The pressure of the inlet of the pressure-maintaining valve is used for this purpose.

A valve device has a valve housing and a main piston (4) arranged in an axially slidable manner in a piston bore of the valve housing (2). A first consumer connection (A) and a second consumer connection (B) can be alternately connected to a pressure connection (P) and a tank connection (T1, T2) by the action of a first magnetic actuating system (6) and a second magnetic actuating system (8) with two pilot pistons (14, 16). In an actuated state of the respective pilot piston (14, 16), the main piston (4) follows the movement of the pilot piston (14, 16) due to the force ratio adjusting itself to actuate the fluid-carrying connection between the pilot chamber (10, 12) of the pilot piston (14,16) and the assignable tank connection (T1, T2) such that pilot oil flows.

A balancing valve includes four ports. While the pressures at a pair of balancing ports of a hydraulic balancing valve are equal, the valve maintains two other ports in a closed position. Upon a pressure differential between the balancing ports, fluid communication can occur between one of the balancing ports and either of the other ports based upon the direction of the pressure differential. A hydraulic ride control system utilizes the balancing valve together with other control valves to provide ride control functionality.

An airflow control valve (20) for use in a breathing apparatus (10) to control a flow of air from a pressurized air supply to a respirator. The valve comprises an inlet port (31) for connection to a pressurized air supply, and first (32) and second (33) outlets. The valve is configurable between a first position in which the inlet port is in restricted fluid communication with the first outlet to allow a restricted flow of air from the inlet port to the first outlet and in which the second outlet is sealed from the inlet port and, a second position in which the inlet port is in substantially unrestricted fluid communication with the second outlet to allow an unrestricted flow of air from the inlet port to the second outlet.

A flow control valve includes a valve body having an bore and a plurality of fluid ports in communication with the bore. A valve spool is axially slidably disposed in the valve body, and an end portion of an end of the valve spool has a convex curved surface. A linear actuator is disposed at one end of the valve body and includes an armature slidable along an axial direction of the valve spool. The armature includes a head portion having a convex curved surface configured to abut against the end portion of the valve spool. The engagement structure between the valve spool and the armature of the flow control valve is improved, which enables the valve spool and the armature to be automatically aligned. This reduces the precision requirement of contact between the valve spool and armature, which facilitates mass production and reduces cost of the valves.

A hydraulic suspension system includes a suspension cylinder, a pump, and a control valve therebetween. The control valve includes a spool reciprocally movable between a pump flow position and a tank flow position in which a control port of the control valve is in communication with a pump and a tank, respectively. A piloted logic element in fluid communication with and interposed between the control valve and the suspension cylinder is selectively movable between a through-flow position in which fluid can flow in either direction between a chamber of the suspension cylinder and the control port of the control valve and a blocked position in which fluid is prevented from flowing in or out of the chamber of the suspension cylinder. The logic element is biased to the blocking position, moving to the through-flow position when subjected to a crack pressure delivered from the control port of the control valve.

A displacement control valve is provided for discharging liquid refrigerant in a control chamber at startup and achieves a reduction in startup time and an improvement in operating efficiency during control of a variable displacement compressor simultaneously. The opening area between communicating holes in a third valve section and a third valve seat surface in a control area to control the flow rate or pressure in a working control chamber is set smaller than the area of auxiliary communicating passages.