A pressure relief valve for a fluid power assist steering system. The valve includes a housing and a spool disposed in the housing. The spool defines a cavity and has a first end and a second end. The spool is movable in the housing to limit an output pressure of the pump. A poppet seat is secured to the second end of the spool. A poppet is disposed in the cavity. A poppet spring biases the poppet into engagement with the poppet seat. A set screw is received in the first end of the spool. The set screw is rotatable relative to the spool to adjust a compression level of the poppet spring.

A valve signature diagnosis and leak testing device includes a spool valve operatively connected to a pilot valve, the pilot valve being configured to position the spool valve to one of an open position and a closed position. A blocker valve is fluidly connected to a control fluid outlet of the spool valve. An electrical module is operatively connected to the pilot valve, a supply of control fluid, and the blocker valve, the electrical module being capable of sending pulsed electrical signals to the pilot valve and the blocker valve to selectively position the spool valve and the blocker valve to an open or closed position.

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 hydraulic valve including a valve housing including a longitudinal axis, a receiving opening extending along the longitudinal axis, a first flow through opening of a supply connection, a second flow through opening of an operating connection, a third flow through opening of a tank connection, wherein the first flow through opening, the second flow through opening and the third flow through opening are configured at least partially flowable by a hydraulic fluid flowing through the valve housing, and a valve piston with a control groove which valve piston is axially displaceable in the valve housing in the receiving opening along the longitudinal axis, wherein the flow forces of the hydraulic fluid imparted upon the valve piston are oriented away from a first switching position of the hydraulic valve where the hydraulic fluid flows from the first flow through opening into the second flow through opening.

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 pressure regulator includes a cylinder and a piston contained in the cylinder. First and second O-rings are attached to the cylinder and configured to form a seal between the cylinder and an interior wall of the piston. The pressure regulator has a lubrication system that includes a lubrication reservoir between the first and second O-rings defined by an annular groove in an exterior surface of the piston and the interior wall of the cylinder, and an input port extending through the cylinder to the lubrication reservoir. The piston is configured to move along a central axis relative to the cylinder between first and second positions. The first and second O-rings are displaced from the input port during movement of the piston between the first and second positions.

A valve signature diagnosis and leak testing device includes a spool valve operatively connected to a pilot valve, the pilot valve being configured to position the spool valve to one of an open position and a closed position. A blocker valve is fluidly connected to a control fluid outlet of the spool valve. An electrical module is operatively connected to the pilot valve, a supply of control fluid, and the blocker valve, the electrical module being capable of sending pulsed electrical signals to the pilot valve and the blocker valve to selectively position the spool valve and the blocker valve to an open or closed position.

Hydraulic systems and associated methods configured to reduce leakage past a spool valve when the system is in a neutral state. Leakage reduction is achieved by shifting the spool valve within the spool bore. The shifting direction can depend on whether the system has a relatively high load or a relatively low load in the neutral state. The amount of shifting can depend on the pressure differential between the supply line and the work port, and/or the pressure differential between the work port and the tank line.

Hydraulic systems and associated methods configured to reduce leakage past a spool valve when the system is in a neutral state. Leakage reduction is achieved by shifting the spool valve within the spool bore. The amount of shifting can be controlled by a pressure controller that sets one or pressures in the system and actively/dynamically adjusts the system to achieve a desired pressure or set of pressures by shifting the spool valve.

A solenoid actuator is provided that includes a casing. A coil is positioned within the casing. A flux tube and axially separated pole piece are encircled by the coil. An armature is slidably mounted within bores of the flux tube and pole piece. The flux tube and pole piece are separated by a flux choke. A core shunt juxtaposes the pole piece from the flux choke. The core shunt, on major cross-sectional tubular thickness and a minor cross-sectional tubular thickness has an outer diameter of a curved shunt to provide enhanced performance stability.