A linear actuator system includes a linear actuator and at least one integrated pump assembly connected to the linear actuator to provide fluid to operate the linear actuator. The integrated pump assembly includes a pump with at least one fluid driver comprising a prime mover and a fluid displacement assembly to be driven by the prime mover such that fluid is transferred from a first port of the pump to a second port of the pump. The pump assembly also includes two valve assembles to isolate the pump from the system. The linear actuator system also includes a controller that establishes at least one of a speed and a torque of the at least one prime mover to exclusively adjust at least one of a flow and a pressure in the linear actuator system to an operational set point.

A hydraulic implement, which may be configured for attachment to a hydraulic system having a pressure line and a return line, may include a motor, an anti-cavitation valve, and an adjustable flow control valve. The motor may be operably connected between the pressure line and the return line and to rotate a shaft when hydraulic fluid flows from the pressure line through the motor to the return line. The anti-cavitation valve may be connected in parallel across the motor between the pressure line and the return line. The adjustable flow control valve may be connected in parallel across the motor between the pressure line and the return line. A method may include causing fluid to flow from the pressure line through an open adjustable flow control valve to the return line; and at least partially closing the valve to divert at least some fluid flow through the motor.

A power transfer unit includes a first hydraulic circuit, a second hydraulic circuit fluidly connected to the first hydraulic circuit, a pump and motor assembly fluidly connected between the first hydraulic circuit and the second hydraulic circuit, an isolation valve arranged along the first hydraulic circuit and fluidly connected to an inlet of the pump and motor assembly. The isolation valve is movable between a closed position and an open position to prevent and enable high-pressure fluid flow to the inlet, respectively. An unloader valve is arranged along the second hydraulic circuit and fluidly connected to an outlet of the pump and motor assembly, and an orifice is arranged along the second hydraulic circuit and fluidly connected to the unloader valve to reduce back pressure in the second hydraulic circuit.

A hydraulic-mechatronic system, for a vehicle that is connected to a target system, includes a housing with a fluid reservoir containing fluid, a communication port, a hydraulic pump, an electric motor for driving the hydraulic pump, at least one check valve, and a relief valve fluidly connected to the target system and the fluid reservoir. The relief valve moves between a first valve position, which is inactive and directs fluid to the communication port, and at least a second valve position, which is active and directs fluid from the communication port to the fluid reservoir. The hydraulic pump may rotate in forward and reverse directions. During operation of the hydraulic pump in the reverse direction, the relief valve is active such that the hydraulic-mechatronic system limits delivery of fluid through the communication port and instead directs fluid flow into the fluid reservoir of the housing.

A method for detecting and isolation a leak in a hydraulic system having a supply pump serving at least one control valve is disclosed. In one embodiment, the control valve has multiple work sections. In step of the method, the hydraulic system is activated. In another step, an actuation command for at least one of the work sections is received, for example from a human-to-machine interface. Subsequently, the method may include generating a flow demand for the work sections for which an actuation command has been received. The method also includes the step of implementing at least one of a first, second, third, and fourth leak detection and isolation protocol to detect and isolate a leak between the pump and the control valve assembly, a leak between the reservoir and the control valve assembly and a leak between the at least one work circuit and the control valve assembly.

To reduce the cost by reducing the number of parts and simplify the control of regeneration in the hydraulic actuator even though the meter-in control and the meter-out control can be performed separately while the supply and the discharge of hydraulic fluid is controlled. A meter-in valve that controls supply flow from a hydraulic pump into a hydraulic cylinder is provided, and meter-out switching valve that switches the direction of supply and discharge of the hydraulic oil into the hydraulic cylinder and controls the discharge flow from the hydraulic cylinder to the oil tank is installed on the down stream side of the meter-in valve, and further, a regeneration control valve is installed on the down stream side of the meter-out switching valve.

A hydraulic system (e.g., of an aircraft or other vehicle) includes a pump, a pressure line coupled to the pump and configured to distribute pressurized hydraulic fluid, and a return line configured to return hydraulic fluid to a reservoir. The hydraulic system also includes an auxiliary leakage valve coupled to the pressure line, to the return line, and to an actuator. The auxiliary leakage valve is configured to receive a control signal and, based on the control signal, selectively open a restricted fluid path. The restricted fluid path couples the pressure line to the return line to allow a restricted amount of the hydraulic fluid to flow from the pressure line to the return line.

Hydraulic fluid flushing valve for hydrostatic units usable in closed hydraulic circuit propel applications, having a flushing valve housing with a first inlet port connected to a first working line, a second inlet port connected to a second working line, and a discharge port for draining hydraulic fluid. A two-sided flushing valve flushing valve spool which can be shifted is mounted within the flushing valve housing in a cylindrical valve bore, which, in a shifted position, enables a fluid flow from one of the first or the second inlet port at which the lower hydraulic pressure is present, to the discharge port. The flushing valve spool includes on each side a pressure surface each of which is connected to one of the two inlet ports. At each side of the flushing valve spool a flushing valve spring is located in the flushing valve housing in such a manner that, when the flushing valve spool is in its centre, non-shifted position, at each side of the flushing valve spool a distance between a spring contact surface on the flushing valve spool and a spring support surface in the flushing valve housing is greater than the axial length of the corresponding flushing valve spring.

A first switching valve that switches between flow passages which allow communication between a first pressure-receiving chamber and a fluid supply device side and flow passages which allow communication between a second pressure-receiving chamber and the fluid supply device side, according to a change in a fluid pressure to be applied, and a second switching valve that is switched to flow passages which apply the fluid pressure to the first switching valve, are provided. The second switching valve includes return device, and is provided to be reciprocatable between an operation position to which the second switching valve is moved by a stroke of a piston and a return position to which the second switching valve is moved by the return device. The piston and the second switching valve are movable independently of each other.

The invention relates to a discharge pressure scale (30) consisting of at least one valve housing (41) having at least three fluid connection points in the form of a functional connector (A), a return flow connector (T) and a control connector (28), wherein a valve piston (52) is guided such that it moves longitudinally against the effect of an energy accumulator (42), moving from a respective opening or regulating position, against a valve seat (94), into a closed position, wherein the control (28) and return flow connectors (T) are separated from one another, characterised in that the fluid pressure present at the control connector (28) can be guided onto a pressure-active surface (A.sub.1*) of the valve piston (52) by means of a pressure compensation device (70) in such a way that it moves into its respective opening or regulating position in a pressure-compensated manner due to the force of the energy accumulator (42).