A piston hydraulic device comprises a cylinder block having a plurality of cylinder assemblies and is rotatable about a first rotation axis. Each cylinder assembly comprises a cylinder and a piston. A port plate has a first port and a second port that are angularly spaced relative to the first rotation axis. A plurality of first conduits connect respective cylinders alternately to the first port or the second port. At least one second conduit is connected to a fluid reservoir. At least one directional control valve is positioned in the first conduit and fluidly connects to the second conduit. The at least one directional control valve connects the cylinder to the port plate in a first position and to the fluid reservoir in a second position. A controller is operatively associated with the directional control valve for switching between the first and the second positions.

A piston hydraulic device comprises a cylinder block having a plurality of cylinder assemblies and is rotatable about a first rotation axis. Each cylinder assembly comprises a cylinder and a piston. A port plate has a first port and a second port that are angularly spaced relative to the first rotation axis. A plurality of first conduits connect respective cylinders alternately to the first port or the second port. At least one second conduit is connected to a fluid reservoir. At least one directional control valve is positioned in the first conduit and fluidly connects to the second conduit. The at least one directional control valve connects the cylinder to the port plate in a first position and to the fluid reservoir in a second position. A controller is operatively associated with the directional control valve for switching between the first and the second positions.

Methods and systems for a bent axis motor are described. In one example, a bent axis motor includes a valve plate coupled to at least one piston of a cylinder block, the valve plate comprising a first plurality of grooves spaced about openings of the valve plate on a first side of the valve plate facing the cylinder block, the valve plate further comprising a second plurality of grooves arranged on a second side of the valve plate facing away from the cylinder block.

Methods and systems for a bent axis motor are described. In one example, a bent axis motor includes a valve plate coupled to at least one piston of a cylinder block, the valve plate comprising a first plurality of grooves spaced about openings of the valve plate on a first side of the valve plate facing the cylinder block, the valve plate further comprising a second plurality of grooves arranged on a second side of the valve plate facing away from the cylinder block.

A pump, including: a cylinder block including two through-bores and two pistons disposed in the through-bores; a drive shaft to rotate the cylinder block; a swash plate to displace the pistons within the through-bores to draw fluid through an inlet port into the through-bores; and expel the fluid from the through-bores into the outlet port; a torque sensor arranged to measure torque on the drive shaft and transmit a torque signal, including the measured torque, to a processor; and an actuator to receive, from the processor, a control signal generated using the torque signal and pivot the swash plate about a first axis, transverse to the axis of rotation, or maintain a circumferential position of the swash plate about the first axis; or pivot the cylinder block about a second axis, transverse to the axis of rotation, or maintain a circumferential position of the cylinder block about the second axis.

A hydraulic machine comprising: an outer casing comprising a first front plate and a second front plate, a shaft rotatable about a main axis, a first rotor comprising a first rotor body rotatable with said shaft around said main axis, and a plurality of first pistons with respective spherical ring heads fixed to said first rotor body, a second rotor comprising a second rotor body and a plurality of second pistons with respective spherical ring heads, wherein the second rotor is rotatable about a secondary axis, inclined with respect to said main axis, a plurality of sleeves that are separate and independent from each other, each having a cylinder open at opposite ends and engaged on opposite sides by a first piston and by a second piston.

The invention relates to a method and a device for determining of at least one end position of a displacement element of an adjustable hydraulic machine, in particular of the axial piston type, shiftable or displaceable between two ends position a by means of a displacement unit between a first end position and a second end position. According to the invention the determination of having reached an end position of displacement takes place by means of a measurement circuit, whose electrical characteristics are changed jumpily when an end position is reached. This is done by connecting a partial branch of the measuring circuit with earth, when a moveable element comes into electric contact with a limit stop assigned to the corresponding end position.

A rotatable piston assembly for a reciprocating piston type hydraulic machine includes a rotatable piston configured for a controlled rotation and configured to reciprocate within a cylinder bore of the reciprocating piston type hydraulic machine.

A rotatable piston assembly for a reciprocating piston type hydraulic machine includes a rotatable piston configured for a controlled rotation and configured to reciprocate within a cylinder bore of the reciprocating piston type hydraulic machine.

In general, certain embodiments of the present disclosure provide an electro-hydrostatic actuator comprising a piston assembly and a hydraulic cylinder. The piston assembly, having a piston head and a piston rod extending from the piston head, is located and movable within the hydraulic cylinder. The hydraulic cylinder includes a hydraulic fluid chamber region including a piston side chamber and a rod side chamber, a reservoir for storing hydraulic fluid located within the hydraulic cylinder which is in fluid communication with the hydraulic fluid chamber region. The electro-hydrostatic actuator includes a hydraulic pump system for moving hydraulic fluid in the reservoir and the hydraulic fluid chamber region, the hydraulic pump system in fluid communication with a flow control network in a hydraulic cylinder boss for controlling a direction and flow magnitude of hydraulic fluid within the hydraulic fluid chamber region, and an electric motor for driving the hydraulic pump system.