Manual displacement control device (MDC) for hydraulic units has an input shaft mounted rotatably about an input shaft axis in an input shaft block. The input shaft protrudes from the input shaft block with a first end, onto which a rotating torque can be applied. The MDC further includes a control spool housed in a control housing, which is moveable by means of rotating the input shaft for controlling a servo pressure. The control device has positioning means for adjusting and fixing the lateral position of the input shaft with respect to the control housing in a direction perpendicular to the input shaft axis and perpendicular to the direction of a restoring force exerted on the input shaft. The hydraulic unit is adjustable to its neutral position by means of a servo spring bracket providing an end stop surface for a servo spring seat towards the displacement element. The servo spring bracket is variably fixable to the hydraulic unit housing in a manner so that the orientation of the end stop surface can be adjusted parallel to the neutral position of the displacement element.

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.

Hydraulic axial piston unit having a rotational group for driving or being driven by a driving shaft, and a tiltable displacement element for adjusting the displacement volume of the rotational group. The rotational group includes a rotatable cylinder block in which working pistons are mounted reciprocally moveable in cylinder bores for conveying hydraulic fluid from a kidney-shaped inlet port to a kidney-shaped outlet port on a valve segment. At least two control ports are located on the valve segment each between the respective circumferential ends of the kidney-shaped inlet port and the outlet port. The control ports can be brought sequentially in fluid connection with the cylinder bores when the cylinder block is rotating. At least one hydraulic fluid injector is connected fluidly to one control port, for sequentially injecting pressurized hydraulic fluid via the control port into the passing cylinder bores. Via the other control port hydraulic fluid can be drained from passing cylinder bores.

A hydraulic motor apparatus includes a motor housing engaged to an end cap having a first porting system and an adapter connected to an external surface of the end cap and having a second porting system. A filter may be attached to the adapter and connected to the second porting system and a pressure reducing valve in the adapter is connected to the second porting system. The assembly may also include a controller operatively connected to the pressure reducing valve and system sensors measuring parameters affected by the output of the hydraulic motor apparatus, whereby the pressure reducing valve is operatively controlled by the controller in response to input from the system sensors.

An axial piston machine may include a housing, a guide, a shaft, at least two cylinders each delimited by an associated cylinder wall, at least two pistons, a feed configured to supply a working fluid, an exhaust configured to discharge the working fluid, and at least one actuator configured to open and close a plurality of secondary outlets. Each associated cylinder wall may include a primary outlet and a secondary outlet of the plurality of secondary outlets. Each primary outlet and each secondary outlet may be fluidically connected to an outlet chamber that is fluidically connected to the exhaust. Each primary outlet may open into an associated primary outlet channel that opens into the outlet chamber. Each secondary outlet may be fluidically connected to an associated secondary outlet channel that opens into the outlet chamber and is separate from the plurality of primary outlet channels.

An axial hydraulic pump-motor, in which a cylinder block having a plurality of cylinder bores on a valve plate having a high-pressure side port and a low-pressure side port for controlling an amount of reciprocation of a piston in each of the cylinder bores, the hydraulic pump-motor includes: a residual pressure release port provided on the valve plate and communicating until the cylinder bore on a top dead center side communicates with the low-pressure side port; a residual pressure acquisition portion obtaining a value of a residual pressure in the cylinder bore on the top dead center side; and a directional switching valve switching a flow path between the residual pressure release port and an hydraulic oil tank and a flow path between the residual pressure release port and the low-pressure side port.

Manual displacement control device (MDC) for hydraulic units has an input shaft mounted rotatably about an input shaft axis in an input shaft block. The input shaft protrudes from the input shaft block with a first end, onto which a rotating torque can be applied. The MDC further includes a control spool housed in a control housing, which is moveable by means of rotating the input shaft for controlling a servo pressure. The control device has positioning means for adjusting and fixing the lateral position of the input shaft with respect to the control housing in a direction perpendicular to the input shaft axis and perpendicular to the direction of a restoring force exerted on the input shaft. The hydraulic unit is adjustable to its neutral position by means of a servo spring bracket providing an end stop surface for a servo spring seat towards the displacement element. The servo spring bracket is variably fixable to the hydraulic unit housing in a manner so that the orientation of the end stop surface can be adjusted parallel to the neutral position of the displacement element.

An axial piston machine may include a shaft and a housing surrounding at least a portion of the shaft. A cylinder arrangement may be disposed within the housing in a circular manner. The cylinder arrangement may include a plurality of cylinders and a plurality of pistons each extending within each of the plurality of cylinders and may be constructed and arranged to drive the shaft. The plurality of cylinders may each include an expansion volume with an inlet and at least one outlet opening for a working medium. A cylinder head may be provided on the housing and may be constructed and arranged to close the plurality of cylinders of the cylinder arrangement. A cavity may be defined around the shaft in a central region of the cylinder arrangement and may be in operative communication with a plurality of auxiliary outlet openings of the expansion volume of each of the plurality of cylinders via a temporary connection. A cylindrical roller slider may rotate within the cavity in the central region of the cylinder arrangement and may be constructed and arranged to drive the shaft. A temporary connection between the cavity and the expansion volume of each of the plurality of cylinders may be formed by at least one of a channel through the cylindrical roller slider and a recess on an outside surface of the cylindrical roller slider. The recess may extend laterally from a casing of the cylindrical roller slider at a height of the plurality of auxiliary outlet openings in each of the plurality of cylinders and at a distance to the cavity in the central region of the cylinder arrangement.

The invention relates to a device (10) for controlling the displacement of a machine (20) with axial pistons comprising a case (23) that houses a control unit comprising a displacement control spool (110) adapted to be switched between two positions by a control pressure (Ps) according to an axis of sliding (): a working position wherein the control spool (110) provides a connection between at least one inlet (103, 104) that receives a supply pressure and an outlet (105, 106) connected to a cylinder for adjusting the inclination of said machine (31a, 31b), and an idle position wherein the control spool (110) interrupts the connection between said inlet (102, 104) and said outlet (101, 103), and comprising means for switching adapted to vary the position of the adjusting cylinder (31a, 31b), a spring (140), characterised in that: said means of communication comprise a second switching spool (130), coaxial to the control spool (110), a switching pressure (Pm) exerts an axial force on the second spool (130) in the direction of the control spool (110), the spring (140) exerts an axial force on the two spools (110, 130), which tends to move them apart from each other, control pressure (Ps) exerts an axial force on the control spool (110) in the direction of the second tool (130).

A hydraulic pump assembly for a vehicle is provided, comprising an electrical motor, a hydraulic pump driven by the electrical motor, and a centrifugal regulator connected with a pressure overflow valve connected to the oil outlet of the hydraulic pump, characterized in that the pump assembly further comprises at least two input check valves and at least two output check valves arranged such that a first pressure outlet port is formed when the motor is rotating in a first direction, and a second pressure outlet port is formed when the motor is rotating in an opposite direction.