A valve assembly is adjustable in three independent ways allowing it to provide a variable input volume. The valve assembly has a base and an entrance plate. An outer guide, an inner guide and a shaft, each with a passage, are held together and the shaft is rotatable between the guides. The valve is open when the passages of the inner guide plate and shaft are aligned and closed when the passages are not aligned. The shaft RPM determines how many times per minute the valve opens. The open/closed ratio of the valve assembly determines how long the valve is open during each half revolution. The location of the shaft up or down in relationship to the inner guide determines what percentage of possible flow passes through the valve during each half revolution. The valve assembly can be used with either a gas or liquid medium.

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.

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 an inlet port to an outlet port on a valve segment. At least two control ports are located on the valve segment each between the 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 hydrostatic axial piston machine (1) with a cylinder barrel (2) having at least one piston bore (3) in which is located a power unit piston (4) supported on a cam disk (18). A control surface (5) is stationary relative to the housing and is on a control base (6), against which control surface the cylinder barrel (2) is in contact. In the control base (6) there are a kidney-shaped inlet connection (8) and a kidney-shaped outlet connection (9). The sealing web surface on the control surface 5 on the control base (6) in the vicinity of the inlet connection (8) is reduced, so that in operation as a motor, when there is a pressurization of the inlet connection (8), a reduction of the hydrostatic relief force is achieved. In operation as a motor, a residual application of the cylinder barrel (2) against the control surface (5) from a hold-down force of a hold-down spring (24) that is in an operative connection with the cylinder barrel (2) and/or pressing cylinder compression forces is preserved. In addition or alternatively, the terminal areas of the kidney-shaped inlet connection (8) of the control base (6) have a transitional contour (K) in the shape of a flattened arc in the radially outer area.