Systems and methods are provided for a hydraulic axial piston assembly. The hydraulic axial piston assembly may include a distributor plate, a bearing element directly and orthogonally connected to a side of the distributor plate, and an adjustment screw orthogonally connected to the bearing element, where the adjustment screw is externally accessible and manually rotatable to adjust a timing angle of the distributor plate.

A hydrostatic positive displacement machine has a cylinder drum (4) located in a housing (9) and rotatable around an axis of rotation (2). During rotation of the cylinder drum (4), a piston bore (5) is placed in alternating communication with an inlet side (E) and an outlet side (A). The inlet side (E) and outlet side (A) comprise connections (21; 22) to a control plate (12). A reversing device (30) is located in a reversing area (25; 26) between the connections (21, 22) on the control plate (12). The reversing device (30) damps the pressure adjustment between a displacement chamber (V) and the pressure present in the connection (21; 22). The reversing device (30) includes at least two flow connections which are actuated simultaneously by the displacement chamber (V) as it moves along the reversing area (25; 26).

A valve plate or end cap includes a running surface having a pair of arcuate kidney ports formed thereon. The running surface also includes a plurality of pressure gradient grooves formed on the running surface, each pressure gradient groove having a proximal end adjacent to a respective one of the ends of one of the kidney ports and a distal end. The distal end of one of the pressure gradient grooves associated with one kidney port may overlap the distal end of a pressure gradient groove associated with the other kidney port. The distal end of at least one of the pressure gradient grooves is located outside the circumference of a pitch circle that passes through the center of each kidney port. The distal end of at least one of the other pressure gradient grooves is located inside the pitch circle circumference.

An axial-type hydraulic pump/motor in which a cylinder block with a plurality of cylinder bores formed around a rotation axis slides with respect to a valve plate that has a valve plate discharge port and a valve plate suction port, and controls the amount of reciprocation of a piston in each cylinder bore depending on the inclination of a swash plate. Based on the rotational direction of the cylinder block, an opening shape of an end portion on the front side in the rotational direction of a cylinder port and an opening shape of an end portion on the rear side in the rotational direction of the valve plate suction port PB1 have the same shape or partially have the same shape.

The invention relates to a hydraulic pump wherein a barrel is in sliding connection with a shaft and is driven in rotation by the shaft. A housing is formed in the barrel, the shaft sliding in the housing while projecting from the front face of the barrel. The housing and the shaft defining between them a balancing chamber, the balancing chamber being connected to a delivery aperture in such a way that fluid in the balancing chamber exerts a compressive force on the barrel which tends to press the barrel against a port plate.

Systems and methods for a hydraulic machine. The hydraulic machine includes, in one example, a rotational shaft, a central pin rotationally coupled to the rotational shaft and threadingly engaged with a cylinder block via a threaded interface, and pistons coupled to the rotational shaft and mated with cylinders in the cylinder block. The hydraulic machine further includes a distribution plate in fluidic communication with the cylinders and a fluid inlet and a fluid outlet.

A valve plate of a hydraulic pump/motor, includes a high pressure-side port and a low pressure-side port, a first oil groove provided to be endless in an outer peripheral part of the high and low pressure-side ports, and a plurality of second oil grooves. Further, a plurality of pad oil grooves communicating with the first oil groove and opened toward the end face of the cylinder block is provided in an outer peripheral portion of the high pressure-side port, at least in a portion being on a downstream side of the relative rotation, in a pad region contacting the end face of the cylinder block, and the plurality of pad oil grooves is provided such that a proportion of an opening area to the end face of the cylinder block is larger on the downstream side than on an upstream side of the relative rotation.

A valve plate of a hydraulic pump/motor, includes a high pressure-side port and a low pressure-side port, a first oil groove provided to be endless in an outer peripheral part of the high and low pressure-side ports, and a plurality of second oil grooves. Further, a plurality of pad oil grooves communicating with the first oil groove and opened toward the end face of the cylinder block is provided in an outer peripheral portion of the high pressure-side port, at least in a portion being on a downstream side of the relative rotation, in a pad region contacting the end face of the cylinder block, and the plurality of pad oil grooves is provided such that a proportion of an opening area to the end face of the cylinder block is larger on the downstream side than on an upstream side of the relative rotation.

An integrated electro-hydraulic unit including an electric machine, a hydraulic machine, and a shared casing. The electric machine includes a winding and a stator. The hydraulic machine includes a shaft, a cylinder block, a plurality of pistons, and a valve plate. The shared casing includes a cooling channel located between the electric machine and the hydraulic machine. By action of the pistons, a first port on the valve plate receives working fluid pulled into the cylinder block and a second port on the valve plate receives working fluid pushed out. By action of the pistons, a third port on the valve plate is configured to receive a cooling flow of the working fluid. The cooling flow through the third port is separate from the first port and the second port, such that volumetric efficiency measured between the first port and the second port is not affected by the cooling flow.

An integrated electro-hydraulic unit including an electric machine, a hydraulic machine, and a shared casing. The electric machine includes a winding and a stator. The hydraulic machine includes a shaft, a cylinder block, a plurality of pistons, and a valve plate. The shared casing includes a cooling channel located between the electric machine and the hydraulic machine. By action of the pistons, a first port on the valve plate receives working fluid pulled into the cylinder block and a second port on the valve plate receives working fluid pushed out. By action of the pistons, a third port on the valve plate is configured to receive a cooling flow of the working fluid. The cooling flow through the third port is separate from the first port and the second port, such that volumetric efficiency measured between the first port and the second port is not affected by the cooling flow.