Disclosed is hydraulic rotating equipment provided with a rotating shaft, a cylinder block including a plurality of cylinders, a like plurality of pistons accommodated in the cylinders, respectively, and a valve plate maintained in slide contact with a rear end surface of the cylinder block. The valve plate includes a low-pressure port communicable with the cylinders, a high-pressure port formed in an arcuate shape over a predetermined angle along a circumferential direction of the rotating shaft and communicable with the cylinders, a seal land maintained in slide contact with the rear end surface, and a sliding contact member arranged on a periphery of the seal land in a range of the predetermined angle along the circumferential direction of the rotating shaft and maintained in slide contact with the rear end surface. A working machine provided with the hydraulic rotating equipment is also disclosed.

A hydraulic pump, in particular an adjustable axial piston pump, has at least one piston (22) movable in a reciprocating manner in a longitudinal direction within a pump housing during operation of the hydraulic pump. The piston (22) has a link head (24), a piston top (54) opposite the link head (24), and at least one hollow chamber (60) surrounded at least partially by a piston housing (62) that substantially or completely terminates each hollow chamber (60) towards the outside. A piston (22) for such hydraulic pump is also provided.

A method for coating a pump component (23, 31), in particular, a part of an axial piston pump (7), having the steps of providing a blank of the component (23, 31), providing at least one recess in the blank, filling a powdery coating material into the associated recess, melting the coating material under a protective gas atmosphere and material-removing processing of the blank to form at least one sliding and/or bearing surface (6) from the coating.

A hydrostatic axial piston pump of swashplate construction, which is also configured to be operated as a motor, has a stationary control plate against which a rotating cylinder drum is tensioned. During operation, a tilting tendency of the cylinder drum arises in the direction of that quadrant of the control plate which is operatively connected to the first part of the displacement stroke of the pistons. The control plate has a supporting device configured for the cylinder drum. The supporting device is arranged adjacent to an outer edge of the control plate in the first quadrant thereof. The supporting device is configured to be formed by a hydrostatically relieved additional field.

A hydrostatic axial piston machine includes a control disk that has a permanent relief field and at least one hydrostatic auxiliary relief field.

An axial piston pump has a swash-plate construction, in particular for hydraulic systems. A cylinder drum (3) can be rotationally driven about a rotational axis (7) in a pump housing (1). Pistons (9) are axially displaceable and support at their actuation ends a swash plate (15). The swash plate can be pivoted by an adjusting device (21) to the desired angles of inclination relative to the rotational axis (7) for adjusting the stroke of the pistons (9) and the fluid pressure generated. The adjusting device has an adjusting piston (35) in a hydraulically actuated adjusting cylinder (31). Their movement can be transmitted to the swash plate (15) by a driven connection having a pivot joint (37, 39; 29, 43). The pivot joint is formed by a ball joint (37, 39) arranged between the piston (35) and the piston rod (41) of the adjusting cylinder (31).

A port plate for a swashplate type axial piston pump is described herein. The port plate includes an inlet port, a discharge port, and a first metering notch in fluidic communication via a first passage with a metering notch area adjustment valve configured to adjust the effective area of the metering notch. The first metering notch is disposed at a leading edge of one of the inlet port or the discharge port.

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.

A control plate (18) of a hydraulic machine is described, the control plate (18) includes a body (21), an arrangement of openings (22, 23), and a contact face (24). In order to operate a hydraulic machine with a low noise level the body (21) is made of a plastic material. The control plate may be used as port plate or as valve plate.

A control plate (18) of a hydraulic machine is described, the control plate (18) includes a body (21), an arrangement of openings (22, 23), and a contact face (24). In order to operate a hydraulic machine with a low noise level the body (21) is made of a plastic material. The control plate may be used as port plate or as valve plate.