A four-quadrant radial piston hydraulic device includes a housing, plunger assemblies, an eccentric spindle rotatably disposed on the housing, pilot-operated check valves one-to-one corresponding to the plunger assemblies, two-way cartridge valves one-to-one corresponding to the plunger assemblies, a distribution shaft and a confluence plate. A reversing slide valve is disposed on the confluence plate. A working method of a four-quadrant radial piston hydraulic device is also provided. When the radial piston hydraulic device is used as a hydraulic motor and a hydraulic pump, it is capable of realizing two-way rotation, which solves a limitation of valve flow distribution in motor application.

A four-quadrant radial piston hydraulic device includes a housing, plunger assemblies, an eccentric spindle rotatably disposed on the housing, pilot-operated check valves one-to-one corresponding to the plunger assemblies, two-way cartridge valves one-to-one corresponding to the plunger assemblies, a distribution shaft and a confluence plate. A reversing slide valve is disposed on the confluence plate. A working method of a four-quadrant radial piston hydraulic device is also provided. When the radial piston hydraulic device is used as a hydraulic motor and a hydraulic pump, it is capable of realizing two-way rotation, which solves a limitation of valve flow distribution in motor application.

A motor (10) to be driven by a pressurized fluid includes a manifold (16) with an arcuate surface (20) defining a valve opening (22) surrounded by a sealing surface. A cylinder (26) has an aperture (30) cooperating with the arcuate surface (20). The cylinder (26) is pivotally mounted so as to be pivotable between a neutral state in which the aperture faces the sealing surface, an inlet state in which the aperture (30) is in fluid connection with the valve opening (22), and an exhaust in which the aperture (30) is in fluid connection with a drainage volume. A piston (34), deployed in the cylinder (26), is driven to extend by pressure within the cylinder. The piston is linked to a crank (36) so that rotation of a crankshaft (38) causes a cyclic motion of the piston (34) and cylinder (26) from the inlet state for an extension power stroke of the piston (34), through the neutral state and to the exhaust state for a return motion of the piston (34). The pivot axis of the cylinder, preferably implemented using a pivot axle (32), is located between the crankshaft axis and the arcuate surface (20).

A motor (10) to be driven by a pressurized fluid includes a manifold (16) with an arcuate surface (20) defining a valve opening (22) surrounded by a sealing surface. A cylinder (26) has an aperture (30) cooperating with the arcuate surface (20). The cylinder (26) is pivotally mounted so as to be pivotable between a neutral state in which the aperture faces the sealing surface, an inlet state in which the aperture (30) is in fluid connection with the valve opening (22), and an exhaust in which the aperture (30) is in fluid connection with a drainage volume. A piston (34), deployed in the cylinder (26), is driven to extend by pressure within the cylinder. The piston is linked to a crank (36) so that rotation of a crankshaft (38) causes a cyclic motion of the piston (34) and cylinder (26) from the inlet state for an extension power stroke of the piston (34), through the neutral state and to the exhaust state for a return motion of the piston (34). The pivot axis of the cylinder, preferably implemented using a pivot axle (32), is located between the crankshaft axis and the arcuate surface (20).

A hydraulic transmission comprising a variable displacement pump and motor, at least one having cylinders having valves which are controllable on each cycle of cylinder working volume to determine the net displacement of working fluid by the cylinder. The transmission has a valve control module which determines a displacement of the pump and the motor by specifying a displacement demand. The pump and/or motor valve control module determine the frequency of intensity peaks in the frequency spectrum of the pattern of cylinders carrying out active and inactive cycles of cylinder working volume using a first procedure and, if these will fall within disallowed frequency bands including the resonant frequency of components with which the transmission is in mechanical communication, the displacement demand, or another input, is periodically modified to suppress generation of those frequencies. The hydraulic transmission is useful for example in a wind turbine generator, or a vehicle.

A hydraulic transmission comprising a variable displacement pump and motor, at least one having cylinders having valves which are controllable on each cycle of cylinder working volume to determine the net displacement of working fluid by the cylinder. The transmission has a valve control module which determines a displacement of the pump and the motor by specifying a displacement demand. The pump and/or motor valve control module determine the frequency of intensity peaks in the frequency spectrum of the pattern of cylinders carrying out active and inactive cycles of cylinder working volume using a first procedure and, if these will fall within disallowed frequency bands including the resonant frequency of components with which the transmission is in mechanical communication, the displacement demand, or another input, is periodically modified to suppress generation of those frequencies. The hydraulic transmission is useful for example in a wind turbine generator, or a vehicle.

The hydraulic apparatus is set so that the ratio of the pressure-receiving area of the respective bottom oil chambers of the boom cylinder, the arm cylinder and the bucket cylinder to the pressure-receiving area of the respective rod oil chambers matches the ratio of the extruded volume drawn into or discharged from the bottom oil chambers per single rotation by the respective extrusion members of the first hydraulic pump motor, the second hydraulic pump motor and the third hydraulic pump motor to the volume discharged from or drawn into the rod oil chambers.

The invention relates to a hydrostatic radial piston motor, in particular a hydrostatic radial piston motor for actuating a differential cylinder. According to the invention, the hydrostatic motor in radial piston configuration comprises a control stud in a housing, the hydrostatic motor having three hydraulic working connections. The first working connection can be connected to the piston-end of a differential cylinder, while the second working connection can be connected to the rod-end of the differential cylinder. Finally, the third working connection can be connected to a tank. Owing to this arrangement, the differential cylinder can be directly operated with the aid of a single hydrostatic motor, with it being possible to forgo interposing proportional or control valves.

A hydraulic apparatus including an electronically commutated machine having a plurality of working chambers which are controlled on each cycle of working chamber volume to carry out active or inactive cycles of working chamber volume allows only a plurality of defined fractions of cycles to be active cycles to avoid generating frequencies of active cycles which cause low frequency resonances. The demand signal may be quantised into fractions m/n where n is an integer below a threshold selected to avoid repeating patterns of active cycles of more than a cut-off length.

A hydraulic apparatus including an electronically commutated machine having a plurality of working chambers which are controlled on each cycle of working chamber volume to carry out active or inactive cycles of working chamber volume allows only a plurality of defined fractions of cycles to be active cycles to avoid generating frequencies of active cycles which cause low frequency resonances. The demand signal may be quantised into fractions m/n where n is an integer below a threshold selected to avoid repeating patterns of active cycles of more than a cut-off length.