A hydraulic radial piston device includes a housing, a pintle having a pintle shaft, a rotor mounted on the pintle shaft and defining a plurality of cylinders, and a plurality of pistons displaceable in the cylinders. The radial piston device further includes a piston ring that provides an interface for the pistons. The radial piston device includes various configurations for improving the performance and efficiency of the device.

A hydraulic radial piston device includes a housing, a pintle having a pintle shaft, a rotor mounted on the pintle shaft and defining a plurality of cylinders, and a plurality of pistons displaceable in the cylinders. The radial piston device further includes a piston ring that provides an interface for the pistons. The radial piston device includes various configurations for improving the performance and efficiency of the device.

A radial piston hydraulic motor comprising a box frame with a cam ring connected thereto, pistons in a piston frame and press rollers in the pistons, which press rollers can be pressed by means of the pressure of a hydraulic fluid, such as hydraulic oil, against an inner surface of the cam ring. The piston frame comprises connections between the interior space and passages, and a shutter valve is provided within each connection for controlling the hydraulic fluid flow through the connection between the passages and the interior space. The shutter valve is arranged to allow hydraulic fluid to flow from the passage into the interior space, when the pressure in the working pressure inlet passage, in the return passage and in the interior space is equal, i.e. the motor is in free-rotating state.

An object is displaced alternately in opposite directions, using a hydraulic power unit having a rotatable body which includes the shaft of a hydraulic machine having electronically commutated valves. A motor drives the rotatable body. The hydraulic machine drives an actuator to displace the object in use. Energy is transformed from rotational kinetic energy of the rotatable body to elastic strain energy or elastic strain and gravitational potential energy of the object during a pumping phase and rotation of the rotatable body slows, but does not change direction. The potential energy then drives the hydraulic machine to motor and the rotatable shaft speeds up again, storing rotational kinetic energy. The displacement of the hydraulic machine is controlled throughout to match a time varying demand taking into account the varying speed of rotation of the rotatable shaft. The motor provides energy to compensate for losses and the process can repeat cyclically.

An object is displaced alternately in opposite directions, using a hydraulic power unit having a rotatable body which includes the shaft of a hydraulic machine having electronically commutated valves. A motor drives the rotatable body. The hydraulic machine drives an actuator to displace the object in use. Energy is transformed from rotational kinetic energy of the rotatable body to elastic strain energy or elastic strain and gravitational potential energy of the object during a pumping phase and rotation of the rotatable body slows, but does not change direction. The potential energy then drives the hydraulic machine to motor and the rotatable shaft speeds up again, storing rotational kinetic energy. The displacement of the hydraulic machine is controlled throughout to match a time varying demand taking into account the varying speed of rotation of the rotatable shaft. The motor provides energy to compensate for losses and the process can repeat cyclically.

A hydraulic machine including: a casing rotatably mounted relative to a shaft; first brake means constrained to rotate with the casing; second brake means constrained to rotate with the shaft, and adapted to co-operate with the first brake means; a braking piston associated with return means and tending to exert a braking force; and a brake-release chamber adapted to be connected to a pressure force so as to apply a brake-release pressure selectively to the braking piston, so as to enable the first and second brake means to be separated; said hydraulic machine including a sweeping channel arranged in the shaft so as to define a leakage flow between the brake-release chamber and an internal volume of the casing.

A hydraulic machine including: a casing rotatably mounted relative to a shaft; first brake means constrained to rotate with the casing; second brake means constrained to rotate with the shaft, and adapted to co-operate with the first brake means; a braking piston associated with return means and tending to exert a braking force; and a brake-release chamber adapted to be connected to a pressure force so as to apply a brake-release pressure selectively to the braking piston, so as to enable the first and second brake means to be separated; said hydraulic machine including a sweeping channel arranged in the shaft so as to define a leakage flow between the brake-release chamber and an internal volume of the casing.

The hydraulic machine includes a cam and a cylinder block with pistons co-operating with cam lobes, each of which has two ramps extending between top and bottom dead center arcs. The cylinders are connected in alternation to a feed and to a discharge, in sequences separated by switchover stages including an isolation stage during which they are isolated relative to the feed and discharge main ducts. The angular position of the start or of the end of at least one first isolation stage relative to the corresponding dead center arc is different from the angular position of the start or of the end of at least one second isolation stage relative to its corresponding dead center arc, both of these dead center arcs being top dead center arcs or both of them being bottom dead center arcs.

The hydraulic machine includes a cam and a cylinder block with pistons co-operating with cam lobes, each of which has two ramps extending between top and bottom dead center arcs. The cylinders are connected in alternation to a feed and to a discharge, in sequences separated by switchover stages including an isolation stage during which they are isolated relative to the feed and discharge main ducts. The angular position of the start or of the end of at least one first isolation stage relative to the corresponding dead center arc is different from the angular position of the start or of the end of at least one second isolation stage relative to its corresponding dead center arc, both of these dead center arcs being top dead center arcs or both of them being bottom dead center arcs.

A hydraulic apparatus comprising a casing (1) having arranged therein a hydraulic machine (2), a shaft (4) mounted to rotate relative to the casing (1) by means of a bearing (5), a braking system (3) having a plurality of brake disks (31, 34) configured to prevent the shaft (4) rotating relative to the casing (1) in selective manner, and a control system (6, 7) for controlling said braking disks (31, 34), the hydraulic system including an irrigation system adapted to cool said brake disks (31, 34) by means of a fluid, the irrigation system including a fluid inlet (81) and a fluid outlet (82), the hydraulic system being characterized in that the fluid inlet and outlet (81, 82) of the irrigation system define a fluid flow within the casing in which the braking system (3) is downstream from the hydraulic machine (2).