A multi piston machine includes a rotor, pistons, a first control valve, and a second control valve. The pistons abut against a cam surface with multiple lobes. The machine is switchable between at least three non-zero displacement volumes using the first and the second control valves. The first control valve is connected to a first and a third fluid chamber. The second control valve is connected to a second and a fourth fluid chamber. The first and the second control valve are connected to first and the second working port respectively. A third number of second control openings is twice a second number of the lobes. There is a first and a second group of the second control openings. Adjacent second control openings belong to a different first or second group. The second control openings of the first group are either connected to the first or the second fluid chamber.

A radial piston device includes a housing, a pintle attached to the housing and having a pintle shaft, a rotor rotatably mounted on the pintle shaft and having cylinders, pistons displaceably received in the cylinders, and a drive shaft coupled to the rotor and rotatably supported within the housing. The radial piston device includes mechanisms for reducing a pressure loss of hydraulic fluid flowing into the pintle shaft.

A hydrostatic radial piston unit of the cam-lobe type of construction having a non-rotary, stationary shaft defining a rotational axis of the hydrostatic radial piston unit. A non-rotary, stationary casing houses the shaft in a torque proof connection. A rotary casing is provided which is rotary around the rotational axis. A pair of roller bearings supports the rotary casing in a rotatable manner against the stationary casing, wherein the pair of roller bearings is arranged in an axial overlapping area in which the stationary casing and the rotary casing overlap.

A hydrostatic radial piston unit of the cam-lobe type of construction including a non-rotary, stationary casing. The stationary casing includes a through hole defining a rotational axis of the hydrostatic radial piston unit. A rotary casing is mounted rotary to the non-rotary, stationary casing in an axial overlapping area. A park brake mechanism includes at least two brake discs arranged adjoined in the overlapping area. An end cover closes the non-rotary casing on a rear end side of the hydrostatic radial piston unit facing away from the rotary casing. The end cover pre-tensions a disc spring against a disc-shaped brake piston both located in the rear end portion of the stationary casing to generate an axially oriented spring force. The force can be forwarded by the brake piston to at least one brake pin arranged in an axially oriented bore in the stationary casing, in order to press the brake discs against each other when the brake piston on the face opposite to the disc spring is not forced to move towards the end cover.

A radial piston pump 101 comprising a rotor 103 is disclosed. The rotor 103 includes a drive shaft 105 arranged to transmit rotary motion to or from the pump 101 and a piston housing 102 including at least one piston chamber 104, the at least one piston chamber 104 being arranged to receive a piston 108. The drive shaft 105 and the piston housing 102 are integrally formed.

A radial piston device includes a housing, a pintle attached to the housing and having a pintle shaft, a rotor rotatably mounted on the pintle shaft and having cylinders, pistons displaceably received in the cylinders, and a drive shaft coupled to the rotor and rotatably supported within the housing. The radial piston device includes mechanisms for reducing a pressure loss of hydraulic fluid flowing into the pintle shaft.

A hydrostatic radial piston unit of the cam-lobe type of construction having a non-rotary, stationary shaft defining a rotational axis of the hydrostatic radial piston unit. A non-rotary, stationary casing houses the shaft in a torque proof connection. A rotary casing is provided which is rotary around the rotational axis. A pair of roller bearings supports the rotary casing in a rotatable manner against the stationary casing, wherein the pair of roller bearings is arranged in an axial overlapping area in which the stationary casing and the rotary casing overlap.

A hydrostatic radial piston unit of the cam-lobe type of construction including a non-rotary, stationary casing. The stationary casing includes a through hole defining a rotational axis of the hydrostatic radial piston unit. A rotary casing is mounted rotary to the non-rotary, stationary casing in an axial overlapping area. A park brake mechanism includes at least two brake discs arranged adjoined in the overlapping area. An end cover closes the non-rotary casing on a rear end side of the hydrostatic radial piston unit facing away from the rotary casing. The end cover pre-tensions a disc spring against a disc-shaped brake piston both located in the rear end portion of the stationary casing to generate an axially oriented spring force. The force can be forwarded by the brake piston to at least one brake pin arranged in an axially oriented bore in the stationary casing, in order to press the brake discs against each other when the brake piston on the face opposite to the disc spring is not forced to move towards the end cover.