A radial piston hydraulic motor comprising a hollow rotating shaft inside the motor, which rotating shaft is arranged to rotate around its axial central axis A for providing torque from the radial piston hydraulic motor, wherein the rotating shaft comprises a piston frame with pistons, which are arranged to move radially, the piston frame comprises a distribution surface, which is a flat surface in parallel plane with the radial movement of the pistons, and a first inner surface extending in axial direction around the axial central axis A, wherein the rotating shaft comprises a half shaft having a second inner surface extending in axial direction around the axial central axis A, wherein piston frame and the half shaft are arranged adjacent to each other so that the first inner surface and the second inner surface form a surface, in axial direction, forming a cavity inside the rotating shaft for receiving a drive shaft.

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 hydraulic transmission circuit is provided having at least two elementary hydraulic motors, each having a secondary enclosure and a main duct for fluid feed and a secondary enclosure and a main duct for fluid discharge. A fluid distributor distributes fluid from the main ducts to the elementary motors via the secondary enclosures. A control system controls the elementary motors. Valves connecting the fluid distributor to the secondary enclosures of the first motor put a secondary enclosure into communication with a main duct independent of an operating mode of any other elementary motor.

The assembly may include a cylinder block, a plurality of pistons, and a holding element, the holding element extending over all or part of the outer periphery of the cylinder block. The holding element may include a plurality of guide portions, each partially blocking a recess of the cylinder block so as to come into contact with a planar end of the crown of a piston to guide in the translation of each piston in their respective recesses. The holding element may include two indexing means cooperating with two indexing means of the cylinder block so as to hold the holding element under a traction force when positioned around the cylinder block.

Methods, systems, and techniques for harnessing wind energy use a tethered airfoil and a digital hydraulic pump and motor, which may optionally be a combined pump/motor. During a traction phase, a wind powered airfoil is allowed to extend a tether and a portion of the wind energy harnessed through extension of the tether is stored prior to distributing the wind energy to an electrical service. During a retraction phase, the wind energy that is stored during the traction phase is used to retract the tether. The digital hydraulic pump and motor are mechanically coupled to the tether.

The assembly may include a cylinder block, a plurality of pistons, and a holding element, the holding element extending over all or part of the outer periphery of the cylinder block. The holding element may include a plurality of guide portions, each partially blocking a recess of the cylinder block so as to come into contact with a planar end of the crown of a piston to guide in the translation of each piston in their respective recesses. The holding element may include two indexing means cooperating with two indexing means of the cylinder block so as to hold the holding element under a traction force when positioned around the cylinder block.

The distributor phase shifter for a hydraulic pump motor (300) is provided for a hydraulic pump motor (1) which includes a pump motor housing (2) and a pump motor central rotor (3) to which an input-output distributor (43) presents an input-output angular collector of an internal conduit (44) and an input-output angular collector of an external conduit (89), which phase shifter includes a phase shift acting element (301) which is supported on the housing of the pump motor (2) in order to make the input-output distributor (43) rotate around its longitudinal axis and over a determined angular range.

Methods, systems, and techniques for harnessing wind energy use a tethered airfoil and a digital hydraulic pump and motor, which may optionally be a combined pump/motor. During a traction phase, a wind powered airfoil is allowed to extend a tether and a portion of the wind energy harnessed through extension of the tether is stored prior to distributing the wind energy to an electrical service. During a retraction phase, the wind energy that is stored during the traction phase is used to retract the tether. The digital hydraulic pump and motor are mechanically coupled to the tether.

Hydrostatic radial piston unit comprising a front case part accommodating a drive shaft via shaft bearing means so that the drive shaft can rotate around a central axis relative to the front case part. A rear case part is attached on one side to the front case part and closed on another side in order to define an internal volume. A cylinder block is disposed in the internal volume and attached to the drive shaft in a torque proof manner. Axially disposed timing holes in the cylinder block connect radially oriented working volumes in the cylinder block with a cylinder block front face that is arranged perpendicularly to the central axis and faces away from the front case part. Integrally within the rear case part internal annular flow passages are formed and are connected to an inlet and an outlet of the radial piston unit and running basically in circumferential direction around the central axis. Internal distribution conducts configured to hydraulically connect the internal annular flow passages with the cylinder block timing holes are integrally formed within the rear case part, too.

A radial piston motor includes a cam body and a working member. The cam body includes circumferentially arranged lobes. Each lobe includes a cam section for guiding a piston radially outwards. Each cam section includes a deceleration phase configured to radially decelerate an engaging piston in the case of constant rotational speed and an acceleration phase configured to radially accelerate an engaging piston in the case of constant rotational speed. The working member is rotatable relative to the cam body and has circumferentially arranged pistons. The number of pistons and the number of lobes have the number one as the only common factor and the numbers differ from each other. The deceleration phase is smaller than the acceleration phase.