Abstract: A radial piston hydrostatic machine having a first fluid displacement stage and a second fluid displacement stage, the machine having an outer housing structure for defining an internal chamber, a drive-shaft supported in the housing and operatively connected to a cylinder-barrel located within the internal chamber, the cylinder-barrel having a number of radial cylinders and each cylinder containing a piston operatively connected to a surrounding annular track-ring, the cylinder-barrel and pistons defining a rotating-group and where the rotating-group is positioned in a sub-chamber generally defined axially by the width of the track-ring and radially by the radial distance between the cylinder-barrel and surrounding track-ring.

Abstract: A housing structure for a hydrostatic machine comprising two shells of part-cylindrical form. The shells are connectable together at their junction surfaces on a parting-plane. A drive-shaft is supported in the housing structure and its axis of rotation lies on the parting-plane, this being the axis of symmetry of the shells. The shells are identical in cast shape, and have symmetrically arranged recesses and surface features to either side of said axis of symmetry. In the interior chamber between the shells, working component elements of the machine are located and driven by the drive-shaft to convert mechanical power into hydraulic power passing through openings or fluid-passageways provided in the housing structure.

Abstract: A radial piston hydrostatic machine having an outer housing structure comprising at least two housing elements connectable together along a parting-plane arranged perpendicular to the rotational axis of said drive-shaft to define an internal chamber, a drive-shaft supported in the housing to drive the cylinder-barrel, the cylinder-barrel having a number of radial cylinders, each cylinder containing a piston such that the pistons can bear on the track-ring, fixed abutment means in the housing and disposed radially adjacent the track-ring for resisting the action of the pistons on the track-ring and suppressing vibration emanating from the track-ring.