Hydraulic pumps or motors of the radial cylinder type

A radial cylinder hydraulic pump or motor, comprising:

• a stator with a hollow guide element having a cylindrical inner surface,
• a rotor which is rotatably mounted within said guide element around an axis offset from the axis of said cylindrical inner surface, said rotor having a plurality of radial cylinders formed therein,
• a plurality of radial pistons slidably mounted within said cylinders and having radially outer ends each provided with a guide pad urged against said cylindrical inner surface,
• a continuous series of main rollers covering said cylindrical inner surface and interposed between said inner surface and each guide pad of said radial piston, said main rollers having ends supported by two supporting rings connected to said guide element,
• a plurality of auxiliary rollers individually interposed in a space between adjacent main rollers and said cylindrical inner surface to prevent direct contact of said adjacent main rollers,
• wherein the space between said main rollers is completely filled with oil, and
• wherein each of said guide pads is provided at a side thereof facing an associated radial piston with a sliding member interposed between the guide pad and the radial piston, said sliding member being slidably mounted on said guide pad between two end positions along a tangential direction with respect to the axis of rotation of said rotor, each guide pad being provided with spring means for biasing said sliding member towards an intermediate position between said two end positions.