RADIAL PISTON HYDRAULIC MOTOR AND METHOD FOR CONTROLLING RADIAL PISTON HYDRAULIC MOTOR

摘要

A radial piston hydraulic motor comprising a box frame (10) with a cam ring (11) connected thereto,pistons (13a1, 13a2…) in a piston frame (12) and press rollers (14a1, 14a2…) 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 (11') of the cam ring. The piston frame (12) comprises connections (120) between the interior space (K)and passages(22), and a shutter valve (110) is provided within each connection (120) for controlling the hydraulic fluid flow through the connection (120) between the passages (22) and the interior space (K). The shutter valve (110) is arranged to allow hydraulic fluid to flow from the passage (22) into the interior space (K), when the pressure in the working pressure inlet passage (B), in the return passage (A) and in the interior space is equal, i.e. the motor is in free-rotating state.