Abstract: 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.

Abstract: A radial piston hydraulic motor comprising a box frame with a cam ring connected thereto, pistons in a piston frame and press rollers 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 of the cam ring. The piston frame comprises connections between the interior space and passages, and a shutter valve is provided within each connection for controlling the hydraulic fluid flow through the connection between the passages and the interior space. The shutter valve is arranged to allow hydraulic fluid to flow from the passage into the interior space, when the pressure in the working pressure inlet passage, in the return passage and in the interior space is equal, i.e. the motor is in free-rotating state.

Abstract: A radial piston hydraulic motor comprising a box frame with a cam ring connected thereto, pistons in a piston frame and press rollers 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 of the cam ring. The piston frame comprises connections between the interior space and passages, and a shutter valve is provided within each connection for controlling the hydraulic fluid flow through the connection between the passages and the interior space. The shutter valve is arranged to allow hydraulic fluid to flow from the passage into the interior space, when the pressure in the working pressure inlet passage, in the return passage and in the interior space is equal, i.e. the motor is in free-rotating state.