Abstract: A hydraulic motor having a plurality of cylindrical pistons each of which is slidably mounted in a fluid tight manner along a respective cylindrical bore provided axially through a rotor keyed to a central rotatable shaft, each said piston being thrusted by a pressurized fluid with one end into contact with a flat surface of a toroidal member mounted to rotate about its own axis which is arranged at an angle to the axis of said central shaft, and rotation of said rotor causing each said piston to rotate about its own axis within the respective bore owing to said one end of each piston being shaped as a spherical bowl, the diameter of which is at least 0.7 times the radius of the respective piston divided by the sine of said angle.

Abstract: A hydraulic motor having a plurality of pistons slidably mounted in a fluid tight manner along respective bores provided axially through a rotor, which is keyed on a central shaft to rotate therewith and within a cavity of an outer casing, said pistons being axially movable with one of their ends in contact with an inclined plate facing one end of said rotor, and said cavity communicating with an inlet and an outlet for a pressurized hydraulic fluid via first and second header means facing the other end of said rotor and communicating with said bores via rotary distribution means formed by a toroidal member cooperating with said header means in a fluid tight manner and connected angularly to said rotor by means of a plurality of key means, each of which engages in a fluid tight manner a respective piston bore of said rotor and is connected to said toroidal member by an articulated joint; duct means being provided through each said key means and said toroidal member to connect each said piston bore to one of s