CIRCULAR ROLLING MILL WITH SHAPING ROLLERS AND METHOD FOR CONTROLLING THE POSITION OF A ROLLER OF SUCH A ROLLING MILL

This circular rolling mill (2) comprises a fixed main frame (4), a pair of cylindrical rollers (62), respectively internal and external, intended to shape internal and external radial faces of an annular part (P) and supported by a first secondary frame (46) mounted on the main frame, as well as a pair of conical rollers (82, 84), respectively upper and lower, intended to shape opposite front faces of the part (P) and supported by a second secondary frame (48) mounted on the main frame. At least one rack and pinion assembly (272-273, 274-275) is provided to move a roller in translation relative to one of the secondary frames (44, 48). At least one electric geared motor (172, 176, 178) is provided to drive the pinion (273, 275) of the rack and pinion assembly. The electric geared motor (172-178) is fixedly mounted relative to one of the auxiliary frames (46, 48). A fluid discharge mechanism (M72, M74) is interposed in a kinematic chain for transmitting force between the rack (272, 274)and the roller moved by t