CONTROLLING DEVICE FOR ROLL SHAPE IN ROLLING MILL

PURPOSE:To continuously change the deflections of rolls in the vertical direction in rolling the same material to be rolled, by specifically controlling a hydraulic pressure circuit of both cylinders, in a rolling mill having work rolls equipped with normal-reverse bending cylinders. CONSTITUTION:An electricity-hydraulic pressure servovalve 25, which performs a 4-way circuit controlling, is interposed between normal-reverse bending cylinders 13 and 14 and hydraulic pressure circuits 12. A port A of the servovalve 25 is connected to the cylinders 13 and 14, and a port B is connected to the cylinders 12 respectively; then the 4-way circuit control of the hydraulic pressure, introduced into a port P from a hydraulic pressure generating device 15, is made possible. A constant corresponding to an areal ratio of the cylinders 12 to the cylinders 13 and 14, is stored in a controlling device of the valve 25, to transmit an electrical signal corresponding to said constant to the valve 25. Accordingly, an resultant of external forces acting vertically, upward and downward, is continuously changed to the plus or minus direction, passing through the zero state of mutually balanced external forces.