LIQUID PRESSURIZING DEVICE

Japanese Patent JP3822362

B2

PROBLEM TO BE SOLVED: To accurately converge a discharge pressure to a target pressure in a short time by controlling an actual discharge pressure and determining an optimum feed speed after a plunger is moved and the actual discharge pressure is attained to a preliminarily fixed threshold value and subsequently maintaining the optimum feed speed to be constant. SOLUTION: Before an operation of a liquid pressurizing device provided with an injection part 17 performing a material cutting by high pressure liquid injection, a pressure set value Ps and threshold values α, β are inputted into a control part 25 at first. Next, a servo motor 7 is driven, plungers 5 (5A, 5B) are reciprocated, an actual pressure value P is detected by a pressure sensor 23 for every prescribed time and whether P attains Ps-β or not is decided. When this decision result is NO, a speed command signal making feed speed of the plungers 5 Vmax is generated. When P attains Ps-β, a proportional control of the pressure value P is performed while the plungers 5 attain stroke ends at first and subsequently, feed speed when the directions of the plungers 5 are changed is set to optimum feed speed.