Large Capacity and High Speed Two-stage Hydraulic Servo Valve with a High Response Linear DC Motor and Its Application.

Abstract

The authors have been developing a high speed hydraulic servo valve (Linear Servo Valve, LSV), which has a dynamic response of a 90° phase lag at 500Hz and the rated flow of 40L/min, with a high response linear DC motor to improve the accuracy and the productivity of sheet metal machines. This paper describes a large capacity and high speed two-stage LSV used the LSV as a pilot valve and its application to a hydraulic turret punch press. The following points are obtained:(1) The two-stage LSV exhibits a dynamic response of a 90° phase lag at 100Hz. It is clarified that the dynamic response of the two-stage LSV is 25% higher than that of the conventional three-stage hydraulic valves.(2) High ram speed of the hydraulic turret punch press, 2times higher than that of the conventional machine using the three-stage hydraulic servo valve, has been realized by adopting the two-stage LSV.(3) The hydraulic turret punch press using the two-stage LSV is able to reduce the power consumption to 91% in comparison with the conventional machine using the three-stage hydraulic servo valve.