Method and device for measuring length of valve core of servo valve

As the length of a valve core of a servo valve is needed to know so as to accurately control the flow speed of liquid or gas in engineering, the invention provides a method and a device for measuring the length of the valve core of the servo valve at high precision, namely utilizing a step motor to control the moving direction and the displacement size of the valve core of the servo valve; measuring the direction and the size of the displacement of the valve core by a grating sensor and using the direction and the size of the displacement of the valve core as data in the x-axis direction; and recording the situation of the height change of a pneumatic micrometer floater along the displacement of the valve core and using the situation as data in the Y-axis direction. According to the obtained data, scattering dots are drawn in a rectangular coordinate system; and after data fitting, the length of the valve core of the servo valve can be obtained. The step motor has accurate control and reduces personal error a