Interstage follow-up characteristics of displacement reverse follow-up proportional valve

Abstract

In the displacement follow-up proportional valve, the main spool moves with the pilot poppet, and the opening of the main valve port is limited by the stroke of the pilot spool, the flow amplification capacity of the main valve is restricted seriously. The displacement reverse follow-up proportional valve configuration with the displacement follow-up ratio exceeding 1 is proposed in this paper. The mathematical model is established to identify key factors affecting the stability of the main spool and the displacement follow-up ratio, and the main structural parameters of the proportional valve are determined. Subsequently, AMESim is employed to analyse the interstage follow-up characteristics under varying working conditions, and the accuracy of the simulation model is validated experimentally. The research results indicate that the dead zone of the pilot valve is 0.37 mm, and the main spool can effectively achieve reverse follow-up of the pilot poppet while maintaining a stable displacement follow-up ratio of approximately 1.2. When the inlet pressure exceeds 5 MPa, the step response rise time of the main spool is less than 10 ms, and the steady-state displacement follow-up error is below 5 %. Furthermore, the main spool can reliably track the pilot cylinder displacement sinusoidal input signal with a frequency below 20 Hz and the displacement lag time of less than 1 ms.