Small Opening Flow Linearity Optimization of High-Pressure and Large-Flow Two-Way Proportional Throttle Valve

As a key component of the die-casting machine, the flow linearity of the high-pressure, large-flow proportional throttle valve is a critical factor affecting injection accuracy at low openings. However, under existing main valve structures, flow linearity is typically nonlinear. To address this issue, this paper introduces a main valve structure designed to enhance flow linearity at low openings. Firstly, the working principle of the proportional throttle valve is explained, and the relationship between flow rate and spool displacement is calculated. Secondly, a finite element model of the proportional throttle valve’s main valve flow field is developed. The impact of four primary spool structures on flow linearity is examined, and a small rounded rectangular throttle orifice is proposed. Thirdly, the size of the spool orifice is optimized using an orthogonal test method, and the trend of how different structures’ orifice sizes influence flow linearity is investigated. Finally, a valve prototype is fabricated, and the optimization’s effectiveness is experimentally verified. The results of the throttle valve’s design and optimization provide guidance for future work.