Electro-hydraulic Proportional Pressure And Flow Characteristics Of The Composite Control Valve Research

With the rapid growth of China's economy, plastics products are being used widely ranging from civil area to industrial area. As the demand for their high quality and good outline is increasing, the hydraulic control system of molding machine must be able to offer accurate pressure and flow control at the same time to its injection system. The proportional pressure/flow hybrid valve (PQ valve),which adjusts pressure and flow rate simultaneously, is increasingly adopted for the hydraulic control system in molding machine, due to its advantages of high integration degree, stable and energy-saving performance. Based on the analysis of various types of PQ valve, this paper investigates the control performance of the BYL 16 series valve, including the static and dynamic characteristics.Chapter 1 gives an overview of the background and significance of the research theme, including the general situation of the hydraulic system in molding machine. The development of PQ valve has been introduced in detail as well.By studying structural principle of BYL PQ valve, its work principle is introduced in Chapter 2.Chapter 3 analyzes the static performance of BYL PQ valve by building its static model, and studies the disturbing ingredient that affects the static performance of PQ valve.Chapter 4 studies PQ valve's dynamic performance by building its dynamic model mainly based on its force balance and flow continuation. It offers the theoretical base and direction for further research.In chapter 5, based on theoretical analysis of PQ valve's dynamic performance, digital simulation has been done by using hydraulic dynamic simulation software DSH(digital simulation for hydraulic). It validates the legitimacy of theoretical analysis.In Chapter 6, the PQ valve's static and dynamic performance is studied through experiment. Resorting to the means of simulation and experiment, the comparatively proper parameters for the PQ valve system are obtained.The last chapter is the summary of this paper and the prospect for the future work.