全周边液压滑阀冲蚀形貌及性能演化特性

针对高端液压元件因滑阀冲蚀磨损引起阀口轮廓变动与性能不确定性问题，考虑颗粒物撞击阀口的概率事件，提出了基于Edwards冲蚀模型的全周边滑阀冲蚀圆角定量计算方法，并以阀控对称缸为例，揭示了四边滑阀各阀口冲蚀后的轮廓及阀特性的演化规律。研究结果表明，阀口的冲蚀圆角由颗粒物尺寸、颗粒物数量、撞击速度、阀口大小等因素直接决定；阀口流量越大、颗粒物数量越多、压差越大，颗粒物的撞击速度就越大；颗粒物尺寸相对阀口开度越大，颗粒物撞击阀口的概率就越大；在阀控缸动力机构中，液压缸的结构尺寸、运动速度、负载决定了各个阀口流量、压降和阀口开度。在负载恒定、液压缸恒速情况下，阀控对称缸4个阀口的流量相同但压降不同，冲蚀后的阀口圆角不一致。冲蚀导致滑阀压力增益降低，泄漏量增大，且产生零偏，零偏位移可通过惠斯通桥路平衡原理求出。

Erosion Morphology and Performance Evolution of Full-circumference Hydraulic Slide Valves

In view of the profile changes of valve port and performance uncertainty of the high-end hydraulic components caused by erosion of the slide valves， considering the probability of particle hitting the valve port, the quantitative calculation method of the erosion fillet of full-circumference opening slide valve was established based on the Edwards erosion model. Combined with the valve-controlled symmetric cylinder systems, the evolution law of four portss profiles and the characteristics of the four-sided slide valve after erosions were obtained. The results show that the erosion fillets are directly determined by the particle size, amount, impact velocity, valve opening and so on. The greater the valve port flowrate, the greater the amount of particles, the greater the pressure drop, the greater the impact velocity. The larger the size of particles relative to the valve opening, the greater the probability of particle hitting valve port. In the valve-controlled cylinders power mechanism, the size, speed and load of the hydraulic cylinder determine the flowrate, pressure drop and opening of the valve ports. Under the conditions of constant load and consistent reciprocating speed of hydraulic cylinders, the flowrate of the four valve ports of the valve-controlled symmetric cylinder is the same but the pressure drop is different, the fillets after erosion are inconsistent. Erosion results in the decrease of the pressure gain and increase of leakage of the slide valve, and the null bias occurs, the null bias displacement may be obtained by the balance principle of Wheatstone bridge.