力反馈电液伺服阀反馈小球磨损特性研究

Study on wear characteristics of feedback ball in force feedback electro-hydraulic servo valve

为了得到力反馈电液伺服阀反馈小球磨损深度与伺服阀工作状态间的关系,建立了反馈小球的力学模型和运动学模型,基于Archard黏着磨损理论得到了小球磨损量计算模型,并分析了温度和配合形式对磨损的影响.研究结果表明:小球磨损会破坏力反馈组件的平衡状态,降低反馈力并引起输出非线性,非线性区域宽度与磨损深度成正比;温升会导致小球与阀芯变成过盈配合,产生附加的接触压力与温升大小呈二次函数关系,加剧小球的磨损;当采用球槽配合形式时,小球磨损包括切向滑动磨损和周向转动磨损,阀芯在阀套内转动引起的周向磨损是小球磨损的主要原因;球孔配合形式可以避免阀芯的周向转动,从而有效地降低小球的磨损;实验结果和理论结果一致,可以为伺服阀的磨损量预测、故障诊断提供依据.

To obtain the relationship between the feedback ball wear depth of the force feedback electro-hydraulic servo valve and the working state of the servo valve,the mechanical model and kinematic model of the feedback ball were established.The calculation model of ball wear volume was obtained based on Archard adhesion wear theory,and the influence of temperature and assembly form on wear was analyzed.Results show that wear of the ball will break the balance of force feedback component,and reduce the feedback force,resulting in nonlinear output.The nonlinear region width is proportional to the wear depth.Temperature rise will lead to interference fit between the ball and the spool,and the generated contact force has a quadratic function relation with the temperature rise,which will aggravate the wear of the ball.When the ball in slot assembly form is adopted,the wear includes tangential sliding wear and circumferential rotational wear,and the circumferential wear caused by the rotation of the spool in the valve sleeve is the main reason for the ball wear.The ball in hole assembly form can avoid the spool rotation and reduce the wear of the ball effectively.Experimental results are consistent with the theoretical results,which can provide the basis for the wear prediction and fault diagnosis of servo valves.