极端工况下的高压柱塞马达密封环摩擦特性

为减少极端工况下因密封环摩擦磨损导致的疲劳断裂,保证马达的容积效率和可靠性。以法向正压力和剪切应力线性表示密封环摩擦力,并通过模态分析法和有限体积法分别研究系统多体动力学与缸孔内流体动力学,计算不同主轴转角、不同宽径比和弧面锥角下密封环的法向正压力和壁面剪切应力。研究结果表明:改变主轴转角引起的排量变化对摩擦力的影响较小;而密封环结构参数的变化影响明显,当宽径比小于0.3和弧面锥角小于1.8°时,摩擦力随宽径比和锥角增大而减小,在宽径比为0.3,弧面锥角为1.8°时摩擦力达到最小,最大缩减率分别为28%和25%;但当宽径比大于0.3和弧面锥角大于1.8°时,摩擦力随宽径比和锥角增大而增大;另剪切应力随着宽径比增大而增大;而受弧面锥角影响较小。研究结果为柱塞马达密封环减摩设计提供理论基础和依据。

Friction characteristics of piston ring of a high-pressure plunger motor under extreme working conditions

To reduce the fatigue fracture caused by the friction and wear of a piston ring and ensure the volumetric efficiency and reliability of a motor,the friction of the piston ring was expressed linearly with the normal pressure and shear stress,the modal analysis method and the finite volume method were used to investigate the multi-body dynamics of the system and the fluid dynamics in the cylinder bore respectively,and the normal pressure and wall shear stress of the ring under different spindle angles,different width diameter ratios and arc cone angles were calculated.The results show that the change of displacement caused by the change of spindle angle has little effect on the friction,while the change of structural parameters of sealing ring has obvious effect.When the ratio of width to diameter is less than 0.3 and the angle of arc cone is less than 1.8°,the friction decreases with the ratio of width to diameter and cone angle.When the ratio of width to diameter is 0.3 and the angle of arc cone is 1.8°,the friction reaches the minimum and the maximum reduction rate is 28%and 25%,respectively;however,when the aspect ratio is greater than 0.3 and the arc cone angle is greater than 1.8°,the friction increases the aspect ratio and the cone angle.In addition,the shear stress increases with the ratio of width to diameter,but it is less affected by the cone angle of the arc surface.The research results provide theoretical basis and scientific basis for the design of piston motor piston ring friction reduction strategy.