考虑节流形式的液体静压导轨油膜动刚度建模研究

Research on Oil Film Dynamic Stiffness Modeling of Hydrostatic Guideway Considering Orifice Form

液体静压导轨的动刚度性能直接影响着机床的加工精度。为分析不同节流形式下液体静压导轨的动刚度变化趋势,分别选取固定液阻、可变液阻与无液阻节流,建立液体静压导轨的承载力与动刚度模型。当导轨使用固定液阻或可变液阻节流时,导轨承载力F随初始阻尼比的增加而减小,随油膜厚度变化率ε的增加而增大;导轨动刚度s随初始阻尼比的增加逐渐呈现明显的峰值,且该峰值随初始阻尼比的增加逐渐向较大的油膜厚度变化率ε方向移动;在相同条件下,可变液阻节流在较小的油膜厚度变化率ε下能获得较大的导轨承载力F与导轨动刚度;无液阻节流时,导轨刚度与导轨承载力随压力比、油膜厚度变化率ε的增大呈单调递增。

The dynamic stiffness of the hydrostatic guide has a direct impact on the machining precision of the machine.In order to analyze the dynamic stiffness of the hydrostatic guide under different orifice form, choosing the fixed liquid resistance, variable liquid resistance and non-resistance, the liquid hydrostatic guide bearing capacity and dynamic stiffness model was established. When the guide rail using a fixed liquid resistance or variable fluid throttling, the bearing capacity F of the oil film decreases with the increase of the initial damping ratio λ0, the bearing capacity of the oil film increases with the increase of the film thickness change rate ε;the dynamic stiffness s increases with the increase of the initial damping ratio λ0, and the peak gradually moves toward the larger oil film thickness change rate ε with the increase of the initial damping ratio λ0;under the same conditions, the variable orifice throttle can obtain a large bearing capacity and oil film dynamic stiffness at a smaller oil film thickness change rate ε;when quantitative oil supply is used, the guide stiffness and bearing capacity increase monotonically with the increase of pressure ratio λdl and oil film thickness compression rate ε.