针杆不同倾斜状态下狭缝型气浮轴承静特性分析

Static Characteristic Analysis of Slit Type Gas Bearing at Different Needle Bar Tilting States

缝纫机针杆在实际运动过程中在复杂力作用下会发生倾斜,为研究针杆倾斜状态对轴承气浮特性及气体对针杆的影响规律,通过建立针杆倾斜下的物理模型,分别拟合上下轴套气膜高度曲面,基于Mat Lab利用有限差分法计算气膜压力分布,分析气浮轴承的静特性。结果表明:针杆倾斜角度越大,承载力越大,气体对针杆产生的反力矩也越大;上下轴套气膜差异明显,上轴套气体刚度大,若针杆高速运动将会产生动压效应。

The sewing machine needle bar will tilt under complex forces in the actual movement process. In order to study the influence of the needle bar inclined state on air flotation properties of bearing and the influence of gas on the nee- dle bar, the physical model of needle bar tilting was established, the gas film height surface of upper and lower bushings was simulated. The pressure distribution of gas film was calculated based on MatLab and by using the finite difference method, and the static characteristics of gas bearing were analyzed. The results show that, the larger the tilt angle of needle bar, the bigger the flotation capacity, the greater the countertorque produced by gas on the needle bar. The difference of gas membrane between upper and lower bushings is obvious, the upper shaft has gas big stiffness, and a dynamic pressure effect will generate if the needle bar is in high speed movement.