基于光纤位移传感器的轴承最小油膜厚度测量方法的理论分析.doc

基于光纤位移传感器的轴承最小油膜厚度 测量方法的理论分析 摘要：基于光纤传感器的优点和间接测量油膜厚度方法的实用性，本文从理论上深入地探讨了用光纤位移传感器间接测量圆轴承润滑油膜最小厚度的方法：两点测量法和三点测量法。通过详细的测量方案设计以及深入的误差理论分析，最后得出：两点测量方法的理论测试精度较高，其最小厚度的绝对误差为1.5‰δ，位置角的绝对误差约为0.08594°，适合测试精度要求不高的场合；三点测量方法的理论测试精度为最高，其相应各参数的测量误差为零。 关键词：最小润滑油膜厚度； 两点测量法； 三点测量法； 光纤传感器； 误差分析 The principle Analysis of Measurement Approaches for the Least Lubricating Film Thickness of Slide Bearing Based on Fiber-Optical Displacement Sensor Qin Ying, Zhang Xiaodong (School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049,China） Abstract: Based on the advantage of fiber-optical sensor and the practicability of indirect measurement for the least lubricating film thickness, the indirect measurement approaches for the least lubricating film thickness of slide bearing using fiber optic sensor are deeply discussed in theory in the paper, which include in the two-point measurement approach and the three-point measurement approach, respectively. Through the detail design of their measurement plans and the deep principle analysis of measurement error, it is obtained that the two-point measurement approach can be used for the relative lower accuracy situation with 1.5‰δ absolute error for the least lubricating film thickness and 0.08594°absolute error for the location angle, and the principle measurement accuracy of the three-point measurement approach is the highest with 0 error for the relevant parameters. Keywords: The Least Lubricating Film Thickness; Two-point Measurement Approach; Three-point Measurement Approach; Fiber-optical Sensor; Error Analysis. 1.引言( 在高速、重载、高温条件下工作的机器，摩擦、磨损是其发生故障的最主要原因。严重的干摩擦会导致轴承温度和润滑油温度上升，黏度下降，承载能力降低，从而酿成粘瓦、烧轴等恶性事故。润滑则是减少摩擦与磨损有效的方法；机械零件的润滑分为边界润滑，流体润滑；流体润滑又有气体润滑、液体静压润滑和液体动压润滑；液体动压润滑，是由摩擦面间的相对运动，使收敛形缝隙中的粘性液体产生压力，用以平衡外载荷，并使液体形成足够厚的油膜将两摩擦表面完全隔开。液体动力润滑在工业中有很重要的作用，比如汽车、飞机、火车、船舰及其他一些大中小型的机械设备都离不开液体动压润滑。轴承间隙的合理数值是滑动轴承产生油膜厚度的必要条件，为保证轴承处于液体动力润滑状态，必须满足最小油膜厚度处轴承两表面不平度高峰不直接接触的条件。工程中对轴承间隙，只规定最小间隙值，而对最大间隙值，由加工公差决定，因此对最小油膜厚度的研究非常重要。 最小油膜厚度的测量方法，五六十年代在国内外采用的有电阻法