Establishment of method to observe EHL film thickness and its behavior in commercial steel rolling bearing by ultrasonic interference method

为保证恶劣工况下滚动轴承的稳定运行，研究轻微固体接触条件下的EHL膜厚度及其行为具有重要意义。因此，仅仅通过常规的光学观察是不够的，必须明确不传输光的真实滚动轴承的EHL区域的润滑条件。本研究的目的是提出一种超声脉冲反射法测量100 nm以下EHL膜油膜厚度的新方法，并建立一种新的测量系统来观察商用钢轴承EHL膜厚度及其行为。用50MHz测头在常压下测得的超声波反射特性与油膜厚度的关系符合超声辐照区回波高度平均的理论结果。此外，还测量了已知膜厚下回波高度的关系，并绘制了相应的曲线和校正曲线。在静态条件下用该校准曲线估计膜厚时，可以清楚地看到，可以估计小于100nm的膜厚。用光学玻璃和钢球组成的单核细胞型EHL仪用超声波法观察到的形状在回波高度上的分布与光干涉法观察到的EHL膜的形状定性一致。当用钢盘进行类似实验时，可以观察到通常用光干涉法观察到的马蹄形油膜。此外，速度和载荷对EHL膜形成的影响符合一般趋势，并证实了超声波法测量EHL膜厚度的可能性。此外，观察了薄膜厚度直到与推力轴承装置直接固体接触开始时的行为，推力轴承装置具有停止滚珠旋转的功能，可以评估商用滚动轴承的润滑条件。结果证实，商用轴承的EHL膜厚分布行为与扁钢盘观察到的行为相同。如上所述，证实了超声波法评价商用轴承EHL润滑条件的可能性，为技术开发奠定了基础。少

For the stable operation of a roll bearing operated with severe condition, it is important to observe an EHL film thickness and its behavior under the condition that solid contact slightly occurs. Therefore, it is insufficient only by conventional optical observation and must clarify the lubrication conditions of EHL region for real roll bearing which does not transmit the light.The purposes of this study were proposal of a new measurement method of oil film thickness for the EHL film less than 100 nm by ultrasonic pulse reflection method, and establishment of the new measurement system which can observe the EHL film thickness and its behavior for commercial steel bearing.Relations of reflection characteristic of ultrasonic wave, measured under atmospheric pressure with 50MHz probe, and the oil film thickness accord with the theory result which is made echo height average in ultrasonic wave irradiation area.In addition, the relations of echo height for a known film thickness were measu … More red and calibration curves were made. When the estimation of a film thickness under the static condition with this calibration curve was done, it became clear that film thickness estimation of less than 100nm can be possible.The distribution of the shape in echo height observed by a ultrasonic wave method with the monocyte type EHL apparatus, which consisted of optical glass and a steel ball, agreed with the shape of EHL film observed by light interference method qualitatively. When the similar experiment using steel disc was performed, the horseshoe-shaped oil film, which is generally observed by light interference method, was able to observe. In addition, the influence of speed and load for the formation of the EHL film accorded with a general tendency, and the possibility of the EHL film thickness measurement by a ultrasonic wave method was confirmed.Furthermore, the behavior of a film thickness until direct solid contact start with a thrust bearing apparatus, which has a function stopping the revolution of balls and can evaluate lubrication conditions of a commercial roll bearing, was observed. As a result, it was confirmed that the behavior of EHL film thickness distribution of a commercial bearing was same with the behavior observed by a flat steel disc.As mentioned above, the possibility of the evaluation of EHL lubrication conditions for the commercial bearing by an ultrasonic wave method was confirmed, and the base for technology development was established. Less