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采用光干涉法相对光强原理对点接触中心区进行了润滑膜厚度测量,该方法在垂直方向的分辨率可达0.5nm,水平方向可达1μm。讨论了膜厚与压力,速度和润滑油粘度之间的关系,观察和分析了流体润滑膜的失效现象。实验结果表明如果接触压力足够小或者润滑油粘度足够高,即使在一个很低的速度下也能清晰地观察到流体动压润滑效应。当压力增至某一定值,在膜厚-速度曲线上可观察到一个转折点,当速度降到此点以下时,润滑膜厚度将很快减小到几个分子层厚,此时,润滑膜不再具有流体润滑特征,即流体润滑膜失效。对不同粘度的润滑剂,失效点会出现在不同的速度和压力下。要使接触区在较高的压力下形成流体膜就必须施加更高的速度或使用更大粘度的润滑油。最后建立了失效点的压力、速度和润滑油粘度之间的关系。
Using the principle of relative light intensity of light interference method, the thickness of lubricant film was measured in the central area of point contact. The resolution of this method can reach 0.5nm in the vertical direction and 1μm in the horizontal direction. The relationship between film thickness and pressure, velocity and oil viscosity was discussed. The failure phenomenon of fluid lubrication film was observed and analyzed. The experimental results show that the hydrodynamic lubrication effect is clearly observed even at a very low speed if the contact pressure is small enough or the viscosity of the lubricant is high enough. When the pressure increases to a certain value, a turning point can be observed on the film thickness-speed curve. When the speed drops below this point, the thickness of the lubricating film will be quickly reduced to a few molecules. In this case, the lubricating film No longer have the characteristics of fluid lubrication, fluid lubrication film failure. For different viscosity of the lubricant, the failure point will appear at different speeds and pressures. To make the contact zone to form a fluid film at a higher pressure, higher speeds or larger viscosity oils must be applied. Finally, the relationship between pressure, velocity and oil viscosity of failure point is established.