A study on fundamental water lubrication characteristics of flat thrust bearing with partial water-repellent regions
A study on fundamental water lubrication characteristics of flat thrust bearing with partial water-repellent regions
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DOI：
10.1299/transjsme.20-00226
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
A. Takeuchi
中科院分区：
文献类型：
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作者：
A. Takeuchi
研究了部分斥水（滑动）型平面推力轴承的水润滑特性。在该轴承中，疏水（滑动）区域和亲水（非滑动）区域在滑动方向上交替排列，支撑载荷的压力由两个区域中剪切流率的不连续性产生。在滑移方向上的测量压力在疏水区增加，然后在亲水区减小，并且它与负载成比例地增加。基于无限宽轴承近似理论，分析了该轴承的基本润滑特性，并对实验结果进行了解释。在滑动长度较大的轴承表面上，剪切流率增加，并产生高压，从而产生较大的承载能力。然而，在大的滑移长度和薄的膜的条件下，抑制剪切流的滑移的压力流的影响增加，并且随着滑移长度的增加，载荷能力的增加程度变低。另一方面，对于大滑距轴承，在相同载荷下，油膜厚度增加，滑动面上的速度梯度减小，摩擦力趋于减小。然而，由于滑移长度的不同而引起的摩擦力的差异并不显著。由于在减小膜厚度的情况下摩擦力的增加程度低于负载能力的增加程度，因此摩擦系数随着膜厚度的减小而减小。特别是在薄膜区，摩擦系数突然下降。由于滑动对摩擦力的影响也很小，所以随着膜厚度变薄，由于滑动长度的不同而引起的摩擦系数的差异减小。该轴承中的滑动效应起到改善轴承特性的作用。
The water lubrication characteristic of partial water-repellent (slip) type flat thrust bearings was examined. In this bearing, water-repellent (slip) regions and hydrophilic (non-slip) regions were alternately arranged in the slip direction, and the pressure to support the load was generated by discontinuity of shear flow rate in both regions. The measured pressure in slip direction increases in the water-repellent region and then decreases in the hydrophilic region, and it increases in proportion to the load. The fundamental lubrication characteristics of this bearing were considered based on the infinite-width bearing approximation theory that can explain the experimental tendency. On bearing surfaces with large slip length, the shear flow rate increases and a high pressure is generated, resulting in a large load capacity. However, the influence of pressure flow that suppresses the slip of shear flow increases, and the degree of increase in load capacity with increase of the slip length becomes low, under the condition of large slip length and thin film. On the other hand, the film thickness increases and the velocity gradient on the slip surface decreases under the same load for large slip length bearing, so the frictional force tends to decrease. However, the difference in friction force due to the difference in slip length is not remarkable. Since the degree of increase in frictional force is lower than that in load capacity in case of decreasing film thickness, the friction coefficient decreases with decreasing film thickness. Especially, a sudden decrease of friction coefficient is shown in the thin film region. Since the effect of slip on frictional force is also small, the difference in friction coefficient due to the difference in slip length decreases as the film thickness becomes thinner. The slip effect in this bearing acts to improve the bearing characteristics.