• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文会议>Leeds-Lyon Symposium on Tribology; 19990914-17; Leeds(GB) >Shear-degradation of grease and base oil availability in starved EHL lubrication
【24h】

Shear-degradation of grease and base oil availability in starved EHL lubrication

机译：饥饿的EHL润滑中的润滑脂和基础油的剪切降解

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Experimental studies of starved grease lubrication show that, initially, the film thickness decays with time, as each overrolling displaces lubricant from the track. In earlier work the authors have modelled this condition and, assuming zero reflow, have obtained a power-law decay of film thickness with the number of overrollings. In the early stages the decay is as predicted, however as the test proceeds the film thickness sometimes recovers to a much higher value. This recovery of the film has important implications for the long-term operation of starved grease lubricated contacts. Film recovery is attributed to the shear degradation of the grease at the side of the track releasing 'base oil' which is thus available for reflow. In the starved condition the film thickness ultimately obtained is a function of the amount of lubricant present in the track and this amount is determined by the competing loss and replenishment mechanisms. The current paper proposes a model which links the shear degradation of grease at the side of the track with the amount of 'free' oil released. Close to the contact the grease experiences very severe conditions and the thickener matrix is progressively destroyed with each overrolling. This degradation results in base oil containing dispersed particles with a predominantly viscous character and thus provides the 'free' lubricant for reflow. In this paper starved film decay and recovery has been measured for three greases and the shear degradation behaviour characterised in a rotational viscometer. A model has been developed to describe the shear degradation of the grease and this has been coupled to an analysis of the shear rate conditions at the side of the Hertzian contact during overrolling. The predictions from the numerical model are compared to experimental measurements of starved film recovery.
机译：缺乏润滑脂的润滑脂的实验研究表明，最初，随着每次翻滚都会从轨道上移走润滑剂，薄膜厚度会随着时间而下降。在较早的工作中，作者对这种情况进行了建模，并假设回流为零，并且随着覆轧次数的增加，获得了薄膜厚度的幂律衰减。在早期阶段，衰减如预期的那样，但是随着测试的进行，薄膜厚度有时会恢复到更高的值。薄膜的这种回收对于饥饿的油脂润滑触点的长期运行具有重要意义。薄膜恢复归因于润滑脂在履带侧面的剪切降解，释放出“基础油”，因此可用于回流。在饥饿状态下，最终获得的薄膜厚度是履带中存在的润滑剂量的函数，该量由竞争性损失和补给机制决定。当前的论文提出了一个模型，该模型将润滑脂在轨道侧面的剪切降解与释放的“游离”油量联系起来。靠近接触处，润滑脂会经受非常严酷的条件，并且每次翻滚都会逐渐破坏增稠剂基体。这种降解导致基础油中的分散颗粒具有明显的粘性，从而为回流提供了“游离”润滑剂。在本文中，已经测量了三种润滑脂在饥饿状态下的薄膜衰减和恢复，并用旋转粘度计表征了剪切降解行为。已经开发了一个模型来描述润滑脂的剪切降解，并且该模型已与对过滚动过程中赫兹接触面的剪切速率条件进行了分析。将数值模型的预测结果与饥饿薄膜回收率的实验测量结果进行比较。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号