This document is a summary of Lubrication for （本文档是一个总结的润滑）.pdf

Phone: +61 (0) 402 731 563 Fax: +61 (8) 9457 8642 Email: info@ Website: This document is a summary of ... Lubrication for Journal Bearings Introduction The objective of lubrication is to reduce friction, wear and heating of machine parts that move relative to each other. Types of lubrication Five distinct form of lubrication may be identified: 1. Hydrodynamic 2. Hydrostatic 3. Elastohydrodynamic 4. Boundary 5. Solid film Hydrodynamic lubrication suggests that the load-carrying surfaces of the bearing are separated by a relatively thick film of lubricant, so as to prevent metal to metal contact, and the stability thus obtained can be explained by the laws of fluid mechanics. Hydrodynamic lubrication depends on the existence of an adequate supply of lubrication at all times rather than having lubrication under pressure. The film pressure is created by moving surface itself pulling the lubricant into a wedge-shaped zone at a velocity sufficiently high to create the pressure necessary to separate the surfaces against the load on the bearing. Hydrostatic lubrication is obtained by introducing the lubricant (can be air, water) into the load-bearing area at a pressure high enough to separate the surfaces with a relatively thick film of lubricant. In contrast to hydrodynamic lubrication, this kind of lubrication does not require motion of one surface relative to another (applicable when velocities are small or zero, where the frictional resistance is absolute zero). Elastohydrodynamic lubrication is the phenomenon that occurs when a lubricant is introduced betw