Grease

Grease

Grease is a semisolid lubricant grease are applied to mechanisms that can only be lubricant infrequently and where lubricating oil would not say in position. Grease –lubricated bearing have greater friction characteristics due to their high viscosity. The majority of rolling bearing are grease lubricated. Compared to oil, the advantage is that grease is more easily retained in the bearing arrangement against solid and liquid contaminants as well as moisture. The quantity of grease applied to a bearing depends on the application. Too little grease lead to metal to metal contact and premature failure. Excessive amount of grease cause at high speeds. Bearing wit seal or shield are filled with a sufficient amount of grease to provide long service life.

     The free volume in the housing should be partly filled with grease. Before operating at full speed, the excess grease in the bearing must be given time to settle during a running-in period. At the end of the running-in period, the operating temperature drops considerably. In application where bearing operate at very slow and good protection against contaminants and corrosion is required, its better to recommend filling the housing up to 90%wit grease.

Grease lubrication has certain advantages over oil lubrication and is a very efficient lubricant provided when correct type of grease is used. Grease lubrication has clear advantages over oil lubrication. Grease does not leak easily, it has sealing properties and it protect bearing surface from corrosion. Its disadvantage are grease life limitation and a limited cooling ability. Moreover, in some applications there is risk of grease starvation. Which leads to reduced lubricating films. However if the right grease, sealing system and/or lubrication system are chosen, then grease lubrication offers clear benefits.