How much lubricating grease should be added to rolling bearings

Although lubricating grease is used to lubricate bearings, the more it is added, the better. Adding too much lubricating grease to the bearing is unnecessary and can increase friction, leading to an increase in temperature. However, if add too little grease, the oil film repair ability of the lubricating grease is not strong, which can deteriorate the lubrication state of the bearing. Therefore, it is important to determine the appropriate amount of lubricating grease to filling in the bearing.

Changes in lubricating grease in bearings

The lubricating grease inside the rolling bearing enters a stable distribution state after undergoing complex flow at the beginning. The small amount of flowing lubricating grease left in the friction area plays the main lubrication role, while the lubricating grease left in the outer cover itself does not flow, so it does not play a direct lubrication role. However, the lubricating grease left inside the outer cover serves as a seal to prevent the flowing lubricating grease left in the friction area from flowing out.

Selection of lubricating grease

The selection of lubricating grease should be based on the requirements of the engine. There is no need to use overly good lubricating grease on lower level engines, nor should lower level lubricating grease be used on higher level engines.

The general reference principle for the filling amount of lubricating grease in rolling bearings is as follows:

(1) Generally, bearings should not fill with lubricating grease, but should fill to 1/2-3/4 of the total space inside the bearing cavity.

(2) Horizontal bearings fill 2/3-3/4 of the inner cavity space.

(3) Vertically installed bearings fill 1/2 (upper side) and 3/4 (lower side) of the cavity space.

(4) In environments prone to pollution, for low-speed or medium speed bearings, all space in the bearings and bearing boxes should be filled.

(5) Before installing grease on high-speed bearings, the bearings should be place in a good lubricating oil. Generally, they should be soak in the base oil of the grease to avoid bearing burnout caused by insufficient lubricating grease on the friction surface during startup.

In summary, After running the bearings for a period of time, it is necessary to add lubricating grease.