Lubricants simultaneously perform many functions. Most obviously they reduce friction. They also transfer heat, prevent surface contact, dampen vibrations, inhibit rust, and spread the contact load over larger area. Improper lubrication is the most common cause of reducer failure. This can be improper oil selection, property break down or contamination...

There are 3 types of bearings: Rolling element, bushings, and journal. Antifriction bearings are commonly taken to refer to rolling element bearings. These bearing have rolling components, such as ball bearings. Lubrication is used to cool the surfaces, reduce friction and wear for the portion of sliding contact that occurs, and form a fluid film that distributes contact stress over a larger area. A hovercraft over water has a similar effect...

Combining Axial and Radial Forces Applied to a Bearing

Bearing life calculation is based on a single direction load. Calculating life for a bearing with both radial and axial forces applied requires combining them into a single equivalent load. These calculations seem complex reading manufacturers' catalogs. Each manufacturer presents their equations in differently. An individual manufacturer will present equations for each type of bearing they make differently. In reality the equivalent load equation is the same...