What Is the Purpose of Bearings?
The main purpose of bearings is to prevent direct metal to metal contact between two elements that are in relative motion. This prevents friction, heat generation and ultimately, the wear and tear of parts. It also reduces energy consumption as sliding motion is replaced with low friction rolling.
They also transmit the load of the rotating element to the housing. This load may be radial, axial, or a combination of both. A bearing also restricts freedom of movement of moving parts to predefined directions as discussed above.