The internal clearance of a bearing is a product of the stack up of component geometries within the bearing. It is the measure of the free movement within the ball bearing, sometimes referred to “play” or “slop.”
Internal clearance has a direct impact on bearing performance and eventually the bearing life. A reduced clearance can increase heat generation while an increased clearance can generate unwanted vibrations. Therefore, a careful consideration must be made when selecting a bearing internal clearance to maximize the bearing performance.
Some manufactures use ball selection to achieve the designed internal clearance while others standardise the ball size and match the bearing races – the former being the most common method. It’s the measure of displacement of the inner ring and outer ring with respect to each other, both in the radial and axial directions.