Answer
In 'floating' bearing preload designs, the wave spring is used to take up axial play and maintain a constant load on the bearing races to prevent skidding. The spring must be installed so that it remains centered; otherwise, non-uniform loading can cause uneven wear. Pilots (either on the shaft or in the housing) are essential. The clearance between the spring ID and the shaft OD should be calculated as $C = (ID_{min} - OD_{shaft}) / 2$. If the spring is too tight, the radial expansion during compression will cause it to grip the shaft, resulting in a 'stuck' spring and loss of preload. Conversely, if the clearance is too large, the spring can shift off-center, leading to 'wave nesting' where the waves of different turns overlap, drastically changing the spring rate.
