Answer
Wave springs must be 'piloted' or guided to prevent buckling and ensure they remain concentric to the load axis. When a spring is piloted on a shaft (ID pilot), the designer must ensure the shaft diameter is smaller than the spring's ID at maximum expansion. Conversely, for a bore pilot (OD pilot), the bore must be larger than the OD at maximum expansion. Because wave springs expand radially when compressed, an OD pilot is generally preferred as it provides more stability for multi-turn springs. However, friction between the spring OD and the bore wall can lead to 'hysteresis' in the load-deflection curve. In high-speed assemblies, a 'shim-end' configuration is recommended for shaft piloting to provide a flat reference surface and prevent the end of the wire from digging into the shaft or mating component.
