How does the 'radial expansion' phenomenon affect wave spring design in tight bore applications?

As a wave spring is compressed, the wave peaks flatten, causing the mean diameter $D_m$ to expand radially. The expansion can be estimated using the formula $\Delta D = 0.02 \cdot \frac{(L_f - L_w)}{N}$, where $L_f$ is the free height and $L_w$ is the work height. If the clearance between the spring's outer diameter and the bore is insufficient, the spring will bind, leading to erratic load-deflection behavior and potential galling. High-precision designs in automotive transmissions require calculating this expansion to ensure the spring remains free-floating throughout its operational stroke.