Preload Spring

A preload spring is a critical component in piezoelectric actuator assemblies designed to apply a constant compressive force to the piezoelectric stack or elements. This initial preload eliminates mechanical backlash, maintains electrical contact stability, prevents tensile stress during operation, and ensures consistent performance by keeping the piezoelectric material under compression even during dynamic cycling. It compensates for thermal expansion differences and mechanical tolerances within the actuator system.

The preload spring operates on Hooke's law (F = kx), where it applies a controlled compressive force to the piezoelectric stack. This force ensures the piezoelectric elements remain in constant contact with electrodes and mechanical interfaces, preventing separation during rapid expansion/contraction cycles. The spring maintains this force throughout the actuator's operational range, typically using coil, disc, or wave spring configurations calibrated to specific load requirements.