Evaluation of shape memory alloy bulk actuators for wear compensation in ball screw drives

In this paper we present an approach to reset a preload loss in ball screw drives which enables to compensate losses of positioning accuracy due to wear over lifetime. The main purposes are reduced maintenance, longer service life and improved workpiece quality by regenerating the desired preload conditions which leads to a higher profit for manufacturers. For this purpose, a novel shape memory alloy (SMA) bulk actuator module for ball screw drives is designed. The device is developed to be implemented in standard drives without major changes in component design. It is installed between flanged nut and counter nut and replaces a spacer usually needed to set a defined preload. To achieve the required actuator performance SMA bulk actuators are investigated in detail. This covers their basic design and activation concepts. A prototype is designed and experimentally investigated; measurements show the proof of the concept.