Preparation and characteristics study of a direction-dependent texture for an ultrasonic motor stator

Purpose Ultrasonic motors (USMs) often experience significant wear and temperature rise of the friction materials. This study aims to present a solution involving direction-dependent textures on the stator surface to improve mechanical performance and reduce wear. Design/methodology/approach The friction material’s adhesion area was first measured to guide the laser texturing process. A direction-dependent texture on the stator surface of the USM was innovatively designed and fabricated via laser processing. The textured surface was then systematically evaluated through mechanical performance tests, efficiency measurements and temperature rise analysis, while the surface morphology and wear evolution were quantitatively characterized throughout the testing process. Findings Experimental results showed that the textured stator improved no-load speed by 6.19% in clockwise rotation, although it decreased by 2.27% in reverse. Maximum operational efficiency dropped by 14.32 and 28.86% for clockwise and reverse rotations, respectively. Notably, the textured stator enhanced wear resistance of the PTFE-based friction material, with thickness reductions of 77.00 (clockwise) and 63.17% (counterclockwise). After 35 min of operation, the temperature increase in the textured stator was only 0.9°C lower than the nontextured version. Originality/value The novel direction-dependent surface texture developed in this study demonstrates significant performance enhancement in traveling wave USMs, establishing its potential as an innovative stator design solution.