Evaluation of a surface acoustic wave motor output force

Evaluation of optimum pressing force, namely pre-load for a slider to obtain superior operation condition of a surface acoustic wave (SAW) motor is described. As a first experiment, we used steel balls for sliders. The steel balls that we used were 0.5, 1 and 2 mm diameter to change contact conditions such as contact pressure, contact area and deformation of the stator and the slider. As a result, the deformation of the stator and the slider by the pre-load should be half of the normal vibration amplitude. This condition was independent to the diameter of the balls. The maximum driving force was 0.95 mN and the driving force density was 50 N/mm². Secondly, in order to enlarge the contact area, multi contact points slider was made on trial. As a result, the driving force became 25 mN, 25 times as high as the first result, 0.95 mN. The SAW motor has high potential to be a large output force, quick response, long traveling distance and low in profile micro linear actuator