This paper presents a disc-type ultrasonic piezoelectric motor, which is designed for micro flying vehicles. It provides high output rotation speed under low operating voltage, compared with common devices, by employing “contact teeth” wave transmission structure. The motor (USM) consists of trimorph disc stator, triple internal contact teeth, shaft and two hemispheric hard-wearing rotors. prin...

An SiCf/SiC composite has the following excellent properties: high strength, low specific gravity, and temperature resistance, which great prospects in combustion chamber of rockets or aero engines. Hole-making parts is an important processing method. Generally, water-based oil-based coolants are avoided, so dry drilling primary hole-making approach for SiCf/SiC. However, abrasion resistance ha...