Research On Traveling Wave Usm Using Cantilevel Type Bending Mode Sandwich-Transducer

Ultrasonic motor (USM) is a new-style actuator developed in recent thirty years. With so many advantages such as simple structure, flexible design, low speed, high torque, quick response, and non-electro-magnetic interference, the USM has been attracting intensive attention at home and abroad and widely applied in many fields, especially the traveling wave USM.This paper introduces a new structure of traveling wave USM, using bending sandwich-type transducer amplify ultrasonic vibration generated by piezoelectric ceramic, then through the cantilever the amplified vibration was transferred to the stator cylinder. There are tooth on the stator cylinder, which can further amplify the vibration amplitude on the stator cylinder. On the effect of traveling wave generated on stator cylinder. These tooth produce ellipse trajectory and drive the rotor. Then the rotor produces macroscopic motion. The traveling wave USM described in this paper has the following characteristics: 1, using sandwich-type transducer excite the bending vibration mode of cylinder, have high energy density; 2, the point to surface dynamic contact between rotor and stator is replaced by line to surface dynamic contact. Enlarge the contact area, and increase the output power; 3, By using the d33 mode of piezoelectric ceramics, electromechanical conversion efficiency can be improved.This article also designed cylindrical rotor conformed with the cylinder stator, the rotor can adjust the preload between the stator and rotor, also automatic compensate the gap between the stator and rotor, to resolve the problems that there are gaps between the stator and rotor during the USM is working.This article first introduces the basic structure of cylinder USM using sandwich-type transducer. Derived bending traveling wave equation in elastic objects, theoretically verify the feasibility of this type of motor structure. Then on the basis of initial structural parameters generated by theoretical calculation, this paper use the finite element analysis software ANSYS10.0 design the cylinder-type USM stator and the transducer have matched vibration mode. On this basis, Create the overall model of ultrasonic motors. By modal analysis, get the mode shape and the characteristic frequency of USM stator, and then by transient analysis, get the trajectory of tooth. Verify the feasibility of this type of USM structure in the simulation level.On the basis of theoretical analysis, manufacture the prototype of cantilever-bending-vibration-sandwich-transducer-type traveling wave USM, built an experimental platform to test the performance of ultrasonic motor's mechanical output, to verify the feasibility of this structure of USM. Combined with prototype production process and test data, analyze the adverse factors affecting motor functioning.