Research On The Technology Of Piezoelectric Transducer Used To Ultrasonic Bearing

Gas bearings are widely used in engineering fields micromachining, precision engineering, medical devices, etc.. With gas lubricated and ultrasound studies suspension technology progressing, high-speed, high-precision, low friction and non-contact gas squeeze film bearings become a new research direction in this technical field. Ultrasonic suspended squeeze film bearing is developing towards multi-dimensional, dynamic direction based on the one-dimensional flat static suspension. High efficiency piezoelectric transducer, which is called piezoelectric extruder, is a key component member of the ultrasonic bearing.This paper presents a radial tolerance squeeze piezoelectric transducer used to the new type ultrasonic suspension squeeze film bearing. When the piezoelectric transducer vibrates in the style of radial coupled, establishing electromechanical equivalent circuit mathematical model of coupled radial vibration, and carrying vibration characteristics of transducer finite element simulation analysis and experimental verification. The main work is as follows:Structurally, the piezoelectric transducer is composed by a thin-walled metal cylinder and a rectangular piezoelectric ceramic sheets. There are supporting bases and rectangular grooves on the outer surface of metal cylinder. The structure satisfies the condition of the radial enclosed space formed between a thin film acoustic levitation bearing and shaft, increasing the radiation area, reducing friction, improving the stability of the suspension, rotation accuracy, efficiency, and so on.Theoretically, with the theory of piezoelectric ultrasonic vibration and the electromechanical analogy method, structuring the system’electromechanical equivalent circuit mathematical model of radial vibration, building the radial vibration electromechanical equivalent circuit of piezoelectric transducer, and computing composite piezoelectric transducer’resonant frequency equation of this kind. With the help of Matlab software, calculating some vibration parameters, such as resonant frequency and anti-resonance frequency, of the transducer whose designed size is known. Combined with the piezoelectric coupling finite element theory in ANSYS software, doing the modal and harmonic response analysis for the transducer and getting the optimum vibration form, resonant frequency, anti-resonance frequency and the maximum amplitude of radial when the piezoelectric transducer is in a squeezed triangle shape, concluding the relationship of the resonance frequency of piezoelectric transducer and its materials, structure size.Combined with numerical analysis and orthogonal test method, studying the influences of piezoelectric transducer materials and structure sizes on resonance frequency and the maximum amplitude of radial. With the purpose of optimizing the performance of mechanical vibration transducer, optimizing the transducer structure size; Producting piezoelectric transducer prototype and ultrasonic bearing suspension system, testing resonant frequency and the radial amplitude of transducer, verifying the correctness of the theoretical calculation and finite element analysis results.