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1、博博 士士 学学 位位 论论 文文 论文题目论文题目 纵扭复合型超声波电机的若干问题研究纵扭复合型超声波电机的若干问题研究 作者姓名作者姓名 龚书娟龚书娟 指导教师指导教师 郭吉丰郭吉丰 教授教授 学科学科(专业专业) 电机与电器电机与电器 所在学院所在学院 电气工程学院电气工程学院 提交日期提交日期 二零零五年五月二零零五年五月 申 请 博 士 学 位 论 文 DISSERTATION SUBMITTED FOR DOCTORIAL DEGREE OF PHILOSOPHY 纵扭复合型超声波电机的若干问题研究 STUDY ON SOME PROBLEMS OF THE HYBRID LONG
2、ITUDINAL-TORSIONAL ULTRASONIC MOTOR BY 龚 书 娟 GONG SHUJUAN 导 师 SUPERVISOR 郭吉丰 教授 PROF. GUO JIFENG 浙江大学电气工程学院 COLLEGE OF ELECTRICAL ENGINEERING ZHEJIANG UNIVERSITY May 2005 浙 江 大 学 博 士 学 位 论 文 纵 扭 复 合 型 超 声 波 电 机 的 若 干 问 题 研 究 摘 要 论文概述了超声波电机的发展简史、基本原理、特点和分类，介绍了驻波型超 声波电机的发展情况，特别是纵扭复合型超声波电机研究进展，重点论述了纵扭复
3、 合型超声波电机的结构调谐、接触模型、噪声这三个重要问题，并提出了一些研究 思路，明确了本文的主要研究内容。 介绍了纵扭复合型超声波电机的基本原理和结构，并应用 Mason 机电等效法， 推导出了纵扭复合型电机的纵、扭转振动谐振频率方程，建立了纵扭复合型超声波 电机关键尺寸与谐振频率的关系，从而形成了纵扭复合型超声波电机的基础理论。 首次提出了一种具有中空结构的纵扭复合型超声波电机，其原理是利用了一阶 扭振动和一阶径向振动（引起的纵向振动） ，这种电机具有调谐方便，结构简单和电 机轴向尺寸小等优点，文中详细地用有限元法和实验结果阐述了其振型及其调谐思 路，并就结构尺寸和电机压紧力对电机谐振频率
4、的影响进行了具体分析. 提出了纵扭复合型超声波电机的力传递模型和特性分析方法。首先，采用一振 动周期内轴向冲量守恒的原理推导给出了定转子接触角关系式，并对摩擦力模型进 行了改进，随后运用一振动周期内周向能量守恒的原理推导了电机输出力矩表达式， 分析了堵转力矩和空转转速的影响因素，并给出了电机接触面的传递效率。利用上 述表达式，仿真和实验分析了定转子预压力对电机输出力矩的关系和影响，以及其 他参数对接触面效率的影响，解释了这种电机工作效率偏低的原因。 深入地分析了纵扭复合型超声波电机定转子纵振动的耦合问题，结合电机定转 子的实际运转过程情况，运用振动理论建立了纵振动耦合简化模型，分析定转子各 种
5、复杂的振动过程和系统参数对纵振动的影响，从理论和实验证实了力传递模型建 立中的假设合理性，为电机设计提供了理论基础。 实验研究了纵扭复合型超声波电机的噪声机理，通过各种噪声实验和有限元法 分析比较，最终确认纵扭复合型超声波电机的噪声是由二部分组成，一是由系统运 动的非线性产生的分数次谐波诱发的噪声，且是主噪声源；二是由摩擦激发的定、 转子低阶谐振产生的幅射噪声，这为电机结构改进和降低噪声提供了依据。 关键词: 超声波电机、纵扭复合型、模态分析、调谐、有限元、力传递模型、 纵振动耦合模型、噪声、机械特性 I 摘 要 ABSTRACT The developing history, basic p
6、rinciple, characteristics, and classification of the ultrasonic motor is stated briefly, the evolvement of the standing-wave, especially the hybrid longitudinal-torsional ultrasonic motor is introduced, the following three problems are discussed mainly: mode degeneracy and structure, contact model a
7、nd noise, Thus the research content is confirmed. The basic principle and structure of the hybrid longitudinal-torsional ultrasonic motor is introduced, the resonance frequency equations of longitudinal and torsional vibrations of ultrasonic motor using the Mason equivalent circuit are deduced,The r
8、elationship between physical dimension and the resonance frequency is given. The design theory of longitudinal and torsional vibrators is founded. A-new-hollow-structure hybrid longitudinal-torsional ultrasonic motor is put forward which takes use of the first-torsional-vibration-mode and the longit
9、udinal-vibration-mode caused by first-order-radial-vibration in designing of this kind of motor to realize mode degeneracy, which has many characteristics, such as, convenient mode degeneracy, small-axial-scale and high-torque; the frequencies and modes of longitudinal vibration and torsional vibrat
10、ions as well as the relations between structure and frequency are given by FEM and experiments. The force transfer model and analytical method of the characteristics is put forward for the first time. First of all the relationships between the contact angle, preload, and physical parameters of frict
11、ional materials are given according to the impulse conservation law axially, the model of frictional force is improved on, then the equations describing output torque, amplitudes of longitudinal and torsional vibration, and parameters of the rotor are derived according to the principle that the work
12、 done by the load is equal to that by the driving force in one vibrating cycle. all factors that influence the maximum torque and no-load speed is analyzed, the formula for transfer efficiency on the stator/rotor interface is deducted, the relationship between the preload and output torque and the e
13、ffect on the transfer efficiency on the stator/rotor interface of other parameters according to the above formula is given, the low-efficiency of this type motor is explained. The coupling problem of longitudinal vibration of the hybrid longitudinal- torsional ultrasonic motor is probed, the simplif
14、ied coupling model of the longitudinal vibration combining the running circumstance of the motor is founded. The complex vibrations of stator and rotor and the effect on the longitudinal vibration of system parameters is II 浙 江 大 学 博 士 学 位 论 文 纵 扭 复 合 型 超 声 波 电 机 的 若 干 问 题 研 究 analyzed, the rational
15、ity of the assumption of the force transfer model is verified, theory basis for the design of motor is provided. The noise is analyzed by experiment and FEM, the conclusion is: there are two kinds of noise. First, nonlinearity of the system induces the fractional harmonic which roots in the noise; s
16、econd, the low-frequency-vibration noise of the rotor is excited by friction. The study can be useful for reducing the noise and remodeling the structure of the motor. Key words: ultrasonic motor, longitudinal-torsional, mode analyzing, mode degeneracy, FEM, force transfer model, coupling model of longitudinal vibration, noise, mechanical characteristic. III 目 录 目 录 第一章 绪论1
