一种纵扭复合换能器型超声马达的原理及实验研究

本文从纵扭振动换能器理论出发，计算了一种新的复合换能器型超声马达，并进行了实验研究，测出了其主要性能参数。     

直线超声马达实验

本文介绍了直线超声马达的结构，原理和实验内容。     

纵振驱动球面弯曲振动超声聚焦系统的聚焦特性*

为了将超声聚焦效应应用于工业加工中的冷却技术中,该文提出一种由夹心式换能器纵向振动驱动球面弯曲振动超声聚焦系统。基于基尔霍夫-亥姆霍兹声场理论分析了由换能器中心面纵向振动和球面弯曲振动组成的复合超声振动条件下的声场聚焦特性,并通过实验进行验证。研究结果表明,该聚焦系统具有显著的聚焦特性,球面弯曲振动将声能汇聚在声场焦区;当声场相位相同时,换能器中心面纵向振动和球面弯曲振动产生的声场在焦区发生叠加,可以进一步提高焦区声压;减小换能器中心面半径和球面曲率半径、增加球面开口半径可以增强复合超声振动的聚焦效果。     

双激励纵弯耦合宽带复合棒水声换能器

为研究进一步拓宽双激励复合棒水声换能器的工作带宽方法。利用等效电路法和有限元方法研究了双激励换能器的振动模态,分析了中间质量块的材料、长度对换能器发射电压响应的影响,提出结合较低工作频段的纵向振动和较高工作频段的纵向振动与径向振动耦合引起的弯曲振动进一步展宽带工作频带的方法。根据优化参数后的仿真模型制作的样品工作频带为14 kHz～47 kHz。采用这种纵弯振动模态耦合的方法可以有效拓宽双激励宽复合棒换能器的工作带宽。     

一种驻波型超声马达的研究

研制出一种以长条片关压电陶瓷振子作煊子的驻波型超声马达，该马达具有整体结构简单，易于制作与调整、驱动电路合理、运行稳定的特点；由实验研究，测出了其主要性能参数，利用该马达已开发出特性优异的超声步进马达及时钟模型，小型走纸机。     

纵-扭复合振动模式指数型复合超声变幅杆的研究

本文对指数型纵－扭复合振动模式的复合超声变幅杆进行了理论及实验研究，该变幅杆由均匀截面直棒及指数型截面杆组成。文中推出了变幅杆中纵向振动及扭转振动的共振频率方程，通过发迹指数型变截面棒的截面变化规律，实现了同一变幅杆中纵向振动与扭转振动的同频共振。     

夹心式纵-扭复合模式压电超声换能器的共振频率

本文对夹心式纵-扭复合振动模式压电超声换能器进行了研究．从换能器的等效电路出发，在无耦合时，得出了换能器中纵向振动模式及扭转振动模式的各自共振频率方程．实验表明，换能器各自共振频率的测试值与理论计算值基本符合．     

新型柱孔式模式转换型纵-扭复合模态超声振动系统*

为了改善基于螺旋槽结构和斜槽结构的模式转换型纵-扭复合模态超声振动系统存在的结构复杂、扭转分量较小等问题,论文提出了基于新型柱孔式复合变幅杆的模式转换型纵-扭复合模态超声振动系统,并利用有限元法和数据分析对其进行了仿真分析,结果表明,引入新型柱孔式复合变幅杆的系统的输出端面的剪切应力、旋转角度得到了大幅提升,能够有效地提高纵、扭振动的转换效率。     

由瞬态响应的测量来估算超声马达的负载特性

为测量超声马达的一些特性,如最大力矩、负载特性(即力矩-速度特性)、转子和定子接触面上的摩擦系数等,本文提出一种由瞬态响应来估算的方法,由接通电源时马达转速阶跃响应的上开曲线可算出其负载特性,而由切断电源时的下降曲线得出接触面的摩擦系数。本方法测量时间快,故不受因温升导致的共振频率漂移等一些问题的困扰。对一混合换能器型旋转马达得到的负载特性与用拉重法所得结果符合很好。对一行波直线马达则考察了摩擦材料的杨氏模量和摩擦系数等参数对马达性能的影响。     

A cylindrical standing wave ultrasonic motor using bending vibration transducer

A cylindrical standing wave ultrasonic motor using bending vibration transducer was proposed in this paper. The proposed stator contains a cylinder and a bending vibration transducer. The two combining sites between the cylinder and the transducer locate at the adjacent wave loops of bending vibration of the transducer and have a distance that equal to the half wave length of bending standing wave excited in the cylinder. Thus, the bending mode of the cylinder can be excited by the bending vibration of the transducer. Two circular cone type rotors are pressed in contact to the end rims of the teeth, and the preload between the rotors and stator is accomplished by a spring and nut system. The working principle of the proposed motor was analyzed. The motion trajectories of teeth were deduced. The stator was designed and analyzed with FEM. A prototype motor was fabricated and measured. Typical output of the prototype is no-load speed of 165 rpm and maximum torque of 0.45 N m at an exciting voltage of 200 V_rms.     

Modeling and experimental analysis of the linear ultrasonic motor with in-plane bending and longitudinal mode

A novel linear ultrasonic motor based on in-plane longitudinal and bending mode vibration is presented in this paper. The stator of the motor is composed of a metal plate and eight piezoelectric ceramic patches. There are four long holes in the plate, designed for consideration of the longitudinal and bending mode coupling. The corresponding model is developed to optimize the mechanical and electrical coupling of the stator, which causes an ellipse motion at the contact tip of the stator when the composite vibrations with longitudinal and bending are excited. Its harmonic and transient responses are simulated and inspected. A prototype based on the model is fabricated and used to conduct experiments. Results show that the amplitude of the stator’s contact tips is significantly increased, which helps to amplify the driving force and speed of the motor. It is therefore feasible to implement effective linear movement using the developed prototype.     

A new standing-wave-type linear ultrasonic motor based on in-plane modes

This paper presents a new standing-wave-type linear ultrasonic motor using combination of the first longitudinal and the second bending modes. Two piezoelectric plates in combination with a metal thin plate are used to construct the stator. The superior point of the stator is its isosceles triangular structure part of the stator, which can amplify the displacement in horizontal direction of the stator in perpendicular direction when the stator is operated in the first longitudinal mode. The influence of the base angle θ of the triangular structure part on the amplitude of the driving foot has been analyzed by numerical analysis. Four prototype stators with different angles θ have been fabricated and the experimental investigation of these stators has validated the numerical simulation. The overall dimensions of the prototype stators are no more than 40 mm (length) × 20 mm (width) × 5 mm (thickness). Driven by an AC signal with the driving frequency of 53.3 kHz, the no-load speed and the maximal thrust of the prototype motor using the stator with base angle 20° were 98 mm/s and 3.2 N, respectively. The effective elliptical motion trajectory of the contact point of the stator can be achieved by the isosceles triangular structure part using only two PZTs, and thus it makes the motor low cost in fabrication, simple in structure and easy to realize miniaturization.     

A linear piezoelectric inchworm motor using ultrasonic clamping vibrator

This paper reports a kind of linear piezoelectric inchworm motor us-ing ultrasonic clamping vibrator with ring-shaped three-pile piececonstruction.The clamping vibrator and guide shaft of the motor constitutethe friction pair.The ratio of moving friction coefficient to static one is about1:10,when the clamping vibrator is in resonance.The driving peak voltage ofthe clamping vibrator is only 120V(V_(p-p)).The velocities of the motor are0-2 mm/min,the driving force is about 0.2 kgf,and the mechanic resolvingpower is less than 50nm.The motor's technique is simple.     

超声波马达的应用

超声马达具有诸多优良特性,它已经在很多领域得到了广泛的应用。本文介绍了超声马达的应用现状和发展前景。     

超声振子箝位压电直线微动马达研究

本文提出一种利用环形三叠片超声振子箝位的压电直线微动马达.这种马达的箝位振子与导轴形成摩擦付。振子共振时其动摩擦系数与静摩擦系数之比降为~0.1。箝位振子的激励电压仅为±80V(峰峰值)。马达速度为0—2mm/min;位移分辨率为50nm;驱动力约0.2kgf。这种马达还具有工艺简单的特点。     

Characteristics of ring type traveling wave ultrasonic motor in vacuum

The characteristics of ultrasonic motor strongly depend on the properties of stator/rotor contact interface which are affected by ambient environment. With the developed apparatus, load properties of two ring type traveling wave ultrasonic motors in atmosphere, low vacuum and high vacuum were studied, respectively. Wear of friction material, variations of vacuum degree and the temperature of motor during the experiment were also measured. The results show that load properties of motor A in vacuum were poorer than those in atmosphere, when load torque M_f was less than 0.55 N m. Compared to motor A, load properties of motor B were affected a little by environmental pressure. Wear of friction material in vacuum was more severe than wear in atmosphere. The temperature of motor in vacuum rose more quickly than it in atmosphere and had not reached equilibrium in 2 h experiment. However, the temperature of motor in atmosphere had reached equilibrium in about forth minutes. Furthermore, outgas was also observed during experiment under vacuum conditions.