【作者】 王辉；

【导师】 程天良； 蒋文科；

【作者基本信息】 河北农业大学 ， 农业机械化工程， 2004， 硕士

【摘要】 在液体中发射足够大的超声波能量，液体会产生“空化效应”。“空化效应”是将超声频的振动加到清洗液中，液体内部会产生拉伸和压缩现象，液体拉伸时会产生气泡，液体压缩时气泡会被压碎破裂。超声波清洗的原理就是在清洗液中产生“空化效应”，气泡的产生与破裂产生强大的机械冲击力，用以清除物体表面的杂质、污垢和油腻。超声波清洗机的清洗速度快，可提高生产效率：操作实现自动化，不须人手接触清洗液，安全可靠，且节省人力；微小的气泡可以到达特殊造型的零部件深处，对深孔、细逢和工件隐蔽处亦可清洗干净，所以超声清洗应用更为广泛；清洗效果好，清洁度高且全部工件清洁度一致，实验显示，利用超声波清洗技术，可得到比风吹、浸润、蒸汽和刷子清洗更好的清洗效果。使用超声波达到清洗目的，需要有容器与清洗液、超声波换能器、超声波电源。超声波换能器是产生超声场的部件，超声波电源用以驱动超声波换能器，向其提供能量，使之产生超声场。通常的超声波清洗机是在匹配电路上加占空比为50％的交流方波信号。本设计采用频率自动跟踪的方式来使超声波换能器处于谐振，满足超声波电源与超声波换能器工作在最佳状态，使得整机达到最佳工作效率。功率检测电路调节脉冲电压的脉宽来改变超声波发生器的输出功率，以实现功率恒定。压控振荡器选用货源充足、价格低廉的TL494，可满足本设计要求。D类功率放大器就是开关功率放大器，选用高耐压的VMOS管，组成全桥电路，VMOS管的驱动采用变压器隔离倒相。由于超声波换能器的特性，超声波清洗机中的匹配电路包含两个：一个是功率匹配，一个是调谐匹配。前者是为了使超声波电源的输出内阻与负载阻抗相一致，采用变压器匹配方法。后者是使换能器呈现纯阻性，采用串联电感的方法。 本文对系统的总体设计方案、硬件和软件设计、单元电路及主要单元电路实验进行了详细地介绍。更多还原

【Abstract】 "Cavitation effect" will happen if great ample ultrasonic energy is transmited in liquit. When plussing the ultrasonic frequency vibration up washing liquit,stretching and compression phenomenon will appear in liquid inside. The stretched Iiquit will create air bubbles,while the pressed Iiquit will crush the bubbles.The principle of ultrasonic washing is to come into being "cavitation effect". The powerful creating and crushing force can purge impurities,dirtetc.With ultrasonic washer,the cleaning speed is faster and the efficiency can be improved.The automation is achieved in the operation and workers have not to touch washing fluid,so it is safe and reliable and save the labour power.The little air bubbles may reach the interstices,apertures and shelter of parts to clean,so it is more wide-applicated.lt is good to wash effect.Tests display that ultrasonic washing machines may obtain better effect,comparing with the ways of puffing,infiltrating,steaming and brushing.Ultrasonic transducer is the part of producing ultrasound and supersonic power offers energy to the transducers.The ultrasonic cleaners is to plus square wave signal of 50% on the matching circuit. This design adopts the frequency tracing to make the whole system work in the resonance,causing that the whole set attains optimum work efficiency.By means of regulating the width of fluctuation voltage,the power inspection circle can control the output power ,so that the system can make the output power changeless.As being opulent and cheap,TL494 is choose as VCO.High Vceo VMOS is choose in the D generic power amplifier circle. The drive of VMOS adopts a paraphase transformer.Since ultrasonic transducers’ property,the matching circuit embodys two parts:One is power matching ,the other is attune matching.The former is for the sake of making export impedance of power match the load.This Adopts the transformer matching means.The latter is to make the transducer present only the quality of resistance.To get this,a inductor in series means is Adopted.This thesis introduces the design project,design of hardware and software,unit circles and experimentations of main unit circles in detail.更多还原