【作者】 黄超群；

【导师】 许良军；

【作者基本信息】 北京邮电大学 ， 检测技术与自动化装置， 2010， 硕士

【摘要】 电接触广泛存在于电子和电力系统中,元件之间、电路之间、设备之间乃至元件内部之间都需要可靠的电子连接。研究表明：尘土污染是造成电子元件电接触故障的主要原因之一。因此,研究尘土对电接触性能的影响,对提高电子、电气系统的可靠性具有十分重要的意义。本文中,将尘土对电器电接触的影响细分为尘土进入电器和尘土在电器内部影响电接触性能两个过程分别研究。对尘土进入电器的过程,主要考虑电场因素对尘土进入电器的影响作用。以手机为例的3.7V低电压电器为研究对象,通过ANSYS大型有限元软件建模分析得到电场强度,计算带电尘土颗粒受到的电场力。通过尘土受力分析,得到尘土颗粒所受的电场力与其所受的风力、重力相比几乎可以忽略不计的重要结论,并设计相应的实验进行验证和分析,在此基础上扩展研究220V以上电压的电器,给出了一个电器电场对尘土吸引力的极限条件。研究尘土进入电器内部后使电接触失效,可根据可靠性理论设计尘土沉积实验,得到尘土沉积密度的时间曲线。以洁净样片200次电阻测试的最大值作为压着尘土颗粒的判据,得到压着概率达到90%以上的危险尘土密度临界值为300个／mm2。对压着概率和尘土密度进行曲线拟合,得到拟合效果较好的几种函数形式,分析认为四次多项式和幂函数拟合是最符合要求的。根据常用场合中触头间的接触电阻低且稳定的正常接触电阻值范围,提出100mΩ接触电阻值作为一定范围内的接触失效指标,并用二次正态逼近拟合其与尘土密度之间的关系。最后,提出两种拟合曲线通用性分析的方法,并给出通用性的适用范围。更多还原

【Abstract】 There are numerous electric contacts in electronics, electric-power and automatic control system. Their capability affects the reliability of electric and electronic devices directly. Lots of studies indicate that dust is one of the factors causing electric contact failures. Therefore the research of electric contact in dusty environment will improve the reliability of electric and electronic system. In this paper, the effects of dust particles on electric contact are detailed into two parts, one is the dust ingression, and the other is electric contact failures after dust deposition.The research of dust ingression mainly focuses on the electric field factors. Two-dimensional electro-magnetic models of finite element method were established using ANSYS software, simulated for mobile phones (3.7V). The electric field force after calculated is much smaller compared with the air flowing force and the gravity. This analysis proved the important results that the electric characteristic of electronic devices effects on dust deposition could be ignored, then relevant experiment are designed for analysis and verification. Extend to electronic Apparatus above 220V, the extreme ranges are given when electric filed are under the consideration.Dust deposition experiment is designed based on reliability theory, in order to research the process of electric contact failures. The criterion is given from the maximum of 200 dust tests on clean materials, and inserted probability of the dust is available.300/mm2 is gotten as the hazardous dust density that the inserted probability reaches above 90%. Furthermore, the curve fitting analysis of the inserted probability and dust density is discussed. The fitting result show that some functions are better forms, but the 4th polynomial and Power function is the best through analysis. Then contact resistance of 100mΩis given as the failure criterion in some field, and its probability fitting with the relevant dust density is given as the best form of the 2nd Gaussian function. Finally, two methods of curve generality analysis are discussed and its working area is given.更多还原