【作者】 张永奎；

【导师】 李国平；

【作者基本信息】 济南大学 ， 机械电子工程， 2011， 硕士

【摘要】 轴承是机械工业中重要的基础零部件,而钢球作为球轴承的滚动体,它的质量优劣对轴承的运动精度、寿命、性能等起决定性作用,其中钢球表面缺陷对钢球质量的影响尤为明显,加工后的部分钢球表面会存在麻点,斑点,烧伤,擦痕,划条,凹坑等缺陷,这些表面缺陷使球轴承在旋转运动时产生大的噪声和振动,是制约球轴承质量提高的关键因素。国产钢球的表面质量与国外同级别的相比仍然存在较大的差距,造成这种差距的原因之一就是钢球检测技术的落后。开发一种价格适中,高速高效的钢球表面质量检测设备迫在眉睫。本文提出的基于光纤传感技术的钢球表面缺陷检测研究是以山东省优秀中青年科学家科研奖励基金项目(钢球表面缺陷的多光纤检测机理研究)、山东省高等学校科技计划项目(基于光纤传感器的钢球表面质量检测机理研究)、济南大学校博士基金项目(轴承钢球质量检测与分选控制系统研究)、企业委托项目(轴承钢球质量的检测与分选控制系统开发)为依托,以钢球表面缺陷为研究对象,以反射式强度型光纤传感器工作特性为基础,着重研究钢球表面缺陷的自动检测技术,目的就是为了解决我国在钢球表面质量检测方面自动化程度低,效率低的“瓶颈”,开发出具有自己独立知识产权的钢球外观检测仪。分析了钢球表面缺陷参数和特征,用表面缺陷参数将表面缺陷量化,从表面缺陷深度、表面缺陷高度和表面缺陷反射率三个参数对钢球表面缺陷进行新的分类,将钢球表面缺陷的检测转换为位移量和反射率的检测。基于均匀分布模型和准高斯分布模型分别建立了单发单收和单发多收光纤传感器数学模型,通过仿真分析光纤参数对光纤传感器的影响,确立了钢球表面缺陷检测光纤传感器参数(纤芯/包层直径,数值孔径等)。探索出粗糙表面散射理论和双光束补偿测量法在钢球表面缺陷参数分离提取中的可行性,通过同轴型光纤传感器实现了位移量和反射率两类参数的分离提取。建立了钢球经纬(子午线)展开机构工作轨迹的数学模型并用Simulink进行了仿真,分析了光纤探头在钢球上的扫描轨迹以及展开轮在实现经纬展开方式的工作原理,为钢球展开机构的制作奠定了理论基础。基于调制技术和锁相放大技术,分析并设计了钢球表面缺陷信号处理系统,包括激光激励驱动电路、窄带滤波电路、相敏检波电路、移相电路、除法运算电路、信号采集等,通过锁相放大技术可以大大提高信噪比,消除掉由于展开机构的振动等因素带来的噪声,实现了信号的采集,处理与显示。构建了钢球表面缺陷光纤检测总体系统,通过实验可以看出:用反射率参数来检测钢球表面缺陷,展开机构振动对其影响很小,不会出现将好球检测为坏球的情况,但会出现漏检的情况;用位移参数来检测钢球表面缺陷,展开机构振动对其影响非常大,甚至可能将信号淹没,如果展开机构做得足够精密,可以很好检测钢球表面缺陷,用两种参数同时进行检测可以减小漏检率。通过分析与设计,初步建立起一套基于光纤传感技术的钢球表面缺陷检测体系,为以后钢球表面缺陷检测机的研制奠定基础。更多还原

【Abstract】 Surface quality of bearing ball is one of important factors to improve service performance,which plays a decisive role in the accuracy, campaign performance and the service life of the bearings. Defects of steel balls after processing can be classified as craze, spot, pitting, scratch, scoring and dent, which are a general taxonomy. It is difficult to detect bearing ball surface defects with high precision and low cost by conventional methods. In domestic factories for bearing or steel ball, the manual visual method is mostly adopted to inspect surface quality of steel ball, false inspecting rate of which is usually high because of many labile factors such as worker’s technical ability, emotion, tiredness, etc. That is to say, one important reason of backward development of bearing industry lies in the lagging inspection technique. The automatic and low cost inspection instrument is urgently required.In this paper one new classification method based on optical fiber sensing technology was put forward from the longitudinal section angle to inspection of steel ball surface defects. The work is supported by Shandong Scientific Research Foundation for Excellent Young Scientists (BS2010ZZ001), Shandong Department of Education Foundation (J10LD22), Doctor Foundation of University of Jinan (XBS0854) and a project of enterprise entrustment.In order to quantify and identify defects automatically, we divide the defects into three categories in accordance with surface imperfection parameters such as surface imperfection depth, surface imperfection height, and surface imperfection reflectivity,so that: the problem for detecting defects is changed into detecting the displacement information and the change of reflected or scattered light, which reflects the change of reflectivityof defects.Inspection mechanism of fiber sensors with single transmitter and single receiver as well as single transmitter and multiple receivers were analyzed based on uniform distribution model and semi-Gaussian distribution model, the mathematical models of the two fiber sensors were established and numerical simulations were realized with Matlab software. Influence of optical fiber parameters on light intensity modulation characteristic regulation was studied,through which the optical fiber sensor parameters(core / cladding diameter, numerical aperture, etc.) for steel ball surface defect detection were established. Beckmann scattering theory and the assumption of Suganuma Shimamoto double-beam compensation were analysised to extract defect parameters .Light intensity modulation characteristic experiments were done with specimens of different reflectivity and processing methods. The results show optical fiber sensing technique is an effective method to separate different surface of steel ball with extracting of two parameters displacement and surface reflectivity.Trajectory path mechanism of steel ball in deployment system was established, the simulations of which were realized with Simulink.the principle and form of unfolded-wheel were analyzed,with which the steel ball was unfold completely,and also a simple deployment system was designed for experiment.Based on modulation and lock-based amplification technology, the signal processing systems was analyzed and designed, including laser excitation driver circuit, narrow-band filter circuit, phase sensitive detection circuit, division operation circuit,A/D conversion and the signal acquisition and processing, through the lock phase amplification technique, the signal to noise ratio was greatly improved, and also signal acquisition and data analysis and display was realized.The system for steel ball defects inspection based on optical fiber sensing technique were constructed, the experimental results shows that: when the steel ball was inspected using imperfection reflectivity, light intensity is not sensitive to the vibration of deployment system, the case that the good steel ball was identified as steel ball with defects did not happen. However, the miss-detect situation appeared. when the steel ball was inspected using surface imperfection depth and surface imperfection height, light intensity is sensitive to the vibration of deployment system, some surface defects signal are too weak to be distinguished from the background noise. If the deployment system is precise enough, the steel ball can be identified very well.Through analysis and design, the surface defect detection system based on optical fiber sensing technology was set up ,which lay the theoretical basis for automatic checking and sorting machine of steel ball.更多还原