基于超声波技术的径向滑动轴承润滑液工作状态研究

发布时间：2018-06-24 21:13

本文选题：超声波 + 径向滑动轴承　；参考：《长安大学》2015年博士论文

【摘要】：流体润滑油膜对于减小相对运动机件之间的摩擦和磨损具有重要的作用。油膜厚度过薄会导致机件表面的相互接触,进而产生较高摩擦和磨损,油膜厚度过大又会导致不必要的搅油能量损失。为了保证相对运动的机件能得到良好的润滑,同时又不损失过多的能量,需要确保润滑油膜的厚度。测量润滑油膜的厚度不仅有助于改进机件的设计,而且掌握润滑油膜的工作状态。润滑油膜的破裂会导致润滑失效,进而导致机件的毁坏,所以对润滑油膜厚度的测量是非常有必要的。超声波是一种非破坏性的、安全以及便携的技术。由于成本的降低和脉冲能力以及数字化技术的普及,超声波设备的使用越来越广泛。由于超声波的特性大部分都取决于传播介质,这使超声波技术非常适于用来检测润滑油膜的厚度。此技术通过检测由润滑油膜反射的一部分声波就可测量油膜厚度。但是由于在试验台搭建、超声波使用及其准确度验证等方面存在许多困难,此技术目前在油膜厚度检测方面的使用还有很多工作要做。本文利用高频超声波对径向滑动轴承内润滑液的油膜厚度和气穴效应进行了研究。并简化了测量系统,降低了测量成本,提高了超声波技术的便捷性,为实现径向滑动轴承油膜厚度的车载测量打下了坚实的基础,为后人的研究提供了理论依据,也为轴承的设计和特殊使用条件下润滑剂的选用提供了理论参考。最重要的是,掌握了润滑状态可以调节维护修理的周期,预防由于润滑失效导致的经济损失。本文首先根据所测目标是径向滑动轴承的瞬时油膜厚度而选择将超声波传感器安装在轴颈内部,与轴颈一起旋转;然后通过对径向滑动轴承模拟仪的形状和尺寸进行分析,选择了单独的压电元件作为超声波传感器进行超声波信号的发射和接收;在此基础上根据压电元件与油膜之间的距离选择了压电元件的频率;随后根据压电元件在工作时需要进行高速旋转的特性选择了合适的滑环解决与电源之间的电路连接问题;利用Labview软件编写程序对试验系统进行控制,并在其中运用弹簧模型利用反射率计算油膜厚度;设计了不同的试验台对弹簧模型中的参数进行测量;设计了特定的试验台考察温度对压电元件的影响;搭建试验台并在验证其可靠性的基础上对载荷、转速和温度的变化对径向滑动轴承的瞬时油膜厚度和气穴效应的影响进行了测量,并对可能导致润滑失效的工作条件进行了预测。本文的结果显示,超声波技术是一种十分可靠的油膜润滑状态测量技术,但是由于超声波波长限制,本文所开发的利用超声波技术和弹簧模型相结合测量油膜厚度的技术,只适用于微米级别的油膜厚度,且温度的升高会导致超声波传感器产生的超声脉冲的能量呈线性降低。径向滑动轴承的载荷变大、温度升高、转速降低都会导致最小油膜厚度的减小、轴颈与轴瓦上加载点位置之间的距离越来越近以及气穴效应的增大。
[Abstract]:Fluid lubricating oil film plays an important role in reducing friction and wear between the relatively moving parts. Too thin film thickness will lead to contact on the surface of the machine, resulting in higher friction and wear. Too much oil film thickness will lead to unnecessary oil stirring energy loss. In order to ensure the relative motion of the machine can be well run. It needs to ensure the thickness of the lubricating oil film without losing too much energy at the same time. Measuring the thickness of the lubricating film not only helps to improve the design of the machine parts, but also grasps the working state of the lubricating film. The rupture of the lubricating oil film will lead to the failure of the lubrication and cause the destruction of the machine parts, so it is very necessary to measure the thickness of the lubricating oil film. Yes. Ultrasonic is a non destructive, safe and portable technology. The use of ultrasonic equipment is more and more widely used because of cost reduction, pulse ability and the popularization of digital technology. The characteristics of ultrasonic wave are mostly dependent on Yu Chuanbo medium, which makes ultrasonic technology very suitable for detecting the thickness of lubricating oil film. This technique can measure the thickness of the oil film by detecting a part of the acoustic wave reflected from the lubricating oil film. But because there are many difficulties in the use of ultrasonic and its accuracy verification in the test bench, there are many work to do in the field of oil film thickness detection. The oil film thickness and cavitation effect of the inner lubricating fluid are studied, and the measurement system is simplified, the measurement cost is reduced, the convenience of the ultrasonic technology is improved, the solid foundation for the vehicle measurement of the oil film thickness of the radial journal bearing is laid down, the theoretical basis is provided for the research of the later people, and the design and special of the bearings are also provided. A theoretical reference is provided for the selection of lubricants under special conditions. The most important thing is that the lubrication state can be controlled to maintain the repair period and prevent the economic loss due to lubrication failure. Firstly, the ultrasonic sensor is chosen to be installed in the neck of the shaft according to the instantaneous oil film thickness of the radial sliding bearing. Through the analysis of the shape and size of the radial journal bearing simulator, a single piezoelectric element is selected as the ultrasonic sensor to transmit and receive the ultrasonic signal. On this basis, the frequency of the piezoelectric element is selected according to the distance between the piezoelectric element and the oil film; then the piezoelectric element is based on the piezoelectric element. In the work, the characteristic of high speed rotation is needed to choose the suitable slip ring to solve the circuit connection between the power and the power supply. The test system is controlled by Labview software program, and the spring model is used to calculate the oil film thickness by using the reflectivity, and the parameters of the spring model are designed by different test rig. The influence of the temperature on the piezoelectric element is designed and the test bench is built to measure the influence of the load, speed and temperature on the instantaneous oil film thickness and cavitation effect of the radial sliding bearing on the basis of its reliability, and the working conditions that can lead to the failure of the lubrication are predicted. The results of this paper show that ultrasonic technology is a very reliable technique for measuring the state of oil film lubrication. However, because of the limitation of ultrasonic wave length, the technique used in this paper to measure the thickness of oil film by combining the ultrasonic technology with the spring model is only suitable for the thickness of the oil film in the micron level, and the increase of temperature will lead to ultrasonic sensing. The energy of the ultrasonic pulse produced by the device decreases linearly. The load of the radial journal bearing becomes larger, the temperature increases and the speed decreases, which will result in the decrease of the minimum oil film thickness, the distance between the position of the load point on the shaft neck and the axle bush, and the increase of the cavitation effect.
【学位授予单位】：长安大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TH133.31;TB553

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