高速重载滑动轴承的润滑特性研究

发布时间：2018-12-16 02:31

【摘要】：随着工程机械向着高速、重载方向的飞速发展,在行星传动机构中,为了获得更高的传动性能和功率密度,改善低速传动状况下的滚动轴承已远远不能满足使用寿命的现状,因此本文采用滑动轴承作为行星轮支承来研制高速行星传动机构。通常人们研究滑动轴承时都忽略了表面粗糙度对润滑特性的影响,而实际加工生产的轴承表面不可能完全光滑,且加工工艺不同,粗糙值的大小与方向也各不相同,因此对轴承的润滑特性也会产生不同的影响,特别是在高速、重载条件时,理想状态下分析结果与实际存在着很大差异,因此研究表面粗糙度对高速、重载下的滑动轴承润滑特性的影响具有十分重要的意义。本文首先介绍了滑动轴承的运动状态以及油膜产生动压润滑的原理,根据流体动压润滑理论建立了滑动轴承的力学模型,引入了雷诺方程(Reynolds)的假设条件,推导出雷诺方程且进行了简化,并根据工程实际确定了雷诺方程的边界条件；其次,利用MatLab数值分析软件使用有限差分法对滑动轴承在理想状态下的各项润滑性能参数进行求解分析,验证了计算方法的正确性,通过分析相对间隙、温度及负荷率对润滑性能的影响,得出了滑动轴承适合重载工况的结论；研究了高速、重载工况下,计入表面粗糙度后对各项润滑特性产生的影响,并与理想状态下的特性进行了对比分析,结果表明,在转速为12000rad/min、ε=0.8的大偏心率(即重载)工况下,油膜最大压力比理想状态下大1倍,特别是轴瓦表面粗糙度值对滑动轴承各项性能参数的影响比较大。为了更好地研究滑动轴承的润滑特性,利用EMD算法将故障信号分解成具有一定平稳性的固有模态函数分量,并对每一个分量建立了基于故障信号的AR模型,以此模型的自回归参数和残差的方差作为特征向量建立SVM回归分类模型,进而判断了轴承的工作状态和故障类型。实验数据证明,滑动轴承工作状态和故障类型符合滑动轴承的各种性能参数的变化规律,为进一步研究滑动轴承的润滑特性提供了科学有力的实验依据,使本课题研究更加具有实际应用价值。
[Abstract]:With the rapid development of construction machinery in the direction of high speed and heavy load, in order to obtain higher transmission performance and power density, the rolling bearing under the condition of low speed transmission is far from being able to meet the service life in the planetary transmission mechanism. Therefore, a high-speed planetary transmission mechanism is developed by using sliding bearings as planetary gear supports. In general, the influence of surface roughness on lubrication characteristics is neglected when people study sliding bearings. However, the surface of bearings produced in actual processing cannot be completely smooth, and the rough values are different in size and direction with different processing technology. Therefore, there are different influences on the lubrication characteristics of bearings, especially under the conditions of high speed and heavy load, the results of analysis in ideal state are quite different from those in practice, so the surface roughness is studied for high speed. The influence of lubricating characteristics of sliding bearing under heavy load is very important. In this paper, the motion state of sliding bearing and the principle of hydrodynamic lubrication produced by oil film are introduced. According to the hydrodynamic lubrication theory, the mechanical model of sliding bearing is established, and the assumption condition of Reynolds equation (Reynolds) is introduced. The Reynolds equation is deduced and simplified, and the boundary conditions of the Reynolds equation are determined according to the engineering practice. Secondly, the MatLab numerical analysis software is used to solve and analyze the lubrication performance parameters of sliding bearings in ideal condition by using finite difference method, which verifies the correctness of the calculation method. The influence of temperature and load rate on lubricating performance and the conclusion that the sliding bearing is suitable for heavy load condition is obtained. The effects of high speed and heavy load on the lubricating properties under the condition of high speed and heavy load are studied and compared with the ideal conditions. The results show that the rotational speed is 12000rad/ min. Under the condition of large eccentricity (i.e. heavy load) of 蔚 = 0.8, the maximum pressure of oil film is twice greater than that under ideal condition, especially the influence of bearing surface roughness value on the performance parameters of sliding bearing. In order to better study the lubrication characteristics of sliding bearings, the fault signals are decomposed into intrinsic modal function components with certain stationarity by using EMD algorithm, and the AR model based on fault signals is established for each component. Based on the autoregressive parameters of the model and the variance of the residuals as the eigenvector, the SVM regression classification model is established, and the working state and fault type of the bearing are judged. The experimental data show that the working state and fault type of sliding bearing conform to the variation rule of various performance parameters of sliding bearing, which provides a scientific and powerful experimental basis for further study of lubricating characteristics of sliding bearing. Make this research more practical application value.
【学位授予单位】：河北工程大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH117.2

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