考虑低载强化效应的变速器加速试验谱的编制

Compilation of the Accelerated Test Spectrum of Transmission based on Low Loading Strengthening Effect

变速器室内台架模拟试验是考核、评价和提升其性能的重要手段。以变速器为对象,提出了一种能简化变速器加速疲劳试验程序载荷谱的编制方法。利用无线遥测技术在垫江汽车试验场采集了汽车变速器的实际道路载荷谱,分挡位对实际载荷谱进行了预处理。以2挡载荷为例,应用雨流计数法得到载荷的频次分布矩阵,运用卡方检验发现载荷均值服从均值为91.77 N·m、标准差为163.27 N·m的正态分布,载荷变程服从形状参数为1.346、比例参数为305.489的双参数威布尔分布,并且均值和变程相互独立。利用二维概率分布函数,建立了8×8级二维载荷谱。应用变均值法,将二维载荷谱转化为8级一维载荷谱。依据半轴的损伤特性和低载强化特性,研究强化载荷之间的等强化准则,将强化载荷折算到最佳载荷级,减少了载荷加载频次,提高了试验效率。

The indoor simulation bench test of transmission is an important method of assessment,evaluation and promotion of its performance.Taking transmission as an example,a program load spectrum compiling method for transmission accelerated fatigue test is presented.The actual road load spectrum of automobile transmission is collected on Automobile Proving Ground in Dianjiang used wireless telemetry technology.The actual load spectrum is pretreated divided gear position,the second gear load spectrum is selected as an example.The frequency distribution matrix of load is obtained based on rainflow counting method,the distributions of mean and range are found to confirm with normal distribution and two- parameter Weibull distribution respectively.The mean of the normal distribution is 91.77 N·m,and the standard deviation is 163.27 N·m,the shape parameter of Weibull distribution is 1.346,and the scale parameter is 305.489,the distributions of load range and mean is independent.The two- dimensional load spectrum with 8×8 levels is established with joint probability distribution function.After two- dimensional load spectra is transformed into one- dimensional 8-level load spectra with variable mean method.Based on damage and low loading strengthening property of half shaft,the equivalent strengthening rule between strengthening loads is explored.By transferring the strengthening loads to the most effective level,the load loading frequency reduced,test efficiency is improved.