JB-T 51082-2000 拖拉机产品可靠性考核

T61JB/T51082－2000拖拉机产品可靠性考核（内部使用）2000-08-30发布2000-12-01实施国家机械工业局发布I前言1范围····················································································································································································································12引用标准·········································································································································································································13术语及定义····································································································································································································14故障分类及判断规则···············································································································································································25评定指标体系·······························································································································································································36评定方法·········································································································································································································47使用试验方法·······························································································································································································5附录A（提示的附录）试验报告格式················································································································································8附录B（提示的附录）拖拉机故障实例·········································································································································19JB/T51082－2000目次II前言本标准是对JB/T51082.1~51082.3—94的修订。修订时，对原标准作了编辑性修改，主要技术内容没有变化。本标准自实施之日起代替JB/T51082.1~51082.3—94。本标准的附录A、附录B都是提示的附录。本标准由全国拖拉机标准化技术委员会提出并归口。本标准负责起草单位：洛阳拖拉机研究所。本标准主要起草人：郭清臣、范建华、陈志强、杨希武、徐锦辉。JB/T51082－200011范围本标准规定了拖拉机产品可靠性考核的术语及定义、故障分类及判断规则、指标体系及评定办法和拖拉机可靠性使用试验方法等。本标准适用于批量生产的拖拉机的可靠性考核评定，试制样机的可靠性考核也可参照执行。2引用标准下列标准所包含的条文，通过在本标准中引用而构成为本标准的条文。本标准出版时，所示版本均为有效。所有标准都会被修订，使用本标准的各方应探讨使用下列标准昀新版本的可能性。GB/T3871—1993农业轮式和履带拖拉机试验方法GB/T6229—1995手扶拖拉机试验方法3术语及定义本标准采用下列术语及定义。3.1拖拉机工作时间拖拉机完成各种作业的运行时间。它包括拖拉机负荷作业时间、地头转弯时间和拖拉机空行折算时间（按5h空行时间折算1h工作时间），但不包括拖拉机磨合时间、性能试验时间和发动机空转时间。3.2故障修复工作时间指故障诊断、修理及调试的总时间，但不包括人为或自然因素所耽误的时间。3.3维护保养工作时间为完成使用说明书规定的维护保养所需要的工作时间。它包括班保养和各级保养所用的时间，但不包括人为或自然因素所耽误的时间。3.4故障（或失效）拖拉机或其零部件不能完成其规定功能或性能下降超过规定范围的一切现象。例如：零件损坏、磨损超限、焊缝开裂、油漆剥落、紧固件松动、标牌脱落及起动困难、功率下降、油耗上升、提升缓慢等超过规定值的现象。3.5本质故障由于拖拉机零、部件本身固有的缺陷而引起的故障称为本质故障。例如：由于强度、材质、加工和装配等原因引起的过度变形、断裂、过度磨损、腐蚀、老化、紧固件松动或失效、性能下降超限及“三漏”等。3.6从属故障国家机械工业局2000-08-30批准中华人民共和国机械行业标准拖拉机产品可靠性考核（内部使用）JB/T51082－2000代替JB/T51082.1~51082.3—942000-12-01实施JB/T51082－20002因本质故障导致产生的派生故障。例如：发动机由于连杆螺栓断裂导致一系列其它零件损坏，则连杆螺栓断裂属本质故障，由此引起的其它零件损坏均属从属故障。3.7误用故障用户不按使用说明书规定使用和操作而引起的故障称为误用故障。例如：驾驶员未按规定要求加油、加水，导致发动机抱缸、烧瓦；用户擅自改变某一结构或调整状态、超载使用等致使有关零、部件损坏。4故障分类及判断规则4.1根据拖拉机故障造成的危害程度及排除故障的难易性，将故障分为致命故障、严重故障、一般故障和轻度故障四类。其类别、名称、代号及定义见表1。严重故障和致命故障又统称停机故障。表1类别名称代号定义Ⅰ致命故障ZM危及或导致人身伤亡，引起主要总成报废或造成重大经济损失的故障Ⅱ严重故障YZ严重影响拖拉机正常使用，或者规定的重要性能下降超过规定范围，必须停机修理且修理费用较高，在较短的有效时间内无法排除的故障。即需要更换拖拉机部件或拆开机体更换内部零、部件的故障Ⅲ一般故障YB明显影响拖拉机正常使用，修理费用中等，在较短的有效时间内可以排除的故障。即需要更换或修理外部零件的故障Ⅳ轻度故障QD轻度影响拖拉机正常使用，暂时不会导致工作中断、修理费用低廉的故障。即在日常保养中能用随机工具轻易排除的故障4.2判断规则4.2.1可靠性考核应统计拖拉机发生的本质故障和与本质故障“同时发生”的从属故障（即应记入后果昀严重的故障）记入故障次数和发生时间。如本质故障和从属故障不同时发生，则按后果昀严重的故障记入类别，按本质故障发生时的时间记入故障时间。误用故障不计入故障次数，但应如实记入故障登记表。4.2.2判断拖拉机故障类别时，应以其昀终造成的后果来判定其故障类别，且只能判定为四类故障中的一类。4.2.3按使用说明书规定进行保养和按期更换的随机备件，不作故障处理，但应做好记录。4.2.4对“三漏”和紧固件松动等故障，在统计故障次数时，每一个密封结合面只统计一次，按昀严重的类别及程度记入次数及时间。4.2.5故障排除以后重复出现的同一故障，应分别统计其故障次数。4.2.6判断故障类别时，可参照附录B（提示的附录）。由于各种拖拉机的结构不同，同一名称故障所致后果及排除故障的难易程度会有较大差别，应按故障分类及定义，参照实例，根据具体情况来判定其类别。JB/T51082－200035评定指标体系拖拉机可靠性评定指标体系见表2。表2序号可靠性指标代号1首次故障前平均工作时间MTTFF2平均故障间隔时间MTBF3平均停机故障间隔时间DTMTBF4无故障性无故障性综合评分值Q5经济性工厂年平均保修费用率PWC5.1首次故障前平均工作时间MTTFF=+∑∑=−=rirnjjittr111…………………………………………（1）式中：MTTFF——拖拉机首次故障前平均工作时间，h；n——被试验或被调查拖拉机台数；r——被试验或被调查拖拉机在使用或试验时间内（包括磨合和性能试验期间）出现首次故障（轻度故障除外）的台数；ti——第i台拖拉机出现首次故障时的累计工作时间，h；tj——可靠性试验结束或用户调查时，未发生首次故障的第j台拖拉机累计工作时间，h；对试验拖拉机，为规定的定时截尾试验时间，h。若所有被试验的拖拉机均未出现故障（轻度故障除外），规定以MTTFF＞∑=njjt1表示。5.2平均故障间隔时间MTBF=∑=niitr1ca1…………………………………………（2）式中：MTBF——拖拉机的平均故障间隔时间，h；tci——第i台被试验拖拉机的定时截尾试验时间，h；对被调查拖拉机，为累计工作时间，h；ra——被试验或被调查拖拉机在使用或试验时期内（包括磨合和性能试验期间）出现的故障（轻度故障除外）总数。若所有被试验的拖拉机均未出现故障（轻度故障除外），规定以MTBF＞∑=niit1c表示。5.3平均停机故障间隔时间DTMTBF=∑=niitr1cd1………………………………………（3）式中：DTMTBF——拖拉机的平均停机故障间隔时间，h；rd——被试验或被调查拖拉机在使用或试验时期内（包括磨合和性能试验期间）出现的停机故障（即致命故障和严重故障）总数。JB/T51082－20004若所有被试验的拖拉机均未出现停机故障，规定以DTMTBF＞∑=niit1c表示。5.4无故障性综合评分值在规定的试验时间内，被试拖拉机中有1台出现了致命故障，则判定该型拖拉机的无故障性综合评分值为不及格，不再计算其Q值。对未出现致命故障的被试拖拉机，其无故障性综合评分值按式（4）计算：Q=100–()∑=c10griiiEKnTT………………………………………（4）式中：Q——被试拖拉机的无故障性综合评分值，分；Tg——拖拉机产品质量分等标准中规定的优等品MTBF目标值，h；n——第7章所规定的试验拖拉机台数；T0——第7章所规定的截尾试验时间，h；rc——在规定的截尾试验时间内，被试拖拉机出现的故障总数；Ki——第i个故障的危害度系数；各类故障的危害度系数规定为：Ⅱ类严重故障（YZ）：K=30.0Ⅲ类一般故障（YB）：K=8.0Ⅳ类轻度故障（QD）：K=1.0Ei——第i个故障的故障发生时间系数：Ei=()iTTT+00/2Ti——被试拖拉机出现第i个故障时，该拖拉机的累计故障时间，