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针对数控机床的运行可靠性规律进行了研究。根据采集的国产机床运行数据,对其无故障运行间隔时间进行统计分析,确定其分布类型服从威布尔分布。利用威布尔分布的参数评估方法,确定出三参数威布尔分布的各个特征量,并与两参数威布尔分布相比较。运用威布尔分布模型及可靠性评定方法确定出数控机床的平均无故障时间和使用可靠性规律。 相似文献
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基于相关系数法的数控机床评价模型 总被引:1,自引:0,他引:1
针对数控机床故障间隔时间分布模型的参数精度不高且不方便计算的问题,基于相关系数法利用Matlab编程来估计数控机床威布尔分布的三个参数,使其既符合精度要求,又易于实现。 相似文献
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三参数威布尔分布具有很多优点,能充分地描述失效机理,非常适合于作为前轮转弯减摆助力器可靠性数据分析模型。基于使用阶段的随机截尾型可靠性数据,首先提出了采用最小二乘法和相关系数法相结合来估计三参数威布尔分布的参数,在此基础上,提出了基于三参数威布尔分布的前轮转弯减摆助力器可靠性数据分析的方法,最后进行了仿真试验研究。仿真试验结果表明,前轮转弯减摆助力器的三参数威布尔分布模型比两参数威布尔分布模型更为精确。研究成果为航空产品在使用阶段提供了一种更为精确的可靠性分析方法。 相似文献
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将现场收集到的TK6920型重型落地镗铣床的故障间隔时间进行整理,绘制出概率密度曲线和累积概率曲线,据此初步判断故障间隔时间服从二参数威布尔分布,并对分布模型进行了拟合检验,最后建立了故障间隔时间的二参数威布尔分布模型,同时给出了平均故障时间MTBF的点估计值和观测值。由于二参数威布尔分布模型的形状参数m1,可以判断该型重型机床的故障以早期故障为主,应着手制定早期故障试验规范来降低故障率。 相似文献
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《机械工程学报(英文版)》2018,(6)
The current research of reliability allocation of CNC lathes always treat CNC lathes as independent series systems. However, CNC lathes are complex systems in the actual situation. Failure correlation is rarely considered when reliabil?ity allocation is conducted. In this paper, drawbacks of reliability model based on failure independence assumption are illustrated, after which, reliability model of CNC lathes considering failure correlation of subsystems is established based on Copula theory, which is an improvement of traditional reliability model of series systems. As the failure time of CNC lathes often obeys Weibull or exponential distribution, Gumbel Copula is selected to build correlation model. After that, a reliability allocation method considering failure correlation is analyzed based on the model established before. Reliability goal is set first and then failure rates are allocated to subsystems according to the allocation vector through solving the correlation model. Reliability allocation is conducted for t = 1. A real case of a CNC lathe and a numerical case are presented together to illustrate the advantages of the reliability model established consider?ing failure correlation and the corresponding allocation method. It shows that the model accords to facts and real working condition more, and failure rates allocated to all the subsystems are increased to some extent. This research proposes a reliability allocation method which takes failure correlation among subsystems of CNC lathes into consid?eration, and costs for design and manufacture could be decreased. 相似文献
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数控机床故障诊断与维护是数控机床使用过程中重要组成部分,也是目前制约数控机床发挥作用的重要因素。在阐述数控机床故障分布规律的基础上,分析了数控机床常见的故障模式。剖析了系统故障诊断内容及方法,并提出了提出了相应的维护措施,对于开展数控机床故障诊断与维护的研究具有重要意义。 相似文献
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谢林 《机电产品开发与创新》2008,21(1):177-178
成形面是车削加工中经常遇到的。在普通车床上加工一般要使用成形刀或靠操作者用双手同时操作完成,在数控车床上则通过程序控制团孤插补指令进行加工^[1]。二者相比,数控车床具有很大的优势,但必须掌握一定的技巧,才能顺利地加工出所需要的成形面。本文从四个方面并利用加工实例对在数控车床上加工成形面的技巧进行了探讨,具有较强的实用性。 相似文献
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在对14台数控车床进行长达两年的现场故障信息跟踪收集的基础上,建立了可靠性信息数据库;重点研究了数控车床故障间隔时间的分布模型,并给出了可靠性特征量函数。 相似文献
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在对数控机床控制原理进行分析与研究的基础上,通过具体案例详细介绍了PLC技术在数控机床控制中的应用,举例说明了通用型卧式数控车床的PLC程序编写方法,并结合典型实例,对利用PLC实现故障诊断进行了分析. 相似文献
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介绍数控车床主轴自动换档的工作原理、相关系统参数设置及控制流程,对主轴自动换档过程中各种形式的故障进行了归纳、总结,并给出常见故障的分析案例。 相似文献
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Reliability allocation of computerized numerical controlled(CNC)lathes is very important in industry.Traditional allocation methods only focus on high-failure rate components rather than moderate failure rate components,which is not applicable in some conditions.Aiming at solving the problem of CNC lathes reliability allocating,a comprehensive reliability allocation method based on cubic transformed functions of failure modes and effects analysis(FMEA)is presented.Firstly,conventional reliability allocation methods are introduced.Then the limitations of direct combination of comprehensive allocation method with the exponential transformed FMEA method are investigated.Subsequently,a cubic transformed function is established in order to overcome these limitations.Properties of the new transformed functions are discussed by considering the failure severity and the failure occurrence.Designers can choose appropriate transform amplitudes according to their requirements.Finally,a CNC lathe and a spindle system are used as an example to verify the new allocation method.Seven criteria are considered to compare the results of the new method with traditional methods.The allocation results indicate that the new method is more flexible than traditional methods.By employing the new cubic transformed function,the method covers a wider range of problems in CNC reliability allocation without losing the advantages of traditional methods. 相似文献
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现在的数控设备都带有专用的通讯接口,都可实现机床与计算机的联接通讯。广西机械高级技工学校的10台数控车床通过通讯网络改造以及改造实训教室与CAD/CAM仿真教室的电脑网络联接,实现了在CAD/CAM仿真教室应用CAD/CAM软件完成加工程序的自动生成,并通过仿真软件的检验,把正确的程序传到机床上,实现自动编程的加工。 相似文献