發(fā)布時(shí)間：2018-12-12 23:22

【摘要】：重型數(shù)控機(jī)床肩負(fù)著眾多關(guān)系國(guó)民經(jīng)濟(jì)與國(guó)防安全的行業(yè)產(chǎn)品及關(guān)鍵零部件的加工制造,其質(zhì)量、性能和技術(shù)水平是衡量一個(gè)國(guó)家工業(yè)化水平和綜合經(jīng)濟(jì)實(shí)力的重要標(biāo)志。國(guó)產(chǎn)重型數(shù)控機(jī)床經(jīng)過多年的發(fā)展已取得一定成就,但由于國(guó)產(chǎn)重型數(shù)控機(jī)床科技創(chuàng)新不足,基礎(chǔ)實(shí)驗(yàn)條件缺乏,高級(jí)人才匱乏,尖端核心技術(shù)尚未突破,其在使用過程中不斷暴露出早期故障頻發(fā)、質(zhì)量穩(wěn)定性差、維護(hù)成本高等問題,這些問題給重型數(shù)控機(jī)床用戶帶來系列困難和挑戰(zhàn),并直接導(dǎo)致我國(guó)國(guó)產(chǎn)重型數(shù)控機(jī)床可靠性差、產(chǎn)品附加值低、產(chǎn)業(yè)化能力弱、國(guó)際競(jìng)爭(zhēng)力不強(qiáng)等惡劣局面�，F(xiàn)有數(shù)控機(jī)床可靠性技術(shù)體系多是針對(duì)中小型數(shù)控機(jī)床構(gòu)建,針對(duì)重型數(shù)控機(jī)床可靠性技術(shù)的研究尚未深入開展。由于重型數(shù)控機(jī)床在結(jié)構(gòu)形式、加工任務(wù)等方面與中小型數(shù)控機(jī)床大有不同,現(xiàn)有可靠性技術(shù)不能直接應(yīng)用。因此,亟需針對(duì)重型數(shù)控機(jī)床結(jié)構(gòu)功能特點(diǎn),開展重型數(shù)控機(jī)床可靠性技術(shù)體系研究�？煽啃越Ｅc分析是重型數(shù)控機(jī)床可靠性技術(shù)體系的關(guān)鍵組成部分。重型數(shù)控機(jī)床可靠性建模與分析是在綜合研究機(jī)床可靠性影響因素和可靠性數(shù)據(jù)特征的條件下,以典型系統(tǒng)可靠性模型為基礎(chǔ),結(jié)合重型數(shù)控機(jī)床結(jié)構(gòu)功能特點(diǎn),建立數(shù)學(xué)模型來對(duì)其可靠性進(jìn)行分析和評(píng)定的過程。相對(duì)于普通數(shù)控機(jī)床,重型數(shù)控機(jī)床可靠性建模與分析具有系統(tǒng)結(jié)構(gòu)復(fù)雜、整機(jī)及關(guān)鍵零部件樣本少、試驗(yàn)數(shù)據(jù)不足、信息不全、可靠性數(shù)據(jù)類型多樣、故障機(jī)理復(fù)雜且故障相關(guān)等難點(diǎn)。針對(duì)以上重型數(shù)控機(jī)床可靠性研究難點(diǎn),本文主要開展以下研究工作:(1)以重型數(shù)控機(jī)床主軸為研究對(duì)象,分析了影響重型數(shù)控機(jī)床主軸可靠性的各種不確定性因素及現(xiàn)有不確定性量化方法的局限性,構(gòu)建了基于不精確概率理論的混合不確定性統(tǒng)一量化框架。在混合不確定性統(tǒng)一量化框架下,基于應(yīng)力-強(qiáng)度干涉理論,提出了針對(duì)機(jī)床零部件的不精確結(jié)構(gòu)可靠性建模一般方法。以某重型數(shù)控落地銑鏜床銑軸為例,對(duì)銑軸的多個(gè)失效模式進(jìn)行了不精確結(jié)構(gòu)可靠性分析、建模與計(jì)算。(2)在混合不確定性統(tǒng)一量化框架下,針對(duì)機(jī)床零部件,提出了考慮多失效模式相關(guān)性的結(jié)構(gòu)可靠性建模與分析方法。失效模式多樣且失效相關(guān)是機(jī)床零部件失效的普遍特征,現(xiàn)有文獻(xiàn)對(duì)失效相關(guān)性的研究基于大量故障統(tǒng)計(jì)數(shù)據(jù),未考慮數(shù)據(jù)不足情況,這與重型數(shù)控機(jī)床實(shí)際數(shù)據(jù)特征不符。針對(duì)該問題,本文引入表征相關(guān)性的Copula函數(shù)于不精確結(jié)構(gòu)可靠性模型中,提出了考慮多失效模式相關(guān)的不精確結(jié)構(gòu)可靠性改進(jìn)模型,并將該改進(jìn)模型應(yīng)用到銑軸可靠性建模與分析中,實(shí)現(xiàn)了銑軸多失效模式相關(guān)性分析與計(jì)算,通過與失效獨(dú)立條件下的計(jì)算結(jié)果進(jìn)行對(duì)比,驗(yàn)證了工程實(shí)際中考慮失效相關(guān)的必要性。(3)重型數(shù)控機(jī)床整機(jī)及其子系統(tǒng)的可靠性仍受到混合不確定性因素影響,且各子系統(tǒng)失效相互關(guān)聯(lián),本文綜合考慮以上兩個(gè)因素,以零部件混合不確定性統(tǒng)一量化、零部件不精確結(jié)構(gòu)可靠性建模、零部件失效相關(guān)性分析為基礎(chǔ),提出了同時(shí)考慮混合不確定性和失效相關(guān)性的系統(tǒng)可靠性建模與分析方法,并分別建立了典型系統(tǒng)不精確可靠性模型、基于故障樹分析的系統(tǒng)不精確可靠性模型;重型數(shù)控機(jī)床主軸系統(tǒng)組成零部件眾多,對(duì)各個(gè)零部件均進(jìn)行故障相關(guān)性分析,工作量巨大,本文借助于DEMATEL方法,分析了主軸系統(tǒng)各個(gè)零部件的故障重要程度、零部件故障關(guān)聯(lián)程度,以銑軸組件為研究重點(diǎn),完成了銑軸組件的不精確可靠性建模與分析。(4)重型數(shù)控機(jī)床在設(shè)計(jì)研制階段經(jīng)過“設(shè)計(jì)-試驗(yàn)-改進(jìn)-再設(shè)計(jì)-再試驗(yàn)”、“研制-測(cè)試-改進(jìn)-再研制-再測(cè)試”的重復(fù)過程,其可靠度不斷增長(zhǎng),前一增長(zhǎng)階段的可靠性信息可作為下一階段可靠性增長(zhǎng)的評(píng)定依據(jù),考慮到數(shù)據(jù)不足時(shí)先驗(yàn)分布無法精確確定,本文采用不精確Dirichlet先驗(yàn)分布族表征先驗(yàn)信息,建立了系統(tǒng)不精確可靠性增長(zhǎng)模型,并將該模型應(yīng)用到銑軸組件的固有可靠性評(píng)定中;考慮到使用可靠性與固有可靠性的耦合性,本文以固有可靠性信息為不精確先驗(yàn)信息,以使用可靠性評(píng)定為目標(biāo),建立了使用可靠性評(píng)估模型,實(shí)現(xiàn)了銑軸組件使用可靠性的評(píng)定。
[Abstract]:The heavy-duty CNC machine tool bears many industrial products and key parts of national economy and national defense safety. The quality, performance and technical level of the heavy-duty numerical control machine are the important marks to measure the industrialization level and the comprehensive economic strength of a country. With the development of the domestic heavy-duty numerical control machine for many years, some achievements have been made, but due to the insufficient scientific and technological innovation of the domestic heavy-duty numerical control machine, the lack of the basic experimental conditions, the shortage of the high-level talents, the core technology of the tip has not been broken, and the frequent occurrence of the early faults in the use process is constantly exposed, The problems of poor quality stability and high maintenance cost bring the series of difficulties and challenges to the users of heavy-duty CNC machine tools, and directly lead to the poor reliability of the domestic heavy-duty CNC machine tools, the low added value of the products, the weak industrialization ability and the non-strong international competitiveness. The reliability technology system of the present numerical control machine tool is mainly for small and medium-sized numerical control machine tools, and the research on the reliability technology of heavy-duty numerical control machine tools has not been carried out yet. Because the heavy-duty numerical control machine tool is different from the small and medium-sized numerical control machine tool in the aspect of the structure form, the processing task and the like, the existing reliability technology cannot be directly applied. Therefore, it is urgent to study the reliability technology system of heavy-duty NC machine tools for the features of the structure of heavy-duty NC machine tools. Reliability modeling and analysis are the key components of the reliability technology system of heavy-duty NC machine tools. The reliability modeling and analysis of the heavy-duty numerical control machine tool is based on the typical system reliability model under the condition that the reliability influence factors and the reliability data characteristics of the machine tool are comprehensively studied, and the structure function characteristics of the heavy-duty numerical control machine tool are combined. A mathematical model is established to analyze and evaluate its reliability. Compared with the general numerical control machine, the reliability modeling and analysis of the heavy-duty numerical control machine tool has the difficulties of complex system structure, few samples of the whole machine and the key parts, insufficient data of the test data, various reliability data types, complex fault mechanism, and the like. In view of the difficulties in the reliability research of the above heavy-duty numerical control machine tools, this paper mainly carries out the following research work: (1) taking the main shaft of the heavy-duty numerical control machine as the research object, analyzing the various uncertainty factors which influence the reliability of the main shaft of the heavy-duty numerical control machine and the limitation of the existing uncertainty quantization method, A unified quantitative framework for mixed uncertainty based on the theory of uncertain probability is constructed. In this paper, based on the theory of stress-intensity interference, a general approach to the reliability modeling of the non-precise structure of the parts of the machine tool is put forward based on the theory of stress-intensity interference. In this paper, the reliability analysis, modeling and calculation of the multiple failure modes of a heavy-duty numerical control landing gear bed are carried out in this paper. (2) The structural reliability modeling and analysis method considering the correlation of multi-failure modes is put forward under the unified quantitative framework of mixed uncertainty. The failure mode is multiple and the failure is related to the general feature of the failure of the machine tool parts. The research of the failure correlation is based on a large number of fault statistics, and the data deficiency is not taken into account, which is not in conformity with the actual data characteristics of the heavy-duty numerical control machine. In order to solve this problem, this paper introduces a correlation-based Copula function in the uncertain structural reliability model, and puts forward an improved model of the non-precise structural reliability considering the multi-failure mode, and applies the improved model to the reliability modeling and analysis of the eccentric shaft. In this paper, the correlation analysis and calculation of multi-failure mode are realized, and the necessity of considering failure in engineering practice is verified by comparing with the calculation results under the failure independent condition. (3) The reliability of the whole machine and its sub-system of the heavy-duty numerical control machine is still affected by the mixed uncertainty factors, and the failure of each subsystem is related to each other. Based on the analysis of component failure correlation, a system reliability modeling and analysis method considering the mixed uncertainty and the failure correlation is put forward, and a typical system uncertainty reliability model is established, and the system uncertainty reliability model based on the fault tree analysis is established. The main shaft system of the heavy-duty numerical control machine has a large number of components, and the fault-related analysis is carried out for each component, and the workload is great. In this paper, by means of the DEATEL method, the fault importance, the degree of the fault of the parts and components of the main shaft system are analyzed. In this paper, the precise reliability modeling and analysis of the shaft assembly is completed with the focus of the shaft assembly. (4) The reliability of the heavy-duty numerical control machine in the design and development stage through the 鈥淒esign-Test-Improvement-Redesign-Retest鈥，

本文編號(hào)：2375425