發(fā)布時(shí)間：2018-04-30 21:03

  本文選題：水輪機(jī)組 + 組合機(jī)床�。� 參考：《湖南大學(xué)》2014年碩士論文

【摘要】：大型水電站水輪機(jī)組由于檢修時(shí)間和現(xiàn)場(chǎng)環(huán)境的限制，對(duì)水電站機(jī)組的轉(zhuǎn)輪、底環(huán)、座環(huán)等大型結(jié)構(gòu)部件的修復(fù)，提出了智能化程度高的現(xiàn)場(chǎng)修復(fù)理念。這不僅可以克服機(jī)組局部修補(bǔ)精度不高的問(wèn)題；而且還可以節(jié)省大量的人力物力資源，所以設(shè)計(jì)制造現(xiàn)場(chǎng)水電機(jī)組修復(fù)的數(shù)控多功能組合機(jī)床非常有必要。大型水電站機(jī)組現(xiàn)場(chǎng)檢修的數(shù)控多功能組合機(jī)床結(jié)構(gòu)復(fù)雜，該機(jī)床的剛度和振動(dòng)頻率等機(jī)械性能關(guān)系到機(jī)床的加工精度、加工效率和工件表面粗糙度，關(guān)系到機(jī)床的安全可靠性及使用壽命。有必要對(duì)該機(jī)床床身結(jié)構(gòu)等進(jìn)行動(dòng)靜態(tài)分析，，找出機(jī)床床身的最大變形處和最大應(yīng)力；通過(guò)模態(tài)分析可以判斷振型是否影響該機(jī)床加工精度；這樣可以對(duì)機(jī)床床身相關(guān)的部位進(jìn)行優(yōu)化設(shè)計(jì)來(lái)改進(jìn)性能。所以本文的研究具有重要的理論與工程意義。 本文對(duì)國(guó)內(nèi)外數(shù)控機(jī)床結(jié)構(gòu)有限元分析與結(jié)構(gòu)優(yōu)化研究的現(xiàn)狀與發(fā)展做了全面深入的評(píng)述。對(duì)ANSYS Workbench平臺(tái)建立機(jī)床結(jié)構(gòu)有限元分析模型做了闡述。本文對(duì)水輪機(jī)轉(zhuǎn)輪底環(huán)止漏環(huán)現(xiàn)場(chǎng)加工時(shí)的專用組合機(jī)床結(jié)構(gòu)進(jìn)行有限元靜力分析與振動(dòng)模態(tài)分析；在此基礎(chǔ)上對(duì)機(jī)床結(jié)構(gòu)進(jìn)行了優(yōu)化改進(jìn)，并且對(duì)優(yōu)化后的機(jī)床結(jié)構(gòu)進(jìn)行了有限元靜力分析與振動(dòng)模態(tài)分析。機(jī)床結(jié)構(gòu)優(yōu)化改進(jìn)后整個(gè)機(jī)床的靜動(dòng)態(tài)特性都有了明顯提高，機(jī)床總體變形和各個(gè)方向的變形有了較為明顯的改善，應(yīng)力集中也有明顯的改善，靜態(tài)性能有了顯著提高，機(jī)床結(jié)構(gòu)剛度分布較合理；機(jī)床固有頻率和模態(tài)振型也有一定的改善。其次，針對(duì)水電機(jī)組轉(zhuǎn)輪下環(huán)現(xiàn)場(chǎng)加工數(shù)控組合機(jī)床的懸臂系統(tǒng)，分析計(jì)算該加工工況下機(jī)床的變形及應(yīng)力，并以機(jī)床設(shè)計(jì)部門提出的機(jī)床刀尖處綜合變形0.15mm為目標(biāo)，提出機(jī)床結(jié)構(gòu)的改進(jìn)措施，增強(qiáng)該機(jī)床懸臂系統(tǒng)剛性，減小機(jī)床在受切削力時(shí)的結(jié)構(gòu)變形，提高機(jī)床加工質(zhì)量；提出了適當(dāng)降低機(jī)床切削力的方案。最后，對(duì)大型水電站水電機(jī)組轉(zhuǎn)輪現(xiàn)場(chǎng)檢修加工數(shù)控專用組合機(jī)床進(jìn)行了靜特性和振動(dòng)模態(tài)有限元分析。分析結(jié)果認(rèn)為機(jī)床刀架刀夾附近剛度需要加強(qiáng)；機(jī)床刀架立柱的軌道處安裝刀具，因此該處的各方向有限元變形是影響加工精度的重要因素，要引起重視。機(jī)床垂直連接臂和刀架部分是薄弱環(huán)節(jié)，影響加工精度，需要改進(jìn)提高其固有頻率。
[Abstract]:Due to the limitation of maintenance time and field environment, the paper puts forward a high intelligent field repair idea for large structural parts such as runner, bottom ring, seat ring and so on. This can not only overcome the problem of low repair accuracy, but also save a lot of manpower and material resources, so it is necessary to design and manufacture the NC multifunctional machine tool for the repair of hydropower units. The structure of NC multifunctional machine tool for on-site maintenance of large hydropower station unit is complex. The mechanical properties such as rigidity and vibration frequency of the machine tool are related to the machining accuracy, machining efficiency and surface roughness of the workpiece. Related to the safety and reliability of machine tools and service life. It is necessary to make dynamic and static analysis on the structure of the machine bed, to find out the maximum deformation and stress of the machine bed, and to judge whether the mode shape affects the machining accuracy of the machine by modal analysis. In this way, the machine bed related parts can be optimized to improve the performance. Therefore, the study of this paper has important theoretical and engineering significance. The present situation and development of finite element analysis and structural optimization of CNC machine tools at home and abroad are reviewed in this paper. The finite element analysis model of machine tool structure based on ANSYS Workbench platform is described. In this paper, the finite element static analysis and vibration modal analysis are carried out for the structure of the special composite machine tool, which is used in the field processing of the leakage ring of the bottom ring of the runner of a hydraulic turbine, and the structure of the machine tool is optimized and improved. The finite element static analysis and vibration modal analysis of the optimized machine structure are also carried out. The static and dynamic characteristics of the whole machine tool have been improved obviously after the optimization and improvement of the structure of the machine tool, the overall deformation of the machine tool and the deformation in all directions have been obviously improved, the stress concentration has also been obviously improved, and the static performance has been remarkably improved. The stiffness distribution of machine tool structure is reasonable, and the natural frequency and modal mode of machine tool are also improved. Secondly, aiming at the cantilever system of NC combined machine tool which is machined by the lower ring of the runner of hydropower unit, the deformation and stress of the machine tool under the working condition are analyzed and calculated, and the target is the comprehensive deformation 0.15mm at the cutting tip of the machine tool proposed by the machine tool design department. The improvement measures of the machine tool structure are put forward to enhance the rigidity of the cantilever system of the machine tool, to reduce the structural deformation of the machine tool under the cutting force, and to improve the machining quality of the machine tool, and the scheme to reduce the cutting force of the machine tool is put forward. Finally, the static characteristics and vibration modal finite element analysis of the NC machine tool for the field maintenance and processing of the runner of the large hydropower station are carried out. The analysis results show that the stiffness near the tool holder needs to be strengthened, and the tool is installed in the track of the tool holder column, so the finite element deformation in all directions is an important factor affecting the machining accuracy, which should be paid more attention to. The vertical connecting arm and the tool holder are weak links, which affect the machining accuracy and need to be improved to improve the natural frequency.
【學(xué)位授予單位】：湖南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TK730.8

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