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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/72367


    Title: 以數值模擬與實驗驗證研究 精密深溝滾珠軸承多道次溫間鍛造製程 -缺陷分析與模具設計合理化;Numerical analysis and experimental validation on multi- stage warm forging process of deep groove ball bearing --- defect analysis and tooling design rationalizationNumerical analysis and experimental validation on multi- stage warm forging process of deep groove ball bearing --- defect analysis and tooling design rationalization
    Authors: 黃傑泓;Huang,Jie-Hong
    Contributors: 機械工程學系
    Keywords: 軸承;熱/溫間鍛造;有限元素分析;鍛造實驗;整體結構;Ball bearing;Hot/Warm forging;Finite element method;Experiment;Structural integrity
    Date: 2016-07-06
    Issue Date: 2016-10-13 14:50:39 (UTC+8)
    Publisher: 國立中央大學
    Abstract: 本論文研究多道次溫鍛軸承模擬以及實驗分析,配合溫鍛模擬數值以及實驗結合,使模具合理化,分析鍛件產品不良品可能原因,設計變更模具,有效提升軸承產
    量及穩定度,降低不良率發生,並延長模具壽命。 除此之外,為了瞭解到模擬與實際鍛件設計上的差異與情況,在執行每一階段的鍛造,保留每個階段性的鍛品與模擬情況作比對分析,比對三維/二維有限元素分析,謹慎地執行模擬與試驗的研究比較。
    深溝滾珠軸承精密鍛造過程中,以成形鍛道次之完成鍛鍛造為最重要,其成形段道次的成形狀況,將直接影響到後製程的精度調整,與最終鍛品的精度情況;一般而言,軸承熱鍛成形時,常見的缺陷狀況有褶皺、偏料、不飽和、過飽和、外觀成形不良以及夾料等不良情況發生。因此透過模擬分析提早發現設計不良原因探討,淘汰不良品,並利用有限元素分析有效預測出材料偏移及模具偏心情況的發生、材料流動性不佳、模具冷卻水流量因素與材料體積控制等研究,研究出最佳化鍛件成形狀況,有效提升模具壽命以及鍛件產量。透過模擬分析發現鍛造缺陷在製程中發生原因探討,利用有限元素分析預測材料偏移情形、材料流動皺摺原因與材料體積不足等影響鍛品成形性未完全等充填問題。數值模擬結果表明,其設計之上沖頭的幾何形狀,上沖頭圓角(R2)設計與倒角(C2)設計上,其鍛造過程中,顯示不同的變形率(有效應變/有效應力分佈)和材料流動形態,模擬之準確性與實際鍛品比對驗證下所得之研究成果,對於鍛品的成形有明顯之差異。

    此外,數值模擬和實驗驗證過程中其詳細的模具設計和尺寸的變化,在鍛品及沖頭的整體結構完整性上,對於鍛造過程,其穩定性上是相當重要的。此外,鍛造上所產生之廢料比,其所鍛造之方式產生之內外環上,可減少之廢料佔整體棒材體積而言約9%左右。再者,在其多道次溫鍛過程中其模具鍛造產量可達每小時10,000件內外環,而在整體鍛造上其鍛品具有完整之結構穩定性。
    ;In this study, a multi-stage warm forging process for making bearing rings is numerically and
    experimentally investigated. The aim of the study is to determine the crucial station of the finishing forging process such that the tool wear is prolonged and tool fracture should be minimized. In addition, in order to ensure the appropriateness of the suggested modification, a 3-dimensional finite element simulation on each sequence is performed, and carefully compared with experimental investigations.
    Numerical simulations results indicate that the redesigned upper punch geometry, radius(R2) of the finishing forging process, demonstrates drastically different deformation rate (the effective strain/effective stress distribution) and material flow pattern, as compared with chamfer (C2) counterpart. Accuracy of the numerical models has been verified by comparing with experimental measurements . In addition, the numerically and experimentally validated process includes the detailed tooling design and dimension variation, which is of great importance in maintaining the overall structural integrity of the forging die/punch and thus, the stability of the whole process. Concerning on the waste ratio comparison, the method used steel rods are as raw material and the IR/OR rings form is given by hot/warm forging and sequential cold rolling processes and the waste ratio decreases to ~9%. Finally, it is shown that the multi-stage warm forging process in this study could be successfully applied to the high-quantity production (10,000 pieces/hr) of the IR/OR of the deep groove ball bearing with the stability and structural integrality of the whole process.
    Appears in Collections:[機械工程研究所] 博碩士論文

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