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標題: | 鋁合金自行車前叉製程優化與輕量化分析 Process Optimization and Lightweight Analysis for Manufacturing a Bike Fork with Aluminum Alloy |
作者: | Che-Yuan Kuo 郭哲源 |
指導教授: | 陳復國 |
關鍵字: | Al6061鋁合金,有限元素法,自行車前叉製程設計,輕量化分析, Aluminum alloy 6061,Finite Element Analysis,the manufacturing process of one-piece aluminum-alloy fork,lightweight analysis, |
出版年 : | 2019 |
學位: | 碩士 |
摘要: | 自行車產品因其製程開發技術之提升以及輕量化需求之造型設計,許多自行車產品需要優化製程設計,本論文透過有限元素法軟體分析全鋁合金自行車前叉製程。不同於一般前叉焊接之模式,本論文一體成形鋁合金前叉製程包含:胚料裁切、三叉擠製、三叉反擠製、鑽孔、縮管、彎管、預成形、液壓與側推、勾爪鍛造、研磨拋光等道次。本論文首先針對三叉反擠製製程進行探討,在三叉反擠製製程中,因胚料變形量大以及胚料流動性之因素影響,使得模具受力情形與胚料成形缺陷為三叉反擠製製程中重要的因素;為了降低模具受力,以模具與胚料間的摩擦力以及芯棒沖頭造型設計進行改善;而在反擠製過程中,容易發生胚料包料的成形缺陷,亦利用芯棒沖頭之設計進行改善。
而在彎管製程中,由於為追求鋁合金前叉輕量化,在前叉叉腳彎管處,容易因厚度較薄而產生凹陷的成形缺陷;材料流動與模具造型對凹陷缺陷有顯著的影響,所以用叉腳厚度與模具設計去探討;可發現不同的叉腳厚度設計對材料流動有改善,而模具造成叉腳造型的變化越大,凹陷缺陷越明顯。最後在勾爪製程中,需要運用液壓製程與鍛造製程,液壓製程目的為將勾爪胚料補足,而再用鍛造方式將勾爪成形;在液壓製程中,需要先將勾爪的特徵造型脹形,能有效改善鍛造時產生的成形缺陷。 最後利用有限元素法分析前叉於靜態彎曲試驗與衝擊試驗,在此兩種前叉規範測試下之結果,能改善試驗結果以及最佳輕量化設計。在模擬分析試驗前,需針對實際試驗的邊界條件進行確認,因台灣自行車產業標準TBIS僅說明基本規範,細部的試驗規劃會因為各公司需求而有差異;在試驗分析結果中,靜態彎曲測試與衝擊試驗的最大拉應力均發生管頭的厚度變化處,則能知道管頭至少需要的造型尺寸;而叉腳的厚度變化處之拉應力影響較小,則能針對重量輕量化進行設計。 本論文之研究成果能提供未來一體成形自行車前叉之製程優化與輕量化設計之參考。 The escalating technology and the demand of lightweight in the bicycle industry let forming process of product needed to design an optimization.in this thesis, Finite Element Analysis was used to simulate the manufacturing process of aluminum-alloy fork. Different from general fork which was assembled by welding, the forming of one-piece aluminum-alloy fork contained many operations, including blank cutting, upsetting, backward extrusion, hole drilling, tube shrinkage, tube bending, preforming, hydraulic forming and side push, clip forging, lapping and polishing. First, the thesis focused on the forming process of backward extrusion. In this process, because of the influence of large strain and the flow in the material, the force of upper die and the defect of product were the important issue in this process. To decline the force of upper die, the friction between material and die and the model of the punch were the parameters which were needed to analysis. The defect of material folding was easily occurred, and this significant issue could be solved by using the design of the punch. In the manufacturing process of tube bending, in order to pursue the lightweight of aluminum-alloy fork, the defect of indentation was almost serious at bending area because of thin thickness. The flow of material and the modeling of die had significant influence on indentation. After simulating in different of thickness and die design, the result showed what effect could be improved. Observing the result of simulation could find that larger thickness would improve the flow of material and larger deformation would deteriorate indentation. The manufacturing process of clip consisted of hydraulic forming and forging. Because the material in the area was not enough to form the clip, the target of hydraulic forming was to complement and reserve material. In hydraulic forming, preforming the characteristic profile could improve the defects. Finally, the thesis analyzed Front Fork-Static Bending Test and Front Fork- Rearward Impact Test by used Finite Element Analysis. The target of analyzing these fork tests was to improve the consequent and found the optimization of lightweight. Before the simulation, confirming actual boundary condition of fork test was necessary. Taiwan Bicycle Industry Standard which was as known as TBIS only rule a fundamental regulation, so the detail of fork test would be different from each company demand. At the result of simulation, the maximum of tension stress was occurred at the place where thickness is mutative on head tube, and the necessary design of head tube would be known. Tension stress at the back of fork affect insignificantly, so designing the back of fork was the best way to get the optimization of lightweight. The research of the thesis could provide the reference of the manufacturing process optimization of one-piece aluminum-alloy fork and the design of lightweight in the future. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/73928 |
DOI: | 10.6342/NTU201903651 |
全文授權: | 有償授權 |
顯示於系所單位: | 機械工程學系 |
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