- 學位論文
汽車引擎蓋板之沖壓成形模面設計
On the Die Face Design for Stamping an Automotive Engine Hood
摘要
引擎蓋板零件為汽車售後服務市場的主要產品之ㄧ，但目前引擎蓋板之模面造型設計仍需仰賴模具師傅的經驗以及石膏模面的製作，才能設計出適當的餘肉造型。其設計過程中缺乏系統化與科學化的成形分析，因此對於模面造型的設計技術無法掌握，同時設計經驗亦無法有效的傳承。目前模具工業為因應市場快速反應的需求，縮短開發時程已是各模具廠必須積極努力的方向，因此傳統經驗法則也勢必將被淘汰。市售車型隨著製造技術的進步以及消費者對於外觀的注重，使得汽車外觀越來越多樣化，而且隨車型的不同外觀差異也隨之不同，因此模具廠在面臨多樣化且複雜的產品，走向數位化及科學化乃是必然的趨勢。 本研究蒐集現有引擎蓋之特徵造型與餘肉造型，並歸納出其相對應的關係，同時利用有限元素軟體與實際載具來進行研究，探討餘肉造型設計對於成形缺陷的影響，並分析這些缺陷產生的原因。所探討模具設計參數包括：沖壓角度影響、壓料面形狀影響、分模線形狀尺寸以及阻料條，然後由模擬結果歸納出較佳的設計參數，並將這些參數訂立出其設計流程。在餘肉造型設計上，本研究由蒐集的餘肉造型歸納出影響成形性的主要參數，並探討餘肉造型對於引擎蓋模面的二次拉伸行為。 為驗證本研究所提出的設計流程，特將實際之引擎蓋板沖壓成形製程與CAE分析做驗證分析，其中包括厚度分析、應變分析以及外型分析。驗證結果證實CAE分析與實際沖壓成品相當一致，因此本研究所提出之引擎蓋設計流程與模面餘肉造型設計準則，將可提供給國內沖壓模具業者做為模具設計的參考。
並列摘要
The engine hood is one of the major outer skin panels in an automobile body structure. The commercial quality requires the engine hood being free from cracks and wrinkles. In addition, the surface stretch at the center region of the engine hood needs to meet a strength requirement. Though the stamping technology on the forming of an engine hood has been developed by both the automotive industry and die makers, the success of the die design still relies mainly on the experience of professional engineers. Also, in response to the current market trends and the consumer concerns, the engine hoods look more and more diverse, making the die design even more difficult. Since the shape of an engine hood is mainly produced in the drawing operation, the die addendum design is the key to the success of manufacturing a defect free product. In order to analyze the addendum design, the part shapes of different engine hoods were first surveyed and the geometric characteristic features were identified and categorized. The existing die addendum designs corresponding to those engine hoods collected were also reviewed and the design parameters were constructed. The finite element analysis was then conducted to simulate the drawing process of an engine hood with flat addendum die face, i.e., without die addendum design. The defects occurred in the part were examined and the factors causing these defects were then analyzed. The preliminary study was then performed to examine the influence of the process parameters, such as stamping die angle, binder surface shape, and die open line shape on the defects occurred in the part. Based on the simulation results, the optimum design for the die addendum face was then investigated. The effects of the design parameters constructed in the present study on the occurrence of the defects were then examined and a systematic design guideline was proposed. In order to validate the proposed design guideline, actual engine hoods were stamped with the dies designed according to the finite element analysis. The production part shapes, thickness distributions, and the stretch at the central region were then compared with those obtained from the finite element simulations. The consistent agreement between the product parts and the simulation results confirms the validity of the design guide proposed in the present study for stamping an engine hood.