避振彈簧參數設定對麥花臣式汽車前避震器耐久性之影響研究

The optimal parameters setting of damper spring to improve durability for the Mac Pherson front shock absorber

楊文龍(Wen-Lung Yang)

指導教授 ： 陳永樹

元智大學/工程學院/機械工程學系/碩士(2008年)

摘要

近年來，麥花臣式(Mac Pherson )獨立懸吊(Independent Suspensions)系統廣泛應用於輕型房車與休旅車上。此種獨立懸吊系統除了節省非獨立懸吊所需之上固定臂之空間以外，當車輛行經跳動路面時,亦可同時增加輪胎與地面之接觸，吸收來自地面的反作用力，提高乘客舒適感。
但使用麥花臣式獨立前懸吊系統設計的車輛，在行駛一段里程後，前避振器在保固期內經常發現有滲油之現象。因此，國內汽車製造業者通常會依其設計經驗，針對前避震彈簧之節距、彈簧長度與圈數等參數，在維持設計圖面規格的前提下，進行適度之調整並進行耐久測試，來驗證改善是否有效。本研究藉由相關理論及軟體工具之輔助，提出可行的彈簧參數變更方法，其目的在於降低彈簧製造成本,同時達到產品符合最佳化參數設定。
此外，在獨立懸吊系統的設計中，為了改善轉向時輪胎與地面的抓地力、方向盤轉向自行回復中心以及車輛直行之穩定性，在前避震器之組裝同時會有外傾角(Camber Angle)與後傾角(Caster Angle)之角度設計考量，本研究亦探討此類設計角度與前避震器圈狀彈簧力中心偏移量之關係，以確保使用此類懸吊系統之車輛行駛中的穩定性。

關鍵字

獨立懸吊 ； 麥花臣式避震器 ； 阻尼 ； 避震彈簧 ； 彈簧參數

並列摘要

Recently, the Mac Pherson independent suspension systems have been adopted popularly on light sedans and luxury vehicles. This kind of design can overcome the space insufficiency problem for installing the upper links, such as that on those non-independent suspension systems, in the limited engine compartment. The design can also help to improve the true contact of tires with road surfaces when driving on rough roads. As a result, the system has advantages in providing better riding comforts by absorbing vibrations effectively.
However, the oil leakage on some front struts is often observed in the Mac Pherson independent system after driving certain miles even it is still in guarantee period such as that on new cars. Thus, the spring suppliers always try to modify some of the spring parameters (e.g. pitch, length, and coils) to overcome this problem. They attempt to change these parameters based on their experiences while keeping design specifications. Later, it is followed by conducting a spring durability test for the validation purposes. For all these reason, this study aims to establish the optimal spring parameters for the above mentioned purposes based on fundamental theories and using the commercial software in finite element analysis.
Besides, there are camber and caster angles designed on the independent suspension system for better control of the car on the following features: the steering wheel’s self-return function after turning, the straight-trace control when driving on a straight road, and the improvement of the tire’s contact with road surfaces. However, how these designed angles affect the offset of the resultant spring force are also investigated correspondingly. Hence, the presented results can provide the spring manufacturer better know-how on tuning the spring and improve the reliability of the spring on the suspension system.

並列關鍵字

independent suspension system ； Mac Pherson Strut ； damper ； coil spring ； spring parameter

參考文獻

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