本文選題：AZ91D鎂合金 + 變速器箱體��； 參考：《濟南大學》2015年碩士論文

【摘要】：汽車正常行駛主要依靠傳動系統(tǒng)穩(wěn)定的動力輸出,在這一過程中發(fā)動機與變速器相互配合完成復雜的速度變換與動力傳遞,其中變速器的作用是將發(fā)動機的輸出動力通過飛輪、離合器等轉換為變速器的輸入轉速然后按不同的傳動比要求輸出不同的轉速以滿足不同車速、不同牽引力的工作要求,能夠使發(fā)動機發(fā)揮其最佳性能。其中變速器箱體要具有足夠的強度剛度來抵抗外載荷的作用,這是影響變速器總成可靠工作和齒輪傳動系統(tǒng)動力穩(wěn)定輸出的關鍵因素,箱體剛度不足,會引起軸承安裝位置的偏移,造成軸承的非正常磨損破壞,大大降低軸承壽命,同時引起齒輪傳動的錯位,偏載,降低齒輪壽命,增大變速器噪音;箱體強度不足,則箱體承載能力不夠,從而會引起變速器箱體撕裂破壞,影響汽車正常安全行駛。鎂合金在各金屬合金中屬于較輕的金屬結構材料,比強度大比剛度高,減震性、散熱能力好,承受沖擊載荷能力強,其中AZ91D鎂合金不僅是一種綠色環(huán)保的金屬材料,而且其具有密度低承載能力好等特點,將其應用到工業(yè)產品中可以大大降低產品質量提升產品性能;汽車工業(yè)中,汽車自身的重量是影響燃油消耗的重要因素之一,隨著我國環(huán)境問題日漸嚴峻,國家節(jié)能減排政策的不斷推出,使低碳經濟概念不斷深入人心,并且我國在輕卡行業(yè)實施的由國Ⅲ級排放標準升為國Ⅳ級以上排放標準要求,使得汽車零部件產品輕量化生產成為車企積極探索研究的重要方向。鎂合金AZ91D具有質量輕、比強度大等優(yōu)點,已經在航空領域得到了廣泛的應用并且驗證了鎂合金優(yōu)越的機械性能,同樣,將鎂合金應用于汽車領域,不僅可降低整車質量,提升車輛機動性能,而且降低油耗,節(jié)能環(huán)保,整車NVH性能也會得到顯著改善。因此,本文以AZ91D鎂合金作為變速器箱體材料,利用有限元方法對箱體結構進行模擬仿真,在保證變速器正常工作的前提下對箱體進行結構輕量化分析設計,提升變速器的使用性能,實現(xiàn)低碳、綠色環(huán)保制造。課題以MW520鎂合金輕卡變速器為研究對象,應用UG三維軟件建立了變速器的總成模型,利用HYPERMESH前處理軟件考慮各零部件之間的接觸非線性關系處理三維模型,通過控制單元的長寬比,翹曲度,雅閣比率從而建立了高質量的有限元模型,根據(jù)齒輪和傳動軸系的參數(shù)利用MASTA建立了MW520鎂合金變速器傳動系統(tǒng)有限元模型,根據(jù)汽車總成技術條件及臺架試驗標準設定了鎂合金變速器箱體一檔、倒檔工況下的轉速、運轉時間,并在一檔、倒檔工況下施加2.5倍載荷,提取了箱體在載荷作用下軸承孔處的載荷譜,利用HYPERMESH將載荷譜作為載荷邊界條件簡化施加在箱體有限元模型相應位置,利用ABAQUS軟件研究了在此兩種工況下箱體承受載荷的應力分布同時研究了變速器箱體在沖擊載荷下的應力分布情況,優(yōu)化了箱體結構局部高應力區(qū)域,對優(yōu)化后的箱體模型進行有限元數(shù)值分析,分析結果表明鎂合金AZ91D材料的變速器箱體滿足汽車正常工作要求。
[Abstract]:The normal driving of a car is mainly dependent on the dynamic output of the transmission system. In this process, the engine and the transmission cooperate with each other to complete the complex speed transformation and power transfer, in which the function of the transmission is to convert the engine's output power through the flywheel, the clutch and so on to the input speed of the variable speed device and then according to the different transmission ratio. It is required to output different speeds to meet different speed, and the work requirements of different traction forces can make the engine play its best performance. In which the gearbox should have enough strength stiffness to resist the external load, which is the key factor affecting the reliable work of the transmission assembly and the power stability of the gear transmission system. Lack of stiffness will cause the offset of bearing installation position, cause abnormal wear and tear of bearing, greatly reduce bearing life, and cause the dislocation of the gear transmission, partial load, reduce gear life and increase the noise of transmission; the box body strength is not enough, which will cause the gearbox to tear and destroy, and affect the car positive. The magnesium alloy is a lightweight metal structure material in all metal alloys, which has high specific stiffness, shock absorption, good heat dissipation and strong impact load capacity. AZ91D magnesium alloy is not only a kind of green metal material, but also has the characteristics of low density and low bearing capacity. It is applied to industrial products. In the automobile industry, the vehicle's own weight is one of the important factors affecting the fuel consumption. With the increasingly severe environmental problems in China, the continuous introduction of the national energy saving and emission reduction policy makes the concept of low carbon economy deeper and deeper, and China's implementation in the light card industry is from country III level. The emission standards have been promoted to the requirements of national level IV emission standards. The lightweight production of auto parts products has become an important direction for the active exploration and research of the car enterprises. Magnesium alloy AZ91D has the advantages of light mass and strong specific strength. It has been widely used in the field of aviation and verified the superior mechanical properties of magnesium alloy, and the same, magnesium alloy will be combined. Gold should be used in the automotive field, not only to reduce the quality of the vehicle, to improve the motor performance, to reduce fuel consumption, to save energy and environmental protection, and to improve the performance of the whole vehicle NVH. Therefore, this paper uses AZ91D magnesium alloy as a gearbox material, and uses the finite element method to simulate the structure of the box, so as to ensure the normal work of the transmission. The lightweight analysis and design of the structure of the box is carried out to improve the performance of the transmission and achieve low carbon and green environmental protection. The research object is MW520 magnesium alloy light card transmission. The model of the transmission is established by using UG 3D software, and the contact nonlinear relationship between the components is considered by the HYPERMESH pretreatment software. A high quality finite element model is established by controlling the length to width ratio, warpage and the accord ratio of the control unit. The finite element model of the transmission system of the MW520 magnesium alloy transmission is established according to the parameters of the gear and transmission shaft system using MASTA, and the speed change of magnesium alloy is set according to the technical conditions of the automobile assembly and the standard of the bench test. With one gear box, rotating speed and running time under the working condition of reverse gear, 2.5 times load is applied to the one gear and reverse gear, and the load spectrum of the bearing hole is extracted under the load of the box. The load spectrum is simplified to the corresponding position of the finite element model of the box by HYPERMESH, and the two kinds are studied by using the software of ABAQUS. The stress distribution of the box under the load under the working condition is also studied. The stress distribution of the gearbox under the impact load is studied. The local high stress area of the box structure is optimized. The finite element numerical analysis is carried out on the optimized box model. The analysis results show that the gearbox of the magnesium alloy AZ91D material meets the normal working requirements of the automobile.

【學位授予單位】：濟南大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：U463.212;TB115

【參考文獻】

相關期刊論文 前1條

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本文編號：1809841