Q276汽車(chē)發(fā)動(dòng)機(jī)曲軸連桿組設(shè)計(jì)（本科畢業(yè)論文設(shè)計(jì)）

　摘要
發(fā)動(dòng)機(jī)的曲軸連桿組是發(fā)動(dòng)機(jī)最重要的部件之一，它承受著復(fù)雜的、變動(dòng)的沖擊載荷，是發(fā)動(dòng)機(jī)設(shè)計(jì)的重點(diǎn)和難點(diǎn)，也是發(fā)動(dòng)機(jī)性能評(píng)價(jià)的重要組成部分。因此要精確的對(duì)發(fā)動(dòng)機(jī)的曲軸連桿組的運(yùn)動(dòng)做出精確的分析后，針對(duì)每個(gè)零件的受力特點(diǎn)和運(yùn)動(dòng)特點(diǎn)對(duì)零件進(jìn)行設(shè)計(jì)。傳統(tǒng)的設(shè)計(jì)方法很麻煩，而且不精確。采用C++ Builder可以自己開(kāi)發(fā)出軟件解決，解決計(jì)算中遇到的問(wèn)題。
本文針對(duì)276Q小排量汽車(chē)發(fā)動(dòng)機(jī)的重要機(jī)構(gòu)—曲軸連桿組進(jìn)行了設(shè)計(jì)研究，通過(guò)分析，確定了機(jī)構(gòu)的主要設(shè)計(jì)參數(shù)，建立了發(fā)動(dòng)機(jī)曲軸連桿組的分析模型，推導(dǎo)出滑塊（活塞）的位移、速度、加速度、慣性力等的數(shù)學(xué)模型，用C++編寫(xiě)出活塞在每個(gè)轉(zhuǎn)角的位移、速度、加速度、慣性力的計(jì)算程序，并導(dǎo)出其它零部件的運(yùn)動(dòng)，為機(jī)構(gòu)動(dòng)力分析提供了計(jì)算慣行載荷和位置分析數(shù)據(jù)。在分析發(fā)動(dòng)機(jī)燃燒過(guò)程的基礎(chǔ)之上，獲得了發(fā)動(dòng)機(jī)工作全過(guò)程作用在活塞上的的輸入載荷隨曲柄轉(zhuǎn)角變化的歷程。根據(jù)求得的外載荷進(jìn)行載荷組合，為結(jié)構(gòu)強(qiáng)度設(shè)計(jì)提供了載荷計(jì)算依據(jù)。在完成結(jié)構(gòu)設(shè)計(jì)的基礎(chǔ)上，在對(duì)重要零件的公差與配合進(jìn)行選擇計(jì)算，并繪制出用于加工制造的圖紙。
本畢業(yè)設(shè)計(jì)課題的研究與實(shí)施，應(yīng)用和加深了本科學(xué)習(xí)期間的大部分理論知識(shí)，還獲得了很多新的理論知識(shí)，更重要的是將理論與工程設(shè)計(jì)緊密結(jié)合，增強(qiáng)了分析問(wèn)題和解決問(wèn)題的能力，對(duì)知識(shí)的綜合運(yùn)用和解決工程中的實(shí)際問(wèn)題，在能力上獲得了很大的提高，并得到了全面的鍛煉。

關(guān)鍵詞：汽車(chē)發(fā)動(dòng)機(jī)，發(fā)動(dòng)機(jī)設(shè)計(jì)，曲軸連桿組
 
ABSTRACT
The crankshaft-link group is one of the most important engine’s components, which sustains the complex and changeable impulse. It is the key point and difficulty of the engine design, and also an important part to eva luate engine’s performance.  So after accurate analysis motion of the crankshaft-link group, the parts should be designed according to its characteristics of the force and movement. The traditional design approach is inconvenient and imprecise.  The Problems encountered in calculation can be solved through the software developed with C++ Builder.
The paper is mainly about the design and research of crankshaft-link group, the main mechanism of the 276Q automobile (with low emission) engine. Trough the analysis of the main design, the Main design parameter was determined, and the analysis model of the crankshaft-link group was established. And people can deduce the mathematical model of the physical variables of the piston, such as displacement, velocity, acceleration, or inertia force and so on.  So people can write the program of these variables of the piston in every corner, and deduce the movement situation of other parts. All these provide the foundation of computing inertia load and the analysis of the displacement for the body dynamic analysis. Based On the analysis of engine combustion, people can observe input load of the piston changed with the change of the crank angle.  And then combine the load according to the extra load which has been gained, so as to provide a basis of load computing for the design of structural strength. After the structural design, the tolerance and cooperation of the parts will be chosen and calculated. Finally, make a drawing of parts for the processing.
During the research, implementation and the application of this graduate program what I get not only the deep understanding of most theoretical knowledge which learn in undergraduate, but also acquire much new theoretical knowledge. And the most important is my theoretical knowledge is closely integrated with engineering design and  it improve my comprehensive ability of problem-analyzing ,problem-solving and the comprehensive use of knowledge  to resolve the practical problems in the processing.

Keywords: automobile engine, engine design, crank connected rod group

目   錄

中文摘要 Ⅰ
ABSTRACT Ⅱ
1緒論 1
  1.1國(guó)內(nèi)外研究現(xiàn)狀綜述 1
  1.2主要研究?jī)?nèi)容和意義 2
  1.3本文的主要工作 2
 2發(fā)動(dòng)機(jī)曲柄連桿組動(dòng)力學(xué) 3
   2.1發(fā)動(dòng)機(jī)燃燒過(guò)程分析 3
 2.2發(fā)動(dòng)機(jī)曲柄連桿組運(yùn)動(dòng)學(xué)分析 4
 2.3發(fā)動(dòng)機(jī)曲柄連桿組動(dòng)力學(xué)分析 5
    2.3.1 缸內(nèi)氣體力 5
    2.3.2 活塞慣性力 6
    2.3.3 汽體力與活塞慣性力合成 6
    2.3.4 曲柄連桿組外力 9
    2.3.5 活塞連桿組力分析 9
    2.2.6 曲柄力分析 10
    2.2.7 輸出扭矩與功率 10
 2.4本章小結(jié) 11
 3曲柄連桿組計(jì)算機(jī)輔助設(shè)計(jì)及CAD軟件開(kāi)發(fā) 12
 3.1用Borland C++ Builder編制分析軟件界面 12
 3.2用Borland C++ Builder編制分析軟件程序 13
 3.3本章小結(jié) 22
 4曲柄連桿組零件設(shè)計(jì) 23
 4.1曲軸的設(shè)計(jì) 24
 4.2連桿的設(shè)計(jì)及較核 24
    4.2.1 連桿的材料選擇和尺寸的確定 24
4.2.2 連桿強(qiáng)度計(jì)算 25
 4.3連桿螺栓的設(shè)計(jì) 27
 4.4活塞的設(shè)計(jì) 27
    4.4.1活塞材料選擇和設(shè)計(jì)要求 27
    4.4.2 活塞尺寸的確定 28
4.4.3 活塞計(jì)算強(qiáng)度較核 28
 4.5活塞銷(xiāo)的設(shè)計(jì) 29
    4.5.1活塞銷(xiāo)的設(shè)計(jì)要求 29
    4.5.2 活塞銷(xiāo)的設(shè)計(jì)計(jì)算 29
 4.6滑動(dòng)軸承的設(shè)計(jì) 30
 4.7本章小結(jié) 31
5公差與配合的選擇 32
 5.1 活塞與汽缸孔的配合 32
 5.2 活塞與活塞環(huán)的配合 33
 5.3 活塞銷(xiāo)與活塞以及連桿小頭孔的配合 33
 5.4 連桿大頭兩側(cè)與曲軸連桿軸頸開(kāi)檔的配合 35
 5.5 連桿大頭孔與連桿軸瓦以及曲軸連桿軸頸的配合 35
6設(shè)計(jì)圖紙說(shuō)明 38
 6.1曲軸圖紙說(shuō)明 38
 6.2 軸瓦圖紙說(shuō)明 38
 6.3 活塞銷(xiāo)圖紙說(shuō)明 39
 6.4 連桿體圖紙說(shuō)明 39
 6.5 連桿蓋圖紙說(shuō)明 40
 6.6 連桿體的裝配圖紙說(shuō)明 40
7結(jié)論 41
參考文獻(xiàn) 42