摘 要

凸輪（軸）是中、低速柴油機(jī)配氣機(jī)構(gòu)的關(guān)鍵零件。柴油機(jī)的連續(xù)運(yùn)轉(zhuǎn)是通過(guò)凸輪對(duì)氣門的順序啟閉、氣門開(kāi)度的規(guī)律控制，使發(fā)動(dòng)機(jī)的多個(gè)沖程周而復(fù)始、定時(shí)順序的循環(huán)完成的。凸輪機(jī)構(gòu)作為機(jī)械式信息儲(chǔ)存與傳遞的基本元件，被廣泛地應(yīng)用于各種自動(dòng)機(jī)械中。凸輪機(jī)構(gòu)可以實(shí)現(xiàn)各種復(fù)雜的運(yùn)動(dòng)要求，而且結(jié)構(gòu)簡(jiǎn)單緊湊。凸輪是內(nèi)燃機(jī)配氣系統(tǒng)的重要部件-，凸輪軸的性能將直接關(guān)系到整個(gè)內(nèi)燃機(jī)性能的好壞。
本文主要就是通過(guò)有限元分析軟件ANSYS對(duì)配氣系統(tǒng)中凸輪與挺柱之間的接觸應(yīng)力進(jìn)行分析。首先，本文回顧了以往國(guó)內(nèi)外對(duì)于凸輪的研究成果，從以往的研究來(lái)看，無(wú)論是在凸輪設(shè)計(jì)方面還是凸輪制造方面國(guó)內(nèi)都是比較落后的。然后通過(guò)經(jīng)典理論對(duì)凸輪進(jìn)行了簡(jiǎn)單的校核。在校核中，本文選取的是彈性計(jì)算方法，從計(jì)算結(jié)果來(lái)看，凸輪的性能是符合要求的。最后，本文通過(guò)建模對(duì)凸輪與挺柱之間進(jìn)行了接觸應(yīng)力分析。在分析中，本文選取的某一時(shí)刻的凸輪為研究對(duì)象，從分析結(jié)果來(lái)看，凸輪的接觸應(yīng)力在其許用值范圍之內(nèi)，符合要求。
通過(guò)分析，本文得到以下幾點(diǎn)結(jié)論：凸輪與挺柱的接觸區(qū)域近似為矩形；凸輪與挺柱接觸區(qū)域的下方產(chǎn)生應(yīng)力集中，應(yīng)力最大；凸輪軸在工作時(shí)，凸輪中心孔以及凸輪與挺柱的接觸區(qū)域產(chǎn)生應(yīng)力集中，這兩處為凸輪重點(diǎn)關(guān)注區(qū)域。


關(guān)鍵詞：凸輪軸，有限元法，接觸應(yīng)力,Ansys

ABSTRACT

Cam shaft is the key part of the middle or low speed diesel engine. The diesel engine running through the valve’s opening and closing regularly, made the diesel engine stroke working periodically. As the basic part of the message storing and transforming, cam organization is used wildly in kinds of mechanism. Cam organization can realize many kinds of complicated moving, and the composition is simple and shut tightly. Cam organization is one of the important parts of the system. The satiability of the camshaft will affect the whole diesel engine.
The article is talking about the close stress analysis of the cam and lifter of thesystem. Above all, this article recalled the research result of from home and abroad. Judging form the research before, not only the design, but also the manufacture is fall behind abroad, and then, tested through the classic theory. Among the testing, we chose the elasticity methods, looking from the results, cam’s function is coincidence. Finally, the article analyzed the close stress between the cam and the lifter through molding. Among the analysis, we chose one of the moments of the cam to research, judging from the results, cam’s close stress is compatible with the standard.
Through the analysis, we got a few of conclusions: the close areas of the cam and lifter almost like rectangle; the stress is under the place of the cam and lifter engaging areas, and the areas between the cam and lifter, the two places is the key areas of the cam.


Key Words:Cam Shaft,Finite Element Method,Conttract Stress,Ansys


目 錄

中文摘要 Ⅰ
ABSTRACT Ⅱ
1緒論 1
1.1概述 1
1.2國(guó)內(nèi)外研究現(xiàn)狀分析 1
1.2.1中、低速柴油機(jī)凸輪軸的設(shè)計(jì)研究現(xiàn)狀 1
1.2.2中、低速柴油機(jī)凸輪軸的制造研究現(xiàn)狀 3
1.3課題研究的目的和意義 5
1.4本章小結(jié) 5
2 凸輪軸及配氣機(jī)構(gòu)概述 6
2.1凸輪軸簡(jiǎn)介 6
2.2凸輪軸的一般結(jié)構(gòu) 7
2.3配氣機(jī)構(gòu)簡(jiǎn)介 8
2.3.1頂置凸輪軸式配氣機(jī)構(gòu) 9
2.3.2多氣門式配氣機(jī)構(gòu) 9
2.3.3可變氣門式配氣機(jī)構(gòu) 10
2.4本章小結(jié) 10
3 凸輪的理論校核 11
3.1剛性計(jì)算方法 11
3.2彈性計(jì)算方法 13
3.3理論校核計(jì)算 14
3.4本章小結(jié) 15
4 凸輪的靜力分析 16
4.1凸輪的三維建模 16
4.2劃分網(wǎng)格 18
4.2.1定義單元類型 18
4.2.2定義材料特性并分網(wǎng) 18
4.3施加載荷與約束 20
4.4求解并查看計(jì)算結(jié)果 20
4.5本章小結(jié) 24
5 凸輪與配氣系統(tǒng)的有限元接觸分析 25
5.1引言 25
5.2接觸分析中的有限元法 25
5.2.1有限元接觸分析 25
5.2.2有限元工具ANSYS工具軟件介紹 25
5.2.3 ANSYS主要技術(shù)特點(diǎn) 26
5.3 ANSYS接觸類型 26
5.3.1 ANSYS接觸單元 27
5.4凸輪軸的接觸分析 28
5.4.1定義單元類型及材料特性 28
5.4.2對(duì)模型劃分單元 29
5.4.3創(chuàng)建接觸對(duì) 30
5.4.4對(duì)模型施加載荷和約束并求解 31
5.4.5查看計(jì)算結(jié)果 33
5.5本章小結(jié) 38
6 全文總結(jié) 39
參考文獻(xiàn) 40
致 謝 42