摘 要

配氣機(jī)構(gòu)作為內(nèi)燃機(jī)的重要組成部分，控制著發(fā)動(dòng)機(jī)進(jìn)排氣過(guò)程，其設(shè)計(jì)合理與否直接關(guān)系到內(nèi)燃機(jī)的動(dòng)力性能、經(jīng)濟(jì)性能、排放性能及工作的可靠性、耐久性。隨著內(nèi)燃機(jī)高功率、高速化，人們對(duì)其性能指標(biāo)的要求越來(lái)越高，要求其在高速運(yùn)行的條件下仍然能夠平穩(wěn)、可靠地工作，因而對(duì)其配氣機(jī)構(gòu)提出了更高的要求。配氣凸輪型線(xiàn)是配氣機(jī)構(gòu)的核心部分，配氣凸輪型線(xiàn)設(shè)計(jì)是配氣機(jī)構(gòu)優(yōu)化設(shè)計(jì)的重要途徑之一。
文中以某摩托車(chē)企業(yè)自主開(kāi)發(fā)的125ML發(fā)動(dòng)機(jī)為優(yōu)化對(duì)象，在掌握配氣機(jī)構(gòu)設(shè)計(jì)要求、原則以及設(shè)計(jì)流程的情況下，對(duì)原始配氣機(jī)構(gòu)性能進(jìn)行了計(jì)算和分析，明確了原始配氣機(jī)構(gòu)存在的氣門(mén)豐滿(mǎn)系數(shù)偏低、氣門(mén)正負(fù)加速度過(guò)大、氣門(mén)落座沖擊力過(guò)大、凸輪與下?lián)u臂之間的接觸應(yīng)力過(guò)大等問(wèn)題，為了改進(jìn)這些缺點(diǎn)，本文進(jìn)行了配氣機(jī)構(gòu)零部件特別是配氣凸輪型線(xiàn)的改進(jìn)設(shè)計(jì)及其主要影響因素的探討，并提出了優(yōu)化設(shè)計(jì)方案，完成此配氣機(jī)構(gòu)的優(yōu)化設(shè)計(jì)。
本文運(yùn)用UG三維建模軟件建立了所設(shè)計(jì)的配氣機(jī)構(gòu)的三維實(shí)體模型，并運(yùn)用ADAMS多體動(dòng)力學(xué)仿真軟件建立了此配氣機(jī)構(gòu)的多體動(dòng)力學(xué)模型，在不同發(fā)動(dòng)機(jī)曲軸轉(zhuǎn)速的情況下，對(duì)所設(shè)計(jì)出的配氣機(jī)構(gòu)進(jìn)行了多體動(dòng)力學(xué)仿真。得出了氣門(mén)升程、氣門(mén)開(kāi)啟速度、氣門(mén)開(kāi)啟加速度、氣門(mén)間隙調(diào)整螺釘與氣門(mén)之間的作用力、氣門(mén)落座力、凸輪與下?lián)u臂之間接觸力等運(yùn)動(dòng)規(guī)律和受力情況，在對(duì)得到的數(shù)據(jù)進(jìn)行了相應(yīng)的理論分析后，根據(jù)表現(xiàn)出來(lái)的缺點(diǎn)，不斷優(yōu)化配氣機(jī)構(gòu)各個(gè)零部件的參數(shù)，以獲得具有較好的運(yùn)動(dòng)學(xué)和動(dòng)力學(xué)特性的配氣機(jī)構(gòu)。


關(guān)鍵詞：配氣機(jī)構(gòu)，凸輪型線(xiàn)，ADAMS，多體動(dòng)力學(xué)，優(yōu)化設(shè)計(jì)










ABSTRACT

The valve train is one of the most important in a internal combustion engine, which controls the inlet and intake procedure of engine, whether the performances are good or bad, that affecting the power performance, economic performance, emissions performance of the engine, as well as affecting the reliability and wear performances of the whole engine. Along with the requests of the engine's high power, super-speed, people demand a higher index. That is, when the engine runs under a high speed, it can still work steadily and dependably, which demand that the valve train system should have a high performance. Cam profile is the hard core of the valve train, which design is one of the important ways to carry out valve train optimal design.
The optimization for the object base on a 125ML engine which independent designed by some or other motorcycle corporation, in the master valve train design requirements, design principles and design flow, the original valve train have calculation and analysis in this paper, we can find the original valve train have low coefficient of gas fullness, plus or minus valve acceleration is too large, the impact force from valve seat is too large, the impact force between cam and the rocker is too large, in order to ameliorate these shortcomings, the paper take much discuss with the valve train part in particular with cam, and an optimization design have been take out, the valve train of optimal design is completed.
This paper use UG which is a three-dimensional modeling software modeling the 3D models of the valve train ,and use ADAMS which is a multi-body dynamics simulation software modeling this multi-body dynamics model, in the engine crankshaft speed under different circumstances, this paper take the valve train a multi-body dynamics simulation. We gained the lift range of valve, the speed of valve, the acceleration of valve, the impact force from valve clearance, the impact force from valve seat, the impact force between cam and the rocker, after take theoretical analysis with the data, based on the demonstrated shortcomings, this paper constantly optimize the valve train’s parameters to get a better kinematics and dynamics of the valve train.


Key words： Valve train, Cam profile, ADAMS, Multi-body Dynamics, Optimization design


目 錄

中文摘要 Ⅰ
ABSTRACT Ⅱ
1緒論 1
1.1 課題來(lái)源 1
1.2 問(wèn)題的提出及研究意義 1
1.3 摩托車(chē)配氣機(jī)構(gòu)國(guó)內(nèi)外發(fā)展、研究現(xiàn)狀 2
1.4 本文的主要研究?jī)?nèi)容 4
2 配氣機(jī)構(gòu)的機(jī)構(gòu)設(shè)計(jì) 6
2.1 嘉陵CG125發(fā)動(dòng)機(jī)配氣機(jī)構(gòu)簡(jiǎn)介 6
2.2 配氣機(jī)構(gòu)的設(shè)計(jì)內(nèi)容與要求 7
2.2.1 配氣機(jī)構(gòu)的設(shè)計(jì)內(nèi)容 7
2.2.2 四沖程發(fā)動(dòng)機(jī)配氣機(jī)構(gòu)的設(shè)計(jì)要求 8
2.3 靜態(tài)優(yōu)化設(shè)計(jì)方法 8
2.4 配氣機(jī)構(gòu)的機(jī)構(gòu)型式選擇 9
2.5 本章小結(jié) 9
3 凸輪型線(xiàn)的優(yōu)化設(shè)計(jì) 10
3.1 引言 10
3.2 配氣凸輪的設(shè)計(jì)要求 10
3.3 配氣凸輪的表示方法 11
3.4 配氣凸輪型線(xiàn)的設(shè)計(jì)準(zhǔn)則 11
3.5 凸輪型線(xiàn)的設(shè)計(jì)方法 13
3.5.1 緩沖段設(shè)計(jì)方法 13
3.5.2 工作段設(shè)計(jì)方法 15
3.6 凸輪型線(xiàn)的改進(jìn)設(shè)計(jì) 20
3.6.1 凸輪基圓半徑的確定 20
3.6.2 凸輪型線(xiàn)的設(shè)計(jì)計(jì)算 21
3.7 本章小結(jié) 28
4 配氣機(jī)構(gòu)的零件設(shè)計(jì)方法 29
4.1 氣門(mén)的設(shè)計(jì) 29
4.1.1 氣門(mén)的工作條件 29
4.1.2 氣門(mén)的設(shè)計(jì)要求 29
4.1.3 氣門(mén)的結(jié)構(gòu)設(shè)計(jì) 30
4.1.4 氣門(mén)材料 32
4.1.5 氣門(mén)的強(qiáng)化工藝 32
4.2 氣門(mén)彈簧設(shè)計(jì) 33
4.2.1 氣門(mén)彈簧的工作條件 33
4.2.2 氣門(mén)彈簧材料 34
4.2.3 氣門(mén)彈簧強(qiáng)化工藝 34
4.2.4 氣門(mén)彈簧力及尺寸的確定 34
4.2.5 氣門(mén)彈簧優(yōu)化數(shù)值計(jì)算 38
4.3 本章小結(jié) 39
5 配氣機(jī)構(gòu)動(dòng)力學(xué)分析 40
5.1 引言 40
5.2 配氣機(jī)構(gòu)多剛體模型的建立 41
5.2.1 配氣機(jī)構(gòu)幾何模型的建立 41-b..