【作者】 董成国；

【导师】 孟繁忠；

【作者基本信息】 吉林大学 ， 机械设计及理论， 2010， 博士

【摘要】 近年来,随着新型汽车发动机的不断问世和汽车链设计与制造技术的不断发展,齿形链因其具有结构紧凑、传递功率高、可靠性与耐磨性高、噪音低等显著优点,越来越广泛地应用在汽车发动机正时传动、机油泵传动、高压泵传动、共轨泵传动、平衡轴传动等场合。全球正时系统采用链传动由2006年的53%预计到2011年将上升到55%,而皮带传动由2006年的38%预计下降到2011年的34%。而目前只有国外少数工业发达国家能够生产中高速汽车发动机用新型齿形链,其拥有绝大多数的专利技术以及内部设计诀窍,其关键的设计方法和研究成果均不在公开的刊物发表,从而主导和垄断着这一领域的市场和技术,形成了国内企业生产高质量新型齿形链及其正时齿形链系统的技术壁垒。论文在国家自然科学基金项目(50275062)“新型高速齿形链啮合原理及其设计方法”和国家中小企业技术创新基金资助项目(08C26213711011)“高性能汽车发动机齿形链制造技术及系列产品”的资助和支持下,在深入分析不同啮合机制齿形链啮合线的基础上,提出了汽车发动机正时齿形链系统的设计方法,并对某款汽车发动机正时齿形链系统进行了设计计算、仿真分析及试验研究。论文在深入分析新型内啮合和内-外复合啮合齿形链啮合机理的基础上,利用微分几何和坐标变换理论分别建立了内啮合齿形链和内-外复合啮合齿形链与链轮在不同啮合阶段的数学模型,求解出两种啮合机制齿形链的啮合线。从拟合得出的啮合线可以看出:内啮合齿形链的啮合过程分为链板Ⅲ与轮齿Ⅲ的啮合过程以及链板Ⅱ的啮合定位过程;内-外复合啮合齿形链的啮合过程分为内啮合、内-外共同啮合以及外啮合定位三个阶段,其中内啮合阶段的啮合线最长。利用齿形链紧边中心线的波动量研究了新型齿形链的多边形效应,对计算得出的齿形链销轴中心运动轨迹的研究结果表明,内啮合齿形链紧边中心线的波动量仅为外啮合齿形链波动量的64.6%,内-外复合啮合齿形链紧边中心线的波动量仅为外啮合波动量的28%,表明内啮合齿形链和内-外复合啮合齿形链的多边形效应明显小于外啮合齿形链。论文在综述了国内外汽车发动机正时传动系统研究现状的基础上,阐述了正时齿形链系统在汽车发动机换气过程中的重要作用,深入分析了汽车发动机正时系统的进、排气行程以及相关的配气相位,提出了具有我国自主知识产权的汽车正时齿形链系统的设计方法,同时详细阐述了张紧装置和导向装置的关键计算方法,并根据某款汽车发动机的布置方案及性能要求,对该款发动机进行了正时齿形链系统的设计与计算,为形成具有我国自主知识产权的汽车正时齿形链系统设计理论与方法奠定了重要的基础。论文基于递归算法的多体动力学理论以及现代接触动力学,建立了汽车正时齿形链系统虚拟数字样机模型,研究了汽车正时齿形链系统在具有多约束边界条件下不同转速工况的动态特性,得出了正时齿形链系统链节的运动轨迹、链节的张力、曲轴链轮与凸轮轴链轮的传动比、张紧器柱塞与张紧板的接触力,并通过FFT变换得出链节张力和法向接触力在不同转速不同发动机谐波阶次下的动态幅值。研究成果为汽车正时齿形链系统的动态特性的仿真分析提供了科学的分析方法,也为正时齿形链系统零部件之间的接触力变化以及FFT频谱分析提供了有效的分析方法。与以往国内外学者研究所采用的质量-弹簧-阻尼单元模拟仿真结果相比,本文由于采用了更为接近实际工况的接触算法,因而研究成果更为科学、更为真实。论文首次在自主研发的国内第一台自动加载、自动变速的多轴传动汽车正时链系统试验台上对正时齿形链系统进行了各种工况的试验,利用AWA6290A实时噪声分析仪测试了正时齿形链系统在多种工况下的噪声特性。通过分析凸轮轴负载扭矩对噪声的影响,得出了随着凸轮轴负载扭矩的加大噪声值增大;研究了曲轴链轮转速对正时齿形链系统噪声的影响,分析得出随着曲轴链轮转速的增加,A计权噪声值也随着增大,并通过对三个转速下的噪声进行频谱分析,得出峰值频率与齿形链的啮合频率以及固有频率相关,利用发动机谐波分析得出了噪声波动的峰值发生在发动机9.5阶、19阶和38阶谐波,并且在链板与链轮(z1=19)的啮合频率(19阶谐波)下噪声值最大,验证了仿真结果的正确性;通过探讨张紧器油压对噪声的影响,得出在张紧器油压较低时噪声相对较大,张紧器油压在较高时在高转速下的噪声相对较小,但是过大的张紧器油压将加剧齿形链与导向板、张紧板的磨损,以及齿形链与链轮之间的磨损,故建议张紧器油压取为5bar较为适宜。同时探讨了噪声的产生机理,并提出了控制噪声的相关措施。论文利用PhotoTemp MX数码照相式红外测温仪对正时齿形链系统不同张紧器油压下进行实时温度测量,研究表明温度在两个销轴的位置表现出两个峰值的变化规律,这是由于销轴与链板配合铰链处的摩擦生热导致其温度偏高;对比分析了不同张紧器油压时的工作油温及油箱油温、回油油温,虽然油压为3bar和5bar时,其工作油温均小于允许的最高工作温度120℃,但当油压为3bar时,其油箱油温、回油油温和工作油温在稳定状态下高于油压为5bar时的温度,由此可见,润滑对于正时齿形链系统的工作可靠性有着非常重要的作用。论文的研究成果为形成具有我国自主知识产权的汽车发动机正时齿形链系统设计理论与方法奠定了重要的基础,通过动力学仿真分析和汽车发动机正时传动系统试验研究表明,论文所提出的设计方法和试验方法是科学、切实可行的。本文的研究成果加速了我国汽车发动机正时链传动系统的国产化进程,对提升相关行业和企业的自主研发能力具有非常重要的意义。更多还原

【Abstract】 In recent years, with the invention of new engines and development of design and manufacture technology, silent chain is widely used in the timing drive, pump drive, high-pressure pump drive, common rail pump drive and balancing draft drive of the automotive engines because of significant characteristics such as compact structure, high transmission power, high reliability and wear-ability and low noise. The percentage of the silent chain drive users is 53% in 2006 and increase to 55% in 2011. While the percentage of belt-drive users is 38% in 2006 and decrease to 34% in 2011. At present, only a few industrial countries overseas can produce new silent chain for high-speed automobile engines, and their own most of the patented and interior design tips, the key design methods and results are not published in journals, thus dominating and monopolizing the market and technology in this field. This phenomena causes the technical barrier of new high-quality silent chain production and silent chain system for domestic companies.This paper is sponsored by the National Nature Science Foundation of China (50275062)“Meshing mechanism and design method of new high-speed silent chain”and National Middle and little Company Technology Innovation Foundation (08C26213711011)“Manufacture technology and products of high-performance silent chain of automotive engine”, based on intensive analysis of the meshing traces of different meshing mechanisms silent chains, and puts forward the design method of auto engine timing silent chain system, and design method, simulation and experiment on one automotive engine timing silent chain system are studied.The mathematical models of inner-meshing silent chain and inner-outer compound meshing silent chain meshing with the sprocket at different meshing stages are respectively built based on the theory of differential geometry and coordinate transformation. The models are based on the study of the meshing mechanism of inner-meshing and inner-outer compound meshing. Meshing traces of two different meshing mechanism silent chains are solved. From the meshing traces of inner-meshing and inner–outer compound silent chain, it can be seen that the engagement process of inner-meshing silent chain is divided into the meshing process of plateⅢwith the teethⅢand the locating of plateⅡ, and the engagement process of inner-outer compound meshing silent chain is divided into inner meshing, inner-outer compound meshing and locating of outer meshing. The trace on inner meshing stage is the longest. The polygon effect of new silent chain according to the fluctuating quantity of the centerline of the silent chain’s tight side is studied, and the results of the traces of the chain’s pin center show that, the fluctuating quantity of the tight side’s centerline in inner-meshing is only 64.6% of which in outer-meshing, and the fluctuating quantity in inner-outer compound meshing is only 28% of which in outer meshing, it can be concluded that the polygon effect in inner-meshing and inner-outer compound meshing is better than that in outer-meshing obviously.Situations of study on auto engine timing chain system in domestic and international are summarized in this paper, and the importance of silent chain system in auto engine is described. Auto engine timing system’s intake and exhaust stroke and related phases are studied deeply. The design method of auto engine timing silent chain system is raised, and the key calculation of the tensioner and the guider are described, and designs and calculates the timing silent chain system of the engine according to the layout plan and performance requirements of the auto engine are get, and it lays an important foundation for the formation of independent intellectual property rights in silent chain system design theory and methods.The mechanism-control virtual digital prototype model of the auto silent chain system based on the multi-body dynamics theory of recursive algorithm and modern contact dynamics are built in this paper. The dynamic characteristics of the timing silent chain system in the multiple constraints boundary conditions under different speeds are studied. The trajectory, chain tension force, drive ratio of crankshaft sprocket and camshaft sprocket and contact force of the tensioner plunger and tension plate are obtained. Dynamic harmonic amplitudes of the chain tension and normal contact force at different speeds and different engine orders are also obtained. The result not only provides scientific methods for the simulation of the auto timing chain system’s dynamic characters, but also provides effective methods for the changes of contact force between different components and FFT spectrum analysis. Compared with the previous results by scholars in mass-spring-damper element simulation, the research results have more scientific and reliable for its physical access method which is more close to the actual conditions.The paper is studied on the first automatic loading, automatic transmission multi-axis drive system auto engine timing chain system test bed which is in independent research and development. With the real-time noise analyzer AWA6290A, the timing silent chain system’s noise characteristics are researched under a variety of conditions. By analyzing the load torque of the camshaft and noise, the result show that the noise increases with the increase of camshaft’s load torque. By analyzing the speed of the crankshaft sprocket and the noise of the timing chain system, the result show that weighted noise level increases along with the increase of speed of the crankshaft sprocket. According to the spectrum analysis at three different speeds, the result show that the peak frequency is related to the meshing frequency and the inherent frequency of the silent chain. By the engine spectrum analysis, the result show that the peak of the noise is the 9.5th, 19th, and 38th, and the noise value is the maximum at the meshing frequency (19th) of the chain plate and the sprocket (z1=19), which verifies the correctness of the simulation. According to the research of the oil pressure of the tensioner and the noise, the result show that the noise is relatively low when the pressure is high, but thus leading to the wear between silent chain and the guider, silent chain and the tensioner, silent chain and the sprocket, so suggested that the oil pressure takes 5bar. The mechanism of noise is researched in this paper, and method of control noise is proposed.Takes real-time temperature measurement of the timing silent chain system at low speed using PhotoTemp MX digital photography infrared thermometer when the oil pressure is 5bar and 3bar, the results shows that the temperature in the two pin showing the location changes at two peaks, this is because of the friction between the pin and the plate; the working oil temperature, the tank oil temperature and the returning oil temperature are tested under different oil pressures, at the pressure of 5bar and 3bar, though the temperatures are all under the limited 120℃, the working oil temperature, the tank oil temperature and the returning oil temperature at the pressure of 3bar are all higher than that of 5bar, so the oiling plays an important role in the reliable of the timing silent chain system.The research results play an important role in the formation of independent intellectual property rights in China in design theory and method of the auto engine timing silent chain, according to the dynamic simulation and the experiments of the auto timing silent chain, the design theory and method mentioned in this paper are scientific and reliable. The research results accelerate the domestic process of the auto engine timing silent chain system, and they have very important significance in improving the ability of independent research and design in related industries and enterprises.更多还原