【作者】 王文成；

【导师】 刘晓论；

【作者基本信息】 吉林大学 ， 机械设计及理论， 2014， 博士

【摘要】 随着汽车工业的发展，汽车装配线上用的传统链式输送机的性能已经无法满足汽车装配速度和装配质量提高。现有的汽车装配线上的链式输送机均采用双节距滚子输送链作为牵引件和承载件。由于双节距滚子输送链系统自身结构的限制，随着装配速度的提高，噪声大、磨损剧烈、稳定性差以及由于其内节内宽大于零件尺寸导致整线卡机等问题相继出现，严重影响了装配线的装配速度和装配质量。齿形链传动系统具有高速、低噪声、低磨损、高稳定性等诸多优点，被广泛的应用于传动领域，但是由于其自重过大，应用于输送机中时，会造成较大的冲击、噪声和振动，影响输送性能。因此，研究如何降低齿形链的自重，使其可以应用在链式输送机上，以满足链式输送机对输送速度、位置精度、稳定性和环境友好性等方面的要求，具有重要的理论研究价值和工程应用意义。本文首先介绍了链传动技术与链式输送机在各领域的应用情况以及它们的国内外发展现状，突出强调了输送链在链式输送机中的重要作用，以及链式输送机在国民经济中的重要作用，反映出本文对双节距变节距齿形输送链研究的学术价值和实际工程意义。通过分析齿形链无法应用于链式输送机中的原因，在国内外学者对齿形链研究的基础上，基于传统齿形链的结构，首次提出了适用于链式输送机的双节距变节距齿形输送链的结构。本文首次提出了双节距变节距齿形输送链的结构。该链条具有内-外复合啮合机制，采用对滚式铰链，围链节距是传统齿形链的两倍，工作链板具有三个齿，其中两侧齿为工作齿，中间齿为减磨齿；给出了工作链板、铰链、边板和导板的主要设计参数及其计算方法，且根据工程实际，设计了新型的齿形链连接接头；根据啮合和滚切原理，建立了双节距变节距齿形输送链—单节距齿形链—链轮滚刀—渐开线链轮的啮合设计体系，研究了双节距变节距齿形输送链与渐开线链轮的主要设计参数之间的耦合关系。以节距P=25.4mm，链轮齿数z=38为例，利用CAD软件绘制了二者的图纸，二者围啮良好；制造样链，进行称重试验和拉断试验，对数据整理后发现，在等抗拉载荷条件下，双节距变节距齿形输送链与传统齿形链相比，单位长度质量降低了30%以上。从而，验证了双节距变节距齿形输送链与链轮设计方法的合理性与正确性。成功将内-外复合啮合机制引入到双节距变节距齿形输送链中，深入分析了双节距变节距齿形输送链与渐开线链轮的内-外复合啮合过程，得出了其啮合周期为4z，且可以划分五个阶段：当前链节的内啮合阶段→前一链节的外啮合定位阶段→当前链节悬浮阶段→下一链节的内啮合阶段→当前链节的外啮合定位阶段；利用平面坐标变换原理，建立了双节距变节距齿形输送链系统的啮合数学模型，确定了双节距变节距齿形输送链与渐开线链轮的初始啮合位置、交变位置以及定位位置。在双节距变节距齿形输送链啮合机理研究的基础上，对其结构特性、运动不均匀性和啮合冲击特性进行了理论分析和仿真研究。结果表明：双节距变节距齿形输送链的内-外复合啮合机制、变节距特性和变节圆特性使其多边形效应、运动不均匀性和啮合冲击力与双节距滚子输送链相比均明显降低。在相同的仿真条件下，与双节距滚子输送链相比，其紧边横向波动量降低了24.18%，水平运动速度不均匀性降低了45.61%，从动轮转速不均匀性降低了23.13%，啮合冲击力降低了52.06%。可以推知：双节距变节距齿形输送链的输送位置准确度优于双节距滚子输送链。针对汽车装配线用水平式输送机，建立了双节距变节距齿形输送链的受力情况数学模型，对其运动过程中的静载荷和附加动载荷进行了理论分析，并与双节距滚子输送链进行了对比。结果显示：双节距变节距齿形输送链的静载荷除了包括传统系统的齿形链系统的静力，还包括链条与导轨之间的摩擦力；由于运动不均匀性引起的动载荷明显低于双节距滚子输送链。可以推知：双节距变节距齿形输送链的受力情况优于双节距滚子输送链。利用封闭力流式试验台对双节距变节距齿形输送链系统和双节距滚子输送链系统进行台架试验，对比分析了二者的噪声性能和磨损性能。结果表明：在转速为200r/min，加载2kN时，与双节距滚子输送链系统相比，双节距变节距齿形输送链系统的噪声降低了3.5dB，且随着转速提高，噪声降低量增大；相同转速条件下，双节距变节距齿形输送链系统的噪声波动量为双节距变节距齿形输送链系统的33%左右；经过250h的磨损试验后，双节距变节距齿形输送链的磨损伸长量仅为0.182%，与双节距滚子输送链相比，其磨损伸长率降低了的45.5%。可见：与双节距滚子输送链相比，双节距变节距齿形输送链的噪声低、耐磨损以及具有高稳定性和环境友好性。将双节距变节距齿形输送链安装在汽车装配线用链式输送机上，对其进行了为期40周的现场磨损试验，结构表明：双节距变节距齿形输送链在经过40周的现场磨损后，磨损状况良好，磨损伸长率仅为0.13%，链式输送机运行良好。可以证明其结构的合理性以及应用于链式输送机中的可行性。综上所述，本文研究的双节距变节距齿形输送链与传统齿形链相比,单位长度质量明显降低；与双节距滚子输送链相比,具有更高的位置精度、更高稳定性和环境友好性，适合应用在链式输送机中。本文得到了国家总装部项目“CDX01项目链传动系统降噪”的支持。更多还原

【Abstract】 As the development of automobile industry, the performance of traditional chainconveyor for automobile assembly line has been unable to meet requires of automobile’sassembling speed and quality. In the automobile assembly line, the chain conveyors almostall adopt double-pitch roller conveyor chain as the traction and carrying components.Because of the constraints of the structure, as the increase of assembly speed, the highernoise, severe abrasion, the conveyor was locked since the dimensions of parts was smallerthan the width of inner-link and other problems appeared in succession, which affectsautomobile assembly line’s assembly speed and assembly quality. Traditional silent chainhas a lot of advantages such as high-speed, low noise, low wear, high stability, and so on,and has been widely used in various transmission fields. But when it is used in theconveyor chain, since its heavy self-weight, there will result in great impact, large noiseand severe vibration which seriously affect chain conveyor’s delivery performance. So, ithas important theoretical value and engineering application significance that research howto reduce traditional silent chain’s self-weight and make it can be applied in the chainconveyor to meet the chain conveyor’s new requirements about delivery speed, reliabilityand environmental friendliness.Firstly, this paper described application and research status of chain transmission andchain conveyor in various fields, emphasized the important role the conveyor chain playedin chain conveyor and the important role the chain conveyor played in the nationaleconomy, which reflects the academic value and practical significance of the research ofdouble-pitch variable-pitch silent conveyor chain (short for double-pitch silent chainbelow). By analyzing the cause of why silent chain can’t be applied in chain conveyor andbased on the research achievements home and aboard, this project proposed the structure ofdouble-pitch variable-pitch silent conveyor chain which is suitable for chain conveyor.A new type of double-pitch silent conveyor chain with inner-outer compound meshingmechanism and rocker-pin joint was proposed for the first time in this paper. The chainplate has three teeth, teeth on both sides are work teeth and middle tooth is used to decreasethe wear between the top toe of chain plate and the track. The main technical parametersand its calculation method were given. And a new type of silent chain connector wasdesigned for being easily assembled. Based on the meshing theory and generating method,the meshing design system of double-pitch silent chain—traditional silent chain—hob—involutes tooth profile sprocket was established, and studied on the coupling relationsbetween the main design parameters of double-pitch silent chain and involutes profilesprocket. Take the double-pitch silent chain system for an example whose pitch is25.4 millimeter and number of sprocket is38, the blueprints had been drawn using CAD soft,and found that the system mesh good. Though weighing test and pull off test, it was foundthat under the condition of equal tensile strength, compared with the traditional silent chain,the self-weight of double-pitch silent chain reduced more than30%. Thus, it verified thecorrect of the design method of double-pitch silent chain and sprocket.The inner-outer compound meshing mechanism was firstly introduced into thestructure of double-pitch silent chain. And then the meshing process of double-pitch silentchain and involutes tooth profile sprocket was deeply analyzed. The analysis results showthat the meshing cycle time was4z, and could be divided into five stages: the innermeshing stage of current chain link→the outer meshing and position stage of previouschain link→the floating stage of current chain link→the inner meshing stage of next chainlink→the outer meshing and position stage of current chain link. Using the planecoordinate transformation principle, the mathematical meshing model of double-pitchsilent chain and involutes tooth profile sprocket was created. And by calculating, the Initialmeshing position equation, the final location equation and the inner and outer meshingalternating position equation were all determined.Based on the research of meshing mechanism of double-pitch silent chain, Theoreticalanalysis and simulation studies on the structural feature, the motion unevenness andmeshing impact feature were implemented. The results showed that the double-pitch silentchain has variable pitch feature and variable pitch cycle feature, which make the Polygoneffect, motion unevenness and impact force significantly reduced. Under the samesimulation conditions, compared with double-pitch roller conveyor chain, the double-pitchsilent chain’s tension side lateral fluctuates reduced24.18%, the unevenness of horizontalvelocity reduced45.61%, the unevenness of driven sprocket’s angular velocity reduced23.13%and meshing impact force reduced52.06%. According to the results, it can bededuced that the double-pitch silent chain play a better conveying performance thandouble-pitch roller conveyor chain.Because of the chain conveyor in automobile assembly line is horizontal, the forcemathematical model of horizontal double-pitch silent chain system was build, and thentheoretical analysis about static load and dynamic load during movement were carried out.The analysis results show that the static load of double-pitch silent conveyor chain containsfriction between the chain and the guide rail besides centrifugal force、chain tension and soon; the additional dynamic load caused by motion unevenness is significantly lower thandouble-pitch roller conveyor chain’s. So it can be seen that the forces situation ofdouble-pitch silent conveyor chain is better than double-pitch roller conveyor chain.Compare tests were carried out to compare the noise feature and wear resistance feature between double-pitch silent conveyor chain system and double-pitch rollerconveyor chain system by closed power flow chain test bench. The test results show thatwhen the rotating speed is equal to200rpm, load is equal to2kN, compared todouble-pitch roller conveyor chain system, the noise of double-pitch silent conveyor chainsystem reduced3.5dB, and with the increase of rotating speed, the noise reduction amountincrease significantly, when the two system under the same rotating speed, and thedouble-pitch silent conveyor chain system’s noise fluctuations is only about double-pitchroller conveyor chain system’s33%; After250hours wear test, Wear elongation rate ofdouble-pitch silent chain is only0.182%, which is only54.5%of that of double-pitch rollerconveyor chain’s. therefore, it can be concluded that compared to double-pitch rollerconveyor chain, the double-pitch silent chain has the advantages of lower noise, higherwere resistance, better reliability and environmental friendliness.The double-pitch silent chain was assembly in the chain conveyor, which is used inthe automobile assembly line, and the40weeks filed wear test was made. The test resultshow that after40weeks filed wear test, the double-pitch silent chian weared slightly, wearelongation rate is only0.13%and the chain conveyor rans well. That can prove thereasonableness of its structure and the feasibility it is used in chain conveyors.In summary, the double-pitch silent chain proposed in this paper, compared withtraditional silent chain, has a lighter self-weight, compared with double-pitch rollerconveyor chain, and has more accuracy delivery position, better reliability andenvironmental friendliness. It is more suitable for application in chain conveyor.This project is supported by national general equipment department project “CDX01Project the noises reduce of chain drive system”.更多还原