【作者】 胡军；

【导师】 徐燕申；

【作者基本信息】 天津大学 ， 机械制造及自动化， 2002， 博士

【摘要】 为了解决夏利轿车发动机TJ370Q和TJ376Q中所装配的锻钢镀硬铬气门摇臂所存在的转动惯量大、圆弧面耐磨性差的问题,项目研制中运用创造性方法学中的“组合”原理,有针对性地选用铝合金和氮化硅陶瓷这两种具有不同性能特点的材料分别作为摇臂基体和工作圆弧面镶块,充分发挥两种材料各自不同的性能优势,从而达到提高产品综合性能,降低制造成本的目的。本文以陶瓷摇臂的批量化生产为目标,针对其关键制造技术进行了深入系统的研究,全文共分为七章,主要内容可概括如下:1.论述了气门摇臂的性能要求,陶瓷材料的性能特点及其在发动机配气机构中的应用,陶瓷材料的加工机理及加工技术,产品的质量控制方法,在此基础上提出论文研究的主要内容和意义。2.针对国内外研究陶瓷摇臂的不足之处,提出了本研究的关键技术:铝合金基体与陶瓷镶块的连接技术;陶瓷镶块的制备和加工技术,铝合金基体的加工技术。并以批量化生产为目标,制定了相应的研究方案。3.为验证陶瓷镶块在压铸时是否会因热应力而破碎,对陶瓷镶块在压铸过程中的温度场和热应力场进行了有限元分析,并与把柄式镶块摇臂进行了对比。4.为了降低陶瓷镶块的加工成本,研制了一种新的加工工艺,即在使用金刚石砂轮对陶瓷镶块进行粗磨和半精磨的基础上,采用普通氧化铝砂轮进行精磨。分析了各种因素,包括磨削用量、材料性能以及切削液等对加工表面粗糙度的影响,最后通过正交试验确定出最佳的磨削工艺。5.首先测量了氧化铝砂轮磨削陶瓷镶块的磨削力,并对磨削表面进行了X光衍射试验和能谱分析。在以上分析的基础上结合表面粗糙度曲线,提出了氧化铝砂轮加工陶瓷获得低表面粗糙度的加工机理和表面形成模型,并分析了各种影响因素的变化引起表面形貌不同的原因。6.运用质量控制的方法对陶瓷镶块的制备工艺(包括陶瓷坯体的成型技术和烧结技术)、铝合金压铸以及摇臂轴孔的精密加工进行了分析,确定最佳的工艺,保证最终的产品质量。7.对所研制的TJ370Q发动机陶瓷摇臂进行了720小时模拟台架试验、300小时全速全负荷可靠性台架试验以及5万公里跑车试验,试验结果证明,与原锻钢摇臂相比,采用本文所开发的陶瓷摇臂后,发动机的耐磨性、可靠性、动力特性、速度特性、启动性能、经济性、排放水平和噪音等均有不同程度的改善。最后,对本文的研究工作和取得的成果进行了总结,并提出了进一步研究的设想。更多还原

【Abstract】 For the sake of solving the problem of great rotary inertia and forged steel rockerarm’s bad wear-resisting property in the engine of Xia Li cars with modelTJ370Q TJ376Q, we utilize the assembly theory of creative engineeringmethodology to respectively make the aluminum alloy materials and siliconnitride engineering ceramics as base stock of rocker arm and cabochon glut. Inthis way, the goodness of these two kinds of materials are fully strengthened. Forthe new rocker arms, their comprehensive property are enhanced and the cost ofmanufacture is lower than before.Aimed at producing rocker arms on a large scale, this paper mainly deals with theresearch of key manufacture technology in the process of production. All of the contentcan be summarized as below:1. This paper discussed property requirement of rocker arms, engineering ceramics’mechanic property and their application in engine’s admission gear, machiningmechanism and techniques of ceramic material and quality control method. Based onall of above discussion, the main content and significance of this paper areproposed.2. In view of existing problem of research on rocker arms, we propose the keytechnique in our research that the techniques of connecting the base stock ofrocker arms with cabochon gluts, the techniques of gluts preparation andmachining and the techniques of machining the aluminum base stock. At thesame time,the research report is worked out with the aim of mass-production.3.To test the probability that the ceramics gluts are broken because of thermalstress during the process of compression casting, the temperature field and thethermal stress field are verified with the method of finite element analysis. Thenthe rocker arms with ceramic gluts are compared with shank type rocker arms.4. To lower the cost of machining, a new process technique is proposed, namely,the ceramic gluts are ground by plain aluminum grinding wheels after theircoarse grinding with diamond grinding wheels. Many factors which could beimpair the quality of ceramics surface such as grinding quantity, material’smechanic property and cooling liquid are analyzed. In this way, the bestprocessing techniques of grinding is determined.5. By testing grinding force, analyzing X-ray diffraction and energy spectrum,and measuring the surface roughness cures, we propose the grinding mechanismand build the grinding models of the grinding process with plain aluminumgrinding wheels.6. The preparation process techniques of ceramics including the techniques ofbody formation and sintering, pressure casting of aluminum alloy and theprecision machining of the rocker arms’ axle holes are analyzed with themethod of quality control to guarantee the quality of production.7. After 720 hours simulating bench test, 300 hours bench test with maximumspeed and maximum load and 50 thousand kilometers running experiments, weconcluded that the TJ370Q engines with ceramic rocker arms are better thanthose with forged steel rocker arms in wear-resisting property, dependability,dynamic property, speed characteristics, initial power property, economicalefficiency, emission level, and noise intensity.Finally, research findings are summarized and the further research presumptionsare proposed.更多还原