柴油机气门座圈压装试验研究及CAE分析

发布时间：2018-06-27 16:04

本文选题：气门座圈 + 常温压装　；参考：《重庆大学》2016年硕士论文

【摘要】：气门座圈作为发动机缸盖上的一个重要零件,它与气门头部配合对气缸起密封作用,用于控制新鲜空气的吸入与废气的排除,其性能影响发动机的油耗、功率、效率乃至寿命。气门座圈的工作环境十分恶劣,除了承受高温燃气的腐蚀外,还要承受气缸内爆发压力及气门的高速冲击。因此,气门座圈压装工艺作为缸盖装配中重要的工艺过程,其压装质量将直接影响发动机的工作性能、输出功率及使用寿命。本文首先介绍了气门座圈压装的国内外现状,阐述了柴油机气门座圈的结构特点、工作原理及压装工艺。然后针对实际生产中某特定型号的柴油机气门座圈凡尔线跳动和真空试漏超差问题进行了分析,通过一系列对比试验最终确定了根本原因,并针对实际情况提出了具体改进及解决措施,成功解决了工厂实际问题。为了进一步提高座圈压装效率和降低成本,提出了可以用常温压装工艺代替冷冻压装工艺的改进方法,通过与冷冻压装试验对比分析验证了常温压装的可行性,并提出了用座圈周向应变及力-位移曲线作为判断常温压装可靠性的标准。阐述了过盈配合理论及有限元分析理论基础,依据厚壁圆筒理论推导出的组合厚壁圆筒公式对气门座圈过盈配合的数学模型进行了理论计算,得到了气门座圈过盈配合时的弹性力学解,并对其过盈配合强度进行了校核。最后,介绍了过盈装配非线性接触问题的求解方法及过盈量在ANSYS接触中的正确设置方法,根据理论分析对气门座圈压装过程进行了有限元仿真,分析得到了压装过程中零件的应力、应变等情况,并通过ANSYS参数化编程得到了压装过程中的力-位移(F-S)曲线。本文针对柴油机气门座圈的压装这一课题,通过试验研究成功解决了工厂实际问题,并对压装工艺提出了改进。在理论分析的基础上利用有限元方法对过盈配合进行了仿真分析,仿真分析结果与理论分析结果具有较好的一致性,充分说明了有限元仿真分析的可行性,其结果可以为气门座圈设计、压装工艺优化、压装设备选择及过盈量的选择等提供参考依据。
[Abstract]:As an important part of the engine cylinder head, the valve seat ring plays a sealing role with the valve head to control the intake of fresh air and the removal of exhaust gas. Its performance affects the fuel consumption, power, efficiency and even life of the engine. The working environment of the valve seat ring is very bad. Besides the corrosion of the high temperature gas, it also has to withstand the burst pressure in the cylinder and the high speed impact of the valve. Therefore, as an important process in cylinder head assembly, the pressing quality of valve seat ring will directly affect the working performance, output power and service life of engine. This paper first introduces the present situation of valve seat ring pressing at home and abroad, and expounds the structure characteristics, working principle and pressing technology of the valve seat ring of diesel engine. Then, the paper analyzes the runout of valve seat ring and vacuum test leakage excess difference of a certain type of diesel engine in actual production, and finally determines the fundamental reason through a series of comparative tests. According to the actual situation, the concrete improvement and solving measures are put forward, and the practical problems of the factory are solved successfully. In order to further improve the efficiency and reduce the cost, an improved method which can replace the frozen pressing process with the normal temperature pressing process is put forward, and the feasibility of the normal temperature pressure packing is verified by comparing it with the frozen pressure loading test. The circumferential strain and the force-displacement curve of the pedestal ring are used as the criteria to judge the reliability of the pressure loading at room temperature. The theory of interference fit and the theoretical basis of finite element analysis are expounded. The mathematical model of the interference fit of valve seat ring is calculated theoretically according to the combined thick wall cylinder formula derived from the theory of thick wall cylinder. The elastic mechanical solution of the interference fit of valve seat ring is obtained, and the strength of interference fit is checked. Finally, the solution method of nonlinear contact problem of interference assembly and the correct setting method of interference quantity in ANSYS contact are introduced, and the finite element simulation of valve seat ring pressing process is carried out according to the theoretical analysis. The stress and strain of the parts in the process of pressing are analyzed, and the force displacement (F-S) curves are obtained by ANSYS parameterized programming. In this paper, the practical problems of the diesel engine valve seat ring are solved successfully through experimental research, and the improvement of the pressing process is put forward. On the basis of theoretical analysis, the interference fit is simulated by using finite element method. The simulation results are in good agreement with the theoretical analysis results, which fully shows the feasibility of finite element simulation analysis. The results can provide a reference for the design of valve seat ring, the optimization of pressing process, the selection of pressing equipment and the selection of interference.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK423

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