锡青铜连杆衬套错距旋压关键工艺参数对成形质量的分析及其优化

发布时间：2018-01-18 13:25

本文关键词：锡青铜连杆衬套错距旋压关键工艺参数对成形质量的分析及其优化　出处：《中北大学》2017年硕士论文　论文类型：学位论文

【摘要】：连杆衬套是连接发动机连杆小端与活塞销的关键零部件,在发动机工作过程中,连杆衬套不仅受到与其配合的连杆小端及活塞销的摩擦作用,同时高温环境及交变应力的影响也对其性能提出了很高的要求。连杆衬套一般采用错距旋压成形工艺制造,作为一种先进的表面塑性强化成形工艺,采用错距旋压强化后的连杆衬套,疲劳强度、承载能力等性能均能达到工作要求。主要存在的问题是经错距旋压成形后工件的内径精度不够理想,必须保证足够的加工余量以完成后续的精车工序。有时会因为工艺参数设置不合理等原因,导致工件口部扩径严重以致内径尺寸无法满足后续精车余量的要求,造成人力物力资源的浪费。同时由于形状误差的存在,后续精车工序中工件表面各处的切削深度各不相同,其表面硬度、金相组织、残余应力等存在较大的差异,导致产品使用可靠性大大降低。本文采用数值模拟方法建立了锡青铜连杆衬套错距旋压有限元仿真模型,并通过实验验证了该模型的可靠性。在此基础上,采用单因素试验设计方法研究了减薄率、进给比、首轮压下比、轴向错距、主轴转速对错距旋压成形过程中三旋轮径向旋压力、轴向旋压力、切向旋压力、径向力均方差及旋压成形后工件内径精度、圆度误差、直线度误差的影响规律。根据单因素试验分析结果及实际生产情况,确定了以进给比、首轮压下比、轴向错距为试验因素,以三旋轮径向力均方差、工件内径公差、外表面圆度误差为优化指标的正交试验设计方案,对正交试验方案中各因素水平组合进行仿真计算,并获得了各试验组合下三旋轮径向力均方差、工件内径公差、外表面圆度误差的数值。最后基于正交试验设计的直观分析和综合平衡法对试验结果进行分析,得到了最优的工艺参数组合。
[Abstract]:The connecting rod bushing is the key component to connect the small end of the connecting rod with the piston pin. In the working process of the engine, the connecting rod bushing is not only affected by the friction between the small end of the connecting rod and the piston pin. At the same time the influence of high temperature environment and alternating stress also put forward very high requirements for its performance. The connecting rod bushing is generally manufactured by staggered spinning forming process as an advanced surface plastic strengthening forming process. The performance of connecting rod bushing strengthened by staggered spinning, fatigue strength and bearing capacity can meet the working requirements. The main problem is that the inner diameter precision of the workpiece formed by staggered spinning is not ideal. It is necessary to ensure sufficient machining allowance to complete the subsequent finishing process. Sometimes, due to unreasonable setting of process parameters, the diameter of the workpiece mouth is so serious that the dimension of the inner diameter can not meet the requirements of the spare capacity of the subsequent finishing car. At the same time, due to the existence of shape error, the cutting depth of various parts of the workpiece surface in the subsequent finishing process is different, its surface hardness, metallographic organization. There are great differences in residual stress and so on, which results in a great decrease in the reliability of the product. In this paper, the finite element simulation model of the dislocation distance of the tin bronze connecting rod bushing is established by numerical simulation method. The reliability of the model is verified by experiments. On the basis of this, the thinning rate, feed ratio, first wheel pressure ratio and axial offset are studied by single factor experimental design method. In the process of spin-forming, the radial rotation pressure, axial rotation pressure, tangential rotation pressure, radial force mean square deviation, the precision of inner diameter and roundness of the workpiece after spinning. According to the single factor test results and actual production conditions, the feed ratio, the first wheel pressure ratio, the axial offset are determined as the test factors, and the radial force mean square deviation of the three rotating wheels is taken as the test factor. The design scheme of orthogonal test with the tolerance of inner diameter of workpiece and roundness error of outer surface as the optimization index is simulated and calculated for the horizontal combination of various factors in the orthogonal test scheme. The values of radial force mean square deviation, inner diameter tolerance of workpiece and roundness error of outer surface are obtained. Finally, the test results are analyzed based on the intuitive analysis of orthogonal test design and the comprehensive balance method. The optimal combination of process parameters is obtained.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG306

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