汽车空心齿轮轴毛坯精密成形及工艺优化

发布时间：2018-06-17 02:26

  本文选题：空心齿轮轴 + 旋锻　； 参考：《重庆理工大学》2017年硕士论文

【摘要】：汽车齿轮轴是汽车传动系中传递扭矩的一个重要零件。在相同的横截面积、材料的情况下,空心轴比实心轴承受的外力矩大。若将实心齿轮轴换成空心齿轮轴,可达到减轻汽车自重,从而提高汽车的环保性和节能性、降低燃油消耗和减少排放。基于以上目的,本课题以Forge2011软件对空心齿轮轴进行数值模拟和正交试验法优化旋转锻造成形工艺参数,并对旋锻件进行了物理验证和等温正火处理工艺参数研究。研究情况如下:(1)根据合作方提供的某型号产品零件结构图和体积不变原理,对空心齿轮轴的旋锻成形坯料和成形特点进行分析,通过UG软件建立了空心齿轮轴坯料、锤头和芯棒组成的三维模型,并导入Forge2011软件进行旋锻成形相关参数设置和多道次文件编写。(2)主要分析了锻件转速、锤头压下量等各参数变量对空心齿轮轴温旋锻成形的折叠缺陷、有效应变、锤头载荷、温度梯度的影响。结果表明:锻件转速和锤头压下量的变化对空心齿轮轴成形的折叠缺陷影响较大;随着轴向相对送进量的增加,锤头载荷有相对减弱的趋势,而随着锤头径向压下量的增大,锤头载荷先急剧增大后缓慢增加;轴向相对送进量和径向速度对坯料温度梯度影响较显著,随轴向相对送进量的增加,第一工序后坯料的最高温度、最低温度和第二工序处初始温度随之增高,随着锤头径向速度的增加,它们先减小后增大;轴向相对送进量和径向压下量对空心齿轮轴成形的螺旋脊椎纹缺陷影响较大,随着锻件轴向相对送进量的增大,表面台阶变化越来越急,表面甚至出现了螺旋脊椎纹,最大有效应变值先变大后变小,随着压下量的增加,最大有效应变值逐渐增大,螺旋脊椎纹逐渐明显;随着坯料初始温度和锻件转速的增大,最大有效应变值先逐渐增大后变小,变化急剧程度不一致,有效应变分布震幅情况也是先逐渐集中后辐射;随着锤头径向速度的增大,最大有效应变值先变小后变大,且变形程度变化不均匀。(3)根据正交试验法模拟分析获得较优参数组为:坯料的初始温度为830℃,轴向相对送进量为0.05mm,坯料每次转角为23°,锤头径向压下量为2mm,锤头径向速度7.5mm/s。物理实验结果分析为:从微观组织分析可知,旋锻成形使晶粒细化、获得纤维组织和提高致密性;显微硬度变化表明了不均匀性变形和晶粒致密性的提高。(4)根据对试制件不同等温正火工艺处理研究,获得较优参数为两次连续不同等温正火工艺,工艺流程为:第一次等温正火,加热炉930℃保温180min,5Hz空气冷却至580℃,恒温炉内580℃保温150min,空气冷却至室温;第二次等温正火,加热炉930℃保温180min;0Hz风冷到580℃;等温炉580℃保温150min;空冷至室温。显微组织分析得:横向和纵向是均匀分布的铁素体-珠光体组织,晶粒度和带状组织达到厂家要求。
[Abstract]:Automobile gear shaft is an important part of transmission torque in automobile transmission system. In the case of the same cross-sectional area and material, the external torque of the hollow shaft is greater than that of the solid shaft. If the solid gear shaft is replaced by the hollow gear shaft, the weight of the vehicle can be reduced, the environmental protection and energy saving of the vehicle can be improved, and the fuel consumption and emissions can be reduced. Based on the above purpose, the numerical simulation and orthogonal test of hollow gear shaft were carried out by Forge2011 software, and the technological parameters of rotary forging were optimized, and the physical verification and isothermal normalizing process parameters of rotary forging were carried out. The research results are as follows: 1) according to the structure diagram and volume invariant principle of a certain type of product provided by the partner, the forging blank and forming characteristics of hollow gear shaft are analyzed, and the hollow gear shaft blank is established by UG software. The 3D model composed of hammer head and mandrel is introduced into Forge2011 software to set the relevant parameters of forging forming and to write multi-pass file. (2) the rotational speed of forgings is mainly analyzed. The influence of various parameter variables such as hammerhead reduction on the folding defect, effective strain, hammer load and temperature gradient of the hollow gear shaft in warm rotary forging. The results show that the changes of forging speed and hammerhead reduction have a great influence on the folding defect of hollow gear shafts, and with the increase of axial relative feed amount, the hammer load tends to weaken relatively, but with the increase of the radial reduction of the hammer, The axial relative feed rate and radial velocity have a significant effect on the temperature gradient of the blank. With the increase of the axial relative feed rate, the maximum temperature of the blank after the first working procedure increases. The minimum temperature and initial temperature in the second working procedure increased, and with the increase of the radial velocity of the hammer, they first decreased and then increased, and the axial relative feed and radial reduction had a great influence on the helical spine defects formed by the hollow gear shaft. With the increase of the axial relative feed, the surface step changes more and more rapidly, and even the spiral spine appears on the surface. The maximum effective strain value first increases and then becomes smaller, and with the increase of the reduction, the maximum effective strain value increases gradually. With the increase of the initial temperature of the billet and the rotational speed of the forgings, the maximum effective strain value first increases gradually and then becomes smaller, the change degree is not consistent, and the earthquake amplitude of the effective strain distribution is gradually concentrated first and then radiated. With the increase of radial velocity of hammer head, the maximum effective strain value first decreases and then becomes larger, and the deformation degree varies inhomogeneously. 3) according to the orthogonal test method, the optimum parameters are obtained as follows: the initial temperature of the blank is 830 鈩，

本文编号：2029202