大模数齿轮近净轧制成形关键技术研究

发布时间：2018-07-08 19:48

本文选题：大模数 + 齿轮　；参考：《北京科技大学》2016年博士论文

【摘要】：齿轮是机械的重要零件之一,其中大模数齿轮广泛应用于重工行业,目前主要以切削加工制造为主,工序多,效率低。齿轮塑性成形工艺可以提高生产效率,保持齿部金属流线连续性,提高齿轮强度及使用寿命。小模数、小直径锥齿轮的精密模锻成形及小模数花键冷轧成形技术已经得到工业应用,但大模数齿轮模数大、直径大,锻造成形载荷大且对模具要求苛刻。因此,本课题提出采用热轧工艺对大模数齿轮近净成形的关键技术进行研究。利用Gleeble-1500D热模拟实验机对SAE8620H齿轮钢高温变形行为进行研究,得到其在高温下的真应力-应变曲线。根据实验结果,建立了其材料本构模型,该模型使用双曲正弦函数,同时考虑了应变对本构方程参数的影响,能够较好描述该齿轮钢热变形下的流动应力-应变关系,为大模数齿轮热轧成形数值模拟提供材料模型数据。通过实验研究了加热温度和保温时间对SAE8620H齿轮钢奥氏体晶粒长大的影响规律,并通过热模拟试验研究了SAE8620H齿轮钢在单向压缩过程中变形温度、应变速率和变形量对奥氏体晶粒细化的影响规律,基于实验数据建立了其微观组织演变模型。提出一种大模数齿轮热轧成形工艺,分析了轧制成形过程中传动齿轮变侧隙啮合对轧辊、转件相对运动关系的影响规律；建立了轧辊、轧件齿形参数间的关系,考虑热胀等因素设计确定了轧辊齿形及坯料尺寸：利用DEFORM软件建立了大模数齿轮热轧成形有限元模型,仿真分析其成形过程,并通过实验获得了大模数齿轮轧件,对比分析了大齿轮热轧过程中轧制力的变化规律。采用有限元方法研究了齿形长起过程中金属流动规律；分析了齿形两端填充不满产生的原因以及工艺参数对齿形两端填充的影响规律,提出凹形坯料设计方法补偿齿形两端填充,通过有限元和实验相结合的方法验证了补偿措施的有效性：分析了轧辊轧件齿廓间相对滑动对齿形拉尖形成的影响,仿真分析了工艺参数对齿形拉尖程度的影响规律,在仿真和实验过程中通过提高成形温度、减小接触摩擦系数并通过轧辊齿根压整作用消除了拉尖现象。研究了大模数齿轮轧件精度影响因素,建立了内孔偏差产生齿距偏差和齿廓形状偏差的数学模型,分析了内孔变化尺寸对齿距偏差和齿廓形状最大偏差的影响规律；建立了轴弯曲变形产生齿廓形状偏差和齿形齿向偏差的数学模型,分析了轧制力和轴直径对齿廓形状最大偏差和齿形齿向偏差的影响规律。通过测量轧件齿形精度得到：轧件单个齿距偏差、齿向偏差、径向跳动偏差达到12级,齿廊形状偏差超出12级精度55.9μm,累积齿距偏差超差较大。对比测量偏差和计算偏差,齿距累积总偏差计算结果和实验结果吻合较好,计算齿廓形状偏差为67.4μm,排除偏差影响因素,齿廊形状精度可以达到12级。调用SAE8620H齿轮钢微观组织演变模型,编写微观组织演变子程序,借助有限元仿真技术分析了热轧大模数齿轮齿部晶粒尺寸分布规律：并研究了轧制温度、进给速度和轧辊转速对热轧大模数齿轮齿部微观组织演变规律的影响：对比实验和仿真轧件观测点晶粒尺寸,晶粒尺寸平均误差11.7%,证明了所建立微观组织模型的可靠性,对工艺实践具有指导意义。
[Abstract]:Gear is one of the most important parts of machinery, of which large modulus gear is widely used in heavy industry. At present, it is mainly based on cutting and manufacturing, with many working procedures and low efficiency. The plastic forming process of gear can improve production efficiency, keep the continuity of metal flow line, improve gear strength and service life. Small modulus, small diameter bevel gear. Dense die forging and small modulus spline cold rolling have been used in industrial application, but large modulus gear has large modulus, large diameter, large forging load and strict requirement to die. Therefore, the key technology of hot rolling process for near net forming of large modulus gear is studied in this paper. The Gleeble-1500D thermal simulation test machine is used for S The high temperature deformation behavior of AE8620H gear steel is studied and its stress-strain curve is obtained at high temperature. According to the experimental results, the constitutive model of the material is established. The model uses the hyperbolic sine function and the influence of the strain on the constitutive equation. It can describe the flow stress and strain under the hot deformation of the gear steel. The effect of heating temperature and holding time on the austenite grain growth of SAE8620H gear steel was studied by experiments. The deformation temperature of SAE8620H gear steel in the unidirectional compression process was studied by thermal simulation test, and the strain rate and deformation amount of austenite should be applied to the austenite. The influence rule of grain refinement is set up based on the experimental data. A hot rolling process of large modulus gear is put forward. The influence law of the gear gear gap meshing on the relative motion relationship of the roll and part in the rolling process is analyzed. The relationship between the roll and the parameters of the gear shape is established, and the heat expansion is considered. The shape of roll tooth and the size of blank are determined by the same factor design: the finite element model of large modulus gear hot rolling is set up by DEFORM software, the forming process is simulated and analyzed, and the large modulus gear piece is obtained by the experiment. The change law of the rolling force in the hot rolling process of the large gear is compared and analyzed. The tooth shape is studied by the finite element method. The law of metal flow in the long process of metal flow; analysis of the causes of the discontent of the teeth at both ends of the tooth and the influence of the process parameters on the filling of the teeth at both ends of the tooth; the concave blank design method is proposed to compensate the filling of the teeth at both ends, and the effectiveness of the compensation measures is verified by the combination of the finite element method and the experimental method: the profile of the roll piece is analyzed. The influence of relative sliding on the formation of tooth profile is simulated. The influence of process parameters on the tooth profile is simulated and analyzed. In the process of simulation and experiment, the drawing temperature is improved, the contact friction coefficient is reduced and the pulling tip is eliminated through the roller tooth root pressing. The influence factors of the precision of the large modulus gear piece are studied, and the influence factors of the precision of the large modulus gear piece are studied. The mathematical model of the deviation of the tooth distance and the profile of the tooth profile is produced by the inner hole deviation. The influence of the size of the inner hole on the deviation of the tooth distance and the maximum profile of the tooth profile is analyzed. The mathematical model of the shape deviation of the tooth profile and the deviation of the tooth profile is established, and the maximum deviation of the tooth profile shape and the diameter of the rolling force and the shaft diameter is analyzed. The influence rule of tooth profile deviation is obtained by measuring the tooth profile accuracy of rolling parts: single tooth distance deviation, tooth direction deviation, radial runout deviation to 12 grade, tooth Gallery shape deviation exceeding 12 grade precision 55.9 mu m, cumulative offset deviation of tooth distance greater. Comparison measurement deviation and calculation deviation, calculation result and experimental result of cumulative total deviation of tooth distance The shape deviation of the tooth profile is 67.4 m, and the shape accuracy of the tooth gallery can reach 12. The microstructure evolution model of the SAE8620H gear steel is called, the microorganization evolution subprogram is compiling, and the grain size distribution law of the number tooth gear part of the hot rolling large mould is analyzed with the aid of the finite element simulation technology. The influence of temperature, feed speed and roll speed on the microstructure evolution of hot rolled large modulus gear teeth: the contrast experiment and the grain size of the simulated workpiece observation point, the average grain size error of 11.7%, proved the reliability of the established microstructure model, and has the guiding significance for the process practice.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TG61;TG335.11

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