载重汽车用直齿圆柱齿轮冷挤压模具强度及寿命研究

发布时间：2018-11-17 21:27

【摘要】：齿轮是汽车与机械领域最常见的传动部件,绝大部分汽车与设备主要传动部件都采用的是齿轮传动,直齿圆柱齿轮是齿轮传动中应用最为广泛的一种齿轮。直齿圆柱齿轮的加工方式目前主要采用传统的切削加工,这不仅耗费工时,材料利用率低,成本也较高。在目前激烈的市场竞争之下,传统的加工方式已无法满足低能耗高质量的要求,而冷挤压加工工艺由于其优质、高效、节能的显著优点,开始广泛地应用于直齿圆柱齿轮的加工中。在齿轮的冷挤压成形过程中,模具承载着较大的单位挤压力,凹模也受到较大的圆周拉应力,即使三层组合凹模,模芯也极易破裂。直齿圆柱齿轮冷挤压模具易破裂的问题严重阻碍了冷挤压技术在齿轮成形中的推广应用。因此,如何避免模具破裂,提高模具强度及寿命是目前研究齿轮冷挤压成形技术的关键。本文以载重汽车用轮边减速器直齿圆柱齿轮为研究对象,提出连续挤压的冷挤压工艺方案,并采用传统经验计算的组合凹模进行冷挤压成形数值模拟分析;基于均匀过盈量组合凹模的失效分析,提出变过盈量的设计方法,通过对该方法的研究,进一步提出了组合凹模局部变过盈量设计方法,并对该方法进行了深入的研究;采用响应面法对组合凹模尺寸参数进行优化设计,确立了合理的组合凹模尺寸参数,充分的发挥了材料的性能;针对齿轮金属流动规律及模具应力分布规律进行分析,研究了各工艺参数对齿轮成形质量、模具应力及模具温度的影响规律。根据有限元数值模拟结果,进行了直齿圆柱齿轮的冷挤压工艺试验及生产应用,试验结果表明:冷挤压加工的直齿圆柱齿轮成形质量较好;模具挤压次数达15万件后,模具使用情况良好,挤压件公法线检测长度在设计要求范围之内;变过盈量组合凹模的设计方法及组合凹模结构参数的优化设计可以提高模具的使用寿命。试验结果验证了数值模拟的准确性。
[Abstract]:Gear is the most common transmission part in the field of automobile and machinery. Most of the main transmission parts of automobile and equipment are gear transmission. Spur gear is the most widely used gear in gear transmission. At present, the machining method of spur gear mainly adopts traditional cutting, which not only consumes man-hours, but also has low material utilization ratio and high cost. In the current fierce market competition, the traditional processing methods can no longer meet the requirements of low energy consumption and high quality, while the cold extrusion process has the remarkable advantages of high quality, high efficiency and energy saving. It has been widely used in the machining of spur gear. In the cold extrusion forming process of gears, the die bears a large unit extrusion pressure, and the die is subjected to larger circumferential tensile stress. Even if the three layers combined die, the die core is easy to break. The problem that the cold extrusion die of spur gear is easy to rupture seriously hinders the popularization and application of cold extrusion technology in gear forming. Therefore, how to avoid the die rupture and improve the die strength and life is the key to the research of gear cold extrusion forming technology. In this paper, the straight cylindrical gear of wheel side reducer used in truck is taken as the research object, and the cold extrusion technology scheme of continuous extrusion is put forward, and the numerical simulation analysis of cold extrusion forming is carried out by the combination die of traditional experience calculation. Based on the failure analysis of combined die with uniform interference, the design method of variable interference is put forward. Through the research of this method, the design method of local variable interference of combined die is put forward, and the method is studied deeply. The response surface method is used to optimize the dimension parameters of the combined die, and the reasonable dimension parameters of the combined die are established to give full play to the performance of the material. Based on the analysis of metal flow law of gear and stress distribution of die, the influence of various technological parameters on gear forming quality, die stress and die temperature is studied. According to the results of finite element numerical simulation, the cold extrusion technology test and production application of spur cylindrical gear are carried out. The results show that the forming quality of straight tooth cylindrical gear processed by cold extrusion is good. When the extrusion times of the die reach 150000, the working condition of the die is good, and the inspection length of the common line of the extruded parts is within the range of the design requirement. The design method of the combined die with variable interference and the optimum design of the structural parameters of the combined die can improve the service life of the die. The experimental results verify the accuracy of the numerical simulation.
【学位授予单位】：重庆理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U466;TG375.41

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