直伞齿轮滚轧成形工艺的数值模拟研究

发布时间：2018-01-27 10:17

本文关键词： 锥齿轮滚轧成形突耳缺陷多道次数值模拟　出处：《吉林大学》2016年硕士论文　论文类型：学位论文

【摘要】：齿轮是一种很重要的回转类传动零件,实现近距离轴之间动力的传动,具有安装结构紧凑、动力传递过程安全可靠、服役寿命长、传动效率高、噪音小、传动比精确且可变范围大等优点,在机械传动领域得到普遍的应用。随着机械行业的不断发展,对齿轮质量的要求不断提高,消除齿轮缺陷,提高齿轮质量成为齿轮塑性加工的重要发展方向之一。锥齿轮滚轧成形过程中产生突耳缺陷,成形结束后在齿顶区形成折叠缺陷,导致锥齿轮无法使用,找出突耳缺陷的产生原因,设计出消除突耳缺陷的滚轧成形方法十分必要。目前有关锥齿轮滚轧成形中突耳缺陷消除方法的研究报道尚未查到,为了消除锥齿轮滚轧过程中出现的突耳缺陷,获得齿形无缺陷的锥齿轮,本文对直齿锥齿轮滚轧成形工艺进行了研究,通过UG建立齿轮模型,使用有限元分析软件DEFORM对锥齿轮滚轧成形工艺进行数值模拟。分析了锥齿轮滚轧过程中齿形左右两侧突耳的形成过程,提出了突耳缺陷的形成机理。研究了摩擦剪切因子、滚轧轮进给速度、滚轧轮转速和滚轧轮齿顶圆角对突耳缺陷形成的影响规律,并根据突耳的形成机理,设计出了能够消除突耳缺陷的锥齿轮多道次滚轧成形工艺,得出主要研究结果如下:1.锥齿轮滚轧成形过程中,坯体与滚轧轮轮齿的接触区不断改变,坯体右侧齿廓受到由坯体齿根向齿顶方向的变形力,坯体左侧齿廓受到由坯体齿顶向齿根方向的变形力。坯体变形过程中,齿形左右两侧齿廓表层金属流动趋势大于内部,形变差的存在导致了突耳缺陷的形成。坯体齿形右侧齿廓金属流动层厚度大于左侧齿廓,是右侧突耳高度大于左侧突耳高度的主要原因。2.摩擦剪切因子增加,右侧突耳高度增大,最大增加值为0.51mm,左侧突耳高度无明显变化规律;滚轧轮进给速度增加,右侧突耳高度增大,最大增加值为0.48mm,左侧突耳高度减小,最大减小值为0.25mm;滚轧轮转速增加,右侧突耳高度减小,最大减小值为0.48mm,左侧突耳高度增加,最大增加值为0.26mm;滚轧轮齿顶圆角半径变化时,左右两侧突耳高度均没有明显变化规律。3.基于突耳缺陷的形成机理,提出了先进给、后旋转的锥齿轮多道次滚轧成形工艺,并通过曲线标定法确定每道次滚轧轮的预进给量,第一道次至第四道次分别为2.1mm、3.6mm、5.2mm和6.9mm。多道次滚轧成形时,坯体齿形两侧金属流动趋势大于内部,多道次滚轧轮的齿根有效的抑制了金属不均匀变形,限制了突耳缺陷的形成。多道次滚轧轮的预进给量过小时,突耳缺陷得不到有效抑制;预进给量过大时,齿形金属溢出在坯体齿根处形成折叠缺陷。
[Abstract]:Gear is a kind of very important rotary transmission parts. It has compact installation structure, safe and reliable power transfer process, long service life, high transmission efficiency and low noise. With the development of mechanical industry, the requirement of gear quality has been improved, and the defect of gear has been eliminated because of the advantages of accurate transmission ratio and wide variable range, and it has been widely used in the field of mechanical transmission. Improving gear quality has become one of the important development directions of gear plastic machining. Bevel gear has ear breaking defect in rolling forming process and folding defect in the top of tooth after forming, which leads to bevel gear can not be used. It is necessary to find out the causes of ear defects and to design a rolling forming method to eliminate them. At present, the research on the methods of eliminating ear defects in bevel gear rolling has not been reported. In order to eliminate the defect of bevel gear in rolling process and obtain the bevel gear with no tooth shape, the forming process of straight bevel gear is studied in this paper, and the gear model is established by UG. The forming process of bevel gear rolling was simulated by finite element analysis software DEFORM. The influence of friction shear factor, feed speed of rolling wheel, rotational speed of rolling wheel and round angle of tooth top of rolling wheel on the formation of ear burst defect was studied. The multi-pass rolling forming process of bevel gear is designed to eliminate the defect of bevel gear. The main results are as follows: 1. During the rolling forming process of bevel gear, the contact zone between the billet and the gear tooth changes continuously. The tooth profile on the right side of the billet is deformed from the root of the billet to the top of the tooth, and the tooth profile on the left side of the billet is deformed from the top of the tooth to the root of the tooth. The surface metal flow trend of the tooth profile on the left and right sides is larger than that of the inner surface, and the deformation difference leads to the formation of the defect of the ear protruding. The thickness of the metal flowing layer on the right side of the tooth profile of the billet is greater than that on the left tooth profile. The main reason is that the height of the right ear is higher than that of the left ear. The friction shear factor increases and the height of the right ear increases with the maximum value of 0.51mm. the height of the left ear does not change obviously. The feeding speed of the rolling wheel increased, the height of the right ear increased, the maximum added value was 0.48 mm, the height of the left ear decreased and the maximum decrease value was 0.25 mm. The rotational speed of the rolling wheel increased, the height of the right ear decreased, the maximum decrease was 0.48 mm, and the height of the left ear increased, the maximum value was 0.26 mm. When the radius of the top corner of the gear is changed, there is no obvious change in the height of the right and left ear. 3. Based on the forming mechanism of the ear bursting defect, the multi-pass rolling forming process of the bevel gear is put forward, which is advanced and rotated. The pre-feed rate of each pass rolling wheel is determined by curve calibration method. The first to 4th passes are 2.1 mm / 3.6 mm / 5.2 mm and 6.9 mm / m respectively. The metal flow trend on both sides of the billet tooth profile is larger than that on the inside, and the tooth root of the multi-pass rolling wheel can effectively restrain the non-uniform deformation of the metal and limit the formation of the ear-piercing defect. The pre-feed rate of the multi-pass rolling wheel is too small. Ear defects can not be effectively inhibited; When the prefeed rate is too large, the tooth shape metal overflow forms folding defect at the tooth root of the billet.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TG61;TG335

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