重卡后桥减速器用圆锥滚子轴承大挡边结构优化

发布时间：2018-09-16 21:27

【摘要】：重型卡车后桥减速器是重卡传动系的一部分,减速器所用圆锥滚子轴承是保证其正常运行的关键零部件之一。某重型卡车后桥减速器选用32013型圆锥滚子轴承,由于轴承须在重载、承受大冲击载荷并承受径向和轴向载荷的恶劣工况下运行,大挡边会偶发轴向断裂的现象,这将降低轴承使用的可靠性和寿命。所以,需要对轴承大挡边断裂现象进行分析,找出断裂原因和解决措施,确保轴承安全、可靠的运转。本文主要的研究内容包括以下方面:(1)研究了圆锥滚子轴承32013大挡边断裂失效的原因。分析了圆锥滚子轴承32013的结构,确定了单个轴承的受力状态。根据实际工况下重型卡车后桥减速器轴承受载形式及相关参数,计算出了轴承所受载荷的大小。计算结果表明,发生断裂失效现象的轴承是在超载的工况下运行的,所以超载是导致轴承断裂失效的根本原因。(2)研究了提高大挡边强度的方法。通过对影响轴承大挡边强度因素的分析,提出了增大大挡边厚度来减小挡边所受应力的方法,分别利用传统力学和有限元软件计算出了挡边厚度加厚时对应的应力值。结果表明,增大挡边厚度,可提高挡边强度。随后,研究了大档边加厚的轴承结构。基于轴承设计轻量化的设计准则,确定了大挡边加厚的尺寸方向,依据标准32013结构图,对滚子长度和大径做了相应调整,得出了挡边加厚后的轴承内圈结构图。(3)应用有限元分析了轴承大挡边的受力状况。通过ANSYS软件分别对额定载荷和超载时轴承模型所受载荷的仿真分析,计算了不同载荷时大挡边处的接触应力,发现轴承超载时所受应力及变形程度均高于额定载荷时的状态。通过对不同挡边厚度模型的有限元分析,发现随着挡边厚度的不断增加,大挡边处所受应力将逐渐减小的变化趋势,进而印证了增大挡边厚度可以降低挡边所受应力的可行性。接着,依据大挡边的结构形式和大挡边受力作用点对挡边强度的影响,确定了优化后的大挡边尺寸并推导出了挡边受力作用点位置的计算公式及挡边与内滚道夹角的取值范围,得到了优化后的大挡边结构尺寸。(4)验证了大挡边优化后的圆锥滚子轴承32013的疲劳寿命。依据优化后的轴承结构尺寸图,对轴承制定了合理的生产加工工艺与检测要求,应用疲劳寿命实验机机对优化后的轴承做疲劳实验,发现当挡边厚度为a=5.49±0.01,ψ=89°27'~89°38'时,轴承不再出现断裂失效现象,此时轴承寿命可完全满足使用要求。
[Abstract]:The rear axle reducer of heavy truck is a part of the heavy truck transmission system. The tapered roller bearing used in the reducer is one of the key parts to ensure its normal operation. The rear axle reducer of a heavy truck uses 32013 type tapered roller bearing. Because the bearing has to operate under the bad conditions of heavy load, heavy impact load and radial and axial load, the large flange will occasionally break in the axial direction. This will reduce the reliability and service life of bearings. Therefore, it is necessary to analyze the fracture phenomenon of bearing big flange, to find out the cause of fracture and to solve the problem, to ensure the safe and reliable operation of bearing. The main contents of this paper are as follows: (1) the causes of fracture failure of tapered roller bearing 32013 big flange are studied. The structure of tapered roller bearing 32013 is analyzed and the stress state of single bearing is determined. According to the bearing load form and related parameters of rear axle reducer of heavy truck under actual working condition, the load magnitude of bearing is calculated. The calculation results show that the bearing with fracture failure is operated under the condition of overload, so overload is the fundamental reason for the failure of bearing fracture. (2) the method to improve the strength of large flange is studied. Based on the analysis of the factors affecting the strength of the large flange of the bearing, the method of increasing the thickness of the flange to reduce the stress on the flange is put forward. The stress values corresponding to the thickening of the flange are calculated by using the traditional mechanics and finite element software respectively. The results show that the strength of the flange can be improved by increasing the thickness of the flange. Then, the bearing structure with thickened edge is studied. Based on the lightweight design criterion of bearing design, the dimension direction of thickening of large flange is determined. According to the standard 32013 structure diagram, the length and diameter of roller are adjusted accordingly. The structure diagram of bearing inner ring with thickened flange is obtained. (3) finite element analysis is used to analyze the force condition of bearing big flange. Through the simulation analysis of the load on the bearing model under rated load and overload by ANSYS software, the contact stress at the big flange under different loads is calculated. It is found that the stress and deformation degree of the bearing under overload is higher than that at rated load. Through the finite element analysis of different flange thickness models, it is found that with the increasing of the thickness of the flange, the stress at the big flange will gradually decrease, which proves the feasibility that increasing the thickness of the flange can reduce the stress of the flange. Then, according to the structural form of large flange and the effect of force acting point on the strength of flange, the optimized size of large flange is determined, and the formula for calculating the position of acting point and the range of angle between flange and inner raceway are deduced. The optimized size of the large flange structure is obtained. (4) the fatigue life of the optimized tapered roller bearing 32013 is verified. According to the structural size diagram of the optimized bearing, the reasonable production and processing technology and the testing requirements were made for the bearing. The fatigue test was carried out on the optimized bearing by using the fatigue life tester. It was found that when the thickness of the flange was 5.49 卤0.01, 蠄 89 掳270.89 掳38', Bearing no longer appears fracture failure phenomenon, this time the bearing life can fully meet the requirements.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U463.218

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