短时高过载下滚动轴承承载与破坏的研究

发布时间：2018-01-22 15:36

本文关键词： 滚动轴承载荷分布弹塑性变形油膜厚度 ANSYS APDL　出处：《南京理工大学》2011年硕士论文　论文类型：学位论文

【摘要】：在飞行器传动机构中,滚动轴承需满足短时工作、高过载、正反运转、有限寿命(不超过几个小时)、高可靠性、无润滑运行等要求。在这种短时高过载工况下,滚动轴承的设计还必须满足传动机构体积小、重量轻的要求。普通轴承在设计计算中均以弹性理论公式为基准,针对长寿命工况分析计算。对于高周疲劳,轴承内部由于接触引起的塑性变形与弹性变形相比很微小；但在短时高过载工况下塑性变形不能忽略,较大塑性变形使轴承在短时间内有被破坏的危险。在选用现有商品化滚动轴承时,需要进行特殊设计,目前还没有形成通用的设计理论。本文针对短时高过载工况,以滚针轴承和角接触球轴承为研究对象,分析滚动轴承在这种特殊工况下的过载能力,旨在为实际工程中的设计应用提供一些理论依据。本文考虑塑性变形,基于Palmgren半经验公式推导了高过载滚动轴承的载荷分布,并分析了游隙、制造精度、过盈装配等因素对载荷分布的影响。计算结果表明,角接触球轴承的轴向载荷对工作接触角影响明显,而径向载荷影响很小；游隙对滚针轴承载荷分布的影响很大,适当过盈可提高承载力,但滚针最大负荷增大。本文同时分析了过载或冲击载荷作用下滚动轴承的滚动体最大负荷、滚压安定及导致钢球或滚针卡死不转的载荷。润滑状态对轴承的寿命影响重大,本文基于弹流润滑理论,分析了滚动轴承在高过载工况下的最小油膜厚度和中央油膜厚度。计算结果表明滚针轴承润滑条件很差,难以形成油膜；而球轴承在接触表面平均粗糙度小于0.1μm时,即使是接触塑性变形达到钢球直径万分之十,仍可以形成润滑油膜。在计算机仿真方面,分析了有限元法求解点接触和线接触问题的仿真误差,使用ANSYS APDL语言建立了滚动轴承的六面体单元有限元模型。在前面分析的基础上,提出高过载滚动轴承的破坏形式,并将计算方法尝试用于柔性轴承强度校核。
[Abstract]:In the transmission mechanism of the aircraft, the rolling bearing should meet the requirements of short time operation, high overload, positive and negative operation, limited life (no more than a few hours, high reliability). The design of rolling bearing must meet the requirements of small volume and light weight of transmission mechanism under this short time and high overload condition. In the design and calculation of ordinary bearing, the elastic theory formula is the basis. For high cycle fatigue, the plastic deformation caused by contact is very small compared with elastic deformation. But the plastic deformation can not be ignored under the short term high overload condition, the larger plastic deformation causes the bearing to be destroyed in a short time. When selecting the existing commercial rolling bearing, special design is needed. At present, no general design theory has been formed. In this paper, the overload capacity of roller bearing and angular contact ball bearing under this special working condition is analyzed in view of the short time high overload condition and taking the needle roller bearing and angular contact ball bearing as the research object. The purpose is to provide some theoretical basis for the design and application of practical engineering. In this paper, considering plastic deformation, the load distribution of high overload rolling bearing is deduced based on Palmgren semi-empirical formula, and the clearance and manufacturing accuracy are analyzed. The calculation results show that the axial load of angular contact ball bearing has a significant effect on the working contact angle, but the radial load has little effect on the working contact angle. The influence of clearance on the load distribution of needle roller bearing is very great. Proper interference can increase the bearing capacity, but the maximum load of needle is increased. This paper also analyzes the maximum rolling load of rolling bearing under overload or impact load. The rolling stability and the load that leads to the steel ball or the needle clamping does not turn. The lubrication state has a great influence on the bearing life, this paper is based on the elastohydrodynamic lubrication theory. The minimum oil film thickness and central oil film thickness of rolling bearing under high overload condition are analyzed. The results show that the lubrication conditions of needle roller bearing are very poor and it is difficult to form oil film. When the average roughness of ball bearing is less than 0. 1 渭 m, even if the contact plastic deformation reaches 10/10000, lubricating oil film can still be formed. The simulation error of solving point contact and line contact problem by finite element method is analyzed. The hexahedron element finite element model of rolling bearing is established by using ANSYS APDL language. The failure form of high overload rolling bearing is put forward, and the calculation method is attempted to be used to check the strength of flexible bearing.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH133.33

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