薄壁四点接触球轴承刚柔耦合多体动力学分析

发布时间：2018-05-25 07:51

本文选题：薄壁四点接触球轴承 + 四点接触　；参考：《昆明理工大学》2017年硕士论文

【摘要】：工业机器人在汽车制造、机械加工及航天航空等领域得到广泛应用。腕部关节动力学特性对工业机器人的平稳性、定位精度以及可靠性等关键的动态性能指标有重要的影响。薄壁四点接触球轴承作为工业机器人的关键配套专用轴承,目前对此类轴承的研究仅停留在静力学阶段,无法满足工业机器人配套轴承的研究需求。变速变加速工况下考虑特殊冠型结构保持架的中大型尺寸薄壁四点接触球轴承的动力学特性是工业机器人动力学研究的难点,还处于尝试探索阶段。运用多体动力学方法和有限元方法,考虑轴承特殊冠型结构保持架和中大尺寸薄壁套圈的弹性变形,各部件之间复杂动态接触关系,建立工业机器人用薄壁四点接触球承和腕部关节的刚柔耦合动力学模型。深入分析了薄壁四点接触球轴承和腕部关节的动力学性能和保持架的稳定性以及弹性变形影响等重要问题,为国内此类轴承高性能自主研发提供理论支持。论文的主要研究工作如下:(1)基于Hertz接触理论基础,对薄壁四点接触球轴承的接触应力和接触变形进行理论推导计算,得到点接触问题的基本方程以及载荷分布规律,运用有限元方法建立单滚动体和整个轴承的多体接触静力学模型,讨论网格划分和接触参数的选择对结果计算的影响,分析在不同径向载荷下的四点接触和变形量及载荷分布规律,与Hertz理论计算值对比验证仿真结果的有效性。(2)基于多体动力学方法,利用ADAMS软件建立薄壁四点接触球轴承多刚体动力学分析模型,计算得到薄壁四点接触球轴承特有的运动形式、接触规律及其他动力学特性,分析了不同转速和预紧力等工况下薄壁四点接触球轴承的动力学性能,获得四点接触特性和变化规律。(3)考虑中大型尺寸薄壁套圈和特殊冠型保持架的弹性变形,基于ADAMS/Flex模块和有限元模态分析,建立内外套圈和冠型保持架的柔性体模型。考虑钢球和柔性套圈的四点动态接触关系,建立薄壁四点接触球轴承的刚柔耦合多体接触动力学模型。对比分析了多刚体和刚柔耦合条件下球轴承的动态接触特性,表明弹性变形和动态四点接触作用对中大型尺寸薄壁球轴承的动态接触力的大小和振动位移有不可忽视的影响。(4)建立由腕关节基座,两套薄壁四点接触球轴承和两个空心轴构成的多体接触动力学分析模型,在静力学条件下计算了整个空心轴、套圈和基座的变形结果;对基座及空心轴进行柔性化后,对其整个腕部刚柔耦合多体接触动力学系统进行动力学分析,模拟不同载荷比和正反转变速俯仰运动等变速工况下,薄壁四点接触球轴承的动力学性能及其对腕部关键系统的影响。
[Abstract]:Industrial robots are widely used in automobile manufacturing, mechanical processing, aerospace and other fields. The dynamic characteristics of wrist joint play an important role in the stability, positioning accuracy and reliability of industrial robot. Thin-walled four-point contact ball bearings are the key matching special bearings for industrial robots. At present, the research on such bearings is only in the statics stage, which can not meet the research needs of industrial robot matching bearings. The dynamic characteristics of large and medium size thin wall four-point contact ball bearings with special crown type cages under variable speed and variable acceleration conditions are difficult points in the dynamic research of industrial robots and are still in the stage of exploration. By using the multi-body dynamics method and the finite element method, the elastic deformation of the bearing special crown cage and the middle and large size thin-walled ring are considered, and the complex dynamic contact relationship between the components is considered. A rigid-flexible coupling dynamic model of thin-walled four-point contact ball bearing and wrist joint for industrial robot is established. The dynamic properties of thin wall four-point contact ball bearings and wrist joints, the stability of cage and the influence of elastic deformation are deeply analyzed, which provides theoretical support for the independent research and development of such bearings with high performance in China. The main research work of this paper is as follows: (1) based on Hertz contact theory, the contact stress and contact deformation of thin wall four-point contact ball bearing are deduced and calculated, and the basic equation of point contact problem and the law of load distribution are obtained. The finite element method is used to establish the multi-body contact statics model of the single rolling body and the whole bearing. The influence of mesh generation and contact parameter selection on the calculation results is discussed. The four-point contact and deformation and load distribution under different radial loads are analyzed. The validity of the simulation results is verified by comparing with the calculated values of Hertz theory. The dynamic analysis model of multi-rigid body of thin-walled four-point contact ball bearing is established by using ADAMS software. The special motion form, contact law and other dynamic characteristics of thin-walled four-point contact ball bearing are calculated. The dynamic properties of thin-walled four-point contact ball bearings under different rotating speed and preloading conditions are analyzed. The four-point contact characteristics and variation law of four-point contact ball bearings are obtained. The elastic deformation of thin-walled rings and special crown cages with medium and large size is considered. Based on ADAMS/Flex module and finite element modal analysis, the flexible body model of inner and outer ring and crown cage is established. Considering the four-point dynamic contact relationship between steel ball and flexible ring, a rigid-flexible coupling multi-body contact dynamic model of thin-walled four-point contact ball bearing is established. The dynamic contact characteristics of ball bearings under multi-rigid and rigid-flexible coupling conditions are compared and analyzed. It shows that elastic deformation and dynamic four-point contact action have important influence on the dynamic contact force and vibration displacement of large-sized thin-walled ball bearings. Two sets of thin-walled four-point contact ball bearings and two hollow shafts are used to analyze the multi-body contact dynamics. The deformation results of the whole hollow shaft, ring and pedestal are calculated under static conditions, and the base and hollow shaft are flexible. The dynamic analysis of the whole wrist rigid-flexible coupling multi-body contact dynamic system is carried out, and the variable speed working conditions such as different load ratio and positive and inverse rotation pitch motion are simulated. The dynamic performance of thin-walled four-point contact ball bearing and its influence on the key system of wrist.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP242.2;TH133.3

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