螺栓联接和支撑结构对大型转盘轴承寿命影响的基础研究

The large-scale slewing bearing is the key rotary connection of large equipment, such as TBM and wind turbine. The working ability and reliability of these equipments are determined by the slewing bearing's load capacity and life which are greatly influenced by its bolt connection and supporting structure. At present, the bolt connection and supporting structure are segregated to study their effects on the load performance of slewing bearing because there is no effective analysis model. The combined effect of bolt connection and supporting structure on the load performance of slewing bearing is unknown. At the same time, the design of slewing bearing is multipurpose. The load capacity and life may be not enough in specific application. In this project, the minimum element of the slewing bearing system is studied at first. The numerical models of single bolt, bolt group connection are developed. The stiffnees of bolt group is obtained. The stiffness of supporting structure and bearing rings is gotten by super-element. The mechanics model of the slewing bearing system is developed by connecting these element stiffness, which is the basis of the bearing life analysis and optimal design. The influences of the bolt stiffness and the supporting structure stiffness on the bearing life are studied. Then, the criterion for choosing bolt connection or supporting structure to optimal design is constituted. With the optimization objective of maximum bearing life. The optimal design methods of bolt connection and supporting structure are studied. The objective of this project is to improve the load distribution and life of slewing bearing by active stiffness design of the bolt connection and supporting structure. The new method is offered for the design of slewing bearing by this study.

大型转盘轴承是盾构机、风力发电机等大型装备的关键联接转动件，受低刚度螺栓联接和支撑结构影响的转盘轴承承载性能和寿命决定了此类大型装备的工作能力和使用可靠性。由于缺乏有效的分析模型，现有研究通常独立分析螺栓联接或支撑结构对转盘轴承力学性能的影响，二者的联合作用尚不明确。同时，转盘轴承的设计具有一定的通用性，特定应用时轴承承载性能和寿命或不足。本项目从转盘轴承螺栓联接的最小单元着手，研究单个螺栓、螺栓组联接的数学建模和刚度矩阵表达，研究支撑结构和轴承套圈弹性模型和刚度矩阵表达。将单元刚度串联为系统刚度建立转盘轴承-螺栓-支撑结构系统的力学模型，奠定快速分析基础。研究螺栓联接和支撑结构刚度对转盘轴承承载性能和寿命的影响，以轴承寿命最大为目标，研究转盘轴承螺栓联接和支撑结构的优化策略和相应设计方法，通过螺栓联接和支撑结构的主动刚度优化，提高转盘轴承寿命。项目研究为转盘轴承的设计应用提供一种新方法。

转盘轴承及其支撑结构具有尺寸大、壁厚薄的特点，且轴承与支撑结构常采用螺栓联接，造成转盘轴承滚动体-滚道接触载荷和疲劳寿命容易受支撑结构刚度和螺栓预紧力的影响。项目研究的宗旨是主动控制转盘轴承支撑结构刚度和螺栓预紧力，以期提高转盘轴承的承载能力和疲劳寿命。项目首先从提取支撑结构刚度矩阵方法研究着手，耦合支撑结构刚度矩阵，建立了转盘轴承-螺栓-支撑结构的系统力学模型。同时建立了转盘轴承轴承-螺栓-支撑结构的整体有限元模型，分析计算了轴承支撑结构刚度、螺栓数量和螺栓预紧力等参数对转盘轴承内部接触载荷分布和疲劳寿命的影响。研究表明螺栓数量约为滚动体数一半时，轴承承载能力最高。验证了前述转盘轴承-螺栓-支撑结构刚度矩阵及系统力学模型，提出了转盘轴承螺栓联接和支撑结构的优化原则。基于前述研究，以轴承内部载荷均匀化和轴承寿命最大为目标，针对小型转盘轴承，进行了转盘轴承螺栓联接参数优化和支撑结构拓扑优化研究，并且获得了螺栓非均匀预紧的最佳预紧力以及最优支撑结构的拓扑结构。提出了一种创新的滚动轴承滚动体与滚道接触载荷的间接测量方法，该方法的基本思想为测量滚动体-滚道接触表面下方的接触变形，反算滚动体-滚道接触力。采用该方法，建立了小型转盘轴承力学性能的测试实验台，实现了轴承内部接触载荷的测量。实测了转盘轴承内部接触载荷分布，验证了转盘轴承螺栓联接的参数优化方法和拓扑结构优化的有效性。