多场耦合条件下中空轴式重载静压轴承设计理论与方法

Working at low speed in the heavy-duty and harsh environment, hydrostatic bearing is one of the key components of the large mill. With the size of the mill machine become larger, hydrostatic bearing must work under larger pressure, and also, more higher standard about its reliability, life span, maintainability and energy consumption are requested by users. To master the design philosophy and the key technology of the large, heavy-duty hydrostatic bearing, this project establish the nonlinear multi-body dynamics model by combining the discrete element simulation analysis method and the multi-body dynamics algorithm. Start and brake cases are simulated by using these two mathematic model above, and also, the dynamic load of bear at the two work cases are predicted. These numeric simulation results provide the accurate boundary condition to the further fluid-structure-thermo coupling analysis. The corresponding experimental results obtained on the scale mill machine, which designed using the theory of similarity, are compared with the numeric solution elaborately. Many factors, such as the bearings angle, the angle, width and the deviation angle of the oil chamber, the fit clearance, the stiffness of the cylinder, cover and the hollow shaft, the stiffness and the lubricating oil viscosity of the bearing lining body, all of which have the sensitive effect against the oil film's bearing capacity, are studied respectively. The method about how to determine the hydraulic system parameters of the hydrostatic bearing is proposed in this project. Optimal design method about the structural parameters of both the bearing bracket and the bearing lining body is given. Finally, the design theory and the simulation methods of the exclusive used heavy-duty hydrostatic bearing are obtained, and this can significant improve our independent designed capacity of the hydrostatic bearing serviced in the heavy-duty large mill machines.

静压轴承是大型磨机的核心部件，其在重载、低速恶劣环境下工作；随着球磨机规格的不断增大，对其承载能力、可靠性、使用寿命、维护及能耗提出了更高的要求，为攻克承受重载、尺度巨大的静压轴承设计理论难题与关键技术，本项目采用球磨机筒体内多体运动的离散元仿真分析与多体动力学计算相结合，建立磨机起动/制动工况的非线性多体动力学模型，预测对应工况下轴承所受动载荷，为静压轴承提供准确的边界条件进行流/固/热耦合分析，与采用相似理论设计的比例磨机进行试验研究对比分析，提出轴瓦包角、油腔包角、油腔宽度、油腔偏位角、配合间隙、筒体和端盖的刚度、中空轴的刚度、轴承衬体的刚度和润滑油粘度对油膜承载能力的影响规律；提出静压轴承液压系统参数的确定方法；结合轴承座与轴承衬体的接触非线性分析，提出轴承座和轴承衬体结构参数的优化设计方法；形成大型磨机专用重载静压轴承的设计理论与方法，提升我国大型球磨机静压轴承的自主设计。

中空轴式重载静压轴承是大型磨机的核心部件，随着磨机规格的不断增大，对在重载恶劣环境中的静压轴承的承载能力、可靠性、使用寿命、维护周期及能耗提出了更高的要求。针对我国磨机行业所设计的静压轴承，运行可靠性差，运行能耗和使用维护成本较高的问题，提出了一套轴承承载能力最大和功率消耗最小的静压轴承优化设计方法。.（1）建立了多场耦合分析模型，模拟了油膜和轴承、中空轴间的相互作用力及其变形协调规律，研究了供油压力和流量随设计参数调整而产生的变化量，并采用相似理论搭建了缩比磨机，按正交实验法确定了试验方案进行验证，研究了油腔形状、油腔包角、油腔偏位角和油腔宽等因素对轴承承载能力和功率消耗的影响。.（2）提出了基于离散元仿真的轴承载荷谱计算方法，为中空轴式静压轴承的流固热耦合分析提供了边界条件。结合非线性动力学、离散元方法，建立了包含有矿石的离散元模型，获得了磨机全工作过程的动态载荷谱。利用比例磨机全工作过程动态载荷谱测试，验证了离散元分析结果的准确性。.（3）建立了重载静压轴承和回转体的分析模型，研究了整机和轴承关键参数对优化目标的影响规律，提出了轴承承载能力最大和功率消耗最小的静压轴承优化设计方法。以轴承承载能力最大和轴承消耗功率最小为优化目标，以整机性能和油膜完整性的保障性技术参数（包角、油腔位置、油腔数量和大小等）为约束条件，建立了一个多目标优化模型，采用拉丁超立方方法确定了实验方案，应用粒子群算法和遗传算法获得了静压轴承最佳的设计参数。. 本项目形成了大型磨机重载静压轴承的设计理论与方法，突破了大型球磨机重载静压轴承设计的关键技术。能够提升我国大型球磨机静压轴承自主设计能力，制造出具有我国自主知识产权的磨矿高效、运行可靠、降耗节能的大型磨机，提高我国大型球磨机的国际竞争力。