摘要
针对现有多轴承支承轴系的刚度计算只限于主轴等对称回转结构,不能分析转动部分结构复杂并且受重力、切削力作用的数控摆台支承轴系的问题.提出一种数控摆台多支承轴系的轴承静刚度计算方法.首先,利用子结构方法对转动部分的有限元模型进行静力凝聚,并通过刚性耦合约束连接缩聚后的有限元模型与支承轴的梁单元模型;其次,结合角接触球轴承的刚度模型建立整个轴系的静力平衡方程,通过迭代求解得到各轴承的实际载荷和刚度.计算了四轴承支承轴系各轴承的载荷和刚度,与商业软件结果的误差小于1%,验证了上述方法的准确性.研究发现:重力作用下摆台支承轴承静刚度随摆角的改变发生显著变化.
At present,the studies of bearings stiffness in multi-bearing system focus on symmetric structures,such as spindle.However,the previous methods are not suitable for the supporting bearings of the CNC（computer numerical control）tilting rotary table which has complex rotary part and suffers gravity force and cutting forces.In this paper,a method was proposed to analyze the bearings static stiffness in the multi-bearing system of the tilting table.The finite element model of the rotary part was condensed with the substructure method and the shafts were represented by beam elements.The beam elements and condensed finite element model were connected by rigid coupling constrain equations.Then the static equivalent equations of the system were achieved with the stiffness model of angular contact ball bearings.And the equations were solved with the iteration algorithm to get the actual loads and stiffness of the bearings.Take a system supported by four bearings for example,the load and stiffness of the bearings were got by the commercial software and the theoretical method respectively.The difference is less than 1% and the method proposed is verified.Finally,it is found that the stiffness of the four bearings of the tilting table vary greatly with the tilting angle when gravity force is considered.
出处
《华中科技大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2015年第10期21-25,共5页
Journal of Huazhong University of Science and Technology(Natural Science Edition)
基金
国家自然科学基金重点资助项目(51235009)
国家科技重大专项资助项目(2011zx04016-031)
关键词
数控摆台
滚动轴承
静刚度
子结构方法
静力缩减
刚性耦合
CNC tilting table
rolling bearing
static stiffness
substructure method
static condensing
rigid coupling
