转台轴承静刚度建模及其影响因素分析

Static Stiffness of Three-Row Cylindrical Roller Bearing for Rotary Table

为了改善转台的动静特性,分析了三排圆柱滚子转台轴承静刚度与轴承结构型式、装配工艺和外载荷的关系。结合轴承游隙、螺钉拧紧力矩、径向与轴向滚子间的相互作用和外载荷等因素,将轴向滚子与轴圈间的接触看作理想平面接触,考虑径向滚子压力沿轴向的分布,并利用Boussinesq力与变形关系式求解实际的压力值,通过求解轴承的整体静力平衡方程,得到了三排圆柱滚子转台轴承5个方向的静刚度值。分析结果表明:转台固有频率测试与理论值误差不超过3.0%,验证了刚度理论模型的准确性;轴向滚子与径向滚子载荷间的相互作用很小;螺钉拧紧力矩、径向游隙和外载荷对转台轴承刚度有重要影响,随着螺钉拧紧力矩和径向预压量的增大,外载荷对刚度的影响减弱。

To improve static and dynamic performances of rotary table, the effects of configurations, assembling technology and external load on the static stiffness of a three-row cylindrical roller bearing for rotary table are investigated. A theoretical model of static stiffness of three-row cylindrical bearing for rotary table is proposed considering the clearance, bolt preloads, and reactions of axial and radial rollers with external load. The contacts between the axial rollers and the outer ring are treated as ideal plane contact. And the actual contact forces and their distribution along the axial of radial rollers are obtained by Boussinesq＇ s relationship between force and deformation, the static stiffness in five directions is then sought out by solving the static equivalent equations. It is shown that the maximum error between experimental and theoretical results of natural frequency of the rotary table is less than 3.0%, thus the theoretical model is verified. The reactions between loads acting on the axial rollers and radial rollers are negligible. The bolt preloads, radial clearance and external load exert obvious effects on the static stiffness of rotary table bearing, and the effect preloads of bolts and radial clearance. of external load decreases with the increasing preloads of bolts and radial clearance.