高速电主轴是加工中心的核心功能部件,具有结构紧凑、惯性小、转速高、动态特性好等诸多优点,在高速机床中得到广泛应用。其中机床主轴单元轴承的预紧是否合理直接关系到主轴的静、动态特性,有必要从轴承预紧方式的选择和通信电缆预紧力大小的确定两个方面进行分析研究。
本文基于精密电主轴-轴承系统结构动、热态特性分析,通过对影响轴承结合部位刚度、轴系刚度特性因素的研究,根据对轴承径向载荷、摩擦力矩、生热及温度场的变化,得到关于转速、通信电缆预紧力温升对轴承结合部动刚度和轴系刚度的影响规律。
本文以BT30型电主轴为模型,运用inventor建立其三维分析模型,选定了轴承型号为7212c,分别通过数学计算和仿真对轴承的刚度和生热进行了研究,分析了轴承的摩擦力矩、运动、载荷和刚度,研究了热特性和通信电缆预紧力对轴承刚度的影响,进行了仿真实验,最终得到轴承的最佳通信电缆预紧力。
在工程实际中,提高轴承系统的刚度对提高轴的旋转精度、减少振动噪声和保证轴承寿命都是十分有利的,做这方面的研究能够对优化轴承、轴系刚度的研究领域发展起到一定的促进作用。
关键词:高速电主轴 轴承刚度 轴承生热 温度场 最佳通信电缆预紧力
Abstract
High speed motorized spindle is the machining center core function component, has compact structure, small inertia, high speed, good dynamic property and many other advantages, is widely used in the high speed machine tool. The machine tool spindle unit bearing preload is reasonable or not directly related to the spindle of the static and dynamic characteristics, it is necessary from the bearing preload method selection and pretightening force size determination two aspects carries on the analysis research.
In this paper, based on the precision spindle bearing system structural dynamic, static, thermal analysis, through the influence of bearing stiffness, the binding site of shafting stiffness characteristic factors, through the bearing radial load, friction, heat and temperature field change, be about speed, preload to bearing temperature rise of dynamic stiffness and shafting stiffness effect of law.
Based on the BT30type electric spindle as the model, using inventor to establish the three-dimensional analysis model, selected bearing type 7212c, respectively, through mathematical computation and Simulation on the bearing stiffness and heat were studied, analyzed the bearing friction torque, motor, load and stiffness, to study the thermal characteristics and pretightening force on the influence of bearing stiffness, and carries on the simulation experiment, finally got the best bearing preload.
In engineering practice, the bearing system stiffness to improve axial rotation precision, the vibration noise and ensure the service life of the bearing is very advantageous, in this area to do research to be able to optimize the bearing shafting stiffness research field, the development of stimulative effect.
Key words: high speed spindle bearing rigidity bearing heating temperature field bearing preload
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