【作者】 张利芹；

【导师】 张小龙；

【作者基本信息】 西安建筑科技大学 ， 机械设计及理论， 2006， 硕士

【摘要】 滚动轴承作为一种重要的机械基础部件,广泛应用于机械工程的各个领域。随着计算机技术和非线性动力学理论的发展,特别是旋转机械的高速化发展,过去滚动轴承按刚性支承处理的思路过分简化了转子系统的动力学问题,往往不能得到足够准确的解答。滚动轴承支承的高速转子系统的动力特性在很大程度上取决于其轴承的特性,尤其是轴承的径向非线性刚性特性。为了保证滚动轴承支承的转子系统稳定安全运转,有必要研究滚动轴承非线性刚性对系统分岔、混沌等动力特性的影响。本文的研究对象是深沟球轴承支承的水平刚性转子系统,分析滚动轴承在不同径向间隙时转子的非线性动力学行为,对转子系统进行数值计算,模拟转子系统复杂的非线性现象。 取球轴承的径向内部间隙为主要研究参数,分析了平衡和不平衡这两种转子系统的动力学响应特性。计算结果表明,系统在某些参数域中可能发生倍周期分岔、拟周期和混沌运动,用数值积分方法得到系统在某些特殊参数域中的分岔图、轴心轨迹图、相图和Poincaré图。 对于平衡转子系统,转子的运动形态在很大程度上取决于滚动轴承的径向内部间隙。随着间隙的增大,不稳定区和混沌响应区变宽,同时位移响应的峰值增大即轴承的动态刚度减小。 不平衡转子系统的非线性是由于赫兹接触和轴承的径向间隙引起的,系统的激励频率为振动频率和转子的旋转频率。数值计算结果表明,当轴承—转子系统的转速变化时,动态响应出现了失稳现象。 本文通过数值计算和对计算结果的分析,为滚动轴承—转子系统在设计方面提供理论基础。更多还原

【Abstract】 Being as an important cadre, the ball bearing is widely used in every field of mechanical engineering. With the development of computer science and nonlinear dynamics, especially the quick tempo of revolver, the thought that ball bearing’s stiffness is linear excessively predigested problems in rotor dynamics, which frequently can not find enough exact answers. Dynamic behaviors of a rotor with high speed supported by ball bearings is greatly determined by the characteristics of the bearing, especially its nonlinear radial stiffness. For the sake of stability and security of a rotor, it is necessary to study the effects of a ball bearing’s nonlinear stiffness on system’s dynamic behaviors. The main object of this thesis is to study a horizontal rigid rotor supported by deep groove ball bearings, analyze the nonlinear dynamics of rotor system in case of different internal clearances, calculate the rotor system and simulate its complex nonlinear dynamic behaviors.The radial internal clearance of a deep groove ball bearing is taken as the main parameter, the effect of which on the dynamics response of the two kinds of rotor system (balanced or unbalanced) is studied. The results of a parametric study have resulted in the observation that the systems may undergo period doubling bifurcation, quasi-periodic and chaotic motions. In some typical parameter regions the bifurcation diagrams, the shaft centerline orbit, the phase portrait, the Poincaré maps are acquired by numerical integration methods.For the balanced rotor system, radial internal clearance is an important parameter for determining the dynamics response. It is seen that with increase in clearance the region of unstable and chaotic response becomes wider, meanwhile the peak value of displacement response becomes greater.For the unbalanced rotor system, the nonlinearity is both due to Hertzian contact and the radial internal clearance of bearing. The system is excited by the varying compliance frequency and the rotational frequency. The results have shown the appearance of instability in the dynamics response of the system as the speed of the bearing-rotor system is changed.Through analysis of calculating results, some important conclusions are obtained, which may be useful for engineering applications.更多还原