Analysis Of The Imbalance Vibration Behavior Of High Speed Spindle And Research Of Its Suppression Method

High speed machining technology is an advanced manufacturing technology in contemporary, widely used in machining aerospace, automobile manufacturing industry, instrument manufacturing industry, optical and precision manufacturing industries and other processing areas. Important features of High speed machining technology are high efficiency, high precision, high surface quality and other manufacturing characteristics. High speed machine tools are the main equipment and the key factor to achieve High speed machining technology. Since motorized spindle has been a core functional parts of High speed machine tools,its structure and dynamic performance directly affects the efficiency of High speed machining and the manufacturing precision of key parts. Analysis of the behavior of spindle space vibration and research on the suppression method are of great significance to the application of high speed machining technology in our country.This thesis launches the research on the High speed motorized spindle, then a "rotor-bearing- disc" coupling dynamic model of the spindle structure is established using finite element method, and the unbalance vibration behavior of the spindle has been made in-depth analysis and discussion. For heavy shortcomings that the current rotor balancing technology needs to startup several times to add or remove trial weights, a balancing method without trial weights is proposed based on the finite element dynamic model of the High speed spindle.Firstly, in this thesis,the finite element dynamic model for the angular contact ball bearing has been made on the Jones model considering the centrifugal and gyroscopic effect of the rolling element, and the bearing stiffness matrix is obtained, since the highly nonlinear equations that consist of rolling element geometric constraint equations and force balance equations is solved with the method of combining linear search with the improved Newton-Raphson iteration algorithm. Change curves are given that related parameters of rollers and bearings with the spindle speed, axial force and radial force acted on the bearing.Secondly,the bearing is regarded as a bearing unit of 2 nodes that its outer ring is being fixed on the spindle box, and inner ring rotating along with the spindle, in addition to torsional degrees of freedom, each node contains five degrees of freedom; Finite element dynamics model of spindle rotor, pull rod, spindle box and other beam structure are made using Timoshenko beam element of 2 nodes considering shearing action; Using disc unit considering the eccentric quality, dynamics modeling of encoder, counterweight plate and other plate structure is modeling are made; Finally the finite element dynamic model of spindle system is obtained by integrating each rotor, disc, bearing module on the basis of the bearing stiffness.Then the finite element dynamic model about one existing High speed spindle is made, and simulation analysis is presented from the modal, harmonic response, vibration response in time domain separately. The results of modal analysis and harmonic response analysis are compared with ANSYS. Finally, a modal experimental of High speed spindle is carried on. Conclusion joint of analysis results of ANSYS and the experiments verify the validity and accuracy of finite element dynamics model of spindle system.Finally, based on the unbalance vibration analysis of finite element dynamic model of the High speed spindle, finally paper proposes a method without trial weights. Experiments show that this method can effectively reduce the amount of residual unbalance rotor vibration, and has broad application prospects in the rotor dynamic balance.