Research On The Mechanism Of Online And Reverse Calculation Of The Unbalancing Vector Of Thin Disk Workpiece

Thin disk parts are common parts in rotary mechanism.Because of the large rotation radius of the thin disk part,the huge unbalancing vector may be formed even if the unbalancing mass is small.Therefore,it is necessary to check and correct the unbalance of thin disk parts before assembly.At present,the dynamic balancing machine is often used to detect and calibrate the unbalancing vector of thin plate workpieces in the production field,which has the problems of high balancing cost,low balancing efficiency and balancing accuracy.Based on the structural characteristics and balance requirements of thin disk workpieces,This paper proposes a method to estimate the unbalancing vector of the workpiece indirectly by analyzing the unbalancing vibration difference of the spindle before and after the workpiece is clamped on the spindle of CNC machine tool without striking the workpiece,and the key problems of this method are systematically studied.The main research contents are as follows:(1)The integrated dynamic modeling of workpiece spindle is studied.Taking the spindle system of CNC machine tool as the prototype,the dynamic model of thin disk workpiece –spindle-bearing system is established,and the influence of workpiece unbalance on spindle system unbalance is discussed by simulation method.(2)Aiming at the problem of unbalanced vibration signal extraction,EMD and least square method are used to extract the unbalanced vibration of spindle system.The feasibility of this method is discussed by theory with simulation.(3)Considering that the accuracy of the influence coefficient may be influenced by the change of the spindle system kinetic characteristic parameters,the signal measurement and analysis errors,etc.The adaptive method for influence coefficient is proposed.The convergence of the method is discussed by theory and simulation.(4)Taking the basic structure of spindle system structure of CNC machine tool as the prototype,the mechanism system for dynamic balance experiment of the spindle and workpiece is designed and manufactured,and the vibration signal acquisition and analysis system is developed.(5)Based on the experimental system,a large number of experimental studies have been carried out on the key issues such as the acquisition and extraction of the initial unbalanced vibration signal of the spindle system,the acquisition and extraction of the workpiece spindle coupling unbalanced vibration signal,the calculation of the influence coefficient,the reverse measurement of workpiece unbalancing vector and adaptation of influence coefficient,etc.,which systematically verifies the feasibility of the theory and method proposed in this paper.In this paper,the mechanism and technology of online reverse measurement of the unbalancing vector of thin disk workpiece are systematically studied.The proposed on-line measurement method of workpiece unbalancing vector can be used to monitor the unbalancing vector in the process of workpiece processing.It is significant to improve the machining accuracy of thin disk workpieces,save the cost of workpiece balancing,and improve the efficiency and accuracy of workpiece balancing.