Calculation Method of Radial Runout of Machine Tool Spindle Based on Bearing Grinding and Matching Clearance

Abstract

The invention provides a calculation method for the radial runout of a machine tool spindle on the basis of bearing grinding and matching clearances. The method aims at achieving the time-varying performance of the radial runout of the machine tool spindle in a bearing dynamic wear process and improving the authenticity of the radial runout of the front end of the spindle. The method includes theimplementing steps that on the basis of a Hertz point contact theory, contact analysis of a front bearing and a rear bearing of the spindle are performed respectively; the time-varying wear of the front bearing and the time-varying wear of the rear bearing are calculated; the radial internal clearance after the front bearing of the spindle is installed and the radial internal clearance after the rear bearing is installed are calculated; the time-varying displacement amount of a gyration center of the spindle under the front bearing grinding and matching clearance and the time-varying displacement amount of the gyration center of the spindle under the rear bearing grinding and matching clearance are calculated; the time-varying radial runout of the front end of the spindle is calculated. The method can be used for performance analysis and optimization design of a spindle system.

Description

technical field [0001] The invention belongs to the field of mechanical engineering, and relates to a method for calculating the radial runout of a machine tool spindle. The method considers the time-varying wear process of the machine tool spindle bearing, calculates the time-varying radial runout of the front end of the spindle during the dynamic wear process of the bearing, and can be used for Performance analysis and optimal design of machine tool spindle system. technical background [0002] As a crucial subsystem in CNC equipment, the CNC machine tool spindle system is used to install tools or workpieces. It is a key component for equipment to achieve machining. Whether its accuracy and performance are good will greatly affect the machining accuracy and life of the equipment. As the most important key functional part in the spindle system, bearings can be mainly divided into two categories: sliding bearings and rolling bearings. Rolling bearings are widely used due to ...

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Problems solved by technology

[0004] Judging from the current public information, the radial runout of the spindle is mainly obtained through three methods. One is to monitor the radial runout of the machine tool through a radial runout detection device. This method requires a certain test environment, and It is difficult to detect the radial runout value of the working process of the machine tool in real time; the second is to obtain the radial runout of the front end of the spindle through finite element simulation. Modal analysis obtains the critical speed of the main shaft, and then uses harmonic response analysis to obtain the radial runout of the front end of the main shaft, but this method cannot reflect the degradation process of the main shaft radial runout during the working process of the main shaft

The last method is to calculate the radial runout of the front end of the spindle through the bearing clearance. In the existing technology of this method, only the radial runout of the front end of the spindle under a certain clearance can be calculated, and real-time calculation of the radial runout of the front end of the spindle is impossible. For example, in his master thesis "Digital Modeling and Analysis Method of Machine Tool Spindle Rotation Accuracy", Wei Kun of Chongqing University of Technology disclosed a calculation method for calculating the radial runout of the spindle considering the bearing clearance. (0.01mm) changing the radius value of the outer ring of the front and rear bearings, combined with the established geometric error model of the spindle system rotation accuracy, the influence of the change of the front and rear bearing clearances on the radial runout of the spindle front end was analyzed. In the runout calculation, the calculation is not based on the real clearance change of the bearing, so the final calculation result can only explain the relationship between the radial runout at the front end of the spindle and the bearing clearance, and cannot reflect the real time-varying radial runout at the front end of the spindle

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