Research On Friction Characteristics Of Gun Drill Spindle Bearings

For decades,with the rapid development of Chinese economy,the hole processing industry has also developed rapidly.In the hole processing industry,deep hole processing occupies a major position.A very important tool in the field of deep hole processing is the gun drill.At present,there is a gun drill spindle whose spindle bearing only can be used about 2months.As a result,the gun drill spindle has to be replaced.Thus,increasing the service life of the spindle bearing is necessary.Through the analysis of the damaged bearing,the preliminary judgment is that the raceway and the cage are worn and damaged.Therefore,it is necessary to analyze the relevant friction characteristics.The result can provide reference for the subsequent optimization of the bearing design and the improvement of the service life of the bearing.In this paper,after considering the contact,collision and lubrication effects of various parts in the bearing,the dynamic analysis model of rolling bearing is established based on the relevant theories of rolling bearing dynamics.By using ADAMS,a parametric model of the rolling bearing was established and the corresponding parametric modeling interface was created.The FORTRAN was used to write subroutines for calculating the interaction between the parts of the bearing.The user subroutines are connected with ADAMS,and the dynamic simulation model of the rolling bearing was established.Rolling bearing used in the gun drill spindle is used as an example,the influence law of bearing speed,axial load,clearance ratio,inner and outer raceway groove radius coefficients on the friction torque related to the bearing raceway and cage are analyzed.The analysis results show that:(1)Under the premise that other conditions remain unchanged,the frictional moment between the roller and the inner raceway of the bearing is greater than the frictional moment between the roller and the outer raceway of the bearing.(2)The increase in speed or axial load will increase the friction torque between the roller and the inner and outer raceways,and also increase the average collision friction torque between the cage and the outer ring of the bearing.(3)As the bearing clearance ratio increases,the friction torque between the roller and the bearing raceway first decreases and then increases,and the average collision friction torque between the cage and the outer ring of the bearing increases.(4)With the increase of the coefficient of curvature radius of the inner/outer raceway,the friction torque between the inner/outer raceway of the rolling is gradually reduced,and the frictional torque between the outer/inner raceway does not change significantly;the cage and the bearing outer The average collision friction torque between the rings gradually increases.(5)Through orthogonal experiment and queuing scoring method,the optimal structural parameters of the bearing are obtained: the inner raceway groove radius coefficients is 0.53,the outer raceway groove radius coefficients is 0.54,and the clearance ratios is 0.7.