Research On The Optimization Of The Grinding Process Based On The Improvement Of The Precision Retention Of The Ball Screw Pair

Precision retention is an important performance indicator of of ball screws.Compared with foreign products,there is a large gap which seriously restricts the development of domestic high-grade machine tools and the improvement of modern manufacture.Therefore,this paper studies the grinding technology to improve the precision retention of ball screws,which provides theoretical and experimental basis for improving the precision retention of ball screws,and has great significance for improving the quality of ball screws.The precision decline model of ball screws was first studied.According to the contact characteristics between balls and raceways and the mechanism of friction and wear,the model of friction moment and precision decline of ball screws was established,the experiment of precision retention was carried out,the precision decline model was analyzed,and then the model of friction moment decline and precision decline of ball screw pairs were revised,which reduces the theoretical prediction error from 40%-50% to 10%.The grinding technology of ball screw was then studied.The relationship between the friction moment of measurable parameters and the normal pressure was analyzed,and an on-line monitoring method of normal pressure was put forward.Orthogonal test method and single factor test method were used to study the effects of abrasive particle size,grinding moment,ratio of grinding fluid and types of abrasive particles on travel variation,surface roughness and residual compressive stress,and the optimum parameters for ball screw grinding were pointed out.The validity of grinding process for improving precision retention was last verified.The comparative experiment of accuracy retention was carried out by using the acceleration method.Combining with the measurement and analysis results of the travel variation,friction moment,surface roughness and residual stress of the ball screws,the effect of the grinding process on the ball screws was comprehensively evaluated: The residual compressive stress of the raceway increases by 1-2 times,the raceway surface roughness Ra keeps a small value,and can effectively improve the travel variation of the ball screws,thereby slowing down the decline speed of the precision of the ball screw and improving the precision retention.