The Research On NC Grinding Technology For Small Pitch Thread Of Planetary Screw Pair

In space field,in order to meet the requirements of large load,high reliability and small working space of the spaceflight electromechanical servo mechanism,the requirements of the screw actuator,which is the executive part of the electromechanical servo mechanism,have also been put forward with high load,high reliability and compact structure.Therefore,we has developed the standard planetary roller screw pair.In the follow-up production of the screw pair,it is necessary to use NC grinding machine to grind the small pitch thread,for meet the requirement of thread precision,it is necessary to study the NC grinding process for the small pitch thread,and determine the wheel dressing scheme and the NC grinding program of the thread.The NC grinding of small pitch thread can be realized to meet the design requirement.In this background,this dissertation studies the NC grinding of the small pitch screw threads in the standard type planetary roller screw pair,and realizes the precision NC grinding of the small pitch thread,grasp the technology of CNC grinding small pitch thread,and guide the production of planetary roller screw pair.The research work of this dissertation is as follows.(1)The principle of helicoid grinding is summarized,according it to deduce the contact line condition of grinding wheel.Grasp the design process of the grinding wheel truncation,calculate the grinding wheel truncation used in the grinding of the small pitch thread of the planetary roller screw,and guide the dressing of the wheel.(2)Based on the structure requirements of the small pitch screw thread of the planetary roller screw,design the plan of dressing wheel,Develop the dressing test for CBN grinding wheel and optimizing the dressing parameters of CBN wheel,and analysis the effect of grinding wheel dressing parameters on thread grinding.(3)According to the structural characteristics of the thread in the planetary roller screw pair,determine the NC grinding scheme for the small pitch thread.The NC grinding process test of small pitch thread is carried out,and the optimization grinding parameters are obtained,the analysis the effect of the grinding parameters on the surface quality of thread grinding and the angle of threaded teeth.(4)Build the calculation model of measure the single pitch diameter of the roller arc profile by the three needle measurement,and use the two thread parameters to calculate the influence of the thread parameters on the selection of the pin's optimum diameter.The feasibility of using three needle method to measure single pitch diameter of small pitch circular arc thread is dmeonstrated,it provides a theoretical basis for rapid measurement of single thread diameter in production.