Research On Surface Coverage Of Inner Race Of Industrial Robot Bearing Based On Intensified Grinding

Coverage is an important factor affecting the effect of intensive grinding,but the interpretation and research of coverage is the least in the whole field of intensive grinding.In fact,the surface coverage is an important parameter for strengthening grinding.At present,there are few researches based on the three aspects of strengthening grinding,bearing and coverage.There is less research on the relationship between the coverage rate and the processing technology,the relationship between the coverage rate and the bearing surface performance,and which level of coverage rate should be selected to achieve the best intensified grinding effect.In this paper,the inner ring of the thin-walled deep groove ball bearing（601910） is taken as the research object,and the method of measuring the bearing surface coverage based on the intensive grinding is proposed.The calculation formula of the coverage rate of intensive grinding was established.ABAQUS is used to simulate the diameter of the micro pit.After getting the diameter of the micro pit,the random function of MATLAB is used to generate the graph,and the coverage is calculated.The influence rules of the injection angle and the diameter of the steel ball on the coverage of the bearing are obtained.It is proposed to use Halcon software to calculate the bearing coverage and operation flow.The effects of injection angle,ball diameter and workpiece speed on the bearing surface coverage are verified by experiments,and the relationship between the inner ring of bearing with different coverage and microhardness is studied.The phase,dislocation density and residual stress of bearing inner ring with different coverage were analyzed by XRD.（1）Under the same processing conditions,the coverage will increase with the diameter of the steel ball.The time required for 1.0mm steel ball to reach 100% coverage is twice the time required for 2.0mm steel ball.Under the same condition of other processing conditions,with the increase of workpiece speed,the coverage will become low.The time required for the workpiece speed to reach 100%coverage is about 1.3 times of the time required for the workpiece speed to reach 100%coverage,so the influence of workpiece speed on the workpiece surface coverage is small.Under the same condition of other processing conditions,the coverage will increase with the increase of spray angle.The time required to reach 100%coverage at 30° is 1.67times of that at 90°.（2）The Vivtorinox microhardness of the bearing inner ring samples with different coverage decreases continuously along the depth direction,and finally tends to be stable,fluctuating at 735±5HV,that is,the microhardness value of the core.After intensive grinding,the hardness of bearing inner ring with 100%-600% coverage increased by 14.22%,17.00%,18.13%,18.84%,20.52%,21.40% respectively compared with that without intensive grinding.At the same depth,with the increase of the coverage,the microhardness of the bearing specimen increases,but the increment slows down obviously.（3）With the increase of the coverage,the dislocation density of the bearing inner ring increased from 100% to 600%,which were 9.5647×10¹³m^-2,3.3178×10¹⁴m^-2,7.0564×10¹⁴m^-2,3.5091×10¹⁵m^-2 and 4.0642×10¹⁵m^-2,respectively.After intensive grinding,the surface of the material is subject to cyclic plastic deformation,and the dislocation on the surface forms slip and plug,resulting in dislocation tangle,which increases the resistance of dislocation movement.At the same time,due to the dislocation density and grain refinement,the number of grain boundaries is increased,and the dislocation movement is hindered and enhanced by the grain boundaries.（4）With the increase of the coverage,the residual stress on the inner ring surface of the bearing increases in the X and Y directions.For the inner race of bearing with a coverage of 600% and the race without intensive grinding,the maximum surface residual pressure stress in the X direction increases by 406mpa,and the maximum surface residual pressure stress in the Y direction increases by 411mpa.（5）After intensive grinding,the inner rings of thin-walled deep groove ball bearings（61910） with different coverage are obtained,with the coverage of 100%～600% respectively,and the comprehensive surface performance of the bearings with 600% coverage is the best.