Research On Optical Measurement Technology Of Angular Contact Ball Bearing Ring

Angular contact ball bearings are the core support part of the rotation of many machines.This type of bearing has the advantages of high reliability,high precision and long service life.They can withstand both radial and axial loads and have high speed.Angular contact ball bearings consist of rings,rolling elements and cages.The accuracy of the ring affects the working accuracy of the whole bearing.Consequently,it is necessary to improve the accuracy of measuring the inner and outer rings and groove dimensions of bearing rings.This thesis studied the optical measurement technique of angular contact ball bearing rings.The main research content is as follows:（1）The measurement methods were to inspect the diameter and roundness of the inner and outer rings of the bearings using machine vision.The principles of machine vision measurement were analyzed in depth The measuring device for inner and outer rings of bearings based on machine vision inspection was designed.They were used for image acquisition.The discrete points in the edge normal direction of the digital image of the ring were fitted to Gaussian integral curves.The subpixel edge positions were determined by calculating the coordinates of the mean points.Calibration was performed using Class 1 accuracy blocks of 7,8 and 10mm.Pixel equivalents and light intensity compensation factors were calculated.The diameters of the inner and outer rings could be found by least squares fitting.The radius difference between the two concentric circles covering the contour of the measured circle was the roundness error of the ring.The inner ring diameters were compared with those measured by CMM.The difference between the dimensions obtained by the two methods was 2.2μm.（2）A method for measuring the diameter of the outer groove in the radial plane of the ring based on optical inspection technology was proposed.The diameter difference between the outer groove in the ring radial plane and the grinded ring was compared by the relative method.The size of the measured dimension and its error size were determined.The measuring device was designed based on the measurement principle,.It was mainly composed of positioning components,CMOS grating displacement sensor with a resolution of 0.1μm,etc.（3）Through finite element analysis,the measuring rod underwent a deformation of 2μm under a force of 1N.The measuring rod was connected with a double flexible hinge.The double flexible hinge underwent strict translational motion when subjected to the measured force.The error of bending and deformation of the measuring rod due to the measuring force was eliminated.Experimental verification was performed based on the relative values of the outer groove diameter of the ring（L_i）and the smooth ring diameter（L₀）measured by the sensor and the smooth ring diameter（d₀）measured by the CMM.The value of the outer groove diameter in the radial plane of the ring was calculated.The precision achieved was within±3.2μm.