Research Of The Bearing Raceway Shape Error Evaluating Algorithm

Geometric error of bearing parts is an important technical indexes for theaccuracy of the bearing rotation. In this paper, the geometric error of bearing racewayis taken as the research object, and researche the geometric description of its shapeerror. The evaluation of the least square and minimum area for shape error are givenon the combination of the solving process of form error. There are several aspectsresearch for the evaluation of bearing raceway shape error as follows:1. Studying the structural style of bearing raceway as well as its applications, theconcept about the form error of bearing raceway has been proposed, which combinedto the definition of form error.2. According to the definition of least-squares form error, least-squares evaluationabout the form error of bearing raceway has been proposed.The least squares methodhas been adopted to fit the center of each line contour；a3D circle and its equationwill be worked out by using the least squares method to fit the center of each linecontour；to solve the intersection coordinates where the3D circle and the plane ofeach line contour intersect at；to calculate the difference between maximum andminimum among the distances which are from the measurement points on the contourof each line to each corresponding intersection, find the maximum range value amongthem and the central region which formed by rotating the line contour of maximumrange value around the Z-axis for360degree, the least squares form error of the entirebearing raceway will be worked out.3.According to the criterion of minimum condition form error, minimum zonesevaluation about the form error of bearing raceway has been proposed.Adopting theleast-squares method and the three-point setting a circle to determine the initial center,the center of contours is obtained by means of geometry optimization search, as wellas the line profile center; adopting the three-point setting a circle to determine theinitial center, the center of contours is obtained by means of geometry optimization search,as well as the center and radius of3D circle;to solve the intersectioncoordinates where the3D circle and the plane of each line contour intersect at;tocalculate the difference between maximum and minimum among the distances whichare from the measurement points on the contour of each line to each correspondingintersection, find the minimum range value among them and the central region whichformed by rotating the line contour of minimum range value around the Z-axis for360degree, the minimum zones form error of the entire bearing raceway will be workedout.4. In the case of the external error or no external error, the form error of bearingraceway is assessed, through simulation to verify the bearing raceway shape error ofleast squares evaluation and the smallest region, in theory, prove its correctness.In the paper, because the two evaluations about the form error of bearing racewayare based on simple geometric operations, it can effectively and accurately achieve theaccurate assessment about the global error of the entire raceway contours.