The Influence of Axial Deformations on the Flatness Deviation of the Bearing Race End Surface During Grinding

Upon heat treatment, flatness deviation and curvature appear in the bearing race end surfaces due to the effect of the residual temperature stresses. The curvature of the end surfaces considerably complicates the grinding process because the race is additionally bent due to the magnetic field of the machine-tool table. Sample workpieces of the ShKh15 steel are submitted to flat grinding with the periphery of a straight wheel. Algorithms and mathematical models for the determination of the axial deformation when grinding large bearing races with initial flatness deviations of the end faces are presented. Outer races of a conical singlerow ShKh15 steel roller bearing are used as an example to analyze the end surface shape of non-rigid races. The theory of small curvature bars is applied to determine the maximal axial elastic deformations when the race is bent. The maximal axial elastic deformation of the race is determined using the method of More. The statistical uncertainty of the race is expanded through the method of forces. The conditions providing the required flatness tolerance of the end surface are determined for the bearing race. These conditions take into account the axial deformation of the race under the effect of the machine-tool magnetic field and the radial component of the grinding force.

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