Effects of raceway roundness and roller diameter errors on clearance and runout of a cylindrical roller bearing

Abstract

The actual radial clearance and runout of the bearing are different from design ones, because of the unavoidable raceway roundness and roller diameter errors of a cylindrical roller bearing. However, there is little knowledge about how the raceway roundness and roller diameter errors affect the radial clearance due to the lack of the analysis method. In this study, a mathematic model with algebraic equations is developed. The raceway curves are described by Fourier series. When the outer ring is turned a angle, iterative calculations are done until at least one roller contacts the raceways by judging whether the clearances between the rollers and inner raceway equal zero or not. Then the radial clearance and runout of the bearing can be determined when the outer ring is turned one revolution. The independent and synthetic effects of the raceway roundness and roller diameter errors on the radial clearance and runout of a cylindrical roller bearing are analyzed. Results show that the clearance and runout periodically vary with the increase of the flap number, which is also the harmonic number, of the rotating raceway. The ratio of the numbers of the raceway flaps and rollers determines the period. The clearance and runout of a cylindrical roller bearing are greatly affected by the rollers' diameter errors instead of their positions.