Precision Cylindrical Roller Bearings

In the machine tool spindle applications, double row precision cylindrical roller bearings will be used to generally contact ball bearings or turbocharger bearings and precision angular composite applications. These bearings can withstand greater radial load and allows a higher speed. Bearing in two rows of rollers arranged in a cross pattern, rotation fluctuation frequency significantly higher than Four-Row Tapered Roller Bearings, amplitude reduced by 60% to 70%. Such bearings generally come in two forms: NN30, NN30K two series bearing inner ring with ribs, outer ring separable; NNU49, NNU49K two series bearing outer ring with ribs, separable inner ring, which NN30K and NNU49K series inner ring tapered bore (taper 1:12), with the tapered journal spindle with axial movement inner ring, the inner ring can swell, so the bearing clearance can be reduced even bearing preload (negative clearance state). Cylindrical bore bearings usually thermal loading, using an interference fit reduced bearing clearance, or preload the bearings. NNU49 inner ring separable bearings, usually mounted on the inner shaft and then to finish the race in order to improve the accuracy of spindle rotation.