SWING BEARING AND METHOD OF PROCESSING RACEWAY GROOVE OF THE SAME

摘要

A swing bearing having double-row raceway grooves, wherein a relative difference between inter-raceway groove distances is appropriately determined so that the bearing has an extended life achieved to an extent which is cost-wise feasible and does not sacrifice productivity.  The swing bearing has balls (3) interposed between double-row raceway grooves (1a, 1b, 2a, 2b) in an inner ring (1) and an outer ring (2).  The distance (ei) between the double-row raceway grooves (1a, 1b) in the inner ring (1) or the distance (eo) between the double-row raceway grooves (2a, 2b) in the outer ring (2) is 1 to 1.7 times the diameter (Dw) of the balls (3), the diameter (Dw) of the balls is from 30 mm to 80 mm, and the difference (?e) between the inter-raceway groove distance (ei) and the inter-raceway groove distance (eo) is from 5 µm to 50 µm.  The double-row raceway grooves (1a, 1b (2a, 2b)) are simultaneously processed by an alundum-based grindstone.