GB/T 25767-2010 “Rolling Bearings Tapered Rollers” divides tapered rollers into 0, Ⅰ, Ⅱ, Ⅲ grades according to their manufacturing dimensions, tolerances and surface roughness, and the precision is from high to low. At present, the actual quality indicators of most tapered roller manufacturers are as follows:
1) Single plane roller diameter variation VDwsp. Most enterprises can reach within 2 μm, meeting level III; some enterprises can reach within 1.2 μm, reaching level II; a small number of enterprises can reach within 0.5 μm, meeting level I.
2) Roundness error (the roundness is according to JB/T 6642-2018 “Measurement and Evaluation Method of Roundness and Waviness Error of Rolling Bearing Parts”, taking 2 to 15 waves). Most enterprises can reach within 2 μm, meeting level III; some enterprises can reach within 1.2 μm, reaching level II; a small number of enterprises can reach within 0.5 μm, meeting level I.
3) The runout SDw of the outer surface of the large end of the roller. Most enterprises can reach within 6.5 μm, meeting level III; some enterprises can control within 4 μm, reaching level II; a small number of enterprises can reach within 2.0 μm, meeting level I.
4) The Ra value of the outer diameter surface roughness. Most enterprises can reach within 0.16 μm, which meets level III; some enterprises can control within 0.125 μm, which meets level II; a small number of enterprises can reach within 0.08 μm, which meets level I.
5) The Ra value of the roughness of the large end surface of the roller. Most enterprises can reach within 0.32 μm, meeting level III; some enterprises can control within 0.16 μm, reaching level II; a small number of enterprises can reach within 0.1 μm, meeting level 0.
6) Plain line shape. The shape of most enterprises’ rollers is a great circular arc, and individual enterprises can produce logarithmic curve rollers.
7) Roller gauge value batch diameter variation VDwL. Most enterprises can be stably controlled within 3 μm, meeting level III; a small number of enterprises can reach within 2 μm, meeting level II.
8) Roller gauge value batch taper angle variation V2φL. Most enterprises can be stably controlled within 3 μm, meeting level III; a small number of enterprises can reach within 2 μm, meeting level II.
