Current single row ball slewing bearing(https://www.slew-bearing.com/Single-Row-Ball-Internal-Gear-Slewing-Ring-for-Combination-Sewer-Cleaner-pd6849698.html) follows two industry standards JJ36.1-91 "Slewing Bearing for Construction Machinery" and JB/T 2300-2011 "Slewing Bearing". At present, except