Part of bolt as bearing race of the CYJ-Curving Roll is quenched. Outer surface of thick wall outer ring of the trolley is cambered surface in avoidance of concentrated stress. There are various models of specs of the curve roll, such as with single or double packing ring, without packing ring and with packing annulus. The ones with packing ring can be stored with more lubricating grease, provide long-term lubricating and prolong the lubricating intervals. Material of packing ring is N220 or polytetrafluoroethylene, its operating range of temperature is from -30癈 to +100癈 or from -30癈 to +180癈. Airproofed curving roll can bear heavier load while the speed is relatively lower and they must be lubricated usually.