3. Pulley core sleeve:
(1) Powder metallurgy oil-containing iron sleeve wheel core: low cost, widely used, suitable for small tonnage pulleys with slower speed.
(2) Needle roller bearing wheel core: flexible rolling, compressive resistance.
(3) Wear-resistant composite copper-sleeved wheel core: excellent wear resistance, high load, low friction coefficient, suitable for heavy lifting load, but can not form a smooth film, it is mostly used for multi-wheel large block.
(4) Roller bearing wheel core: standard bearings, can be selected according to the lifting tonnage, different standards, suitable for high-speed work, free of protection, but the cost is higher.
