Four giant-sized roller bearings from Schaeffler have been delivered for use on the world’s largest roller mill that is set to operate in a copper mine in Arizona, USA.
Developed in close collaboration with roller mill manufacturer, Metso Minerals, the double row spherical roller bearings feature a width of 710 mm, an outside diameter of 1,950 mm, a bore diameter of 1,250 mm and a total weight of around 7.85 tons.
Covering a floor area of 60 sq m, the new roller mill is specifically developed to crush the mined copper ore. It operates at a speed of 20 rpm and has been designed to yield 10,000 tonnes of crushed copper ore per hour. Such large volume requires equally large and heavy rollers. To suit the steel rollers, which have a diameter of three meters and weight of 160 tons, the application engineers at Schaeffler selected spherical roller bearings with outside diameter of almost two meters.
The extremely durable Schaeffler double row spherical roller bearings feature an optimized internal design and solid brass cages that are guided on the inner ring. Offering high load carrying capacity, the bearings have a basic dynamic load rating of 37,500 kN while the bore has been tapered with a 1:30 ratio.
The spherical roller bearings’ size posed a special challenge to Schaeffler’s production factory in Wuppertal, Germany. The engineers at the plant had to use a specially built lifting device to assemble and position the roller bearings, which were manufactured at the company’s plant in Eltmann, Germany.
Filed Under: Motion Control Tips, Bearings