Spherical roller bearings

A spherical roller bearings consists of an outer ring having a continuous spherical raceway within which operate two rows of barrel-shaped rollers guided by an inner ring with two raceways. This bearing has self-aligning properties, and therefore is suited for use where misalignment between the inner and outer rings occurs from housing installation error or shaft bending. Spherical roller bearings have a large capacity for radial loads, axial loads in either direction, and complex loads. They are also suited for applications where vibration and shock loads are encountered. However, if used under a large axial load, the load on the rollers of the row that is not subject to the axial load becomes small, and the resulting skidding on the rollers may cause insufficient lubricating condition. When bearings are operated under small loads (about Fr 0.04Cor), or under axial loads only, prevent rolling elements from smearing by operating in conditions where-

– Fa: Actual axial load [N]

– Fr: Actual radial load [N]

– e= 9/8…………………for roller bearings

=10/9………………..for ball bearings

This is most apparent when using large size spherical roller bearings due to the large roller and cage mass. Pressed cages or machined cages are standard depending on the bearing type and dimensions. However, a standard cage may not be used under high-speed specifications or in conditions under severe vibration or impact. NTN E type bearings have a polyamide 46 (PA46) cage. This new resin offers excellent heat resistance, with an allowable operating temperature up to 150°C, and mechanical resistance, which makes it ideal for high-speed rotation environments or high-vibration applications. It also exhibits an excellent compatibility with oils.