Efficient performance and long life of the roller bearing depend to a large extent upon the exclusion of foreign matter from the internal bearing surfaces. Grease, or oil, serves the dual purpose of lubricating these surfaces and protecting them from corrosion. Thus the seal must prevent dust, grit and moisture from entering the bearing and at the same time prevent grease or oil from escaping.
Cooper supplies various mounting options and for all, except the hanger mountings, the bearing is housed in a cartridge supported by the mounting unit. Cartridges have a spherical outer surface that fits into a conforming surface in the mounting unit (such as pedestal or flange) in the manner of a ball and socket joint.
Any shaft misalignment tends to move the cartridge, seal and bearing together, maintaining the seal on an axis parallel to the shaft. Standard pedestals and flanges are designed to allow up to 2½° misalignment between the shaft and housing, under constant or slowly changing alignment conditions, without compromising sealing.
Compare this with the situation that occurs with a double row spherical bearing in a standard pedestal. If the pedestal is not accurately aligned with the shaft, contact between the seal and the shaft tends to be lost at one side and the seal presses more heavily against the shaft at the other. In the worst case a gap may open, compromising the sealing or the seal may bind on the shaft. Although felt seals are shown in the illustration, a similar situation occurs with labyrinth or lip seals.
Cartridges for shaft sizes up to 300mm/12” are usually supplied with a general purpose felt seal. The felt groove will also accommodate high temperature packing seals, lipped seals or suitable blanking plates.
Triple labyrinth seals are often supplied as an alternative and are precision non-rubbing seals capable of high-speed operation. Due to the aligning feature described above, extremely close tolerances can be maintained between the housing and the shaft. The result is an effective sealing element which is one of the best in the anti-friction bearing industry.
Cartridges for shaft sizes over 300mm/12” are supplied with grease groove seals as standard.
Cooper offers a wide range of standard sealing options. For special applications seals may be made from other materials and alternative special seals can be supplied to suit specific conditions.
Where shafts terminate at the bearings, blanking plates may be used to close off the cartridge ends.
Blanking plates are available to suit standard single groove and TL cartridges.
The SKF Cooper upgraded E-series includes an extended range of series 01 and 02 bearings in bore sizes up to 150 mm, complementing the entire product range with sizes up to 300 mm.