Composite dry sliding bearings – maintenance-free and space-saving

Fig4Fig5Fig6The mating surface should cover theentire surface of the flangeThe transition between housing boreand support surface must be sufficientlylargeThrust washer secured by two grubscrewsSealsThe service life of composite dry slidingbearings is decisively influencedby the seals used. When selectingsuitable seals it is necessary to consider,for example, the design, theavailable space and the justifiableexpense.Composite dry sliding bearings, inparticular those of the POM composite,are able to embed contaminantparticles and are thus relatively insensitiveto contamination. They generallyrequire no special protection againstnormal airborne dirt. If, however, thebearing position is subjected to heaviercontamination it should be sealedoff from the outside. Simple and efficientsealing can be obtained if adjacentcomponents can also serve asseals (➔ fig 7 ). Radial shaft sealswith low cross section, e.g. of the Gdesign, provide adequate protectionfor composite dry sliding bearings innormal cases (➔ fig 8 ). If the demandsplaced on the sealing arrangementare high, it may be necessaryto resort to special seals of rubber,plastic or similar materials (➔ fig 9 ).Under very rough conditions, particularlywhere sand or clay contaminantsoccur, rubber or plastic sealsusually have a very short life. Good“sealing” will be achieved in suchcases by periodic relubrication, if theoperating conditions permit.Adjacent components serve as sealsA shaft seal with low cross sectionalheight can be usedSealing with a wiper-scraper seal ofnitrile rubberFig7Fig8Fig923