 Needle bearings represent a variant of cylindrical roller bearings, in which the roller length is at least six times its diameter. As far as the structure, size and variety of types as well as application possibilities are concerned they represent unquestionably the largest group of rolling bearings. Each variant has individual features, but generally needle bearings demonstrate high load capacity at relatively small sizes. It helps obtain a compact bearing-closed pairs construction, and wide variety of sizes and types makes it possible for designers to use new technological solutions. The contact line of tracks and needles is modified (needles are profiled on their ends), what not only eliminates harmful end stresses but also enables minimal misalignment between the shaft and the bearing mounting. Bearings are equipped with steel cages or cages made of steel sheet. In smaller-sized bearings cages made of polyamide strengthened with glass fiber are also in use.
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