Quiet needle roller bearings
INA series NK and NKI machined needle roller bearings with plastic cages have been introduced in some under-roller and bore diameter sizes. Structure-borne noise in these bearings is said to be 70% below values obtained for comparable bearings with a steel cage.
The thermoplastic material used for the cage is heat-stabilized, glass-fibre reinforced polyamide PA66-GF/H. The material is said to have good strength and elasticity characteristics. To increase the bearing’s load carrying capacity, the cages have been designed to accommodate more rolling elements than steel cages. For size NK 50/35 TN for instance, the dynamic load rating is approximately 18% above that for the design incorporating the steel.
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