What are Needle Roller Bearings?April 21, 2016
Needle roller bearings are designed as skinny cylindrical components, rolling elements that arrange themselves in a concentric circle within a ring-like raceway. The narrow diameter of this circular array reduces radial space, obviously, but the upshot of the design is a significant gain in load bearing capacity.
Reduced Cross-Sectional Area
Compact in form, the thin bearings are long and thin, hence the bestowment of the “needle” engineering term. The reduced radial spacing equals greater contact between the rollers and the rotating surface, a design characteristic that equals enhanced loading properties. Friction is ably handled by the form, but there’s also added versatility due to the compact shape. Just to clarify, we’re talking about the option to fabricate certain needle roller bearings without an inner race. This is a logical design choice as the rollers already exhibit strong contact properties, a rounded seal that’s as effective as any hardened steel ring.
Reduced Weight and Reduced Space
Applications extend across the engineering gamut, with limited access scenarios receiving the biggest gains. Car transmissions and power tools enjoy this benefit, as do the smaller rolling bearings used in electronic devices. This latter family of products includes printer servo motors and the moving parts in DVD drives. Greater reductions in the form can be found by machining the component as a cage-and-roller product, a variant that eliminates all excess surface materials, including the outer raceway. In fact, this is a common configuration, one used in hollow shafts, as the shaft serves as an outer race. Otherwise, the drawn cup type is recommended. Case hardened drawn cup needle roller bearings employ an outer shell or race, a form that’s still compact but capable of providing full mechanical retention as can be applied in countless radial friction-cancelling scenarios.
Full Spectrum Products
This is a bearing form with versatility, a skinny cylindrical ring of rolling bearings that can adapt to numerous usage domains. The race-free cage version carries a full complement of needle bearings, but we can flip to the far end of the spectrum and find heavy-duty versions, strong-willed variants that suit engines and car transmissions. Meanwhile, the subtly modified thrust family applies the same load carrying properties alongside a newly injected aptitude for handling shock, which makes this particular product an ideal fit for suspension systems and axle mounts.
The needle form is an important member of the bearing family, a form that delivers more versatility than any other roller in its class.
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