High precision needle roller bearing NA4913A/p2

1.strong technology service support. 2.low frictional torque. 3.produce both metrc and inch size 4.ISO9001:2000 certification Needle Bearings

Needle bearings are roller bearings with rollers that have high length-to diameter ratios. Needle bearings are used in farm and construction equipment, automotive transmissions, small gasoline engines, gear pumps, small appliance and tool motors, alternators, and aircraft controls.

Needle bearings are usually lubricated with grease, but oil or oil-mist lubrication is preferred for heavy-duty or high-speed applications. Many light-duty needle bearings never require relubrication, but high loads or speeds demand it.

Compared with other roller bearings, needle bearings have much smaller rollers for a given bore size. Needle bearings have the highest load capacity for a given radial space of all rolling-element bearings, but their use is limited to bore diameters less than 10 in.

All needle bearings are variations of two basic designs. The first needle bearing design, full complement, has a full complement of needles and contains no retainer. The second needle bearing design, caged needle, contains a retainer or cage for roller guidance and spacing. Caged needle bearings have smaller roller complements and lower load capacities than full-complement bearings. Needle bearings have the advantage of a higher speed capacity; retainers prevent high-velocity rubbing between adjacent needles and provide more effective roller guidance. Needle bearings also have greater lubricant capacity.

Loose - needle bearings are simply a full complement of needles in the annular space between two hardened machine components, which form the bearing raceways. Needle bearings provide an effective and inexpensive bearing assembly with moderate speed capability, but they are sensitive to misalignment.

Caged assemblies are simply a roller complement with a retainer, placed between two hardened machine elements that act as raceways. Their speed capability is about three times higher than that of loose - needle bearings, but the smaller complement of needles reduces load capacity for the caged

High precision needle roller bearing NA4913A/p2