IKO NA4903 Needle Roller Bearing with Inner Ring, 17 x 30 x 13 mm

This page holds two series of IKO machined type caged needle roller bearings with an inner ring: 22 sizes of NA49 (8 to 110 mm bore, models NA498 to NA4922) and 7 sizes of NA48 (120 to 190 mm bore, models NA4824 to NA4838). All are open, with no seals. After the NA, the model number gives the series and then the bore diameter number: NA498 is NA49, NA4824 is NA48.

Machined type needle roller bearings have a low sectional height and large load ratings. The outer ring is rigid and can be used even in light alloy housings. The inner ring lets the bearing run on a shaft that cannot be heat-treated and ground. The inner ring and the outer ring with cage are separable, with a small relief clearance on both sides of the inner ring raceway to make mounting easier. The allowable axial shift S between the rings is given for each size.

NA49 and NA48 are different dimension series with different outside diameters and widths, so check those in the sizes table.

Where this product is used

• Shafts that cannot be heat-treated and ground
• Compact shaft supports with a low sectional height
• Light alloy housings

Features

• Machined type caged needle roller bearing with inner ring (NA49 and NA48 series), 29 sizes
• Bore 8 to 190 mm, outside diameter 19 to 240 mm
• Matching inner ring shown for each size, for shafts that cannot be heat-treated and ground
• Basic dynamic load ratings 6.18 to 249 kN, static 5.03 to 726 kN
• Allowable rotational speed 1,800 to 40,000 rpm (oil lubrication)

Key specifications

Available sizes

d is the bore, D the outside diameter, C the outer ring width and Fw the roller set bore diameter; C and C0 are the basic dynamic and static load ratings, and speed is the allowable rotational speed.

Selecting the right option

Choose the size with the Inside Diameter (mm) option, which is the bore of the bearing (the inner ring bore). The model number is shown with each variant and in the sizes table.

This page mixes two series. Models that start NA49 and NA48 differ in dimension series, so confirm the outside diameter and width as well as the bore.

Bearings with an inner ring suit shafts that cannot be heat-treated and ground. If your shaft is hardened and ground, a type without an inner ring (RNA and TAF) can be used instead.

The assembled inner ring is shown against each size in the sizes table. The bearing and its inner ring are listed as separate parts, so request a quote to confirm what is supplied if you need both together.

Fitting and use

These bearings are not prepacked with grease, so lubricate them before use. The allowable rotational speed in the tables is for oil lubrication; for grease lubrication use up to 60% of it. The outer ring has one oil hole with an oil groove, and the inner ring has no oil hole.

Heat expansion in use, or mounting errors, can shift the inner or outer ring axially so that the rollers do not contact the raceway along their whole length. Keep any axial shift within the allowable value S given for each size in the specifications.

Ask AIMS for the shaft and housing tolerances that suit your application.

Related products

Parts that go with this range: NA69: the open NA69 series; NA49 UU: sealed NA49 series; RNA: without an inner ring; LRT inner rings for the inner ring series.