NACHI NJ208 NJ Cylindrical Roller Bearing 40x80x18 mm

The NACHI NJ208 is a single row cylindrical roller bearing in NJ configuration: two flanges on the outer ring and one flange on the inner ring. It measures 40 x 80 x 18 mm (bore x outer diameter x width), with a basic dynamic load rating of 43,500 N and a basic static load rating of 43,000 N.

The inner ring and roller set can be separated from the outer ring. It takes axial load in one direction and locates the shaft in that direction only. Its radial internal clearance is Normal, CN (25 to 50 µm).

Where this product is used

• Electric motors and generators
• Gearboxes and industrial transmissions
• Pumps, fans and compressors
• Machine tools and general industrial machinery
• Conveyor drives and other heavy rotating equipment

Features

• NJ configuration, with two flanges on the outer ring and one flange on the inner ring. The inner ring and roller set can be separated from the outer ring.
• Takes axial load in one direction and locates the shaft in that direction only. Axial load is carried by sliding contact between roller ends and flanges, so the allowable axial load is limited
• Line contact between rollers and raceways gives a high radial load capacity for the size: Cr 43.5 kN, Cor 43 kN

Key specifications

Selecting the right option

The NJ configuration has two flanges on the outer ring and one flange on the inner ring. It takes radial load plus axial load in one direction, and so locates the shaft in that direction only. Axial load is carried by sliding contact between roller ends and flanges, so the allowable axial load is limited: for heavy or continuous axial load, send AIMS the application details first.

These are Normal (CN) clearance bearings. If the inner ring will run hotter than the outer ring, the shaft deflects a lot, or the fits are tight, the C3 versions in the Related products section may suit better.

Fitting and use

Check the load and speed against the catalogue figures before ordering and apply a suitable safety factor. Cylindrical roller bearings are mainly for radial load: any axial load must be well within what the flanges can carry by sliding contact, and the limit depends on lubrication and speed as well as the bearing.

The catalogue limiting speeds are for machined-cage bearings; for a pressed steel cage multiply them by 0.8. Pressed steel is the catalogue standard cage for these sizes, so the Model Details show both figures for each size.

Where axial load is applied, keep enough radial load on the bearing, supply plenty of lubricant between the roller ends and flanges, use a lubricant with good film strength, mount the bearing accurately, allow a running-in period and keep the radial clearance small.

These bearings are open: the housing arrangement has to supply and hold the lubricant and keep contamination out. Fit the rings with the housing and shaft tolerances recommended for your application, and keep the shaft and housing seats clean and square.

If you are replacing a bearing, check the full number stamped on it, including any letters after the digits, and send AIMS the number or the dimensions if you are not sure.

Related products

More sizes in the same configuration: NACHI NJ cylindrical roller bearings (19 sizes), NACHI NJ C3 cylindrical roller bearings (12 sizes) and NACHI NJ EG C3 cylindrical roller bearings (2 sizes). Other configurations: NACHI NU cylindrical roller bearings (23 sizes) and NACHI N cylindrical roller bearings (25 sizes). For combined radial and axial loads on one bearing, see the NACHI tapered roller bearings (metric series).