Koyo JR25X30X20 needle roller bearing inner ring, 25 x 30 x 20 mm

These Koyo JR inner rings are metric series inner rings made from rolling bearing steel, with the bore, raceway and end surfaces ground after hardening. An inner ring works as the inner raceway for a needle roller bearing, giving a surface that meets the hardness, surface finish and roundness requirements when it is not practical to make the shaft to raceway quality.

Metric series inner rings can be used with metric series radial needle roller and cage assemblies, metric series needle roller bearings and metric series drawn cup needle roller bearings. The JR series is for use with caged metric needle roller bearings, and it has mounting chamfers at the ends of the raceway surface.

The range has 12 sizes with bore diameters from 7 to 50 mm. Koyo bearings are made by JTEKT Corporation.

Where this product is used

• Automotive applications
• Truck applications
• Power transmissions
• Industrial applications

Features

• Bearing steel, ground bore, raceway and end surfaces after hardening
• Provides an inner raceway where the shaft cannot be hardened and ground to raceway quality
• Outside diameter tolerance h5, with other features to ISO 492 Normal tolerance class
• For use with metric needle roller and cage assemblies, machined needle roller bearings and drawn cup bearings
• Bore diameters 7 to 50 mm and outside (raceway) diameters 10 to 60 mm

Key specifications

Available sizes

Selecting the right option

Choose the ring from the shaft (bore diameter d), the raceway diameter the bearing needs (outside diameter F, which should match the roller complement bore diameter Fw of the needle roller bearing) and the width B. Extended (wider) inner rings suit bearings with lip contact seals and applications where axial movement may be present.

The designation shows the sizes directly: for example JR12x15x16 has a 12 mm bore, a 15 mm outside diameter and a 16 mm width.

Fitting and use

An inner ring may be mounted on the shaft with a loose transition fit or an interference fit. These fits, with the correct fit of the bearing outer ring, give the correct operating clearance for most applications. Whatever the fit, locate the inner ring axially with shaft shoulders or other positive means, and keep the shaft shoulder diameter next to the ring no larger than the ring outside diameter.

For use with Koyo heavy-duty needle roller bearings, select the shaft tolerance from the heavy-duty needle roller bearing mounting table: g6 where the load rotates relative to the housing, and k6, m6 or n6 by shaft diameter where the load is stationary relative to the housing. For use with drawn cup bearings, follow the shaft tolerances given for inner rings in the drawn cup section of the Koyo catalogue.

Related products

Also available from Koyo: the Koyo NK range without inner ring, the Koyo NKS range with lube hole and the Koyo HK drawn cup bearing range.