Railway rolling stock

The use of bearings for rolling stock is varied, from door moving to axle bearings,  roller bearings for traction motors and gearboxes as well as axle bearing sets.

Gearbox bearings need to withstand high loads and high speeds as well as be resistant to swing, vibration, shocks and extreme temperatures. Rolling bearings with massive cages are the most common solution. 

• Cylindrical roller bearings
• Tapered roller bearings
• Four-point contact ball bearings
• Angular contact ball bearings
• Large single row deep groove ball bearings

Traction motor bearings operate in severe conditions such as high radial and axial loads, high impact loads, high speed and extended periods of operation without maintenance. That is why NSK uses highly pure bearing steel. Inner and outer rings are treated for heat dimensional stabilisation and high-strength cages are applied. Outside surfaces and both end faces of outer rings are coated with ceramic or heat-resistant resin to prevent electric pitting.

 

To prevent electric pitting, NSK developed ceramic coating insulated bearings and PPS-resin coating insulated bearings. Traction motors often use insulated cylindrical roller bearings and insulated ball bearings.

Rolling stock axle bearings are subject to radial impact loads caused by rail joints, switches and sometimes wheel flats, as well as to the static and dynamic radial loads of vehicle weight. They are also liable to receive axial loads generated by lateral movement as trains run on curved rails or in a snaking motion. These loads together form complex combinations that act on axle bearings. Additionally, as axle bearings play a critical role in the safety of railroad operation, they are periodically disassembled for inspection. This means simple and dependable procedures for disassembly, inspection and re-assembly are important design factors.

 

All types of radial roller bearings, including tapered roller bearings, spherical roller bearings and cylindrical roller bearings, have been used in rolling stock axles due to the particular merits of each type.

 

To improve operating efficiency, bearings must offer longer inspection intervals. To meet all these needs, we offer the following six types of axle bearings:

 

We are specialists in efficient and safe tools for bearing mounting and dismounting, as well as monitoring and diagnostics tools for controlling the operation of rotating parts. Our range of products and services can help you save on maintenance costs.