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Railway Industry

Bearings play an important role in both goods and passenger and transport. They must withstand heavy loads, work at high speeds, under a great weight,  and are subjected to both static and dynamic loads. All of these factors play an essential part in the safety of rail vehicles.

NSK is the leading bearing manufacturer for the Japanese Shinkansen high-speed trains and manufactures wheelset bearings for trains in the British Intercity Express progra, amongst others. Since both the wheelset bearings and the traction motor bearings have a direct effect on a train’s safety, NSK works with the latest technologies, innovative seal solutions and high-strength special steels. Ceramically insulated NSK bearings for traction motors have also proven themselves through a high insulation resistance and reliable use at high speeds and strong shock loads.

Apart from safety aspects, rail companies also pursue high efficiency with respect to higher speeds and prolonged maintenance intervals. These requirements are also met by NSK’s wheelset and traction motor bearings through permanent further development and optimization.

Bearings for Traction Motors

Operating conditions: high radial and axial loads, strong passage of current

Traction motor bearings in rail transport have to be powerful, environmentally friendly and cost-effective. The weight of rail vehicles and long maintenance-free operating hours have to be taken into account to guarantee a high degree of reliability and safety. Aside from reducing the weight of the drive train, traction motors in rail transport are subjected to high radial and axial loads as well as the potential for strong passage of electrical current and high speeds. In order to meet these demanding requirements, NSK developed insulated bearings with a ceramic coating and high-strength cages.
Both Cylindrical Roller & Deep Groove Ball Bearings have proven themselves in traction motors for rail vehicles since they are ideal for high speeds and loads and are easy to install and dismantle.

Insulated Bearings for Traction Motors – Ceramic coating 

Insulated Bearings for Traction Motors – PPS coating

Traction motor bearings often fail on account of damage caused by the passage of current (electro-pitting). To prevent electro-pitting, NSK developed insulated bearings with a ceramic coating and PPS resin coating. Both solutions provide a high insulating resistance of over 100Mohms with a breakdown voltage in access of 4KV.
High-strength cages were designed to absorb the loads that occur, such as vibrations. Spherical roller ends and bevelled ribs increase the thrust load capacity, and the high quality along with long service life guarantee the safety and reliability of the traction motors.

Traction Motor

Wheelset Bearings

Operating conditions: radial shock loads and axial loads through swaying movement

Wheelset bearings are subjected not only to radial loads through rail joints but also dynamic and static radial loads due to the weight of the vehicle. Additionally, they have to withstand axial loads caused by swaying movements and curves. Since wheelset bearings are subject to this complex combination of loads, both the dimensions of the axle journal and bearing housing as well as the complex load conditions are taken into account during their design.

Rail transport is international which means wheelset bearings are used in a wide variety of conditions including dirt, moisture and ambient temperatures. NSK offers wheelset bearings with corresponding sealing solutions as well as different lubricants for these requirements. Tapered Roller Bearings, Spherical Roller Bearings and Cylindrical Roller Bearings are particularly suited for use in wheelsets.

Sealed-Clean Rotating end Cap Tapered Roller Bearings for Wheelsets & Cylindrical Roller Bearings for Wheelsets

Sealed-Clean Rotating end Cap Tapered Roller Bearings can be ideally integrated to adjacent components and are fitted with high quality seals and end caps to prevent the escape of grease or ingress of water contaminant. Common bearing problems can be avoided in this way and maintenance intervals can be prolonged to match the operating life of the wheels themselves. Since axle bearings that come into direct contact with the axle have to be designed for difficult conditions, NSK's Taper Roller Bearing Units are an ideal solution. They offer outstanding performance, a long service life, easy handling and are suitable for high speeds. NSK's new Cylindrical Roller Bearings have been specially designed to save weight, with a compact space saving design that can operate at high speeds under oil lubrication.

Railway Wheelset

Sealed-Clean Rotating End Cap Tapered Roller Bearings

Offer outstanding performance, durability and ease of handling.  >>

Insulated Bearings for Traction Motors - PPS

Developed to prevent electric pitting  >>

Insulated Bearings for Traction Motors - Ceramic

Developed to prevent electric pitting  >>

High Temperature Sealed Deep Groove Ball Bearings

Specially created to run in a contaminated environment, and under high temperatures, up to 150°C.  >>

Cylindrical Roller Bearings for Wheelsets

High-speed capability, easy maintenance and ability to either allow or restrict axial movement. >>

Deep Groove Ball Bearings

The most common form of rolling bearings, deep groove bearings are used in a variety of applications; particularly those where high speeds and low power loss are required  >>

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Bearings for Railway Rolling Stock