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Railway Industry

Bearings play an important role in both passenger and goods transport. They have to withstand heavy loads: they work at high speeds, under a great weight, are subjected to both static and dynamic loads and 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 programme, 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. The 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, the rail companies also pursue efficiency goals 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 optimisation.

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 high 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. Apart 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 possibility of a strong passage of electrical current and high speeds. In order to meet these requirements, NSK has 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 has developed insulated bearings with a ceramic coating and PPS resin coating. Both of the above 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

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

Wheelset bearings are subjected to not only radial loads through rail joints and points but also dynamic and static radial loads due to the weight of the vehicle. What’s more, 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. What this means for wheelset bearings is that they are used in a wide variety of conditions such as dirt, moisture and ambient temperatures in different countries. 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 innovative seals and end caps to prevent the escape of grease and ingress of water. 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: thanks to their high quality, they offer an outstanding performance, a long service life, are easy to handle and suitable for high speeds. NSK's new Cylindrical Roller Bearings have been specially designed to save weight, being a compact space saving design and can operate at high speeds under oil lubrication.

Railway Wheelset

Sealed-Clean Rotating End Cap Tapered Roller Bearings

Sealed-Clean Rotating End Cap Tapered Roller Bearings: They offer outstanding performance, durability and ease of handling.  >>

Insulated Bearings for Traction Motors - PPS

PPS-resin coating insulated bearings developed to prevent electric pitting  >>

Insulated Bearings for Traction Motors - Ceramic

Ceramic coating insulated bearings 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

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Bearings for Railway Rolling Stock

Axle Bearings, Sealed-Clean Rotating End Cap Tapered Roller Bearings & Cylindrical Roller Bearings, Spherical Roller Bearings, Bearings for Traction Motors

Bearings for Industrial Gearboxes

Bearing types, Arrangements, STIFF, Dimensioning, Fits of radial Beairngs with Shafts

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