Special Issue; Products for Industrial Machinery - NTN

NTN TECHNICAL REVIEW No.742006
New Product
Development of New RCT Bearing
for Axleboxes and Insulated Bearing with Shields
Ryutaro OKA
In recent years railroad carriages have been increasingly
considered to be eco-friendly, energy efficient, and are viewed
as a good means of transportation. Demand for railroad
bearing business grows greatly in China and Europe.
High reliability is sought after in a bearing for railroad
applications because of public visibility. There is also a strong
demand from the railroad companies for longer time between
maintenance periods.
Therefore the problems facing railroad bearings is how to
effectively maintain reliability and extend the time between
maintenance periods. NTN has developed an Insulated Bearing with shields and the new RCT
Bearing, which could solve these problems and satisfy the Chinese and European markets.
This report discusses laboratory evaluation test results concerning the performance of Insulated
Bearings with shields and the new RCT Bearing.
1. Introduction
Recently, the usefulness of rolling stock has been
appreciated even more because trains are
increasingly regarded as an eco-friendly means of
transportation that excels in energy efficiency. In
particular, there have been serious efforts for the
construction of intercity railway infrastructure and the
introduction of high-speed railway systems in China.
Furthermore, in the European market, which accounts
for 50% of the world’s railway equipment demand,
higher train speeds are needed to accommodate the
recent expansion of the EU. Thus, in these markets,
the demands for rolling stock bearings have been
increasing dramatically.
The typical bearings for rolling stock include traction
motor bearings for power transmission systems, drive
system bearings used in the gearboxes (drives) that
transmit the motor output to the axles, and axle
bearings that support the weights of the train cars.
Each of these bearings is a critical component whose
performance directly affects the operation of railroads,
and, therefore, they must all be highly reliable. At the
same time, the end users who operate the trains are
demanding longer maintenance intervals. Therefore,
the manufacturers of bearings for rolling stock now
have to address the challenge of realizing longer
maintenance intervals while maintaining high levels of
bearing reliability.
Recently, we have developed unique bearing
products to address these challenges and to fulfill the
needs of the very promising Chinese and European
markets. They are our new RCT bearings for
axleboxes, which is a line of high performance
axlebox bearings and our sealed insulated bearings
for traction motors. This report describes the results of
evaluation tests for our new RCT bearing for
axleboxes and our sealed insulated bearings.
2. New RCT Bearings
In the European rolling stock axlebox bearing market,
metric-series bearings have been used commonly, and
such bearings are also often adopted in the Chinese
rolling stock market. We have recently developed a new
line of RCT bearings for axleboxes that satisfy the EN
standards, which are commonly adopted in the
European and Chinese rolling stock markets.
*RCT bearings: sealed double-row tapered roller
bearings used on rolling stock axles.
Industrial Engineering Dept.
-84-