Bearings for railroad vehicles

Three kinds of bearings
Bearings for axles, gear boxes and traction motors
Exclusive design for each application.
Cylindrical roller bearings are mainly used for axles with heavy radial load (Double-row tapered roller bearings have also used recently).
Tapered roller bearings are used for gear boxes where large thrust loads are expected.
Deep-groove ball bearings and cylindrical roller bearings are used for traction motors.

Three kinds of bearings
Bearings for axles, gear boxes and traction motors
Exclusive design for each application.
Cylindrical roller bearings are mainly used for axles with heavy radial load (Double-row tapered roller bearings have also used recently).
Tapered roller bearings are used for gear boxes where large thrust loads are expected.
Deep-groove ball bearings and cylindrical roller bearings are used for traction motors.

Changes of bearings for Shinkansen (Japanese bullet train) axles

0 family the first Shinkansen 1964 -

Two kinds of bearings (double-row cylindrical roller bearing JC9 and deep-groove ball bearing JB4) are used.
Radial load is supported by JC9 and axial load is supported by JB4.
Maximum speed: 220km/h

300 family Shinkansen 'Nozomi' 1992 -

Radial load is supported on raceway and axial load is supported with ribs on inner and outer ring.
Double-row cylindrical roller bearing JC34
Maximum speed: 270km/h

700 family Shinkansen 'Nozomi' 1999 -

Double-row tapered roller bearing JT21 support radial and axial loads on raceway.
Excellent running stability due to the minimum axial clearance
Outstanding high-speed-operation performance
Compact
Maximum speed: 285km/h

For axles
Double-row cylindrical roller bearings or Double-row tapered roller bearings are used according to the vehicle characteristic.
Cylindrical roller bearings are widely used because of their capability for high speed rotation and ease of maintenance.
Recently, tapered roller bearings are also used because they are suitable for high speed operation and they can be used for a long period of time without disassembly.
(JC, JT, and JB types are made to the specification of Japan Railway Companies, AP type for AAR standard and FCD type is made to NACHI original specification.)

For Gear Boxes
There are bearings for a gearwheel and a pinion. Radial load and heavy axial load are applied simultaneously, and many tapered roller bearings are used.
(QT type made to the specifications of Japan Railway Companies and ED type to NACHI original design.)

For Traction Motors
- Ball bearings combining cylindrical roller bearings without rib on inner ring are used in many cases.
  They are specially designed to sustain high speed rotation and severe vibration with grease lubrication.
  (Suffix JT at the end of bearing number means NACHI ball bearings for traction motors and suffix T, TS, and TSL for NACHI cylindrical roller bearings for traction motors.)

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