Railway bearings - axle gearbox bearings characteristics and applications
With the development of society, the railway machinery manufacturing industry continues to improve, relative to the railway bearing manufacturing technology is also constantly improving, in which the main role of the rolling bearing in the gearbox is to be able to stably transmit the output torque when the locomotive is running at high speed, which means that they must bear the changeable impact load in the complex environment. The main bearing types are tapered roller bearings, four-point contact bearings and cylindrical roller bearings. Bearing arrangements vary depending on the design and operating conditions of the gearbox.
Axle gearbox bearings
The main application performance of bearings for gearboxes is:
High speed; High load-bearing;Vibration and shock resistance;High temperature resistance.
The choice of bearing is determined according to the size of the relevant domain of the gearbox, taking into account the above application factors, and generally requires a calculated life of more than 2 million km.
Axle gearbox bearing applications
Tapered roller bearings are separable, and their inner ring roller cage assembly and outer ring can be assembled separately. The corrected linear contact between the rolling elements and the raceway avoids edge stresses. Tapered roller bearings can withstand both high radial and axial loads. Because these bearings can only withstand axial forces on one side, they need to be used in pairing applications. This type of bearing is used in gearboxes and axle boxes.
Four-point contact ball bearings are angular contact ball bearings. It can withstand axial loads in both directions and is typically paired with cylindrical roller bearings to withstand radial forces, with a radial clearance fit. The split structure of the inner ring allows it to assemble more steel balls. These bearings are used in gearboxes.
3. Cylindrical roller bearings
Single-row cylindrical roller bearings are more widely used in railway bearings than other bearings because the inner ring can be separated from the assembly composed of the outer ring, rollers and cage, which is extremely beneficial for the installation, disassembly, maintenance and inspection of the bearing. Cylindrical roller bearings are able to withstand high radial forces, and the corrected linear contact between the rolling elements and the raceway eliminates edge stresses, increasing the reliability of bearing applications. The combination of NJ and NUP cylindrical roller bearings can withstand a constant axial force. These bearings are used in traction motors, gearboxes, and wheelset hollow shaft drives.
4. Insulated bearings
Under some bad or special working conditions, the shaft bearing and motor bearing may be damaged due to additional voltage. Although the manufacturing process of the motor is perfect, it is not possible to completely avoid the potential difference between the rotor and stator due to electromagnetic asymmetry, so the current passes through the bearing and forms a closed circuit. In order to avoid the above situation, apply an oxide ceramic coating on the surface of the outer ring of the bearing to block the voltage not less than 1000V, and protect the bearing from the failure of the bearing due to electric erosion caused by additional voltage.
Post time: Feb-13-2025
