Final drives

Final drives are built into the motor bogies of rail vehicles . They transmit and convert the torque and the speed of the drive motor to the wheelset shaft . The drive torque is supported by the torque arm on the bogie. Usually final drives have a so-called emergency catch or emergency support. This prevents the gear unit from falling into the track bed if the torque arm breaks . Housings are made of nodular cast iron (example: Vossloh G 6 ) or cast aluminum (example: HHA type DT5 ). Nowadays, labyrinth seals are used almost exclusively . Conventional splash lubrication is usually sufficient , in special cases oil pumps are used (example: Siemens Ultra Low Floor ). In the case of final drives for high-speed multiple units, the bearing temperatures are permanently monitored.

Construction variants

Final drives are mostly:

• 1-stage (example: Metrowagonmasch 81-740 / 741 )
• 1-stage with intermediate gear (example: Treno Alta Frequentazione ), or
• 2-stage (example: Siemens Desiro, NMBS / SNCB series AM 08 ).

Depending on the arrangement of the drive, spur gears , bevel gears or a combination of both are used.

One also differentiates:

• fully sprung (example: Eurotunnel Class 9 ),
• partially sprung (example: CRH3 ) and
• unsprung final drive (see also drive in the center bearing )

Connection of drive to gearbox (with DMU) or electric motor :

• Via cardan shaft (example: SNCF Z-TER )
• Drive coupling, e.g. B. Curved tooth coupling for travel compensation between wheelset and bogie
• firmly locked with or without rubber elements (example: DB series 423 )

Connection output:

• Gear (crown wheel) is pressed directly onto the wheelset shaft (example: Alstom Coradia LINT )
• via hollow shaft (example: Metro Madrid , series 7000)
• via wedge pack coupling (example: WSW generation 15 )
• Handlebar coupling

If the direction of travel can be changed in the final drive, it is referred to as a reverse drive. Some final drives have a "through drive" which makes it possible to drive the second axle in the same bogie via a cardan shaft.

literature

• Christian Schindler (Ed.): MANUAL Rail Vehicles: Development - Production - Maintenance , ISBN 978-3-7771-0427-0
• Karl Gerhard Bauer: Bogies - Bogies , ISBN 9783882551471