FIELD OF INVENTION
The invention relates to an arrangement of improved bearing assembly with
provision of oil seal in 3 phase traction motor for broad gauge electric
locomotive.
BACKGROUND OF INVENTION
As per the existing drive end bearing assembly arrangement of 3-phase traction
motor for broad gauge diesel electric locomotives (ref. fig. 1), the lubrication of
drive end bearing is done by oil that is also used for lubrication of gear, pinion
available in gearbox. Oil for lubrication is circulated through the gearbox onto the
oil tray provided in the outer bearing cap (1). Oil enters the bearing (2) through
the gap provided between outer bearing cap (1) and bearing retaining collar (3).
After lubrication of drive end bearing (2), oil is circulated back into the gear box
through labyrinth provided in the inner bearing cap (4) and hole provided in end
shield (5). When oil level in the gearbox goes below permissible limits than
refilling of oil is done.
Location of holes in components such as outer bearing cap (1), bearing retaining
collar (3) and end shield (5) is critical since matching of holes in different
components during assembly is important for proper smooth flow of lubricating
oil. The whole lubrication system is quite cumbersome which requires refilling of

oil in the gearbox on regular basis. Further problem of oil leakage inside the
traction motor has been reported in quite a few motors resulting in failure of
motors. This is because geometry of components such as outer bearing cap (1),
inner bearing cap (4) and end shield (5) is quite intricate and minor deviation in
their dimensions w.r.t drawing dimensions may result in oil leakage inside
traction motor. Due to failure of traction motors, downtime of locomotive is
increased.

Therefore requirement of bearing assembly arrangement in which lubrication of
drive end bearing is done with grease was being felt which could overcome the
limitations of existing oil lubricated bearing system. For this, proper bearing
sealing is to be provided to prevent the entry of oil used for lubrication of gear,
pinion inside the traction motor.

OBJECTS OF THE INVENTION
Therefore, it is an object of the invention to propose an arrangement of
improved bearing assembly with provision of oil seal in 3 phase traction motor
for broad gauge electric locomotive which is capable of grease lubrication of
drive end bearing.
Another object of the invention is to propose an arrangement of improved
bearing assembly with provision of oil seal in 3 phase traction motor for broad
gauge electric locomotive which is able to eliminate the failures of the motors on
account of oil leakage inside the traction motors.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Fig.l - Shows the bearing assembly arrangement of the drive end of 3-
phase traction motor with oil lubrication of bearing as in prior arts.
Fig.2 - Shows the new bearing assembly arrangement having provision of
oil seal according to the present invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
In this invention, the existing drive end bearing assembly arrangement which is
suitable for oil lubrication of the drive end bearing of the 3-phase traction motor
for broad gauge diesel electric locomotives has been modified to the bearing
assembly arrangement having provision of oil seal and is suitable for grease
lubrication of the drive end bearing.
In this new bearing assembly arrangement (ref. fig.2), outer bearing cap (1) &
bearing retaining collar (2) have been modified and oil seal (3) is introduced in
the arrangement. Oil seal (3) acts as a sealing and prevent the lubricating oil of
gear, pinion available in gearbox from entering inside the traction motor.
Lubrication of drive end bearing is done with grease and of gear, pinion with oil
available in gearbox. In view of the high bearing temperature prevailing during
service, special grease which can retain its properties up to very high
temperatures has been used for lubrication of drive end bearing. Oil seal (3) is
fitted on the outer bearing cap (1) which acts as a sealing and prevent the
lubricating oil of gear, pinion from entering inside the traction motor. After final
motor assembly, there is no need of any bearing lubrication till 6 months and

after 6 months top up of grease at an interval 6 months of till periodic over
hauling of motor is done. Fresh grease is available in the groove of outer bearing
cap (1) above bearing retaining collar (2). Waste grease gets accumulated in the
groove of inner bearing cap (5) above shaft (7). Grease is completely cleaned
during periodic over hauling of traction motor and fresh greasing is done which is
followed by top up of grease at an interval 6 months till next periodic over
hauling.



With the successful development of this new bearing assembly arrangement for
drive end of 3-phase traction motor for broad gauge diesel electric locomotives,
re-lubrication of the drive end bearing shall be required only after 6 months and
maintenance work load of Railways shall be reduced. Further, problem of oil
leakage shall be avoided with this new arrangement because of provision of oil
seal which will prevent the oil to enter inside the motor.

WE CLAIM
1. An arrangement of improved bearing assembly with provisions of oil seal
in 3 phase traction motor for broad gauge diesel electric locomotive, the
said arrangement comprising;
lubricating the bearing (16) of drive end of the motor with grease;
fixing the bearing (16) in the drive end of the assembly; wherein,
a oil seal (13) is fitted on the outer bearing cap (11) to act as a
sealing to prevent the lubricating oil of gear, pinion from entering inside
the traction motor.
2. An arrangement as claimed in claim 1, wherein waste grease is
accumulated in the groove of inner bearing cap (15) above shaft (17).
3. An arrangement as claimed in claim 1, wherein fresh grease is disposed in
the groove of outer bearing cap (11) above bearing retaining collar (12).
4. An arrangement as claimed in claim 1, wherein process of cleaning the
grease, fresh greasing followed by top up of grease is carried out during
periodic over hauling of traction motor.

ABSTRACT

The invention relates to an arrangement of improved bearing assembly with
provision of oil seal in 3 phase traction motor. The arrangement comprises of
lubricating the drive end bearing (16) of the motor with grease, fixing the
bearing (16) in the drive end of the assembly when a oil seal (13) is fitted on the
outer bearing cap (11) to act as a sealing to prevent the lubricating oil of gear,
pinion from entering inside the traction motor.