FIELD OF INVENTION;
The present invention relates to taper roller suspension bearing arrangement for
traction motor. The four traction motors of this type are used for hauling 25KV AC
EMU (Electric Multiple Unit) of Broad gauge Railways.
BACKGROUND OF INVENTION:
In the exiting art traction motor is fitted with two units of sleeve (journal) type
suspension bearings known as oil lubricated bearings. Oil for lubrication is filled in a
reservoir in an axle cap. The oil lubricates the bearings with the help of felt wick using
capillary method which results in spillage of excess oil through collar end of the
bearings. Therefore, oil gets consumed quickly. In this process, the availability of the
locomotive gets reduces. Also, journal bearings get worn out in due course of time and
have to be replaced. This drawback of the prior art is alleviated by the invention as
proposed.
All the above mentioned and other drawbacks of the prior art are alleviated by a taper
roller suspension bearing arrangement in traction motor as proposed in the present
invention.
OBJECTS OF INVENTION:
An object of the invention is to eliminate frequent refilling of the oil sump.
Another object of the invention is to eliminate frequent replacement of sleeve/ journal
bearings and wick pads of axle lubricators.
Yet another object of the invention is to increase the reliability of the suspension
bearing arrangement.
Yet another object of the invention is to provide a sealed bearing arrangement which
eliminates the ingress of dust and dirt from entering the bearings.

SUMMARY OF THE INVENTION:
In this invention the sleeve (journal) type axle bearings are replaced by Taper roller
suspension bearings. Stator frame, gear wheel, gear case and end shield of the
Traction motor have been suitably modified to accommodate the Taper Roller bearing
arrangement.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Fig 1 shows motor suspension unit
Fig 2 shows axle roller suspension bearing arrangement
Fig 3 shows assembly of suspension tube and fan chamber with magnet frame
Fig 4 shows flow path for grease
DETAILED DESCRIPTION OF A PREFFERED EMBODIMENT OF THE INVENTION:
The following description of the preferred embodiment is merely exemplary in nature
and is no way intended to limit the invention, its application or usage. To provide
clarity, the same reference number shall be used in drawing to identify similar
elements.
Taper roller bearings are housed in suspension tube assembled with a traction motor
by usage of plurality of bolts. The suspension tube is a semi cylinder components,
with two cylinder flanges for bearing housing at both ends called GWE (Gear Wheel
end) and RWE (Road wheel end).
Fig 1 shows the motor suspension unit. Fig 2 shows axle roller suspension bearing
arrangement and Fig 3 shows assembly of suspension tube and fan chamber with
magnet frame.
The axle suspension tube (7) is made out of cast steel and is of one of the integral part
and placed at the both ends to form cylinder bearing housings. The suspension tube is
designed with extended portion from the mounting location of flanges on suspension
tube and, magnet frame for providing sufficient space for fitment of fan assembly and
fan chamber. At the opening side of the U-type section of the suspension tube (7),
there is a machined flange which serves as the mounting surface to the magnet frame.
The upper flange of the suspension tube (7) is mounted to the magnet frame by means
of plurality of head bolts. The lower flange of the suspension tube is mounted in a slot

provided in the magnet frame and is secured by means of plurality of head bolts. The
hex head bolts are tightened with spring washers and the heads of the bolts are locked
by using means. Taper roller bearings (5) and (8) are used at both sides of tube. The
outer race of gear side bearing (8) is fitted directly into the bearing housing of
suspension tube, whereas the outer race of the opposite-side bearing (5) is fitted in to
separate cartridge bearing housing (3) for adjusting the axial distance. The inner races
of the both gear and opposite-side bearings are fitted to the axle. Adjustment of the
axial distance is accomplished by varying the thickness of split-type adjustment
washer (4). The split-type adjustment washers (4) are locked between the flange of
suspension tube and bearing housings. The suspension bearings (5) and (8) are
lubricated with greases. Grease is supplied through a grease orifice (6) fitted to the
suspension tube (7) by a grease pump.
Fig 4 shows flow path for grease. In the arrangement, the passage for filing of grease is
provided for re-lubrication of the taper roller bearings. The re-lubrication of the taper
roller bearings can be carried out without dismantling of the traction motor.
MAGNET FRAME:
The magnet frame is of high permeability cast steel. The magnet frame is accurately
machined to ensure the alignment of the end-shields, pole bores and axle way recess.
The nose of the motor is supported in the bogie with resilient rubber-steel sandwich
mounting.
The end shields are spigoted into the frame with slight interference fit and held in
position by means of bolts suitably locked. This method of mounting ensures that the
fit between the end shield and the frame can withstand the heavy jerks and vibration
from the railway tracks and remains tight in service. Roller bearings are provided and
labyrinths are formed to prevent the escape of lubricating grease or entry of dirt or
moisture. The frame is modified on the axle way side to accommodate the flanges of
the suspension tube, since complete assembly of motor with gear and pinion, and
suspension tube assembly is to be accommodated on the locomotive axle within the
two road wheel hubs of the locomotive.
ARMATURE:
The varnish coated electrical grade sheet steel punching are assembled with
interference fit directly on the shaft, which is made form nickel-chromium
molybdenum steel. The core is clamped between the end plated and rows of ventilation
ducts are provided effective cooling. The effective cooling is of arch-bound
construction. The copper segments are made of silver bearing copper segments. The
riser coupled with the bars, is slotted to receive armatures coil leads. Equalizers are
mounted at the commutator end of the armature. The armature coils are held down in
the core slot by epoxy glass wedges. Armature coil leads and equalizer leads are TIG

welded to commutator riser. Res-i-glass tape is used to retain the end windings.
Solvent-less polyester resin is used for VPI of the armature. The armature is
dynamically balanced. Poly tetra fluoro ethylene (PTFE) bush on steel vee ring and
arcing horns are provided to minimize the damage in the event of flash over.
BRUSH GEAR ASSEMBLY:
Split carbon brushes with rubber top and single spring brush holder are used for
better performance. Brush holder are secured to the magnet frame by fibre reinforced
plastic (FRP) molded insulated pins. A Poly tetra fluoro ethylene (PTFE) insulator
mounted on the support pin provides a creepage surface which easy to clean.
The radial distance of the brush holder from the commutator and brush spring
tensions can be adjusted. Arcing horns are provided to minimize the damage in the
event of flash over.
POLE AND FIELD COIL ASSEMBLIES:
The main poles are built form sheet steel lamination riveted together, whereas inter
poles are built from varnished coated electrical grade sheet steel lamination and
riveted together. The mail pole coils are with copper strap on flat, whereas the inter
pole coils are edge wound. The coils are insulated and bounded to poles with epoxy for
better thermal conduction. The mail pole and inter pole assemblies are rigidly bolted
to magnet frame. The bolt heads are sealed with a compound to prevent moisture
entry. All the internal connecting cables and connectors are effectively secured to
prevent movement and loosening of the connections.
ARMATURE BEARING ASSEMBLY:
The armature is supported on two grease-lubricated roller bearings. The bearing on
the commutator end acts as locating bearing while the pinion end bearing takes care
of any differential expansion between the armature frames. Both the bearing
arrangements are fully sealed there by necessitating lubrication only once in three
years or so. The sealed bearing arrangement also prevents bearing lubricator passing
into the machine or being contaminated with gear lubricant or other foreign material.
GEAR, PINION AND GEAR CASE:
The transmission consists of single reduction gear unit. The pinion is shrink fitted on
to the motor armature shaft, and the gear wheel is mounted directly on the Loco axle.
The gears are housed in a gear case, which is made in two halves. The half is attached
to the motor and the bottom half is bolted to the top half. A support arm is provided
on the end shield for better load sharing/ rigidly of the mounting. The joint between
the halves has an overlap and felt wipers are also provided to prevent contamination of
gear lubricant with dirt and moisture.

TAPER ROLLER SUSPENSION BEARINGS:
The traction motor is suspended on axle with taper roller suspension bearings. The
taper roller bearings are properly housed in the suspension tube assembly which is
bolted to the magnet frame.
With the successful DEVELOPMENT OF NOVEL DESIGN OF ROLLER SUSPENSION
BEARING ARRANGEMENT IN TM4601 TRACTION MOTOR FOR 25KV AC EMU
APPLICATION, Indian Railways will increase the locomotive availability for haulage as
re-lubrication is required only after six months vis-a-vis ever month earlier with sleeve
bearings.
This invention is described in detailed with the best modes to carry out the invention.
It is intended to include any sort of modification that may occur to any person skilled
in the art so as they come within the scope of the invention.

WE CLAIM:
1. An improved bearing arrangement for an electric machine that finds application
in traction, comprising:
a housing what includes plurality of taper roller bearing (5, 8) coupled to a
suspension tube that is coupled to the said electric machine;
wherein the suspended tube (7) comprises
at least an upper flange mounted on a magnet frame;
at least a lower flange fitted into a slot of the magnet frame;
wherein a portion of the suspension tube is extended to accommodate a cooling
assembly;
wherein an outer race of the taper roller bearing (8) is coupled to the
suspension tube (7) at one end;
wherein an outer race of the taper roller bearing (5) is coupled to an adjustable
cartridge bearing of other end;
wherein inner races of the plurality of taper roller bearing is coupled to an axle;
a grease orifice (6) coupled to the suspension tube aided by a grease pump.
2. An improved bearing arrangement as claimed in claim 1, wherein the adjustable
cartridge bearing adjusts the axial distance by varying thickness of a split type
adjustment washer (4).
3. An improved bearing arrangement as claimed in claim 2, wherein the split type
adjustment washer (4) is disposed between the suspension tube (7) and the
plurality of taper roller bearing.

4. An improved bearing arrangement as claimed in claim 1, wherein the
suspension tube (7) is a semi cylindrical component that includes plurality of
cylindrical flanges for the plurality of bearings at the ends.
5. An improved bearing arrangement as claimed in claim 1, wherein the electric
machine may be a motor.