“A SEALING ARRANGEMENT IN THREE-PHASE INDUCTION
TRACTION MOTOR FOR AC LOCO”
[001]
FIELD OF INVENTION
01] The present subject matter described herein, relates to a sealing
arrangement in a three phase-phase induction traction motor for AC loco. More
particularly, to a sealing arrangement to avoid mixing of lubricating bearing
grease with gearbox oil in a three phase-phase induction traction motor for AC
loco.
[002]
BACKGROUND AND PRIOR ART AND PROBLEM IN PRIOR ART
02] As per the existing arrangement, as illustrated in Figure 1 of, 3-phase
[003]
induction traction motor for AC loco, the lubrication of drive end bearing is done
by lubricating grease. Drive end (DE) of the motor shaft (003) projects beyond
bearing and pinion (002) is mounted on it. Pinion drives the gear (006) mounted
on the axle of loco. Gear (006) and pinion (002) are enclosed in the gear box
(001). Lubrication of gear (006) and pinion are done with oil available in gear box
(001) through splash lubrication. Teeth of gear (006) are partially dipped Inside
the oil and when the gear operates, this oil is passed on the teeths of the gear (006)
and pinions (002) thus providing an effective lubrication of the gear and pinion.
03] Oil for lubrication of gear (006), pinion (002) available in gearbox (001)
must not mix with grease in bearing thus sealing arrangement shall be such that it
prevents mixing of gear oil with bearing grease. The bearing used in traction
motor are of large diameter and speed of traction motor are also high thus high
peripheral speed and compact space are area of concern for sealing arrangement.
In existing prior art for such type of application static retaining bearing cap (005)
and rotating disc (004) are being used which have multiple projection in static
retaining bearing cap and rotating disc. Static retaining bearing cap and rotating
disc have minimum operational clearance between static and rotating parts from
where sometimes oil leakage may occur resulting in mixing of gearbox oil with
the bearing grease. Mixing of gear box lubricating oil and bearing grease lead to
change in properties of bearing grease. This results into low viscosity and washing

away of grease from bearing assembly. Insufficient lubrication of the bearing
results into seizure and damage of bearing.
[004] To address such issues a new sealing arrangement is required. As this
arrangement is being used for AC loco, due to space constraint of mounting of
motors between wheels in loco, the arrangement requires to be designed in
existing space envelope.
[005] Table 1: Illustration of existing oil sealing arrangement at Drive End
(DE) side of 3-phase Induction traction motor for AC loco.
Reference Description (Figure 1)
no.
1 Gear Box
2 Pinion
3 Shaft
4 Rotating disc
5 Static bearing retaining cap
6 Gear
OBJECTS OF THE INVENTION
[006] It is therefore the object of the invention to overcome the aforementioned
and other drawbacks in prior art.
[007] The principal objective of the present invention is to provide for a sealing
arrangement to avoid mixing of lubricating bearing grease with gearbox oil in 3-
phase induction traction motor for AC loco.
[008] Another object of the present invention is to provide for an arrangement
having positive contacts between rotating and static components to completely
eliminate the possibility of leakage of oil/intermixing of oil with grease.
[009] These and other objects and advantages of the present subject matter
would be apparent to a person skilled in the art after consideration of the
following detailed description taken into consideration with accompanying
drawings in which preferred embodiments of the present subject matter are
illustrated.

SUMMARY OF THE INVENTION
[0010] One or more drawbacks of the conventional technology based on existing
sealing arrangements are overcome, and additional advantages are provided
through a novel sealing arrangement to avoid mixing of lubricating bearing grease
with gearbox oil in 3-phase induction traction motor for AC loco. The present
sealing arrangement provides for positive contacts between rotating and static
components thus completely eliminating the possibility of leakage of
oil/intermixing of oil with grease. Additional features and advantages are realized
through the technicalities of the present disclosure. Other embodiments and
aspects of the disclosure are described in detail herein and are considered to be a
part of the claimed disclosure.
[0011] In an embodiment of the present subject matter, a sealing arrangement to
avoid mixing of lubricating bearing grease with gearbox oil in a three phase-phase
induction traction motor for AC loco, the arrangement comprises a gear box, a
pinion, a shaft, a rotating disc, a static bearing retaining cap, a gear, a double lip
spring loaded ring and an inner wiper, wherein the static bearing retaining cap has
a tapered inner surface at oil inlet, a cutout at bottom side for oil drainage, a
projection in axial direction to allow limited quantity of oil for lubrication of
double lip spring loaded ring, a groove at inner surface for effective oil drainage
and stepped structure for fitment of double lip spring loaded ring.
[0012] In another embodiment of the present subject matter, the rotating disc
having modified radial projection to suit taper in inner surface of static bearing
retaining cap.
[0013] In another embodiment of the present subject matter, the stepped structure
is in axial direction.
[0014] In another embodiment of the present subject matter, the inner wiper has a
stepped surface structure.
[0015] In another embodiment of the present subject matter, the lips of double lip
spring loaded ring are lubricated by grease at one side and by oil on other side.
[0016] It is to be understood that the aspects and embodiments of the disclosure
described above may be used in any combination with each other. Several of the

aspects and embodiments may be combined to form a further embodiment of the
disclosure.
[0017] The foregoing summary is illustrative only and is not intended to be in any
way limiting. In addition to the illustrative aspects, embodiments, and features
described above, further aspects, embodiments, and features will become apparent
by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] It is to be noted, however, that the appended drawings illustrate only
typical embodiments of the present subject matter, and are therefore not to be
considered for limiting of its scope, for the invention may admit to other equally
effective embodiments. The detailed description is described with reference to the
accompanying figures. In the figures, a reference number identifies the figure in
which the reference number first appears. The same numbers are used throughout
the figures to reference like features and components. Some embodiments of
system or methods or structure in accordance with embodiments of the present
subject matter are now described, by way of example, and with reference to the
accompanying figures, in which:
[0019] Figure 1 illustrates a schematic view of an existing oil sealing arrangement
at Drive End (DE) side of 3-phase Induction traction motor for AC loco;
[0020] Figure 2 illustrates a schematic view of the present sealing arrangement to
avoid mixing of lubricating bearing grease with gearbox oil in a three phase-phase
induction traction motor for AC loco in accordance with an embodiment of the
present disclosure;
[0021] The figures depict embodiments of the present subject matter for the
purposes of illustration only. A person skilled in the art will easily recognize from
the following description that alternative embodiments of the structures and
methods illustrated herein may be employed without departing from the principles
of the disclosure described herein.

DETAILED DESCRIPTION
[0022] The detailed description of various exemplary embodiments of the
disclosure is described herein with reference to the accompanying drawings. It
should be noted that the embodiments are described herein in such details as to
clearly communicate the disclosure. However, the amount of details provided
herein are not intended to limit the anticipated variations of embodiments; on the
contrary, the intention is to cover all modifications, equivalents, and alternatives
falling within the scope of the present disclosure as defined by the appended
claims.
[0023] It is also to be understood that various arrangements may be devised that,
although not explicitly described or shown herein, embody the principles of the
present disclosure. Moreover, all statements herein reciting principles, aspects,
and embodiments of the present disclosure, as well as specific examples, are
intended to encompass equivalents thereof.
[0024] The terminology used herein is for the purpose of describing particular
embodiments only and is not intended to be limiting of example embodiments. As
used herein, the singular forms “a",” “an” and “the” are intended to include the
plural forms as well, unless the context clearly indicates otherwise. It will be
further understood that the terms “comprises,” “comprising,” “includes” and/or
“including,” when used herein, specify the presence of stated features, integers,
steps, operations, elements and/or components, but do not preclude the presence
or addition of one or more other features, integers, steps, operations, elements,
components and/or groups thereof.
[0025] It should also be noted that in some alternative implementations, the
functions/acts noted may occur out of the order noted in the figures. For example,
two figures shown in succession may, in fact, be executed concurrently or may
sometimes be executed in the reverse order, depending upon the functionality/acts
involved.
[0026] Unless otherwise defined, all terms (including technical and scientific
terms) used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which example embodiments belong. It will be further

understood that terms, e.g., those defined in commonly used dictionaries, should
be interpreted as having a meaning that is consistent with their meaning in the
context of the relevant art and will not be interpreted in an idealized or overly
formal sense unless expressly so defined herein.
[0027] The present disclosure discloses an improved sealing arrangement to avoid
mixing of lubricating bearing grease with gearbox oil in a three phase-phase
induction traction motor for AC loco. The present arrangement leads to ease in
manufacturing of sealing arrangement. The present sealing is more effective in
providing a sealing between gear oil and grease. Therefore, there are reduced
number of bearing failures on account of mixing of oil with grease in accordance
with the present arrangement.
[0028] These and other advantages of the present subject matter would be
described in greater detail with reference to the following figures. It should be
noted that the description merely illustrates the principles of the present subject
matter. It will thus be appreciated that those skilled in the art will be able to devise
various arrangements that, although not explicitly described herein, embody the
principles of the present subject matter and are included within its scope.
[0029] As illustrated in Figure 2, a sealing arrangement to avoid mixing of
lubricating bearing grease with gearbox oil in a three phase-phase induction
traction motor for AC loco. The arrangement comprises a gear box 201, a pinion
202, a shaft 203, a rotating disc 204, a static bearing retaining cap 205, a gear 206,
a double lip spring loaded ring 207 and an inner wiper 208, wherein the static
bearing retaining cap 205 has a tapered inner surface 209 at oil inlet, a cutout at
bottom side 210 for oil drainage, a projection in axial direction 211 to allow
limited quantity of oil for lubrication of double lip spring loaded ring 207, a
groove at inner surface 212 for effective oil drainage and stepped structure 213 for
fitment of double lip spring loaded ring 207.
[0030] Further, in the present sealing arrangement the rotating disc 204 having
modified radial projection 214 to suit taper in inner surface 209 of static bearing
retaining cap 205. The stepped structure 215 of rotating disc (204) in axial
direction to allow limited quantity of oil to spring loaded oil ring (207) and the

inner wiper 208 has a stepped surface 216 structure for providing additional
barrier to prevent mixing of oil & grease. The lips of double lip spring loaded
ring 207 are lubricated by grease at one side and by oil on other side.
[0031] It will be understood by those within the art that, in general, terms used
herein, and especially in the appended claims (e.g., bodies of the appended
claims) are generally intended as “open” terms (e.g., the term “including” should
be interpreted as “including but not limited to,” the term “having” should be
interpreted as “having at least,” the term “includes” should be interpreted as
“includes but is not limited to,” etc.). It will be further understood by those within
the art that if a specific number of an introduced claim recitation is intended, such
an intent will be explicitly recited in the claim, and in the absence of such
recitation no such intent is present. For example, as an aid to understanding, the
following appended claims may contain usage of the introductory phrases “at least
one” and “one or more” to introduce claim recitations. However, the use of such
phrases should not be construed to imply that the introduction of a claim recitation
by the indefinite articles “a” or “an” limits any particular claim containing such
introduced claim recitation to inventions containing only one such recitation, even
when the same claim includes the introductory phrases “one or more” or “at least
one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should
typically be interpreted to mean “at least one” or “one or more”); the same holds
true for the use of definite articles used to introduce claim recitations. In addition,
even if a specific number of an introduced claim recitation is explicitly recited,
those skilled in the art will recognize that such recitation should typically be
interpreted to mean at least the recited number (e.g., the bare recitation of “two
recitations,” without other modifiers, typically means at least two recitations, or
two or more recitations). It will be further understood by those within the art that
virtually any disjunctive word and/or phrase presenting two or more alternative
terms, whether in the description, claims, or drawings, should be understood to
contemplate the possibilities of including one of the terms, either of the terms, or
both terms. For example, the phrase “A or B” will be understood to include the
possibilities of “A” or “B” or “A and B.”

[0032] It will be further appreciated that functions or structures of a plurality of
components or steps may be combined into a single component or step, or the
functions or structures of one-step or component may be split among plural steps
or components. The present invention contemplates all of these combinations.
Unless stated otherwise, dimensions and geometries of the various structures
depicted herein are not intended to be restrictive of the invention, and other
dimensions or geometries are possible. In addition, while a feature of the present
invention may have been described in the context of only one of the illustrated
embodiments, such feature may be combined with one or more other features of
other embodiments, for any given application. It will also be appreciated from the
above that the fabrication of the unique structures herein and the operation thereof
also constitute methods in accordance with the present invention. The present
invention also encompasses intermediate and end products resulting from the
practice of the methods herein. The use of “comprising” or “including” also
contemplates embodiments that “consist essentially of” or “consist of” the recited
feature.
[0033] Although embodiments for the present subject matter have been described
in language specific to structural features, it is to be understood that the present
subject matter is not necessarily limited to the specific features described. Rather,
the specific features and methods are disclosed as embodiments for the present
subject matter. Numerous modifications and adaptations of the system/component
of the present invention will be apparent to those skilled in the art, and thus it is
intended by the appended claims to cover all such modifications and adaptations,
which fall within the scope of the present subject matter.
[0034] Reference Numerals:
Reference Description
Numerals
201 Gear box

202 pinion
203 Shaft
204 Rotating disc
205 static bearing retaining cap
206 gear
207 double lip spring loaded ring
208 Inner wiper
209 tapered inner surface at oil inlet
210 cutout at bottom side for oil drainage
211 projection in axial direction
212 groove at inner surface
213 stepped structure
214 radial projection
215 Step in axial direction
216 stepped surface of inner wiper

We Claim:
1. A sealing arrangement to avoid mixing of lubricating bearing grease with
gearbox oil in a three phase-phase induction traction motor for AC loco, the
arrangement comprises:
a gear box (201);
a pinion (202);
a shaft (203)
a rotating disc (204);
a static bearing retaining cap (205);
a gear (206);
characterized in that,
a double lip spring loaded ring (207); and
an inner wiper (208),
wherein the static bearing retaining cap (205) has a tapered inner surface (209) at
oil inlet, a cutout at bottom side (210) for oil drainage, a projection in axial
direction (211) to allow limited quantity of oil for lubrication of double lip spring
loaded ring (207), a groove at inner surface (212) for effective oil drainage and
stepped structure (213) for fitment of double lip spring loaded ring (207).
2. The sealing arrangement as claimed in claim 1, wherein the rotating disc
(204) having modified radial projection (214) to suit taper in inner surface (209)
of static bearing retaining cap (205).
3. The sealing arrangement as claimed in claim 1, wherein the stepped
structure (215) of rotating disc (204) in axial direction.
4. The sealing arrangement as claimed in claim 1, wherein the inner wiper
(208) has a stepped surface (216) structure.

5. The sealing arrangement as claimed in claim 1, wherein the lips of double lip
spring loaded ring (207) are lubricated by grease at one side and by oil on other
side.