Note: Descriptions are shown in the official language in which they were submitted.
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Title: ELECTRIC SUBMERSIBLE MOTOR THRUST BEARING SYSTEM
BACKGROUND
1. FIELD OF THE INVENTION
Embodiments of the invention described herein pertain to the field of electric
submersible pumps. More particularly, but not by way of limitation, one or
more embodiments
of the invention enable an electric submersible motor thrust bearing system.
2. DESCRIPTION OF THE RELATED ART
Fluid, such as natural gas, oil or water, is often located in underground
formations.
When pressure within the well is not enough to force fluid out of the well,
the fluid must be
pumped to the surface so that it can be collected, separated, refined,
distributed and/or sold.
Centrifugal pumps are typically used in electric submersible pump (ESP)
applications for
lifting well fluid to the surface. Centrifugal pumps impart energy to a fluid
by accelerating the
fluid through a rotating impeller paired with a stationary diffuser. A
rotating shaft runs through
the central hub of the impeller, and the impeller is keyed to the shaft such
that the impeller
rotates with the shaft. An electric motor below the pump turns the shaft.
The electric motor is typically a two-pole, three-phase squirrel cage
induction motor.
The head of the motor includes a thrust bearing near the top of the motor. The
thrust bearing
holds the weight of the motor's rotor and shaft hanging below the motor head,
which can be
between 50 ¨ 2,000 pounds, depending on the size and length of the motor.
Conventionally, motor thrust bearing sets are hydrodynamic and include a
thrust runner
that rotates with the shaft opposite a thrust bearing that does not rotate.
Above the thrust runner
is a lock ring that is bolted to the top of thrust runner and rotates with the
thrust runner. A split
ring is seated in a groove around the motor shaft inside the lock ring. The
split ring, secured
within the shaft groove, is meant to prevent the thrust bearing assembly from
sliding axially
along the motor shaft. The lock ring is typically bolted to the thrust runner,
and in this manner,
held in place around the split ring. When bolted in place, the lock ring
prevents the split ring
from expanding radially out of the shaft groove, keeping the split ring from
popping out of the
groove and holding the split ring axially in place on the motor shaft.
A problem that arises is that during operation of the electric submersible
motor, the
bolts that secure the lock ring to the thrust runner back out and sheer,
loosening the lock ring's
hold on the split ring. When the lock ring disengages, the split ring radially
expands and then
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move axially along the motor shaft during operation of the ESP motor. Movement
of the split
ring can cause the motor shaft to drop through and fall out of the motor,
causing complete
motor failure.
As is apparent from the above, current thrust bearings for electric
submersible motors
suffer from axial movement and loss of the motor shaft. Therefore, there is a
need for an
improved electric submersible motor thrust bearing system.
SUMMARY
One or more embodiments of the invention enable an electric submersible motor
thrust
bearing system.
An electric submersible motor thrust bearing system is described. An
illustrative
embodiment of an electric submersible motor thrust bearing system includes a
thrust bearing
assembly carrying a thrust of an electric submersible motor, the thrust
bearing assembly
including a split ring secured around a shaft of the electric submersible
motor inward of a
rotatable thrust runner, the rotatable thrust runner coupled around an outer
diameter of the split
ring and mated above a non-rotatable thrust bearing, the rotatable thrust
runner serving as a
barrier to radial expansion of the split ring, a lock ring secured to the
thrust runner by a threaded
connection, at least a portion of the lock ring above the split ring and at
least a portion of the
thrust runner below the split ring, and the threaded connection securing the
split ring axially
between the lock ring and the thrust runner. In some embodiments, a base of
the rotatable thrust
runner is keyed to the shaft below the split ring such that the thrust runner
rotates with the shaft,
the non-rotatable thrust bearing secured to a housing of a head of the
electric submersible
motor. In certain embodiments, a series of bronze pads extend around the non-
rotatable thrust
bearing between the non-rotatable thrust bearing and the rotatable thrust
runner. In some
embodiments, the threaded connection further includes a tubular extension
extending upwards
from a base of the rotatable thrust runner, the tubular extension having male
threads around an
outer diameter of the tubular extension, the lock ring having female threads
around an inner
diameter of the lock ring, and the male and female threads mated such that
rotation of the shaft
tightens the threaded connection. In certain embodiments, the tubular
extension surrounds the
outer diameter of the split ring and the lock ring surrounds the outer
diameter of the tubular
extension. In some embodiments, the lock ring further includes a top surface
extending above
the threaded connection and radially between the vertical motor shaft and the
outer diameter of
the lock ring. In certain embodiments, the top surface serves as a barrier to
upward axial
movement of the split ring. In certain embodiments, a space extends between
the split ring and
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the top surface. In some embodiments. the threaded connection further includes
a tubular
extension extending upwards from a base of the rotatable thrust runner, the
tubular extension
having female threads around an inner diameter of the tubular extension, the
lock ring having
male threads around an outer diameter of the lock ring, and the male and
female threads mated
such that rotation of the shaft tightens the threaded connection. In certain
embodiments, the
lock ring surrounds an outer diameter of the split ring, and the tubular
extension surrounds the
outer diameter of the lock ring. In some embodiments, the lock ring further
includes a shoulder
that sandwiches the split ring between the shoulder and a base of the
rotatable thrust runner. In
certain embodiments, a portion of the lock ring below the shoulder extends
around an outer
diameter of the split ring. In some embodiments, a plurality of set screws
extend axially through
the lock ring and engage the thrust runner.
An illustrative embodiment of an electric submersible motor thrust bearing
system
includes an electric submersible motor operatively coupled to an electric
submersible pump, a
head of the electric submersible motor supporting a rotatable motor shaft
extending below the
.. head, the head including a thrust bearing set including a rotatable thrust
runner keyed to the
motor shaft opposite a non-rotatable thrust bearing below the thrust runner,
the rotatable thrust
runner including a base mateable with a series of pads on the non-rotatable
thrust bearing, and
a tubular extension extending upwards from the base, the tubular extension
including a first set
of threads, a rotatable lock ring secured one of inside or around the tubular
extension, the
rotatable lock ring including a second set of threads mated to the first set
of threads to form a
threaded connection, the threaded connection tightened in a direction of
rotation of the motor
shaft, and a split ring seated in a groove on the motor shaft inward of the
tubular extension of
the rotatable thrust runner, the split ring above the base and below at least
a portion of the
rotatable lock ring. In some embodiments, a plurality of set screws extend
axially through the
lock ring and engage the thrust runner. In some embodiments, the lock ring
further includes a
shoulder that extends above the split ring sandwiching the split ring between
the shoulder and
the base of the thrust runner. In certain embodiments, the rotatable lock ring
is secured inside
the tubular extension and around the motor shaft, and wherein the first set of
threads are female
threads and the second set of threads are male threads. In some embodiments.
the lock ring
surrounds the split ring and the tubular extension of the rotatable thrust
runner surrounds the
lock ring. In certain embodiments, the tubular extension surrounds the split
ring, the rotatable
lock ring is secured around the tubular extension, and the first set of
threads are male threads
and the second set of threads are female threads. In some embodiments, the
lock ring further
includes engagement apertures on a top of the lock ring, the engagement
apertures permitting
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rotational engagement of the threaded connection. In certain embodiments, the
base serves as
a barrier to downward axial movement of the split ring and the lock ring
serves as a barrier to
upward axial movement of the split ring. In some embodiments, the non-
rotatable thrust
bearing is secured against rotation by a pin engaging a housing of the head.
In certain
embodiments, the rotatable thrust runner surrounds the split ring and serves
as a barrier to radial
expansion of the split ring.
An illustrative embodiment of an electric submersible motor thrust bearing
system
includes a thrust bearing assembly carrying a thrust of an electric
submersible motor, the thrust
bearing assembly including a split ring secured around a shaft of the electric
submersible motor
inward of a rotatable thrust runner, the rotatable thrust runner coupled
around an outer diameter
of the split ring and mated above a non-rotatable thrust bearing, the
rotatable thrust runner
serving as a barrier to radial expansion of the split ring, a lock ring
secured within a recess in
the thrust runner, at least a portion of the lock ring above the split ring
and at least a portion of
the thrust runner below the split ring, and a snap ring securing the split
ring axially between
the lock ring and the thrust runner. In some embodiments, the rotatable thrust
runner includes
a tubular extension above a base, the tubular extension forming the recess and
including a snap
ring groove, the snap ring partially seated in the snap ring groove and
partially extending above
the lock ring. In certain embodiments, the lock ring surrounds the split ring,
and the tubular
extension surrounds the lock ring.
In further embodiments, features from specific embodiments may be combined
with
features from other embodiments. For example, features from one embodiment may
be
combined with features from any of the other embodiments. In further
embodiments,
additional features may be added to the specific embodiments described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
Advantages of the present invention may become apparent to those skilled in
the art
with the benefit of the following detailed description and upon reference to
the accompanying
drawings in which:
FIG. 1 is a perspective view of an electric submersible pump assembly of an
illustrative
embodiment.
FIG. 2 is a perspective view of a motor head of an illustrative embodiment.
FIG. 3 is a perspective view of a thrust bearing assembly of an illustrative
embodiment.
FIG. 4 is a cross-sectional perspective view of a thrust bearing assembly of
an illustrative
embodiment.
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FIG. 5 is a perspective view of a thrust bearing assembly of an illustrative
embodiment.
FIG. 6 is an exploded view of a thrust bearing assembly of an illustrative
embodiment.
FIGs. 7-8 are a perspective views of a motor head of an illustrative
embodiment.
FIG. 9 is a cross-sectional perspective view of a motor head of an
illustrative embodiment.
FIG. 10 is an exploded view of a thrust bearing assembly of an illustrative
embodiment.
FIGs. 11-12 are perspective views of a thrust bearing assembly of an
illustrative embodiment.
FIG. 13 is a cross-sectional perspective view of a thrust bearing assembly of
an illustrative
embodiment.
FIG. 14 is an exploded view of a thrust bearing assembly of an illustrative
embodiment.
While the invention is susceptible to various modifications and alternative
forms,
specific embodiments thereof are shown by way of example in the drawings and
may herein
be described in detail. The drawings may not be to scale. It should be
understood, however,
that the embodiments described herein and shown in the drawings are not
intended to limit the
invention to the particular form disclosed, but on the contrary, the intention
is to cover all
modifications, equivalents and alternatives falling within the scope of the
present invention as
defined by the appended claims.
DETAILED DESCRIPTION
An electric submersible motor thrust bearing system is described. In the
following
exemplary description, numerous specific details are set forth in order to
provide a more
thorough understanding of embodiments of the invention. It will be apparent,
however, to an
artisan of ordinary skill that the present invention may be practiced without
incorporating all
aspects of the specific details described herein. In other instances, specific
features, quantities,
or measurements well known to those of ordinary skill in the art have not been
described in
detail so as not to obscure the invention. Readers should note that although
examples of the
invention are set forth herein, the claims, and the full scope of any
equivalents, are what define
the metes and bounds of the invention.
As used in this specification and the appended claims, the singular forms "a",
"an" and
"the" include plural referents unless the context clearly dictates otherwise.
Thus, for example,
reference to a thread includes one or more threads.
As used in this specification and the appended claims, -coupled" refers to
either a direct
connection or an indirect connection (e.g., at least one intervening
connection) between one or
more objects or components. The phrase "directly attached" means a direct
connection
between objects or components.
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As used in this specification and the appended claims, "downstream" or
"upwards"
refer interchangeably to the longitudinal direction substantially with the
principal flow of lifted
fluid when the pump assembly is in operation. By way of example but not
limitation, in a
vertical downhole ESP assembly, the downstream direction may be towards the
surface of the
well. The "top" of an element refers to the downstream-most side of the
element, without regard
to whether the element is oriented horizontally, vertically or extends through
a radius. -Above"
refers to an element located further downstream than the element to which it
is compared.
As used in this specification and the appended claims, "upstream" or
"downwards"
refer interchangeably to the longitudinal direction substantially opposite the
principal flow of
lifted fluid when the pump assembly is in operation. By way of example but not
limitation, in
a vertical downhole ESP assembly, the upstream direction may be opposite the
surface of the
well. The "bottom" of an element refers to the upstream-most side of the
element, without
regard to whether the element is oriented horizontally, vertically or extends
through a radius.
"Below" refers to an element located further upstream than the element to
which it is compared.
As used herein, the term "outer," "outside" or "outward" mean the radial
direction away
from the center of the shaft of the electric submersible pump (ESP) assembly
component and/or
the opening of a component through which the shaft would extend. In the art,
the -outer
diameter" is used to refer to the outer circumference or outer surface of a
tube-shaped or annular
object, such as a bearing or ring.
As used herein, the term "inner", "inside" or "inward" means the radial
direction toward
the center of the shaft of the ESP assembly component and/or the opening of a
component
through which the shaft would extend. In the art, the "inner diameter" is used
to refer to the
inner circumference or inner surface of a tube-shaped or annular object, such
as a bearing or
ring.
As used herein the terms "axial", "axially", "longitudinal" and
"longitudinally" refer
interchangeably to the direction extending along the length of the shaft of
the ESP motor.
For ease of description, the illustrative embodiments described herein are
described in
terms of an electric submersible pump (ESP) assembly operating in a downhole
oil or gas well.
However, illustrative embodiments are not so limited and may be equally
applied to any
hydrodynamic thrust bearing secured around a rotatable shaft and carrying high
axial loads
(e.g., 2,000 pounds), where it is desirable to prevent axial movement of the
shaft.
Illustrative embodiments may prevent axial movement and loss of an ESP motor
shaft.
Illustrative embodiments may prevent a split ring, which holds a thrust
bearing assembly
axially in place on the motor shaft, from expanding radially out of its shaft
groove and then
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sliding axially along the motor shaft. Illustrative embodiments may secure the
split ring inward
of the thrust runner, and secure the lock ring to the thrust runner by thread
and/or snap ring,
eliminating problematic bolts that tend to back out and sheer. Illustrative
embodiments may
prevent the ESP motor shaft from dropping through and falling out of the
motor.
Illustrative embodiments include a thrust bearing assembly that carries thrust
of an
electric submersible motor. The thrust bearing assembly may include a lock
ring secured to a
thrust runner by a threaded connection and/or snap ring. The thrust runner may
surround a split
ring seated within a groove on the ESP motor shaft. The threaded connection
and/or snap ring
may capture the split ring radially inside the thrust runner, and axially
between the lock ring
and the thrust runner, preventing unseating and/or axial movement of the split
ring. The thrust
runner may include a tubular extension that extends upwards from a base of the
thrust runner,
the tubular extension may include male or female threads that mate with
threads on the lock
ring. The threaded connection may tighten in the direction of rotation of the
vertical motor
shaft.
FIG. 1 illustrates an ESP assembly including an electric submersible motor of
illustrative embodiments. ESP assembly 100 may be downhole in a well, such as
an oil or gas
well. ESP assembly 100 may be vertical and/or extend through a radius. In some
embodiments,
ESP assembly 100 may be horizontally arranged within the downhole well. ESP
assembly may
include electric motor 105. Electric submersible motor 105 may be a two-pole,
three-phase
squirrel cage induction motor that operates to turn the shaft of ESP pump 110.
ESP pump 110
may be a multi-stage centrifugal pump with stacked impeller and diffuser
stages. Seal section
115 may protect electric motor 105 from the ingress of well fluid and may
equalize pressure
inside motor 105. Intake 120 may serve as the intake for fluid to ESP pump
110. Production
tubing 125 may carry lifted fluid to the surface of the well. ESP motor head
130 may be bolted
to seal section 115, with the weight of the remainder of motor 105, including
the motor shaft
and rotor sections, hanging from head 130. Downhole sensors 135 may also hang
below motor
head 130. Motor head 130 may include a thrust bearing assembly to carry thrust
loads and a
power connection that receives ESP power cable 140 and/or a motor lead
extension. ESP power
cable 140 may obtain power from a surface power source inside cabinet 145.
Cabinet 145 may
also house a variable frequency drive (VFD) and/or VFD controller that
operates electric motor
105 by providing and/or varying input voltage and/or current to ESP motor 105.
FIG. 2 illustrates motor head 130 with a thrust bearing assembly of
illustrative
embodiments. Housing 200 of motor head 130 may be bolted to flanged adapter
205 that
connects motor head 130 to seal section 115. Head 130 may also include power
connection
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1100 (shown in FIG. 11) for connection of motor 105 to power cable 140 and/or
a motor lead
extension and/or power source. Motor shaft 210 may extend centrally and
longitudinally
through motor 105 and motor head 130, with the majority of the length of motor
shaft 210
extending below motor head 130. Motor shaft 210 may include splines 610 for
connection to
the shaft of seal section 115 above motor shaft 210, and motor shaft 210 may
be hollow to
allow motor oil to flow through motor shaft 210. Thrust bearing assembly 215
may be included
in motor head 130 and carry thrust loads, such as the weight of motor shaft
210, motor rotor
sections (not shown) and downhole sensors 135 all hanging below motor head
130. Thrust
bearing assembly 215 may be within motor head 130 and/or may extend partially
into adapter
205. Thrust bearing assembly 215 may include a hydrodynamic bearing set that
contains,
consists of and/or includes non-rotating thrust bearing 220 and rotatable
thrust runner 225.
Thrust bearing 220 may be seated on housing 200 of head 130 and/or pinned
against rotation
to housing 200 of head 130. Pin 330 may engage thrust bearing 220 and housing
200 and may
prevent rotation of thrust bearing 220. A series of bronze pads 230 may be
dispersed around
thrust bearing 220, between thrust bearing 220 and thrust runner 225. Thrust
bearing 220 and
thrust runner 225 may each be annular and surround shaft 210. Thrust runner
225 may be keyed
and/or secured to shaft 210 such that thrust runner rotates with shaft 210.
Motor oil provided
by an oil port in the hollow motor shaft 210 may lubricate the space between
thrust runner 225
and thrust bearing, allowing a hydrodynamic fluid film to form between thrust
bearing 220 and
thrust runner 225.
Turning to FIG. 3, lock ring 300 may be threaded to thrust runner 225. FIG. 3
illustrates
an embodiment where thrust runner 225 has female threads and lock ring 300 has
male threads.
Thrust runner 225 may include base 305 and tubular extension 310. Base 305 may
oppose
and/or mate with thrust bearing 220 and/or be adjacent to bronze pads 230.
Tubular extension
310 may extend upward above base 305, may be tubular and/or a hollow cylinder
and may
surround lock ring 300. The inner diameter of tubular extension 310 may
include runner threads
315, and the outer diameter of lock ring 300 may include lock ring threads
320. Runner threads
315 may receive lock ring threads 320 to form a threaded connection between
lock ring 300
and thrust runner 225. Threaded connection between runner threads 315 and lock
ring threads
320 may include fine threads and/or 5-7 threads of engagement. In some
embodiments,
threaded connection may be buttress threads. As shown in FIG. 3, when
threadedly engaged,
lock ring 300 may sit within and/or inside thrust runner 225 and/or tubular
extension 310, above
base 305 of thrust runner 225. Thrust runner 225 and/or lock ring may be
machined and/or
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formed from high strength stainless steel. Radial bearing 325 may provide
radial support to
motor shaft 210 below thrust bearing assembly 215.
Turning to FIG. 4, split ring 400 may hold thrust bearing assembly 215 in
place axially
on motor shaft 210. Split ring 400 may be "split" and/or formed of two or more
pieces that
connect together around shaft 210 to form a ring shape. Split ring 400 may be
similar to a key
but extending circumferentially around shaft 210, rather than axially along
shaft 210. Split ring
400 may be seated within split ring groove 600 (shown in FIG. 6) around motor
shaft 210, just
below and/or adjacent to splines 610 at the top of motor shaft 210. Thrust
runner 225 may be
positioned such that base 305 extends around motor shaft 210 below split ring
400. Base 305
may be keyed and/or secured to shaft 210 below split ring 400, such that
thrust runner 225
rotates with shaft. Tubular extension 310 may surround and/or be outward of
split ring 400.
Tubular extension 310 may serve as a direct or indirect barrier to radial
expansion of split ring
400. As shown in FIG. 4, lock ring 300 is threaded within thrust runner 225
and surrounds split
ring 400, and tubular extension 310 of thrust runner 225 surrounds lock ring
300. Lock ring
300 may include a lock ring groove or shoulder 405 that extends over and/or
above the top of
split ring 400. Lock ring 300 may be sandwiched above base 305 of thrust
runner 225 and
below shoulder 405 of lock ring 300. In some embodiments, one or more set
screws 410 may
optionally extend axially through apertures 415 (shown in FIG. 6) in lock ring
300 and engage
base 305 of thrust runner 225, which may further secure and/or prevent backing
off of lock ring
300.
FIG. 5 and FIG. 6 illustrate three set screws dispersed circumferentially
around
threaded lock ring 300, engaging with thrust runner 225. As shown in FIG. 5,
when threaded
to thrust runner 225, the top surface of lock ring 300 may be flush or
substantially thrust with
the top surface of thrust runner 225 in embodiments where lock ring 300
threads inside thrust
runner 225. Top surface of lock ring 300 may also include engagements holes
500. Engagement
holes 500 may be holes or recesses to allow a tool and/or operator to grasp
lock ring 300 and
rotate lock ring 300 in order to thread lock ring 300 to thrust runner 225.
FIG. 6 illustrates an exploded view of thrust bearing assembly 215 showing
split ring
groove 600 in which split ring 400 may be seated. Split ring groove 600 may be
positioned
directly below and/or adjacent to splines 610 and/or splined portion of motor
shaft 210. Base
305 of thrust runner 225 may be keyed to shaft 210 by key 605 that extends
longitudinally
along motor shaft 210 below split ring groove 600. Keyway 1405 (shown in FIG.
14) on the
inner diameter of base 305 of thrust runner 225 may mate with key 605 to allow
thrust runner
225 and attached lock ring 300 to rotate with shaft 210. As shown in FIG. 6,
tubular extension
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310 of thrust runner 225 may form a recess and/or receptacle for lock ring 300
that may fit
inside tubular extension 310 secured by threaded connection between lock ring
threads 320 and
thrust runner threads 315.
FIG. 7- FIG. 10 illustrate an embodiment of thrust bearing assembly 215 where
thrust
runner 225 has male threads and lock ring 300 has female threads. As shown in
FIG. 8 and
FIG. 9, outer diameter of tubular extension 310 of thrust runner 225 may
include runner threads
315, and inner diameter of lock ring 300 may include lock ring threads 320.
Lock ring 300 may
include lock ring threads 320 on inner diameter of lock ring 300 and top
surface 505 of lock
ring 300 may extend over the top of lock ring 300. Top surface 505 may be a
cover plate, and/or
may be annular, surrounding shaft 210 and extending outward from shaft 210 to
at least the
inner diameter of lock ring 300, extending from shaft 210 to the outer
diameter of lock ring
300 and/or extending between the inner and outer diameter of lock ring 300.
When lock ring
300 is threaded to thrust runner 225 with internal lock ring threads 320, top
surface 505 may
extend above the threaded connection and/or above tubular extension 310. Drain
plug 705 is
shown in FIG. 7 and may allow motor oil to be drained from motor head 130 when
ESP
motor 105 is not in use.
Turning to FIG. 9, split ring 400 may be positioned inward of thrust runner
225 and/or
inward of tubular extension 310. In FIG. 9, split ring 400 is shown directly
inward, contacting
and/or adjacent to thrust runner 225 and/or tubular extension 310, such that
thrust runner 225
and/or tubular extension prevents radial expansion of split ring 400. Lock
ring 300 extends
outward of tubular extension 310 and above thrust runner 225. Base 305 is
positioned below
split ring 400 and may prevent downward movement of split ring 400. Top
surface 505 may
serve as a barrier to upward movement of split ring 400. A space 900 may
extend axially
between split ring 400 and top surface 505. Split ring 400 may be prevented
from sliding into
space 900 since thrust runner 225 and/or tubular extension 310 may block split
ring 400 from
expanding radially out of split ring groove 600 in shaft 210. However, in the
unlikely instance
split ring 400 were to dislodge, top surface 505 may sufficiently limit axial
movement of split
ring 400 to prevent shaft 210 fall out.
In some embodiments, rather than or in addition to lock ring 300 attached to
thrust
runner 225 by threaded connection, lock ring 300 and/or split ring 400 may be
held in place
and/or secured to thrust runner 225 by a snap ring. FIG. 11-FIG. 14 illustrate
thrust bearing
assembly 215 employing exemplary snap ring 1300. Turning to FIG. 13, lock ring
300 may sit
within and/or inside of tubular extension 310 of thrust runner 225. Split ring
400 may be
captured within lock ring 300 and thrust runner 225. In the embodiment shown
in FIG. 13, lock
Date Recue/Date Received 2021-07-21
ring 300 extends outward of top portion of split ring 400, and thrust runner
base 305 extends
directly outward of bottom portion of split ring 400. Tubular portion 310
extends outward of
lock ring 300 and indirectly outward of split ring 400. Tubular portion 310 of
thrust runner may
include a snap ring groove 1400 proximate and/or near the top of tubular
portion. Snap ring
1300 may be snapped and/or seated into snap ring groove 1400 to fiimly secure,
sandwich,
squeeze and/or hold lock ring 300 in position within recess of thrust runner
225. Snap ring
1300 may extend partially into snap ring groove 1400 on an outward side (outer
diameter) and
partially over the top of lock ring 300 on an inward side (inner diameter),
which may prevent
upward movement of lock ring 300 with respect to thrust runner 225. As shown
in FIG. 14,
snap ring 1300 may be a semi-flexible metal ring with open ends, such as a
circlip, c-clip,
Seeger ring or another similar fastener or retaining ring that permits
rotation of lock ring 300
while preventing axial movement. Snap ring 1300 may be used instead of threads
315, 320 or
in addition to threads 315, 320.
An electric submersible motor thrust bearing system has been described.
Further
modifications and alternative embodiments of various aspects of the invention
may be
apparent to those skilled in the art in view of this description. Accordingly,
this description is
to be construed as illustrative only and is for the purpose of teaching those
skilled in the art
the general manner of carrying out the invention. It is to be understood that
the forms of the
invention shown and described herein are to be taken as the presently
preferred embodiments.
Elements and materials may be substituted for those illustrated and described
herein, parts
and processes may be reversed, and certain features of the invention may be
utilized
independently, all as would be apparent to one skilled in the art after having
the benefit of
this description of the invention. Changes may be made in the elements
described herein
without departing from the scope and range of equivalents as described in the
following
claims. In addition, it is to be understood that features described herein
independently may, in
certain embodiments, be combined.
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