U.S. patent application number 13/800150 was filed with the patent office on 2014-09-18 for electric machine and associated method.
This patent application is currently assigned to REGAL BELOIT AMERICA, INC.. The applicant listed for this patent is REGAL BELOIT AMERICA, INC.. Invention is credited to Lynn Edwin Fisher, Michael Allen Marks.
Application Number | 20140270615 13/800150 |
Document ID | / |
Family ID | 51527391 |
Filed Date | 2014-09-18 |
United States Patent
Application |
20140270615 |
Kind Code |
A1 |
Fisher; Lynn Edwin ; et
al. |
September 18, 2014 |
ELECTRIC MACHINE AND ASSOCIATED METHOD
Abstract
A bearing assembly cooperates with a bearing seat formed in a
bearing housing and includes a bearing having an inner ring, an
outer ring and a rolling element in engagement with the rings and
an anti-rotation device. The anti-rotation device engages the outer
ring to the bearing housing limiting rotation of the outer ring
within the bearing seat. The anti-rotation device includes a first
feature engaging the outer ring and a second feature engaging the
bearing housing. The features limit the rotation of the outer ring
within the bearing seat. The first feature has an internal surface
for engagement the outer ring and the second feature includes an
engagement surface for engaging a protrusion extending from the
bearing housing.
Inventors: |
Fisher; Lynn Edwin; (Fort
Wayne, IN) ; Marks; Michael Allen; (Fort Wayne,
IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
REGAL BELOIT AMERICA, INC. |
Beloit |
WI |
US |
|
|
Assignee: |
REGAL BELOIT AMERICA, INC.
Beloit
WI
|
Family ID: |
51527391 |
Appl. No.: |
13/800150 |
Filed: |
March 13, 2013 |
Current U.S.
Class: |
384/513 |
Current CPC
Class: |
H02K 5/1732 20130101;
F16C 2380/26 20130101; F16C 2226/50 20130101; F16C 35/042 20130101;
F16C 35/067 20130101; F16C 35/077 20130101; F16C 25/083
20130101 |
Class at
Publication: |
384/513 |
International
Class: |
F16C 33/58 20060101
F16C033/58; F16C 35/067 20060101 F16C035/067 |
Claims
1. A bearing assembly for use in an electric machine, said assembly
for cooperation with a bearing seat formed in a bearing housing,
said assembly comprising: a bearing, said bearing including an
inner ring, an outer ring and a rolling element in engagement with
said inner ring and said outer ring; and an anti-rotation device,
said anti-rotation device adapted for engagement with the outer
ring of said bearing and with the bearing housing to limit the
rotation of the outer ring of said bearing within the bearing seat
formed in the bearing housing, said anti-rotation device including
a first feature for engagement with the outer ring of said bearing
and a second feature for engagement with the bearing housing, said
first feature and said second feature adapted to limit the rotation
of the outer ring of said bearing within the bearing seat formed in
the bearing housing, said first feature including an internal
surface for engagement with said outer ring of said bearing and
said second feature including an engagement surface for engagement
with a protrusion extending from the bearing housing.
2. An assembly in accordance with claim 1, where the internal
surface of said anti-rotation device has an interference fit with
said outer ring of said bearing.
3. An assembly in accordance with claim 1: wherein said
anti-rotation device comprises a ring; and wherein said first
feature comprises an interior surface of said ring.
4. An assembly in accordance with claim 3, wherein said
anti-rotation device further comprises an outer flange extending
outwardly from a first end of said ring.
5. An assembly in accordance with claim 3, wherein said
anti-rotation device further comprises an inner flange extending
inwardly from a second end of said ring, opposed to the first end
of said ring.
6. An assembly in accordance with claim 4: Wherein the outer flange
defines a first recess for cooperation with the protrusion.
7. An assembly in accordance with claim 4: wherein the first recess
comprises a first generally rectangular slot extending inwardly
from the outer edge of the outer flange; and further comprising a
second generally rectangular slot, opposed to the first slot and
extending inwardly from the outer edge of the outer flange.
8. An anti-rotation device for use with a bearing in an electric
machine, said anti-rotation device adapted for engagement with the
outer ring of said bearing and with the bearing housing to limit
the rotation of the outer ring of said bearing within the bearing
seat formed in the bearing housing, said anti-rotation device
including a first feature for engagement with the outer ring of
said bearing and a second feature for engagement with the bearing
housing, said first feature and said second feature adapted to
limit the rotation of the outer ring of said bearing within the
bearing seat formed in the bearing housing, said first feature
including an internal surface for engagement with said outer ring
of said bearing and said second feature including an engagement
surface for engagement with a protrusion extending from the bearing
housing, said anti-rotation device comprises a ring and said first
feature comprises an interior surface of said ring.
9. An anti-rotation device in accordance with claim 8, wherein the
internal surface of said anti-rotation device has an interference
fit with said outer ring of said bearing.
10. An anti-rotation device in accordance with claim 8, wherein
said anti-rotation device further comprises an outer flange
extending outwardly from a first end of said ring.
11. An anti-rotation device in accordance with claim 8, wherein
said anti-rotation device further comprises an inner flange
extending inwardly from a second end of said ring, opposed to the
first end of said ring.
12. An anti-rotation device in accordance with claim 10, wherein
the outer flange defines a first recess for cooperation with the
protrusion.
13. An anti-rotation device in accordance with claim 12: wherein
the first recess comprises a first generally rectangular slot
extending inwardly from the outer edge of the outer flange; and
further comprising a second generally rectangular slot, opposed to
the first slot and extending inwardly from the outer edge of the
outer flange.
14. An electric machine comprising: a housing; a stator secured to
said housing a rotor rotatable associated with said housing, said
rotor supported by a shaft; a bearing having an inner ring and an
outer ring, said bearing rotatably securing said rotor to said
housing; and an anti-rotation device for use with said bearing,
said bearing mounting in housing of an electric machine, said
anti-rotation device adapted for engagement with the outer ring of
said bearing and with the bearing housing to limit the rotation of
the outer ring of said bearing within the bearing seat formed in
the bearing housing, wherein said anti-rotation device includes a
first feature for engagement with the outer ring of the bearing and
a second feature for engagement with the bearing housing, said
first feature and said second feature adapted to limit the rotation
of the outer ring of the bearing within the bearing housing, said
first feature including an internal surface for engagement with
said outer ring of said bearing and said second feature including
an engagement surface for engagement with a protrusion extending
from the bearing housing, said anti-rotation device comprises a
ring and said first feature comprises an interior surface of said
ring.
15. An electric machine in accordance with claim 14, where the
internal surface of said anti-rotation device has an interference
fit with said outer ring of said bearing.
16. An electric machine in accordance with claim 14, wherein said
anti-rotation device further comprises an outer flange extending
outwardly from a first end of said ring.
17. An electric machine in accordance with claim 14, wherein said
anti-rotation device further comprises an inner flange extending
inwardly from a second end of said ring, opposed to the first end
of said ring.
18. An electric machine in accordance with claim 16, wherein the
first recess comprises a first generally rectangular slot extending
inwardly from the outer edge of the outer flange.
19. An electric machine in accordance with claim 18, further
comprising a second generally rectangular slot, opposed to the
first slot and extending inwardly from the outer edge of the outer
flange.
20. A method for containing a bearing in an electric machine,
comprising: providing an anti-rotation device for use with a
bearing having an inner ring and an outer ring, engaging the
anti-rotation device with the outer ring of said bearing; and
engaging the anti-rotation device with the bearing housing to limit
the rotation of the outer ring of said bearing within the bearing
seat formed in the bearing housing, said anti-rotation device
including a first feature for engagement with the outer ring of the
bearing, said first feature comprises an internal surface for
engagement with said outer ring of said bearing; and a second
feature for engagement with the bearing housing, said first feature
and said second feature adapted to limit the rotation of the outer
ring of the bearing within the bearing housing, said second feature
comprising an engagement surface for engagement with a protrusion
extending from the bearing housing, wherein said anti-rotation
device comprises a ring and wherein said first feature comprises an
interior surface of said ring, wherein said anti-rotation device
further comprises an outer flange extending outwardly from a first
end of said ring, wherein the recess comprises a first generally
rectangular slot extending inwardly from the outer edge of the
outer flange and further comprising a second generally rectangular
slot, opposed to the first slot and extending inwardly from the
outer edge of the outer flange.
Description
BACKGROUND OF THE INVENTION
[0001] The embodiments described herein relate generally to an
electric machine, and more specifically, to a bearing assembly with
a relative motion [bearing creep] impeding device associated with
the electric machine.
[0002] An electric machine is typically in the form of an electric
generator or an electric motor. The machine typically has a
centrally located shaft that rotates relative to the machine.
Electrical energy applied to coils within the motor initiates this
relative motion which transfers the power to the shaft and,
alternatively, mechanical energy from the relative motion of the
generator excites electrical energy into the coils. For expediency
the machine will be described hereinafter as a motor. It should be
appreciated that a motor may operate as a generator and vice
versa.
[0003] A stationary assembly, also referred to as a stator,
includes a stator core and coils or windings positioned around
portions of the stator core. It is these coils to which energy is
applied to initiate this relative motion which transfers the power
to the shaft. These coils are formed by winding wire, typically
copper, aluminum or a combination thereof, about a central core to
form the winding or coil.
[0004] The centrally located shaft supports a rotor. The rotor is
the non-stationary part of a rotary electric motor, electric
generator or alternator. Motor efficiency is improved by decreasing
the degree of slip between the rotor and the stator for a given
load. One way to decrease the slip is by increasing the mass of the
rotor. The rotor includes conductors, conductor bars and end-plates
which transfer current, magnetic field and torque to the rotor and
consequently torque to the shaft.
[0005] The shaft rotatably supports the substantial weight of the
rotor within the electric machine. At least one bearing and
typically a pair of spaced apart bearings support the shaft within
a housing of the electric machine. The bearings may be any bearing
capable of supporting the loads involved and of enduring the
rotational speeds of the motor. Typically modern electric machines
utilize rolling element bearings, typically ball bearings to
support the shaft and rotor. The ball bearings include an inner
ring and an outer ring separated by a series of spherical elements
or balls. While the shaft is typically rigidly secured to the inner
ring, the outer ring is permitted to move axial in the housing, to
accommodate various phenomenon including temperature changes,
dissimilar materials, and tolerance stacks.
[0006] When the bearing is positioned with the shaft horizontal to
the horizon or ground, a substantial radial load from the rotor is
applied to the bearing. This radial load serves to inhibit relative
motion or rotation of the bearing outer ring in the housing.
However when the bearing is positioned with the shaft vertical with
respect to the horizon or ground, radial loads can be zero or
minimal, permitting relative slippage to occur between the bearing
outer ring and the housing.
[0007] The initial relative slippage is exasperated by the
formation of metal debris that forms a lapping compound between the
bearing outer ring and the housing bore. This lapping may quickly
greatly enlarge the housing bore, causing excessive noise and
excessive movement between the motor stator and the motor rotor,
resulting in rotor/stator strike. The noise and strike may lead to
early bearing and resultant motor failure.
[0008] Many practical applications utilize motors with vertical
shafts. For example, pumps for pools and spas and cooling fans,
particularly those to cool air conditioning compressors. These
applications are plagued with bearing failures caused by the
relative motion of the motor bearing outer ring in the motor
housing, also known as bearing creep. Typically, vertical cooling
fan motors have a vertical shaft extending upwardly from the motor
and from which a fan is attached. The motor typically has an upper
unconstrained bearing and a lower constrained bearing. The upper
unconstrained bearing, being closer to the fan, has a greater
tendency for creep, but creep can occur in any bearing application,
particularly those where accommodation is made for the bearing to
move axially with respect to its housing.
[0009] Various methods are used to limit the bearing creep. One
method is to eliminate any relative motion, including axial motion,
by providing an interference fit between the bearing outer ring and
the housing or by using an adhesive between the outer ring and
housing. However any solution that eliminates all relative motion
has the disadvantage of not accommodating various phenomenon
including temperature changes, dissimilar materials, and tolerance
stacks that affect the relative axial position of the inner ring
with respect to the outer ring. Such a solution may result in
excessive bearing preloads and reduced bearing life. Further,
interference fit between both bearing races is not recommended by
bearing manufacturers. Other methods, such as placing an o-ring, a
polymer ring, an EC (expansion compensating bearing), between the
bearing and the housing are either ineffective or not sufficiently
durable. The present invention is directed to alleviate at least
some of these problems with the prior art.
BRIEF DESCRIPTION OF THE INVENTION
[0010] In one aspect, a bearing assembly cooperates with a bearing
seat formed in a bearing housing and includes a bearing having an
inner ring, an outer ring and a rolling element in engagement with
the rings and an anti-rotation device. The anti-rotation device
engages the outer ring to the bearing housing limiting rotation of
the outer ring within the bearing seat. The anti-rotation device
includes a first feature engaging the outer ring and a second
feature engaging the bearing housing. The features limit the
rotation of the outer ring within the bearing seat. The first
feature has an internal surface for engagement the outer ring and
the second feature includes an engagement surface for engaging a
protrusion extending from the bearing housing.
[0011] In another aspect, an anti-rotation device for use with a
bearing in an electric machine is provided. The anti-rotation
device is adapted for engagement with the outer ring of the bearing
and with the bearing housing to limit the rotation of the outer
ring of the bearing within the bearing seat formed in the bearing
housing. The anti-rotation device includes a first feature for
engagement with the outer ring of the bearing and a second feature
for engagement with the bearing housing. The first feature and the
second feature are adapted to limit the rotation of the outer ring
of the bearing within the bearing seat formed in the bearing
housing. The first feature includes an internal surface for
engagement with the outer ring of the bearing and the second
feature includes an engagement surface for engagement with a
protrusion extending from the bearing housing. The anti-rotation
device includes a ring and the first feature includes an interior
surface of the ring.
[0012] In yet another aspect, an electric machine includes a
housing, a stator secured to the housing, a rotor, a bearing and an
anti-rotation device. The rotor is rotatably associated with the
housing. The rotor is supported by a shaft. The bearing has an
inner ring and an outer ring. The bearing rotatably secures the
rotor to the housing. The anti-rotation device cooperates with the
bearing which is mounted in the housing of an electric machine. The
anti-rotation device engages with the outer ring of the bearing and
with the bearing housing to limit the rotation of the outer ring of
the bearing within the bearing seat which is formed in the bearing
housing. The anti-rotation device includes a first feature for
engagement with the outer ring of the bearing and a second feature
for engagement with the bearing housing. The first feature and the
second feature limit the rotation of the outer ring of the bearing
within the bearing housing. The first feature includes an internal
surface for engagement with the outer ring of the bearing and the
second feature includes an engagement surface for engagement with a
protrusion extending from the bearing housing. The anti-rotation
device includes a ring and the first feature includes an interior
surface of the ring.
[0013] In yet another aspect, a method for containing a bearing in
an electric machine is provided. The method includes the steps of
providing an anti-rotation device for use with a bearing having an
inner ring and an outer ring, of engaging the anti-rotation device
with the outer ring of the bearing and of engaging the
anti-rotation device with the bearing housing to limit the rotation
of the outer ring of the bearing within the bearing seat formed in
the bearing housing. The anti-rotation device includes a first
feature for engagement with the outer ring of the bearing. The
first feature includes an internal surface for engagement with the
outer ring of the bearing and a second feature for engagement with
the bearing housing. The first feature and the second feature limit
the rotation of the outer ring of the bearing within the bearing
housing. The second feature has an engagement surface for
engagement with a protrusion extending from the bearing
housing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a perspective view of a motor including a bearing
assembly having an anti-rotation device embodying the present
invention;
[0015] FIG. 2 is a cross sectional view of the end cap assembly of
the motor of FIG. 1 along the line 2-2 in the direction of the
arrows;
[0016] FIG. 3 is an exploded view, partly in cross section, of the
end cap assembly of FIG. 2;
[0017] FIG. 4 is a plan view an anti-rotation device for use in the
end cap assembly of FIG. 2;
[0018] FIG. 5 is a partial enlarged cross sectional view of the end
cap assembly of FIG. 2;
[0019] FIG. 6 is a partial further enlarged cross sectional view of
the end cap assembly of FIG. 2.
[0020] FIG. 7 is a cross sectional view of the anti-rotation device
of FIG. 4 along the line 7-7 in the direction of the arrows;
[0021] FIG. 8 is a cross sectional view of the anti-rotation device
of FIG. 4 along the line 8-8 in the direction of the arrows;
[0022] FIG. 9 is an enlarged partial cross sectional view of FIG.
7; and
[0023] FIG. 10 is a flow chart of an exemplary method for utilizing
the bearing assembly as shown in FIG. 3.
DETAILED DESCRIPTION OF THE INVENTION
[0024] The methods, systems, and apparatus described herein provide
improved support for a rotor within a stator of an electric
machine. Bearings that support the rotor in the stator need to
provide for axial movement of the bearing relative to the machine
housing, while inhibiting rotation of the bearing outer ring in the
bearing housing. Difficulties may occur providing for the axial
movement, while inhibiting rotation. Bearing creep may occur
resulting in noise and reduced life for the electric machine.
[0025] The methods, systems, and apparatus described herein assist
in the proper support for a rotor within a stator of an electric
machine. The methods, systems, and apparatus described herein may
also facilitate quieter operation and increased speed. Furthermore,
the methods, systems, and apparatus described herein provide for an
improved life and durability of the motor and its appeal to the
customer.
[0026] Technical effects of the methods, systems, and apparatus
described herein include at least one of improved performance and
quality and reduced labor costs.
[0027] FIG. 1 is a perspective view of an exemplary electric
machine 10. While the machine 10 may be any electric machine
including generators and motors, typically the machine is an
electric motor. The motor 10 may have any orientation, horizontal,
vertical or otherwise. As shown the motor has a vertical
orientation with the shaft extending upwardly out of the motor
housing.
[0028] The electric machine 10 includes a stationary assembly 12.
Electric machine 10 also includes a machine assembly housing 18 and
a rotatable assembly 22. Machine assembly housing 18 defines an
interior 24 and an exterior 26 of machine 10 and is configured to
at least partially enclose and protect stationary assembly 12 and
rotatable assembly 22. Stationary assembly 12 includes a stator
core 28, which includes a plurality of stator teeth or projections
30. Stator end caps are positioned over opposed end teeth of the
plurality of stator teeth 30. Wire is wound around stator teeth 30
and the stator end caps to form each of a plurality of windings
32.
[0029] In an exemplary embodiment, stationary assembly 12 is a
three phase salient pole stator assembly. Stator core 28 is formed
from a stack of laminations made of a highly magnetically permeable
material, and windings 32 are wound on stator core 28 in a manner
known to those of ordinary skill in the art. Laminations are
stacked such that stator core 28 reaches a predefined length 34. In
the exemplary embodiment, the plurality of laminations that form
the stator core 28 may be either interlocked or loose laminations.
In an alternative embodiment, stator core 28 is a solid core. For
example, stator core 28 may be formed from a soft magnetic
composite (SMC) material, a soft magnetic alloy (SMA) material,
and/or a powdered ferrite material using a sintering process. In
another alternate embodiment, the windings 32 are wound around a
plurality of spools (not shown), each of which is removably fitted
to one of the stator teeth 30.
[0030] In one embodiment, rotatable assembly 22 includes a
permanent magnet rotor core 36 and a shaft 38 and is configured to
rotate around an axis of rotation 40. In the exemplary embodiment,
rotor core 36 is formed from a stack of laminations made of a
magnetically permeable material and is substantially received in a
central bore of stator core 28. While FIG. 1 is an illustration of
a three phase electric motor, the methods and apparatus described
herein may be included within machines having any number of phases,
including single phase and multiple phase electric machines.
[0031] In the exemplary embodiment, electric machine 10 is coupled
to a fan (not shown) for moving air through an air handling system,
for blowing air over cooling coils, and/or for driving a compressor
within an air conditioning/refrigeration system. The shaft 38 of
the machine 10 extends as shown vertically upward from the machine
and is used to secure the fan to the shaft.
[0032] Alternatively, the electric machine may be coupled to a pump
for use in pools, spas, and the like. More specifically, machine 10
may be used in air moving applications used in the heating,
ventilation, and air conditioning (HVAC) industry, for example, in
residential applications using 1/3 horsepower (hp) to 1 hp motors
or greater and/or in commercial and industrial applications and
hermetic compressor motors used in air conditioning applications
using higher horsepower motors, for example, but not limited to
using 1/3 hp to 7.5 hp motor or greater. Although described herein
in the context of an air handling system, electric machine 10 may
engage any suitable work component and be configured to drive such
a work component. Alternatively, electric machine 10 may be coupled
to a power conversion component, for example, an engine, a wind
turbine rotor, and/or any other component configured to rotate
rotatable assembly 22 to generate electricity using electric
machine 10.
[0033] Continuing to refer to FIG. 1, the housing 18 of motor 10
includes a central portion 42 and opposed motor end caps 44 and 46,
secured to central portion 42 of housing 18. Bearing assemblies 48
and 50 are mounted in end caps 44 and 46, respectively, and support
the shaft 38 of rotor 22 for rotation within housing 18 of motor
10. It should be appreciated that only one end cap may be used with
the other end cap being integral with the central portion of the
housing.
[0034] According to the present invention, one or both of the
bearing assemblies 48 and 50 include an anti-rotation device 52
according to the present invention. The bearing assemblies 48 and
50 support opposed ends of shaft 38. As shown bearing assembly 52
in the upper end cap 44 is typically is not captive to the cap 44
(the bearing assembly 52 is unconstrained (not contained on its
lower side and can move to the down relative to end cap 44).
Conversely, the bearing assembly 50 in the lower end cap 46 is
typically constrained. The shaft 38 in turn supports a rotor, for
example and as shown, permanent magnet rotor core 36.
[0035] Continuing to refer to FIG. 1, the bearing assembly 48 and
the bearing assembly 50 may be similar, and for simplification
identical to each other. Therefore the description of bearing
assembly 48 may equally apply to bearing assembly 50.
[0036] Referring now to FIGS. 2 and 3, the bearing assembly 48
includes the anti-rotation device 52 as well as bearing 54. The
bearing 54 may be any bearing capable of supporting the rotor core
36. For example the bearing may be any type of rolling element
bearing. To permit operation speeds for modern electrical machine
and to provide sufficient bearing life and as shown in FIG. 3, the
bearing may be a ball bearing 54. The bearing 54 includes an inner
ring 56 surrounded on its outer periphery or inner race 58 by
rolling elements or balls 60. A bearing ball retainer, not shown,
may be used to space the balls 60 about the bearing. An outer ring
62 surrounds balls 60 on its inner periphery or outer race 64 of
outer ring 62.
[0037] The inner ring 56 includes an inner surface or bore 66 to
which the shaft 38 (see FIG. 1) is fitted. The shaft 38 may have
any suitable fit with the bore 66 and may be in clearance, slip fit
or interference fit with the bore 66. The shaft may be fixed to the
bore of bearing by a press or interference fit or may be locked to
it by adhesives or a device, such as a bearing collar, not
shown.
[0038] According to the present invention and as shown in FIGS. 2
and 3, the bearing assembly includes the anti-rotation device 52.
The anti-rotation device 52, as shown, engages the outer ring 62 of
bearing 54. The device 52 may engage the outer ring 62 at any
position of the device and at any position of the ring. As shown
the device has a device bore 68 which engages outer periphery or
outside diameter 70 of outer ring 62 of bearing 54.
[0039] Referring now to FIG. 3, the device 52 may engage the outer
ring 62 in any effective way, by a first feature or device bearing
engagement feature 72 of device 52, for example, feature 72 may be
in the form of providing a device (not shown) or the feature 72 may
be an adhesive, or the device and the ring may have mating features
(not shown) to engage each others. As shown in FIG. 3, the feature
72 is in the form of an interference fit between device bore 68 of
device 52 and the outer periphery or outside diameter 70 of outer
ring 62 of bearing 54.
[0040] The device 52 may further engage the outer ring 62 at outer
ring end face 63 of outer ring 62. The engagement of device 52 to
end face 63 may, as shown, be made by inner face 65 of an inner
flange 67 of device 52 extending inwardly from a first end 59 of
ring portion or central portion 61 of device 52. The device 52 may
function properly without the engagement of device 52 to end face
63, but the engagement of device 52 to end face 63 provides for
axial positioning of the device 52 with respect to bearing 54 and
with respect to the end cap 44.
[0041] As shown in FIG. 1, the upper end cap 44 is on the loaded
end of the motor 10, where the outer ring 62 is not captive to the
cap 44 (the outer ring 62 is not contained below or on the right of
the ring 62 and can move to the right or downwardly relative to end
cap 44 as shown). It should be appreciated that the anti-rotation
device 52 may also be used on lower end cap 46 (see FIG. 1) which
may be the non-loaded end of the motor 10. In such an application,
the anti-rotation device 52 could be used as a method of capturing
the outer ring of the bearing of bearing assembly 50 (see FIG. 1)
from rotation within end cap and may replace or supplement normal
locking mechanisms such as clamps.
[0042] Referring again to FIG. 3, the anti-rotation device 52, as
shown, also engages the motor assembly housing 18 (see FIG. 1) in
any effective way, by a second feature or device housing engagement
feature 74 of device 52, for example, the second feature may be in
the form of an additional engaging device (not shown) or, as shown,
the second feature 74 may cooperate with a mating feature on the
housing 18 to engage each other.
[0043] As shown in greater detail in FIG. 4, the second feature or
device housing engagement feature 74 is in the form of a void 74.
The void 74 of the anti-rotation device 52 is defined by an
engagement feature that cooperates with a housing device engagement
feature 76 of housing 18 located on the assembly housing 18. The
housing device engagement feature 76 may be any feature that
cooperates with the device housing engagement feature 74 of device
52 to inhibit rotation of the device 52 with respect to the bearing
outer ring 62 of bearing 54. The housing device engagement feature
76 may be a separate component or, as shown, be integral with
housing 18 (or end cap 44 of housing 18). The housing device
engagement feature 76 as shown is a protrusion 76 that extends into
void 74 of the anti-rotation device 52 engaging the engaging
feature which defines the void 74.
[0044] While the void 74 and the protrusion 76 may have any shape,
for simplicity and as shown in phantom in FIG. 4, the protrusion 76
is defined by a housing lug 78 formed in housing bore 80 of end cap
44 of housing 18. For simplicity and to provide an effective mating
feature, the void 74 is defined by a notch 75 formed by 2 spaced
apart parallel radial walls 79 positioned on opposed ends of a
tangential wall 81 on the anti-rotation device 52. The notch 75 has
a notch width NW and a notch depth ND. It should be appreciate that
the notch 75 may have alternate shapes including but not limited to
a hemispherical shape, an arcuate shape, an portion of a polygon
shape (other than portion of a square shape as shown) or any
irregular shape that forms a void. The portion of a square shape
shown is simple, easy to manufacture and provides ample contact and
rigidity with a mating protrusion 76 in the end cap 44.
[0045] Referring now to FIGS. 5 and 6, to permit axial movement of
the bearing 54 in the end cap 44 of housing 18, outer surface 83 of
anti-rotation device 52 is preferably in a mating fit/clearance
with housing bore 80 and the anti-rotation device notch 75 is
preferably in a mating fit/clearance with housing protrusion or lug
76. The clearance of the anti-rotation device 52 with the housing
bore 80 may permit a slight relative angular movement between each
other which may be less than 30 degrees or from 0 to 15
degrees.
[0046] The anti-rotation device 54 may seat against the face of the
housing bore 80, or preferably and as shown in FIGS. 2, 3, 5 and 6,
a load washer in the form of, for example, a wavy washer 84 may be
positioned between the anti-rotation device 54 and the face of the
housing bore 80. The wavy washer 84 serves to place a preload on
the bearing 54.
[0047] Referring now to FIGS. 7 and 8, the anti-rotation device 52
is shown in greater detail. The anti-rotation device 52, as shown,
is generally in the shape of a ring or hoop defined by outer
surface 83, bore 68 and opposed first and second faces 87 and 86,
respectively, and defining central portion 61 of device 52. Outer
edges 88 formed between the first face 87 and outer surface 83 may
be rounded, as shown, or chamfered. Likewise inner edge 90 between
the second face 86 and bore 68 may be rounded or chamfered, as
shown.
[0048] The anti-rotation device 52 may include an outer flange 85
extending outwardly from the second face 86 of the central portion
61 of device 52. The outer flange 85 serves to add rigidity and
strength to the device 52 and provides a location for the
engagement feature 74. Further the anti-rotation device 52 may
include the inner flange 67 extending inwardly from the first end
59 of the central portion 61 of device 52. The inner flange 67
serves to add rigidity and strength to the device 52.
[0049] Referring again to FIG. 4, in addition to the void or device
housing engagement feature 74 in the form of notch 75, additional
engagement features may be provided with the anti-rotation device
52. For example, and as shown in FIG. 5, the anti-rotation device
52 may include an additional or second device housing engagement
feature 92.
[0050] Continuing to refer to FIG. 4, the second device housing
engagement feature 92 may be defined by second notch 92 having
radial walls 79 and a tangential wall 81 which engages a second
housing device engagement feature in the form of second housing
protrusion or lug 94 (see FIG. 4). The second notch 92 may be
similar or identical to first notch 75 and may be positioned
anywhere else on the outer flange 85 of device 52. As shown and for
simplicity, the second notch 92 is positioned opposed to first
notch 75.
[0051] The anti-rotation device 52 may have any desired size and
shape and as shown in FIG. 5, is sized to slidably fit with bore 80
of end cap 44 and to be fixedly secured to bearing outer ring
62.
[0052] Referring again to FIG. 7, the anti-rotation device 52 has a
width W between the first face 87 and the second face 86. Width W
may be the same as the width of bearing 54, as shown, or smaller or
larger.
[0053] Referring again to FIG. 5, the bore 68 of device 52 has a
diameter of BD and the outer surface 83 of the device 52 has an
outside diameter of DD.
[0054] The anti-rotation device 52 may be made of any suitable
durable material or materials and may, for example be made of a
metal, a polymer or a composite material. The device may be made by
and suitable process, such as molding, casting, forming or
machining, etc.
[0055] Referring now to FIG. 6, anti-rotation device 52 is shown
assembled over the bearing 54 to form bearing assembly 50.
[0056] Referring again to FIG. 3, the anti-rotation device 52, the
bearing 54, are shown in an exploded position for assembly into
bore 80 of end cap 44 of housing 18 of motor 10. It should be
appreciated that additional components may be used to complete the
motor 10 of present invention. For example, as shown, a wavy washer
84 may be positioned in the bore 80 of end cap 44. Also, a snap
ring (not shown) may be positioned in groove (not shown) of shaft
38 of motor 10.
[0057] Referring now to FIG. 10, a flow chart of an exemplary
method 200 for containing a bearing in an electric machine (see
FIG. 1) is shown. The method 200 includes the step 202 of providing
anti-rotation device 52 (see FIG. 4) for use with bearing. 54
having an inner ring and an outer ring, the step 204 of engaging
the anti-rotation device with the outer ring of said bearing and
the step 206 of engaging the anti-rotation device with the bearing
housing to limit the rotation of the outer ring of said bearing
within the bearing seat formed in the bearing housing.
[0058] Referring again to FIGS. 3 and 4, the anti-rotation device
52 includes the first feature or device bearing engagement feature
72 for engagement with the outer ring 62 of the bearing 54. The
anti-rotation device 52 also includes a second feature or device
housing engagement feature 74 for engagement with the bearing
housing 18. The first feature 72 and said second feature 74 are
adapted to limit the rotation of the outer ring 62 of the bearing
54 within the bearing housing 18. The device bearing engagement
feature 72 includes an internal surface 68 for engagement with the
outer ring 62 of the bearing 54. The device housing engagement
feature 74 includes a void or recess 74 for engagement with a
protrusion or lug 76 extending from the bearing housing 18. The
anti-rotation device 52 is in the form of a ring. The device
bearing engagement feature 72 includes an interior surface 68 of
said ring. The recess or void 74 is defined by a notch 75 on the
outer surface 83 of the device 52.
[0059] The methods, systems, and apparatus described herein
facilitate efficient and economical assembly of an electric motor.
Exemplary embodiments of methods, systems, and apparatus are
described and/or illustrated herein in detail. The methods,
systems, and apparatus are not limited to the specific embodiments
described herein, but rather, components of each apparatus and
system, as well as steps of each method, may be utilized
independently and separately from other components and steps
described herein. Each component, and each method step, can also be
used in combination with other components and/or method steps.
[0060] When introducing elements/components/etc. of the methods and
apparatus described and/or illustrated herein, the articles "a",
"an", "the", and "said" are intended to mean that there are one or
more of the element(s)/component(s)/etc. The terms "comprising",
"including", and "having" are intended to be inclusive and mean
that there may be additional element(s)/component(s)/etc. other
than the listed element(s)/component(s)/etc.
[0061] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal language of the claims.
* * * * *