U.S. patent application number 13/778574 was filed with the patent office on 2014-08-28 for laminated rotor with improved magnet adhesion and method of fabricating.
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 Daniel S. Figgins, Jeffrey A. Hall.
Application Number | 20140239764 13/778574 |
Document ID | / |
Family ID | 51387422 |
Filed Date | 2014-08-28 |
United States Patent
Application |
20140239764 |
Kind Code |
A1 |
Figgins; Daniel S. ; et
al. |
August 28, 2014 |
LAMINATED ROTOR WITH IMPROVED MAGNET ADHESION AND METHOD OF
FABRICATING
Abstract
In one aspect, a moisture resistant rotor sleeve is provided.
The rotor sleeve includes a plurality of stacked laminations
forming a sleeve having an outer periphery, an inner periphery, and
spaces between adjacent laminations. The rotor sleeve also includes
a sealant applied into the spaces between the adjacent laminations,
wherein the sealant seals the spaces to prevent air from traveling
through the spaces of the sleeve between the inner periphery and
the outer periphery.
Inventors: |
Figgins; Daniel S.; (Fort
Wayne, IN) ; Hall; Jeffrey A.; (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: |
51387422 |
Appl. No.: |
13/778574 |
Filed: |
February 27, 2013 |
Current U.S.
Class: |
310/156.12 ;
29/598; 310/216.065 |
Current CPC
Class: |
H02K 1/2753 20130101;
H02K 1/2706 20130101; H02K 15/03 20130101; Y10T 29/49012 20150115;
H02K 1/30 20130101 |
Class at
Publication: |
310/156.12 ;
310/216.065; 29/598 |
International
Class: |
H02K 1/28 20060101
H02K001/28; H02K 15/10 20060101 H02K015/10; H02K 1/27 20060101
H02K001/27 |
Claims
1. A moisture resistant rotor sleeve comprising: a plurality of
stacked laminations forming a sleeve having an outer periphery, an
inner periphery, and spaces between adjacent laminations; and a
sealant applied into said spaces between said adjacent laminations,
wherein said sealant seals said spaces to prevent air from
traveling through said spaces of said sleeve between said inner
periphery and said outer periphery.
2. The rotor sleeve of claim 1, wherein said sleeve does not have
sealant on at least one of a sleeve inner periphery surface and a
sleeve outer periphery surface.
3. The rotor sleeve of claim 1, wherein said sleeve further
comprises said sealant on at least one of a sleeve inner periphery
surface and a sleeve outer periphery surface.
4. The rotor sleeve of claim 1, wherein said sealant is applied in
substantially the entire space between said adjacent laminations
from said inner periphery to said outer periphery.
5. The rotor sleeve of claim 1, wherein said sealant is one of a
varnish, an anaerobic wicking grade thread locker, a casting
porosity sealant, a polyurethane, and an enamel paint.
6. The rotor sleeve of claim 1, further comprising at least one
permanent magnet coupled to said sleeve outer periphery, wherein
said sealant facilitates preventing moisture from reaching the
interface between said outer periphery and said permanent magnet to
increase the integrity of the coupling therebetween.
7. The rotor sleeve of claim 1, wherein substantially the entire
surface area of said sleeve is coated with said sealant.
8. A rotor comprising: a shaft; a hub coupled to said shaft; a
plurality of stacked laminations forming a sleeve having an outer
periphery, an inner periphery, and spaces between adjacent
laminations, said sleeve coupled to said hub; a sealant applied
into said spaces between said adjacent laminations, wherein said
sealant seals said spaces to prevent air from traveling through
said spaces of said sleeve between said inner periphery and said
outer periphery; and at least one permanent magnet coupled to said
sleeve outer periphery, wherein said sealant facilitates preventing
moisture from reaching the interface between said outer periphery
and said permanent magnet to increase the integrity of the coupling
therebetween.
9. The rotor of claim 8, wherein said sleeve does not have sealant
on at least one of a sleeve inner periphery surface and a sleeve
outer periphery surface.
10. The rotor of claim 8, wherein said sleeve further comprises
said sealant on at least one of a sleeve inner periphery surface
and a sleeve outer periphery surface.
11. The rotor of claim 8, wherein said sealant is applied in
substantially the entire space between said adjacent laminations
from said inner periphery to said outer periphery.
12. The rotor of claim 8, wherein said sealant is one of a varnish,
an anaerobic wicking grade thread locker, a casting porosity
sealant, a polyurethane, and an enamel paint.
13. The rotor of claim 8, wherein substantially the entire surface
area of said sleeve is coated with said sealant.
14. The rotor of claim 13, wherein substantially the entire surface
area of said at least one permanent magnet is coated with said
sealant.
15. The rotor of claim 8, wherein substantially the entire surface
area of said rotor is coated with said sealant.
16. A method of fabricating a moisture resistant rotor sleeve, said
method comprising: providing a sleeve formed from a plurality of
stacked laminations, the sleeve having an outer periphery, an inner
periphery, and spaces between adjacent laminations; and applying a
sealant in the spaces between adjacent laminations such that the
sealant facilitates sealing the spaces to prevent air from
traveling through the spaces of the sleeve between the inner
periphery and the outer periphery.
17. The method of claim 16, wherein applying the sealant comprises
at least one of spraying the sealant into the spaces, dipping the
sleeve in the sealant, brushing the sealant into the spaces, and
rolling the sleeve in a shallow bath of the sealant.
18. The method of claim 16, wherein applying the sealant comprises
applying a sealant in the spaces between adjacent laminations such
that the sealant substantially fills the entire space from the
inner periphery to the outer periphery.
19. The method of claim 16, further comprising coupling at least
one permanent magnet to the sleeve outer periphery, wherein the
sealant facilitates preventing moisture from reaching the interface
between the outer periphery and the permanent magnet to increase
the integrity of the coupling therebetween.
20. The method of claim 19, wherein at least one of a sleeve outer
periphery surface and a sleeve inner periphery surface do not
include the sealant.
Description
BACKGROUND OF THE INVENTION
[0001] The field of the invention relates generally to electric
motors and, more particularly, to sealed laminated rotor
sleeves.
[0002] Various types of electric machines include permanent
magnets. For example, a brushless direct current (BLDC) motor may
include a plurality of permanent magnets coupled to an exterior
surface of a rotor core. Typically, the permanent magnets are
coupled to the exterior surface of the rotor core using an
adhesive. This coupling between the permanent magnets and the rotor
core must resist forces exerted on the permanent magnets during
high speed rotation tending to separate the permanent magnets from
the rotor.
[0003] Some known rotor cores include laminated rotor sleeves.
Under certain environmental conditions, permanent magnets may not
remain adhered to the rotor sleeve with the desired level of
reliability due to gaps in the laminations exposing the adhesive
bond to the environment. Other known rotor cores utilize a solid
sleeve instead of a laminated sleeve and exhibit improved bond
performance. However, such solid sleeve rotor cores are typically
more expensive than laminated sleeve rotor cores. Accordingly,
there is a need for a laminated sleeve rotor core with improved
resistance to the environment and improved magnet adhesion.
BRIEF DESCRIPTION OF THE INVENTION
[0004] In one aspect, a moisture resistant rotor sleeve is
provided. The rotor sleeve includes a plurality of stacked
laminations forming a sleeve having an outer periphery, an inner
periphery, and spaces between adjacent laminations. The rotor
sleeve also includes a sealant applied into the spaces between the
adjacent laminations, wherein the sealant seals the spaces to
prevent air from traveling through the spaces of the sleeve between
the inner periphery and the outer periphery.
[0005] In another aspect, a rotor is provided. The rotor includes a
shaft, a hub coupled to the shaft, and a plurality of stacked
laminations forming a sleeve having an outer periphery, an inner
periphery, and spaces between adjacent laminations. The sleeve is
coupled to the hub and a sealant is applied into the spaces between
the adjacent laminations. The sealant seals the spaces to prevent
air from traveling through the spaces of the sleeve between the
inner periphery and the outer periphery. At least one permanent
magnet is coupled to the sleeve outer periphery. The sealant
facilitates preventing moisture from reaching the interface between
the outer periphery and the permanent magnet to increase the
integrity of the coupling therebetween.
[0006] In yet another aspect, a method of fabricating a moisture
resistant rotor sleeve is provided. The method includes providing a
sleeve formed from a plurality of stacked laminations, the sleeve
having an outer periphery, an inner periphery, and spaces between
adjacent laminations. The method further includes applying a
sealant in the spaces between adjacent laminations such that the
sealant facilitates sealing the spaces to prevent air from
traveling through the spaces of the sleeve between the inner
periphery and the outer periphery.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a perspective cut-away view of an exemplary
electric machine;
[0008] FIG. 2 is a perspective view of an exemplary rotor core that
may be used with the machine shown in FIG. 1;
[0009] FIG. 3 is a perspective view of a portion of the rotor core
shown in FIG. 2;
[0010] FIG. 4 is a detailed view of section 4 shown in FIG. 3;
[0011] FIG. 5 is a cross-sectional view of the rotor shown in FIG.
3 and taken along line 5-5; and
[0012] FIG. 6 is a cross-sectional view of another exemplary rotor
core that may be used with the machine shown in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0013] Some electric motors typically include a stator and a rotor
having permanent magnets adhered thereto. Motor stators can be
formed by stamping laminations from a sheet, which results in
leftover material in the center of the stamping. This leftover
material can be further stamped into rotor laminations to construct
a rotor core. As such, utilizing the leftover material can provide
an economic savings compared to purchasing a rotor core
manufactured with steel tubing or powdered metal. However,
laminated rotor cores typically include gaps between the
laminations, which may allow moisture to travel through the gaps
and weaken the adhesive bond between the laminated rotor core and
the permanent magnets, resulting in magnet detachment and motor
failure. The systems and methods described herein provide a
laminated rotor with improved resistance to moisture exposure.
[0014] FIG. 1 is a perspective cut-away view of an exemplary
electric motor 10. Although referred to herein as electric motor
10, electric motor 10 can be operated as either a generator or a
motor. Electric motor 10 includes a first end 12, a second end 14,
and a motor assembly housing 16. Electric motor 10 also includes a
stationary assembly 18 and a rotatable assembly 20. Motor assembly
housing 16 defines an interior 22 and an exterior 24 of motor 10
and is configured to at least partially enclose and protect
stationary assembly 18 and rotatable assembly 20. Stationary
assembly includes a stator core 28, which includes a plurality of
teeth 30 and a plurality of windings 32 wound around stator teeth
30. Stator core 28 may include any number of teeth 30 that enables
motor 10 to function as described herein, for example, stator core
28 may have nine teeth. Furthermore, in an exemplary embodiment,
stator core 28 is formed from a stack of laminations made of highly
magnetically permeable material. Stationary assembly 18 may be a
round, segmented, or roll-up type stator construction and windings
32 are wound on stator core 28 in any suitable manner that enables
motor 10 to function as described herein.
[0015] Rotatable assembly 20 includes a permanent magnet rotor core
36 and a shaft 38. In the exemplary embodiment, rotor core 36 is
formed from a stack of laminations made of magnetically permeable
material. Rotor core 36 is substantially received in a central bore
of stator core 28 for rotation along an axis of rotation X. FIG. 1
illustrates rotor core 36 and stator core 28 as solid for
simplicity.
[0016] In the exemplary embodiment, electric motor 10 is coupled to
a fan or centrifugal blower (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. More specifically, motor 10 may be used in air moving
applications used in the heating, ventilation, and air conditioning
(HVAC) industry, for example, in residential applications using 1/5
horsepower (hp) to 1 hp motors. Alternatively, motor 10 may be used
in fluid pumping applications. Motor 10 may also be used in
commercial and industrial applications and/or hermetic compressor
motors used in air conditioning applications, where motor 10 may
have a rating of greater than 1 hp. Although described herein in
the context of an air handling system, electric motor 10 may engage
any suitable work component and be configured to drive such a work
component.
[0017] FIG. 2 illustrates exemplary rotatable assembly 20 having
rotor core 36 and shaft 38. Rotor core 36 includes a hub 40, a
rotor sleeve 42, and permanent magnets 44. Hub 40 includes an outer
periphery or diameter 46 and an inner periphery or diameter 48
coupled to shaft 38. Rotor sleeve 42 is formed from a plurality of
laminations 50 (shown in FIG. 3) and includes an outer periphery or
diameter 52 and an inner periphery or diameter 54, which is coupled
to hub outer diameter 46. Although described herein as
substantially circular, rotor sleeve outer and inner peripheries
52, 54 may have any suitable shape that enables motor 10 to
function as described herein. Laminations 50 are either interlocked
or loose and are fabricated from, for example, multiple punched
layers of stamped metal such as steel. Permanent magnets 44 are
coupled to rotor sleeve outer diameter 52 by any suitable adhesive
34 and, in the exemplary embodiment, rotor core 36 includes three
permanent magnets 44. Alternatively, rotor core 36 may include any
number of permanent magnets 44 that enables rotor core 36 to
function as described herein.
[0018] FIGS. 3 and 4 illustrate exemplary rotor sleeve 42 formed by
a stack of pressed laminations 50. Even though laminations 50 are
pushed close together, small gaps 56 remain between adjacent
laminations 50. In some environments, such as high humidity
environments, air and moisture may enter rotor core 36 and travel
from sleeve inner diameter 54 to sleeve outer diameter 52 via gaps
56. Air and moisture reaching sleeve outer diameter 52 (i.e., the
interface or bond area between sleeve outer diameter 52 and
permanent magnets 44) may degrade adhesive 34, thereby weakening
the bond between sleeve 42 and permanent magnet 44.
[0019] In the exemplary embodiment, a sealant 58 is applied in gaps
56 between adjacent laminations 50 to facilitate preventing air and
moisture from traveling through gaps 56 between sleeve inner
diameter 54 and sleeve outer diameter 52. As such, sealant 58 seals
gaps 56 and facilitates preventing air and moisture from reaching
adhesive 34 and affecting the bond between permanent magnets 44 and
sleeve 42. In the exemplary embodiment, sealant 58 is a material
such as a varnish, an anaerobic wicking grade thread locker, a
casting porosity sealant, a polyurethane, an ultraviolet light
curing sealant, a caulking or rubberized sealant, and/or an enamel
paint. Alternatively, sealant 58 may be any material that enables
rotor core 36 to function as described herein.
[0020] As shown in the cut-away view of FIG. 5, sealant 58 is
applied to substantially the entire gap 56 between sleeve inner
diameter 54 and sleeve outer diameter 52. Alternatively, sealant 58
is applied to only a portion of gaps 56 such that there is not a
fluid pathway from sleeve inner diameter 54 to sleeve outer
diameter 52 via gaps 56 (e.g., in a thin, continuous line around a
circumference of sleeve 42). As such, seal 58 blocks any passage
through gaps 56 between inner diameter 54 and outer diameter 52. In
the exemplary embodiment, any sealant 58 applied to sleeve inner
diameter 54 and/or sleeve outer diameter 52 is removed such that
there is substantially no sealant 58 on the surface of sleeve inner
diameter 54 and/or the surface of sleeve outer diameter 52. Removal
of some types of sealant 58 from these surfaces may facilitate
stronger rotor construction and/or adhesion of magnets 44 to sleeve
42. Alternatively, sealant 58 is applied to the surface of sleeve
inner diameter 54, the surface of sleeve outer diameter 52, or both
(not shown). As such, some types of sealants 58 may facilitate
stronger rotor construction and/or adhesion of magnets 44 to sleeve
42. In addition, as shown in FIG. 6, sealant 58 may be applied to
substantially the entire surface area of permanent magnets 44 to
further facilitate preventing air and moisture from reaching
adhesive 34. Further still, sealant 58 may be applied to
substantially the entire surface area of rotor core 36 to further
facilitate preventing air and moisture from reaching adhesive 34 or
other portions of rotor core 36.
[0021] A method of assembling rotor core 36 and rotor sleeve 42 is
described herein. A plurality of laminations 50 are stamped from a
blank (not shown) and stacked to form rotor sleeve 42 having outer
diameter 52, inner diameter 54, and gaps 56 between adjacent
laminations 50. Sealant 58 is applied to at least one of gaps 56 to
seal gaps 56 and prevent a passageway for air and moisture to
travel between sleeve inner diameter 54 and sleeve outer diameter
52. For example, sealant 58 may be sprayed into gaps 56 and/or
brushed into gaps 56. Alternatively, or in addition, sleeve 42 may
be dipped into a bath of sealant 58 and/or sleeve 42 may be rolled
in a shallow bath of sealant 58 to apply sealant 58 to gaps 56.
However, any suitable method for applying sealant 58 to gaps 56 may
be used that enables rotor core 36 to function as described herein.
In the exemplary embodiment, sealant 58 is applied to substantially
the entire gap 56 between sleeve inner diameter 54 and sleeve outer
diameter 52. In the exemplary embodiment, any sealant 58 remaining
on the surface of inner diameter 54 and/or the surface of outer
diameter 52 is removed such that substantially no sealant 58
remains on the surface of inner diameter 54 and/or the surface of
outer diameter 52. Alternatively, sealant 58 is applied to the
surface of inner diameter 54 and/or the surface of outer diameter
52 (or not removed). Sealant 58 is then dried and/or cured (e.g.,
heat cured, air cured, etc.) such that a permanent seal is formed
in gaps 56, the surface of sleeve outer diameter 52, and/or the
surface of sleeve inner diameter 54.
[0022] At least one permanent magnet 44 is coupled to sleeve outer
diameter 52 by adhesive 34, and sleeve 42 is coupled to hub 40 to
form rotor core 36. Shaft 38 is coupled to hub 40 to form rotatable
assembly 20. In addition, or alternatively, sealant 58 is applied
to substantially the entire surface area of permanent magnet 44
and/or substantially the entire surface area of completed rotor
core 36. The formed seal facilitates preventing air and moisture
from reaching adhesive 34 and degrading or weakening the bond
between permanent magnet 44 and rotor sleeve 42.
EXEMPLARY EXPERIMENT
[0023] Various laminated sleeve rotors were tested for long term
magnet retention. Different sealants were applied to laminated
sleeves, which were subsequently assembled into rotor cores with
magnets. Additionally, sealant was applied over magnets and exposed
rotor outer surfaces on different groups of rotor assemblies. Also
tested was an aluminum cast PSC style rotor with glued-on magnets.
Uncoated, laminated sleeve rotors and purchased solid sleeve rotors
were used as control groups. The rotors were subjected to a
thermal/humidity cycle and a spin test was then performed to
destruction rpm to compare performance among the rotor groups.
[0024] Laminated rotor sleeves were obtained and sorted into
groups. Group A sleeves were left uncoated as controls and sealants
were applied in various ways to sleeve Groups B through L. No
sealants were purposely left on the rotor core outside surfaces
because it was intended that the acrylic adhesive still adhere
directly to the rotor core surface and not to another material when
bonding the magnets. Sleeve Groups A through L were then assembled
into rotors. Solid sleeve control Group M rotors were also
assembled. Four additional groups of laminated sleeve rotors were
assembled: Groups N and P had sealant/coatings applied over the
magnets and rotor core exterior surfaces, Group CG was an
unmodified control group, and Group VB rotors were sealed in
plastic bags. Final Group Q was a quantity of PSC cast form G
aluminum rotors. All rotors were subjected to the thermal/humidity
cycling and spin tested.
[0025] The Group A laminated sleeve control group was tested and
resulted in one failure at 9660 rpm and the next highest failure at
3780 rpm. For comparison purposes to the other groups, 9660 value
was ignored in the Cpk and mean rpm calculations, which has the
effect of lowering the mean rpm, but raising the Cpk due to less
variability. The Cpk value and mean rpm for control Group A were
used as benchmarks to judge the effectiveness of sealants used for
test Groups B through L.
[0026] Group B sealant included Valspar.RTM. clear varnish thinned
with xylene and placed in a tray. Each sleeve was roll dipped,
which coated all exposed surfaces including the inner diameter. The
outer diameter surface was rolled on paper towels to substantially
remove the varnish, and scallops and end surfaces were wiped with
paper towels. The varnish was heat cured in a gas oven at
266.degree. F. for two hours.
[0027] Group C sealant included Loctite.RTM. 290, which is an
anaerobic wicking grade thread locker. The sleeves were rolled
through a shallow pool to wick material between the laminations.
The sleeves were left overnight for curing, then wiped with paper
towels to substantially remove uncured sealant from all external
surfaces.
[0028] Control Group CG rotors were built with laminated sleeves
from the same time frame as Group A, but were completed as rotor
assemblies immediately while Group A rotors were not assembled
until Groups B through L were completed (a time delay of several
weeks).
[0029] Group D sealant included Humiseal.RTM. UV40. The material
was brush painted on the sleeve inner diameter and cured with UV
light.
[0030] Group E sealant included Loctite.RTM. Resinol RTC, which is
a casting porosity sealant. Special equipment was used that
cleaned, vacuumed impregnated, cured, and re-cleaned the rotor
sleeves.
[0031] Group F sealant included United Duct Sealer.TM., which is a
high bond strength sealant for low to high pressure HVAC metal duct
systems. The sealant was applied from a caulking gun cartridge and
spread on the sleeve inner diameter.
[0032] Group G sealant included Sili-Thane.TM. 803, which is a
silicone and polyurethane sealant. The sealant was applied from a
caulking gun cartridge and spread on the sleeve inner diameter.
[0033] Group H sealant included Seymour.RTM. Rapid Seal, which is a
rubberized sealant. The sealant was applied from a spray can to the
sleeve inner diameter.
[0034] Group J sealant included Krylon.RTM. clear polyurethane. The
sealant was applied from a spray can to the sleeve inner diameter
and air dried.
[0035] Group K sealant included Dupli-Color.RTM. gray
filler/primer, which is an automotive filler/primer. The sealant
was applied from a spray can to the sleeve inner diameter.
[0036] Group L sealant included Glyptal.RTM. 1201 Red. The
un-thinned sealant was brush painted on the sleeve inner diameter
and air dried.
[0037] Control Group M included the solid sleeve control group. Two
rotors failed at 6600 rpm and 6900 rpm, respectively. Group M
rotors acted as control samples against test Groups B through L due
to similar vintage laminated rotor sleeves, magnet lots, glue lots,
and assembly and glue process time frames.
[0038] Group N sealant included Glyptal.RTM. 1201 Red. The rotor
assemblies were roll dipped in the sealant thinned with xylene, but
the sealant did not appear to wick into the magnet gaps to reach
the rotor sleeve. The rotor assemblies were rolled on towels to
remove excess sealant from the outer magnet surfaces.
[0039] Group P sealant included Valspar.RTM. varnish. The rotor
assemblies were roll dipped in sealant thinned with xylene. The
rotor assemblies were rolled on towels to remove excess sealant
form the outer magnet surfaces.
[0040] Group Q included production PSC form G aluminum cast
cores.
[0041] Group VB included rotor assemblies heat sealed in plastic
bags. The rotors were built at the same time as Control Group CG
and sealed with ambient air and humidity.
[0042] Group VB plastic bagged rotors had the best testing
performance. All rotors spun to 10,000 rpm without any magnet
retention failure. The rotors were in the same environmental
chamber as the other test groups, but were subjected only to the
temperature cycling because of the sealed bags. The rotor and shaft
surfaces were completely rust free after cycling, illustrating that
preventing high moisture exposure to the laminated sleeve and
adhesive greatly improves magnet retention.
[0043] Group M had the second best testing performance with two
rotors failing at 6600 rpm and 6900 rpm while the remainder spun to
10,000 rpm without failure. Performance was better than laminated
sleeve Control Group A, and since Groups M and A had similar magnet
lots, glue lots, and assembly and glue process time frames, the
performance difference was attributed to sleeve construction.
[0044] Sealants applied to laminated sleeves that were successful
in improving magnet adhesion included Groups B, C, E, L and J. The
remaining sealants either performed poorly or were not further
considered due to various issues. The testing concluded that the
bagged rotor Group VB demonstrated that high humidity/moisture is
the primary factor affecting magnet retention. Five groups of
sealants showed improvement over Control Group A.
[0045] As discussed above, adhesive bonds between permanent magnets
and laminated rotors may weaken or degrade after exposure to some
environments. The systems and methods described herein are directed
to laminated rotors with improved magnet adhesion and moisture
resistance. A sealant is applied into the gaps between adjacent
laminations to facilitate preventing air and moisture from
traveling through the gaps and affecting the adhesive bond. The
sealant may also be applied to other portions of the laminated
rotor or to the entire laminated rotor itself to facilitate sealing
the rotor and its components from the environment.
[0046] 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 languages of the claims.
* * * * *