U.S. patent application number 10/064584 was filed with the patent office on 2002-12-05 for method of manufacturing electric machines using kinetic spray.
This patent application is currently assigned to Ford Motor Company. Invention is credited to Ginder, John Matthew, Leonardi, Franco, McCune, Robert Corbly.
Application Number | 20020182314 10/064584 |
Document ID | / |
Family ID | 24736543 |
Filed Date | 2002-12-05 |
United States Patent
Application |
20020182314 |
Kind Code |
A1 |
Leonardi, Franco ; et
al. |
December 5, 2002 |
Method of manufacturing electric machines using kinetic spray
Abstract
A method of manufacturing electric machines comprising the steps
of kinetically spraying a powdered admixture of magnetic material
and ductile binder material on to a substrate and applying a
concentrated magnetic field to the sprayed admixture to cause
magnetic dipole alignment in the sprayed admixture. The magnets of
the present invention may be integrally formed atop carriers to
form electrical machines such as motors, generators, alternators,
solenoids, and actuators. The manufacturing techniques used in this
invention may produce highly defined articles that do not require
additional shaping or attaching steps. Very high-purity permanent
and soft magnetic materials, and conductors with low oxidation are
produced.
Inventors: |
Leonardi, Franco; (Dearborn
Heights, MI) ; Ginder, John Matthew; (Plymouth,
MI) ; McCune, Robert Corbly; (Southfield,
MI) |
Correspondence
Address: |
FORD GLOBAL TECHNOLOGIES, INC
SUITE 600 - PARKLANE TOWERS EAST
ONE PARKLANE BLVD.
DEARBORN
MI
48126
US
|
Assignee: |
Ford Motor Company
Dearborn
MI
|
Family ID: |
24736543 |
Appl. No.: |
10/064584 |
Filed: |
July 29, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10064584 |
Jul 29, 2002 |
|
|
|
09681733 |
May 30, 2001 |
|
|
|
Current U.S.
Class: |
427/128 ;
427/427 |
Current CPC
Class: |
H01F 41/16 20130101;
Y10T 428/12014 20150115; Y10T 428/12063 20150115; Y10T 428/12583
20150115; Y10T 428/12465 20150115; Y10T 428/12493 20150115; Y10T
428/2984 20150115; Y10T 428/1275 20150115; Y10T 428/12757 20150115;
H02K 15/03 20130101 |
Class at
Publication: |
427/128 ;
427/427 |
International
Class: |
B05D 005/12; B05D
001/02 |
Claims
1. A method of manufacturing electric machines comprising the steps
of: kinetically spraying a powdered admixture of magnetic material
and ductile binder material on to a substrate; and applying a
concentrated magnetic field to said sprayed admixture to cause
magnetic dipole alignment in said sprayed admixture.
2. The method of claim 1, wherein said binder material is selected
from the group comprising iron, nickel, cobalt or alloys
thereof.
3. The method of claim 1, wherein said magnetic material is
selected from comprising iron, nickel, cobalt, samarium-cobalt
(SmCo.sub.5, Sm.sub.2Co.sub.17), AlNiCo, neodymium iron boron
(Fe.sub.14Nd.sub.2B), samarium iron nickel (SmFeNi).
4. The method of 1 wherein the volume fraction of the ductile
binder is between 10 and 80% of the sprayed admixture.
5. The method of 1 wherein the ductile binder material is magnetic
particles individually coated with eddy current resistant
films.
6. The method of claim 5, wherein the films are selected from the
group comprising oxide films, organic films and polymeric
films.
7. The method of 1 wherein the substrate accepting the permanent
magnet sprayed admixture is a soft magnetic material that
internally directs magnet flux.
8. The method of claim 1 wherein the kinetic spraying occurs at a
temperature substantially below the melting temperature of the
magnetic material, and said kinetically sprayed admixture adheres
to said carrier.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 09/681,733, filed May 30, 2001, entitled "Method Of
Manufacturing Electromagnetic Devices Using Kinetic Spray".
BACKGROUND OF INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method of manufacturing
electric machines including motors and generators using kinetic
spraying metal forming. More specifically, the present invention is
directly related to a method of manufacturing both conductive
metallizations, as well as permanent and soft magnets by applying
highly-defined, high-velocity sprays of conductors and magnetic
materials in powder form to an appropriate carrier without the need
for additional molding, shaping, sintering or tooling steps.
[0004] 2. Description of the Related Arts
[0005] "Electric machines" in the broadest sense, are fabricated
from specialized arrangements of conductive coils, magnetic
materials, supporting structures, and ancillary components such as
fasteners, wires, and other conductors.
[0006] Most "permanent" magnets and some "soft" magnets are
produced through a molding and sintering operation from an
admixture of magnetic materials and appropriate binders in an
initially powdered form, wherein the final shape of the particular
magnet is dictated by the mold tooling used. Additionally,
"permanent" magnets must be magnetized by exposing the magnet to
sufficiently high magnetic fields so as to introduce a strong,
semi-permanent magnetic alignment of individual magnetic dipoles
and larger physical domains. "Soft" magnetic materials, usually
predicated on iron and several of its alloys, are often fabricated
from sintered powders or laminated sheets, produced such that the
intrinsic magnetic moment for the material is not permanent, but
rather is determined by the magnitude of the applied field. Coils
made predominantly from copper wire are used both to generate
magnetic fields and electromagnetic torque in the airgap, with the
ultimate goal to generate motion, as in an electric motor, or to
generate electric power as in a generator or alternator. Electric
machines, which may be either generators or motors, are thus
assembled from specific geometric arrays of coils, magnetic
materials and supporting structures or carriers. Assembly processes
for electric machines involve attachment of magnets, laminations
and coils to housings designed to receive the magnet. When multiple
magnets are assembled, it becomes difficult to precisely align and
attach each magnet to the article or housing. A process that
eliminates the molding, hardening and assembly steps greatly
simplifies the construction process and reduces the cost and
complexity of the resultant article. Moreover, by supplying the
constituent materials of the particular electric machine as
"coatings" in contrast to separate three-dimensional structures, it
is possible to realize new and different electric machines,
fabricated by an unconventional process onto heretofore unused
carriers or platforms.
[0007] It is possible to thermal spray magnetic materials onto a
carrier as described in U.S. Pat. No. 5,391,403 ('403). This
thermal spray process has been used where relatively weak magnetic
fields are sufficient such as for use in a sensor. The method
described in the '403 patent is capable of producing very thin
magnetic coatings between 100-200 .mu.m in thickness. This coating
was made from magnetic oxides of iron, cobalt and nickel. The
intense heat from the thermal spray process causes the base metals
to oxidize and produce oxides. The oxides produce much weaker
magnetic fields than the base metals from which they originate.
They lack the capacity to produce sufficiently strong fields
required for motors and generators. The present invention is
directed to a method of producing magnets from base metals that are
capable of producing strong magnetic fields.
[0008] U.S. Pat. No. 4,897,283, teaches a method of producing
aligned permanent magnets by a high temperature plasma thermal
spray of samarium-cobalt. Auxiliary heat is applied before, during
and after the thermal spray to produce the magnet.
[0009] Because the deposition is conducted in an
environmentally-controlle- d chamber, oxidation of the metallic
alloy is expected to be minimal. Masking is optionally used to
produce fine deposition features, as is well-known in the
thermal-spray art. The temperature needed to produce the plasma
spray degrades the magnetic properties of the resulting
article.
[0010] Thermal spray has the advantage of being capable of rapidly
producing a layer of bulk material atop a carrier, but the heat
needed to create the molten metal droplets can alter the magnetic
properties of the sprayed material. Another family of thermal spray
technologies that does not use high temperatures for producing
molten droplets is collectively known as kinetic spraying. One
kinetic spray technique predominantly used to date has been that of
cold gas-dynamic spraying or "coldspray". The technique described
in U.S. Pat. No. 5,302,414 incorporated herein by reference, ('414)
uses a nozzle whose acceleration and focusing properties are
determined by gas dynamics and geometry to produce a jet of solid
or semi-solid particles that impinge onto a deformable substrate
material, typically metal. The particles have a size range of
approximately 1-50 micrometers. The particles are introduced under
pressure into a supersonic gas stream created through use of a
converging-diverging (deLaval) nozzle. The particles, once
accelerated to near supersonic velocities, impact on a collecting
substrate where they form a thick deposit, by a process believed to
be similar to explosive compaction or mechanical plating. The
coating may be applied for a number of purposes such as corrosion
or wear resistance. The '414 patent, states that the application
method may be used for electrically or magnetically conducting
coatings. However, the '414 patent does not provide examples of
electrically or magnetically conductive coatings. The methods
described all produce very thin (<400 .mu.m) coatings. These
coatings are generally too thin to be of use as magnets such as
those typically found in electric machines. The present invention
is directed to the application of bulk material to produce magnets
capable of creating magnetic fields useful in motors, generators
and similar devices.
[0011] The invention described herein utilizes the "cold spray"
process to produce electric machine elements as "coatings" or
deposits on an appropriate substrate or carrier. While the '414
patent discloses electrical and magnetic materials, it does not
provide for a methodology for permanent magnet deposits, composite
magnets, deposition conditions, properties of soft magnetic
materials, or suggested geometries for planarized or
`coating-based` electric machines.
SUMMARY OF INVENTION
[0012] The present invention is directed to a method of
manufacturing magnets using a kinetic-spray process where the
magnetic material is not exposed to high temperatures. This reduces
the formation of unwanted oxides and enables the precise build-up
of material atop a carrier into the final desired shape of the
magnet. The process utilizes a high-speed kinetic spray propelling
a fine metal powder to a target carrier. The metal powder has a
ductile component. The mixture adheres to the carrier, generally by
a mechanical attachment or metallurgical bond. The ductile
component serves as the bonding site for subsequent layers of
kinetic spray. The ductile material bonds to the ductile material
of the previous layers. The kinetic spray process or "cold"
gas-dynamic spraying enables the deposition of soft magnetic
materials with improved magnetic properties compared to those
produced by high-temperature thermal spraying based on arcs,
plasmas or flames. Additionally, the invention provides for the
formation of planar electrical coils using the same technology,
such that entire classes of electric machines can be fabricated
using a single spray technology. It will be apparent to those
skilled in the art that in addition to cold-spray deposition, other
kinetic spray processes may also be used to produce the low
temperature, highly-focused deposition such as electrically pulsed
plasmas as shown in U.S. Pat. No. 6,001,426, issued Dec. 14,1999,
tribo-acceleration as shown in U.S. Pat. No. 5,795,626, issued Aug.
18, 1998, and rail gun plasma acceleration.
BRIEF DESCRIPTION OF DRAWINGS
[0013] FIG. 1 is a diagram of a kinetic cold-spray apparatus that
may be used in the preparation of permanent magnets.
[0014] FIG. 2 is a cross-sectional view of hard and soft magnetic
materials applied atop a carrier by cold spraying.
[0015] FIG. 3 is a perspective view of a cold spraying device
producing a complex article.
[0016] FIG. 4 is a perspective view of an article produced by cold
spray.
[0017] FIG. 5 is an electric machine made using a soft magnetic
carrier to direct the magnetic flux from the permanent magnets
through a planar coil.
DETAILED DESCRIPTION
[0018] The present invention will be described through a series of
drawings, which illustrate the manufacture of a permanent magnet
motor. Other items such as generators, solenoids, actuators and
sensors may be manufactured using the same or similar technique and
equipment and are included within the invention described herein.
The following elements are a word list of the items described in
the drawings and are reproduced to aid in understanding the
invention:
[0019] 10 cold-spray system
[0020] 12 powder feeder
[0021] 14 high pressure gas inlet
[0022] 16 heater
[0023] 18 powder feed tube
[0024] 20 enclosure
[0025] 22 supersonic nozzle
[0026] 24 carrier
[0027] 26 bulk material
[0028] 28 permanent magnet material
[0029] 30 soft magnetic binder material
[0030] 32 coil
[0031] 34 electrical contact
[0032] 36 permanent magnet array
[0033] 38 planar coil
[0034] 40 motor
[0035] 42 support
[0036] 44 core
[0037] 46 insulator
[0038] 48 armature core
[0039] 50 magnetic flux
[0040] The invention is a manufacturing method for producing
permanent magnets. The permanent magnets that are the subject of
this invention have a sufficient magnetic strength to be used in
motors and generators and are generally referred to a `strong
magnets`. They are distinguished from `weak magnets` that may be
used for sensors and memory storage devices. Preferably, the
magnets are produced in the final desired shape without additional
hardening or shaping steps. The magnets are formed in layers
directly atop a carrier. Preferably, the carrier is the housing,
spindle or other device which utilizes the magnet. The invention
will be described as a method of making a magnet that will be used
in an electric motor. Other devices that utilize magnets may be
made using the same equipment, material and techniques as are
taught herein such as generators, alternators, solenoids, actuators
or sensors.
[0041] The equipment used for the manufacture of permanent magnets
may also be used to create electrical traces, electrical coils and
wiring. In this fashion, complete electric machines may be
fabricated using a cold-spray gun, or similar kinetic deposition
processes, by alternately producing the permanent magnet components
and then the electrical wiring and coils as will be more completely
described.
[0042] The kinetic spray process utilizes a cold-spray system 10.
The system 10 includes a powder feeder 12. The power feeder 12
supplies the powder materials for kinetic spraying. A high pressure
gas 14 propels the powder. A heater 16 heats the gas to a
temperature much less then the melting point of the powder. The
powder is directed through a powder feed tube 18 to the high
pressure chamber of a supersonic nozzle 22. The nozzle 22 propels
the powder particles at a carrier 24. The particles are deposited
atop the carrier 24 as a bulk build-up of material 26.
[0043] Illustrated in FIG. 2 is a schematized cross-sectional view
of the metallurgical microstructure of a magnet produced by the
cold-spray process. The carrier 24 may be either a non-magnetic or
soft magnetic material. Aluminum was found to be a good carrier
material because it is not ferromagnetic and provides a ductile
striking surface that enables the powdered metal to adhere to the
aluminum surface.
[0044] Aluminum does not, however, provide a low reluctance flux
return path needed in high energy-density motor/generator
applications. Iron would provide a preferred substrate in these
applications. The bulk material 26 is an admixture of the powders
that are sprayed atop the carrier 24. The bulk material 26
preferably includes a permanent magnet material 28 and a soft
magnetic binder material 30. The selection of the cold-spray
materials includes both magnetic and conductive materials as
described below. The magnetic composite 26 utilizes a ductile, soft
phase such a high-purity iron as a binder to effectively provide
both a mechanical interlocking of second phase magnetic particles,
as well as a metallurgical bond at the atomic level in some
instances (e.g. when the interleaving particle structures are not
interrupted by porosity, contamination or non-adhering oxide
phases. In general, the precise type of interparticle bonding will
be a function of the material types employed, their degree of
purity, and the conditions under which the compact is formed.
[0045] Materials
[0046] Magnetic Binder and `Soft Magnet` Materials.
[0047] Iron is the principal ingredient of "soft" magnetic
materials that effectively act as a conduit for controlling
direction, strength, and storage of magnetic fields. Desirable
physical properties are high internal purities and controlled
interfaces in bulk aggregates or pieces to minimize core losses
that occur as magnetization is propagated through the material. In
such devices as transformer cores, this is achieved through use of
insulated lamination layers of sheet electrical steel. In compacted
irons or powder-metallurgy materials, this is effected on a smaller
scale through use of soft-iron powders with polymeric or lubricant
coatings and metal surfaces with developed oxide layers. Cold
spraying of relatively pure iron such as Ancorsteel.TM. 1000
produced by the Hoeganaes Corporation, results in a soft magnetic
material with a density of approximately 7.46 g/cm3 compared to a
density of 7.86 g/cm3 for bulk pure iron. Saturation magnetization
of cold-sprayed Ancorsteel.TM. 1000 iron was found to be 1.98 Tesla
compared to 2.15 Tesla for pure iron. Cold-spraying conditions
which produced this material were achieved with pure helium gas at
an inlet temperature of 325-360.degree. C., a gas pressure of 300
psi (2.1 MPa), and iron particle sizes as sieved to -325 mesh,(max
particle approximately 45 micrometers). A thermal spray sample of
plain 0.8 carbon steel produced by twin-wire arc process in
comparison to the cold spray material showed lower density (6.98
g/cm3) and an appreciably poorer saturation magnetization of
approximately 1.52 Tesla and quasi-static energy loss of 2.1
J/kg/cycle vs. 1.8 J/kg/cycle for the cold-sprayed iron material.
These measurements suggest that the cold-spray iron material is
greatly superior to conventional thermally-sprayed carbon steels
when comparing its ability to be magnetized.
[0048] Core losses for cold-sprayed irons, which would dictate
higher-frequency energy losses in applications such as motors and
transformers, may be reduced through compaction of powder materials
having oxide or polymeric shells, with nominally pure iron in the
material core. An example of such a material is SomaloyT.TM. 500 of
H {dot over (o)} gan s Corporation. These powders are generally
formed into magnetic materials through warm compaction processes
such as those used in powder metallurgy, however, cold spraying
permits development of surface deposits of soft magnetic material
without use of separate tooling, thus permitting a variety of
structures to be implemented on the appropriate surface.
[0049] It is possible to reduce the core loss of the sprayed
magnetic material by providing resistance to eddy current flow
between adjacent particles of binder material. This effect may be
achieved by coating individual binder particles with an eddy
current resistant coating such as oxide films, organic films and
polymeric films.
[0050] Permanent Magnet Materials.
[0051] The second ingredient for a range of electromagnetic devices
to be fabricated by cold-spraying processes is a permanent magnet
deposit. Since cold-sprayed iron forms a soft magnet having a
saturation magnetization approaching that of pure iron, it is
possible to form a permanent magnet from the pure iron material by
exposure to high magnetic fields. This process is used to produce
conventional cast iron magnets for low-cost, low-performance
applications. Alternatively, improved and higher strength permanent
magnets in layer or coating form can be developed through a manner
of the cold spray process in which a composite structure is
achieved by spraying an admixture of a permanent magnet material
powder (e.g. neodymium-iron-boron (Fe14Nd2B), AINiCo, Sm--Co5) and
suitable ferromagnetic binder such as pure iron, nickel or cobalt,
which are known to be sprayable by the cold-gas or related process.
Layers so deposited will be in a non-magnetic condition, so it will
be necessary as a process step to use high magnetic fields to
induce a permanent magnet moment in the resulting structure.
[0052] A composite microstructure may be obtained by cold-spraying
an admixture of permanent magnet material and soft magnetic binder.
Such composite microstructures containing hard embedded phases in
soft ductile materials such as high-purity iron or nickel have been
demonstrated for carbides in a nickel-chromium alloy matrix in a
paper by McCune, R. C., A. N. Papyrin,J. N. Hall, W. L. Riggs, II
and P. H. Zajchowski, "An Exploration of the Cold Gas-Dynamic Spray
Method for Several Materials Systems," Advances in Thermal Spray
Science and Technology, Proc. 8th. National Thermal Spray
Conference, C. C. Berndt and S. Sampath, Eds., ASM Int'l., 1995 p
1-5, and incorporated herein by reference. The amount of binder
phase necessary to develop robust composites is approximately 50%
by volume and is believed to be a function of the plasticity of the
permanent magnet material; less binder phase being required for
more ductile materials. A minimum amount of "ductile phase"
required to form a permanent magnet deposit is on the order of
10-15% by volume of the softer phase. High-purity nickel is
immediately substitutable for iron in these compacts, and it is
believed that cobalt would also be readily usable as a binder at
particle velocities greater than those used for iron or nickel.
[0053] The present invention produces strong magnetic materials
have very low content of oxides; less than 5% by volume. This low
oxide concentration produces strong magnets that better retain a
permanent magnetic dipole alignment and produce stronger magnetic
fields.
[0054] Copper.
[0055] The third element of electromagnetic devices is a copper (or
other high-conductivity metal) winding. Copper is used for
connection points or pads and for making coil elements in both
motor and generator configurations. The cold spray copper deposit
is developed from high purity, (preferably <0.25% wt oxygen
content) inert gas-atomized copper powder with an optimum particle
size range between 10 and 30 micrometers. In the cold-gas spray
method, copper is deposited at a gas pressure of 2-2.4 MPa (280-340
psi) using dry nitrogen gas, with gas preheat conditions of
300-325.degree. C. Nozzles may be configured to provide metal
deposits having widths as small as 1 mm. Deposit thickness of as
much as 3-5 mm are possible for larger metallization widths (e.g.
10 cm). Other metals having good electrical conductivity and
particle plasticity will be apparent, including silver, gold and
aluminum of purities greater than 99%. Alloyed or so-called
dispersion-strengthened metals of comparable electrical
conductivity are also candidate materials for the electrical
metallization or coil structures.
[0056] Illustrated in FIG. 3 is a typical deposition arrangement
for a cold-spray magnet, wherein the sprayed material is directed
through the supersonic converging/diverging nozzle 22 is applied to
an aluminum carrier 24 at short (<2.5 cm) standoff distance from
the nozzle end. By manipulating the carrier in its own plane or by
manipulating separately the nozzle, it is possible to "draw" traces
TF of any dimension. The thickness of the deposit at any position
is governed by the residence time during which the spray is
maintained at any given X-Y position of the substrate or nozzle.
FIG. 3 shows a rectangular nozzle, which is optimized for the
cold-gas spray process, although it will be appreciated that other
nozzle geometries or entire nozzle arrays may be constructed to
produce patterns as can be designed.
[0057] In addition to producing a basic permanent magnet, the
invention enables the production of electric machines such as
motors, generators, alternators, solenoids and actuators. The basic
method is thus described in terms of a patternable arrangement of
conductors, bulk material of hard and soft magnetic materials on
appropriate substrates for generation of electromagnetic
elements.
[0058] Electric motors and generators are identical in terms of
manufacturing and construction and differ mainly in their function,
being often referred to commonly as "electric machines". In some
cases an electronic converter is used as an interface between the
power supply (typically either the electrical power grid or a
battery) and the electric machine. It is often the configuration of
this conversion device that determines whether the electric machine
in question will operate as a motor, a generator ("alternator" in
most automotive applications) or both.
[0059] An electric machine is typically composed of two types of
elements, that can be arbitrarily placed on the rotating element
(the "rotor") or the stationary element (the "stator"). These two
elements constitute a field-producing element called the
"excitation" and a torque-producing element called the "armature".
The latter is most typically a polyphase winding, comprised of
several coils properly connected. The "excitation" can be provided
by a coil, a multiplicity of coils or by a permanent magnet
array.
[0060] Illustrated in FIG. 4 is an electrical coil 32 made using
the same cold-spray process described. A copper electrical contact
34 is deposited as the bulk-material.
[0061] This construction may be used to fabricate the coil portion
of the motor.
[0062] Illustrated in FIG. 5 is a cross-sectional view of a
spray-deposited permanent magnet array 36 and a planer coil 38
produced by the method described above. If the coil 38 is
integrally assembled with the moving element or "rotor", then the
electrical EMF must be extracted through some type of mechanical
commutator arrangement which is well-known in the art (e.g., DC
motor/generator). Alternatively, the moving permanent magnet array
can be envisioned with a stationary coil set obviating the need for
a commutator (e.g., brushless permanent magnet motor/generator). It
will be apparent that integral permanent magnets developed by a
simple spray process could be incorporated into various moving
features of the motor with planar coils arranged adjacently to
extract electrical power as required, or to produce resultant
forces which could act as a braking or accelerating elements.
[0063] The motor 40 is made from a support 42 secured to the core
44. Depending on the physical requirements of the motor 40, the
support 42 may be eliminated. This is useful if the permanent
magnets 36 are directly applied to a motor component such as the
motor housing or the rotor. The core 44 may be optimized to conduct
the magnetic flux 50. Materials such as cast iron and steel are
suitable conduits for the magnetic flux between the permanent
magnets 36. Assemblies can be produced that take advantage of
magnetically-soft, rotating articles in a vehicle, such as the
engine flywheel, to act as the carrier. The carrier 44 directs the
magnetic flux 50 between adjacent magnets 36, where the magnetic
flux lines penetrat the area defined by the coil 38 are enhanced by
the underlying soft magnetic material of the carrier. Electrical
insulation 46 between the coil 38 and the armature core 48 isolates
the coil 38. from the armature core 48. It will also be apparent
that the magnetic flux 50 penetrating the area defined by the coil
38, can also be greatly enhanced through a symmetric arrangement of
magnets on either side of the coil 38. The concentration of
magnetic flux lines by the judicious arrangement of soft magnetic
elements will increase the effective power density of an electric
machine employing this construction.
[0064] In some cases both field and armature functions are combined
into a single stationary winding and the rotating element is shaped
in order to create a saliency in the magnetic circuit (e.g.,
synchronous reluctance and switched reluctance machines). The
saliency provides a preferred path for the magnetic flux to flow
and creates the opportunity to generate reluctance torque. This
type of machine is often considered the simpler to build, since the
rotating element is a single medium, passive device.
[0065] High-velocity, cold spray deposition processes provide a
means to produce electromagnetic design elements in robust,
planarized form on inert substrates such as metals with insulating
coatings, ceramics or polymers. Such devices can allow for simple
motors and generators or alternators to be fabricated on the
surfaces of other devices, or as free-standing appliances.
Planarized starter/alternators for example could be envisioned that
offer unique packaging opportunities. Alternatively, one could
imagine miniature "generators" built into braking system surfaces
for regenerative energy recovery. By effectively "printing" these
devices using cold spray depositions, the manufacturing costs could
be reduced from current means while also being adapted to the
mechanical systems at hand.
[0066] The invention has been described as a method of fabricating
permanent magnets, soft magnetics and electrical conductors in the
form of patterned deposits on supporting structures. While the best
modes for carrying out the invention have been described in detail,
those familiar with the art to which this invention relates will
recognize various alternative designs and embodiments for
practicing the invention as defined by the following claims.
* * * * *