00/90/00
`i
`
`Steven P. Shurtz
`312 321 4230 '
`
`E—mail SBShurtz@brinkshofer.com
`
`‘
`
`
`
`B R I N K S
`
`H O F E R
`“—
`
`G I L S O N
`
`& LI 0 N E
`
`A PROFESSIONAL CORPORATION
`
`“Express Mail” mailing label number EL594 257 797 US
`
`Date of Deposit March 5 2003
`
`-
`
`r
`
`March 5, 2003
`
`»
`
`Attn: Box Patent Application
`Commissioner for Patents
`
`Washington, DC. 20231
`
`Re:
`
`STATOR ASSEMBLY MADE FROM A
`
`MOLDED WEB OF CORE SEGMENTS
`AND MOTOR USING SAME
`
`Our Case No. 8864/33
`
`Dear Sir:
`
`'"TEUECTUAL PROPER" ATTORNEVS
`NBC TOWER - SUITE 3600
`455 N. CITYFRONT PLAZA DRIVE
`CHICAGO,
`ILLINOIS 60611-5599
`brinkshofer.com
`FAX 312621-4299
`~
`A
`TELEPHONE 312 321 420
`SAN JOSE, CA
`INDIANAPOLIS, IN
`ANN ARBOR, Ml
`ARLINGTON, VA
`
`0
`
`
`
`Enclosed is a specification, including claims and drawings, for a patent application, filed Via
`“Express Mail Post Office to Addressee” service to obtain a filing date pursuant to 37 C.F.R.
`§§ 1.10 and 1.53(b). The declaration and filing fee are not included at the present time.
`
`Sincerely,
`
`Steven P. Shurtz
`
`Reg. No. 31,424
`
`SPS : sr
`Enclosures
`
`
`
`Am. Honda V. IV 11 - IPR2018—00619
`
`PET_HONDA_1003—0001
`
`Am. Honda v. IV II - IPR2018-00619
`PET_HONDA_1003-0001
`
`

`

`
`
`"Express Mail" mailing label number
`
`EL 594 257 797 US
`
`Date of Deposit:
`
`March 5 2003
`
`Our Case NO. 8864/33
`
`IN THE UNITED STATES PATENT AND TRADEMARK OFFICE
`APPLICATION FOR UNITED STATES LETTERS PATENT
`
`INVENTOR:
`
`GRIFFITH D. NEAL
`
`TITLE:
`
`STATOR ASSEMBLY MADE FROM A
`MOLDED WEB OF CORE
`SEGMENTS AND MOTOR USING
`SAME
`
`ATTORNEYS:
`
`STEVEN P. SHURTZ
`
`REG. NO. 31,424
`BRINKS HOFER GILSON & LIONE
`PO. BOX 10395
`
`CHICAGO, ILLINOIS 60610
`
`(312) 321—4200
`
`Am. Honda V. IV 11 - IPR2018-00619
`
`PET_HONDA_1003 —0002
`
`Am. Honda v. IV II - IPR2018-00619
`PET_HONDA_1003-0002
`
`

`

`
`
`-1-
`
`STATOR ASSEMBLY MADE FROM A MOLDED WEB OF CORE
`SEGMENTS AND MOTOR USING SAME
`
`REFERENCE TO EARLIER FILED APPLICATION
`
`The present application is a continuation—in—part of Application Serial
`
`No. 09/798,511, filed March 2, 2001, and entitled Stator Assembly Made From
`
`A Plurality Of Toroidal Core Arc Segments And Motor Using Same, which is
`
`hereby incorporated by reference.
`
`FIELD OF THE INVENTION
`
`The present invention relates generally to a stator assembly used in a
`
`dynamoelectric machine such as a motor or a generator.
`
`It relates particularly
`
`to a spindle motor such as used in a hard disc drive, and to the construction
`
`and arrangement of a stator assembly made from a plurality of arc segments.
`
`BACKGROUND OF THE INVENTION
`
`Computers commonly use disc drives for memory storage purposes.
`
`Disc drives include a stack of one or more magnetic discs that rotate and are
`
`accessed using a head or read-write transducer. Typically, a high speed
`
`motor such as a spindle motor is used to rotate the discs.
`
`In conventional spindle motors, stators have been made by laminating
`
`together stamped pieces of steel. These stamped pieces of steel are
`
`generally circular in nature, but also have “poles" extending either inwardly or
`
`outwardly, depending on whether the rotor is on the inside or surrounds the
`
`stator. The stamped pieces are laminated together and then coated with
`
`insulation. Wire is then wound around the poles to form stator windings.
`
`An example ofa conventional spindle motor 1 is shown in FIG. 1. The
`
`motor 1 includes a base 2 which is usually made from die cast aluminum, a
`
`stator 4, a shaft 6, bearings 7 and a disc support member 8, also referred to
`
`as a hub. A magnet 3 and flux return ring 5 are attached to the disc support
`
`member 8. The stator 4 is separated from the base 2 using an insulator (not
`
`shown) and attached to the base 2 using a glue. Distinct structures are
`
`10
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`Am. Honda V. IV 11 - IPR2018-00619
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`PET_HONDA_1003-0003
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`Am. Honda v. IV II - IPR2018-00619
`PET_HONDA_1003-0003
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`

`

`
`
`formed in the base 2 and the disc support member 8 to accommodate the
`
`bearings 7. One end of the shaft 6 is inserted into the bearing 7 positioned in
`
`the base 2 and the other end of the shaft 6 is placed in the bearing 7 located
`
`in the hub 8. A separate electrical connector 9 may also be inserted into the
`
`base 2.
`
`Each of these parts must be fixed at predefined tolerances with respect
`
`to one another. Accuracy in these tolerances can significantly enhance motor
`
`performance.
`
`In operation, the disc stack is placed upon the hub. The stator
`
`1O
`
`windings are selectively energized and interact with the permanent magnet to
`
`cause a defined rotation of the hub. As hub 8 rotates, the head engages in
`
`reading or writing activities based upon instructions from the CPU in the
`
`computer.
`
`Manufacturers of disc drives are constantly seeking to improve the
`
`15
`
`speed with which data can be accessed. To an extent, this speed depends
`
`upon the efficiency of the spindle motor, as existing magneto-resistive head
`
`technology is capable of accessing data at a rate greater than the speed
`
`offered by the highest speed spindle motor currently in production. The
`
`efficiency of the spindle motor is dependent upon the dimensional consistency
`
`20
`
`or tolerances between the various components of the motor. Greater
`
`dimensional consistency between components leads to a smaller gap
`
`between the stator 4 and the magnet 3, producing more force, which provides
`
`more torque and enables faster acceleration and higher rotational speeds.
`
`The conventional method of forming stators has a number of
`
`25
`
`drawbacks. First, most steel is manufactured in rolled sheets and thus has a
`
`grain orientation. The grain orientation has an effect on the magnetic flux
`
`properties of the steel.
`
`In circular stamped pieces of steel, the grain
`
`orientation differs at different points around the circle. Compared from the
`
`radius line of the circle, the grain orientation is sometimes aligned along the
`
`30
`
`radius, sometimes transverse to it, and mostly at a varying angle to the radius.
`
`The un-aligned grain structure of conventional stators causes the magnetic
`
`Am. Honda V. IV 11 - IPR2018-00619
`
`PET_HONDA_1003 -0004
`
`Am. Honda v. IV II - IPR2018-00619
`PET_HONDA_1003-0004
`
`

`

`
`
`-3-
`
`flux values to differ in parts of the stator, and thus the motor does not have
`
`consistent and uniform torque properties as it rotates.
`
`Another drawback with using circular steel pieces is that, especially for
`
`inward facing poles, it has been difficult to wind the wire windings tightly
`
`because of the cramped space to work inside of the laminated stator core.
`
`The cramped working space creates a lower limit on the size of the stator and
`
`thus the motor. The limited working space also results in a low packing
`
`density of wire. The packing density of wire coiled around the poles affects
`
`the amount of power generated by the motor.
`
`Increasing packing density
`
`increases the power and thus the efficiency of the spindle motor.
`
`An important factor in motor design is to reduce stack up tolerances in
`
`the motor. Stack up tolerances reduce the overall dimensional consistency
`
`between the components. Stack up tolerances refer to the sum of the
`
`variation of all the tolerances of all the parts, as well as the overall tolerance
`
`that relates to the alignment of the parts relative to one another. One source
`
`of stack up tolerances is from the circular stator body. Generally, the
`
`thickness of rolled steel is not uniform across the width of the roll. Sometimes
`
`the edges are thicker or thinner than the center.
`
`In a stator made from
`
`circular stamped pieces, the thicknesses of individual laminations are thus
`
`different from one side to the other. When stacked together, this creates a
`
`stack up tolerance problem. Furthermore, the circular stampings leave a lot of
`
`wasted steel that is removed and must be recycled or discarded.
`
`Another important factor in motor design is the lowering of the
`
`operating temperature of the motor.
`
`Increased motor temperature affects the
`
`electrical efficiency of the motor and bearing life. As temperature increases,
`
`resistive loses in wire increase, thereby reducing total motor power.
`
`Furthermore, the Arhennius equation predicts that the failure rate of an
`
`electrical device is exponentially related to its operating temperature. The
`
`frictional heat generated by bearings increases with speed. Also, as bearings
`
`get hot they expand, and the bearing cages get stressed and may deflect,
`
`causing non-uniform rotation, reducing bearing life. This non—uniform rotation
`
`causes a further problem of limiting the ability of the servo system controlling
`
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`20
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`25
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`Am. Honda V. IV 11 - IPR2018-00619
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`PET_HONDA_1003 —0005
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`Am. Honda v. IV II - IPR2018-00619
`PET_HONDA_1003-0005
`
`

`

`
`
`-4-
`
`the read/write heads to follow data tracks on the magnetic media. One
`
`drawback with existing motor designs is their limited effective dissipation of
`
`the heat, and difficulty in incorporating heat sinks to aid in heat dissipation.
`
`In
`
`addition, in current motors the operating temperatures generally increase as
`
`the size of the motor is decreased.
`
`Manufacturers have established strict requirements on the outgassing
`
`of materials that are used inside a hard disc drive. These requirements are
`intended to reduce the emission of materials onto the magnetic media or
`
`heads during the operation of the drive. Of primary concern are glues used to
`
`attach components together, varnish used to insulate wire, and epoxy used to
`
`protect steel laminations from oxidation.
`In addition to such outgassed materials, airborne particulate in a drive
`
`may lead to head damage. Also, airborne particulates in the disc drive could,
`
`interfere with signal transfer between the read/write head and the media. To
`
`reduce the effects of potential airborne particulate, hard drives are
`
`manufactured to exacting clean room standards and air filters are installed
`
`inside of the drive to reduce the contamination levels during operation.
`
`An example of a spindle motor is shown in U.S. Patent No. 5,694,268
`
`(Dunfield et aI.) (incorporated herein by reference). Referring to FIG. 5 of this
`
`patent, a stator of the spindle motor is encapsulated with an overmold 42.
`
`The overmolded stator 40 contains openings through which mounting pins 44
`
`may be inserted for attaching the stator 200 to a base. U.S. Patent
`
`No. 5,672,972 (Viskochil) (incorporated herein by reference) also discloses a
`
`spindle motor having an overmolded stator. One drawback with the stators
`
`described in these patents is this difficulty in winding wire on the poles.
`
`Another drawback is the height of the lamination stacks. Further, the
`
`overmolds shown in these patents are not effective in dissipating heat or
`
`dampening some vibrations generated by energizing the stator windings.
`
`U.S. Patent No. 5,806,169 (Trago) (incorporated herein by reference)
`
`discloses a method of fabricating an injection molded motor assembly.
`
`However, neither the Trago design nor the other prior art designs address the
`
`problems of winding wire, variation in the thickness of steel used to make the
`
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`20
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`25
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`30
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`Am. Honda V. IV 11 - IPR2018-00619
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`PET_HONDA_1003—0006
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`Am. Honda v. IV II - IPR2018-00619
`PET_HONDA_1003-0006
`
`

`

`
`
`-5-
`
`stator cores and the non-uniform grain structure in the steel compared to the
`
`magnetic flux in the stator during operation of the motor.
`
`Some of these problems have been addressed by motor manufacturing
`
`methods in which individual stator arc segments are made and wound with
`
`wire to form poles, and these segments are then assembled to form a
`
`complete stator. While this process allows for higher packing density, it has
`
`several drawbacks. Somehow the individual segments have to be assembled
`
`and held in place to form the stator.
`
`In addition, the individual wires of the
`
`different poles have to be connected together for the poles that are of the
`
`10
`
`same phase. These numerous wires tend to get in the way during the
`
`assembly process, slowing down the manufacturing process.
`
`U.S. Patent No. 6,049,153 to Nishiyama describes the use of crimping
`
`or welding to attach segments together. This process deforms the steel and .
`
`reduces the level of magnetic flux produced by the laminations. The process
`
`15
`
`also requires numerous wire interconnections when the poles are wound as
`
`20
`
`25
`
`discrete components, and it does not offer improvements in wire routing.
`
`U.S. Patent No. 5,729,072 to Hirano describes the use of welding or an
`
`adhesive to hold the segments together. A disadvantage of this approach is
`
`that the stator poles must be handled as separate elements during stator
`
`construction. This requires complicated assembly equipment and a slow
`
`manufacturing process.
`
`U.S. Patent No. 6,265,804 to Nitta describes the use of plastic
`
`insulation in combination with segmented stators. This approach does not
`
`improve on the problem of how to assemble and hold the individual segments
`
`in place, nor does it aid in connecting the various wires.
`
`U.S. Patent No. 6,167,610 to Nakahara describes a method of making
`
`a rotary motor where a length of steel strip has thin portions between blocks
`
`of pole teeth. Wire is wound on the pole teeth while the steel strip is straight.
`
`Later the thin sections are bent to allow the poles to form a stator. One
`
`3O
`
`problem with this design is that when the thin portions are bent, the stress on
`
`the steel reduces the flux capacity of the connecting steel, forming the back
`
`iron. Also, the stamping of such a length of steel strip would be expensive
`
`Am. Honda V. IV 11 - IPR2018-00619
`
`PET_HONDA_1003—0007
`
`Am. Honda v. IV II - IPR2018-00619
`PET_HONDA_1003-0007
`
`

`

`
`
`-6—
`
`and result in large amount of scrap. Thus, a need exists for a method of
`
`making motors overcoming the aforementioned problems.
`
`BRIEF SUMMARY OF THE INVENTION
`
`A method of making stator assemblies has been invented which
`
`overcomes many of the foregoing problems.
`
`In addition, unique stator
`
`assemblies and other components of a motor have been invented.
`
`In one
`
`aspect. the invention is a stator assembly comprising a plurality of discrete
`
`stator segments each at least partially encased with a phase change material,
`
`wherein the phase change material also comprises a bridge between adjacent
`
`10
`
`segments to link adjacent segments into a continuous strip; and the linked
`
`stator segments being arranged and secured together to form the stator
`
`assembly.
`
`In a second aspect, the invention is a combination of stator arc
`
`segments and a flexible carrier used to link said stator arc segments during a
`
`15
`
`winding operation comprising: a) a plurality of stator arc segments; and b) a
`
`phase change material constituting said flexible carrier adhered to the stator
`
`arc segments which links said segments in a uniform and predetermined
`
`position with respect to one another.
`
`20
`
`25
`
`In another aspect the invention is a method of making a stator
`
`assembly comprising: a) providing at least two stator arc segments linked
`
`together by a phase change material and each constituting a pole and having
`
`a first side surface and a second side surface; b) winding wire on the poles; c)
`
`aligning said stator arc segments to form a toroidal core, wherein each said
`
`side surface of one segment is in contact with an opposing side surface of
`
`another segment; and d) substantially encapsulating said toroidal core with a
`
`monolithic body of phase change material to form said stator assembly.
`
`In another aspect the invention is a method of making a stator
`
`assembly comprising: a) providing at least two stator arc segments linked
`
`together by a phase change material and each providing a pole and having a
`
`Am. Honda V. IV 11 - IPR2018-00619
`
`PET_HONDA_1003—0008
`
`Am. Honda v. IV II - IPR2018-00619
`PET_HONDA_1003-0008
`
`

`

`
`
`-7-
`
`first side surface and a second side surface; b) winding wire on each pole of
`
`each arc segment; 0) aligning said stator arc segments to form a toroidal core,
`
`wherein each said side surface of one segment is in contact with an opposing
`
`side surface of another segment; and d) placing a retaining member on the
`
`exterior of the toroidal core to unitize the structure.
`
`In yet another aspect, the invention is a series of discrete stator
`
`segments each substantially encapsulated with, and linked together by
`
`bridges made from, an injection molded thermoplastic material.
`
`With the unique linked but discrete segment assemblies, wire can be
`
`wound around the poles with a high packing density, yet at the same time the ‘
`
`segments can be maintained in their proper order so that one continuous piece
`
`of wire can be used to wind all poles in the same series or phase, making it
`
`unnecessary to later connect wires from individual windings to one another. The
`
`invention provides the foregoing and other features, and the advantages of the
`
`invention will become further apparent from the following detailed description of
`
`the presently preferred embodiments, read in conjunction with the
`
`accompanying drawings. The detailed description and drawings are merely
`
`illustrative of the invention and do not limit the scope of the invention, which is
`
`defined by the appended claims and equivalents thereof.
`
`1O
`
`15
`
`20
`
`BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
`
`FIG. 1
`
`is an exploded, partial cross-sectional and perspective view of a
`
`conventional prior art high speed motor.
`
`FIG. 2 is perspective view of a stator arc segment being loaded into an
`
`injection mold prior to injecting a phase change material to make a limited
`
`series of stator arc segments of the present invention.
`
`FIG. 3 is a perspective, partial cross-sectional view of an encapsulated
`
`stator arc segment of FIG. 2.
`
`FIG. 4 is a perspective view of the encapsulated stator arc segment of
`
`FIG. 2.
`
`‘
`
`FIG. 5 is a perspective view of a series of encapsulated stator arc
`
`segments of FIGS. 2-4 linked together by a thermoplastic webbing.
`
`25
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`Am. Honda V. IV 11 - IPR2018-00619
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`PET_HONDA_1003—0009
`
`Am. Honda v. IV II - IPR2018-00619
`PET_HONDA_1003-0009
`
`

`

`
`
`*
`
`test
`
`1E93 Sn.)
`
`
`
`-8—
`
`FIG. 6 is a perspective view of the series of stator arc segments of
`
`FIG. 5 during wire winding.
`
`FIG. 7 is a perspective view of an injection molded stator assembly
`
`using the linked serial of webbed stator arc segments of FIG. 6.
`
`FIG. 8a is a cross—sectional view of a toroidal core made from the
`
`linked series of stator arc segments after the wire winding shown in FIG. 5 in
`
`an injection mold assembly, prior to injecting a phase change material.
`
`FIG. 8b is a cross-sectional view of the toroidal core of FIG. 8a in an
`
`injection mold assembly after injecting a phase change material, resulting in
`
`the stator assembly of FIG. 7.
`
`FIG. 9 is an exploded, partial cross-sectional and perspective view of a
`
`motor using the encapsulated webbed stator of FIG. 7.
`
`FIG. 10 is a perspective view of a stator assembly of a second
`
`embodiment of the present invention using a steel band to unitize the webbed
`
`stator arc segments.
`
`DETAILED DESCRIPTION OF THE DRAWINGS AND PREFERRED
`EMBODIMENTS OF THE INVENTION
`
`A preferred embodiment of a motor of the present invention and
`
`portions of the motor at different stages of manufacture are shown in FIGS. 2-
`
`7 and 9. The spindle motor 100 (FIG. 9) is designed for rotating 3 disc or
`
`stack of discs in a computer hard drive. Motor 100 is formed by using an
`
`injection molded stator assembly 40, that is formed by injection molding a
`
`plurality of stator arc segments 20 (FIG. 2) aligned to form a toroidal core 17
`
`(FIG. 7). Although the embodiment described here uses individual arc
`
`segments, one of ordinary skill in the art will understand that groups of two,
`
`three or any greater number of arc segments may be used. The preferred
`
`motor of the present invention may be smaller, has a grain structure that is
`
`more uniformly aligned. and allows for greater packing density of wire and
`
`reduces waste of steel in the manufacturing process, as compared with
`
`conventional motors, thereby increasing power and reducing stack up
`
`10
`
`15
`
`20
`
`25
`
`3O
`
`Am. Honda V. IV 11 - IPR2018-00619 ,
`PET_HONDA_1003—0010
`
`Am. Honda v. IV II - IPR2018-00619
`PET_HONDA_1003-0010
`
`

`

`
`
`_g-
`
`tolerances and manufacturing costs and producing other advantages
`
`discussed below.
`
`Referring to FIG. 2, a stator arc segment 20 is first constructed, using
`
`steel laminations 11. The stator arc segment 20 is made of steel pieces that
`
`are stamped out of rolled steel. The stamped steel pieces are arc segments,
`
`but also have a pole 21 extending inwardly or outwardly depending on
`
`whether the rotor is inside or surrounds the stator.
`
`In the embodiment shown
`
`in FIG. 2, the pole 21 is shown extending inwardly. The stamped pieces are
`
`then coated with encapsulating material 22 which provides electrical insulation
`
`and laminates the pieces together to form a stator arc segment 20, and links
`
`other arc segments into a continuous strip via webbing 23.
`
`The encapsulating material 22 is preferably formed of a phase change
`
`material, meaning a material that can be used in a liquid phase to envelope
`
`the stator, but which later changes to a solid phase. There are two types of
`
`phase change materials that will be most useful in practicing the invention:
`
`temperature activated and chemically activated. A temperature activated
`
`phase change material will become molten at a higher temperature, and then
`
`solidify at a lower temperature. However, in order to be practical, the phase
`
`change material must be molten at a temperature that is low enough that it
`
`can be used to encapsulate a toroidal core. Preferred phase change
`
`materials will be changed from a liquid to a solid in the range of about 200 0F
`
`to about 700 °F, more preferably in the range of about 550 °F to about 650 °F.
`
`The most preferred temperature activated phase change materials are
`
`thermoplastics. The preferred thermoplastic will become molten at a
`
`temperature at which it is injection-moldable, and then will be solid at normal
`
`operating temperatures for the motor. An example of a phase change
`
`material that changes phases due to a chemical reaction, and which could be
`
`used to form the body, is an epoxy. Other suitable phase change materials
`
`may be classified as thermosetting materials.
`
`As shown in FIG. 2 the segments 20 can be placed in a multi-cavity
`
`mold 28 to increase productivity.
`
`In the preferred embodiment the individual
`
`laminations 11 making up the segments are not interconnected but loosely
`
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`Am. Honda V. IV 11 - IPR2018-00619
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`PET_HONDA_1003—001 1
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`Am. Honda v. IV II - IPR2018-00619
`PET_HONDA_1003-0011
`
`

`

`
`
`-10-
`
`stacked together before insertion into the mold 28. After the thermoplastic
`
`solidifies, the overmolded segments are ejected from their cavities. New
`
`laminations are inserted into the cavities and the process repeats.
`
`In the
`
`preferred embodiment, a continuous strip of segments is formed by linking the
`
`webbing from successive molding operation. This is done by designing the
`
`tool to insert a section of the plastic webbing of the outermost segment
`
`molded in the prior cycle with the new laminations to be molded. When the
`
`plastic encapsulates the new segments it can mechanically lock with or,
`
`depending upon design, re-melt, the webbing from the prior cycle, thus
`
`making a continuous strip, as shown in FIG. 5. The series has segments 20
`
`with poles 21A, 21B and 21 C arranged next to one another as they will be in
`
`the finished stator assembly.
`
`The stator arc segments 20 are preferably molded into a continuous
`
`strip where the webbing acts as a carrier to link the segments together.
`
`In the
`
`preferred embodiment the encapsulating material 22 forms wire retaining
`
`flanges 24 to prevent wire from slipping off the pole.
`
`In a preferred
`
`embodiment, winding posts 25 as well as webbing 23 allow orientation of wire
`
`as it transfers across multiple poles.
`
`By precisely aligning the stator arc segments 20, the webbing 23 can
`
`also be used to guide the wire between common phase poles, thus
`
`eliminating the need for interconnections commonly used on segmented
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`stator motors. This greatly enhances the efficiency for winding wire 15 around
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`the poles 21 and significantly reduces the cost.
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`The webbing can be deflected to allow the gap between adjoining
`
`poles to be increased as is shown in FIG. 6. This allows wire 15 to be wound
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`around the poles 21 of the stator arc segments 20 using a fly winder 34 that
`has a set of needles 35. The wire 15 is wound around one pole 21 and is
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`then wound around another pole 21 in its phase until all poles 21 in the same
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`phase are wound with the same wire 15. Poles 21 in other phases are also
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`similarly wound. Having only arc segments, rather than a full toroidal core,
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`and spreading the spacing between the adjoining segments for needle 35 to
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`Am. Honda V. IV 11 - IPR2018-00619
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`PET_HONDA_1003—0012
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`Am. Honda v. IV II - IPR2018-00619
`PET_HONDA_1003-0012
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`“Si
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`wind wire 15 around poles 21, allows a wire packing density of more than 80
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`percent to be achieved.
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`A length of connected stator segments 20 corresponding to the number
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`of poles 21 required to produce the motor are cut from the continuous strip.
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`The strip is then rolled into a magnetically inducible toroidal core 17 having a
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`plurality of poles 21 thereon, and wire windings 15 which serve as conductors.
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`To form the toroidal core 17, a side surface 16 of each stator arc segment 20
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`is aligned and brought into contact with a corresponding side surface of
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`another stator arc segment 20.
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`In certain embodiments where a reduction in
`
`eddy currents is desirable, it may be preferable to separate faces 16. This
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`could be done by using a thin film of encapsulation material 22 over the side
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`surfaces 16, or the edges 19 of the insulator end surface (FIG. 4) could be
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`used to create the gap. The wire 15 between the poles 21 of different stator
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`arc segments 20 is also aligned in the toroidal core 17, following the arc of the
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`stator arc segments 20. As a result, the wire in the toroidal core 17 is taught.
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`As shown in FIG. 7, the toroidal core 17 is then encapsulated in a body
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`42. Together the toroidal core 17 and the body 42 make up an injection
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`molded stator assembly 40. The body 42 is preferably a monolithic body.
`
`Monolithic is defined as being formed as a single piece. The body 42
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`substantially encapsulates the toroidal core 17. Wires 44 extend out of the
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`body 42 for connection to the power source used to supply the motor.
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`Substantial encapsulation means that the body 42 either entirely surrounds
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`the toroidal core 17, or surrounds almost all of it except for minor areas of the
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`toroidal core 17 that may be exposed. However, substantial encapsulation
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`means that the body 42 and toroidal core 17 are rigidly fixed together, and
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`behave as a single component with respect to harmonic oscillation vibration.
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`The preferred method of developing the monolithic body 42 comprises
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`designing a phase change material to have a coefficient of linear thermal
`
`expansion such that the phase change material contracts and expands at
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`approximately the same rate as the metal laminations of the toroidal core 17.
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`For example, the preferred phase change material should have a CLTE of
`
`between 70% and 130% of the CLTE of the core of the stator. The phase
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`Am. Honda V. IV 11 - IPR2018-00619
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`PET_HONDA_1003-0013
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`Am. Honda v. IV II - IPR2018-00619
`PET_HONDA_1003-0013
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`change material should have a CLTE that is intermediate the maximum and
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`minimum CLTE of the toroidal core and other motor components where the
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`body is in contact with those other components and they are made of a
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`different material than the core. Also, the CLTE’s of the body and toroidal
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`core should match throughout the temperature range of the motor during its
`
`operation. An advantage of this method is that a more accurate tolerance
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`may be achieved between the body and the components of the toroidal core
`
`because the CLTE of the body matches the CLTE of the toroidal core
`
`components more closely. Most often the toroidal core components will be
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`metal, and most frequently steel and copper. Other motor parts are often
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`made of aluminum and steel.
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`Most thermoplastic materials have a relatively high CLTE. Some
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`thermoplastic materials may have a CLTE at low temperatures that is similar
`
`to the CLTE of metal. However, at higher temperatures the CLTE does not
`
`match that of the metal. A preferred thermoplastic material will have a CLTE
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`of less than 2 x 10'5 in/in/°F, more preferably less than 1.5 x 10‘5 in/in/°F,
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`throughout the expected operating temperature of the motor, and preferably
`
`throughout the range of 0-250°F. Most preferably, the CLTE will be between
`
`about 0.8 x 10'5 in/in/°F and about 1.2 x 10‘5 in/in/°F throughout the range of
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`0-250°F. (When the measured CLTE of a material depends on the direction
`
`of measurement, the relevant CLTE for purposes of defining the present
`
`invention is the CLTE in the direction in which the CLTE is lowest. However,
`
`if a material has a rate of expansion in one direction that is more than five
`
`times greater than the expansion rate in one of the other directions, then the
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`CLTE for purposes of defining the present invention is average of the CLTEs
`
`in each of the three X, Y and Z directions.
`
`The CLTE of common solid parts used in a motor are as follows:
`
`
`23°C
`250°F
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`Steel
`
`Aluminum
`
`Ceramic
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`0.5
`
`0.8
`
`0.3
`
`(x10‘5 in/in/°F)
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`0.8
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`1.4
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`0.4
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`Am. Honda V. IV 11 - IPR2018-00619
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`PET_HONDA_1003-0014
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`Am. Honda v. IV II - IPR2018-00619
`PET_HONDA_1003-0014
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`Of course, if the motor is designed with two or more different solids,
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`such as steel and aluminum components, the CLTE of the phase change
`
`material would preferably be one that was intermediate the maximum CLTE
`
`and the minimum CLTE of the different solids, such as 0.65 in/in/°F at room
`
`temperature and 1.1 x10'5in/in/°F at 250°F.
`
`One preferred thermoplastic material, Konduit OTF-212-11, which
`
`includes aluminum oxide as a filler at level of about 55%, was made into a
`
`thermoplastic body and tested for its coefficient of linear thermal expansion by
`
`It was found to have a CLTE in the range of—
`a standard ASTM test method.
`30 to 30°C of 1.09x10‘5 in/in/°F in the X direction and 1.26x10'5 in/in/°F in both
`
`the Y and Z directions, and a CLTE in the range of 100 to 240°C of 1.28x10'5
`
`in/in/°F in the X direction and 3.16x10‘5 in/in/°F in both the Y and Z directions.
`
`(Hence, the relevant CLTEs for purposes of defining the invention are
`1.09 x 10'5 in/in/°F and 1.28 x 10'5 in/in/°F.) Another similar material, Konduit
`
`PDX —0—988, was found to have a CLTE in the range of —30 to 30°C of
`1.1x10-5 in/in/°F in the x direction and 1.46x10'5 in/in/°F in both the Y and 2
`
`directions, and a CLTE in the range of 100 to 240°C of 1.16x10‘5 in/in/°F in
`
`the X direction and 3.4x10‘5 in/in/°F in both the Y and Z directions. By
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`contrast, a PPS type polymer, (Fortron 4665) was likewise tested. While it
`
`had a low CLTE in the range of —30 to 30°C (1.05X10'5in/in/°F in the X
`
`direction and 1.33x10‘5 in/in/°F in both the Y and Z directions), it had a much
`
`higher CLTE in the range of 100 to 240°C (1 .94x10'5 in/in/°F in the X direction
`
`and 4.17x10'5 in/in/°F in both the Y and 2 directions).
`
`In addition to having a desirable CLTE, the preferred phase change
`
`material will also have a high thermal conductivity. A preferred thermoplastic
`
`material will have a thermal conductivity of at least 0.4 watts/meter°K using
`
`ASTM test procedure 0149 and tested at room temperature (23°C).
`
`In the present embodiment, the phase change material used to make
`
`the body 42 is preferably a thermally conductive but non—electrically
`
`conductive plastic.
`
`In addition, the plastic preferably includes ceramic filler
`
`particles such as aluminum oxide or boron nitride that enhance the thermal
`
`conductivity, while reducing the coefficient of linear thermal expansion of the
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`Am. Honda V. IV 11 - IPR2018-00619
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`PET_HONDA_1003 -00 1 5
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`plastic. The filler will preferably comprise about 30% or more of the phase
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`change material, more preferably about 45% or more, and most preferably
`
`about 55% or more. A preferred form of plastic is polyphenyl sulfide (PPS)
`
`sold under the tradename “Konduit” by LNP. Grade OTF-212—11 PPS is
`
`particularly preferred, using a roughly 55 weight percentage of aluminum
`
`oxide as a filler. Examples of other suitable thermoplastic resins include, but
`
`are not limited to, thermoplastic resins such as 6,6-polyamide, 6-polyamide,
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`4,6-polyamide, 12,12-polyamide, 6,12-polyamide, and polyamides containing
`
`aromatic monomers,