DIE ASSEMBLY AND METHOD FOR MANUFACTURING WOUND MOTOR LAMINATED ARTICLE
A metal article, such as a stator core, is formed from a continuous strip of wound sheet stock material including winding slot cutouts. The winding slot cutouts are maintained at a substantially constant width throughout most of the radial extent of the winding slots in the finished article, except that one or more of the first and/or last wound layers (i.e., the radially innermost and radially outermost layers) may define winding slot cutouts that are wider than the other winding slot cutouts. Several radial layers may define cutout widths that are progressively expanded such that the resulting winding slot has terminal ends with edges that defining a stair-step profile that approximates a “radiused” or rounded edge. This rounded edge profile protects windings projecting radially into or outwardly from the winding slots near the edge of such slots.
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This application claims the benefit under Title 35, U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 61/715,710, filed Oct. 18, 2012 and entitled “DIE ASSEMBLY AND METHOD FOR MANUFACTURING WOUND MOTOR LAMINATED ARTICLE,” the entire disclosure of which is hereby expressly incorporated by reference herein.
BACKGROUND OF THE INVENTION1. Technical Field
The present disclosure relates generally to a progressive stamping die assembly apparatus, and more particularly to an apparatus for the manufacture of a wound stator core made from a continuous strip of material.
2. Description of the Related Art
The manufacture of parts, e.g., stators and rotors for electric motors, ignition assembly cores, or other parts is well known in the art. One known method is to use individual laminas that are blanked from a continuous strip of stock material and are then stacked and bound together to form the completed part. Progressive die assemblies are used for producing such lamina stacks, in which a strip of lamina material is fed through a sequence of punching steps to progressively form the individual laminas to the desired end configurations.
Alternatively, a wound laminated article may be created by winding a continuous strip of material around a spool, in the manner of a spooled tape, such that the substantially cylindrical stator core is created by winding several layers of the continuous strip over one another. These wound laminated articles may be referred to as “axial flux” stators, which have stator slots extending radially outwardly through the stator material rather than axially along the stator walls as is common in stacked configurations. Axial flux stators typically have wire “end turns,” i.e., the wire bend between slots, which begins beyond the axial end of the stator slot in order to avoid impingement of the wire on the sharp corner at the end of the slot.
However, in some cases it may be desirable to form the end turns of the wire such that the wire bends as the wire exits from the stator slot. In traditional axial flux stator cores, this may expose the wire to a sharp corner at the end of the slot.
What is needed is a punch and die assembly and method which is an improvement over the foregoing, e.g., which facilitates the formation of end turns at the axial ends of the stator slots.
SUMMARYThe present disclosure provides a method and apparatus for forming a metal article, such as a stator core, from a continuous strip of wound sheet stock material. The sheet stock material is converted from the sheet stock to a formed material including winding slot cutouts. This strip of formed material is then wound around an arbor into the finished article, such as the stator core, with the plane of the incoming formed strip material remaining substantially parallel with a longitudinal axis of the finished article.
The winding slot cutouts in the formed material are maintained at a substantially constant width throughout most of the radial extent of the resulting winding slots in the finished article, except that one or more of the first and/or last wound layers (i.e., the radially innermost and radially outermost layers) may define winding slot cutouts that are wider than the other winding slot cutouts. Where several radial layers are altered in this way, the cutout widths are progressively expanded such that the resulting winding slot has terminal ends with edges that defining a stair-step profile that approximates a “radiused” or rounded edge. This rounded edge profile protects windings projecting radially into or outwardly from the winding slots near the edge of such slots.
In one form thereof, the present disclosure provides a production machine comprising a punch and die assembly comprising: an upper punch assembly comprising a plurality of punches longitudinally arranged with respect to one another along a first direction; a lower die assembly configured to cooperate with the plurality of punches of the upper punch assembly to punch a plurality of lamina features into a strip of material, the lamina features substantially within the plane of the strip; a material feed path passing between the upper punch assembly and the lower die assembly, such that the plurality of punches are selectively engageable with the material feed path to selectively punch one of the plurality of lamina features into the strip as the strip moves along a material feed path direction; a rewinding apparatus positioned downstream of the punch and die assembly, the rewinding apparatus rotatable to take up material from the material feed path after the lamina features are punched into the strip.
In another form thereof, the present disclosure provides a method of producing a wound article from a strip of material, the method comprising: feeding a strip of bulk material to a punch and die assembly; punching a plurality of winding slot cutouts into the bulk material to create a formed material; and winding the formed material around itself such that a substantially cylindrical structure is created, the plurality of winding slot cutouts selectively aligned with one another to create at least one winding slot in the substantially cylindrical structure, wherein the step of punching a plurality of winding slot cutouts comprises punching a cutout having a first cutout size at intermediate radial layers of the substantially cylindrical structure and a second cutout size for at least one of a radially innermost and radially outermost layers of the substantially cylindrical structure, the second cutout size greater than the first cutout size such that at least one axial end of the winding slot defines a stair-step profile approximating a rounded corner.
In yet another form thereof, the present disclosure provides a stator core comprising: a central opening bounded at its periphery by an innermost layer having at least one innermost winding slot cutout defining an innermost cutout width; an outermost layer radially spaced from the innermost layer and having at least one outermost winding slot cutout defining an outermost cutout width; and a main stator body comprising a plurality of intermediate layers between the innermost layer and the outermost layer, each of the plurality of intermediate layers having at least one intermediate winding slot cutout defining an intermediate cutout width, the innermost layer, the outermost layer and the intermediate layers formed from a continuous strip of wound material such that the innermost winding slot cutout, the outermost winding slot cutout and the intermediate winding slot cutouts are respectively aligned with one another to form a winding slot, and at least one of the innermost cutout width and the outermost cutout width is larger than the intermediate cutout width, whereby the winding slot defines a stair-step profile approximating a rounded edge at a radial end of the winding slot.
The above-mentioned and other features of the disclosure, and the manner of attaining them, will become more apparent and will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate an embodiment of the disclosure and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
DETAILED DESCRIPTIONReferring now to
When used in a motor or generator assembly, for example, bundles of conductive (e.g., copper) windings are received within winding slots 20 and interconnected with one another. When article 10 is assembled with a rotor (not shown), these windings can electrically (i.e., electromagnetically) interact with the rotor to form a motor system capable of converting electrical charge to a motive force. Conversely, the assembly of article 10 and the rotor may be used to form a generator system capable of converting motive force to electrical charge.
Winding wire 28 (
Turning now to
As described in detail below, each successive layer of formed material 126 wound around takeup reel 101 is geometrically sized and configured by punch and die assembly 104 to precisely overlay the preceding layer such that winding slots 20 radially align to extend continuously radially outwardly from innermost layer 12 to outermost layer 14 along radial axis AS (
However, as noted herein, the width of winding slots 20 flares outwardly at the radial terminal ends of winding slots 20, i.e., the ends adjacent to innermost layer 12 and outermost layer 14 (
In addition to formation of such uninterrupted winding slots 20, the process of creating wound article 10 (i.e., stamping bulk material 106 and rewinding the resulting formed material 126, as further described below) may also create weld slots 34 in a surface of article base 18 opposite winding poles 24, as shown in
Winding slot cutouts 150 (
However, it is contemplated that the nature of the alignment of winding slot cutouts 150 can be altered to produce any longitudinal and cross-sectional geometry for winding slots 20, as required or desired for a particular application. Referring to
Similarly,
Turning again to
Production begins with a spool of wound bulk material, shown as material spool 102 in
Bulk material 106 is fed from material spool 102 to intake 108 of production machine 100. Intake 108 may include various apparatuses for preprocessing of the bulk material 106, as required or desired for a particular design and desired end product. For example, a first preprocessing step may be performed at intake 108 by material cleaner 112, which removes particulate matter, grease, or other impurities from one or both sides of bulk material 106. Removal of such impurities may be desirable to maintain fine control over the subsequent punching and rewinding of formed material 126. In addition, intake 108 may include edge guide 114 to monitor and/or adjust the alignment of bulk material 106 with respect to punch and die assembly 104. Edge guide 114 maintains bulk material 106 in a desired spatial arrangement with respect to upper punch assembly 116 and lower die assembly 118 of punch and die assembly 104, even if bulk material 106 is unevenly wound upon material spool 102. Other preprocessing steps and/or apparatuses may be employed as required or desired for a particular application, such as for trimming bulk material 106 to a desired width, creating cuts or perforations at desired locations, printing upon material surfaces, or the like.
Upon exiting a downstream end of intake 108, bulk material 106 enters the upstream end of punch and die assembly 104. As used herein, an “upstream” direction is toward the source of bulk material 106 (e.g., material spool 102), while a “downstream” direction is opposed to the upstream direction and oriented toward the destination of formed material 126 (e.g., takeup reel 101). Production machine 100 generally moves materials 106, 126 in a downstream direction along feed direction DF (
As best illustrated in
Turning now to
Turning back to
One exemplary system and method for transversely moving a die station with respect to other adjacent structures is disclosed in U.S. Pat. No. 6,742,239, filed Oct. 1, 2002 and entitled PROGRESSIVE STAMPING DIE ASSEMBLY HAVING TRANSVERSELY MOVABLE DIE STATION AND METHOD OF MANUFACTURING A STACK OF LAMINAE THEREWITH, the entire disclosure of which is hereby expressly incorporated by reference herein. Particular structures and systems for providing motive force to move upper punch and lower die assemblies 116, 118 may be arranged similarly to the system of U.S. Pat. No. 6,742,239, or may be differently arranged (i.e., hydraulically or pneumatically driven systems, manual slides, and the like).
Turning back to
Turning again to
As best seen in
Turning to
To compensate for slight variations or inconsistencies in the downward travel of takeup reel 101, pressure roll 146 may have a slight give (e.g., provided by an internal spring preload) to maintain such constant pressure upon incoming formed material 126. In addition, auxiliary pressure roll assemblies 148 may be provided along the outer surface of takeup reel 101, as shown in
The motive force for advancing materials 106, 126 may be provided by takeup reel 101, which “pulls” such material along direction DF (
A method of operation of production machine 100 to produce wound laminated article 10 will now be described with respect to punch and die assembly 104 (
As noted above, bulk material 106 is first provided from material spool 102 to punch and die assembly 104 via intake 108. Initially, punch and die assembly 104 is configured such that the widest die insert 120 and the associated widest punch 121 are aligned below and above bulk material 106. This configuration will allow radially innermost layer 12 to have winding slot cutout 150 (
With bulk material 106 so aligned between upper punch and lower die assemblies 116, 118, punch and die assembly 104 is activated by controller 145 to create a first winding slot cutout 150 (
As noted above, bulk material 106 (and the newly finished formed material 126 as shown in
For the next set of twelve winding slot cutouts 150, upper punch and lower die assemblies 116, 118 are indexed along direction DT (
In addition, advancement of formed material 126 must now be along a distance slightly larger than distance DA1 (
In the illustrated embodiment of
Further, this progressive narrowing shown in
In order to maintain the illustrated constant width of winding slot 20 throughout the intermediate layers between the outer and inner “flared” layers, the die insert 120/punch 121 combination having width W1 may be used repeatedly for as many layers as are desired. During this time, with each increase in circumference of article 10 resulting from the addition of another layer of formed material 126 taken up by takeup reel 101, the distance of advancement of material 126 along direction DF is increased accordingly. By the time radially outermost layer 14 is ready for forming at punch and die assembly 104 and takeup by takeup reel 101, advancement distance DA2 (
In addition, the final, outermost five layers wound of formed material 126′ around article 10 may employ ever increasing widths W1, W2, W3, W4, W5 of winding slot cutouts 150, as shown in
The timing and amount of advancement of materials 106, 126, as well as the actuation of punch and die assembly 104 and any structures provided in intake 108 are controlled and monitored by controller 145. Further detail on an exemplary system and method from control over punch presses made in accordance with the present disclosure is presented below, in the context of punch and die assembly 204 (it being understood that punch and die assembly 104 may have similar systems and functions). Controller 145 is programmed to steadily increase the advancement distance from DA1 at the beginning of the winding process to DA2 at the end of the winding process in order to maintain radial continuity of winding slots 20 as described in detail above.
Controller 145 is also programmed to halt the advance of materials 106, 126 by stopping the driven advancement of takeup reel 101 (or other powered roller), in order to actuate punch and die assembly 104 to create winding slot cutout 150, pin hole 138, and/or weld slot notch 142. Edge guide 114 is actuated as necessary by controller 145, or by its own internal controller, to maintain the spatial relationship of bulk material 106 with respect to punch and die assembly 104, as noted above. Controller 145 may further monitor the status and operation of material cleaner 112 to ensure proper operation thereof, together with any other systems which may be chosen for intake 108, material spool 102, or the other systems of production machine 100.
Movement of lower die 118 along direction DT, which is transverse to feed direction DF of bulk and formed materials 106, 126, is one exemplary method of producing stator core 10 as described above and shown in
Referring to
Referring to
Lower assembly 218 also includes three layered components fixed to one another. Die block 256 forms a lower guide and clamping structure for material 106, 126, as noted above, and includes dies 220 of varying sizes into which a correspondingly sized punch body 286 is received to punch cutouts 150 into material 106, 126. Like lower die 118, described above, the plurality of die inserts 220 and punch bodies 286 define varying widths W1, W2, W3, W4, W5 for creation of cutouts 150 having corresponding widths selectively chosen as desired for production of stator core 10.
Channel block 258 of lower die assembly 218 includes chutes 290 formed therein and sized to receive slugs 277 having various widths W1, W2, W3, W4, W5. Slug 277 after being punched from material 106 to form a respective cutout 150, falls downwardly for disposal and evacuation via conveyor 278 as further described below. Guide block 260 forms the bottom layer of lower die assembly 218, and has four alignment guides 233 mounted thereto which are slidingly received on alignment rails 232. Alignment guides 233 cooperate with rails 232 to constrain motion of upper and lower assemblies 216, 218 along direction DP while preventing any significant or appreciable lateral shift and maintaining linear stability.
Referring back to
Referring to
Referring specifically to punch assembly 291 as shown in
Punch head 282 is acted upon by punch springs 284, which bias punch assembly 291 upwardly into a disengaged state so that after press head 280 has impacted punch head 282 to create cutout 150, the lower end of punch body 286 automatically retracts away from engagement with the feed path of material 106. When so disengaged, material 106 may advance along direction DF to initiate the next punch process.
Tray 276 is affixed to guide block 260 and extends beneath all five chutes 290. This arrangement facilitates the easy removal of slugs 277 from punch and die assembly 204 after they have been punched from material 106. Tray 276 is positioned so that it can catch slugs 277 that have fallen through any one of chutes 290. In an exemplary embodiment, tray 276 is configured with conveyor 278, which can transport slugs 277 from guide block 260 to an external location (not shown) for subsequent disposal or recycling. Conveyor 278 may be a standard type commercially available, such as a vibratory- or low-profile belt-type conveyor. One exemplary vibratory-type conveyor useable with punch and die assembly 204 is the Model 250 conveyor manufactured by Vibro Industries, Inc. One exemplary low-profile belt-type conveyor is the 6200 series low-profile belt conveyor manufactured by Dorner® Manufacturing Corp.
The punching process of punch and die assembly 204 is accomplished by actuating press 222 downward through channel 251 while upper assembly 216 and lower assembly 218 remain stationary. As noted above, cylinder 265 pulls actuator rod 266 downward, (optionally compressing dust boot 270), so that press 222 descends and press head 280 engages one of punch assemblies 291-295 to punch out a cutout 150 of predetermined shape from material 106. To change the width and/or size of cutout 150, a different punch assembly 291, 292, 293, 294, 295 and its associated die insert 220 is aligned with press 222 by advancing upper punch and lower die assemblies 116, 118 along direction DP. For example, as described in detail above with respect to punch and die assembly 104, punches 291-295 defining differing widths W1-Ws may be used at the beginning and end stages of producing of wound article 10 (
While the above description describes the structure and operation of punch and die assembly 204 with respect to punch assembly 291, the structure and operation of each of the four other punch assemblies in
In general,
To create the exemplary embodiment of stator core 10 shown in
For this embodiment, as in the previous embodiment, bulk material 106 is advanced by distance DA1 (
Like the previous embodiment, as takeup reel 101 (
When this “switch punch assembly” command is issued, controller 145 activates linear motor 262 to shift driven block 263 (and, therefore, upper punch and lower die assemblies 216, 218) along a desired direction (i.e., along direction DP). The distance of this shift is determined by the distance between the punch assembly 291-295 that was previously aligned with punch press 222 and the punch assembly 291-295 that is desired to be aligned with punch press 222. To measure the movement of upper and lower assemblies 216, 218 as motor 262 moves, encoder 272 is provided. Encoder 272 rides along encoder track 274, providing linear advancement information indicative of the movement and distance traveled of assemblies 216, 218. This linear advancement information is then relayed to controller 145, which in maintains or halts the movement of linear motor 262 to achieve the desired location of assemblies 216, 218. In short, controller 145 can control the linear advancement of both assemblies 216, 218 along direction DP, and of material 106, 126 along direction DF, so that the correct punch assembly is engaged by press 222 for a given stage of the winding process of wound article 10.
For example, as punch and die assembly 204 is stamping slot cutouts 150 for innermost layer 12 during the earliest stage of the linear advancement of materials 106, 126, assemblies 216, 218 are positioned such that press 222 engages punch assembly 295 to use die insert 220 having the widest width W5 (
When radially outermost layer 14 is complete and wound upon article 10, formed material 126′ may be severed and the process may restart by again beginning creation of formed material 126, as illustrated in
While this invention has been described as having an exemplary design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
Claims
1. A stator core comprising:
- a central opening bounded at its periphery by an innermost layer having at least one innermost winding slot cutout defining an innermost cutout width;
- an outermost layer radially spaced from said innermost layer and having at least one outermost winding slot cutout defining an outermost cutout width; and
- a main stator body comprising a plurality of intermediate layers between said innermost layer and said outermost layer, each of said plurality of intermediate layers having at least one intermediate winding slot cutout defining an intermediate cutout width,
- said innermost layer, said outermost layer and said intermediate layers formed from a continuous strip of wound material such that said innermost winding slot cutout, said outermost winding slot cutout and said intermediate winding slot cutouts are respectively aligned with one another to form a winding slot, and
- at least one of said innermost cutout width and said outermost cutout width is larger than said intermediate cutout width, whereby said winding slot defines a stair-step profile approximating a rounded edge at a radial end of said winding slot.
2. The stator core of claim 1, wherein:
- said innermost cutout width is larger than said intermediate cutout width; and
- said outermost cutout width is larger than said intermediate width,
- such that each radial end of said winding slot defines said stair-step profile approximating a rounded edge.
3. The stator core of claim 1, further comprising a plurality of outer layers disposed between said outermost layer and said plurality of intermediate layers, wherein:
- each of said plurality of outer layers respectively defining a plurality of outer cutouts aligned with and forming a portion of said winding slot, and
- said plurality of outer cutouts defining progressively smaller outer cutout sizes as said plurality of outer layers progresses radially inwardly, such that said stair-step profile more closely approximates a rounded edge at the radial outer end of said winding slot.
4. The stator core of claim 3, wherein a width difference between neighboring pairs of said outer cutouts along said winding slot is one of:
- progressively smaller than a corresponding width difference between each other neighboring pair of said outer cutouts;
- progressively larger than a corresponding width difference between each other neighboring pair of said outer cutouts; and
- substantially equal to a corresponding width difference between each other neighboring pair of said outer cutouts.
5. The stator core of claim 1, further comprising a plurality of inner layers disposed between said innermost layer and said plurality of intermediate layers, wherein:
- each of said plurality of inner layers respectively defining a plurality of inner cutouts aligned with and forming a portion of said winding slot, and
- said plurality of inner cutouts defining progressively smaller inner cutout sizes as said plurality of inner layers progresses radially outwardly, such that said stair-step profile more closely approximates a rounded edge at the radial inner end of said winding slot.
6. The stator core of claim 5, wherein a width difference between neighboring pairs of said inner cutouts along said winding slot is one of:
- progressively smaller than a corresponding width difference between each other neighboring pair of said outer cutouts;
- progressively larger than a corresponding width difference between each other neighboring pair of said outer cutouts; and
- substantially equal to a corresponding width difference between each other neighboring pair of said outer cutouts.
7. The stator core of claim 1, wherein said innermost cutout width and said outermost cutout width are both larger than said intermediate cutout width, whereby said winding slot defines a stair-step profile approximating a rounded edge at both an inner and outer radial ends of said winding slot.
8. The stator core of claim 1, wherein said innermost winding slot cutout, said outermost winding slot cutout and said intermediate winding slot cutouts each define a cutout geometry substantially equivalent to one another, whereby sidewalls at respective sides of each said cutout have a corresponding sidewall profile.
9. A production machine comprising:
- a punch and die assembly comprising: an upper punch assembly comprising a plurality of punches longitudinally arranged with respect to one another along a first direction; a lower die assembly configured to cooperate with said plurality of punches of said upper punch assembly to punch a plurality of lamina features into a strip of material, said lamina features substantially within the plane of the strip of material; a material feed path passing between the upper punch assembly and the lower die assembly, such that the plurality of punches are selectively engageable with the material feed path to selectively punch one of the plurality of lamina features into the strip of material as the strip of material moves along a material feed path direction;
- a rewinding apparatus positioned downstream of said punch and die assembly, said rewinding apparatus rotatable to take up material from said material feed path after the lamina features are punched into the strip of material.
10. The production machine of claim 9, wherein said first direction is transverse to said material feed path direction.
11. The production machine of claim 9, wherein said first direction is aligned with said material feed path direction.
12. The production machine of claim 9, wherein each punch of said plurality of punches is sized differently from every other punch in said plurality of punches.
13. The production machine of claim 12, wherein each punch defines a width, each said width differing from every other said width.
14. The production machine of claim 13, wherein a difference between each neighboring pair of widths is one of:
- progressively smaller than a corresponding difference between each other neighboring pair of said widths;
- progressively larger than a corresponding difference between each other neighboring pair of said widths; and
- substantially equal to a corresponding difference between each other neighboring pair of said widths.
15. The production machine of claim 13, wherein each said width is defined by a respective pair of opposing die sides of a plurality of dies, each said pair of opposing die sides defining a cutout profile substantially equivalent to a corresponding cutout profile defined by each other said pair of opposing die sides.
16. A method of producing a wound article from a strip of material, the method comprising:
- feeding a strip of bulk material to a punch and die assembly;
- punching a plurality of winding slot cutouts into the strip of material to create a formed material; and
- winding the formed material around itself such that a substantially cylindrical structure is created, the plurality of winding slot cutouts selectively aligned with one another to create at least one winding slot in the substantially cylindrical structure,
- wherein said step of punching the plurality of winding slot cutouts comprises punching a cutout having a first cutout size at intermediate radial layers of the substantially cylindrical structure and a second cutout size for at least one of a radially innermost and radially outermost layers of the substantially cylindrical structure,
- the second cutout size greater than the first cutout size such that at least one axial end of the winding slot defines a stair-step profile approximating a rounded corner.
17. The method of claim 16, wherein said punch and die assembly comprises a movable punch and die assembly having at least a first die and a second die, and said punching step further comprises:
- aligning the first die with the strip of material;
- punching a first series of winding slot cutouts having the first cutout size defined by said first die;
- moving the movable punch and die assembly such that said second die becomes aligned with the strip of material; and
- punching a second series of winding slot cutouts having the second cutout size defined by the second die.
18. The method of claim 17, wherein:
- said step of feeding the strip of bulk material comprises feeding the strip of material in a first direction; and
- said step of moving of the punch and die assembly comprises moving the punch and die assembly in a second direction transverse to the first direction.
19. The method of claim 17, wherein:
- said step of feeding the strip of material comprises feeding the strip of material in a first direction; and
- said step of moving of the punch and die assembly comprises moving the punch and die assembly in a second direction aligned with the first direction.
20. The method of claim 16, wherein the first cutout size defines a first cutout profile that is substantially equivalent to a corresponding second cutout profile defined by the second cutout size.
Type: Application
Filed: Oct 17, 2013
Publication Date: May 22, 2014
Applicant: L.H. Carbide Corporation (Fort Wayne, IN)
Inventors: Thomas R. Neuenschwander (Fort Wayne, IN), Barry A. Lee (Fort Wayne, IN)
Application Number: 14/056,679
International Classification: H02K 1/16 (20060101); H02K 15/02 (20060101);