CA1177870A - Field winding and field assembly for dynamoelectric machine and method - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE One-piece field winding for a dynamoelectric machine which comprises a length of strapping edge wound into at least three laterally spaced coils, each coil having plural convolut-ions and connected to at least one other coil by an integral portion of the strapping. A field assembly incorporating the field winding includes a stator ring supporting at least three laterally spaced pole pieces each being surrounded by a respect-ive coil, with electrically insulating means between adjacent convolutions of each coil.

Description

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The present application is a divisional of application Serial No. 397,548, filed March 3, 1982 (a divislonal of Serial No. 288,612, filed October 13, 1977).
The present inv~ntion relates to dynamoelectric field members such as may be pxoduced by winding, to a field winding and to methods and apparatus for producing field windings and field assemblies.

2. Prior Art It is known in the prior art to wind portions such as individual coils of a field member by the edge winding of strapping. While such edge wound coils have been suggested for use in numerous applications, it has not heretofore been the practice to produce complete field members having plural coils by a continuous winding produced from an uninterruptedly contin-uous length of conductive strapping, portions of which may be edge wound.
Summary of the Invention In the present invention, field members of the type used, for example, in the production of automobile starter motors, are wound from start to finish with an uninterruptedly continuous length of conductive wire or strapping which preferably has an insulating coating. In one embodiment disclosed, the winding comprises interconnected coils, and the apparatus for accom-plishing the winding includes a mandrel having core pieces, on for each coil, the strapping being edge wound successively about each of the core pieces. The portions of the strapping con-necting between adjacent coils are edge bent and each extends from the radially outermost convolution of one coil to the radially innermost con~olution of the next adjacent coil. In a modification, the cores upon which the strapping is wound are detachable from the mandrel and transferable with the strapping to provide pole pieces for a dynamoelectric field member. In both embodiments, the mandrel is constructed so that the strap-ping may be supported in position to be guided upon the core '~

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pieces and the Mandrel moved rotationally abollt an axis perpen-d;cular to its major axis for cansing coils to be formed thereon and rotationally ab~ut its major axis for forming connecting portions between coils.
When using a mandrel having detachable core pieces, removable supports are provided for temporarily holding the core pieces while the winding is being made. After the winding is completed~ the supports are remo~ed, the coil shapes are formed as desired, and the mandrel with the removable core pieces is inserted into a stator housing or ring. The core pieces are then connected to the ring by threaded bolts or the like and the man-drel removed from the ring and the winding and pole pieces are thereby assembled to the ring.
Brief Description of the Drawin~
Figure l is a pcrspective view illustrating a starter motor field winding kno~n in the prior art.
Figure 2 is a perspective view illustrating a starter motor field winding accomplished in accordance with the present in-~en$ion and having eleotrical characteristics comparable to the winding of Figure 1.
Figure 3 is a perspective view illustrating a mandrel upon which the winding of Figure 2 has been formed by edge winding.
Figure 4 is a section view taken diametrically across the stator for an automotive starter motor utilizing the field member illustrated in Figure 2.
Figure S is an e~ploded perspective view illustrating a mandrel with detachable core pieces and apparatus used during the winding of a field winding on the detachable core piecesO
Figure 6 is a section view taken diametrically across the ~0 mandrel and associated parts of Figure 5 after the field winding has been wound.
Figure 7 is a section view taken diametrically across a ~tator for an automotive starter motor and a mandrel of the 1 ll; ~8 ~0 t~-pe shown in Figures 5 and 6 and illustratcs one step in the assembly of the field winding wherein the core pieces are used as the field pole piece~.
Figure 8 is a perspective view illu-~trating in simplified form apparatus for use with a mandrel for winding the field winding of thi~ invention. In Figure 8 the mandrel illustrated i~ the mandrel shown in Figures 5 and 6.
Figure 9 is an illustration of a forming step subsequent to the winding of the coils.
lC Figure lO is a perspective view illustrating steps in the assembly of the coils to the stator housing or ring.
Figure 11 is a perspective view similar to Figure lO and illustrating a further step~
Detailed Descri~tion of the Preferred Embodiments Referring to the drawings, reference numeral lO in ~igure l designates a stato~ winding of the type commonly used in starter motors for automobiles. The conductive wire 11 used to fabri-cate the winding is commonly rererred to as Qtrapping. To simplify this prior art illustration, insulation interleaved with the strapping has been omitted. Such strapping comprises a thin~ generally continuous wire strap having a thickness substantially less than the width of its major ~ides. When such strapping is wound by bending the strapping about an axi~
parallel to the major sides thereof~ the resultant bend or winding is described a~ flat bent~or flat wound. When the strap-ping is wound by bending about an axis perpendicular to the major sides of the strapping, the resultant winding i5 referred to as edge bent or edge wound. The winding of Figure l~ having been accomplished generally by bending the strapping about axes parallel to the major sides of the strapping~ is therefore in the nature Or a flat wound winding.
The winding lO haQ a first terminal 12 and a second terminal 14 which are adapted for connection to a battery or ~, other source (not showll) when ~ounted into the housing or yolcc :.,.
, of an electric motor. The first terminal 12 îs at the end of `'~ a start end or leg 16 Or a first coil 18. Coil 18 i~ flat wound and convoluted outwardly from the innermost convolution thereof , to the outermost convolution thereof~ At the commencement of ;~j, the winding of the coil 18; its start end 16 is first flat bent, , and then edge bentO At the end of the winding the finish end or " leg is rotated or twisted approximately 90 about its central ~,-;, axis to for~ an up~ardly extending twisted termination 20 to .
which is soldered a start end or leg 22 o~ a second coil 24.
;- The leg 22 is edge bent downwardly and by combined edge and flat bends rotated approximately 90 about its o~ axis to commence the second coil 24, which is flat wound outwardly from the inner~
most to the outermost convolution. Its outermost convolution is twisted to form a termination 26 that is bra~ed or soldered at 28 to a termination 30 of a third coil 32. Commencing with a start end or leg 34 which is ben`t downwardly and then both edge and flat bent to accomplish a 90 rotation about its own axis, the third coil 32 is flat wound outwardly from the innermost to the outermost convolution. The outermost convolution i~ both bent and twisted to form the termination 30. The start leg of ; the third coil 32 is soldered or brazed to the start end or leg 36 of a fourth coil 38. The coil 38 is also flat wound and con-voluted outwardly from the innermo~t convolution thereof to the outermost convolution thereof. At the commencement of the wind-ing of the fourth coil 38~ its start end 36 is first flat bent and then edge bent and at the end Or the winding the final con-volution includes an up~ardly extending leg 40 which is twisted approximately 90 about its center axis to form the termination

3 14~
~ As previously indicated~ the winding 10 i-~ representative '~ of prior art. The winding is accomplished by individually '~

winding the coils 18~ 24~ 32 ~ld 3~ using four separ~te winding `!n~achines and then soldering or brazing tho terminal cnds of the coils in the manner illustrated in F~gure 1. Considering current flow through the coils and~assuming a positive potential f applied to the first terminal 12 and ground applied to the second terminal 14, a positive current will flow counterclockwise about the first coil 18~ clockwise a~out the second coil 249 counter-clockwise about the thirù coil 32~ and clockwise about the fourth coil 38 if the observer is located outside the periphery of the winding. It is noteworthy that the section~ of strapping which are used for the winding form four separate coils wherein each coil required at least one and sometimes two 90 twists of the strapping about its o~n axis for completion of the coil, edge bending as well as flat bending of the strapping, and brazed or ;soldered connections were required to interconnect the coils~
;~Figure 2 illustrates a winding 48 which is comparable in I
terms of electrical characteristics to the prior winding of Figure l but which, in accordance with the present invsntion~
has been accomplished with an uninterruptedly continuous length of insulated strapping 11. The winding is accomplished without soldering or brazing and twisting or rotation of the ~trapping about its own axis as is required on numerous occasions to accomplish the prior art winding. A particularly notable feature is that the winding of Figure 2 is an edge wound winding as opposed to the flat wound winding of Figure l, Progressing through the generally circular winding of Figure 2, the winding commences with a start end or terminal 50.
,`From the terminal 50 the strapping proceeds horizontally to a flat bend~ from which the strapping proceeds downwardly along a straight section Or a convolution 52, which is edge wound to form a coil 54. It can be noted that the successive convolutions of the coil 54 proceed axially outwardly as they are wound one adjacent the other. Thus the coil 54 increases in axial ;1 lL7"~

`~ thickness as ~uccessive convolutions are a~ded to thc coil.
Comparing this ~eature to the flat wound coil~ Or Figure 1, it ` should be noted that the coils of Fi~ure l each have a sub-,~ stantially constant axial thicknes~ with respect to an axis ; surrounded by the coil~ but each of the coils of the winding lO
; has an increasing radial thickness as the number of convolutions in each such coil increases.
After winding of the coil 54, the finishing portion of the .:
wire is edge turned to form a starting portion or leg 56 ~hich continues uninterruptedly into the first con~olution 58 of an edge wound coil 60 which is wound axially outwardly by edge wind ing until a final convolution or finishing portion 62 is wound.
After completion of the con~olution 62 7 the strapping i~
continued without interruption along a ~tarting portion by a leg 64 which continues without in~erruption to the commencement of the first convolut'ion 66 of an edge wound coil 68. It will be noted that the leg 64 is bent downwardly so that it does not span over the third coil 68, wher~as the aforementioned leg 56 spans from the first coil 54 over the second coil 60. The coil 68 again increases outwardly in axial thickness as successive ; convolutions thereof are wound.
After winding of the coil 68, its finishing portion continues without interruption along an arm 70 and without interruption to form the radially innermost starting portion or convolution 72 of an edge wound coil 74 where, again, the coil progresses axially outwardly in thickness to the final con-'~ volution thereof which iY edge turned to form a finish portion or ter~inal 76. The resultant winding 48 is characterized by a generally cylindrical shape in which the coils 54, 609 68 and 74 are laterally spaced apart and the start and finish portionctwhich interconnect the coils are disposed at the upper axial extreme of the winding as appears in ~igure 2.
In addition to the use of edge winding as opposed to the flat windillg in ~i~re 1 and the use o~ a cont:in~lous strapping ; in the winding of Figure 2, another notable foature Or the winding of Figure 2 is that all coils are wound outwardly from ; an axially`innermost convolution to an a~ially outermost con~o-lution. ~urther~ the winding of ~igure 2 ls generally circular when viewed from either end thereof and the major surfaces of the strapping are parallel to the longitudinal axis of the wind-ing throughout all of the coils and the cor~ection~ therebetween.
Accordingly~ the entire length of strapping used to form the winding 48 has its major surfaces lying essentially along the periphery of the imaginary cylinder which the coils form. After completion of the winding 48, the flat bent part o~ $he start portion or terminal 50 could be either straightened or cut off.
As an alternative, the winding may be accomplished ~ithout the flat bend in the start portion 50. In either event, the winding 48 can be inserted directly into a stator housing or ring and suitable terminal connections made for electrical connection to the terminals 50 and 76. No solder or brazed connections are required in the winding 48, and all connected coils are inter-connected by edge bent strapping portions having major faceslying substantially in the same imaginary cylinder as the major faces of the coils.
Considering the electrical characteristics of the winding 48 7 one can consider that the starting terminal 50 is connected to a source of positive ~oltage, and that the finishing terminal 76 i5 connected to ground. With such connections~ a positive current as "seen" by an obser~er outside the winding will flow counterclockwise in the coil 54, clockwise in the coil 60, counterclockwise in the coil 68 and clockwise in the coil 74 to ground at $he terminal 76. The electrical result ~ill be basically the same as for the prior art coil illustrated in Figure 1.
Figure 3 illustrates the general manner in w}lich a winding L1';"7~ `

such as described in referellcc to Fig~re 2 can be ~ccomplished on a mandrel~ generally clesignated 80. The mandrel 80 com-prises a generally cylindrical body or arbor having four out-wardly projecting and generally rectangular cores 82, 84, 86 and 88 bounded by respective side walls or shoulders 8Za~ 84a~
86a and 88a. Only the cores 82 and 88 and their side wall5 82a and 88a appear in the drawings.
A piece of strapping 11 is secured at one end thereof~
forming the start end 50 of the winding 48, to one end of the mandrel 80 by means of a clamp 90 secured by a fastener 92, The strapping is so secured to the mandrel 80 that, with a single 90 degree bend~ the strapping can be flat bent to commence the i~ermost convolution 52 of the coil 54 which is wound edgewise about the shoulder 82a to produce counter-~- clockwise wound coil 54. It may be noted that other means, not shown, could ~e provided to grip the start end 50 such tha*
the flat bend would be unnecessary.
~ The strapping which form~ the outermost convolution of the - coil 54 is then turned edgewise, extended circumferentially ~ 20 adjacent the upper shoulder~ not appearing in Figure 3, of the ; mandrel core 84, also not appearing in Figure 3~ edge bent downwardly and then wound edgewise in the clockwise direction about shoulder 84a to produce the coil 60 appearing in Figure 2.
Because of the edgewise turning of the strapping after the winding of the coil 54, it will be noted that the edge of the strapping engaging the shoulder 82a is the opposite edge of the strapping which engages the shoulder of the core piece 84. A
study of Figures 2 and 3 will reveal that the coils wound in a clockwise direction have the same strapping edges confronting and engaging the core pieces and those wound in a counter-clockwise direction have opposite edges confronting and engaging the core piece~.
The strapping is then continued from the coil 60 peripher-;

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ally about the m~ndrel 80, cdge b~nt do~wardly adjacent the left hand side of the core 86, not appcaring in ~igure 3, ~nd then edge wound about such core to accomplish the counter-clockwise winding of the coil 68 which appears ln Figure 2.
The strapping is then continued from the coil 68 and along the upper shoulder 88a, as appears in Figure 3, and edge wound clockwise about the core 88 to accomplish the coil 74 The last convolution of the coil 74 is permitted to extend vertically upwardly as appears in Figure 3 to form the terminal 76 which also appears in Figure 2.
Figure 4 schematically ill~strates a starter motor field assembly using the winding of Figure 3. After release of the clamp 90 illustrated in Figure 3, the winding is pulled outwardly and away from the mandrel 80, returned and formed as needed to a generally circular shape, and inserted into a hollow, cylin-; drical stator housing or ring 94. Four individual pole pieces identified by the reference numeral 96, and each preferably ; surrounded by insulating sleeves 979 are then fastened in a circular array to the stator ring at 90 degree circumferential angles by means of suitable fasteners 98 threaded into the polepieces 96 so that the pole pieces 96 project inwardly of the ring 94. In such assembly, both the axially and circumferentially ;; extending side walls of the pole pieces 96 are confronted by the radially innermost edge surfaces of the strapping but insulated from the strapping by the sleeves 977 Only the axially extending side walls~ designated 9g, are illustrated in the section of Figure 4. As is conventional, these are out~ardly flanged or flared to retain the coils thereon. In the illustra-tion of Figure 4~ there is a substantial spacing between the curved inside surface o~ the ring 94 and the radially outermost surfaces of the coils 54, 60~ 68 and 74. In practice, the radial dimensions of the coils 54~ 60~ 68 and 74 relati~e to *he radial length of the pole pieces 96 is pre~erably such that _, 9 _ t'778~
the flared side walls 99 comprcss the several coLls 54~ Go~ G8 and 74 against the inside surface of the stator ring so that the coils are snugly retained on the ring. Suitable terminal connections, not sho~ because well lulown to those skilled in the art, are then provided for connection of the start and finish portions 50 and 76 appearing in Figure 2 to an electrical source.
The field assembly is thus seen to include a one-piece wind-ing comprising a single length of conductive strapping edge wound int~ the laterally spaced and connected coils 54, 60, 68 and 74, one coil surrounding each of the pole pieces 96. Since the ; strapping forming the coils is coated with insulating material, there is electrically insulating means between ad~acent convo-lutions of e~ach coil. As possible alternatives, insulation - could be formed between the coil convolutions after the ~-inding is completed, or insulating strips could be wound with the strapping. When assembled in the ring 94, the adjacently located coils are connected by edge bent portions of strapping integral with the coils and extending from a finishing, radially outermost portion of one coil to a starting~ radially ~0 innermost portion of the adjacently located coil. As is obvious from an inspection of the drawings 9 the major sides Or the coils and also the connecting strapping portions between them are substantially concentric with the inside surface of the ring g4. The same would be true of the connection bet~een coils 54 and 74 ir either one or both of their adjacent termina-tion legs 50 and 76 are edge bent to produce the connection.
~ igures 5, 6 and 7 illustrate a modification wherein a mandrel, generally designated 300, comprises an assembly of parts including core or pole pieces about which coils are edge wound. Upon completion of the winding~ the core or pole pieces are separated from the assembly along with the winding for inser-tion into a stator yoke wherein the core pieces are fastened to the stator yoke so as to function as stator pole pieces.

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~7~7~) The mandrel 300 can be seen to comprise a generally cylin-drical body or arbor 301 having radially outwardly extending keys 302 along the length thereof. The radially extending surfaces of the keys 302 are identified by the reference characters 304 and 306, respectively. The keys 302 are flanked by recessed, axial-ly extending~ arcuate surfaces 308~ there being four such arcuate surfaces 308, each bounded by a pair of radial surfaces 304 and 306. The keys 302 are designed to slidably receive between them core pieces 310, there being one core or pole piece 310 for each arcuate surface 308 ~ Thus for a winding having four coi~s~ thcre ; are four core pieces 310 as illustrated.
Each core or pole piece 310 comprises a generally rectangu-lar body member 312 having arcuate flanges 314 projecting from each axially extending side wall and having a convexly curved outer surface 316 and a concavely curved inner surface 318. The core pieces 310 are shaped to become the pole pieces for the field assembly as will be described below and may be shaped identically to pole pieces presently in use.
As best shown in Figure 6~ the keys 302 and the arcuate surfaces 308 are so constructed that the flanged portion of the core pieces 310 can be slidable in either axial or radial direct~ons relative to the axis of the arbor 301 to be snugly received thereby. The core pieces 310 can then be assembled in abutting relation with the arcuate surfaces 308, whereupon the core pieces 310 provide the same function as the core pieces 82, 84, 86 and 88 illustrated in Figure 3. Since the pieces 310 will become the pole pieces of the completed field assembly, an insulating sleeve 320 is placed on each of the pieces 310 prior to the winding of coils thereon.
The pieces 310 are clamped to the arbor 301 by means of a pair of sliding clamp members 322 and 324 which may be of identical construction. Each has an end plate designated 326 apertured at 328 to receive a shaft part 330 or 332 projecting :

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rrom the opposite ends o~ the nl~ndrel 300 and rour clamping fingers 334 projecting from the corner~ o~ the end plate 326.
The clamp member~ 322 and 324 are adapted to be extended over ., .
opposite ends of the arbor 301 with cach o~ the clamp fingers 334 centered over one of the key~ 302 and with the axially ex-~ tending side edges of the clamp fingers 33~ overlying the flangeportions 314 of the core pieces 310 and the parts of the insu-lating sleeve 320 lying against the flanged portions 314. As clearly illustrated in Figure 6, each clamping finger 334 spans across adjacent flanges 314 of adjacent core pieces 310 when the parts are assembled. The arbor 301 is substantially the same - length as the pieces 310 and the clamp fingers are slightly less than one-half said length. Accordingly, the end plates 326 of ~ !
;; the clamp me~bers 322 and 324, upon assembly of the rnandrel 300, i^
centrally locate the pieces 310 on the arbor 301. ~en assembled to the a~bor 301, the fingerR 334 of the clamp member 322 are ali~ned with and confront the corresponding fingers of the clamp member 324. This assembly is sho~ in Figure 8. The inside surfaces of the side edges o~ the clamp fingers 334 can engage the core or pole piece flange portions 314 with a suffi-ciently close friction fit that the assembled mandrel 300 will remain assembled unless forcibly disassembled. Alternati~ely~
or in addition, separate means (not shown) could be provided for holding the clamp members 322 and 324 in assembled relation to the arbor 301.
- The assembled mandrel comprising the arbor 301, the core pieces 310~ and the clamp member~ 322 and 324 has essentially the ~ame configuration as the mandrel 80 illustrated in Figure 3. Therefore~ strapping can be edge bent or wound around the ~ide walls or shoulders Or the core pieces 310 to form colls and edge bent to duplicate the connecting portions 5~ 64 and 70 shown in Figure 2. Figure 6 shows the mandrel 300 with com-pleted coils designated 336~ 338, 340 and 342 wound thereon.

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lTith reference to ~igures 6 and 7~ tlle core or pole pieccs 310 have centrally located threaded ape.rtures 344 extending therethrough so that they may be used as the pole pieces of a completed starter motor ~ield assembly 345 shown in ~igure 7.
The ~ield assembly 345 includes a stator housing or ring 346 which has an insulating liner 348 and which also has apertures for receiving screws 350 for attachment of the pole pieces thereto.
~ igures 8-10 illustrate in simplified form the steps followed ln the manufacture of the starter motor field assembly ~: lo 345. The winding of the coils on the rnandrel 300 can be accom-plished as illustrated in Figure 8 wherein the shaft part~ 330 and 332 of the arbor 301 are journalled for rotation in opposed parts of a yoke 352 rotatably driven by a yoke drive assembly 354 about an axis extending centrally through the mandrel 300 per-pendicular to its longitudinal axis. The mandrel 300 may be rotated about its longitudinal axis by a rack 356 mounted on the yoke 352 and driven by a drive cylinder 358 or the like and which engages a pinion 360 mounted on the shaft part 332. One end of the strapping 11 can be clamped to the clamp member 322 and guided ~rom a suitable strapping source (not sho~) by a strap guide member 362. As con~entional in other winding procedures, the strapping is placed under tension at its source. Therefore, ; the coils may be edge bent or wound about the core piece 310 by rotation of the yoke 352 and the .connecting strapping parts :~ between coils edge bent by rotation of the mandrel 300 upon ;: energization Or the cylinder 358 whereupon the rack 356 rotat-.. ably driYes the pinion 360. The yoke 352 is rotated in either clockwise or counterclockwise directions to edge wind the coils in the desired directions about the pieces 310~ Suitable tooling 3o may be provided to assist in edga bending the strapping as : necessary to wind the coils and form the connections between coils.

It will be noted in ~igure 6 that the coils are edge wound around the pole pieces with their radially innermost major .
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surraces lying flat ~gain~t and supported by flat surface por-tions of the clamp fingers 334. Acco:rd;.ngly, the major surface of each convolution thereof is substan-tially perpendicular to radial lines extending centrally t~rough the apertures 344.
~After the winding of the coils in the m~lner described above in connection with Figure 8~ the strapping is severed from its ~ source and -the mandrel 300 is removed from the yoke 352 and the .~ clamp members 322 and 324 then removed from the arbor 301. The ` strapping 11 forming the winding is typically quite stiff so : .
that the completed winding itself will retain the core or pole pieces 310 on the arbor 301. After removal of the clamp members 322 and 324, the arbor 301 carrying the pole pieces 310 with the winding thereon is moved to a coil forming machine which modifies the shape of each of the coils so that they have an arcuate outer periphery concentric with the arbor 301 ~ld are suitably shaped for insertion into the stator ring 346. FGrming machines are conventional in the industry and may includeg as sho~ in Figure -9~ one or more forming dies or press members 364. As apparent from an inspection of Fig~re 9~ advancement of the member 364 toward the longitudinal axis of the arbor 301 will cause the coil 342 to be bent or formed into a circular arc ~or insertion into the stator ring 346. All coils wound on the pieces 310 are either simultaneously or sequentially formed to the desired arc.
The arcuate or circular configuration of all of the coils is clearly shown in Figure 7.
After forming of the colls, the insulating liner 348 is preferably wrapped around the core or pole pi0ces 310. As illustrated în Figure 10, the liner 348 may conveniently comprise an insulating paper or the like sheet having plural apertures 366 which are provided to permit contact between the core or pole pieces 310 and the inside surface of the stator ring 346. The liner 348 is wrapped around the assembled arbor and pole pieces.
After wrapping, its ends can be connected as by a piece of tape ' ., ~7~87(~

(not sho~n). This assembly is then inserted into the stator rin 346 and the screws 350 are then inserted through the apertures in the stator ring and threadedly engaged with the pole piecçs 310 to affix them along with the winding and the insulating liner 348 to the ring 346. At such time the parts have the appearance illustrated in ~igure 7. Thereafter~ the arbor 301 is removed from the assembled field assembly 345 as shown in ~igure 11, ready for reuse in the manufacture of another field assemb~y. As believed apparent, the winding and assembly method illustrated in Figures 8-11 can be accomplished manually with the use of simple tool~, or the entire assembly process could be carried out by automatically operating machines with the potential for sub-stantial savings in the cost of manufacture of the conventional starter motor field assemblies utilizing the separately wound coils illustrated in ~igure 1.
Referring to ~igures 3 and 8~ the winding apparatus shown in ~igure 8 could be used for the winding Or coils on the man-drel 80 which would be used instead Or the mandrel 300. In such event, the coils would be wound and t~e connections between coils formed by repeated rotations of the mandrel 80 about the axis of rotation o~ the yoke 352~ i.e., perpendicular to the longitudi-nal axis o~ the mandrel 80, and about the longitudinal axis of the mandrel S0 in the same manner in which the coils are rormed on the mandrel 300. Arter the coils are wound on the mandrel 80, the coil terminal portion 50 is released from the clamp 90 where-upon the winding can be removed by hand. The coils can then be formed to the desired arcuate configuration and inserted into .
the stator ring 94~ Prior to such insertion o~ the coils~ they would either be wrapped by an insulating sleeve (not shown) which . 30 may be identical to the insulator 348 or such insulating sleeve :: may be positioned within the ring 94. Thereafter the pole pieces 96 with the insulating sleeves ~7 thereon would be inserted in-side the winding located in the ring 94 and moved radially out-! ;,.
. -15-wardly through the coils and then attached to the stator ring by the screws or bolts 98 to form the completed field illustrated in Figure 4, While the present application describes thc manner in which a prior art ~Tinding might be substantially duplicated~ it will occur to those skilled in the art that numerous variations are possible, The particular winding described as illustrative of the present invention has the first wound and third wound coils wound counterclockwise, for example, and the second wound and f~urth wound coils wound clockwise. The winding techniques described in the present application, of course, include techniques for shifting the direction of wind as from clockwise to counter-clockwise or vice versa, i.e., winding one side of the strapping against a core when winding clockwise and the opposite side of the strapping against a core when winding co~terclockwise; and the particular sequence of respectively clockwise and counter-clockwise windings is thus variable to suit the desires of the customer. or course, windlngs having other than four coils -. 20 could be made in accordance with the principles of this inven-tion. Four coils are illustrated since this is the common con-figuration for automotive starter motor field windings. This invention is presently believed most suitable for such windings because of the need for the coils thereof to be formed from strapping.
In addition to a substantial savings in the number of operations required to produce a completed field winding~ it is expected that thi3 invention can be practiced to produce a savings in the length o~ strapping used to form a completed winding. Since strapping i-~ normally made from cnpper which is relatively expensive~ and since field windings are normally mass-produced in very large quantities~ a savings Or even a small length Or strapping for each winding can result in a 7~ 70 ~ savings of many thousands o.f dollars a year. It is also con-`- templated that new coil confi~urationS may be made possible by the practice of this invention and in particular that it may.
be possible to obtain field strength characteristics comparable - to the characteri~tics obtained in the prior art using windings ~hich occupy a s~aller space and, thus, this invention could lead to a reduction in the size and wei.~ht of automotive starter motors.
~` Although the presently preferred embodiments of this invention have been described, it will be understood that within the purview of this invention various changes may be made within the scope of the appended claims.

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Claims (7)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A one-piece field winding for a dynamoelectric machine comprising a length of strapping edge wound into at least three laterally spaced coils, each coil having plural convolutions, and each coil connected to at least one other coil by an integral portion of said strapping, the portions of said strapping interconnecting said coils supporting said coils in a circular array of circumferentially spaced coils, and the portions of said strapping extending integrally between coils connected thereby each extend from a radially outermost convolution of one of the connected coils to a radially innermost convolution of the other of the connected coils.

2. The field winding of claim 1 wherein said strapping comprises a thin wire strap having major sides and having a thickness substantially less than the width of its major sides, and wherein said strapping is edge wound about its edges extending between said major sides.

3. A dynamoelectric field assembly comprising a stator ring supporting at least three laterally spaced pole pieces, a one-piece winding comprising a length of conductive strapping edge wound into a plurality of laterally spaced and connected coils, one coil surrounding each of said pole pieces, each coil having plural convolutions, and electrically insulating means between adjacent convolutions of each coil, said ring supporting said pole pieces in a circular array, said pole pieces projecting inwardly from said ring toward the center of said array, said coils being connected by portions of strapping integral with the connected coils, and said connecting portions extending between the radially innermost portion of one coil to the radially outermost portion of a laterally spaced adjacent coil.

4. A dynamoelectric field assembly comprising a stator ring supporting at least three laterally spaced pole pieces, a one-piece winding comprising a length of conductive strapping edge wound into a plurality of laterally spaced and connected coils, one coil surrounding each of said pole pieces, each coil having plural convolutions, and electrically insulating means between adjacent convolutions of each coil, said ring supporting said pole pieces in a circular array, said pole pieces projecting inwardly from said ring toward the center of said array, said coils being connected by portions of strapping integral with the connected coils, said connecting portions extending between the radially innermost portion of one coil to the radially outermost portion of a laterally spaced adjacent coil, said coils extending axially of said array between first and second extremes and all of said connecting portions between said coils being disposed adjacent one of said extremes.

5. A field assembly of claims 3 or 4 wherein said strapping comprises a thin wire strap having major sides and having a thickness substantially less than the width of its major sides, and wherein said strapping is edge wound about its edges extending between said major sides.

6. A method for manufacturing a field winding from strapping of the type having major faces and edges extending between said major faces comprising:
winding a coil commencing with one end of said strapping, said coil having plural turns surrounding an aperture for receipt of a pole piece, said aperture being defined by the surfaces of one of said edges, and winding a second coil surrounding another aperture for receipt of another pole piece defined by the surfaces of one of said edges, bending said strapping as needed to provide an integral connecting portion between said coils with the connecting portion extending from the last wound turn of the first wound coil and the first wound turn of said second coil.

7. The method of claim 6 wherein a third and fourth coil are wound, each having plural turns surrounding respective apertures for receipt of pole pieces, the aperture of each of said third and fourth coils being defined by edge surfaces of said strapping, said fourth coil terminating in a finish portion, and severing said finish portion from the remaining portion of said strapping.