Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
B~CKGRoU~aD _F TH:E: IMVF.NTION
The pxesent invention relates generally to apparatus and tech-
niques for producing electromagnetic devices and more particularly
to such techniques and app2ratus for making stators for dynamo-
electric machines.
In the manufacture of a dynamoelectric machine stator, a num-
ber of relatively thin stator laminations are punched or stamped
from a strip of m~terial and stacked together to form a stator core
typically having a centrally disposed axially extending generall.y
cylindrical bore with a plurality o~ axially elongated slots com-
munica-ting with ~hat bore as defined by a like plurality of statQr
teeth separating adjacent slots. The stator teeth frequentl~ have
tips near the stator bore extending toward one another, formi.ng a
gap where the slot communicates with the bore. T~indings are then
disposed in the stator slots hy either in-slot winding techniques
or by ~orming the windings and then axi.ally or xadially inserting
those windings into the appropriate core slot.
The size wire which may be used in a stator winding is lim-
ited by the gap between adjacent pairs of stator teeth, or stating
the same ~act in a different manner, for a given size wire the gap
between adjacent stator teeth must be sufficiently large to admit
that si~e wire. While different considerations prevail for the
different techniques of placins the windings in the stator core
slots, th~ slot gap still limits the wire size, or the wire size
limits the slot gap, and this gap cannot be further reduced, or
the wire size increased, according to the known stator fabricating
techniques.
SUMMA.~Y Ul'
Among the several objects o this invent.ion may be noted the
provision of a dynamoelectric machine stator fabricating techni-
que for increasing the wire size and~or decreasing the gap between
adjacent stator teeth as compared to the known fabricating tech-
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niques; -the provis~on of method and apparatus Eor
improving dynamoelectric machine efficiency; the provision
of an improved process Eor inserting prewound coils into
the slots of stat~ cores; and the provision of a method
for making a stator for a dynamoelectric machine which
overcomes the limitation imposed by the dimension of
the gap hetween ad~acent stator teeth.
In general~ a process for inserting prewound
coils into the slots of stator cores, in one form of
the inventi.on, includes enlarging certain of the core
slot openings, passing prewound coils through selected
enlarged slot openings, and reducing the certain slot
openings to provide the wound stator.
In a specific embodiment of the invention there
is provided a method o:E making a stator for a dynamo~
electric machine having a stator core with a centrally
disposed axially extendinq generall~ cylindrical bore,
and with a plurality of axiall~ elongated slots communicatin~
with that bore, and a like plurality of stator teeth
separating adjacent slots, with adjacent tips of the
stator teeth forming a ~ap where the slots co~unicate
with the bore, in one form of the invention, includes
enlarging the gap between at least certain ad~acent pairs
of teeth, placing stator windings in selected slots,
and reducing the gap between the at least certain
adjacent pairs of teeth.
According to another aspect of the present
invention there is provided an apparatus for assembling
coils into the slots of stators and the like, the
apparatus having a stator bore support Eor engaginq and
supporting a stator core with means for forming stator
teeth tips radiall~ inward to conform the teeth to the
mb/ - 2 -
bore support. A pl~rality of qenerally circular disposed
parallel extending ~lades are provided for supporting
coils and a stator sore with means heing movable along
the hlades for forcing coils along the hlades and
into stator core sl~ts. Means is provided for reforminq
stator teeth tips r~dially outward to provide a
cylindrical bore stator.
In a specific embodiment of the invention,
there is provided a~ apparatus for assembling coils in
the slots of stators and the like, the apparatus
including a stator ~ore support for enqaginq and
supportinq a stator core, alonq ~ith punches or other
means for forming stator teeth tips radially inwara to
conform tlle teeth to the bore support. A plurality of
~enerally circularly disPosed parallel extendinq hlades
support the coils and stator core while a stripper or
other member moves alonq the blades for forcing coils
along the blades and into stator core slots. The
stator teeth tips are then reformed radially outward to
provide a cylindrical bore stator by, for example,
a plurality of cylindrical rollers, which simultaneous- -
mb/~,,~i - 2a -
~ ` .
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ly enyage and traverse the stator bore interi~r, displacing the
stator teeth tips radially outwardly to the positions they occupied
prior to forming.
BRIEF DESCRIPTION OF T~E DRAWING
Fig. 1 is a partial end view of a dynamoelectric machine stator
core comparing the techni~ues of the present invention to known
prior art;
Figs. 2A, 2B, 2C and 2D illustrate apparatus for enlarging the
iron gap between certain adjacent pairs of stator core teeth;
Fig. 3 illustrates a s~ator portion with enlarged gap in posi-
tion on modified coil inserting equipment;
Fig. 4 is a perspective view of a stator and one device for
reducing the previously enlarged gap bPtween certain adjacent pairs
of stator core teeth;
Figs. SA and 5B are end and partial section viaws respectively
of a portion of a stator in conjunction with another device for re~
ducing the gap between certain adjacent: pairs of stator core teeth;
and
Fig. 6 is a bloc~ diagram illustrating one method of stator
fabrication according to the present invention.
Corresponding reference characters indicate corresponding parts
throughout the several views of the drawing.
The exempiifications set out herein illustrate the invention
in one form thereof and such exemplifications are not to ba con-
strued as limiting in any manner the scope of the invention.
DESCRIP~ION OF T~E PREFERRED E~BODIMENT
In Fig. 1 a stator core 11 has slots 13 J 15 and 17 into which
windings are to be pl~ced eithex by directly winding in the selected
slots or by preforming the winding and axially or radially placing
that preformed winding in the slots. Each adjacent pair of slots
has one side thereof deined by a stator tooth such as 19 or 21,
and adjacent pairs of such stator teeth have tips 23, 25, 27, 29,
31 and 33~ which define therebetween an ixon gap through which the
wire or winding must pass to be placed in the stator cor~
A conventional iron gap I is depicted between the tips 27
and ~9~
For the axial insertion of prewouna coils, a stator core is
placed on a plurality of genera7ly circularly disposed parallel ex-
tending blades which 5upport coils as well as that stator core, and
a stripper or other device moves along the blades, moving the coils
therealong and into stator core slots. Such axial insertion of pre-
wound coils i5 illustrated, for example, in Uni~ed States Patent
2,432,267 to Adamson, United States Patent No 3,324,536 to ~Iill, and
United States Patent No. 3,402,462 to Walker, et al. A representa-
tive pair of such blad~s 35 and 37 are illustrated in Fig. 1, and
such blades typically have lips 39 and 41 which overlie the respec-
tive stator teeth tips 23 and 25 to protect the winding from the
relatively rough stator core during the insertion processO Thus,
such inserter blades, and particularly the lips 39 and 41, reduce
the gap available for the insertion process rom the iron gap I
down to the blade gap B, as illustrated. A larger blade gap~ of
course, ~acilitates the insertion process and allows w.indings of a
larger wire size to be inserted, if desired. The larger blade gap,
of course, necessitates a greater iron gap r which greater iron
gaps may lead in the resultant motor to decreases in operating
eficiency.
Greater blade gap without a concomitant increase in iron gap
and/or a decreased iron gap without a concomitant decrease in blade
gap may be achieved by orming ~he stator teeth tips r a~ illustra-
ted, by tips 31 and 330 The iron gap I and blade gap B for slot
13, as depicted, illustxate the conventional approach to this prob-
lem, however, an iro~ gap, as i~lustrated for slot 15, nearly the
s~me as the blade gap B illustrated for slot 17/ may be achieved
by deformincJ the tooth tip9 to a new wider iron gap I in the manner
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illustrated for 510t 17. This deformation, as illustrated for tips
31 and 33/ may of course be provided by the stator lamination punch-
ing or stamping die, with no enlarging of the gap between certain
adjacent pa.irs of teeth occurring after the stator lamination is
formed, however since blanks for rotor laminations are frequently
formed from the central portion stalnped out of the stator lamina
tion, such a die configuration may be undesirable r in which event
the enlarging of the gaps between the pairs of ~eeth may ~ake place
after initial stamping of the s-tator laminations.
In Fig. 2, a punch 51 has been axially inserted into the stator
slot 45, and when forced radially inward to the position illustra-ted
as 51', functions to deflect the adjacent stator teeth tips 47 and
49 toward the stator bore and into the positions 47' and 49', there-
by increasing the iron gap. In practice, a number of such punches,
such as 51, would be generally circularly disposed, and alignable
and ax.ially insertable into the appropriate stator slots simultane-
ously. To enlarge the several slot ope'nings, pairs of wedge shaped
members, such as 53 and 55, are relativel,y moved to urge the respec-
ti~e punches in a collapsing or radially inward direction to simul~
taneously fQrm as man~ tooth tips as desirea for the particular
winding .insertion process. Wedge shaped member 55 may be affixed
to a base 57, which base fixedly supports a bore support member
5~, and which supports the several punches, such as 51, in a movable
manner. A second frame member 61 may movably support the several
wedges, such as 53, with wedges 53 and punches 51, for example,
bei~g spring loaded in a radial c>utwaxd dixection. Proper align~
ment of a stator core 63 and the upper and lower frame members 57
and 61 allows the simultaneous alignment of a punch ancl pair of
wedge shaped members in each stator slot and forcing the frame po.r
tions 57 and 61 toward one another, si.multaneously deforms each
pertaining pair of tooth -tips. The actual bend or defvrmation given
a tooth tip in this process, o~ cvurse/ depends upon the configura~
-5-
tion of punch 43, as well as the configuration of the adjoining
bore support portion of bore suppor~ 59. After forming in ~his
manner, the stator core has the tooth configllration illustrated
in Fig. 3.
In Fig. 3, the windings to be inserted are placed over inser-
ter blades, such as 65, 67 and 6g, which are circularly disposed
and parallel extendin~ blades similar to ~hose disclosed in the
aforementioned United States Patents Nos. 3,324,536 and 3,402,462
with insertion occurring in the manner disclosed therein. It will
be notedr however, that these blades differ from those of the prior
art in having a pair of elongated depressions 71 and 73 for accep-
ting the respective formed stator teeth tips 75 and 77, as well
as a pair of ribs 79 and 81 outside the depressions 71 and 73 for
spanning the corresponding tooth 83. A stripper 85 is then passed
through the stator bore to axially insert the windings in a con-
ventional manner.
With windings, such as 87, disposed in the stator slots,
stator 89 of Fig. 4 may simply be passed over a cylindrical ~orm-
ing tool 91 to deform the stator teeth tips radially outwardly to
return the stator bore to its cylindrical configuration, while
reducing th~ gap be~ween adjacent pairs of teeth, providing more
narrow slot openings than would be otherwise achievable. Forming
tool 91 would, of course, have the diameter o its maln cylindrical
por~ion nearly identical to the diameter of the finished stator
bsre and may include a tapered portion 93 to aid the passage of
the stator c~er the tool and to cause the reforming of the stator
tooth tips to be somewhat progressive.
The stator bore may he returned to a cylindrical confi~uration
and the gap between adjacent pairs of teeth reduced by reforming
the previously de~ormed tips employing rollers, such as 117, 11~,
121 and 123 in Figs. 5A and 5B. The rollers engage and rollingly
traverse the stator ~ore interior to displace the stator teeth tips,
5~6
5uch as 101, radially outwar~ly to their final position. The rol-
lers may be cylinclrical and rigidly positioned about a circle so
that their outermost surfaces coincide with the completed stator
bore. If ~he rollers are ixed in location, they are spaced and
sized so that a stator may be placed thereover with the deformed
tips falling between rollers, whereupon the stator revolves relative
to the rollers to deform the stator teeth tips. Alternately, the
rollers 117, 119, 121 and 123 may be tapered and movable outwardly
generall~ perpenclicular to their respective axes by cams or the ta-
pered roller 133 or otherwise to create a progressive reforming of
the stator teeth tips, as desired.
The reforming of the stator teeth is rather easily achieved
by the apparatus illustrated in Figs. 5A and 5B. The stator 89
with its deformed stator tooth tips is placed over the our tapered
rollers 117, 119, 121 and 123, and thereafter the tapered central
roller 133 is forced toward the several opposingly tapered rollers
to urge those four rollers outwardly to reform the stator bore.
The ~our outer rollers haYe their axlesl such as 125, disposed in
elongated slots, such as 129 r at either end of each roller so as to
allow the free radial movement of those four rollers when urged out-
wardly ~nd into engagement with the stator bvre.
From the foregoing it is now appar~nt that a novel method and
apparatus for fabricating dynamoelectric machine stators has been
presented meetin~ the objects and advantageous features set out
hereinbe~ore as well as others. Numerolls modifications will readily
sugges~ themselves to those of ordinary skill in this art. For ex-
ample, insulative slot liners 103 and bore wedges 105 may be inser-
ted in the stator in the conventional manner and numerous techniques
may be employed in deforming and reforming the pertaining stator
tooth tips. Thus, or example in the process depicted in Fig. 6,
the step 107 of deforming these teeth tips may be incorporated into
the step 109 of stamping the stator laminations, as earlier discussed.
" ', : .
The laminations may be assemblecl at 111 to form a stator core by
tlle conventional welding or bolting together of those laminations
or by clea-tin~ techniques currently in use in the stator core fab-
ricating art. ~he step o~ inserting stator windings at 113 may
include ~he insertion of insulating and bore wedges, and may be a
single in~ertion step of a single winding, or several inslertion
steps of different windings, or may even be the con~emporaneous
insertion of a plurality of different windings. The present in-
vention may also be advantageously employed with other winding
techniques such as in-slot and hand-placed winding. Two techniques,
both of which deviate the stator tooth tips radially inwardly, have
been disclosed, however, those tooth tips may be deviated in other
ways or in other directions, as desired, so as to increase the iron
gap therebetween. TWQ techniques for the reforming step 115 have
been disclosed, however, other approaches could be employed. These
and other modifications may be made by those having ordinary skill
in the art without departing from the s,pirit of the invention or
the ~cope thereof as illustrated by the~ claims which ~ollow.
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