Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates generally to apparatus
and method for producing electromagnetic devices and more
particularly to such techniques and apparatus for making
stators ~or dynamoelectric machines.
This i9 a division of copending Canadian Patent
Application Serial number 333,103, filed Au~ust 3, 1979.
In the manufacture of a dynamoelectric machine
stator, a nu~ber of relatively thin stator laminations are
punched or stamped from a strip of ~aterial and stacked together
to form a stator core typically having a centrally disposed
axially extending generally cylindrical bore with a plurality
of axially elongated slots communicating with that bore as
defined by a like plurality of stator teeth separating adjacent
slots. The stator teeth frequently have tips near the stator
bore extending toward one another, forming a gap where the
slot communicates with the bore. Windings are then disposed
in the stator slots by either in-slot widing techniques or by
forming the windings and then axially or radially inserting
those windings into the appropriate core slot.
The size wire which may be used in a stator winding
is limited by the gap between adj~cent pairs of stator teeth,
or stating the same fact in a different manner, for a given
size wire the gap between adjacent stator teeth must be
sufficiently large to admit that size wire. While different
considerations prevail for the different techniques of placing
the windings in the stator core slots, the 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.
Among the several objects of this invention may be
noted the provision of a dynamoelectric machine stator fab-
ricating technique for increasing the wire size and/or
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decreasing the gap between adjacent stator -teeth as compared
to the known fa~ricating techniques; the provision of method
and apparatus for improving dynamoelec-tric machine effi.ciency;
the provision of an improved process for inserting prewound
coils into the slots of stator 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
between adjacent stator teeth.
According to the present invention there is provided
a device for deorming the tips of the teeth of a hollow
cylindrical dynamoelectric machine stator core radially inward
throughout the entire axial extent of the core to provide
enhanced openings for the insertion of windings into the core,
the device having a stator bore support for engaging and
supporting the stator core, a plurality of punches each
disposable in a corresponding stator core slot, and means for
forcing each punch toward a corresponding pair of stator
tooth tips.
~RIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a partial end view of a dynamoelectric
machine stator.core comparing the techniques 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 stator portion wi.th enlarged
gap in position on modified coil inserting e~uipment;
Fig. 4 is a perspective view of a stator and one
device for reducing the previously enlarged gap between
certain adjacent pairs of statox core teeth;
Figs. 5A and 5B are end and partial section views
respectively of a portion of a stator in conjunc-tion with
another device for reducing the gap be-tween certain adjacent
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pairs of stator core teeth; and
Fig. 6 is a block diagram illustrating one method
of stator fabrication according to the present invention.
Corresponding reference characte.rs indicate
corresponding parts throughout the several views of the
drawing.
The exemplifications set out herein illustrate the
invention in one form thereof and such exemplifications are
not to be construed as limiting in any manner the scope of
the invention.
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DESCRIPTION OF THE PREFERRED EMBODIME~I
In Fig. 1 a stator core 11 has slots 13, 15 and 17
into which wind.ings are to ~e placed either by directly
winding in the selected slots or by preformin~ the winding
and axially or radially placin~ that preformed winding in
the slots. Each adjacent pair o~ slots has one side thereof
defined by a stator tooth such as 19 or 21, and adjacent
pairs of such LtatOr teeth have tips 23, 25, 27, 29
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31 and 33, which define therebetween an iron gap through which -the wire
or winding must pass to be placed in the stator core.
A conventional iron gap 1 is depicted between the tips 27
and 29.
For the axial insertion of prewound coils, a stator core is
pkaced on a plurality of generally circularly disposed parallel extending
blades which support 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 prewound coils is illus-
trated, for example, in United States Patent 2,432,267 to Adamson, United
States Patent No. 3,324,536 to Hill, and United States Patent No. 3,402,462
to Walker, et al. A representative pair of such blades 35 and 37 are
illustrated in Fig. 1, and such blades typically have lips 39 and 41 which
overlie the respective stator teeth tips 23 and 25 to protect the winding
from the relatively rough stator core during the insertion process. Thus,
such inserter blades, and particularly the lips 39 and 41, reduce the gap
available for the insertion process from the iron gap 1 down to the blade
gap B, as illustratad~ A larger blade ~ap, of course, facilitates ~he
insertion process and allows windings of a larger wire size to be inserted,
if desired. m e larger blade gap, of course, necessitates a greater irongap, which greater iron gaps may lead in the resultant motor to decreases
in operating efficiency.
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 forming the stator teath tips, as illustratad, by
tips 31 and 33. The iron gap 1 and blade gap B for slot 13, as depictad,
illustrate the conventional approach to this problem, however, an iron
gap, as illustrated for slot 15, nearly the same as the blade gap B
illustrated for slot 17, may be achieved by de~orming the tooth tips to
a new wider iron gap 1 in the manner
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illustrated for slo-t 17. This deforma-tion, as illustratea
for tips 31 and 33, may of course be provided by the stator
lamination punching or stamping die, with no enlarging of
the gap between certain adjacent pairs of teeth occurring
after the stator lamination is formed, however since blanks
for rotor laminations are frequently ormed Erom the central
portion stamped out of the s-tator lamination, such a die con-
figuration may be undesirable, in which event the enlarging
of the gaps between the pairs of teeth may take place after
initial stamping of the stator lamination.
In Fig. 2, a punch 51 has been axially inserted in-
to the stator slot 45, and when forced radially inward to the
position illustrated as 51', functions to deflect the adjacent
stator teeth tips ~7 and 49 toward the stator bore and into
the positions 47' and 49', thereby increasing the iron gap.
In practice, a number of such punches, such as 51, would be
generally circularly disposed, and alignable and axially
insertable into the appropriate stator slots simultaneously.
To enlarge the several slot openings, pairs of wedge shaped
members, such as 53 and 55, are relatively moved to urge the
respective punches in a collapsing or radially inward direc-
tion to sumultaneously form as many tooth tips as de-sired
for the particular winding insertion process. T~edge shaped
member 55 ma~ be affixed to a base 57, which base fixedly
supports a bore support member 59, and which supports the
se~eral 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, being
spring loaded in a radial outward direction. Proper align-
ment of a stator core 63 and the upper and lower frame members57 and 61 allows the simultaneous alignment of a punch and
pair of wedge shaped members in each stator slot and forcing
the frame portions 57 and 61 toward one another, simultan-
eously deforms each pertaining pair of tooth tips. The actual
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bend or deformation given a tooth tip in this process, of
course, depends upon the configuration of punch 43, as well
as the configuration of the adjoining bore support portion
of bore support 59. After formin~ in this manner, the
s-tator core has the tooth confi~uration illustrated in Fig.3.
In Fig. 3, the windings to be inserted are placed
over inserter blades, such as 65, 67 and 69, ~hich are cir-
cularly disposed and parallel extending blades similar to
those 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 noted, however, that
these blades difer from those of the prior art in having a
pair of elongated depressions 71 and 73 for accepting 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 conventional manner.
With windings, such as 87, disposed in the stator
20 slots, stator 89 of Fig. 4 may simply be passed over a cylin-
drical forming tool 91 to deform the stator teeth tips radially
outwardly to return the stator bore to its cylindxical con-
figuration, while reducing the gap between adjacent pairs of
teeth, providing more narrow slot openings than would be
otherwise achievable. Forming tool 91 would, of course, have
the diameter of its main cylindrical portion nearly identical
to the diameter of the finished stator bore and may include
a tapered portion 93 to aid the passage of the stator over the
tool and to cause the reforming of the stator tooth tips to
be somewhat progressive.
The stator bore may be returned to a cylindrical
configuration ~nd the gap between adjacent pairs of teeth
reduced by reforming the previously deformed tips employing
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rollers, such as 117, 119, 121 and 123 in Figs. 5A and 5B.
The rollers engage and rollingly traverse the stator bore
interior to displace the stator tee'th tips, such as 101,
radially outwardly to their final position. The rollers
may be cylindrical and rigidly positioned about a circle so
that kheir outermost surfaces coincide with the completed
stator bore. IE the rollers are fixed ln location, they are
spaced and sized so that a stator may be'placed thereover with
the deformed tips falling between rollers, whereupoll the
stator revolves relative to the rollers to deorm the stator
teeth tips. Alternately, the rollers 117, 119, 121 and 123
may be tapered and movable outwardly generally perpendicular
to their respective axes by cams or the tapered 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 illustratè'd-in'Figs. 5A and 5B.
The stator 89 with its deformed stator tooth ti.ps is placed
over the four tapered rollers 117, 119, 121 and 123, and
thereafter the tapered central roller 133 is ~orced toward
the several opposingly tapered rollers to urge those four
rollers outwardly to reform the stator bore. The four outer
rollers have their axles, such as 125, disposed in elongated
slots, such as 129, at either end of each roller so as to
allow the free radial movement of those four rollers when
urged outwardly and into engagement with the stator bore.
From the foregoing it is'now apparent that a novel
method and apparatus for fabricating dynamoelectric machine
stators has been presented meeting the objects and advantai
geous features set out hereinbefore as well as others. Numer-
ous modifications will readily suggest themselves to those of
ordinary skill in this art. For example, insulative slot
liners 103 and bore wedges 105 may be inser-ted in the stator
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in the conventional manner and numerous techniques may be
employed in deforming and reforming the pertaining stator
tooth tips. Thus, for example in the process depicted in
Fig. 6, the step 107 of deforming these teeth tips may be
incorporated into the step 109 oE stamp.ing the stator lam-
inations, as earlier discussed
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The laminations may be assembled at 111 to form a stator core
by the conventional welding or bolting together of those
laminations or by cleatin~ techniques currently in use in
the stator core fabricating art~ The step o~ inserting stator
windings at 113 may include the insertion of insulating and
bore wedges, and may be a single insertion step of a single
winding, or several insertion steps or different windings,
or may be the contemporaneous insertion of a plurality of
different windings. The present invent~on may also be
~10 advantageously employed with other winding techniques such as
in~slot and hand-placed winding. Two techni~ues, both of
- which deviate the stator tooth tips radially inwardly, have
been disclosed~ however r those tooth tips may be deviated in
other ways or in other directionsl as desired, so as to in-
crease the iron gap therebetween. Two techniques for the
reforming step 115 have been disclosed, however, other approaches
could be employed.
The above-described method and apparatus involving
the concept of enlarging the slot openings ! passing prewound
coils through the enlarged slots and reducing the slot open-
ings are also described and claimed in above-identified
parent application Seri~l number 333,103.
These and other modificatlons may be made by those
having ordinary skill in the art without departing rom the
; spirit of the invention or the scope thereof as illustrated ~ -
by the claims which follow.
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