Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
The present invention relates generally to apparatus
and methods for aligning and placing insulators, such as wedges,
along slots of a magnetic core of a dynamoelectric machine.
Different types of dynamoelectric machines utilize in-
sulating material of suitable dielectric strength for in-
suring that two or more different parts of such machine
remain electrically insulated from one another.
For example, in many constructions, ground or cell
insulation is frequently provided along the walls of slots
in magnetic core members, and windings of a first phase are
disposed along the insulated slots. In those instances
where winding turn portions of a second phase are to share
slots with turn portions of the first phase, it often is
desirable to provide a layer of insulation between the turn
portions of the different phases. For example, in the case
of some electric motor stators with portions of a first wind-
ing phase located along the bottom or closed end of a number
of different slots and with portions of a different winding
phase located along the top or open end of some of the same
slots, insulative "separators" or slot separator wedges ex-
tend axially along the shared slots and separate the wire
Regments of the different phases; whereas slot closing wedges
are disposed at the open end of the slots.
Needham et al U.S. patent 3,038,093 which issued June
5, 1962 shows, in Figure 3 thereof, details of different
parts of an electric motor such as, e.g., slot liners (or slot
"cells"); separators (or slot separator wedges); and pegs
(or slot closing wedges). Other patents that show stator
assemblies and insulators that are incorporated therein are
Phillips U. S. patent 2,998,540 of August 29, 1961; Balke
U. S. patent 2,778,964 of January 22, 1957; and Walker U. S.
patent 3,519,862 of July 7, 1970.
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Equipment has been available long heretofore which has
been used to reliably place slot separator wedges in selected
slots of a magnetic stator core concurrently with the placement
of side turn portions of a winding in the bottoms of the
slots; or to place slot closing wedges along the slots while
winding turn portions are placed therein. Equipment of the
general type just mentioned (as well as processes related
thereto) are described, for example, in Arnold et al U.S.
patent 3,579,818 of May 25, 1971; Smith et al U. S. patent
3,831,255 of June 25, 1973; Hill U.S. patent 3,324,536 of
June 13, 1967; Walker et al U. S. patent 3,694,887 of October
3, 1972; and Moor U. S. patent 3,872,568 of March 25, 1975.
The equipment described in the just mentioned patents may be
used, as desired, to push slot separator or slot closing wedges
vertically upwardly or downwardly, horizontally, or at any
desired angle of inclination or declination along magnetic
core slots. As will be appreciated from a review of the
just mentioned patents, wedges are loaded into a magazine
having a number of slots aligned with a stator holding or
locating station; and the wedges ultimately are pushed by
elongate pushers into and along preselected ones of the
core slots usually cocurrently with the placement of
winding turns therealong.
Although the equipment just discussed has been widely
used in the motor industry, other types of equipment and
processes have also been used whereby windings are made and
placed in core slots without reference to wedges (either of
the slot separator or slot closing type), and wedges must
subsequently be placed in the core slots after winding turn
positions have already been accommodated therein.
For example, winding coils may be developed on a simple
lathe-type of machine and then machine-placed or hand-placed
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in core slots. Alternatively, coils per se may be
developed and then placed in core slots with processes and
equipment of the type described in Mason U. S. patent No.
2,934,099 of April 26, 1960; or Arnold U. S. patent No.
3,797,105 of March 19, 1974. It will be understood that in
these cases it is then usually necessary to effect wedge
placement after placement or some or all of the winding
turns.
One type of equipment that has been used theretofore
for effecting subsequent wedgeplacement has, in effect,
been generally similar to that shown in the above referenced
Arnold U. S. patent 3,579,818 dated May 25, 1971 or Hill
U. S. patents 3,324,536 dated June 13, 1967, and U.S.
3,694,889 dated October 3, 1972. However, when wedges only
are to be placed; it is common practice to eliminate those
portions of the previously known equipment that are provided
in order to handle winding turns; and to use an end turn
blocking or shaping mechanism that will establish or main-
tain a desired clearance between previously placed winding
end turns and paths along which wedges are to be moved
into slots of a core. Prior equipment and methods per- -
taining to subsequent wedge placing and with which we are
familiar are characterized by short comings in that wedges
(and particularly slot separator wed~es) frequently can be
misplaced or improperly positioned wit~n one or more of
the core slots. When this condition occurs, it is necessary
to manually reposition the misoriented slot separator wedges
or, in extremely aggravated cases, manually remove mis-
oriented slot separator wedges and then manually place a new
slot separator wedge along such slots.
It is our belief and understanding that unacceptable
amounts of misorientation of slot separator wedges during :
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placement along previously placed windings is caused partly
by the fact that the wedges will tend to follow the pre-
viously placed wire segments. Thus, such segments have,
in effect, led the separator wedges into a misoriented position.
This problem is aggravated, it is believed, by the fact
that slot wedges are made of a relatively slippery material
(e.g., polyethylene terephalate, one commercially available
A form of whichis sold under the ~mQ MYLAR by E. I. DUPont
DeNemours and Company). The slot liners also are often
formed of this same (or an equivalent) material and the
separator wedges therefore tend to readily slide into
any position directed by the winding turn segments.
Peters U. S. patent 3,805,357 of April 23, 1974 ill-
ustrates one approach that may be followed when attempt-
ing to overcome the misorientation problem just described.
The approach of Peters, however, would require equipment
substantially more complex than the wedge placing mechanisms
used heretofore. Moreover, it is most desirable that wedge
placer methods and equipment be both simple and readily
usable with cores (and thus wedges) of many different axial
lengths. -
It should now be understood that it would be desirable
to provide new and improved methods and apparatus whereby
the above described and other problems may be readily
overcome.
Accordingly, it is a general object of the present
invention to provide new and improved methods and apparatus
whereby slot separator wedges of a predetermined length may
be placed in slots alongside previously placed winding
turn segments in such a fashion that a desired predetermined
orientation of the wedges relative to the segments and slot
walls will be reliably established and maintained.
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It is a more specific object of the present invention
to provide new and improved methods and apparatus whereby
wedges are moved along predetermined core slots having
previously placed wire segments therein, with the wedges
being maintained away from the wires segments; and there-
after causing the wedges to move generally radially along
such slots and into proximity with the wire segments.
It is another specific object of the present invention
to provide new and improved apparatus and methods whereby
wedges are moved axially along a slot and held in a slightly
resiliently deformed condition; and thereafter released to
assume a less deformed configuration adjacent to wire segments
that have been placed in such slot prior to placement of
the wedge.
Another object of the pressent invention is to
provide new and improved methods and apparatus for placing
slot separator wedges, with such apparatus and methods being
relatively simple in nature but most relaib~e in operation.
Yet another object of the present invention is to
provide new and improved apparatus and methods whereby
separator wedges are pushed from one end thereof along guide
means along core slots.
Although the present invention will be readily under-
stood by persons skilled in the art after the following
summary are detailed description are reviewed; persons less
familiar with the art may find it desirable to review the
above referenced patents for a better understanding of the
background of the invention. Of particular interest to
features claimed by us are those pQrtiOnS of the above cited
U. S. patents 3,579,818; 3,324,536; 3,831,255; 694,887; and
3,872,568; that relate to wedge making and wedge placing
mechanisms, and the Peters U.S. patent 3,805,357 dated
106~683
April 23, 1974.
In carrying out the above and other objects of the
present invention, we provide new and improved methods, a
first one of which includes (in one preferred form thereof)
supporting a slotted magnetic core and at least some previously
placed winding turns in a desired position adjacent to wedge
placing apparatus. The previously placed winding turns
generally are located along the bottom or closed end of
preselected ones of the core slots. Separator wedges are
aligned with one end of the preselected magnetic core slots
and axially advanced through the core slots by pushing the
trailing end of the wedges. While the wedges are being
advanced, the leading ends thereof are guided along the core
slots away from the previously placed wire segments, and the
wedges are restrained from engaging and following paths
established by the wire segments, Preferably, at least some
pressure is applied to the wedge in a direction to urge the
wedge toward the open end of the slot and thus away from the
wire segments in the slots. After the desired axial movement
of the wedges along the core slots has been carried out, the
somewhat deformed wedges are permitted to resiliently change
their configuration and assume a position adjacent to the
previously placed wire segments. Thus, at least one form of
our invention contemplates the application of a generally
axially directed force at only the trailing end of a wedge
to cause axial movement of the wedge into and along a core
slot. Concurrently with the application of the axially
directed insertion force; at least the landing end of the
wedge is urged by guide means generally away from wire seg-
ments in the bottom of the slot, and yet the slot walls
(or another guide member) interact with at least the leading
end of the wedge to retain the wedge within the slot during
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axial movement of the wedge.
In a preferred form of apparatus illustrated herein,
and which embodies the invention in one form thereof, we
have illustrated a wedge inserting apparatus that includes
a novel guide tube along which a stator core is positioned.
The guide tube is attached to the base of a conventional
and prior art type of wedge making, storage, and inserting
mechanism. A novel guide ring of our design is carried by
the mechanism base, the guide ring being arranged to hold
first or proximal ends of a plurality of wedge guiding means
that have been illustrated in the form of a number of spring
guide wires. Distal or second ends of the guide wires are
free, but initially located along alignment means (such as
grooves or notches) formed in the guide tube. When a slotted
stator core is positioned over the guide tube, slots of the
core are aligned with tracks of a previously known wedge
magazine along which previously known wedges and wedge pushers
are movable. The guide wires are located so as to extend
in an axial and radial direction from a location within the
bore of a stator at one end thereof to a location radially
outwardly of the bore of the stator at the other end thereof.
As wedges are moved generally axially into and along the
core slots, the leading ends of the wedges enter the slots
and slide along the guide wires while the guide wires urges
the wedges away from wire segments previously placed in the
core slots. After the wedges have been axially inserted along
the slots; the then existing stator assembly is removed from
the apparatus. Upon separation of the wedges and guide
wires, the wedges (which are held resiliently deformed
by the guides) spring back to their original shape and
move radially toward wire segments in the core slots.
The subject matter which we regard as our invention is
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particularly pointed out and distinctly claimed in the
concluding portion of this specification. Our invention
itself, however, both as to its organization and mode of
operation, together with further objects and advantages
thereof, may best be understood by reference to the following
description taken in connection with the accompanying drawings.
FIG. 1 is an elevational view, with parts removed, parts
in section, and parts broken away, of a magnetic stator core
having ground insulation and winding turn segments carried
by a preselected slot thereof;
FIG. 2 is a cross sectional view (with parts broken
away) of the structure shown in Fig. 1, assuming that
Fig. 1 was shown in full, and wherein a slot separator wedge
has been added in the preselected slot in desired orientation
relative to the previosuly placed wire segments;
FIG. 3 is a view substnatially the same as Fig. 2
except that Fig. 3 shows the slot separator wedge in an
orientation that might occur if the wedge followed the path
of a winding turn during wedge placement within the slot;
FIG. 4 is a view substantially similar to Fig. 2 but
which illustrates the slot separator wedge being guided
along the slot during placement of the wedge (or held in
place by a guide wire just after wedge placement);
FIG. 5 is a view taken generally along the lines 5-5
in Fig. 4, and this view further illustrates guiding means,
in the form of a spring steel guide wire, that is utilized
to urge the wedge toward the bore of the core;
FIG. 6 is a view in elevation, with parts broken away
and parts removed, of apparatus embodying the invention
in one form and that may be utilized to carry out our in-
vention in a preferred form thereof; and
FIG. 7 is an exploded perspective view of novel parts
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of the apparatus shown in Fig. 6, which parts would be added
by us to previously known wedge inserting mechanisms in order
to illustrate the presently preferred mode of carrying out
our invention.
Referring now to Figs. 1-5 of the drawings, it will be
appreciated that we have illustrated parts of a stator
assembly 10 that includes, inter alia, a slotted magnetic
core 11 which may be made up of a plurality of magnetizable
laminations; slot linears 12 carried by the core; and wire
segments 14 that in reality are part of a winding carried
by the core slots. Only fragments of the stator assembly
10 have been illustrated in order to simplify the ill-
ustration and description thereof, but it will be under-
stood by persons skilled in the art that the stator core 11
is a generally doughnut-in-shape structure having a first
end face 16, a second end face 17, and a plurality of slots
18 extending between the first and second faces 16, 17.
Slot liners 12 may be formed of any suitable material
(such as electrically insulating paper or, more preferably,
polyethylene terephalate). Alternatively, a suitable in-
sulative coating of a material such as an epoxy resin may
be used in lieu of the slot liners. Fig. 5 reveals parts
of a "phase" or "window" insulator 19. This insulation
may be substantially as shown and described in McNeal U.S.
patent 3,748,510 which issued on July 24, 1973. Alter-
natively, the phase insulation 19 may be small, unconnected
segments of insulation that are ultimately trapped bétween
adjacent end turns of different winding phases.
Although a complete stator assembly has not been
illustrated in the appended drawings (other than the phantom
showing in Fig. 6); the details of entire stator assemblies
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are well known by persons skilled in the art. This know-
ledge is evidence, for example, in the above referenced
Needham et al U. S. patent.
~eferring now once again to Fig. 1, it is to be
understood that the wire segments 14 are disposed
(ultimately, along with other wire segments) in a number of
preselected slots 18. After the wound coil or coils that
include segments 14 have been disposed in the core slots, it
is desirable to place a separator or "separator wedge" (as
illustrated for example at 21 in Fig. 2) along the wire
segments 14 that are in a slot that is to ultimately
accommodate portions of another winding. It is to be
understood that "different winding phases" means dif-
erent winding sections, whether they be for different phases
in a typical poly-phase motor; or whether they be main and
capacitor winding phases, or main, extended main, or starting
phases in split-phase motors.
When prior equipment has been utilized for placing
wedges 21, it has become apparent that the wedges 21 may
(if permitted to follow along wire segments 14 during place-
ment thereof) track along a wire segment and ultimately
become drastically misoriented. This is represented, for
example, by the orientation of wedge 21 in slot 18 as shown
in Fig. 3 after it would have tracked the wire segment 15.
The objectionable condition depicted in Fig. 3 may be
avoided by utilizing a process wherein a wedge (or wedges)
is restrained from contacting the wire segments 14 until
after the wedge is finally positioned axially within a slot
18. With refernce to Figs. 4 and 5, one method by which we
can achieve this desirable objective will now be described.
With specific reference to Fig. 4 it will be observed
that the wedge 21 has been illustrated in a resiliently
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deformed or bowed condition. This is because the wedge is
constrained to remain toward the slot opening 22 by an
elongate guide means (that has been illustrated as a segment
of a spring steel guide wire 23). During the time that the
wedge 21 is being moved axially along the slot 18, the
guide wire 23 will hold the wedge 21 away from the wire
segments 14; and the legs 24, 26 of the wedge therefore
cannot become enmeshed with and guided by any of the wire
segments 14. The relationship between the wedge 21,
guide wire 23, and wire segments 14 within the slot 18 (both
during and at the end of a wedge insertion step) is clearly
revealed in Fig. 5.
After the wedge 21 has been postioned as desired axially
along the slots so that the leading and trailing ends 27,
2~, of the wedge are postioned as desired axially relative
to the end faces 16, 17 of the core; the core assembly
(including one or more wedges 21) and guide wires are
moved axially relative to one another so that the wedges
are free to resiliently spring or snap toward the bottoms
of the slots and assume the relative position therein de-
picted by Fig. 2.
Figs. 6 and 7 have been provided primarily to ill-
ustrate one form of apparatus that may be utilized during
the practice of the invention described hereinabove.
More specifically, Fig. 6 illustrates different parts
of a machine or apparatus 30, some parts of which have been
in use long prior to the present invention. The apparatus
30 includes a wedge guide cage 31, a wedge guide housing 32,
and a plurality of expandable blades 33 which move radially
relative to the cage 31 for the purpose of establishing an
unobstructed path for wedges as they are pushed from the
housing 32 toward a stator core. The blades 33 are biased to
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an innermost position by a garter-like spring 34 and other
not shown springs. These blades are urged radially out-
wardly by the action of an axially movable cam 36. A
plurality of wedge pushers (a portion of one of which is
illustrated in phantom at 35) are movable along axially
extending paths established by the housing 32 and by
radially extended pairs of blades 33. The parts of apparatus
30 specifically described in this paragraph are old in the
art and have been utilized prior to our invention.
It will be understood that a wedge maker and wedge
magazine of any conventional type are positioned beneath the
base 36 of the housing 32. Thus, wedges are made by the not
shown wedge maker and placed in the not shown magazine.
Then, at appropriate times, the leading ends of a number of
wedge pushers 35 will move upwardly along the apparatus 30
to advance wedges from the wedge magazine, along the housing
32, and ultimately along prselected slots of the stator
assembly 10.
Although the movable blades 33 have been used prior
to the present invention, it is now noted (primarily for
background purposes) that the movable blades 33 are effective
to insure that end turns 37, 38 of the windings of the
stator assembly 10 are moved or held radially outwardly
from the path taken by wedges 21 as they are being inserted
axially into the slots of a stator. Wedge makers, wedge
pushers, and wedge magazines usable with or as part of the
apparatus 30 are shown and described in detail in the prior
art refernced hereinabove. Accordingly, additional details
concerning such components are not included herein except
by reference to such prior art.
With continued reference to Fig. 6, it will be observed
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that we have provided an adapter 41, a cage or guide tube
42, an alignment key 43, a plurality of guide wires 23, and
means in the form of a bolt 44 for fastening the guide tube
and adaptor together.
The adaptor 41 is shown fastened to the cage 31 by
means of four bolts 46; and the guide tube 42 is aligned
so that holes therein will meet with dowel pins 47 which
seat in the adaptor 41. The bolt 44 of course fastens the
guide tube 42 to the adaptor 41. A novel guide wire
retaining ring 48 is provided with at least two set screw
receiving apertures 49 by means of which the ring 48 is
clamped to the wedge guide housing 32. The holder ring is
provided with a plurality of intersecting hole pairs, one
of which accommodates a guide wire 23 and the second of
which accommodates a set screw that is utilized to clamp
a guide wire 23 end in the ring 48.
In Fig. 7, we have illustrated the guide tube 42;
key 43; guide wires 23; holder ring 48; one of the set screws
51 that are received in the tapped holes 49 of the holder
ring; and one of the set screws 52 which is accommodated in
the openings 53 of ring 48 for locking in place guide wires
23 that have been positioned in preselected ones of the
apertures 54 in ring 48. Screws 46 are, of course, accom-
modated by holes 56 in the adaptor 41.
In the fabrication of the parts illustrated in Fig.
7, we deem it to be preferably to machine the guide tube
42 from a substantially solid piece of material. We
machine the free or distal end 56 thereof to provide a
tapered configuration so that a stator core may be easily
centered with respect thereto and then slid therealong. The
body of the guide tube 42 is provided with a number of milled
slots 57 to form a cage-like structure along which the free
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1069~33
or distal ends of the guide wires 23 may be diposed as
best revealed in Fig. 6. The tube 42 has yet another slot
milled therein in which the key 46 may be press fit or soft
soldered. The key 46 then interfits with a stator slot
opening and ensures that the stator slots will be properly
aligned with the guide wires 23 and wedge guide housing
paths.
In one actual reduction to practice of the invention,
the guide wires 23 were made from pre-straightened music
wire having a diameter of .060 of an inch. Music wire
was utilized because it is a commonly available, relatively
low cost form of spring steel. However, substantially any
other type of material could be used provided that it had
suitable spring and strength characteristics for the in-
tended application. The springy characteristic of the guide
wires is useful because the guide wires are relied upon to
hold the wedges 21 away from wire segments 14 that have
been previosuly positioned in a core slot 18 as discussed
hereinabove. Similarly, the material selected for use as
the guide wires 23 should be sufficiently strong to prevent
such wires from yieldably bending as they are stressed to
dotted line positions thereof as illustrated for example
by the phantom line position of wire 23 in Fig. 6.
It is noted that even though round guide wires have
been illustrated, the shape thereof is not believed critical
to successfully practicing the invention; and rectangular,
flat, or other shaped of elongate flexibe wedge guides
clearly could be used. As wedges 21 are pushed in a
generally axial direction along slots 18 of a magnetic core,
the distal ends of the guides 23 (i.e. the ends nearest core
face 17) are moved radially toward the closed ends of slots
18 due to the inter-action of the guides and wedges during
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the insertion process.
During operation of the apparatus of Fig. 6, the stator
assembly 10 is positioned as illustrated with the face 16
of the core resting on the abutment surface or ledge 62 of
adaptor 41. Thereafter, when the apparatus 30 is actuated,
power means (such as an air or hydraulic cylinder) will drive
the cam 36 upwardly and cause the movable blades 33 to ex-
pand radially outwardly in order to establish therebetween
restricted pathways for slot wedges, with such restricted
pathways being in alignment with the pathways 64 established
along the wedge guide housing 32 and also being in alignment
with the stator slots 18. Since the blades 33 expand radially
outwardly, they insure that winding end turns 37 and 38 will
be moved or held outwardly away from the path of the moving
wedges.
After the cam 36 has been actuated to expand the
movable blades 33, the wedge pushers 35 are actuated so as
to move the wedges 21 axially upwardly along the wedge guide
housing 32, and along the extended paths established between
adjacent pairs of the expandable blades 33. While the wedges
are advancing between adjacent blades 33, the lead end of the
wedges engage guide wire 23 and follow the guide wire as the
insulator enters a slot 18. Then, as the wedge pushers
continue to move the wedges axially along the core slots,
the wedges are constrained to remain within the slot 18
by tooth tips 66, 67 (see Figs. 2-4) or slot sidewalls.
Thus, the wedges resiliently deflect the guide wires 23
and cause them to move radially toward the closed ends of
the core slots. Concurrently, the guide wires 23 constrain
the wedges 21 to remain toward the bore of the stator assembly
(which in turn is defined by adjacent tooth tips 66, 67 etc.).
The guide wires 23 are so dimensioned and have strength
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and flexibility characteristics such that they may be de-
flected by the advancing wedges and yet not be so stiff as
to tear the wedges. The shape of the tube 42 is such that
the surface portions thereof between slots 57 prevent wedges
from being forced out of the slots 18 past the tooth tips
66, 67. After a predetermined number of wedges have been
inserted in a corresponding number of preselected slots 18
of the stator assembly 10 (as determined by the slots that
are to share wire segments to different phases); the stator
assembly is removed from the guide tube 42. As this time,
the wedges 21 will snap or slip to the desired position there-
of adjacent to wire segments 14 as previously discussed
hereinabove.
Although it has not been previously mentioned, it will
be understood that clamp arms may be provided (as has been
done herebefore) to hold the stator assembly 10 clamped
against the abutment surface or ledge 62 during the end turn
forming and wedge inserting process that has just been
described.
While two preferred embodiments of the present in-
vention have been described as preferred specific forms, it
will be understood that still other forms might be utilized,
all as will be readily apparent to persons of ordinary skill
in the art. Moreover, it will be readily apparent and
obvious to those skilled in the art that changes and modifi-
cations may be made without departing from the invention.
It is therefore intended in the appended claims to cover all
such changes and modifications that fall within the spirit
and scope of the invention.
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