Method of and apparatus for winding and inserting coils in slots of stator or rotor lamination assemblies of electrical machines

Apparatus and method for winding and inserting coils in slots of a stator or rotor lamination assembly, the coils being produceable on a former, said apparatus and method comprising a transfer tool for transferring said coils from said former onto an insertion tool, said transfer tool comprising annularly arranged parallel bars; and said insertion tool, comprising correspondingly annularly arranged parallel insertion blades, cover strip blades, and an axially mobile insertion ram, said insertion tool being able to introduce said coils into said slots, wherein in said apparatus, said bars are adapted to abut onto the radially internal side of said insertion blades still during at least a part of the insertion operation, and are movable together with said ram.

This invention relates to a method and apparatus for winding and inserting 
coils in slots of a stator or rotor lamination assembly of an electrical 
machine, the coils being produced on a former and transferred by means of 
a transfer tool onto an insertion tool, said transfer tool comprising 
annularly arranged parallel blades, said insertion tool comprising 
correspondingly annularly arranged parallel insertion blades, cover strip 
blades, and an axially mobile insertion ram, this tool being able to 
introduce said coils into said slots. 
A method and apparatus suitable for carrying out a method of the aforesaid 
kind are known from, e.g., German published specification No. 1 589 860. 
Methods are also known wherein winding is carried out directly into an 
insertion tool without using a transfer tool (see German published 
specification No. 19 38 184). However, the latter requires specific 
conditions, as regards the construction of the machine, which are not 
always present. 
Usually, coils are suspended between stationary insertion blades onto which 
a stator or rotor lamination assembly is placed (see, e.g., U.S. Pat. No. 
3 324 536). To facilitate placing of a said assembly, it is known to use 
aligning elements (e.g., a so-called aligning star) whereby a stator 
lamination assembly and an insertion tool are centred and aligned in the 
circumferential direction before they come into engagement (see U.S. Pat. 
No. 3 893 490 and German laid-open specification No. 28 08 049). The 
setting and removal of such an aligning element, however, involves 
additional manipulations or mechanical arrangements and movements. 
With specific size ratios between wire thickness and gap width between 
insertion blades, and also other disadvantageous factors, wire turns tend 
to jam in the gaps, when they are advanced along stationary blades by an 
insertion ram. One known remedy is to make one in each case of two 
insertion blades (which guide a specific coil strand) move together with 
said ram (see German Pat. No. 1 918 485). In this respect, it is known in 
the first phase of the insertion operation to move all the insertion 
blades together with said ram, then adjust the free ends of the insertion 
blades approximately to the level of the opposite end face of a stator 
lamination assembly, and finally carry out the remaining insertion stroke 
with said ram alone, this travelling in known manner to beyond the free 
ends of the insertion blades (see German laid-open specification No. 20 06 
526 and German published specification No. 26 30 183). But, if all the 
insertion blades travel with the insertion ram, the centering and the 
precise and careful placing of the stator lamination assembly on the 
insertion blades presents difficulties. If for this reason, longer 
insertion blades are selected than are needed for receiving the previously 
wound coils, then a result is (where the free ends of the insertion blades 
travel only just to the opposite stator side with the insertion ram) that 
at the end of the insertion operation there is still a very long 
displacement travel for said ram with the insertion blades already 
stationary, so that wire jamming may result. Alternatively, it is 
necessary to travel with the free ends of the insertion blades in the 
first instance far beyond the stator lamination assembly, and to withdraw 
the blades again by this same length whilst the insertion ram is held fast 
temporarily only before said ram can carry out the last part of the 
insertion stroke. 
It would be conceivable to make the insertion blades run from the opposite 
side to the insertion ram and into a stator bore, and to withdraw those 
blades at the insertion operation (see German Utility Model No. 79 30 007, 
FIG. 3). However, in that case, when inserting coils with a large number 
of turns (i.e. with a high coil structure between the insertion blades), 
those coils have to be removed already from the stator bore, after a 
proportion of the turns has been drawn through the stator bore and then 
has to be spread out radially in the region of the end turns, but another 
part of the turns is not yet drawn completely through the stator bore. 
After withdrawal of the insertion blades, as the travel of the insertion 
ram continues, these last-mentioned parts of the turns may be damaged on 
the sharp edges of the stator lamination assembly which are now no longer 
covered by the blades. 
One object of the present invention is to provide a method and an apparatus 
of the kind initially specified, whereby conditions at the end of the 
insertion operation can be improved over the state of the art, and (if 
desired) simpler centering of a stator relative to the insertion tool can 
be achieved at the same time. 
A first aspect of the present invention provides a method of winding and 
inserting coils in slots of a stator or rotor lamination assembly, the 
coils being producable on a former and transferable by means of a transfer 
tool onto an insertion tool, said transfer tool comprising annularly 
arranged parallel bars, said insertion tool comprising correspondingly 
annularly arranged parallel insertion blades, cover strip blades, and an 
axially mobile insertion ram, this tool being able to introduce said coils 
into said slots, wherein in said method, bars abut on the radially 
internal side of said insertion blades still during at least a part of the 
insertion operation, and are moved together with said ram. 
A second aspect of the present invention provides apparatus for winding and 
inserting coils in slots of a stator or rotation lamination assembly, the 
coils being producable on a former, said apparatus comprising a transfer 
tool for transferring said coils from said former onto an insertion tool, 
said transfer tool comprising annularly arranged parallel bars; and said 
insertion tool, comprising correspondingly annularly arranged parallel 
insertion blades, cover strip blades, and an axially mobile insertion ram, 
said insertion tool being able to introduce said coils into said slots, 
wherein in said apparatus, said bars are adapted to abut onto the radially 
internal side of said insertion blades still during at least a part of the 
insertion operation, and are movable together with said ram. 
One advantage of the invention is making the transfer tool (which normally 
only serves to transfer coils from the winder to the insertion tool) carry 
out additionally an important function in the insertion operation, i.e. 
the bars of the transfer tool serve as releasable extensions of the 
insertion blades. In this way, the result can be achieved that (depending 
on existing pre-requisites in each individual case as regards centering a 
said assembly, clamping of wire turns between insertion blades, height of 
the coil body in the insertion tool, length of the insertion blades, 
height of a said assembly, etc.) optimum insertion conditions can be 
provided in each case. The insertion blades can be run smoothly to the 
opposite face of a said assembly, or vice versa a said assembly pushed 
correspondingly far onto the insertion blades. There can be no risk that 
the coil wires will be damaged on the sharp edges of a said assembly. 
In one preferred embodiment of the invention, the transfer tool or a 
plurality of transfer tools in succession can be brought each with a said 
assembly placed thereon and coils suspended between upwardly directed said 
bars to below said insertion tool, and then moved downwardly from above 
together with said insertion ram at the insertion operation. This method 
allows the use of a plurality of simple and inexpensive transfer tools 
which all co-operate with a single common insertion tool. It is novel to 
transport to the insertion station with the transfer tools not only the 
coils but at the same time stator or rotor lamination assemblies already 
placed on the bars (see in contrast German laid-open specification No. 28 
25 557). This advantage can even be further developed by arranging that in 
the course of the winding and slipping-over of coils onto the transfer 
tool holding the stator or rotor lamination assembly, winding ends are 
connected to connecting terminals arranged in insulated manner on the 
stator or rotor lamination assembly (see in this connection German 
published specification No. 22 19 764 and German laid-open specification 
No. 23 20 865). This possibility is afforded only because according to the 
proposal provided hereinbefore the stator or rotor lamination assembly is 
already on the bars of the transfer tool during the winding operation. 
The advantage achieved by the invention of facilitating centering and 
bringing together of the stator or rotor lamination assembly with the 
insertion tool without additional manipulation of an aligning star is 
noticeable not only in the case of automatic winding and insertion 
apparatus but also with simpler insertion apparatus. In such cases, the 
free ends of the insertion blades can be withdrawn almost to the free ends 
of the cover strip blades in the starting position, and even if (in a 
manner commonly employed) for easier placing of the stator or rotor 
lamination assembly, the central longitudinal axis of the insertion tool 
is directed upwards at an inclination. Even a high stator or rotor 
lamination assembly can be put-on in an inclined position and held 
securely once the bars of the transfer tool have been brought into 
engagement with the insertion blades as prolongations of said blades.

The transfer tool 12 shown in FIGS. 1A, 1B, 1C can be applied to an 
automatic winding and insertion apparatus having a construction described 
in German laid-open specification 28 25 557. But, as a departure from that 
installation, FIGS. 1A, 1B, 1C hereof show coils 10 which can be slipped 
from a winding former (not shown) into transfer tool 12, which comprises a 
ring of parallel bars 14 whose free ends are directed upwardly, and on 
each of which a stator lamination assembly 16 has been placed before coils 
10 are introduced into gaps between bars 14. Transfer tool 12 has a base 
18 that holds bars 14 and deals with pre-centering and aligning of stator 
lamination assembly 16 through a suitable diameter region and projections 
engaging into slots of assembly 16, or utilises other alignment elements 
than projections. Base 18 holds assembly 16 by means of a support 20, and 
is adapted to travel through connection with a conveyor apparatus (e.g. a 
conveyor belt or a turntable) between a winding station and an insertion 
station and possibly stations for placing assembly 16 onto transfer tool 
12 and for removing the stator after insertion of coils 10. Transfer tool 
12 is lowerable at least at the insertion station, while the stator 
lamination assembly 16 is held fast there by a holding device 22. 
At an insertion station, laden transfer tool 12 arrives (see FIG. 1A) below 
a conventionally constructed insertion tool 24 comprising insertion blades 
26, cover strip blades 28, an insertion ram 30, and cover strip slides 32 
(see FIG. 1B). One aspect of the invention provides that (with respect to 
the common central longitudinal axis of transfer tool 12 and of insertion 
tool 24) the central longitudinal axes of individual bars 14 and of 
associated insertion blades 26 are situated in the same radial planes; 
i.e., bars 14 and the respective associated insertion blades 26 
substantially are in alignment with one another, although radially 
slightly offset relatively to one another because of mutual engagement. 
Bars 14 and also insertion blades 26, however, are suitable for covering 
sharp edges of the bars or teeth of the stator lamination assembly 16 
between slots of assembly 16 in each case so that wires of coils 10 cannot 
be damaged thereon. 
In the embodiment according to FIGS. 1A, 1B, 1C, all insertion blades 26 
travel uniformly with one another, because their rear ends (see FIG. 1B) 
are connected securely to a blade holder 36, which can be axially advanced 
and withdrawn through a tube 38 and a reciprocating drive known per se. 
Independently of insertion blades 26, the insertion ram 30 can be axially 
advanced and withdrawn by a reciprocating drive (not shown) via a rod 40 
guided in tube 38. Axial drives of insertion blades 26 and of insertion 
ram 30 can be so controlled that during the first part of the insertion 
stroke (which leads from the position shown in FIG. 1A substantially into 
the position shown in FIG. 1B) the insertion ram 30 and insertion blades 
26 advance jointly. Cover strip slides 32 are advanced in known manner, so 
that insulating cover strips, which are guided between cover strip blades 
28, are pushed into the stator slots. 
In FIG. 1B, the free ends of insertion blades 26 lead relatively to 
insertion ram 30 only by the distance which is optimal for completing the 
insertion operation in the last phase thereof in accordance with the 
particular conditions. As a rule, the height of the structure of the coils 
10 in the insertion of transfer tool designated as "h" in FIG. 1B will be 
greater than the amount by which the free ends of insertion blades 26 
project beyond insertion ram 30. However, even for those coil wire turns 
which precede in the insertion operation there is no risk of damage on the 
sharp edges of the stator lamination assembly, because these are covered 
also by bars 14 which are in engagement with insertion blades 26. After 
the coil turns which precede in the insertion operation as in FIG. 1B have 
been drawn completely through the stator bore and then the insertion 
blades 26 cover the stator teeth as far as the ends thereof, transfer tool 
12 can be withdrawn completely downwards from the position shown in FIG. 
1B, so that the turns of the coils 10 which lead in the insertion 
operation can be fanned out radially to form the overhangs or end turns. 
After withdrawal of transfer tool 12, the insertion blades 26 remain in the 
positions as in FIG. 1B, but insertion ram 30 continues its downwardly 
directed insertion stroke to beyond the position shown in FIG. 1C and the 
lower end face of the stator lamination assembly, whereat all the wire 
turns are moved out of the gaps between insertion blades 26 and to beyond 
free ends thereof and shaped-out radially. In known manner, the cover 
strip slides 32 are advanced to such an extent when that happens that at 
the end the cover strips have reached their predetermined position in the 
slots of the stator lamination assembly. The parts of insertion tool 24 
are then again withdrawn upwardly into the starting position shown in FIG. 
1A, whereupon the stator provided with inserted coils 10 is moved away, 
and the next transfer tool 12 with stator lamination assembly 16 and coils 
10 as in FIG. 1A is brought into the insertion station. 
The insertion operation according to FIGS. 1A to 1C can be further promoted 
somewhat by providing that cover strip blades 28 (which in the first 
instance advance from the position shown in FIG. 1A by displacement of 
holder 39 of insertion tool 24 along guide columns 41 up to abutment on 
the stator lamination assembly as in FIG. 1B) after introduction of the 
forward ends of the cover strips into the slots of the stator lamination 
assembly are withdrawn again somewhat, so that the rear winding ends of 
coils 10 can be brought closer to the stator bore and as a result the 
coils can be inserted further before transfer tool 12 is withdrawn from 
insertion tool 24. 
A special axial drive is needed for transfer tool 12, for moving bars 14 
out of the position shown in FIG. 1B downwardly off the free ends of 
insertion blades 26. This special drive, however, need be activated only 
for this withdrawing movement. During the first phase of the insertion 
operation (wherein insertion blades 26 and bars 14 of transfer tool 12 
travel jointly with insertion ram 30), the transfer tool 12 can be 
entrained by the insertion blades 26 or insertion ram 30. But, the special 
axial drive of transfer tool 12 during the insertion operation also 
affords the possibility of providing part of the total insertion force 
required for inserting the coils into the stator slots, this being 
greatest in the first phase of the insertion operation, in that the wires 
are entrained by the bars 14 as a result of friction. Also, there is the 
further possibility of moving bars 14 already during the first phase of 
the insertion operation somewhat more quickly than insertion ram 30 and 
insertion blades 26, so that, when the speeds are suitably adapted to each 
other, the free ends of bars 14 are withdrawn from the free ends of 
insertion blades 26, just at the instant when the latter have reached 
their end position shown in FIG. 1B and in which they remain stationary. 
FIG. 1B also shows that it would not be sufficient to use only bars 14 and 
not insertion blades 26 for guiding coils 10 in the insertion operation. 
With a relatively large coil structure, it is necessary (for example when 
the position shown in FIG. 1B is reached in the insertion operation) to 
withdraw transfer tool 12 entirely so that the coil turns which precede in 
the insertion operation are left free and can spread out radially. If 
insertion blades 26 were not still additionally present at that time, the 
coil turns which are at the rear in the insertion operation would be slid 
along the sharp edges of the stator lamination assembly, which would no 
longer be covered and would very probably be damaged. 
Depending on particular kinds of employment, not all slots of the stator 
lamination assembly are occupied with coils always. It may also happen 
that only specific coils, and not all the coils, to be inserted in a 
stator lamination assembly tend to jam between the insertion blades or the 
bars of the transfer tool. The invention optionally includes the 
possibility (depending on the particular circumstances in the individual 
case) of constructing some or all insertion blades to be co-travelling 
and/or making them co-operate with transfer tool bars serving as 
prolongations. 
In FIG. 1B, the stator lamination assembly 16 is connected to an insulating 
ring 42, which can be provided in known manner with connecting terminals 
44 (see FIG. 4), to which the winding ends are applied and secured. This 
operation as FIG. 4 shows can be substantially simplified with the 
transfer tool shown in FIG. 1. FIG. 4 shows a transfer tool 12 with a 
stator lamination assembly 16 already placed on a stand in a winding 
station below a winding former 46. A winding nozzle 48 circulating about 
former 46 produces on former 46 the coil turns, which in this example are 
pushed by axially reciprocatingly operated stripper elements 50 (as per 
German Pat. No. 23 09 837) down from former 46 and between bars 14 of 
transfer tool 12. Depending on the position of winding nozzle 48, the wire 
being wound has a well-defined position between nozzle 48 and former 46, 
and can be taken up by a clamping device 52 with two clamping tongs 52a 
and 52b arranged with spacing between these tongs and a cutting device 
known per se (not shown here), and brought thus held taut to the 
connecting terminals 44, and secured thereto e.g. by means of a plunger 54 
situated between clamping tongs 52a and 52b. This advantageous procedure 
is made possible by stator lamination assembly 16 (or at least the ring 
42) being already in a specific position on transfer tool 12 when winding 
into the transfer tool 12. Because the illustrated high ring 42 does not 
allow bandaging of the end turns, either a further concentric ring can be 
inserted additionally which holds the end turns outside the stator bore, 
or a ring can be used which is so flat that it does not hinder bandaging. 
FIGS. 2 and 3 show various constructions of the insertion blades 26 and 
bars 14 which are to be brought into engagement with one another. 
In FIG. 2, the insertion blades 26 have at their radially internal side a 
groove into which in this example round bars 14 of transfer tool 12 
engage. In the engagement position, the bars 14 stabilise insertion blades 
26. The diameters of bars 14 are so chosen that the gap width between the 
bars corresponds substantially to the gap width between insertion blades 
26. The spacing between bars 14 may even be somewhat smaller than the gap 
width between insertion blades 26. 
In FIG. 3A and FIG. 3B, the insertion blades 26 and bars 14 of transfer 
tool 12 (except for the free ends in each case) have substantially the 
same cross-section which engages about the stator teeth. Only at the free 
ends are the cross-sections of insertion blades 26 set back and reduced, 
so that each cross-section fits into a substantially U-shaped recess 56 in 
the free ends of bars 14. In this region, the insertion blades 26 do not 
have the small radially outwardly directed projections which engage about 
the stator teeth. 
Many other constructional forms and cross-sections for insertion blades 26 
and bars 14 are available for allowing them to be brought into engagement 
in axial alignment with one another, but care is to be taken that where 
possible the free ends of insertion blades 26 retain their protective and 
guiding function, and that the free ends of bars 14 do not form any 
obstacle when slipping the wire turns from winding former 46 onto transfer 
tool 12. FIG. 1B indicates it is possible for bars 14 to engage with their 
free ends in insertion ram 30 in the first phase of the insertion 
operation, in which insertion ram 30 is moved synchronously with bars 14. 
FIGS. 5A to 5D show a simpler apparatus wherein a manually operatable 
transfer tool 58 is used. The insertion tool 24 in FIG. 5 can have 
basically the same construction as insertion tool 24 of FIG. 1. The above 
remarks also apply to bars 14 of transfer tool 58. 
Otherwise than in FIG. 1, FIGS. 5A, 5B, 5C, 5D show insertion blades 26 
directed upwardly at an inclination or perpendicularly, and insertion ram 
30 moves upwardly from below at the insertion stroke. Previously wound 
coils 10 are carried with the use of transfer tool 58 (provided with a 
handle 60) to insertion tool 24, whose insertion blades 26 in the starting 
position according to FIG. 5A take up preferably a position withdrawn 
substantially almost to the free ends of cover strip blades 28. Transfer 
tool 48 is brought into engagement with insertion tool 24, and at first 
left in this position shown in FIG. 5A. Coils 10 are transferred between 
insertion blades 26 and cover strip blades 28, but also remain between 
bars 14, which in the example here are inserted into insertion ram 30. 
Without the aid of an additional aligning star, a stator lamination 
assembly 16 can then be placed on the insertion tool 24 (shown in FIG. 
5D). The base plate 62 of transfer tool 58 can serve the purpose of an 
aligning star by suitable cross-sectional form. Transfer tool 58 coupled 
with insertion tool 24 also provides secure support even for a relatively 
high stator lamination assembly on an obliquely upwardly directed 
insertion tool 24 with insertion blades 26 substantially withdrawn 
according to FIGS. 5A and 5B. 
During the insertion operation, the stator lamination assembly 16 is held 
in a manner known per se by a holding device 64 (see FIG. 5B). During the 
first part of the insertion stroke, the insertion blades 26 and insertion 
ram 30 travel jointly upwards, transfer tool 58 also being carried along 
in the movement. In the position in FIG. 5C, the drive of insertion blades 
26 stops, and insertion ram 30 also stands still. Transfer tool 58 is then 
drawn out upwards, and then insertion ram 30 completes the insertion 
stroke in the usual way, and there is no longer a risk of damaging the 
coil wires on the sharp edges of the stator lamination assembly, because 
insertion blades 26 have already advanced as far as the top edge of the 
stator in the first phase of the insertion stroke. At the end, the 
position shown in FIG. 5D is achieved, and subsequently insertion ram 30 
and insertion blades 26 are withdrawn into the starting position, and the 
stator taken off so that a new working cycle can begin.