The invention relates to a manufacturing device for a coil for deflecting a coil, wherein a preformed body is provided for the deflection, wherein the preformed body has a first portion which represents a circular arc, and has a second portion which represents a chord.
Electric machines often consist of a stator and a rotor, wherein the stator has stator grooves in which a stator winding is incorporated, and wherein the stator winding has coils.
Stators or stator segments of dynamo-electric machines have coils in particular in a layered laminated core in order to drive a working machine through electromagnetic interaction with a rotor, or to generate electrical energy through the driven rotor. Coils are positioned in grooves of a laminated core of a dynamo-electric machine.
The formation of end windings by the coils (formed or toothed coils) is difficult, particularly in the case of dynamo-electric machines of a large power class (greater than 1 MW). An example of this are generators for wind turbines and tidal power plants, which are used to convert mechanical energy into electrical energy. High-performance motors can be found, for example, in rail motive drives, compressors or pumps.
Electric machines in the higher power range are often designed with so-called preformed coils, as are known, for example, from DE 195 29 970 C1. These are preformed conductor bundles that are wrapped with insulating material, which is usually in the form of strips. To produce a preformed coil, a raw coil is usually first wound and then spread out in such a way that it can be inserted into grooves in the stator.
The coil of a stator winding of an electric machine has, for example, a number of windings that are wound together with a number of layers of mica tape, onto which in turn a number of layers of a cover tape is wound, wherein the coil is designed as a three-dimensional preformed coil.
In the case of coils designed as preformed coils, it is known to first produce a flat coil which, due to its shape, is usually referred to as a race-track loop (two long straight lines which are connected to one another by two semicircular curved portions in particular). This coil is formed into the preformed coil by a forming process. In the case of preformed coils, so-called preformed plates can be used to form the end windings when drawing the coils. However, this is no longer possible with coils with very short winding heads due to machine technology limitations, and an optimal/clean winding head shape is no longer given or cannot be manufactured without plates, A further problem can arise from drawing, if this causes the individual windings of a coil to move away from each other again.
JP 2013 251 995 A discloses a manufacturing device for a coil which provides a preformed body for deflecting a coil, wherein the preformed body has a first portion which represents an circular arc, and a second portion which represents a chord. This device forms the preamble of claim 1. The preformed body for bending the coil is circular in the region in which the coil to be shaped or its windings rest thereon. In the region where there is no coil or winding resting thereon, as shown in
Proceeding from this, it is therefore an object of the invention to enable improved drawing of the preformed coil with reduced bulging or spreading.
A solution to the problem results from a manufacturing device according to claim 1 to claim 3. A further solution to the problem results from a method according to claims 4 to 8. A further solution to the problem results from a stator according to claim 9 or 10. Design embodiments of these solutions also result according to one of the variants of design embodiments described below in the description.
In a manufacturing device for a col, for deflecting a con, a preformed body is provided for the deflection, wherein the preformed body has a first portion which represents a circular arc, and a second portion which represents a chord, wherein both portions are provided for resting thereon the coil. The first portion and the second portion are provided so that the coil is guided on these during bending and the coil finally rests against the first portion and the second portion as a result of the bending. The coil is bent in particular at an angle of 180°, i.e. in such a way that the coil can be inserted into a first groove of a stator of an electric machine and can also be inserted into a further groove. In this way, the coil can be guided to an end face of the stator and returned after being deflected by 180°. The deflection of the coil on an end face of the laminated core of the stator forms a winding overhang.
According to the invention, the first portion is provided for resting thereon the coil, and the second portion is also provided for resting thereon the coil. The first portion and the second portion adjoin each other. The first portion and the second portion have a height that is at least equal to the height of the coil.
In a preferred embodiment, a manufacturing device according to the invention for a coil is characterized in that the first portion has a circumferential angle of between 80° and 120°, preferably between 90° and 110°, particularly preferably approximately 105°, and the second portion has a circumferential angle of between 90° and 130°, preferably between 100° and 120°, particularly preferably approximately 115°. These dimensions give particularly good results when bending to form the winding head and prevent the individual layers from spreading. The circle chord preforms the end winding. The chord in the preformed body is advantageous if no plates can be used in the forming.
The same applies to a further embodiment of a preformed body according to the invention, which is aligned during bending of the coil so that the chord of the second portion in relation to the coil longitudinal direction has an angle of between 5° and 45°, preferably between 10° and 30°, more preferably between 15° and 25°, particularly preferably approximately 20°. It is unimportant how the preformed body is designed where there are no windings or other coil elements in contact during bending. It is only relevant that where the windings or the coil elements are in contact, there is first a circular shape (a piece of a circle or a circle segment) and then a subsequent straight line for forming the favorable shape. It is also possible that there is first a straight line (a piece of straight line) followed by a piece of a circle (circle segment).
The production device makes it possible to achieve a short end windings length using a winding tool (preformed body) for preforming preformed coils. Shorter electric machines can be built by shortening the end windings length. This is advantageous, for example, in wind power generators or in ship propulsion systems. The winding tool (preformed body) with the different portions for resting thereon the coil during bending also makes it possible to pre-bend a coil in such a way that when the coil is subsequently drawn to the desired shape of the winding head, the windings of the coil are spread apart in the region of the winding head can be reduced at least, With a preformed body (winding tool) that is not round, as with standard winding, but with a preformed body that has a slope (chord), the drawing of the coil can be positively influenced. This slope pre-shapes the part of the coil before it is drawn during winding, and thus replaces solutions to problems such as tapping windings of the coil to size. After drawing, the shape of the end windings corresponds in particular to that of a coil that was manufactured or should have been manufactured with preformed plates, without generating any additional effort.
According to a method for producing a coil, wherein the coil has a multiplicity of windings, the coil is bent over a preformed body, wherein a first portion is formed, which represents an circular arc, and a second portion is formed, which represents a chord. In the case of the coil, the first portion is formed and the second portion is formed by the preformed body. In particular, the first portion and the second portion follow one another directly. The coil thus forms the shape of the preformed body.
According to one design embodiment of the method, the preformed body has a first preformed body portion, which represents an circular arc, and a second preformed body portion, which represents a chord. The shape of the preformed body and the shape of the shaped (bent) coil correspond to each other.
In one embodiment of the method, the coil is drawn in such a manner that the coil in the second portion with a chord shape has windings of which the mutual spacing is smaller than a mutual spacing with a circular arc shape in the second portion. This circular arc shape in the second portion represents the known production. In the known production, the first portion and the second portion are configured as circular arcs, wherein both circular arcs form a common circular arc, and thus there are actually no two portions and they are also not known.
Due to the second portion with the shape of a chord, the windings of the coil no longer bend as a result of the drawing, as in a predefined circular arc shape of the coil before the drawing. This allows the end windings to be made more compact, for example, Insulating the coil is also made easier in the region of the end windings.
In one embodiment of the method, a continuous gradient is formed by the coil, by being drawn, in the region of the end windings. This is due to the fact that the windings at least no longer spread out as much. The slope results from a radial view from the inside to the outside.
When carrying out the method, one of the production devices described is used in particular.
A stator of an electric machine has a coil which is pre-bent in the shape of a circular arc and a chord. Such a pre-bent or preformed coil is used in the manufacture of the stator. The use of coils of this type results in improved production of the winding overhang of the electric machine. To produce the end windings, the pre-bent (preformed) coils are drawn. To produce the electric machine, coils are used in particular, which are prefabricated according to one of the methods described.
The invention and further advantageous configurations of the invention are explained in more detail below on the basis of exemplary embodiments presented in principle. It is shown in:
The illustration according to
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The illustration according to
In contrast to
It is easy to see that here the first portion 17 has a circumferential angle of 105′ and the second portion 18 has a circumferential angle of 115°, These angles determine the shape of the coil 7 produced, while the region on the left in
It can also be seen that the preformed body 9 when bending the coil 7 is aligned so that the chord 20 of the second portion 18 is at an angle of 20° with respect to the longitudinal direction of the coil—as here in
The illustration according to
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Number | Date | Country | Kind |
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20199130.4 | Sep 2020 | EP | regional |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2021/076220 | 9/23/2021 | WO |