The invention relates to coil winding in general and more specifically to a method for winding a coil for electric machines, and a coil wound according to this method.
Concentrated coils are used in windings of quite a wide class of electric machines. A well-designed electric machine is often characterized by a high slot-fill factor providing high thermal conductivity inside the slot that improves the heat removal from the conductors to the iron cores. High slot-fill factor can be achieved when there is little of insulation, impregnation material or air between the conductors in the slot and there is no coil turns sticking-out sideways. For many machines the optimal shape of the coil is a rectangular or a parallelogram shape following the shape of the slots and making possible insertion of the coils into the slots.
To make a solid consolidated coil one usually uses a form on which the coil is wound. The common practice is doing the winding as a continuous process, winding layer after layer moving up and down the form. This practice is described in e.g. EP0920107 A2 and US2005/0236921 A1. The results of such a process is, however, not optimal since either some turns of the coil will stick out or the end wire should be bent to be led out of the center of the coil.
There is therefore a need for a method and a system to overcome the above mentioned problems.
The present invention solves the problems of the prior art and makes possible production of a improved concentrated coil by changing the winding process from the conventional continuous process to a process including two main stages involving winding the coil's wire in two opposite directions.
The objectives are achieved according to the invention by a method as defined in claim 1 and a coil as defined in claim 7 wound according to the said method.
A number of non-exhaustive embodiments, variants or alternatives of the invention are defined by the dependent claims.
In a first aspect of the present invention a method is provided for winding a coil for electric machines, wherein the coil is arranged with a plurality of layers and a plurality of levels, wherein the method comprises the following steps: placing a wire against a form, leaving a first length of the wire and a second length of the wire extending from the form, wherein the first length has a first end and the second length has a second end; winding the first length in a first direction round the form, such that the first end of the first length is ending in an outer layer of the plurality of layers; winding the second length in a second direction round the form, wherein the second direction is opposite the first direction, wherein the second end of the second length is ending in an outer layer of the plurality of layers, wherein all layers and levels of the coil are filled.
In one embodiment, the method further comprises a step for deciding on a coil winding geometry.
In one embodiment, the method further comprises a step for calculating the first length and the second length of the wire adapted for the decided coil winding geometry, and such that the first length and the second length are together a total length of the wire.
In one embodiment, winding the first length comprises rotating the form while the second length is fasten to the form using fastening means.
In one embodiment, winding the second length comprises rotating the form while the first length is already wound and hold fast around the form.
In one embodiment, winding the second length comprises rotating the form while the first length is fasten to the form using fastening means.
In one embodiment, winding the second length comprises revolving means for holding the end of the second length around the form.
In one embodiment, winding the first length comprises revolving means for holding the end of the first length around the form.
In one embodiment, winding the second length is done in a first stage, and winding the first length is done in a second stage.
In one embodiment, winding the first and second lengths comprises filling the plurality of layers and the plurality of levels such that all layers have an equal number of levels.
In a second aspect, the present invention relates to a coil wound using the method describe above comprising a wire with a first end and a second end and a form, wherein the coil is configured with a plurality of layers and a plurality of levels, wherein the wire first end and second end are both ending in an outer layer from the plurality of layers.
In one embodiment, the wire of the coil is a solid wire.
In one embodiment, the wire of the coil comprises a plurality of sub-wire.
In one embodiment, the coil has a substantially rectangular cross section.
In one embodiment, the coil has a substantially parallelogram cross section.
The present invention provides a technological advantage over known methods for winding a coil by winding a wire with two ends in a plurality of layers round a form in two different directions in that it results in the two ends of the wire ending in an outer layer of the coil plurality of layers.
The present invention provides several further advantageous effects:
The above and further features of the invention are set forth with particularity in the appended claims and together with advantages thereof will become clearer from consideration of the following detailed description of exemplary embodiments of the invention given with reference to the accompanying drawings.
The invention will be further described below in connection with exemplary embodiments which are schematically shown in the drawings, wherein:
The following reference numbers and signs refer to the drawings:
Various aspects of the disclosure are described more fully hereinafter with reference to the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Based on the teachings herein one skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the disclosure disclosed herein, whether implemented independently of or combined with any other aspect of the disclosure. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.
The following definitions will be used:
Layers: is a plurality of adjacent wire turns wound along the form radial direction as shown in
Levels: is defined as the number of overlapping layers round the form, as shown in
The invention will be further describe in connection with exemplary embodiments which are schematically shown in the drawings.
In
Prior to starting winding the coil, it can be decided on the desired geometrical arrangement of the coil that is to be achieved. This means the user decides on the number of layers and levels to be wound with the first length 4 of the wire, and the number of layers and levels to be wound by the second length 6 of the wire. Based on the desired geometrical arrangement required, first length 4 and second length 6 are determined, which together provide the total length of the wire to make a complete coil.
According to the present invention, the wire is placed against the form 5, such that the first length 4 and the second length 6 are extending from the form 5 as shown in
The wire is wound in a two stages method.
In a first stage of the winding method, as shown in
In the first stage of the winding method, the rotation of the form 5 relative to the spool 3 can be achieved using different arrangements. In one possible alternative arrangement, as already described in the paragraph above and illustrated in
In a second stage, as shown in
In the second stage of the winding method, the motion of the form 5 relative to the means 10 can be achieved using different arrangements. In one possible alternative arrangement, as already described in the paragraph above and illustrated in
According to the present invention, all steps for first and second stage of the winding method, as described above, can be performed by automated manipulators or robots.
In such an embodiment as shown in
First, in such an embodiment as shown in
Second, in such an embodiment as shown in
Also in this embodiment, as shown in
In another embodiment of the present invention, the wire can be fastened to the form using means 7 for fastening the wire as shown in
The present invention makes it possible for the first end 1 and second end 2 of the wire to end in the outer layer of the coil as shown in
Further,
It should be understood that the methods described above are just examples of possible implementation of the general principle disclosed. Other embodiments are possible.
The invention according to the application finds use in winding coil for electric machines.
Number | Date | Country | Kind |
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19160767.0 | Mar 2019 | EP | regional |
Filing Document | Filing Date | Country | Kind |
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PCT/NO2020/050057 | 3/4/2020 | WO | 00 |