Wave winding mat for an electric machine and method of manufacturing thereof

Abstract

Wave winding mat (1) for insertion into radial slots of a stator or rotor of an electrical machine, comprising a plurality of interwoven individual wires (4), each having an individual wire thickness (D), which are bent several times in opposite directions in such a way that parallel legs (3) of the individual wires (4), which are designed for positioning within the slots, are connected by winding heads (2), the winding heads (2) each having two obliquely extending winding head sections (20, 21) with an intermediate winding head tip (22), are connected by winding heads (2), wherein the winding heads (2) each have two obliquely extending winding head sections (20, 21) with a winding head tip (22) located therebetween, wherein the individual wires (4) are arranged one behind the other in a longitudinal direction of the wave winding mat (1), at least one wire exchange position and at least one intermediate area (5) without a wire exchange position, wherein a repositioning of an individual wire (4') is provided at the wire exchange position; characterised in that that the repositioning of all other individual wires within one pole of a phase is only offset by one slot in the same sequence, wherein the height of the winding head (2') in the wire exchange position is increased by the individual wire thickness (D) compared to the winding heads (2) without wire exchange position.

Description

[0001] WAVE WINDING MAT FOR AN ELECTRIC MACHINE AND METHOD OF MANUFACTURING THEREOF

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a wave winding mat for insertion into radial slots of a stator or rotor of an electrical machine and to a method of manufacturing a wave winding mat for insertion into radial slots of a stator or rotor of an electrical machine.

[0004] BACKGROUND

[0005] Wave winding mats as a form of coil winding can, for example, be produced by winding individual wires in wire packs around a winding former. If the individual wires have a rectangular cross-section, they are referred to as flat wire windings. This method results in a flat, wave-shaped coil winding, which is also known as a wave winding and has roof-shaped winding heads that are arranged between two straight wire legs in the course of the individual wires of the wave winding. When fed into a rotor or stator with a cylindrical rotor or stator body, the wave winding with the superimposed individual wires is drawn into slots with its legs and the winding heads project axially beyond the rotor or stator body and form the offset of the individual wires over various slots. Coil windings produced in this way allow coils of several electrical circuits to be inserted into a stator or rotor body at once, so that three-phase operation of an electric motor is possible, for example.

[0006] So-called phase jumps in the wave winding mat are known as a measure for reducing the circular currents within the stator or rotor, whereby the conductors of a phase change their position once or several times in the circumferential direction. This allows better symmetry to be achieved in the circumferential direction of the wave winding mat in the stator or rotor. With phase jumps, the wave winding mat can be made completely symmetrical, apart from the first pole, which can reduce circulating currents by over 90 %.

[0007] Due to their winding, the coil windings known from the prior art require a relatively large amount of installation space to produce the desired mat geometry as soon as wire exchange positions are introduced into the wave winding mat, as the coil width is increased by two or more slots. This results in a winding head that is locally much higher than the rest of the wave winding mat, making the wave winding mat larger overall. However, the available installation space is very limited, especially when used in car engines.

[0008] SUMMARY

[0009] It is therefore the task of the present disclosure to provide a wave winding mat for insertion into a stator or rotor which has layer jumps without greatly increasing the circumference of the wave winding mat in a detrimental manner.

[0010] Advantageous embodiments and further developments are the subject of the claims, the accompanying description, and the figure.

[0011] According to one aspect of the disclosure, a wave winding mat is provided for insertion into radial slots of a stator or rotor of an electric machine. The electrical machine can be, for example, a motor for a car. It is conceivable that the manufactured wave winding mat is not drawn directly into a rotor or stator, but first into a mounting tool, which ultimately transfers the wave winding mat into a rotor or stator body. The wave winding mat comprises a large number of interwoven individual wires. Each individual wire has an individual wire thickness. The individual wires are bent several times in opposite directions so that parallel legs of the individual wires, which are designed for positioning within the slots, are connected by winding heads. The legs are dimensioned in such a way that they can be drawn precisely into the slots of the stator or rotor. The winding heads each have two inclined winding head sections with a winding head tip in between. This results in a roof-shape of the winding heads. The individual wires are arranged one behind the other in a longitudinal direction of the wave winding mat. The wave winding mat also has at least one wire exchange position and at least one intermediate area without a wire exchange position. Repositioning of a individual wire is provided at the wire exchange position. This means that the individual wire is repositioned in relation to the other individual wires with regard to its height position. The repositioning of the remaining individual wires of the pole is limited to a displacement by one slot in the stator. The height of the winding head in the wire exchange position is increased by the wire thickness D compared to the winding heads without wire exchange position. This is a result of the fact that the individual wire on which repositioning is provided runs over the other individual wires for this repositioning in the winding head area. As a result, its winding head is raised above the others. Geometrically, there is then always an individual wire in the winding mat that spans the centre individual wires of a pole.

[0012] According to an embodiment of the disclosure, the number of wire exchange positions is smaller by a factor of 1 than a number of holes q of the stator. For a symmetrical winding structure in tangential direction, the necessary number of wire exchange positions - without considering the first pole - is always smaller by a factor of 1 than the number of holes q of the stator. The number of holes q describes how many slots are available per strand and pole in the stator or rotor. The number of holes q can be calculated using the formula

[0013] N q = - -

[0014] 2p x m

[0015] To calculate the number of holes q, the number of slots N, the number of poles (2x number of pole pairs p) and the number of phases m are required. Geometrically, there is always a individual wire in the winding mat that spans the centre individual wires of a pole. This design of the wave winding mat makes it possible to obtain a topology that is also favourable for higher numbers of holes q.

[0016] The advantage of this design is that the position of the spanned individual wires is only changed by one slot. As a result, the wave winding mat is only increased in its height by the individual wire thickness of the spanning individual wire. In this way, the space required for the shaft winding mat is kept as small as possible.

[0017] This arrangement results from a positive wire exchange.

[0018] The positive wire jump can be calculated as follows: w = wo + q - 1, whereby the following applies for the other wires: w = wo - 1. wo can be calculated by multiplying the number of phases and the number of holes.

[0019] The repositioning of the individual wire for the wire exchange always has a change in the jump width of q-1 and the remaining individual wires of this joint structure reduce their previous coil width by 1.

[0020] With a positive wire exchange, the height of the winding head can be advantageously kept lower than with a negative one, resulting in installation space advantages. However, it is also possible to provide a negative wire jump, which means that the wire jump position is in the last individual wire per pole per phase. The negative wire jump can be calculated as follows: w = wo - q + 1 and w = wo + 1 then applies accordingly for the other wires.

[0021] The disadvantage of negative wire exchange in terms of installation space is that the coil width of the spanned wires is increased, which means that they require more installation space. In comparison, positive wire exchange reduces the coil width of the spanned wires, resulting in a locally smaller winding head.

[0022] According to a further embodiment, the wire geometry has a turn in the winding head. The torsion resulting in the turn at this position is advantageous for geometries with a greater width than depth and / or thickness. Depending on whether there is torsion of the wire in the winding head, the wire thickness D describes either the width of the wire in the case of an upright winding or the thickness of the wire in the case of a turn in the winding head. Typically, stator windings have a greater wire width than height, which results in an installation space advantage for a geometry with torsion.

[0023] According to a further embodiment, the number of legs per slot corresponds to an integer multiple of the number of holes q. Preferably, the number corresponds to twice the number of holes q, which places the wire exchange position in a circumferential area of the stator.

[0024] For example, an advantageous design results in three wire jumps with a number of holes of 4. With four double layers of the wave winding mat in the wound state in the stator or rotor, there are three transition areas in which the wire jumps are located and four equally sized mat parts. This means that the layer jumps are arranged next to each other and are all located in the area in which the start and end wires of the wave winding mat are also arranged. In this area, the installation space is already larger due to the start and end wires, so that no additional installation space needs to be planned for the layer jumps. The layer jumps are all in a compact arrangement and the deviating winding head height does not have a negative effect on the overall geometry in the stator or rotor.

[0025] According to a further embodiment, all the legs of the individual wires have the same length. The individual wires for which a layer exchange is provided also have the same leg length as the other individual wires. This is advantageous in order to ensure that the wave winding mat can be drawn into the slots of the rotor or stator with a precise fit and especially in relation to the total wire length this is advantageous for phase symmetry.

[0026] According to a further embodiment, all intermediate areas have the same length. This offers the advantage that a symmetrical arrangement of the wire exchange positions within the wave winding mat can be realised. This also offers the advantage that the arrangement can be predetermined across several layers in the stator or rotor in the wound state and can be placed in the same area, so that a space-saving arrangement can be ensured because additional space only needs to be provided there. This also ensures that the wave winding mat has full tangential symmetry with an exception of the first pole.

[0027] According to a further embodiment, the number of winding heads that are skipped by the winding head of the wire exchange position in the intermediate area corresponds to an odd number. As a result, the wire jumps are present in the wave winding mat in such a way that they are only present on one side of the stator or rotor. This means that the layer exchange positions can all be arranged on one side, the so-called "lead end" of the stator. This ensures that the overall height is not increased in a detrimental way. This is also advantageous for maintaining the symmetry of the wave winding mat within the stator or rotor. However, it is also possible that wire jumps are present on both ends of the stator or rotor for further arrangements of the coil winding. This can be calculated using the following formula:

[0028] NH — XT

[0029] HBT =

[0030] XT + 1

[0031] HBT is defined as the number of winding heads to be skipped, NH is defined as the number of winding heads and XT is the number of layer exchange positions. If HBT assumes an odd value, the layer exchange positions are arranged at one end of the stator or rotor. If the number for HBT is even, the layer exchange positions are arranged at both ends of the stator.

[0032] According to a further embodiment, the wave winding mat has at least two double layers. A winding of a individual wire to form a winding head and a leg before the winding head and a leg after the winding head can be referred to as a double layer. A double layer can have any number of winding heads and corresponding legs. The double layers can be wound in series. In the stator or rotor, it can then be useful to install the wave winding mat rolled up in such a way that several double layers are arranged one behind the other. Preferably, the wave winding mat has at least two double layers, particularly preferably four. This design has various electromagnetic advantages, as the symmetry and the structure in the stator are positively influenced. The double layers and wire jumps can be matched to each other in such a way that they are aligned with the stator or rotor in order to ensure the highest possible symmetry and the greatest possible efficiency.

[0033] According to a further aspect of the disclosure, there is provided a method of manufacturing a wave winding mat according to any one of the preceding claims. The method comprises several steps which can be repeated as desired and customised: Firstly, individual wires are interwoven to form an intermediate region without a wire exchange position. In the area of a wire exchange position, a layer exchange of an individual wire is carried out so that it skips the other individual wires once. The individual wire spans the other individual wires of the same pole of the phase and increases the height of the wave winding mat by its wire thickness. Then, a position exchange of an individual wire in a wire exchange position is carried out, wherein this individual wire undergoes a change in the regular coil width of q-1. The remaining individual wires of the pole only undergo a change in the regular coil width by one regular stator slot.

[0034] In this way, the pattern of the legs in the slots that serve as conductors can be reorganised. This can reduce energy losses in the stator or rotor.

[0035] In the following, an embodiment of the disclosure is described in more detail with reference to the attached drawing.

[0036] It is shown:

[0037] BRIEF DESCRIPTION OF THE DRAWING

[0038] Fig. 1 a schematic illustration of a section of a wave winding mat.

[0039] DETAILED DESCRIPTION

[0040] Figure 1 shows an exemplary section of a wave winding mat 1. It has winding heads 2 and legs 3. The legs 3 are suitable for being inserted into radial slots of a stator or rotor. It also has a winding head 2', which is created by exchanging the layers of a individual wire 4'. The layer exchange can be provided according to a defined sequence over the course of the wave winding mat 1. In this exemplary illustration, the wave winding mat 1 is formed from four individual wires 4. Winding is used to form the winding heads 2 following the legs 3, which in turn are followed by legs 3, resulting in a continuously wound wave winding mat 1. Each winding head 2 has two diagonally extending winding head sections 20, 21 and a winding head tip 22.

[0041] The original position of the four individual wires 4 in the arrangement 1-2-3-4 (1st, 2nd, 3rd, 4th individual wire) one behind the other is changed by the first layer exchange in such a way that the order of the arrangement then corresponds to 4-1-2-3. This means that the 4th individual wire changes its position by three slots as a result of the layer exchange, while the other individual wires change their position by one slot. This sequence can be maintained for a predeterminable number of windings until a second layer swap is carried out. This creates an intermediate area 5 in which no wire jumps are realised and therefore there are no deviations from the standard coil width. The second layer exchange is again only realised by shifting, so that the sequence of the arrangement of the individual wires now corresponds to 3-4-1-2. After a third layer exchange, the arrangement then corresponds to 4-1-2-3. Preferably, the layer exchange positions with the winding heads 2' are distributed over the wave winding mat 1 in such a way that a symmetrical overall picture is created and the layer exchange positions of the wave winding mat 1 in the rolled-up state, drawn into the stator or rotor, are in the same area as the start and end wires. The layer exchange is realised in a manner that the winding head 2' is only increased by one wire thickness D compared to the winding heads 2 in the area of its winding head tip 22'. This arrangement proves to be particularly space-saving, as the increase in the winding head 2' compared to the other winding heads 2 is only minimal.

[0042] Reference signs

[0043] 1 Wave winding mat

[0044] 2, 2' Winding head

[0045] 20,21 Winding head section

[0046] 22, 22' Winding head tip

[0047] 3 Leg

[0048] 4, 4' Individual wire

[0049] 5 Intermediate area

[0050] D Wire gauge

Claims

CLAIMS:

1. Wave winding mat (1) for insertion into radial slots of a stator or rotor of an electrical machine, comprising: a plurality of interwoven individual wires (4), each having an individual wire thickness (D), which are bent several times in opposite directions in such a way that parallel legs (3) of the individual wires (4), which are designed for positioning within the slots, are connected by winding heads (2), the winding heads (2) each having two obliquely extending winding head sections (20, 21) with an intermediate winding head tip (22), are connected by winding heads (2), wherein the winding heads (2) each have two obliquely extending winding head sections (20, 21) with a winding head tip (22) located therebetween, wherein the individual wires (4) are arranged one behind the other in a longitudinal direction of the wave winding mat (1); at least one wire exchange position; and at least one intermediate area (5) without a wire exchange position; wherein a repositioning of an individual wire (4') is provided at the wire exchange position; characterised in that that the repositioning of all other individual wires within one pole of a phase is only offset by one slot in the same sequence, wherein the height of the winding head (2') in the wire exchange position is increased by the individual wire thickness (D) compared to the winding heads (2) without wire exchange position.

2. Wave winding mat (1) according to claim 1, characterised in that the number of wire exchange positions is smaller by a factor of 1 than a number of holes q of the stator.

3. Wave winding mat (1) according to claim 1, characterised in that the wire geometry has a turn in the winding head.

4. Wave winding mat (1) according to claim 1, characterised in that the number of legs (3) per slot corresponds to an integer multiple of the number of holes q.

5. Wave winding mat (1) according to claim 4, characterised in that all legs (3) of the individual wires (4, 4') have the same length.

6. Wave winding mat (1) according to claim 5, characterised in that all intermediate areas (5) have the same length.

7. Wave winding mat (1) according to claim 1, characterised in that the number of winding heads (2) skipped by the winding head (2') of the wire exchange position corresponds to an odd number.

8. Wave winding mat (1) according to claim 1, characterised in that the wave winding mat (1) has at least two double layers.

9. A method of manufacturing a wave winding mat (1) for insertion into radial slots of a stator or rotor of an electric machine according to claim 1, comprising the steps in any order: winding the individual wires (4) into an intermediate area (5) without wire exchange position; and carrying out a position exchange of an individual wire (4') in a wire exchange position, wherein the change in the regular coil width of the individual wire (4') is q-1 and the change in the regular coil width of the remaining individual wires (4) concerns only one regular stator slot.

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