Slot wedge and method of using the same

Abstract

A slot wedge (1) having a shank region (2) and a joining region (3) perpendicular to the shank region, the slot wedge radially closing a slot (10) in an electric machine. The joining region (3) joins with a deformation region (12) of a slot insulating material (11). A closing cap (4) can fix the slot wedge (1) in the slot (10). Protrusions (5, 6) that limit the creepage distance (21) can be arranged on the shank region (2) or, if applicable, on the closing cap (4).

Description

Technical Field

[0001] The present invention relates to electric machines and, more precisely, to a closed design of slots for windings of electric machines. Background Art

[0002] Various winding techniques are known in connection with the windings of electric machines. For example, in the development of high-performance electric motors, wave windings have advantages over concentrated windings in terms of the achievable power and over hairpin designs in terms of the number of required welded joints and in terms of skin and proximity effects. A problem with electric machines with wave windings is the slot closure, that is to say the closure of the slots in the stator or rotor that accommodate the windings of the electric machine. This slot closure is necessary due to the high voltages acting in the electric machine and also due to the relevant regulations, but is not easy to achieve due to the radial introduction of the windings into the slots.

[0003] For example, it is known to introduce the windings radially from the inside into the slots of the stator of the electric machine. The slots are initially open to the air gap of the electric machine. If the slots remain open, it is more difficult to maintain the distance required for high voltage insulation; this also reduces the overall insulation of the electric machine. This is solved by closing the slots with slot wedges.

[0004] Pre-closing the slot opening with conventional slot wedges is not without problems. Firstly, sufficient overlap between the slot wedge and the actual slot insulation material must always be ensured. This is particularly difficult in applications with a large number of slots and therefore with very narrow slots, since the slot insulation material, such as paper, will sometimes need to be laid several times over the entire width of the slot to obtain the required distance for high-voltage insulation. The subsequent closing of the slot with previously introduced slot insulation material also presents problems, since it is generally not possible to deform the slot insulation material in the narrow slot during the series connection. Summary of the invention

[0005] The object is therefore to specify a slot wedge which can reliably close the slot in a simple manner.

[0006] The corresponding method should also be specified.

[0007] The slot wedge according to the invention has a shank region and a joining region perpendicular to the shank region. If the slot wedge is inserted into the slot, the shank region is oriented in the radial direction relative to the electric machine and thus in the direction in which the slot extends. The joining region perpendicular to the shank region is arranged to engage with the slot insulation material in the slot, i.e. to interlock with the slot insulation material in the slot. In this way, a reliable closure of the slot is ensured and also a sufficient overlap with the slot insulation material is ensured.

[0008] In one embodiment, the joining area is designed in a plate-like manner. The plate-like design increases the tolerance for a secure joining with the slot insulation material and makes the closing of the slot by the slot wedge more reliable.

[0009] In one embodiment, a closing cap is provided on the shaft region. The closing cap is spaced apart from the joining region. When the joining region joins with the slot insulation material in the interior of the slot, the closing cap closes the slot on the outside, that is, closes the slot towards the air gap of the electric machine.

[0010] The slot wedge can be designed in such a way that the distance required for the high-voltage insulation is ensured in a simple and reliable manner by defining a sufficiently long creepage distance through the slot wedge. If the slot wedge has a closing cover, a corresponding projection which limits this creepage distance can be formed on the closing cover for this purpose. Alternatively, the projection which limits this creepage distance can be provided on the shaft region. A combination of the two options just mentioned is also conceivable.

[0011] The method according to the present invention is used to close a slot after a winding has been introduced into the slot, and the method uses the slot wedge according to the present invention as described above. The method performs at least the following steps.

[0012] First, the slot insulation material is introduced into the slot. Secondly, the winding is introduced into the slot. Then, the slot insulation material is deformed so that at least two opposing regions of the slot insulation material are oriented toward the central axis of the slot; the central axis extends in the radial direction relative to the electric machine. Then, a slot wedge according to the invention is introduced into the slot. This is done in such a way that the engagement region of the slot wedge engages with at least two opposing regions of the slot insulation material resulting from the previous deformation of the slot insulation material. This can be done, for example, in such a way that the region initially formed by the deformation of the slot insulation material remains outside the slot, the engagement region engages with the deformed slot insulation material in the axial direction, i.e. in a direction perpendicular to the radial extent of the slot, and then the slot insulation material and the slot wedge are placed together in a predetermined position in the slot. Alternatively, a sufficiently elastic slot insulation material can be used, the engagement region is inserted into the slot, the deformed slot insulation material is initially also pressed into the interior of the slot before the slot insulation material rebounds and thus reaches behind the engagement region, whereby the engagement region then engages with the slot insulation material.

[0013] In one embodiment, the slot wedge has a closing cover. When the slot wedge is introduced into the slot, the slot wedge is fixed by the closing cover, in particular transversely, ie perpendicularly to the central axis of the slot.

[0014] If projections are provided on the closing cap or on the shank region, the slot wedge inserted into the slot defines the creepage distance in the slot via these projections.

[0015] The slot wedge can be made of plastic, such as polyphenylene sulfide (PPS), preferably in one piece. A more elastic plastic also facilitates the radial insertion of the slot wedge into the slot, because when the engagement area passes through the deformation area of ​​the slot insulation material, the engagement area can then also be elastically deformed, thereby then springing back and thus interlocking with the slot insulation material. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The invention and its advantages are explained in more detail below with reference to the attached schematic diagram.

[0017] Figure 1 A first exemplary embodiment of a slot wedge according to the invention is shown.

[0018] Figure 2 The top view shows Figure 1 An exemplary embodiment of .

[0019] Figure 3 A second exemplary embodiment of a slot wedge according to the invention is shown.

[0020] Figure 4 The top view shows Figure 3 An exemplary embodiment of .

[0021] Figure 5 An example of closing of a slot according to the invention is shown.

[0022] Figure 6 Another example of closing of a slot according to the invention is shown.

[0023] The drawings represent only exemplary embodiments of the present invention and therefore should not be interpreted as limiting the present invention to the exemplary embodiments shown. DETAILED DESCRIPTION

[0024] Figure 1 An exemplary embodiment of a slot wedge 1 according to the invention is shown. The slot wedge 1 has a shank region 2 and a joining region 3 perpendicular to the shank region. In the example shown, the slot wedge 1 has a closing cap 4 which is attached to the shank region 2 and on which a projection 5 for limiting the creepage distance in the slot is formed.

[0025] Figure 2 The top view shows Figure 1 The components shown are already combined Figure 1 As can be seen here, the joining region 3 is plate-shaped.

[0026] Figure 3A further exemplary embodiment of a slot wedge 1 according to the invention is shown. The slot wedge 1 has a shank region 2 and a joining region 3 perpendicular to the shank region. In the example shown, the slot wedge 1 has a closing cap 4 attached to the shank region 2. In the example shown, a projection 6 is provided on the shank region 2, which serves to limit the creepage distance in the slot.

[0027] Figure 4 The top view shows Figure 3 The components shown are already combined Figure 3 As can be seen here, the joining region 3 is plate-shaped.

[0028] Figure 5 The various stages of closing the slot 10 in connection with the introduction of the winding 20 into the slot 10 are shown. The slot 10 and its central axis 100 are shown. The central axis 100 extends in a radial direction relative to the electric machine in which the slot 10 is provided in the stator or rotor; that is, the axis of rotation of the rotor of the electric machine is perpendicular to the drawing plane. In stage A, the slot insulation material 11 is introduced into the slot 10 and the winding 20 is already arranged in the slot 10. In stage B, the slot insulation material 11 is deformed so that a region 12 of the slot insulation material 11 is oriented towards the central axis 100. In stage C, Figure 1 A slot wedge 1 of the type shown in FIG. 1 is inserted into a slot 10. A creepage distance 21 is also schematically shown, which is defined by a projection 5 on the slot wedge 1. In the exemplary embodiment shown, the opening of the slot 10 is narrowed relative to the diameter of the slot 10. As a result, the closing cap 4 and thus the entire slot wedge 1 are held in the slot 10. However, it is also conceivable that the slot is not narrowed, but that the slot has a constant diameter, for example. In this case, the slot wedge can be held in the slot in a friction fit.

[0029] Figure 6 The various stages of closing the slot 10 in connection with the introduction of the winding 20 into the slot 10 are shown. The slot 10 and its central axis 100 are shown. The central axis 100 extends in a radial direction relative to the electric machine in which the slot 10 is provided in the stator or rotor; that is, the axis of rotation of the rotor of the electric machine is perpendicular to the drawing plane. In stage A, the slot insulation material 11 is introduced into the slot 10 and the winding 20 is already arranged in the slot 10. In stage B, the slot insulation material 11 is deformed so that a region 12 of the slot insulation material 11 is oriented towards the central axis 100. In stage C, Figure 3A slot wedge 1 of the type shown in FIG. 1 is inserted into a slot 10. A creepage distance 21 is also schematically shown, which is defined by a projection 6 on the slot wedge 1. In the exemplary embodiment shown, the opening of the slot 10 is narrowed relative to the diameter of the slot 10. As a result, the closure cap 4 and thus the entire slot wedge 1 are held in the slot 10. However, it is also conceivable that the slot is not narrowed, but that the slot has a constant diameter, for example. In this case, the slot wedge can be held in the slot in a friction fit.

[0030] Reference numerals list

[0031] 1 slot wedge

[0032] 2 Shaft area

[0033] 3 Joint area

[0034] 4 Closing cap

[0035] 5. Protrusion

[0036] 6. Protrusion

[0037] 10 slots

[0038] 11 slot insulation material

[0039] 12 (slot insulation material) area

[0040] 20 Winding

[0041] 21 Creepage distance

[0042] 100 (slot) central axis.

Claims

1. A slot wedge (1), comprising a shaft region (2) and a joining region (3) perpendicular to the shaft region (2); wherein: A protrusion (6) for limiting a creepage distance (21) is arranged on the shaft region (2); wherein a closing cover (4) is arranged on the shaft region (2).

2. The slot wedge (1) according to claim 1, wherein: The joining area (3) is plate-shaped.

3. The slot wedge (1) according to claim 1, wherein: A protrusion (5) for limiting the creepage distance (21) is provided on the closing cover (4).

4. A method for closing a groove (10), the method comprising at least the following steps: introducing a slot insulating material (11) into the slot (10); introducing a winding (20) into the slot (10); Deforming the slot insulating material (11) such that at least two opposing regions (12) of the slot insulating material (11) are oriented toward a central axis (100) of the slot (10); The slot wedge (1) according to one of claims 1 to 3 is introduced into the slot (10) such that the engagement region (3) of the slot wedge (1) engages with the at least two opposing regions (12) of the slot insulating material (11).

5. The method according to claim 4, wherein: The slot wedge (1) has a closing cover (4), and the closing cover (4) fixes the slot wedge (1) in the slot (10).

6. The method according to claim 5, wherein: A projection (5) is provided on the closing cover (4) for limiting the creepage distance (21) when the slot wedge (1) is introduced into the slot (10).

7. The method according to claim 4, wherein: A projection (6) is provided on the shank region (2) which limits the creepage distance (21) when the slot wedge (1) is introduced into the slot (10).

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