DE102021130918A1 - Process for manufacturing an electrical machine, mandrel and electrical machine - Google Patents

Abstract

Method for producing an electrical machine, comprising a base body which extends along an axis of rotation and has a multiplicity of circumferentially distributed grooves for arranging conductor material, comprising the steps: - providing a base body and arranging conductor material in at least one groove; - applying a force in a radial direction on the conductor material for compacting and/or aligning the conductor material;- applying impregnation material to the conductor material in the compacted/aligned state.

Description

The present invention relates to a method for producing an electrical machine, a mandrel and an electrical machine such as is used, for example, as a traction motor in electrically operated motor vehicles.

Electric motors or electrical machines of the type in question have windings which are impregnated with materials such as resins. Here it is to be ensured as far as possible that the resin is distributed completely or evenly within the winding, in particular that no cavities or the like are formed. This would reduce the thermal conduction from the winding to the adjacent laminated core. In addition, the mechanical stability of the entire arrangement is reduced. The winding wires could move during operation, which can also lead to acoustic abnormalities. In order to enable targeted impregnation and to keep the reworking effort as low as possible, the DE 10 2019 121 956 A1 proposes an impregnation device for impregnating components of an electrical machine, comprising a resin application device for applying a resin to a first area of a component rotating in the impregnation device and a sealing gas flow generating device for directing a sealing gas flow to at least one second area of the component adjoining the first area, to prevent flow of resin from the first region to or across the second region. However, even this does not ensure that the distribution of the resin within the winding is as complete and even as possible.

It is therefore an object of the present invention to specify a method for producing an electrical machine, a mandrel and an electrical machine which enable optimal impregnation of the winding with resin, or generally with an impregnating material.

This object is achieved by a method according to claim 1, a mandrel according to claim 11 and by an electrical machine according to claim 12. Further advantages and features emerge from the subclaims and the description and the attached figures.

• - Bereitstellen eines Grundkörpers und Anordnen von Leitermaterial in zumindest einer Nut;
• - Aufbringen einer Kraft in radialer Richtung auf das Leitermaterial zum Verdichten und/oder Ausrichten des Leitermaterials in der Nut;
• - Aufbringen von Imprägniermaterial auf das Leitermaterial im verdichteten/ausgerichteten Zustand.

According to the invention, a method for producing an electrical machine comprises a base body which extends along an axis of rotation and has a multiplicity of circumferentially distributed slots for arranging a winding or conductor material, the steps:

• - Providing a base body and arranging conductor material in at least one slot;
• - applying a force in a radial direction to the conductor material to compress and/or align the conductor material in the groove;
• - Application of impregnation material to the conductor material in the compacted/aligned state.

By applying the force, the conductor material is aligned or compressed within the slot. The conductor material can be wire, such as classic copper wire (having a round or substantially round cross-section). Alternatively, the conductor material can also be formed wire. This typically has a square, in particular a rectangular, cross section. According to one embodiment, the long side of the “rectangle” essentially corresponds to a width of the groove. Irrespective of the actual configuration of the conductor material, any gaps, intermediate spaces or gaps between the (formed) wires or also deformations of the (formed) wires can advantageously be minimized in the present case by applying the force. Straight shaped wires shaped into hairpins often have dimensional tolerances, for example they are a bit "twisted" or "crooked". This can be corrected or compensated for very well using the present method. Alignment and/or compression results in optimal impregnation, since the capillary effect, which is responsible for the distribution of the impregnation material between the (formed) wires or within the winding, can have the best possible effect. The form wires are compressed/aligned via the application of force, which reduces existing cavities and gaps. Larger empty spaces are avoided, the distances between the (forming) wires are adjusted so that during impregnation the capillary effect pulls the resin or the impregnating material much more effectively into the (small) gaps. The result is a better and more even filling of the grooves and an increase in the degree of filling of the grooves with resin/impregnation material. This is advantageous, among other things, for the heat dissipation to the laminated core, the acoustics, the partial discharge behavior, etc.

According to a preferred embodiment, the base body is a stator body. The stator body includes a laminated core, for example. The aforementioned grooves are formed or arranged on an inner peripheral surface of the laminated core. Alternatively, the base body can also be a rotor body. This correspondingly has the grooves on its outer circumferential surface and includes flat if typically a laminated core. The method is described below such that the base body is a stator body. The features and advantages apply analogously and correspondingly to a rotor body.

According to a preferred embodiment, the conductor material is formed by hairpins, which are introduced axially into the slots. In this case, shaped wire is formed into a so-called "hairpin". The slot openings, usually called "slot slots", of the stator slots are narrowed towards the axis of rotation, which means that the preformed hairpins can only be introduced or pushed into the slots axially.

• - Aufbringen einer Kraft auf das in der Nut angeordnete Leitermaterial, welche radial von der Rotationsachse weg gerichtet ist.

Conveniently, the method includes the step:

• - Application of a force to the conductor material arranged in the groove, which is directed radially away from the axis of rotation.

The conductor material located in the slot is expediently pressed against the yoke of the stator body via the introduction of force. In addition to the aforementioned avoidance of cavities, etc., the outer diameter of the end winding at the slot exit is expediently increased. An increased distance from the rotor is particularly advantageous since unintentional contact during operation can be avoided. In addition, the risk of electrical flashovers, which can result from an insufficient air gap, is minimized. In the case of a rotor body, the force would have to be directed radially towards the axis of rotation.

• - Verwenden eines Hilfselements zum Aufbringen der Kraft.

Zweckmäßigerweise ist das Hilfselement ein leistenartiges, bevorzugt längliches, Element, vorliegend auch Tragelement oder Schieber genannt, welches gemäß einer Ausführungsform zumindest so lang wie die jeweilige Nut ist. Zweckmäßigerweise kann damit vollflächig und gleichmäßig entlang der jeweiligen Nut die Kraft aufgebracht werden. Damit kann eine gleichmäßige Komprimierung/Verdichtung/Ausrichtung entlang der gesamten Nut erreicht werden, wodurch sichergestellt wird, dass das Leitermaterial über die gesamte Länge optimal ausgerichtet und verdichtet ist.According to a preferred embodiment, the method comprises the step:

• - Using an auxiliary element to apply the force.

The auxiliary element is expediently a strip-like, preferably elongate, element, also referred to here as a support element or slide, which, according to one embodiment, is at least as long as the respective groove. The force can expediently be applied over the entire surface and evenly along the respective groove. This enables uniform compression/densification/alignment to be achieved along the entire slot, ensuring that the conductor material is optimally aligned and compacted over the entire length.

• - Halten des Grundkörpers beim Imprägnieren mittels einer Vielzahl von Hilfselementen.

Indem der Grundköper beim Imprägnieren, insbesondere ausschließlich, über die Hilfselemente gehalten wird, können Harzrückstände an der inneren oder der äußeren Umfangsfläche des Grundkörpers vermieden werden. Würde der Grundkörper dort über Greifer oder dergleichen gehalten werden, würde der Kapillareffekt dazu führen, dass in diese Bereiche (Berühr- oder Kontaktstellen der Greifer) ungewollt Harz vordringt. Dieses müsste nachträglich aufwendig entfernt werden.According to a preferred embodiment, the method comprises the step:

• - Holding the body during impregnation by means of a variety of auxiliary elements.

By holding the base body during impregnation, in particular exclusively by the auxiliary elements, resin residues on the inner or outer peripheral surface of the base body can be avoided. If the base body were held there by grippers or the like, the capillary effect would lead to resin penetrating into these areas (touching or contact points of the grippers) unintentionally. This would have to be removed at a later date.

A large number of auxiliary elements are preferably used, so that a simultaneous application of force in all grooves can advantageously be made possible.

• - Verwenden eines Spanndorns, umfassend eine Vielzahl von umfänglich angeordneten Tragelementen, welche radial verfahrbar sind, zum Aufspannen des Grundkörpers.

According to one embodiment, the method comprises the step:

• - Use of a mandrel comprising a plurality of circumferentially arranged support elements, which are radially movable, for clamping the base body.

The support elements correspond to the aforementioned auxiliary elements. Advantageously, the base body, in this case particularly preferably the stator body, is held by the mandrel during impregnation. Since the supporting elements of the mandrel can be moved radially, the conductor material arranged in the grooves can be compressed or densified. The mandrel therefore expediently not only holds the base body, but at the same time also enables the conductor material to be compressed in the groove or grooves. The mandrel is expediently designed to allow the base body to be turned or rotated about its axis of rotation.

The base body is expediently held exclusively or in particular exclusively by means of the mandrel.

• - Aufbringen des Imprägniermaterials mittels Träufelimprägnierung.

Conveniently, the method includes the step:

• - Application of the impregnation material by means of trickle impregnation.

During trickle impregnation, the base body is rotated around its own axis, cf. the aforementioned axis of rotation, by means of the mandrel. The base body can be heated, for example, by means of convection, infrared radiation or induction. During the rotation, the preferably low-viscosity impregnation material is dripped on with the aid of a dosing system, advantageously through a plurality of nozzles at different positions. Due to the capillary effect, the resin penetrates the winding and is distributed. In the present case, the distribution is optimized in particular by the capillary effect can work optimally through the alignment or compression of the winding.

The impregnation material is, in particular, a resin which is intended for the stated purpose. According to preferred embodiments, 1K and 2K, cold-curing or heat-curing epoxy resin systems, polyester or polyesterimide resins are used as the impregnating or insulating material.

The trickling is characterized by an advantageously low use of material. In addition, the application is ideal for 2-component impregnation materials, which enable rapid curing even at low temperatures and thus enable the investment and operating costs in production to be reduced.

According to an alternative embodiment, the impregnation material is applied by means of dip impregnation. Other impregnation processes that are not explicitly listed here can also be used expediently.

• - Anordnen eines Isolationspapiers in der zumindest einen Nut derart, dass es im Bereich der Nutöffnung bzw. im Bereich des Nutschlitzes überlappt.

According to a preferred embodiment, the method comprises the step:

• - Arranging an insulating paper in the at least one slot in such a way that it overlaps in the area of the slot opening or in the area of the slot.

It has been found that this type of slot insulation is well suited for the present method. The slot insulation where the force is introduced into the conductor material is multi-layered, in particular double-layered, and in particular also movable, which means that the slot insulation or the insulation of the conductor material is not damaged when the force is introduced.

The invention also relates to a mandrel comprising a large number of radially arranged support elements, which are designed to accommodate a rotor body or stator body of an electrical machine, the support elements being designed for at least regional arrangement in the slots of the rotor body or stator body, and the support elements are designed to be movable into the slots in such a way that conductor material arranged in the slots can be compressed.

If the mandrel is designed to hold a rotor body, the holding elements can be moved radially inwards, in the case of a stator body radially outwards.

Otherwise, the advantages and features mentioned in connection with the method apply analogously and correspondingly or vice versa.

The invention further relates to an electrical machine, comprising a rotor and/or stator, which are manufactured using the method according to the invention.

The conductor material arranged in the groove can be pressed against the respective yoke and compressed or densified by the slides, auxiliary or supporting elements, which can engage or move into the grooves of the respective base body. This aligns the (form) wires and minimizes any gaps, gaps, etc. Blowholes and the like can be avoided during impregnation, which enables optimal heat dissipation into the laminated core. In addition, the winding overhang outside diameter (in the case of a stator body) at the slot exit is advantageously increased. The acoustic behavior is optimized because the entire arrangement is mechanically stabilized.

Further advantages and features emerge from the following description of an embodiment of the method with reference to the attached figures.

• 1: eine Teilansicht eines Statorkörpers im Schnitt zum Veranschaulichen des Grundproblems;
• 2: die im Wesentlichen aus der 1 bekannte Anordnung, wobei das Aufbringen einer Kraft in radialer Richtung gezeigt ist;
• 3: eine schematische Ansicht einer Nut sowie die Anordnung eines Isolationspapiers.

Show it:

• 1 13 is a partial sectional view of a stator body to illustrate the basic problem;
• 2 : which essentially from the 1 known arrangement, wherein the application of a force is shown in the radial direction;
• 3 : a schematic view of a groove and the arrangement of an insulating paper.

1 shows a stator body 10 in a schematic partial view, with three slots 20 being visible in the present case. The base body or stator body 10 and the slots 20 extend along an axis of rotation R, ie in the present case into the plane of the drawing. The grooves 20 essentially have a rectangular cross section. The grooves 20 are tapered in the area of the groove openings 22 . Conductor material is arranged in the grooves 20, see reference number 12. In the present case, a plurality of hairpins can be seen schematically in section. The forming wire from which the hairpins are formed has a substantially rectangular cross section. The hairpins are arranged by being pushed in along the axis of rotation R. It is shown schematically here that the shaped wires do not lie optimally on one another, but are arranged slightly twisted or crookedly etc. relative to one another. Through the radial up bringing a force to the conductor material 12, this can be eliminated with advantage, cf 2 .

2 shows the essentially from the 1 known arrangement. It is shown schematically that slides, auxiliary or support elements 30 move into the grooves 20 in such a way that the conductor material 12 is compressed, compacted or aligned. Any gaps or spaces between the strands of conductor material 12 are minimized. As a result, the capillary effect, which brings about the distribution of the impregnating material in the grooves and between the conductor material 12, can have an optimal effect.

3 shows a schematic view of a groove 20 in cross section. Insulating paper 24 is shown here, which is introduced into slot 20 before conductor material 12 is arranged. In the present case, the insulating paper 24 is formed in two layers in the area of the slot opening 22 . The ends of the insulating paper 24 lie loosely on one another here. It can thus advantageously move when the force is introduced, as outlined by the arrow, and is not damaged.

Reference List

10

Base body, rotor body, stator body

12

conductor material

20

groove

22

Groove opening, groove slot

24

insulation paper

30

Auxiliary element, support element, slider

R

axis of rotation

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102019121956 A1 [0002]

Claims (12)

Method for manufacturing an electrical machine, comprising a base body (10) which extends along an axis of rotation (R) and has a multiplicity of circumferentially distributed grooves (20) for arranging conductor material (12), including the steps: - Providing a base body (10) and arranging conductor material (12) in at least one groove (20); - Applying a force in the radial direction to the conductor material (12) for compacting and/or aligning the conductor material (12); - Application of impregnating material to the conductor material (12) in the compacted/aligned state. procedure after claim 1 , wherein the base body (10) is a stator body. procedure after claim 1 or 2 , wherein the conductor material (12) are hairpins, which are introduced axially into the grooves (20). Method according to one of the preceding claims, comprising the step: - Application of a force to the groove (20) arranged conductor material, which is directed radially away from the axis of rotation. Method according to one of the preceding claims, comprising the step: - Using at least one auxiliary element (30) for applying the force. procedure after claim 5 , comprising the step: - holding the base body (10) during impregnation by means of a plurality of auxiliary elements (30). Procedure according to one of Claims 5 until 6 , comprising the step of: - using a mandrel, comprising a multiplicity of supporting elements (30) arranged on the circumference, which can be moved radially, for clamping the base body (10). procedure after claim 7 , comprising the step: - Holding the base body, in particular exclusively, by means of the mandrel. Method according to one of the preceding claims, comprising the step: - Application of the impregnation material by means of trickle impregnation. Method according to one of the preceding claims, comprising the step: - Arranging an insulating paper in the at least one groove (20) in such a way that it overlaps in the area of the groove opening (22). mandrel, comprising a large number of radially arranged support elements (30) which are designed to accommodate a rotor body (10) or stator body (10) of an electrical machine, wherein the support elements (30) are designed for at least regional arrangement in the slots (20) of the rotor body (10) or the stator body (10), and wherein the support elements (30) are designed to be movable into the slots (20) in such a way that conductor material (12) arranged in the slots (20) can be compressed. Electrical machine comprising a rotor and / or stator, which by a method according to any one of Claims 1 until 10 is made.

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