EP-4736300-A1 - FILLING A GROOVE WITH A TWO-COMPONENT DUROMER SYSTEM IN AN ELECTRIC MACHINE

Abstract

A groove closure (12) of a winding groove (1) of an electric machine is to be efficiently produced. For this purpose, a first component of a two-component duromer system is provided, magnetizable particles being added to the first component, and a second component of the two-component duromer system is provided, magnetizable particles being likewise added to the second component. The two components are mixed and are introduced into the groove (1) of the electric machine, where the components are cured.

Inventors

• Büttner, Klaus
• KATZENBERGER, TOBIAS
• KIRCHNER, FLORIAN
• KIRCHNER, KLAUS
• PLOCHMANN, Bastian
• WARMUTH, MATTHIAS

Assignees

• Innomotics GmbH

Dates

Publication Date

20260506

Application Date

20240610

Claims (15)

1. 1 . Method for filling a slot ( 1 ) of a stator of an electrical machine provided with a wire bundle ( 6 ), characterized by - Providing a first component of a two-component duromer system, wherein magnetizable particles are mixed into the first component, - Providing a second component of the two-component duromer system, wherein magnetizable particles are mixed into the second component, - Mixing the first component with the second component, - Inserting the mixed components into the groove ( 1 ) of the electrical machine and - Allowing the mixed components to harden in the groove ( 1 ) to form a duromer provided with the magnetizable particles.
2. 2. The method according to claim 1, wherein the first component of the two-component duromer system is a natural resin, an epoxy resin or a component of a two-component adhesive.
3. 3. Process according to claim 1, wherein the first component of the two-component thermoset system is formed on an isocyanate basis.
4. 4. The method of claim 1 or 2, wherein the second component comprises an amine.
5. 5. Process according to one of the preceding claims, wherein the magnetizable particles are mixed into both the first and the second component with at least 50 percent by weight, in particular 75 to 90 percent by weight.
6. 6. A method according to any one of the preceding claims, wherein the magnetizable particles originate from an iron powder.
7. 7. Process according to one of the preceding claims, wherein the first and second components are mixed in a ratio range of 1.2:1 to 1:0.8 and in particular in the ratio 1:1.
8. 8. Method according to one of the preceding claims, wherein the introduction of the mixed components into the groove (1) of the electrical machine is carried out by means of a paste dosing system.
9. 9. A method according to any one of the preceding claims, wherein the curing of the mixed components takes place largely at room temperature.
10. 10. Method according to one of the preceding claims, wherein during the introduction of the viscous duromer emulsion into the groove (1) of the electrical machine, a viscous strand (10) of the mixed components is applied to a wire bundle (6) in the groove (1).
11. 11. The method according to claim 10, wherein the wire bundle (6) is pressed in the direction of the groove base (3) immediately before the application of the viscous strand (10).
12. 12. The method according to claim 11, wherein after the application of the viscous strand (10), the wire bundle (6) in the groove (1) relaxes and a part of the strand (10) is pressed behind a groove projection (5) on the groove (1) to form a positive connection.
13. 13. Method according to one of the preceding claims, wherein the viscous strand (10) is pulled off flush with the surface after being introduced into the groove (1).
14. 14. Device for filling a slot (1) of a stator of an electrical machine provided with a wire bundle (6), characterized by - a mixing device for mixing a first component of a two-component duromer system, wherein magnetizable particles are mixed into the first component, and a second component of the two-component duromer system, wherein magnetizable particles are mixed into the second component, and - an application device for introducing the mixed components into the groove (1) of the electrical machine.
15. 15. Device according to claim 14, wherein the mixing device either - a first screw extruder ( 14 ) for conveying the first component, - a second screw extruder ( 15 ) for conveying the second component and - a mixer ( 17 ) for mixing the first component from the first screw extruder ( 14 ) with the second component from the second screw extruder ( 15 ) , or - has a static mixing tube for mixing both components.

Description

Description Groove filling using a two-component duromer system in an electric machine The present invention relates to a method for filling a groove of an electrical machine. Furthermore, the present invention relates to a corresponding device for filling such a groove. Low-voltage motors are typically manufactured with a round wire winding, which is wound into coils in advance using a flyer/template winder and then drawn into the laminated core with the respective slots in a fully automated process. The critical point here is always the slot gap, which is defined by the two adjacent slot teeth. This is significantly smaller than the slot itself, which ideally means that the magnetic circuits close more effectively, but the entire copper winding has to be drawn through this cross-sectional taper. In order to generate ideal magnetic field properties in the laminated core, the slot gap would have to be chosen to be so narrow that the slot gap width is smaller than the diameter of a single wire in the winding. However, this would lead to major problems in terms of manufacturing, as typical winding drawing-in processes can no longer be used. The current sheet metal geometries are a kind of compromise that takes both requirements into account. The slot gap is approx. the clear width of two to four individual wires ( diameter ) , whereby the copper bundle is partially compressed to this width by a suitable lamella guide during insertion and the disadvantage with regard to the magnetic circuit dimensioning remains acceptable . Especially for larger machines (medium voltage or high voltage motors) with higher requirements, the existing slot gap is then filled by means of a magnetic slot This involves magnetic iron particles of various designs, which are usually present in combination with a plastic as a "compound". This "compound" (filler particles = iron, matrix = plastic) is often prefabricated and used as slot wedges, which are mechanically inserted. This has the disadvantage that the slot closure can loosen and come off during operation of the machine due to vibrations and forces, thus blocking the rotor and causing the machine to fail. On the other hand, prefabricated slot gaps are not an economical solution for a product portfolio with a wide variety of variants, as is often the case in the area of low-voltage motors. Another application for medium and high voltage machines is the use of a still uncrosslinked, highly filled paste consisting of iron filler particles and chemical reactive resin (mixing ratio approx. 90 percent by weight iron filler, 10 percent by weight polymer matrix). The mass must be kneaded for several hours under active cooling to ensure homogenization of the particles in the matrix and then stored and transported in a cool place, as it is a one-component, reactive mass. The matrix component is, for example, an anhydrite-cured epoxy resin, which hardens when exposed to a higher temperature (150°C, several hours) to form a molding material that has sufficient mechanical strength and a glass transition temperature of over 140°C, thus meeting the requirements of medium voltage and high voltage machines for the insulation system and the peripherals. Due to the choice of matrix and iron filler composition as well as the high mechanical requirements for the final molding material and during application, additional additives such as talcum (as a lubricant) and polymer fibers (as reinforcement of the mass and thixotropy during processing) in the single-digit weight percentage range are necessary. The introduction of the material is done at room temperature either manually ("spackling") or by a (partially) automated bead application and subsequent pressing in using a special squeegee. The thermal hardening is then brought about by a hot air oven or by applying current to the windings. The object of the present invention is to propose an economical and low-energy possibility for slot filling, especially in low-voltage machines. According to the invention, this object is achieved by a method and a device according to the independent claims. Advantageous further developments of the invention emerge from the subclaims. The invention is based on the knowledge that low-voltage motors that have a high level of efficiency have only very low power losses, which manifest themselves in heating of the rotor and the stator, whereby a temperature of over 100 °C is almost impossible, particularly in the area of a possible slot closure. This allows a new perspective on the thermal stability of the insulation system and its periphery. In particular, the periphery (e.g. the cover slide) can be well below the thermal class F/H (155 °/180 °C, 20,000 h) otherwise required for the primary insulation system, without negatively affecting the service life or performance of the machine. Based on this development, the invention presents an alternative polymer solution for slot filling, which represents an economical and a