WO2018188945A1

WO2018188945A1 - Stator for an electrical machine, and method for producing a stator of an electrical machine

Info

Publication number: WO2018188945A1
Application number: PCT/EP2018/057794
Authority: WO
Inventors: Fabian Lange; Patrick PRIEBE
Original assignee: Robert Bosch Gmbh
Priority date: 2017-04-11
Filing date: 2018-03-27
Publication date: 2018-10-18
Also published as: DE102017206219A1

Abstract

The invention relates to a stator (10) for an electrical machine, comprising conductor elements (20, 21) inserted in the stator (10), ends (48) of the conductor elements (20, 21) projecting out of the stator (10) being partially, particularly in pairs, welded to each other. Said stator is characterised by a bridging means (60) for increasing the thickness of an electrical insulation material (50) on the ends (48) of the conductor elements (20, 21), the bridging means (60) being arranged on front sides of the ends (48) of the conductor elements (20, 21), at a determined distance from the respective ends (48) of the conductor elements (20, 21) by means of a gap, the gap between the ends (48) of the conductor elements (20, 21) and the bridging means (60) being designed so as to be bridged by the insulation material (50), the bridging means (60) comprising a part of the conductor element (20, 21) or a separate element.

Description

Description title

Stator for an electric machine and method for manufacturing a stator of an electric machine

Field of the invention

The invention relates to a stator for an electrical machine and to a method for producing a stator of an electrical machine.

State of the art

In stators for electrical machines in plug-in technology, the inserted and covered with an electrically insulating paint conductor elements must be connected together to produce the overall winding. The conductor elements are hereby usually partly, in particular in pairs, welded together, e.g. by laser welding. For welding, the ends of the conductor elements usually have to be freed of the varnish, so that during welding no inclusions are formed in the weld due to outgassing of the varnish. After welding, the welded together ends of the conductor elements are thus free of paint. Particularly in the automotive sector, high demands are placed on the power density of the electrical machine or the stator. Therefore, to ensure the insulation strength or dielectric strength, an insulating material must be applied to the lacquer-free ends of the conductor elements. This is especially true when the electric machine is to be operated with the stator in an oil environment.

The problem with the application of insulation material to the lacquer-free ends of the conductor elements after welding is that they often have sharp-edged areas. When applying the insulation material in the region of the ends of the

A high capillary pressure on the liquid / liquefied insulation material acts locally on the conductor elements or the sharp edges, which "pushes" the insulation material away from the edges, resulting in a smaller thickness of the insulation material in the area of the insulation material Edges or the ends of the conductor elements. Thus, the insulating material often has a thinner compared to the other areas of the conductor element thickness. With a smaller thickness of the insulating material, the insulation strength of the conductor element decreases. Increasing the thickness of the insulating material over the entire area of the ends of the conductor elements which is freed of lacquer, in order to achieve a predetermined dielectric strength or dielectric strength also in the region of the edges or ends of the conductor element, leads to an increased use of insulating material and thus to an increased level Costs.

Disclosure of the invention

Advantages of the invention

Embodiments of the present invention may advantageously make it possible to provide a stator in which insulating material is uniformly present on ends of the conductor elements, or insulation material on ends of the conductor elements

apply evenly.

According to a first aspect of the invention, a stator for an electrical machine is proposed comprising conductor elements inserted into the stator, wherein ends of the conductor elements protruding from the stator are partially, in particular in pairs, welded together, characterized by a bridge means for increasing a thickness of an electrical insulation material the ends of the conductor members, the bridging means being disposed at end faces of the ends of the conductor members spaced apart a predetermined distance from the respective ends of the conductor members, the gap between the ends of the conductor members and the bridging means being bridged by the insulating material to be, wherein the bridging means comprises a part of the conductor element or a separate element.

An advantage of this is that usually the insulation material on the ends of the

Conductor elements is arranged uniformly or with substantially the same thickness. This also typically applies if the edges of the ends of the conductor elements have low radii or are sharp-edged. As a result, material is generally saved. This usually reduces costs. In addition, the stator is typically designed to save space and space. The stator can also be operated in an oil environment usually. According to a second aspect of the invention, a method is proposed for producing a stator of an electrical machine, the method comprising the following steps: providing non-interconnected conductor elements inserted into the stator, wherein the ends protruding from at least the stator

Ladder elements are painted with a lacquer; Removing the paint from each at least a portion of the projecting from the stator ends of the conductor elements; Welding, in particular laser welding, of the parts freed of the paint from in each case two or more directly mutually adjacent conductor elements for the electrical connection of the two or more directly mutually adjacent conductor elements; Applying a liquid / liquefied insulating material for electrical insulation to the previously unpainted ends of the conductor elements while each bridging means is at a distance from the welded ends of the conductor elements such that the liquid / liquefied insulating material bonds between the respective ends welded together the conductor elements and the bridge means forms; and curing the insulation material.

The advantage of this is that the insulating material is typically applied evenly or with substantially the same thickness to the ends of the conductor elements. This usually takes place even when the ends of the conductor elements sharp edges or

Have edges with small radii. In addition, by this method usually a stator can be produced, which requires very little insulation material with high insulation strength and dielectric strength. The insulating material encloses respective ends of the conductor elements, wherein the ends enclosed by the respective insulation material are welded together. In each pair welded together ends of conductor elements, the insulating material thus encloses a pair of welded together ends of

Conductor elements.

Ideas for embodiments of the present invention may be considered, inter alia, as being based on the thoughts and findings described below.

According to one embodiment, the gap is equal to or less than one half of a diameter of the respective end of the conductor element. This is usually the Insulation material arranged evenly on the ends of the conductor elements. In addition, this typically typically ensures that the insulation material bridges the gap. According to one embodiment, the bridging means is part of a ring, which is arranged in the axial direction of the stator above the respective ends of the conductor elements. As a result, the bridging means can generally be embodied in a technically particularly simple and cost-effective manner. This usually reduces the manufacturing cost of the stator. According to one embodiment, the insulating material of the respective welded ends of the conductor elements at a distance from the insulating material of the immediately adjacent welded together ends of the conductor elements. One advantage of this is that typically there are no insulating material bridges between the insulating materials of immediately adjacent ends of the conductor elements. By insulating material bridges, the electrical insulation between non-welded ends of conductor elements could be lowered. Thus, typically, the lack of insulation material bridges between insulating materials of immediately adjacent ends of the conductor elements increases the insulation strength of the stator.

According to one embodiment, the ends of the conductor elements each have one or more sharp edges. One advantage of this is that the stator, in particular the conductor elements, is usually technically particularly easy to produce. This typically further reduces manufacturing costs.

According to one embodiment, the bridge means is in an imaginary direct extension of the ends of the conductor elements. The advantage of this is that the bridge of insulating material, which bridges the gap, typically consists of very little material or requires very little material. This generally reduces costs further.

According to one embodiment, the side of the additional element or of the additional elements facing the ends of the conductor elements has a surface which attracts the liquid insulating material. As a result, the formation of the bridge or bridges of insulation material over the gap is usually technical simplified. In addition, as a result, the insulating material bridge typically requires very little material.

According to one embodiment of the method, the insulation material is applied such that the insulation material of the respective welded ends of the conductor elements after applying and curing of the insulating material further comprises a distance to the insulating material of the immediately adjacent welded together ends of the conductor elements. This will make the

Isolationsmaterialbrücken between the insulating materials of immediately adjacent to each other ends of the conductor elements usually prevented. By

Insulation material bridges could be the electrical insulation between not welded together ends of conductor elements are lowered. Thus, in general, by preventing insulating material bridges between insulating materials from immediately adjacent ends of the conductor members, the insulation strength of the manufactured stator increases.

According to one embodiment of the method, during the application of the liquid / liquefied insulating material, the bridging means is at a distance from the ends of the conductor elements which are welded together and which is equal to or less than one half of a diameter of the respective end of the conductor element. As a result, the insulating material is applied even more uniformly on the ends of the conductor elements usually. In addition, this typically typically ensures that the insulation material bridges the gap. It should be understood that some of the possible features and advantages of the invention are described herein with respect to different embodiments of the stator. A person skilled in the art will recognize that the features can be suitably combined, adapted or replaced in order to arrive at further embodiments of the invention.

Brief description of the drawings

Hereinafter, embodiments of the invention will be described with reference to the accompanying drawings, wherein neither the drawings nor the

Description are to be construed as limiting the invention. Fig. 1 shows a perspective view of an embodiment of the stator;

Fig. 2 is a detailed perspective view of a portion of the stator of Fig. 1;

FIG. 3 shows a schematic cross-sectional view of a pair of ends of FIG

Ladder elements with bridge means; and

FIG. 4 shows another schematic cross-sectional view of a pair of ends of FIG

Ladder elements with bridge means.

The figures are only schematic and not to scale. Like reference numerals designate the same or equivalent features in the figures. Embodiments of the invention

Fig. 1 shows a perspective view of an embodiment of the stator 10. Fig. 2 shows a detailed perspective view of a portion of the stator 10 of Fig. 1. The stator 10 is formed for an electric machine. The stator 10 is designed in particular for a vehicle. The stator 10 is formed in plug-in technology. The electrical conductor elements 20, 21 are inserted into the stator 10. Ends 48 of the electrical

Conductor elements 20, 21 project out of the stator 10 upwards. The electrical conductors are uniformly spaced from one another along the circumference of the stator 10. On the bottom are also ends 48 of the conductor elements 20, 21 out of the stator 10 out. This is not shown in the drawings.

The conductor elements 20, 21 have at their ends 48 sharp edges 70, 75. These are due to the separation process (e.g., shearing of the conductor element 20, 21). The edges 70, 75 thus have small edge radii. The capillary pressure on a liquid or

Liquefied insulation material 50 in the edge area is calculated as follows:

in which σ the surface tension of the liquid insulating material 50, and

r is the edge radius. Thus, the capillary pressure increases sharply for decreasing edge radii. The electrical conductors are provided with a lacquer for electrically insulating the conductor elements 20, 21. The paint is not shown in the drawings.

The ends 48 of the conductor elements 20, 21 or areas thereof are freed from the paint. The ends 48 of the conductor elements 20, 21 comprise at least the end edges 70, 75 of the respective conductor element 20, 21 and a portion of the conductor element 20, 21 immediately adjacent the end edges 70, 75. The ends 48 of the conductor elements 20, 21 may, but need not, the complete projecting from the stator 10 part of the conductor elements 20, 21 each comprise. The ends 48 of the conductor elements 20, 21 are welded together in pairs. It is also conceivable that three or more than three ends 48 of conductor elements 20, 21 are each welded together. It is also spoken by pairs 40-45 of ends 48 of conductor elements 20, 21 welded together. By this term, however, more than two ends 48 of conductor elements 20, 21, e.g. three or four ends of conductor elements 20, 21, which are welded together comprises.

The welding may in particular include or be a laser welding.

After welding, the ends 48 of the conductor elements 20, 21 continue to be without lacquer or without electrical insulation.

It is a liquid or liquefied insulating material 50 for electrically insulating the welded together ends 48 of the conductor elements 20, 21 and the pairs 40-45 of ends 48 of the conductor elements 20, 21 welded together with respect to the

Environment on the ends 48 of the conductor elements 20, 21 applied. The insulation material 50 is applied in particular to the ends 48 of the conductor elements 20, 21 in such a way that all areas of the conductor elements 20, 21 or the ends 48 of the conductor elements 20, 21 previously freed of lacquer are provided with insulation material 50, so that the respective entire Conductor element 20, 21 is electrically isolated from the environment. The Insulation material 50 thus encloses respective ends 48 of conductor elements 20, 21, which are welded together.

During the application of the insulating material 50, a bridging means 60 is arranged in the vicinity of the ends 48 of the conductor elements 20, 21. Between the ends 48 and end edges 70, 75 of the respective conductor elements 20, 21 and the pairs 40-45 of ends 48 of the conductor elements 20, 21 and the bridge means 60, a gap or a distance is arranged. The distance or gap may be equal to or less than one half of a

Diameter of the respective end 48 of the conductor element 20, 21 be.

The gap is selected such that upon application of the insulating material 50, the liquid or liquefied insulating material 50 forms a bridge between the respective end 48 of the conductor element 20, 21 and the bridge means 60. The bridging means 60 may e.g. comprise a ring or be a ring. The ring may be formed of a plastic. The ring may in particular be made of a low-cost material. The material of the bridge means 60 is electrically non-conductive.

Due to the surface tension of the insulating material 50 thus the gap or

Distance between the pairs 40-45 of ends 48 of the conductor elements 20, 21 and the bridge means 60 bridged.

Instead of a ring, a plurality of individual bridge means 60 are conceivable which are each arranged at a distance from the ends 48 of the conductor elements 20, 21. The insulating material 50 forms a bridge between the respective ends 48 of FIG

Conductor elements 20, 21 or the respective pairs 40-45 of ends 48 of the conductor elements 20, 21 and the bridge means 60. This results in a uniform thickness of the applied insulating material 50 in the areas of the conductor elements 20, 21, of the ends 48 and end edges 70, 75 are spaced, and in the end regions or at the ends 48 / end edges 70, 75 of the conductor elements 20, 21 achieved. The capillary pressure of the liquid insulating material 50 at the ends 48 of the conductor members 20, 21 is thus similar or equal to the capillary pressure of the liquid insulating material 50 spaced from the ends 48 of the conductor members 20, 21 and the end edges 70, respectively. 75 of the ends 48 of the conductor elements 20, 21 is. After the application of the insulating material 50, the insulating material 50 is cured. This can be done for example by light and / or heat.

The bridge means 60 usually remains on the stator 10th

In Fig. 2, the insulating material 50 is around some of the pairs 40-45 of each other

welded ends 48 of the conductor elements 20, 21 shown in section (in particular the second, third and fourth pair 40-45 of ends 48 of the conductor elements 20, 21 from the left in Fig. 2).

The insulating material 50, each enclosing a first pair 40 of ends 48 of the conductor elements 20, 21, is spaced apart from the insulating material 50 which has a second pair 41 of ends immediately adjacent to the first pair 40 of ends 48 of the conductor elements 20, 21 48 of the conductor elements 20, 21 encloses. Thus, there are no direct bridges between the respective insulating materials 50. However, the insulating materials 50 are shown in FIG. 1 and FIG

Bridge means 60 indirectly connected.

The ring may have grooves. The ends 48 of the conductor elements 20, 21 are partially disposed in the grooves but spaced from the ring. The insulating material 50 closes this distance between the ends 48 of the conductor elements 20, 21 and the ring.

The absence of bridges between the insulating materials 50 of the respective pairs 40-45 of ends 48 of the conductor elements 20, 21 increases the dielectric strength of the stator 10 because no electrical current can flow over such bridges.

In the drawings, the bridging means 60 is an additional element to the stator 10 with conductor elements 20, 21. However, it is also conceivable that the bridge means 60 is a part or an area of the conductor element 20, 21 or another part of the stator 10. Again, the gap or distance by means of the insulating material 50 is bridged. The ends 48 of the conductor element 20, 21 may be bent accordingly, so that in the imaginary

Extension of the ends 48 of the conductor element 20, 21 is a part or area of the

Conductor element 20, 21 is located. Electrical connection elements or conductor elements 20, 21 for electrically connecting the stator 10 are not shown in FIG. 1 or in FIG. 2.

3 shows a schematic cross-sectional view of a pair 40-45 of ends 48 of conductor elements 20, 21 with bridge means 60. FIG. 4 shows another schematic cross-sectional view of a pair 40-45 of ends 48 of conductor elements 20, 21 with bridge means 60.

In Fig. 3 and Fig. 4 can be clearly seen how by the presence of a

Bridge means 60, a gap between the end edges 70, 75 of the ends 48 of

Conductor elements 20, 21 and the bridge means 60 is overcome. In addition, it can be clearly seen that the thickness of the insulation material 50 at the ends 48 of the conductor elements 20, 21 and at the other regions of the conductor element 20, 21 which have been freed of lacquer is similar or essentially the same.

In Fig. 3, an additional element as a bridge means 60 is present. In Fig. 4, the conductor element 20, 21 or a part thereof itself is the bridge means 60. Here, the end 48 of the conductor element 20, 21 and the ends 48 of the conductor elements 20, 21 bent accordingly, so that in the direct imaginary extension the ends 48 of the conductor elements 20, 21 a part of the respective conductor element 20, 21 itself is present.

The ring or the bridging means can also act as spacers to a cover of the stator or the electric machine. Finally, it should be noted that terms such as "comprising," "comprising," etc., do not exclude other elements or steps, and terms such as "a" or "an" do not exclude a multitude. Reference signs in the claims are not to be considered as limiting.

Claims

claims

Stator (10) for an electrical machine comprising in the stator (10) inserted conductor elements (20, 21), wherein from the stator (10) protruding ends (48) of the conductor elements (20, 21) partially, in particular in pairs, are welded together .

marked by

a bridge means (60) for increasing a thickness of an electrical

Insulating material (50) at the ends (48) of the conductor elements (20, 21),

wherein the bridging means (60) at end faces of the ends (48) of the conductor elements (20,

21) is spaced from the respective ends (48) of the conductor elements (20, 21) by a gap at a predetermined distance,

the gap between the ends (48) of the conductor elements (20, 21) and the

Bridge means (60) is adapted to be bridged by the insulating material (50), wherein the bridging means (60) comprises a part of the conductor element (20, 21) or a separate element.

The stator (10) of claim 1, wherein

the gap is equal to or less than one half of a diameter of the respective end (48) of the conductor element (20, 21).

A stator (10) according to claim 1 or 2, wherein

the bridge means (60) is part of a ring which is arranged in the axial direction of the stator (10) above the respective ends (48) of the conductor elements (20, 21).

Stator (10) according to one of the preceding claims, wherein

the insulating material (50) of the respective welded ends (48) of

Conductor elements (20, 21) at a distance from the insulating material (50) of the immediately adjacent welded together ends (48) of the conductor elements (20, 21). Stator (10) according to one of the preceding claims, wherein the ends (48) of the conductor elements (20, 21) each have one or more sharp

End edges (70, 75) have.

Stator (10) according to one of the preceding claims, wherein

the bridge means (60) is in an imaginary direct extension of the ends (48) of the conductor elements (20, 21).

Stator (10) according to one of the preceding claims, wherein

the side of the additional element or elements facing the ends (48) of the conductor elements has a surface that attracts the liquid insulating material (50).

Method for producing a stator (10) of an electrical machine,

the method comprising the following steps:

Providing non-interconnected conductor elements (20, 21) inserted into the stator (10), wherein ends (48) of the conductor elements (20, 21) projecting from at least the stator (10) are lacquered with a lacquer;

Removing the paint from at least part of the ends (48) of the conductor elements (20, 21) protruding from the stator (10);

Welding, in particular laser welding, of the parts freed of the paint from in each case two or more conductor elements (20, 21) immediately adjacent to one another for the electrical connection of the two or more directly adjacent conductor elements (20, 21);

Applying a liquid / liquefied insulating material (50) for electrical insulation on the previously lacquer - free ends (48) of the conductor elements (20, 21) while each bridging means (60) at such a distance to the mutually welded ends (48) of Conductor elements (20, 21) is that the liquid / liquefied insulating material (50) is a connection between the respective welded together ends (48) of the conductor elements (20, 21) and the

Bridge means (60) forms; and

Curing the insulation material (50).

The method of claim 8, wherein

the insulation material (50) is applied in such a way that the insulation material (50) the respective mutually welded ends (48) of the conductor elements (20, 21) after application and curing of the insulating material (50) further spaced from the insulating material (50) of the immediately adjacent welded together ends (48) of the conductor elements (20, 21) having.

10. The method of claim 8 or 9, wherein

the bridging means (60) is at a distance from the welded-together ends (48) of the conductor elements (20, 21) during the application of the liquid / liquefied insulating material (50), which is equal to or less than one half of a diameter of the respective end (50). 48) of the conductor element (20, 21).