STATOR AND METHOD FOR PRODUCING A STATOR OF AN ELECTRIC MACHINE

Abstract

A method for producing a stator (20) of an electric machine is provided. The method includes providing a stator (20) with at least one stator slot (22) that is bounded by two stator teeth. The method proceeds by introducing electrical conductors (30) into the at least one stator slot (22). At least one conductor (30) has an expandable coating (25) applied partially to its surface. The method continues by activating the expandable coating (25) to bring about an expansion of the coating (25), as a result of which the conductors (30) are fixed within the stator slot (22).

Claims

1. A method for producing a stator of an electric machine, comprising: providing the stator with at least one stator slot that is bounded by two stator teeth; introducing electrical conductors into the at least one stator slot, with at least one of the conductors having an expandable coating applied partially to its surface; activating the expandable coating to bring about an expansion of the coating and thereby fixing the conductors within the stator slot.

2. The method of claim 1, wherein the step of activating the expandable coating is carried out by supplying heat.

3. The method of claim 1, wherein the step of activating the coating forms at least one continuous fluid connection running through the stator slot, said fluid connection being formed by regions of the surface of the at least one conductor that are not covered with the coating.

4. The method of claim 1, further comprising: providing the conductors; and applying the expandable coating partially to at least one of the conductors.

5. The method of claim 1, further comprising: providing the conductors; applying the expandable coating entirely to the surface of the conductor; and removing the expandable coating from selected regions of the conductor.

6. The method of claim 1, wherein the expandable coating applied partially to the surface of at least one conductor is structured in such a way that, between regions of the conductor that protrude from the stator after the conductors have been inserted into the stator slot, there is at least one continuous path that runs on an uncoated surface of the conductor.

7. The method of claim 1, wherein the partial coating is arranged in the form of a spiral on the surface of the at least one conductor.

8. The method of claim 1, wherein the partial coating is arranged in the form of plural layers that are separate from one another on the surface of the at least one conductor in such a way that, between regions of the conductor protruding from the stator after the conductors have been inserted into the stator slot, there are continuous paths that run on an uncoated surface of the conductor.

9. A stator for an electric machine, said stator comprising: at least one stator slot that is bounded by two stator teeth; and electrical conductors arranged within the at least one stator slot, wherein the conductors are fixed within the stator slot and a surface of at least one conductor arranged within the stator slot is covered partially with an expanded coating.

10. The stator of claim 9, further comprising: at least one fluid connection that runs through the at least one stator slot, the fluid connection being formed by regions of the surface of the at least one conductor that are not covered by the coating.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG. 1 shows a flow diagram in which one exemplary embodiment of the method according to the invention is illustrated.

[0031] FIGS. 2A and 2B show a simplified illustration of a stator produced using the method of the invention, before and after activation of the partial expandable coating.

[0032] FIGS. 3A and 3B show two exemplary conductors that may be used in the context of the method of the invention for formation of the winding of the stator.

DETAILED DESCRIPTION

[0033] One embodiment of the method of the invention is illustrated in FIG. 1. In a first step 10, the method comprises providing a conductor coil, for example a copper conductor coil, onto which the conductor has been wound. In this step, the coil is unwound for preparatory purposes.

[0034] Step 11 includes partial coating a part of the conductor strip that corresponds to the at least one conductor with the partial expandable coating.

[0035] Step 12 includes producing the required conductors by separating/severing the conductors from the conductor strip, it being possible here to provide the conductors in the correct length. If a plug-in coil is used, this step may also include the production of the so-called hairpins (hairpin-shaped conductors) by way of corresponding bending of straight conductor pieces.

[0036] Step 13 includes forming the winding of the stator by way of introduction/arrangement of the conductors in the slots of the laminated stator core.

[0037] Step 14 includes activating the partial expandable coating on the at least one conductor to expand the coating and thus fix the conductors within the stator slot.

[0038] Although the embodiment of the method outlined in FIG. 1 contains the specific steps for producing the conductors used for the construction of the winding of the stator, these steps are optional from the perspective of the invention, since suitably configured conductors may be acquired from a supplier, and therefore the production method may begin with the provision of a stator and the introduction of the prefabricated conductors into the stator slot. Consequently, the method according to the invention may begin essentially at step 13 of the embodiment illustrated in FIG. 1.

[0039] FIGS. 2A and 2B show a simplified schematic illustration of a stator 20 produced using the method of the invention, before (FIG. 2A) and after (FIG. 2B) activation of the partial expandable coating, respectively.

[0040] In FIG. 2A, partially coated and fully coated conductors have been introduced into a stator slot 22 of the laminated stator core 21. Each conductor comprises a conductor core 23, which may for example comprise copper, and an insulation layer 24. Furthermore, two of the three conductors have a partial, that is to say a partial or incomplete, coating 25, while one conductor is covered completely in full with the coating 25. The partially coated conductors are distinguished in that uncoated regions 26 are present on their surface. It should be emphasized that the configuration illustrated in FIG. 2A shows a greatly simplified scenario that is merely exemplary with regard to the number, design and arrangement of the partially and completely coated conductors. For example, practically all of the conductors used may have a partial expandable coating, and the coating patterns on each conductor may be identical or different.

[0041] The expandable layer 25 in FIG. 2A is in its non-activated, that is to say non-expanded form. It is therefore possible for the conductors to be introduced into the slot 22 without, or with low, frictional resistance. By contrast, FIG. 2B illustrates the state of the stator 20 after the expandable coating 25 has been activated. As a result of the activation, the expandable coating 25 has experienced a change in volume, such that the individual conductors are fixed within the slot 22. In this case, the uncoated regions 26 form flow channels which provide a connection between the end side and the bottom side of the stator 21 through the slot 22. The inlets to the flow channels on both sides may be, but do not have to be, uniquely assigned to a respective flow channel.

[0042] FIGS. 3A and 3B show two exemplary conductors 30 that may be used in the context of the method according to the invention to form the winding of the stator 20. As in FIG. 2A and 2B, each conductor 30 likewise comprises a conductor core 23 and an insulation layer 24. The conductor 30 shown in FIG. 3A has a segmented partial coating 25 with plural discrete layers of the coating material 25. Between the left and right ends of the conductor 30, a fluid can flow along paths formed by regions 26 that are not coated with the expandable material. The regions of the conductor 30 referred to here as ends may be understood to mean regions that are spaced apart from one another in a longitudinal direction of the conductor (30). Such an exemplary flow path is illustrated in FIG. 3A by the arrow 31.

[0043] FIG. 3B illustrates a further example of a structured partial coating 25 of a conductor 30 with the expandable material 25. In this example, the partial coating 25 is in the form of a line which forms a spiral staircase-like structure 32 around the conductor 30. The region 26 that is not coated with the expandable material correspondingly forms a coherent region, which is likewise arranged in a helical or spiral staircase-like manner around the conductor 30. This coherent region constitutes a continuous connection between the left and right ends of the conductor 30 and can consequently be used as a cooling fluid channel.