ELECTRIC MACHINE WITH FLEXIBLE ELECTRICAL CONDUCTORS AND SHAPING INSULATIONS

Abstract

The present invention relates to an electric machine (1) having a rotor (3) and a stator (2), wherein the stator (2) and/or the rotor (3) has an electrical plug-in winding (4), which comprises a plurality of rigid insulated electrical conductor elements (5); the conductor elements (5) are arranged in grooves of the stator or of the rotor and their conductor ends (17) project out of the grooves; the conductor ends of the conductor elements (5) are each connected to conductor ends of other conductor elements (5) in order to form the electrical plug-in winding (4); the conductor elements (5) have an electrically insulating insulation sheath (9); characterized in that each conductor element (5) has a multiplicity of flexible fibres (8), in particular of a conductor strand of flexible fibres (8), made of carbon nanotubes or graphene and in that the insulation sheath (9) surrounds the multiplicity of fibres (8) like a hose and is designed in such a way that it gives the electrical conductor element (5) a rigid form.

Claims

1. An electric machine (1) having a rotor (3) and a stator (2), wherein the stator (2) and/or the rotor (3) has an electrical plug-in winding (4), which comprises a plurality of rigid insulated electrical conductor elements (5), wherein the conductor elements (5) are arranged in grooves of the stator (2) or the rotor (3) and project out of the grooves with conductor ends (17), wherein the conductor ends (17) of the conductor elements (5) are each connected to conductor ends (17) of other conductor elements (5) to form the electrical plug-in winding (4), wherein the conductor elements (5) each have an electrically insulating insulation sheath (9), tubularly surrounding a multiplicity of flexible fibers (8), and wherein the insulation sheath (9) is configured to give the electrical conductor element (5) a rigid form.

2. The electric machine (1) as claimed in claim 1, characterized in that the insulation sheath (9) is thermally shrunk onto the multiplicity of flexible fibers (8).

3. The electric machine (1) as claimed in claim 1, characterized in that the insulation sheath (9) braces the multiplicity of flexible fibers (8) in the conductor bundle, in the insulation sheath (9) with a tensile force.

4. The electric machine (1) as claimed in claim 1, characterized in that the insulation sheath (9) is formed from a thermoplastic material.

5. The electric machine (1) as claimed in claim 1, characterized in that the insulation sheath (9) consists of an insulation material which has a negative coefficient of expansion.

6. The electric machine (1) as claimed in claim 1, characterized in that each conductor element (5) is designed configured in a U shape or I shape and has a quadrangular cross section.

7. The electric machine (1) as claimed in claim 1, characterized in that the flexible fibers (8) of each conductor element (5) project out of the respective insulation sheath (9) with the flexible fiber ends (18) at the two conductor ends (17) of the respective conductor element (5) in order to electrically connect the respective conductor element (5) to other conductor elements (5).

8. A method for producing substantially rigid insulated electrical conductor elements (5) for a plug-in winding (4) for a rotor (3) and/or a stator (2) of an electric machine (1), having the following steps: surrounding a bundle of flexible fibers (9) made of carbon nanotubes or graphene with a tubular insulation sheath (9) to form a conductor element (5), arranging the conductor element (5) in a shaping depression (14) of a shaping device (12), heating the conductor element (5) in the depression of the shaping device (12) by means of at least one heating element (15) to a temperature which effects thermal shrinking of the insulation sheath (9), and cooling the conductor element (5).

9. The method according to claim 8, wherein the electric machine (1) is an electric drive machine for an electrically driven vehicle, and wherein the conductor element (5) is heated to a temperature which effects a contraction of the insulation sheath (9).

10. An electric machine (1) having a rotor (3) and a stator (2), wherein the stator (2) and/or the rotor (3) has an electrical plug-in winding (4), which comprises a plurality of rigid insulated electrical conductor elements (5), wherein the conductor elements (5) are arranged in grooves of the stator (2) or the rotor (3) and project out of the grooves with conductor ends (17), wherein the conductor ends (17) of the conductor elements (5) are each connected to conductor ends (17) of other conductor elements (5) to form the electrical plug-in winding (4), wherein the conductor elements (5) each have an electrically insulating insulation sheath (9) tubularly surrounding a conductor bundle of flexible fibers (8) made of carbon nanotubes or graphene, and wherein the insulation sheath (9) is configured to give the electrical conductor element (5) a rigid form.

11. The electric machine (1) as claimed in claim 10, characterized in that the insulation sheath (9) is thermally shrunk onto the multiplicity of flexible fibers (8).

12. The electric machine (1) as claimed in claim 11, characterized in that the insulation sheath (9) braces the conductor bundle in the insulation sheath (9) with a tensile force.

13. The electric machine (1) as claimed in claim 12, characterized in that the insulation sheath (9) is formed from polyether ether ketone.

14. The electric machine (1) as claimed in claim 13, characterized in that the insulation sheath (9) consists of an insulation material which has a negative coefficient of expansion.

15. The electric machine (1) as claimed in claim 14, characterized in that each conductor element (5) is configured in a U shape or I shape and has a rectangular cross section.

16. The electric machine (1) as claimed in claim 15, characterized in that the conductor bundle of each conductor element (5) project out of the respective insulation sheath (9) with the flexible fiber ends (18) at the two conductor ends (17) of the respective conductor element (5) in order to electrically connect the respective conductor element (5) to other conductor elements (5).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Exemplary embodiments of the invention are described in detail below with reference to the accompanying drawing. In the drawing:

[0022] FIG. 1 shows a schematic view of an electric machine according to an exemplary embodiment of the invention;

[0023] FIG. 2 shows a schematic view of a stator of the electric machine according to the exemplary embodiment of the invention;

[0024] FIG. 3 shows a schematic partial view of the stator of the electric machine according to the exemplary embodiment of the invention;

[0025] FIG. 4 shows a schematic view of a section through an electrical conductor element of a plug-in winding of the stator of the electric machine according to the exemplary embodiment of the invention;

[0026] FIG. 4a shows a schematic view of an end region of the electrical conductor element of a plug-in winding of the stator of the electric machine according to the exemplary embodiment of the invention;

[0027] FIG. 5 shows a schematic view of a further electrical conductor element of the plug-in winding of the stator of the electric machine according to the exemplary embodiment of the invention; and

[0028] FIG. 6 shows a schematic view of a shaping device for carrying out a production method of the electrical conductor elements of the plug-in winding of the stator of the electric machine according to the exemplary embodiment of the invention.

DETAILED DESCRIPTION

[0029] FIG. 1 shows a schematic representation of an electric machine 1 according to an exemplary embodiment of the invention. The electric machine 1 has a rotor 3 and a stator 2. The stator 2 is arranged on a housing 2a, wherein a rotor shaft 3a, to which the rotor 3 is attached, is rotatably mounted on the housing 2a. The rotor 3 is therefore rotatable about a center axis 100, wherein the center axis 100 is also a center axis of the stator 2. The electric machine 1 is particularly advantageously a drive system for a vehicle, for example an automobile or a bicycle.

[0030] FIG. 2 shows a schematic representation of the stator 2 of the electric machine 1 according to the exemplary embodiment of the invention. The stator 2 has a stator base body 6, to which a plug-in winding 4 is attached 4. The plug-in winding 4 is composed of a multiplicity of individual rigid insulated electrical conductor elements 5. This is shown in FIG. 3. Therefore, in particular, a multiplicity of I-shaped conductor elements 5 and/or U-shaped conductor elements 5 is provided, wherein these conductor elements 5 are inserted into stator grooves 7 of the stator base body 6. Conductor ends 17 of the electrical conductor elements 5 project out of the stator grooves 7, wherein the conductor ends 17 of the conductor elements 5 are appropriately connected to conductor ends 17 of other conductor elements 5 in order to form the plug-in winding 4, in particular to realize three separate winding phases on the stator base body 6. The stator base body 6 is advantageously composed of a stack of multiple individual laminations, wherein FIG. 3 shows only one of these stator laminations for the sake of simplicity and for better clarity.

[0031] As a result of a plug-in winding 4 which is constructed in this way, it is achieved that high electric currents can flow through the electrical conductor elements 5. In particular, the individual conductor elements 5 have a larger cross section than conventional conductors. In particular, a rectangular cross section is present. A current-carrying capacity of the individual conductor elements 5 is thus increased, resulting in the electrical machine 1 having a high output power.

[0032] FIG. 4 shows a section through one of the insulated electrical conductor elements 5 which can be used to produce the plug-in winding 4. The electrical conductor element 5 is I-shaped in the exemplary embodiment shown in FIG. 2. FIG. 4A shows an end region of the conductor element 5.

[0033] The insulated electrical conductor element 5 comprises a multiplicity of flexible electrically conductive fibers 8, in particular of a conductor bundle of flexible fibers 8, made from carbon nanotubes (CNT). The flexible fibers 8 are arranged inside a sleeve-like or tubular and substantially rigid electrically insulating insulation sheath 9. The insulation sheath 9 is preferably formed from plastic, in particular from polyether ether ketone (PEEK).

[0034] Fiber ends 18 of the fibers 8 project out of the insulation sheath 9 at the conductor ends 17 of the conductor element 5 and are therefore not electrically insulated. These fiber ends 18 serve in particular for electrically connecting two connector elements 5 to produce the plug-in winding 4 as described above.

[0035] The flexible fibers 8 have a preferably textile behavior. Therefore the flexible fibers 8 can preferably be arranged with a high fill-density in the insulation sheath 9. The form of the conductor element 5 is therefore specified by the insulation sheath 9, since the rigid insulation sheath 9 gives the conductor element 5 a rigid form. The multiplicity of flexible fibers 8 moreover results in a high current-carrying capacity, whilst a low density and therefore a low weight of the conductor element 5 are realized through the use of carbon nanotubes. This enables the provision of an electric machine 1 with a high power density.

[0036] FIG. 5 shows a further exemplary embodiment of an insulated electrical conductor element 5 having a multiplicity of flexible fibers 8. In contrast to the exemplary embodiment shown in FIG. 4, the insulated electrical conductor element 5 according to FIG. 5 is U-shaped.

[0037] The U-shaped insulated electrical conductor element 5 comprises two limbs 10, which are connected by a transverse region 11. Apart from the shape, the construction of the exemplary embodiment of the conductor element 5 which is shown in FIG. 4 does not differ from the exemplary embodiment of the conductor element 5 which is shown in FIG. 5. Therefore, a sleeve-like or tubular insulation sheath 9, in which a plurality of flexible fibers 8 are arranged, is also shown in FIG. 5. The flexible fibers 8 therefore extend from one limb 10 to the other limb 10 via the transverse region 11 and project out of the insulation sheath 9 with their fiber ends 18 at conductor ends 17 of the limbs 10. The advantages of the electrical conductor element 5 according to the exemplary embodiment illustrated in FIG. 5 are the same as those of the exemplary embodiment of the electrical conductor element 5 which is illustrated in FIG. 4.

[0038] In both exemplary embodiments, the conductor ends 17 of the conductor elements 15 can be electrically contacted in order to electrically connect the respective conductor element 5 to other components. In particular, the conductor elements 5 can be electrically contacted by one another to produce the plug-in winding 4. The conductor elements 5 can therefore be used in particular in the manner of conventional parts of a plug-in winding.

[0039] FIG. 6 shows a shaping device 12 for producing the above-described insulated electrical conductor elements 5 according to an inventive method. The shaping device 12, shown by way of example, serves in particular for producing the insulated electrical conductor element 5 shown in FIG. 5.

[0040] The shaping device 12 has a base body 13 and a depression 14 formed in the base body 13. The depression 14 extends in a U shape and has, in particular, a quadrangular or rectangular cross-sectional form. Another course of the depression 14 is furthermore also conceivable, in particular an I-shaped path for producing the insulated electrical conductor element 5 shown in FIG. 4.

[0041] The shaping device 12 comprises a multiplicity of heating elements 15, which are fastened to the base body 13 and which are distributed around the depression 14. The heating elements 15 preferably have an elongated form, which extends along the depression 14. However, it is also conceivable to arrange a multiplicity of punctiform heating elements 15 along the depression 14.

[0042] The heating elements 15 are preferably designed as thermoelements. Alternatively, however, they can also be designed as a heating wire, for example. The heating elements 15 are preferably screwed into the base body 13. However, a plug-in connection between the heating elements 15 and the base body 13 is also conceivable.

[0043] To produce the insulated electrical conductor elements 5, a multiplicity of electrically conductive flexible fibers 8 is firstly guided through an insulation sheath 9. The insulation sheath 9 is sleeve-like or tubular with an angular or circular cross-sectional form and, at this point, does not have to have the final form of the conductor element 5. The insulation sheath 9, with the flexible fibers 8 arranged therein, is subsequently arranged in the depression 14 formed in the base body 13 of the shaping device 12.

[0044] After the insulation sheath 9 and the flexible fibers 8 have been arranged in the depression 14, the insulation sheath 9 is heated by the heating elements 15.

[0045] The insulation sheath 9 is preferably a thermoplastic material, in particular polyether ether ketone (PEEK). In this case, during the production of the conductor element 5, the insulation sheath 9 is heated to the thermoplastic range. The thermoplastic range is the temperature range in which the heated insulation sheath 9 remains plastically deformed, i.e. it does not assume its original form again.

[0046] The heat supply via the heating elements 15 is subsequently interrupted so that the insulation sheath 9 can preferably harden. The hardening can take place passively, i.e. the cooling of the insulation sheath 9 is effected merely by interrupting the heat supply and therefore without additional measures. However, the hardening can also be performed actively, for example using additional cooling elements and/or using means which effect the forced convection. In both cases, the insulation sheath 9 preferably remains in the depression 14 during the hardening in order to enable the conductor element 5 to form completely. This results in a high fill-density of the conductor element 5.

[0047] The conductor element 5, which substantially maintains the form of the depression 14 can subsequently be removed from the depression 14 in one piece. The conductor element 5 now has the fixed form created by the method.

[0048] The insulation sheath 9 is preferably shrinkable tubing and/or is manufactured from a material which has a negative coefficient of thermal expansion. The insulation sheath 9 is therefore preferably thermally shrunk onto the multiplicity of flexible fibers 8 and preferably designed to apply a tensile force to the flexible fibers 8, in particular the conductor bundle, located inside the insulation sheath during the heating by means of the heating elements 15. Tight packing of the fibers 8 and therefore a high fill-density of the conductor element 5 are therefore realized. Together with the low density of carbon nanotubes, it is therefore possible to achieve a high current-carrying capacity of the plug-in winding 4 formed by the conductor elements 5 along with a low weight. The electric machine 1 therefore has a high power density.