COMPRESSED STRAND, STATOR OR ROTOR OF AN ELECTRICAL MACHINE, AND ELECTRICAL MACHINE

Abstract

The present invention relates to a compressed strand comprising a wire pack consisting of at least two wires, wherein at least one head end of the compressed strand, preferably both head ends, has/have a contact-making section and a heat-exchange section, and to a stator or rotor of an electric motor, wherein the rotor or stator, respectively, is equipped with at least one compressed strand according to at least one of the preceding claims, and to an electric motor, comprising a stator and a rotor, characterized by a stator and/or rotor according to at least one of the preceding claims.

Claims

1. Compressed strand, comprising a wire pack of at least two wires for conducting electric current, wherein at least one head end of the compressed strand comprises an electric contact-making section and a heat-exchange section.

2. Compressed strand according to claim 1, wherein the wire pack, are surrounded with an electric insulation.

3. Compressed strand according to claim 1, wherein the contact-making section is formed of a sleeve surrounding the at least two wires at the end side, or of a welding of the at least two wires at the end side.

4. Compressed strand according to claim 1, wherein the heat-exchange section is embodied as a wire bundle.

5. Compressed strand according to claim 1, wherein the wires in the heat-exchange section are untwisted and/or spliced, respectively, in sections.

6. Compressed strand according to claim 1, wherein the wires are not insulated in the heat-exchange section.

7. Compressed strand according to claim 1, wherein the heat-exchange section is embodied as an extension of the compressed strand over the contact-making region (11).

8. Compressed strand according to claim 1, wherein the heat-exchange section is embodied in a form suited for guiding and/or swirling a cooling medium.

9. Stator or rotor of an electrical machine, in particular an electric motor and/or an electric generator, wherein the rotor or stator is equipped with at least one compressed strand according to claim 1.

10. Stator or rotor according to claim 9, wherein at least two compressed strands are connected to each other via the contact-making section.

11. Stator or rotor according to claim 1, wherein the at least two compressed strands are connected to each other by means of welding or by means of an interconnection web.

12. Electrical machine, in particular electric motor and/or electric generator, comprising a stator and a rotor, according to claim 9.

13. Electrical machine according to claim 12, wherein the electric motor is equipped with a cooling means for cooling the at least one heat-exchange section.

14. Electrical machine according to claim 12, wherein a fluid, is admitted to the cooling means.

15. Compressed strand according to claim 2, wherein the wires of the wire pack are surrounded with an electric insulation.

16. Compressed strand according to claim 3, wherein the sleeve is a metal sleeve.

17. Compressed strand according to claim 4, wherein the wire bundle is formed of the wires of the compressed strand.

18. Electrical machine according to claim 12, wherein an oil is admitted to the cooling means.

Description

[0043] A compressed strand F according to the invention essentially comprises a first head end 1 as well as a second head end 2. A wire pack 3 is arranged between these head ends 1, 2.

[0044] The wire pack 3 consists of a number of wires 31, at least, however, two wires, which are usually twisted and are preferably surrounded by a main insulation layer 32 as a wire pack. The compressed strand is moreover compacted and preferably has a rectangular or trapezoidal cross-sectional area. The wires 31, preferably of copper or a copper alloy, as such can also be individually equipped with an insulation 311, or else they may not be insulated or partially stripped, in particular at the head ends.

[0045] According to the invention, at least one head end 1 or 2 of the compressed strand, preferably both head ends 1 and 2, comprise a contact-making section 11 and a heat-exchange section 12.

[0046] In the region of the contact-making section 11, the wire sections located there are electrically and mechanically connected to each other, which can be done by means of sleeves of metal or else by welding the individual wires 31 in this region.

[0047] The heat-exchange section 12 is preferably embodied as a wire bundle, in particular, the wire bundle is formed of the individual wires 31 of the compressed strand, wherein the individual wires are preferably un-twisted and/or spliced in sections in the heat-exchange section.

[0048] The individual wires 31 are preferably stripped in the heat-exchange section 12, in particular not only of the common main insulation 32, but also of the optionally provided individual wire insulation 311. The additional cooling surface formed by the heat-exchange section 12 can be embodied as an extension of the compressed strand F over the contact-making region 11. In this case, it is not used for carrying current but primarily has the function of a thermal bridge. The region can be embodied in different cross-sectional shapes, in particular for guiding and/or swirling the cooling medium. As a result, a cooling surface is suggested which is increased compared to the cross-section of the compressed strand and which is formed by individual wire surfaces.

[0049] The heat-exchange section 12 can be arranged, with respect to the wire pack 3, between the wire pack 3 and the contact-making section 11, or next to the contact-making section 11, that means at the end side of the compressed strand. In the first case, a sequence of wire pack 3, heat-exchange section 12, contact-making section 11 is formed, while in the second case, a sequence of wire pack 3, contact-making section 11, and heat-exchange section 12 results in the longitudinal direction of the compressed strand. The heat-exchange section 12 and the contact-making section 11 are normally separate regions.

[0050] The provision of a heat-exchange section 12 has numerous advantages.

[0051] For example, the cooling effect is high due to the increased cooling surface. This can be illustrated with reference to a sample calculation. A normal compressed strand head creates a heat-exchange surface with about 3*6*10 mm=150 mm.sup.2. With 15 wires having a diameter of 1 mm.sup.2, a heat-exchange section 12 according to the invention creates a heat-exchange surface of approximately (d*pi)*h=1*3.14*10=314 mm.sup.2.

[0052] The heat-exchange section 12 offers an additional impact area for a cooling medium flowing therethrough. The heat transfer can thus be locally increased.

[0053] The heat-exchange section 12 can form fluid flow guide elements (not shown) which take care of an additional swirling of the cooling flow and thus increase the heat transfer altogether since less quasi-static boundary layers are formed.

[0054] At least one of the above-described compressed strands F can be installed in the stator S and/or rotor R of an electrical machine, in particular an electric motor. As an electrical machine, an electric motor and/or an electric generator, for example also within one aggregate, is possible. To achieve a heat-exchange surface as large as possible, each one or a large number of the compressed strands used is/are preferably compressed strands F according to the invention with the corresponding heat-exchange sections 12.

[0055] In this context, at least two compressed strands F can be connected to each other via their contact-making section 11 at least electrically, preferably electrically and mechanically. This can be achieved, for example, by a welding 6 of the contact-making regions 11 as well as by a connection of the contact-making regions by means of an interconnection web 5. The connection of the interconnection web and the compressed strand can also be designed as a welding. The invention can equally be employed for direct interconnections and for indirect interconnections with interconnection webs.

[0056] An electrical machine according to the invention, in particular an electric motor, in turn comprises a rotor R and/or stator S according to the invention with at least one compressed strand F according to the invention. Preferably, such an electrical machine is equipped with a cooling means 4 for cooling the heat-exchange sections. The cooling means 4 can comprise, for example, a cooling cap which is arranged around the compressed strand ends, but in particular the heat-exchange sections 12. It is preferably provided for the cooling means 4 to be embodied for cooling by means of a fluid, in particular an oil. To this end, an oil supply can be incorporated in the cooling cap.

[0057] To the figures in detail:

[0058] In FIG. 1, a compressed strand according to prior art only with contact-making regions 11 in the form of sleeves is shown. Between the contact-making regions 11, the wire pack 3 is arranged. In the cross-section, the individual wires 31 can be seen.

[0059] In FIG. 2, a cross-section of an electrical machine according to the invention, in particular an electric motor, comprising the rotor R and stator S is shown (upper part) with an axis X. Furthermore, one can see the essential elements of the cooling means, in particular the cooling cap 4 and the oil supply (without reference numeral).

[0060] In FIG. 3, the stator S of the electrical machine, in particular the electric motor, is depicted in a cross-sectional representation. The flow direction of a cooling medium, for example oil, as well as, by way of example, two interconnection webs 5 are indicated. Two compressed strands F according to the invention are provided per slot.

[0061] In FIGS. 4 to 7, different embodiments of compressed strands F according to the invention or their head ends 1, respectively, are represented. Furthermore, individual manufacturing steps are schematically indicated.

[0062] In FIG. 4a, for example, a compressed strand blank with insulated individual wire ends 31 and 311 as well as its main insulation 32 are represented. In FIG. 4b, the heat-exchange section 12 and the contact-making section 11 in the form of a sleeve can be seen. The sleeve is applied, for example, by means of electrode welding. The heat-exchange section 12 is embodied, for example, as a protruding projection. Splicing is done, for example, automatically when the sleeve is applied or pressed, respectively.

[0063] In FIG. 5b, a possible intermediate step in the manufacture of a compressed strand according to the invention is represented, in particular the stripping of the insulation varnish 311 of the individual wires 31 for a better heat transfer.

[0064] In FIG. 6b, a triangular design of the heat-exchange section end is represented.

[0065] In FIG. 7, an example of an end-sided contact-making region and a heat-exchange section 12 arranged between the wire pack 3 and the contact-making region 11 is represented.

[0066] In FIG. 7b, a partial stripping of the individual wires 31 in the head region of the compressed strand F is represented, this concerning both the contact-making section and the heat-exchange section. In FIG. 7c, the creation of a contact-making section 11 by applying a sleeve at the end of the stripped individual wires 31 is represented.

[0067] The untwisting, represented in FIG. 7d, leads to a bloating of a heat-exchange section 12 between the wire pack 3 and the contact-making region 11.

[0068] In FIG. 8a, a welding of a compressed strand 3, in particular the contact-making region 11, with an interconnection web 5 is represented. In FIG. 8a, an exemplary projection of the heat-exchange section 12 is represented.

[0069] FIGS. 9a and 9b, respectively, schematically show how the cooling medium flows through the heat-exchange section 12. In the process, the cooling medium flows through the complete wire bundle, and not only through an outer contour.

[0070] In FIG. 10, an unwinding of a stator S or stator wire pack B, respectively, according to the invention is shown in sections, wherein the compressed strands are bent towards each other in pairs. The contact regions 11 of the compressed strands F are directly welded to each other, that means they include a welding 6. The winding head is enclosed by a cooling cap, and an oil flows therethrough. By the heat-exchange sections 12 embodied as a projection, the heat transfer of the compressed strands F otherwise surrounded by a main insulation can be improved.

[0071] Features and details described in connection with a method naturally also apply in connection with the device according to the invention, and vice versa, so that with respect to the disclosure, mutual reference is made, and can be made, to the individual aspects of the invention.