STATOR FOR AN ELECTRICAL MACHINE AND METHOD FOR PRODUCING SAID STATOR

Abstract

A stator for an electrical machine, the stator having a yoke with longitudinal grooves, which extend along an inner peripheral edge parallel to a longitudinal axis of the yoke and are separated by stator teeth, wherein compressed strands are inserted into the longitudinal grooves, which strands each consist of individual wires, wherein respective ends of the strands exit the grooves at a yoke head and protrude from the yoke, while extending parallel to the axis, wherein the wires of each strand are electrically conductively connected at ends of the strand, and a first end of a first strand, which protrudes from one yoke head, is electrically conductively joined to a second end of a second strand, which protrudes from the one yoke head and comes from another groove, by a separate electrically conductive connecting element to form an electrical winding, the first end and the second end mechanically not touching.

Claims

1. A stator for an electrical machine, the stator comprising: a stator yoke that has longitudinal grooves, which extend along an inner peripheral edge of the stator yoke, parallel to a longitudinal axis LA of the stator yoke and each of which is separated by stator teeth (102); and one or more compressed strands inserted into the longitudinal grooves, the compressed strands each consist of a plurality of individual wires, which are each electrically insulated, wherein respective ends of the compressed strands exit the longitudinal grooves of the stator yoke at a stator yoke head and each protrude from the stator yoke, while extending parallel to the longitudinal axis LA, by a specified length L, wherein the individual wires of each compressed strand are electrically conductively connected at the ends of the compressed strand, and at least one first end of a first compressed strand, which first compressed strand protrudes from one of the stator yoke heads, is electrically conductively joined to a second end of another, second compressed strand, the second compressed strand protrudes from the same stator yoke head and comes from another longitudinal groove, by a separate electrically conductive connecting element in order to form an electrical winding, wherein the first end and the second end mechanically do not touch each other.

2. The stator according to claim 1, wherein the connecting element is designed as a metal bracket.

3. The according to claim 1, wherein the connecting element is bent along its longitudinal direction.

4. The stator according to claim 1, wherein the connecting element is designed as a bent copper band.

5. The stator according to claim 1, a wherein the connecting element has a web-like, staple-like, beam-like, or U-shaped longitudinal profile.

6. The stator according to claim 1, wherein end faces of the connecting elements lie essentially in a plane arranged perpendicular to the longitudinal axis.

7. The stator according to claim 1, wherein the connecting elements have two or three contact projections extending perpendicular to a longitudinal direction of the connecting element.

8. The stator according to claim 1, wherein the connecting element has a changing cross-section in a direction of current flow, the cross-section is sometimes larger, equal, and smaller than a sum of the cross-sections of all the individual wires of a compressed strand directly connected to the connecting element.

9. The stator according to claim 1, wherein ends of a compressed strand protrude from the stator yoke heads by a length L which is smaller than a limit value G1, wherein the limit value G1 is smaller than ten times the largest diameter D of a cross-section of the compressed strands: G1<10*D.

10. The stator according to claim 1, wherein the individual wires of each compressed strand are mechanically compacted at their ends by ultrasound and electrically connected by laser welding.

11. The stator according to claim 1, wherein the first end is electrically conductively joined by laser welding to a first end of the connecting element and the second end is electrically conductively joined by laser welding to a second end of the connecting element.

12. The stator according to claim 1, in wherein each of the compressed strands, at least in an area in which the compressed strands run in the longitudinal grooves, has an electrically insulating sheathing, which electrically insulates the respective compressed strand from other compressed strands introduced in the respective longitudinal groove and from the stator yoke.

13. The stator according to claim 1, wherein the conductive connecting element is curved in its longitudinal direction.

14. The stator according to claim 1, wherein end faces of at least one third of all joined connecting elements of a stator yoke head lie in a plane which is substantially perpendicular to the longitudinal axis LA.

15. The stator according to claim 1, wherein one or more of the connecting elements are thermally connected to a heat sink.

16. An electric motor or generator with a stator according to claim 1.

17. A vehicle with the electric motor or generator according to claim 16.

18. (canceled)

19. The vehicle according to claim 17, wherein the vehicle is a motor vehicle, a rail vehicle, a watercraft, an underwater vehicle, a spacecraft, a golf cart, a cable-guided shuttle, an industrial truck, a hoist, an aircraft, a construction machine, or a machine tool.

20. A method of producing a stator with a stator yoke for an electrical machine, the method comprising: provisioning a stator yoke which has longitudinal grooves extending along its inner peripheral edge and parallel to it along a longitudinal axis LA of the stator yoke, each of the longitudinal grooves being separated by stator teeth; provisioning compressed strands, each consisting of several electrically insulated individual wires; introducing one or more compressed strands into the respective longitudinal grooves, wherein respective ends of the compressed strands exit the longitudinal grooves of the stator yoke at a respective stator yoke head and protrude from the stator yoke parallel to the longitudinal axis LA by a specified length L; and electrically conductively joining at least a first end of a first compressed strand protruding from one of the stator yoke heads to a second end of another, second compressed strand protruding from the same stator yoke head and coming from a different longitudinal groove to form an electrical winding via a separate electrically conductive connecting element, wherein the first end and the second end do not mechanically touch each other.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In the drawings:

[0039] FIG. 1 shows a stator with electrically and mechanically connected compressed strands (prior art);

[0040] FIG. 2 is a schematic representation of a stator according to one embodiment of the invention;

[0041] FIG. 3 is a top view of the stator yoke head 110a of the stator according to FIG. 2;

[0042] FIG. 4 is a top view of the stator yoke head 110b of the stator according to FIG. 2;

[0043] FIG. 5a is a schematic view of the end face of a connecting element 114;

[0044] FIG. 5b is a schematic side view of a connecting element according to FIG. 5a in a first variant;

[0045] FIG. 5c is a schematic side view of a connecting element according to FIG. 5a in a second variant; and

[0046] FIG. 6 is a schematic representation of a method according to the invention for producing a stator.

DETAILED DESCRIPTION

[0047] FIG. 1 shows a stator for an electrical machine, in particular an electric motor and/or a generator with electrically and mechanically connected compressed strands according to the prior art. The stator shown has a fundamentally cylindrical stator yoke 100 which, along its inner peripheral edge, has left grooves (not shown) which extend parallel to a longitudinal axis LA of the stator yoke 100 and are each separated by stator teeth (not shown).

[0048] In the present case, two compressed strands 106 are introduced into the longitudinal grooves, each of which consists of a plurality of individual wires (not shown), each of which is electrically insulated. The respective compressed strands 106 exit the longitudinal grooves of the stator yoke 100 on the respective stator yoke heads 110a, 110b and then run at an angle such that they are mechanically and electrically connected to the respective ends 112a, 112b of the compressed strands to form stator windings with a different compressed strand of another longitudinal groove.

[0049] For example, the end 112b of the compressed strand 106a is electrically and mechanically connected to form the end 112b of the compressed strand 106b (runs behind the visible compressed strand of the outer ring). The compressed strand 106b is also electrically and mechanically connected at its end 112a directly to the end 112a of the compressed strand 106c, etc. This type of electrical connection of the ends 112a, 112b of the compressed strand 106, 106a-106c protrudes from the stator yoke heads by a length LL.

[0050] FIG. 2 shows a schematic representation of a stator for an electrical machine, in particular for an electric motor and/or a generator according to an example embodiment of the invention, wherein the stator, as in FIG. 1, has a stator yoke 100 which has longitudinal grooves 101 that extend parallel along its inner peripheral edge along a longitudinal axis LA of the stator yoke 100, which grooves are each separated by stator teeth 102. As in FIG. 1, one or more compressed strands 106 are each introduced into the longitudinal grooves 101, each of which consists of a plurality of electrically insulated individual wires (not shown). The individual wires of the compressed strands 106 are connected in an electrically conductive manner at their ends 112a, 112b.

[0051] In contrast to FIG. 1, the respective ends 112a, 112b of the compressed strands 106 exit the longitudinal grooves 101 of the stator yoke 100 on the respective stator yoke head 110a, 110b parallel to the longitudinal axis LA and thus protrude from the respective stator yoke head according to the invention in a parallel orientation to the longitudinal axis LA by a specified length L. The compressed strands 106 thus run essentially straight from one end 112a to the opposite end 112b. The length L for the left stator yoke head 110a is uniformly L1 for all compressed strands 106 and for the right stator yoke head 110b uniformly L2 for all compressed strands 106. In the present case, L1L2. In the present case, however, all of the compressed strands 106 have the same length. The following may apply in other example embodiments according to the invention: L1=L2=L. For special applications, the length L on a stator yoke head 110a, 110b can also be different for at least two compressed strands.

[0052] Furthermore, in contrast to FIG. 1, at least a first end 112a, 112b of a first compressed strand 106 protruding from one of the stator yoke heads 110a, 110b is electrically conductively joined to a second end 112a, 112b of another, second compressed strand 106 protruding from the same stator yoke head 110a, 110b and coming from another longitudinal groove 104 to form an electrical winding via a separate electrically conductive connecting element 114, wherein the first end 112a, 112b and the second end 112a, 112b do not mechanically touch each other.

[0053] It can also be seen from FIG. 2 that some of the connecting elements 114 have on their end face 119 coaxial to the longitudinal axis LA connecting pins 118 which rise above the stator yoke 100 and are used for electrical contacting of the windings realized in the stator 100. Some of the connecting elements 114 serve for the electrical connection of two compressed strand ends 112a, 112b. In turn, some connecting elements 114 are used here for the electrical connection of three compressed strand ends 112a, 112b.

[0054] The connecting elements 114 shown here are copper strips bent in the longitudinal direction with a strip width 1 or 2 in the range from 5 mm to 40 mm and a strip thickness of 0.2 mm to 5 mm. The overall length BL of the stator shown in the present example embodiment results in: BL=1+L1+LS+L2+2. In comparison to the stator of FIG. 1, the stator of FIG. 2, as far as the winding guidance outside of the stator yoke 100 is concerned, is more compact and thus saves material and weight.

[0055] The major part of the heat generated during operation of the electrical machine can be dissipated by thermal contact of the connecting elements 114 with a heat sink. It is advantageous for the thermal coupling for heat dissipation that the end faces 119 of the connecting elements 114 on the respective stator yoke head 110a, 110b are essentially in a plane perpendicular to the longitudinal axis LA. In terms of construction technology, this makes it possible to easily implement various known heat couplings. It is essential here that the thermal coupling is made from a non-electrically conductive material.

[0056] The compressed strand ends 112a, 112b protruding from the stator yoke 100 are advantageously connected to the respective connecting element by ultrasonic compacting and subsequent laser welding.

[0057] FIG. 3 shows a top view of the stator yoke head 110a of the stator yoke 100 according to FIG. 2. In this top view, the end faces of the connecting elements 114, which are each curved in the longitudinal direction, can be clearly seen. A plurality of the connecting elements 114**/114*** connect the ends of two compressed strands protruding from the stator yoke 110 on the stator yoke head 110a. Some of the connecting elements 114* connect the ends of three compressed strands protruding from the stator yoke 110 on the stator yoke head 110a. Furthermore, some of the ends of the compressed strands are electrically connected to a connecting pin 118, which is used to connect the electrical windings realized in the stator yoke 100.

[0058] FIG. 4 shows a top view of the stator yoke head 110b of the stator yoke according to FIG. 2. The end faces of the connecting elements 114, which are each curved in the longitudinal direction, can also be clearly seen in this top view.

[0059] FIG. 5a shows a schematic plan view of the end face of a connecting element 114, preferably made of copper.

[0060] FIG. 5b shows a schematic side view of a connecting element 114 according to FIG. 5a in a first variant. FIG. 5c shows a schematic side view of a connecting element according to FIG. 5a in a second variant.

[0061] FIG. 6 shows a schematic representation of a method according to the invention for producing a stator with a stator yoke 100 for an electrical machine, in particular for an electric motor and/or a generator. The method includes the following steps.

[0062] In step 201, a stator yoke 100 is provided which, along its inner peripheral edge, has longitudinal grooves (101) extending parallel and along a longitudinal axis LA of the stator yoke (100), each of which is separated by stator teeth (102). In step 202, compressed strands 106 are provided, each consisting of a plurality of electrically insulated individual wires. In step 203, one or more compressed strands 106 are introduced into the respective longitudinal grooves 101, wherein respective ends 112a, 112b of the compressed strands 106 exit the longitudinal grooves 101 of the stator yoke 100 on a respective stator yoke head 110a, 110b and protrude from the stator yoke 100 along the longitudinal axis LA by a specified length L. In step 204, there is an electrically conductive joining of at least a first end 112a, 112b of a first compressed strand 106 protruding from one of the stator yoke heads 110a, 110b to a second end 112a, 112b of another, second compressed strand 106 protruding from the same longitudinal stator yoke head 110a, 110b to form an electrical winding via a separate electrically conductive connecting element 114, wherein the first end (112a, 112b) and the second end 112a, 112b do not mechanically touch each other.

[0063] Although the invention has been illustrated and explained in greater detail using preferred example embodiments, the invention is not limited by the disclosed examples and other variations may be derived therefrom by a person skilled in the art without departing from the scope of protection of the invention. It is therefore clear that there are a plurality of possible variations. It is also clear that embodiments cited by way of example actually only constitute examples that are not to be interpreted in any way as a limitation of the scope, of the potential applications, or of the configuration of the invention. Instead, the preceding description and the description of the figures enable the person skilled in the art to specifically implement the example embodiments, wherein the person skilled in the art has knowledge of the disclosed inventive concept and is able to make numerous changes, for example, with respect to the function or the arrangement of individual elements cited in an example embodiment, without departing from the scope of protection, which is defined by the claims and their legal equivalents, such as a further explanation in the description.

LIST OF REFERENCE NUMERALS

[0064] 100 Stator yoke [0065] 101 Internal longitudinal grooves in the stator yoke [0066] 102 Stator teeth [0067] 103 Mechanical and electrical connection of two ends of two compressed strands [0068] 106 Compressed strands [0069] 106a, 106b, 106c Compressed strands [0070] 110a, 110b Stator yoke head [0071] 112a, 112b Ends of the compressed strands, preferably with compacted and electrically connected individual wires [0072] 114 Connecting element [0073] 118 Connecting pin [0074] 119 End face [0075] 201-204 Method steps