METHOD FOR PRODUCING A SKEWED STATOR

Abstract

A method for producing a skewed stator having a stator winding made from segmented conductors includes providing a stator core having a large number of axially layered stator core elements which form a plurality of slots extending from one end-face of the stator core to an opposite end-face, and which extend parallel in an axial direction. A large number of segmented conductors are provided which each have two leg portions extending parallel to each other and a connection portion electrically connecting the leg portions. The leg portions are introduced into the slots, and the stator core elements are rotated in a circumferential direction so they are displaced relative to each other in a circumferential direction and the slots form an inclination in a circumferential direction. The leg portions are bent by the rotation have an inclination corresponding to the slots. The stator core elements are fixed relative to each other.

Claims

1. A method for producing a skewed stator which has a stator winding made from segmented conductors, comprising the following steps: providing a stator core which has a large number of axially layered stator core elements, wherein the stator core elements form a plurality of slots of the stator core which extend from a first end face of the stator core to an opposite second end face of the stator core and which extend parallel in an axial direction; providing a large number of segmented conductors which each have two leg portions which extend parallel to each other and a connection portion which connects the leg portions in an electrically conductive manner; introducing the leg portions into the slots; rotating stator core elements of the stator core in a circumferential direction so that the stator core elements are displaced relative to each other in a circumferential direction and the slots form an inclination in a circumferential direction, wherein the leg portions are bent by the rotation and receive an inclination corresponding to the inclination of the slots; and fixing the stator core elements relative to each other so that the inclination of the slots is maintained.

2. The method according to claim 1, wherein in the rotation step the external stator core element at the first end face and/or portions, which project at the first end face out of the stator core, of the segmented conductors are retained by means of a first retention tool, and the external stator core element at the second end face and/or portions, which project at the second end face out of the stator core, of the segmented conductors are retained by means of a second retention tool, and a rotational movement is carried out in a circumferential direction of the retention tools relative to each other so that the leg portions also move the stator core elements which are arranged between the external stator core elements.

3. The method according to claim 2, wherein the first retention tool and/or the second retention tool comprise(s) radially movable retention elements and the retention elements have a radial projection for each slot, wherein the projections are moved radially inwardly at angular positions between the slots and retain at that location the portions, which project out of the stator core, of the segmented conductors.

4. The method according to claim 2, wherein the first retention tool and/or the second retention tool has/have an annular frame which is fixed to the stator core in order to retain the external stator core element.

5. The method according to claim 3, wherein the retention elements are mounted in the frame radially movable.

6. The method according to claim 1, wherein the inclination of the slots and/or the leg portions is helical.

7. The method according to claim 1, wherein the stator core elements are rotated until an axial opening of a respective slot is located in a circumferential direction at the first end face at an angular position, at which an axial opening of a directly adjacent slot is located at the second end face.

8. The method according claim 1, wherein as many segmented conductors are provided that the leg portions of the segmented conductors fill radially layered all the slots of the stator core.

9. The method according to claim 1, wherein an electrically insulating slot liner is or becomes introduced into a respective slot before the leg portions are introduced, which slot liner is accordingly deformed during the step of rotating the inclination of the slots.

10. The method according to claim 2, wherein the first retention tool and/or the second retention tool has/have an annular frame which is fixed to the stator core in order to retain the external stator core element.

11. The method according to claim 2, wherein the retention elements are mounted in the frame radially movable.

12. The method according to claim 2, wherein the inclination of the slots and/or the leg portions is helical.

13. The method according to claim 2, wherein the stator core elements are rotated until an axial opening of a respective slot is located in a circumferential direction at the first end face at an angular position, at which an axial opening of a directly adjacent slot is located at the second end face.

14. The method according claim 2, wherein as many segmented conductors are provided that the leg portions of the segmented conductors fill radially layered all the slots of the stator core.

15. The method according to claim 2, wherein an electrically insulating slot liner is or becomes introduced into a respective slot before the leg portions are introduced, which slot liner is accordingly deformed during the step of rotating the inclination of the slots.

16. The method according to claim 3, wherein the first retention tool and/or the second retention tool has/have an annular frame which is fixed to the stator core in order to retain the external stator core element.

17. The method according to claim 3, wherein the retention elements are mounted in the frame radially movable.

18. The method according to claim 3, wherein the inclination of the slots and/or the leg portions is helical.

19. The method according to claim 3, wherein the stator core elements are rotated until an axial opening of a respective slot is located in a circumferential direction at the first end face at an angular position, at which an axial opening of a directly adjacent slot is located at the second end face.

20. The method according claim 3, wherein as many segmented conductors are provided that the leg portions of the segmented conductors fill radially layered all the slots of the stator core.

Description

[0026] Additional advantages and details of the present invention will be appreciated from the embodiments, which are described below and with reference to the drawings. These drawings are schematic illustrations in which:

[0027] FIG. 1 shows a flow diagram of an embodiment of the method according to the invention;

[0028] FIG. 2 shows a front view of a stator core, which is used in the context of the method;

[0029] FIG. 3 shows a schematic view of a segmented conductor which is used in the context of the method;

[0030] FIG. 4 shows a schematic view of a slot with leg portions, which are arranged therein, of the segmented conductors;

[0031] FIG. 5 shows a schematic view of an operation for introducing segmented conductors in the stator core in the context of the method;

[0032] FIG. 6 shows a schematic view of the segmented conductors introduced into the stator core;

[0033] FIG. 7 shows a partially sectioned front view of a retention tool which is used in the context of the method in a position which is arranged on the stator core; and

[0034] FIG. 8 shows an example of a vehicle having an electrical machine, which has a stator, which is obtained by the method according to the invention.

[0035] FIG. 1 shows a flow diagram of an embodiment of a method according to the invention for producing a skewed stator.

[0036] The method comprises a first step S10, in which a stator core 1, which is in particular in the form of a sheet metal assembly, is provided.

[0037] FIG. 2 shows a front view of the stator core 1.

[0038] In this case, the stator core 1 comprises by way of example 54 slots 2 which extend from a first end face 3 which is shown in FIG. 2 to an opposite second end face 4 (see FIG. 3). The stator core 1 has a large number of axially layered stator core elements 5, 5a, 5b (see also FIG. 6), in particular in the form of individual metal sheets or stator metal sheets which are, for example, from 0.27 mm to 0.5 mm thick. FIG. 2 shows an axially external stator core element 5a at the first end face 3. Each stator core element 5, 5a, 5b has a large number of through-openings 6 which form the slots 2 of the stator core 1. In this case, the through-openings 6 of the stator core elements 5, 5a, 5b are arranged loosely one on the other in a congruent manner so that the slots 2 extend parallel in an axial direction.

[0039] The step S10 of providing the stator core 1 comprises in this embodiment three sub-steps S11 to S13: in the sub-step S11, the large number of stator core elements 5, 5a, 5b, which are typically formed by stamping are provided. In the subsequent sub-step S12, the stator core elements 5 are arranged, in an axially layered state, loosely one on the other so that the through-openings 6 form the linear extending slots 2. In the sub-step S13, an electrically insulating slot liner 7 which is made from insulating paper is introduced into each slot 2 (see FIG. 4), which slot liner 7 extends completely in an axial direction between the end faces 3, 4 and completely lines the slot 2 in a circumferential direction.

[0040] FIG. 3 shows a schematic view of a segmented conductor 8, which is used in the context of the method. FIG. 4 shows a schematic view of a slot 2 with segmented conductors 8 received therein.

[0041] The segmented conductor 8 comprises two leg portions 9, which extend in a parallel manner in an axial direction and a connection portion 10, which connects the leg portions 8 in an electrically conductive manner. The connection portion 10 is constructed in such a manner that the leg portions 9, when they are introduced into the slots 2, are arranged in different slots 2 and in different radial layers inside a respective slot 2. To this end, FIG. 4 shows that eight leg portions 9 in eight layers of a slot 2 which is lined by the slot liner 2 fill approximately 80% of the cross sectional surface—are of the slot 2. In an evident manner, the leg portions 9 have a cross section, which is rectangular in a rounded manner. In this case, each segmented conductor 8 is made from copper, wherein the leg portions 9 are constructed integrally with the connection portion 10.

[0042] FIG. 5 shows a schematic illustration of an operation for introducing segmented conductors 8 into the stator core 1 in the context of the method.

[0043] In a step S20 of the method, the segmented conductors 8 are provided. The step S20 comprises in this embodiment three sub-steps S21 to S23:

[0044] In the sub-step S21, a rod made of copper is provided. This rod is bent in the sub-step S22 so that, on the one hand, the connection portion 10 is formed and, on the other hand, the leg portions 9, which extend parallel to each other, are formed. The formation of the connection portion 10 is preferably carried out by rotational tensile bending, for example, by means of a 3D bending apparatus.

[0045] In the sub-step S23, so many segmented conductors 8 in the form of a segmented conductor basket are arranged in such a manner that the leg portions 9 of the segmented conductors 8 in a radially layered state completely fill or virtually fill all the slots 2 of the stator core 1. The segmented conductors 8 are arranged in such a manner that all the connection portions 10 are located at one axial end and all the free ends of the leg portions 9 are located at the other axial end of the segmented conductor basket.

[0046] In a step S30, the leg portions 9 are introduced into the slots 2 by a linear relative movement between the stator core 1 and the segmented conductors 8. The free ends of the leg portions 9 are introduced from the first end face 3 into the slots 2 until the free ends of the leg portions 9 project at the second end face 4 from the stator core 1. In this case, the free ends of the leg portions 9 do not touch the slot liners 7.

[0047] FIG. 6 is a schematic illustration of the segmented conductors 8, which are introduced into the stator core 1.

[0048] In a step S40, stator core elements 5, 5a, 5b of the stator core 1 are subsequently rotated in a circumferential direction so that the stator core elements 5, 5a, 5b are displaced relative to each other in a circumferential direction and the slots 2 form an inclination in a circumferential direction. In this case, the leg portions 9 are bent by the rotation and receive an inclination, which corresponds to the inclination of the slots 2.

[0049] The step S40 comprises the following sub-steps S41 and S42:

[0050] In the sub-step S41, the external stator core element 5a at the first end face 3 and portions, which project at the first end face 3, of the segmented conductors 8 are retained by means of a first retention tool 11, that is to say, substantially transition portions from the connection portion 10 to the leg portions 9. In a manner of speaking, the external stator core element 5b at the second end face 4 and portions, which project at the second end face 4, of the segmented conductors 8, that is, parts of the leg portions 9, are retained by means of a second retention tool 12. The retention tools 11, 12 are purely schematically illustrated in FIG. 6.

[0051] FIG. 7 is a partially sectioned front view of the first retention tool 11 in a position arranged on the stator core 1. The explanations relating to the first retention tool 11 apply similarly to the identically constructed second retention tool 12 in this case.

[0052] The first retention tool 11 comprises a number of retention elements 13 corresponding to the number of slots 2. The retention elements 13 as a whole have for each slot 2 a projection 14. Each retention element 13 comprises two projections 14 which are arranged at angular positions between the slots 2 and which retain every second projecting portion at both sides at that location. The projecting portions which are located therebetween are each retained at one side by a projection 14 of a pair of directly adjacent retention elements 13.

[0053] The first retention tool 11 further comprises an annular frame 15 which overlaps an external diameter of the stator core 1 in the position shown in FIG. 7. The retention elements 13 are mounted in a radially movable manner inside the frame 15. In the position of the retention elements 13 as shown in FIG. 7, they are in the radially innermost position thereof. In this case, in an evident manner, the projections 14 do not reach further in an inward direction than an internal diameter of the stator core 1 so that tooth heads 16 of the stator core 1 can be seen in FIG. 7.

[0054] In the sub-step S41, the first retention tool 11 is placed on the first end face 3 and the second retention tool 12 is placed on the second end face 4 from the axial direction. In this case, the retention elements 13 are located in the radially outermost position thereof in the frame 15. The frame 15 of the first retention tool 11 is fixed to the axially outermost stator core element 5a in order to retain it. Similarly, the frame 15 of the second retention tool 12 is fixed to the axially outermost stator core element 5b in order to retain it. Subsequently, the retention elements 13 of the retention tools 11, 12 are moved radially inwardly in order to retain the projecting portions of the segmented conductors 8.

[0055] In the sub-step S42, as can be seen in FIG. 6, the retention tools 11, 12 are rotated relative to each other in a circumferential direction so that the leg portions 9 also move the stator core elements 5, which are arranged, between the external stator core elements 5a, 5b. To this end, both retention tools 11, 12 are rotated in the present embodiment in opposite directions in a circumferential direction. According to alternative embodiments, the first retention tool 11 remains fixed during the rotational movement and only the second retention tool 12 is rotated in a circumferential direction, or vice versa.

[0056] In a subsequent step S50, the stator core elements 5, 5a, 5b are fixed relative to each other so that the inclination of the slots 2 is maintained. To this end, a plurality of weld seams are constructed at the radially external covering face of the stator core 1 by laser welding.

[0057] In a subsequent step S60, the free ends of the leg portions 9 are bent at the second end face 4 so that free ends of two different leg portions 9 abut each other. In a subsequent step S70, the abutting free ends are connected to each other in an electrically conductive manner and in a materially engaging manner by means of laser welding.

[0058] FIG. 8 shows a schematic illustration of an example of a vehicle 100 with an electrical machine 101, which has a stator 103, which is obtained by a method according to one of the above-described embodiments.

[0059] A non-inclined rotor 102 is rotatable mounted relative to the stator 103 inside the stator 103 of the electrical machine 101, which is in this case in the form of a permanently excited synchronous motor by way of example. It can be seen that only connection portions 10 of the segmented conductors 8 are located at the first end face 3 of the stator core 1 and only the welded free ends of the leg portions 9 of the segmented conductors 8 are located at the second end face 4 of the stator core 1.

[0060] The electrical machine 101 is configured to drive the vehicle 100. This vehicle 100 is in the form of a partially or completely electrically drivable vehicle, for example, a battery electric vehicle (BEV) or a hybrid vehicle.