Stator, electric machine, connection bridge and method for manufacturing a stator

Abstract

The invention relates to a stator which may be used within an electric rotating machine and a method for manufacturing a stator. The stator (200) comprises a stator core (100) having a plurality of slots (101, 101a, 101b) arranged in circumferential direction (C) of the stator core (100), a plurality of conductors (102, 103) forming a stator winding, wherein at least a radially outer conductor (102) and a radially inner conductor (103) are arranged along a radial direction (R) of each slot (101). At least one pair of a radially outer conductor (102) of a first slot (101a) and a radially inner conductor (103) of a second slot (101b) circumferentially spaced from the first slot (101a) is electrically connected by a connection bridge (1). The connection bridge (1) comprises a first base element (2) and a second base element (3) connected to a respective conductor (102, 103) and a top element (4) being connected to the base elements (2, 3) and preferably arranged in a larger distance from the stator core (100) than the first base element (2) and second base element (3).

Claims

1. A stator for a rotating electric machine, comprising: a stator core having a plurality of slots arranged in a circumferential direction of the stator core; and a plurality of conductors forming a stator winding, wherein: at least a radially outer conductor of the plurality of conductors and a radially inner conductor of the plurality of conductors are arranged along a radial direction of each slot of the plurality of slots, wherein respective axial end sections of the radially outer conductor and the radially inner conductor are protruding from respective slots of the plurality of slots on at least one side of the stator core; at least one pair of a radially outer conductor of the plurality of conductors arranged along a first slot of the plurality of slots and a radially inner conductor of a second slot of the plurality of slots circumferentially spaced from the first slot is electrically connected by a connection bridge; and the connection bridge comprises: a first base element and a second base element connected to the axial end sections of a respective conductor of the plurality of conductors by axial welding, and a top element that is connected to the first base element by welding from a radial outer side and to the second base element, after the first base element and the second base element are connected to the axial end sections of the respective conductor, by welding from a radial inner side and arranged at a larger distance from the stator core than a distance from the stator core to the first base element and the second base element.

2. The stator according to claim 1, wherein the first base element embraces at least one of a lateral part or an outwardly facing part of an outer surface of the respective axial end section of the radially outer conductor.

3. The stator according to claim 1, wherein the second base element embraces at least one of a lateral part or an inwardly facing part of an outer surface of the respective axial end section of the radially inner conductor.

4. The stator according to claim 1, wherein: the top element comprises a first connection end having a contact face in contact with a face of the first base element; and the top element comprises a second connection end having a contact face in contact with a face of the second base element.

5. The stator according to claim 4, wherein: an axial contact face of the first connection end is in contact with an axial face of the first base element; and an axial contact face of the second connection end of the top element is in contact with an axial face of the second base element.

6. The stator according to claim 1, the stator comprising a plurality of the connection bridges, wherein one or more of: first base elements are arranged within a first region of a lower holding member; second base elements are arranged within a second region of a lower holding member; or top elements are arranged within an upper holding member.

7. The stator according to claim 6, wherein one or more of the lower holding member or the upper holding member is annular.

8. The stator according to claim 6, wherein one or more of the lower holding member or the upper holding member comprises a body made of resin.

9. The stator according to claim 6, wherein one or more of the lower holding member or the upper holding member comprises at least one reference mark.

10. The stator according to claim 6, wherein one or more of the lower holding member or the upper holding member comprises at least one spacer element for defining an axial distance to one or more of the stator core or an axially adjacent holding member.

11. The stator according to claim 6, wherein the lower holding member comprises chamfered openings for introducing respective axial end sections of respective conductors of the plurality of conductors.

12. The stator according to claim 6, wherein: the first base element is arranged on a first axial level; and the second base element is arranged on a second axial level different from the first axial level.

13. The stator according to claim 12, wherein the second base element is arranged closer to the stator core than the first base element.

14. The stator according to claim 1, wherein one or more of the first base element or the second base element comprises anchoring openings at a lateral side.

15. The stator according to claim 1, wherein a number of one or more of first base elements or second base elements are connected to each other to form a termination connection on a termination side of the stator core.

16. The stator according to claim 1, wherein respective conductors of the plurality of conductors comprise respective stranded wires.

17. A connection bridge for connecting conductors arranged in slots arranged in a circumferential direction of a stator core of a stator, wherein the connection bridge comprises: a first base element and a second base element being connectable to respective axial end sections of the conductors by axial welding; and a top element configured to be connected to base elements by welding from a radial outer side or by welding from a radial inner side after the base elements are connected to the respective axial end sections of the conductors, wherein the top element is configured to be arranged at a larger distance from the stator core to the first base element and the second base element.

18. The connection bridge according to claim 17, wherein the top element comprises two contact faces for contacting respective faces of the first base element and the second base element.

19. A method for manufacturing a stator for a rotating electric machine, the stator comprising a stator core which has a plurality of slots arranged in a circumferential direction of the stator core and a plurality of conductors forming a stator winding, wherein at least a radially outer conductor and a radially inner conductor of the plurality of conductors are arranged along a radial direction of each slot of the plurality of slots, and respective axial end sections of respective conductors of the plurality of conductors protrude from respective slots of the plurality of slots on at least one side of the stator core, wherein respective axial end sections are connected by a connection bridge, said bridge comprising a first base element and a second base element connected to respective axial end sections of a respective conductor of the plurality of conductors and a top element connected to the first base element and the second base element, the method comprising: first: connecting at least one first base element to an axial end section of the radially outer conductor by axial welding, and connecting at least one second base element to the radially inner conductor by an axial end section of axial welding; and second: connecting a top element to the first base element from a radial outer side, and connecting the top element to the second base element from a radial inner side.

20. The method according to claim 19, comprising one or more of: providing a first region of a lower holding member carrying first base elements and placing the first region of the lower holding member close to the axial end sections of radially outer conductors; providing a second region of the lower holding member carrying second base elements and placing the second region of the lower holding member to the axial end sections of radially inner conductors; or providing an upper holding member carrying top elements and placing the upper holding member close to the first region of the lower holding member and the second region of the lower holding member after having connected the first base elements to the axial end sections of the radially outer conductors and the second base elements to the axial end sections of the radially inner conductors.

21. The method according to claim 20, further comprising: positioning the radially inner conductors and the radially outer conductors in respective slots of the plurality of slots of the stator core, wherein the axial end sections protrude from a first axial side and a second axial side of the stator core; connecting the axial end sections of the radially outer conductors with the first base elements arranged in the first region of the lower holding member and the axial end sections of the radially inner conductors with the second base elements arranged in the second region of the lower holding member on the first axial side; connecting the axial end sections of the radially outer conductors with the first base elements arranged in the first region of the lower holding member and axial end sections of radially inner conductors with second base elements arranged in a second region of a lower holding member on the second axial side; and connecting the upper holding member to the lower holding members on both sides, and by welding the top elements of the upper holding member to the second base elements of the second region of the lower holding member.

22. The method according to claim 20, further comprising: providing the radially inner conductors in an inner stator template; connecting the axial end sections of the radially inner conductors on a first axial side with the second base elements arranged in the second region of the lower holding member, which is fixed to a first region of a lower holding member of an opposite termination side, forming an inner subassembly; providing the radially outer conductors in an outer stator template; connecting the axial end sections of the radially outer conductors with the first base elements arranged in the first region of the lower holding member on a second axial side, which is connected to the second region of the lower holding member on the termination side, forming an outer subassembly; introducing the conductors of the inner subassembly into respective slots of the plurality of slots the stator core from the first axial side; introducing the conductors of the outer subassembly into the respective slots of the plurality of slots of the stator core from the second axial side opposite to the first axial side; connecting the axial end sections of the radially outer conductors on the first axial side with the first base elements arranged in the first region of the lower holding member of the inner subassembly; connecting the axial end sections of the radially inner conductors on the second axial side with the second base elements arranged the second region of the lower holding member of the outer subassembly; and connecting the upper holding member to the lower holding members on both axial sides by welding the top elements of the upper holding member to the base elements of the first region of the lower holding member, and by welding the top elements of the upper holding member to the base elements of the second lower region of the holding member.

Description

(1) The invention will now be described with reference to preferred embodiments and the drawings, which show:

(2) FIG. 1a a part of a first embodiment of a stator in a perspective view;

(3) FIG. 1b a part of the first embodiment of a stator with a first example of a connection bridge in top view;

(4) FIG. 1c a part of the first embodiment of a stator with a second example of a connection bridge in top view;

(5) FIG. 2a a part of the first embodiment of a stator in a perspective view;

(6) FIG. 2b a detail view of FIG. 2a;

(7) FIG. 3 a part of the first embodiment of a stator in a perspective view;

(8) FIG. 4 a part of a second embodiment of a stator in a perspective view;

(9) FIG. 5 a detailed view of a part of the embodiment of FIG. 4;

(10) FIG. 6 a detailed view of a part of a stator in a side view;

(11) FIG. 7 a detailed view of a part of the first embodiment of a stator in a perspective view;

(12) FIGS. 8-10 schematically steps of a first method for forming a stator;

(13) FIG. 11 an inner subassembly of the second embodiment of a stator in a perspective view;

(14) FIG. 12 an outer subassembly of the second embodiment of a stator in a perspective view;

(15) FIG. 13 schematically steps of a second method for forming a stator.

(16) FIG. 1a shows a first embodiment of a stator 200 in a perspective view. The stator 200 comprises a cylindrical stator core 100 with axially extending slots 101 arranged in circumferential direction C.

(17) Each slot 101 contains a radially outer conductor 102 and a radially inner conductor 103 (see FIGS. 1a, 1b) arranged along a radial direction R. For the sake of clarity only a few of the conductors 102, 103 are shown.

(18) The conductors 102, 103 are connected by connection bridges 1.

(19) The connection bridges 1 each comprise a first base element 2, a second base element 3 and a top element 4 being connected to the base elements 2, 3 at connection ends 5, 8.

(20) The base elements 2, 3 are arranged close to the stator core 100, whereas the top elements 4 are arranged on top of the first and second base elements 2, 3 and thus at a larger distance 17 from the stator core 100 than the first base elements 2 and the second base elements 3.

(21) As can be seen in FIG. 1b the connection bridge 1 may connect an outer conductor 102 of a first slot 101a and in inner conductor 103 of a second slot 101b or as shown in FIG. 1c, the connection bridge 1 may also connect two outer conductors 102.

(22) Alternatively, the connection bridge 1 may connect an inner conductor 103 of a first slot 101a and an inner conductor 103 of a second slot 101b, not shown in the figures.

(23) FIG. 2a shows a part of the first embodiment of a stator 200 in a perspective view. FIG. 2b shows a detail D of FIG. 2a.

(24) Axial end sections 104, 105 of the conductors 102, 103 protrude from the slots 101, which are only schematically shown.

(25) The first base elements 2 embrace a lateral part 108 and an outwardly facing part 109 of the surface of the axial end section 104 of radially outer conductors 102.

(26) The second base elements 3 embrace a lateral part 110 and an inwardly facing part 111 of the surface of the axial end section 105 of the radially inner conductors 103.

(27) The first base elements 2 are arranged in a radially outer first region 13a of a lower annular holding member 12 and the second base elements 3 are arranged within a radially inner second region 13b of the lower annular holding member 12.

(28) The first and second base elements 2, 3 may be connected to the inner and outer conductors 102, 103 by axially welding to form a reliable electrical connection.

(29) The first base elements 2 comprise axial faces 7a, 7b for contacting first connection ends 5 of the top element 4 (see FIG. 1a). The first connection ends 5 have an axial contact face (not explicitly shown) which may be brought into contact with the axial faces 7a, 7b.

(30) Analogously the second base elements 3 have axial faces 10a, 10b for contacting a second connection end 8 of top element 4 (see FIG. 1a). The second connection ends 8 have an axial contact face (not explicitly shown) which may be brought into contact with the axial faces 10a, 10b.

(31) Axial faces 7a, 7b may be arranged in the same plane or, as shown in the figures, may be arranged in different planes. The same holds for the axial faces 10a, 10b. The lower axial faces 7b may be on the same axial level as the outer conductors 102 and the lower axial faces 10b may be on the same axial level as the inner conductors 103.

(32) An axial welding tool 120 (see FIG. 9) may be directed to an area between the lower axial face 7b and the outer conductor 102 to form a connection between the first base element 2 and the outer conductor 102.

(33) Analogously an axial welding tool 120 (see FIG. 9) may be directed to an area between the lower axial face 10b and the inner conductor 103 to form a connection between the second base element 3 and the inner conductor 103.

(34) The top elements may be connected to the first and second base elements 2, 3 by radially welding to form a reliable electrical connection.

(35) FIG. 3 shows a part of the first embodiment of a stator 200 in a perspective view.

(36) The first base elements 2 are arranged within the first region 13a of the lower annular holding member 12 and the second base elements 3 are arranged within the second region 13b of the lower annular holding member 12.

(37) A radial welding tool 121 (see FIG. 10) may be directed to a connection area 24 between the upper axial face 7a and a respective top element from a radial outside of the stator core 100, and analogously to a connection area 25 between the upper axial face 10a and a respective top element from the radial inside of the stator core 100.

(38) All first base elements 2 and all second base elements 3 may be positioned with respect to the outer conductors 102 (see FIGS. 1a, 1b, 1c) and the inner conductors 103 (see FIG. 1a, 1b, 1c) in one step.

(39) The top elements 4 are arranged within an upper annular holding member 14.

(40) The holding members 12 and 14 are made of resin, such as thermal resistant polyamide PA, such as PIC.

(41) The upper holding member 14 may positioned on the first lower holding member 12, such that all top elements 4 are arranged on respective first and second base elements 2, 3 in one step. To facilitate circumferential alignment the lower holding member 12 and the upper holding member 14 each comprise a radially extending protrusion 15.

(42) There is a distance 6 between the first region 13a of the lower holding member 12 and the upper holding member 14 and a distance 9 between the second region 13b of the lower holding member 12 and the upper holding member 14. In this embodiment the distances 6, 9 are equal.

(43) The connection areas 24 between the axial faces 7a (see FIG. 2b) of the first base elements 2 and the top elements 4 are arranged between the lower holding member 12 and the upper holding member 14 such that a radial welding tool 121 may be directed to the areas 24 from a radial outside of the stator 200.

(44) Accordingly, the connection areas 25 between the axial faces 10a (see FIG. 2b) of the second base elements 3 and the top elements 4 are arranged between the lower holding member 12 and the upper holding member 14 such that a radial welding tool 121 may be directed to the areas 25 from a radial insider of the stator 200.

(45) The distances 6, 9 allow a welding tool 121 (see FIG. 10) accessing the first base elements 2 and the top elements 4 from a radial outside and the second base elements 3 and the top elements 4 from a radial inside.

(46) In the embodiment of FIG. 3, the first region 13a of the lower holding member 12 and the second region 13b of the lower holding member 12 have the same axial height 19.

(47) The axial faces 7a of the first base elements 2 and the axial faces 10a of the second base elements 3 are arranged on the same respective axial levels as for example shown in FIG. 2b.

(48) In an alternative embodiment, axial end sections 104, 105 of the inner and of the outer conductors may be arranged at different axial levels as shown in FIG. 5.

(49) FIG. 4 shows a part of a second embodiment of a stator 200 in a perspective view, wherein the first region 13a of the lower holding member 12 has a longer axial height 19 than the second region 13b of the holding member 12.

(50) In this embodiment the upper holding member 14 has a stepped shape as the top elements 4 have to be connected as well to the first base elements 2 as to the second base elements 3 which are arranged at different axial levels.

(51) Connection areas 24, 25 are arranged between the lower holding member 12 and the upper holding member 14 such that a radial welding tool may have access to the connection areas 24, 25. In this embodiment the connection areas 24 and 25 are not on the same axial level.

(52) FIG. 5 shows a detailed view of a part of the embodiment of FIG. 4. The outer conductors 102 protrude from the stator core 100 by a distance which is larger than the distance by which the inner conductors 103 protrude from the stator core 100. Hence the axial end sections 104 of the outer conductors 102 are more distanced from the stator core than the axial end sections 105 of the inner conductors 103.

(53) Accordingly the first base elements 2 which embrace the parts of the axial end sections 104 of the outer conductors 102 are more distanced from the stator core than the second base elements 3, which embrace parts of the axial end sections 105 of the inner conductors 103.

(54) The first base elements 2 comprise anchoring openings 23. Anchoring openings 23 may also be arranged in the second base elements 3 (not explicitly shown in the figure).

(55) Resin of a body 11 of the lower holding member 12 (indicated by dashed lines) may enter the anchoring openings to provide a tight and reliable fixation between the first base elements 2 and the lower holding member 12.

(56) The body 11 of the lower holding member 12 may comprise chamfered openings 22 (in the figure schematically indicated for one opening with dashed lines) for introducing the axial end sections 104.

(57) FIG. 6 shows a detailed view of a part of a stator 200 in a side view. The lower holding member 12 comprises an axially extending protrusion 16. The protrusion defines an axial distance 26 to the top face 114 of the stator core 100.

(58) Preferably, the lower holding member 12 comprises three equally distanced axially extending protrusions 16. These protrusions 16 provide for a defined horizontal orientation of the lower holding member 12.

(59) FIG. 7 shows a detailed view of a part of the first embodiment of a stator 200 in a perspective view. A termination connection 18 is arranged on a termination side 106 of the stator core 100.

(60) One of the first base elements 2 and a radially adjacent second base element 3 are made as a single piece which is a part of the termination connection 18. The termination connection 18 provides for an external electrical connection.

(61) Similarly, a termination connection 18 may be arranged inside the stator core 100 (not shown in the figures).

(62) Steps for a first method used for forming the first embodiment of a stator 200 are schematically shown in FIGS. 8-10.

(63) Alternatively, conductors 102, 103 are directly introduced into a stator core 100. Alternatively, stator core templates 112, 113 (see FIGS. 11-13) can be used.

(64) Radially outer conductors 102 and radially inner conductors 103 are positioned in slots 101 of a stator core 100, such that the axial end sections 104, 105 protrude from a first axial side 107 and a second axial side 106 (see FIG. 10) of the stator core 100.

(65) In a further step axial end sections 104 of the radially outer conductors 102 are connected with first base elements 2 and ends 105 of radially inner conductors 103 are connected with second base elements 3.

(66) The connection can be made with an axially directed laser tool 120.

(67) The first base elements 2 may be arranged in an annular first region 13a of a lower holding member 12 and the second base elements 3 may be arranged in an annular second region 13b of the lower holding member 12. In the shown embodiment all base elements 2, 3 are arranged in a common lower holding member 12.

(68) In a further step top elements of connection bridges (not shown in this figures) arranged in an annular upper holding member 14 may be connected to the base elements 2, 3 arranged in the lower holding member 12 at a first axial side 107 of the stator core.

(69) The connection can be made with a radially directed laser tool 121.

(70) Preferably similar steps are also performed on the second axial side 106 of the stator core 100.

(71) For manufacturing the second embodiment of a stator, in a second method a first inner subassembly 20 (see FIG. 11) and an outer subassembly 21 (see FIG. 12) may be provided.

(72) FIG. 11 schematically shows an inner subassembly 20 in a perspective view. Inner conductors 103 are arranged in slots of a stator core template 113.

(73) The inner conductors 103 are connected to second base elements 3 arranged in a second region 13b of a lower holding member 12. The connection may be formed by axial welding. The lower holding member 12 also carries first base elements 2 which are arranged in the radial outer second region 13b of the lower holding member 12 and which are not yet connected to a conductor.

(74) FIG. 12 shows an outer subassembly 21 in a perspective view. Outer conductors 102 are arranged in slots of a stator core template 112.

(75) The outer conductors 102 are connected to first base elements 2 arranged in a first region 13a of a lower holding member 12. The connection may be formed by axial welding. The lower holding member 12 also carries second base elements 3 which are arranged in radially inner region 13b of the lower holding member 12 and which are not yet connected to a conductor.

(76) FIG. 13 schematically shows steps of a first example of forming a stator 200.

(77) The conductors 103 of the inner subassembly 20 are introduced into the slots 101 of a stator core 100 from a first axial side 107.

(78) The conductors 102 of the outer subassembly 21 are introduced into the slots 101 of a stator core 100 from a second axial side 106.

(79) The radially outer conductors 102 may then be connected to the first base elements 2 of the inner subassembly 20 on the first axial side 107 and the radially inner conductors 103 may be connected to the second base elements 3 (see FIG. 9) of the outer subassembly 21 on the second axial side 107.

(80) In a further step, not shown in the figure, upper holding members may be placed adjacent to the lower holding members on both sides 106, 107 of the stator core 100 and top elements may be welded to base elements.