Stator of an electric machine

Abstract

The invention relates to a stator of an electric machine (2) having a stator body (3) which has stator teeth (4) and stator slots (5), wherein the stator slots (5) are each formed between tooth flanks (4f) of adjacent stator teeth (4), wherein an electric stator winding (6) runs through the stator slots (5), wherein the stator winding (6) has two separate winding parts (6.1, 6.2) which are joined to one another in an axial joining direction to form joining connections (8) and each comprise a multiplicity of conductor elements (10), wherein each of the joining connections (8) has a joining pair (11) of conductor elements (10) belonging to different winding parts (6.1, 6.2), wherein the conductor elements (10) of the respective joining pair (11) have joining sections (12) at the conductor ends facing one another, on each of which joining sections a joining recess (13) for receiving the respective other joining section (12) is provided, wherein the joining sections (12) of the respective joining pair (11) have joining surfaces (14) along their joining recess (13), which joining surfaces face one another and have a longitudinal extent in the axial direction, characterised in that the joining surfaces (14) of the joining pairs (11) each face one of the tooth flanks (4f) of the respective stator slot (5).

Description

[0001] Description

[0002] title

[0003] Stator of an electrical machine

[0004] State of the art

[0005] The invention is based on a stator of an electrical machine according to the preamble of the main claim.

[0006] A stator of an electrical machine is already known from US11557930 B2, comprising a stator body having stator teeth and stator slots formed between the stator teeth. The stator slots are each formed between tooth flanks of adjacent stator teeth. An electrical stator winding runs through the stator slots. The stator winding has two separate winding parts, which are joined together in an axial joining direction with respect to a stator axis, forming snap-in joints and each comprising a plurality of conductor elements, in particular U-shaped hairpins. Each of the joints has a joining pair of conductor elements belonging to different winding parts.The conductor elements of the respective joining pair have joining sections at the facing conductor ends, each of which has a joining recess for accommodating the other joining section and, due to the joining recess, a reduced conductor cross-section. The joining sections of the respective joining pair have joining surfaces along their joining recess that face each other, have a longitudinal extension in the axial direction, and face a slot base or a slot of the respective stator slot. At least one joining section of each joining pair is coated with an electrically conductive bonding material. To bond the two winding parts, the joining sections of the joining pairs are pressed against each other in the axial and radial directions. The bonding material at the joining sections is then heated, thereby bonding the joining pairs and thus the two winding parts. Advantages of the invention.

[0007] The stator of an electrical machine according to the invention with the characterizing features of the main claim has the advantage that the two winding parts of the stator winding can be easily connected without a material bond, i.e., in particular, without soldering or welding. The solution according to the invention is well suited, for example, to connecting the two winding parts with a force-locking and / or positive connection. The force-locking of the joints can be created when the two winding parts are inserted into the stator slots or subsequently after the two winding parts have been assembled.

[0008] This can be achieved according to the invention in that the joining surfaces of the joining pairs each face one of the tooth flanks of the respective stator slot.

[0009] When inserting the winding parts into the stator slots, only low axial press-in forces are required to create the force-locking and / or form-locking joints.

[0010] The measures listed in the subclaims enable advantageous further developments and improvements of the stator of an electrical machine specified in the main claim.

[0011] It is very advantageous if the joining surfaces of the joining pairs are each designed in such a way that during joining an at least partial plastic deformation of the joining surfaces can be generated with support on the respective tooth flanks.

[0012] In this way, a frictional connection between the two winding parts can be achieved as soon as the two winding parts are inserted into the stator slots. The joining surfaces or joining sections of the respective joining pairs are supported on the tooth flanks of the respective stator slots during joining, enabling high frictional forces at the joining surfaces, which create very close contact at least between sections of the joining surfaces. Furthermore, a low electrical contact resistance of the joining connections can be achieved in this way.

[0013] The conductor cross-sections of the conductor elements have a conductor width that extends circumferentially between the tooth flanks and a conductor height that extends radially relative to the stator axis. To create the reduced conductor cross-sections of the joining sections, the conductor width of the joining sections is reduced across the full conductor height of the joining section.

[0014] It is particularly advantageous if the joining surfaces of the respective joining pair have two corresponding compression sections that, when sliding against each other, clamp due to an excess between the tooth flanks, thereby increasing sliding friction between the compression sections to generate plastic deformation of the joining surfaces, particularly the compression sections. During the plastic deformation of the joining surfaces, oxide layers are removed from the joining surfaces and / or plastically displaced, thus reducing the electrical contact resistance of the joints.

[0015] It is also advantageous if the pressing sections of the joining surfaces are plastically deformed, particularly to reduce the air gap formed between the joining surfaces. This creates intimate local contact between the joining surfaces of the respective joining pair, thereby reducing the electrical contact resistance of the joints.

[0016] It is very advantageous if a slot insulation, in particular an insulating paper or insulating laminate, is provided in each of the stator slots, which is in particular expandable to encapsulate the joints to protect them from oxidation and / or from cooling media and / or in particular has a collar for axial support on the stator body. When the slot insulation expands, it fits closely against the joints, thereby tightly or quasi-tightly enclosing them. The joints are thus protected from oxidation and / or from the influence of cooling media. This prevents a deterioration in the electrical contact resistance after joining or maintains the low electrical contact resistance. A collar on the slot insulation can prevent the slot insulation from being axially displaced when the joints are joined.The expansion of the slot insulations can be thermally activated, for example. Alternatively or additionally, the expansion of the slot insulations after insertion of the two winding parts can cause a tensioning of the joining sections of the respective joining pairs in the respective stator slot and thus a subsequent force-locking of the joining connections. It is also advantageous if the joining sections of each joining pair form a snap-in connection, with each joining section having a locking hook leading in the joining direction and a trailing locking recess on its joining surface, with the compression sections being formed in particular on the locking hooks. The snap-in connections achieve positive-locking joints that can absorb high pull-out forces, so that the two winding parts can be securely and permanently connected mechanically and electrically.According to the invention, the positive locking connections can be connected in a force-locking manner with support on the tooth flanks of the respective stator slot.

[0017] Furthermore, it is advantageous if, to form the joining pairs, two different joining sections are provided and formed on the two winding parts, wherein a first joining section of the respective joining pair additionally has a guide leading the latching hook of the first joining section in the joining direction, the conductor width of which is in particular smaller than the conductor width of the remaining part of the first joining section, and wherein a second joining section of the same joining pair additionally has a counter-guide trailing the latching recess of the second joining section in the joining direction for guiding the leading guide of the first joining section, the conductor width of which is in particular larger than the conductor width of the remaining part of the second joining section. In this way, the joining sections are guided in a defined manner during the joining of the latching connections, so that the latching connections can be produced reliably and reproducibly with low electrical contact resistance.

[0018] It is also advantageous if the locking hooks each have an entry area, in particular a chamfer, bevel, curvature, or rounded section. This facilitates the joining of the locking connections.

[0019] The joined sections of the respective joining pair advantageously form a full conductor cross-section. This way, the joints do not heat up more than the other sections of the conductor elements.

[0020] It is also advantageous if adjacent joints located in the same stator slot are offset from one another in the axial direction. This ensures that no unwanted electrical breakdown occurs due to voltage differences between the joints. It is further advantageous if at least one joining surface of the respective joining pair is coated to reduce contact resistance, activate the surface, or create a material bond. In this way, the joints can be improved electrically and / or mechanically after the two winding parts have been assembled. Furthermore, it is possible to subsequently convert the joints into material-fit joints after the initial force-fit joining of the joints.The material-to-material joining connections can be achieved, for example, by coating at least one joining surface of the joining pairs with a medium, for example a solder.

[0021] The invention further relates to an electrical machine with a stator according to the invention.

[0022] drawing

[0023] An embodiment of the invention is shown in simplified form in the drawing and explained in more detail in the following description.

[0024] They show:

[0025] Fig.1 shows a stator according to the invention with two still unassembled winding parts of a stator winding,

[0026] Fig.2 is a partial view of the stator according to the invention according to Fig.1 with winding parts mounted and joined to the stator,

[0027] Fig.3 a conductor bundle of one of the two winding parts according to Fig.1 and Fig.2 with joining sections at the conductor ends for forming the joining connections for joining the two winding parts,

[0028] Fig.4 shows a section along the line IV-IV in Fig.2 through one of the stator slots of the stator and through the joining connections of the conductor bundle located there, Fig.5A shows two joining sections of a joining pair of conductor elements belonging to different winding parts in the state before joining, Fig.5B shows the two joining sections of the joining pair according to Fig.5A in the state in which the pressing sections are sliding onto one another during joining, Fig.5C shows the two joining sections of the joining pair according to Fig.5A in the state after joining.

[0029] Description of the embodiment

[0030] Fig.1 shows a stator according to the invention with two still unassembled winding parts of a stator winding.

[0031] The stator 1 of an electrical machine 2 according to the invention has a stator body 3, in particular a stator laminated core, which has stator teeth 4 and stator slots 5 formed between the stator teeth 4. The stator slots 5 are each formed between tooth flanks 4f of adjacent stator teeth 4. An electrical stator winding 6 runs through the stator slots 5. The stator winding 6 has two separate winding parts 6.1, 6.2, which are joined together in an axial joining direction with respect to a stator axis 7, forming joining connections 8 and each comprising a plurality of conductor elements 10, in particular U-shaped hairpins. Each of the joining connections 8 is formed from a joining pair 11 of conductor elements 10 belonging to different winding parts 6.1, 6.2. The joining connections 8 of the stator winding 6 are located in the stator slots 5.

[0032] To form the joining connections 8, the conductor elements 10 of the two winding parts 6.1, 6.2 have joining sections 12 at conductor ends facing each other.

[0033] A slot insulation 15, in particular an insulating paper or insulating laminate, is provided in each of the stator slots 5.

[0034] To produce the stator according to the invention, the following steps are advantageously carried out: In a first step, the stator body 3, the two winding parts 6.1, 6.2 and the slot insulations 15 are provided. In a second step, the slot insulations 15 are introduced, in particular inserted, into the stator slots 5 of the stator body 3. In a third step, the two winding parts 6.1, 6.2 are inserted into the stator slots 5 from opposite end faces of the stator body 3 in the axial direction, wherein the joining sections 12 of the two winding parts 6.1, 6.2 are moved towards one another within the stator slots 5 and joined within the stator slots 5. In a fourth step, the stator 1, if expandable slot insulations 15 are present, can be heated to expand the slot insulations 15.

[0035] An alternative method (not shown) provides the following steps for producing the stator according to the invention: In a first step, two separate sub-packets of the stator body 3, the two winding parts 6.1, 6.2 and slot insulations for the separate sub-packets of the stator body 3 are provided. In a second step, the slot insulations 15 and then the first winding part 6.1 are mounted in the stator slots 5 of the first sub-packet. In a third step, the slot insulations 15 and then the second winding part 6.2 are mounted in the stator slots 5 of the second sub-packet. In a fourth step, the populated first sub-packet and the populated second sub-packet are joined together in the axial direction with respect to the stator axis while simultaneously joining the two winding parts. In a fifth step, the two sub-packets of the stator body 3 are materially joined to one another, in particular welded.In a sixth step, the stator 1, if expandable slot insulations 15 are present, can be heated to expand the slot insulations 15.

[0036] Fig.2 shows a partial view of the stator according to the invention according to Fig.1 with winding parts mounted and joined to the stator.

[0037] Each of the winding parts 6.1, 6.2 has a winding head 6k arranged on one of the end faces of the stator body 3 and extends from its winding head 6k into the stator slots 5.

[0038] Adjacent joints 8 located in the same stator slot 5 are, for example, offset from one another in the axial direction with respect to the stator axis 7.

[0039] Fig.3 shows a conductor bundle of one of the two winding parts according to Fig.1 and Fig.2 with joining sections at the conductor ends to form the joining connections for joining the two winding parts.

[0040] The conductor bundles 20 of each winding part 6.1, 6.2 each comprise several

[0041] Conductor legs 10s of several conductor elements 10 are each provided for insertion into one of the stator slots 5. All conductor legs 10s of the conductor bundle 20 are arranged one above the other in the radial direction.

[0042] At the joining sections 12 of the conductor elements 10, a joining recess 13 is provided for receiving a joining section 12 of a conductor element 12 of the respective other winding part 6.1, 6.2. Due to their joining recess 13, the joining sections 12 each have a reduced conductor cross-section. The joined joining sections 12 of the respective joining pair 11 together form a full conductor cross-section.

[0043] In addition, the joining sections 12 each have a joining surface 14 along their joining recess 13, which has a longitudinal extension in the axial direction with respect to the stator axis 7.

[0044] The joining sections 12 of each joining pair 11 can, for example, form a snap-in connection, with each joining section 12 having, on its joining surface 14, a snap-in hook 17 leading in the joining direction and a trailing snap-in recess 18. The snap-in recess 18 of a joining section 12 is recessed relative to the snap-in hook 17 of the same joining section 12. Each snap-in hook 17 forms an undercut 19, behind which the snap-in hook 17 of the other joining section 12 of the joining pair 11 can snap into place and which leads into the respective snap-in recess 18. The transition from the snap-in hook 17 to the snap-in recess 18 of the same joining section 12 is, for example, step-shaped or ramp-shaped.

[0045] Each locking recess 18 is provided for receiving the locking hook 17 of the other joining section 12 of the joining pair 11.

[0046] The locking hooks 17 can each have an inlet area 17f, in particular a chamfer, bevel, curvature or rounding.

[0047] For example, adjacent conductor legs 10s of a conductor bundle 20 of a winding part 6.1, 6.2 are designed to have different lengths.

[0048] Fig. 4 shows a section along line IV-IV in Fig. 2 through one of the stator slots of the stator and through the joining connections of the conductor bundle located there. According to the invention, the joining surfaces 14 of the joining pairs 11 each face one of the tooth flanks 4f of the respective stator slot 5.

[0049] According to the exemplary embodiment, the joining surfaces 14 of the joining pairs 11 can each be designed in such a way that during joining an at least partial plastic deformation of the joining surfaces 14 can be produced with support on the respective tooth flanks 4f.

[0050] The conductor cross-sections of the conductor elements 10 have a conductor width b, which extends in the circumferential direction between the tooth flanks 4f, and a conductor height h, which extends in the radial direction with respect to the stator axis 7.

[0051] To form the reduced conductor cross-sections of the joining sections 12, the conductor width b of the joining sections 12 is reduced over the full conductor height h of the joining section 12.

[0052] The slot insulations 15 are expandable, for example, to encapsulate the joints 8 to protect them from oxidation and / or cooling media. The respective slot insulation 15 can have a collar 15 for axial support on the stator body 3. The expandable slot insulations 15 can also achieve a subsequent frictional connection of the joints.

[0053] Fig.5A shows two joining sections of a joining pair of conductor elements belonging to different winding parts in the state before joining.

[0054] To form the joining pairs 11, for example, two different joining sections 12.1, 12.2 are provided and formed on the two winding parts 6.1, 6.2.

[0055] A first joining section 12.1 of the respective joining pair 11 additionally has a guide 23 which leads the locking hook 17 of the first joining section 12.1 in the joining direction and whose conductor width b is in particular smaller than the conductor width b of the remaining part of the first joining section 12.

[0056] A second joining section 12.2 of the same joining pair 11 additionally has a counter-guide 24, which trails the locking recess 18 of the second joining section 12.2 in the joining direction, for guiding the leading guide 23 of the first joining section 12.1, the conductor width b of which is in particular greater than the conductor width b of the remaining part of the second joining section 12.2. At the first joining section 12.1, the transition from the locking recess 18 to the full conductor cross-section of the conductor element 10 is designed as a step.

[0057] At the second joining section 12.2, the transition from the locking recess 18 to the counter-guide 24 and the transition from the counter-guide 24 to the full conductor cross-section of the conductor element 10 is designed as a step.

[0058] The opposing joining surfaces 14 of the respective joining pair 11 have two corresponding pressing sections 16. In the case of a snap-in connection, the pressing sections 16 are formed, for example, on the snap-in hooks 17.

[0059] The respective pressing section 16 of the respective joining pair 11 can run outside the inlet area 17f parallel to the axial direction or with a pressure increasing in the joining direction at an oblique angle to the axial direction.

[0060] Fig.5B shows the two joining sections of the joining pair according to Fig.5A in the state of sliding of the pressing sections on each other during joining.

[0061] The two corresponding pressing sections 16 are clamped when sliding against each other due to an excess between the tooth flanks 4f, which results in increased sliding friction between the pressing sections 16 and, as a result, a plastic deformation of the joining surfaces 14, in particular in the pressing sections 16.

[0062] The pressing sections 16 of the joining surfaces 14 are thus plastically deformed after joining. This creates a small air gap between the joining surfaces 14 or reduces the air gap.

[0063] Fig.5C shows the two joining sections of the joining pair according to Fig.5A in the state after joining.

[0064] At least one joining surface 14 of the respective joining pair can be coated, for example with a solder, to reduce the contact resistance, to activate the surface or to create a material bond.

Claims

Claims 1. Stator of an electrical machine (2) with a stator body (3), in particular a stator laminated core, which has stator teeth (4) and stator slots (5) formed between the stator teeth (4), wherein the stator slots (5) are each formed between tooth flanks (4f) of adjacent stator teeth (4), wherein an electrical stator winding (6) runs through the stator slots (5), wherein the stator winding (6) has two separate winding parts (6.1, 6.2) which are joined to one another in an axial joining direction with respect to a stator axis (7) to form joining connections (8) and each comprise a plurality of conductor elements (10), in particular U-shaped hairpins, wherein each of the joining connections (8) has a joining pair (11) of winding parts (6.1, 6.2), wherein the conductor elements (10) of the respective joining pair (11) have joining sections (12) at the mutually facing conductor ends, on each of which joining sections there is a joining recess (13) for receiving the respective other joining section (12) and, due to the joining recess (13), a reduced conductor cross-section is provided, wherein the joining sections (12) of the respective joining pair (11) have joining surfaces (14) along their joining recess (13), which face one another and have a longitudinal extension in the axial direction, characterized in that the joining surfaces (14) of the joining pairs (11) each face one of the tooth flanks (4f) of the respective stator slot (5).

2. Stator according to claim 1, characterized in that the joining surfaces (14) of the joining pairs (11) are each designed in such a way that during joining an at least partial plastic deformation of the joining surfaces (14) can be produced with support on the respective tooth flanks (4f).

3. Stator according to one of the preceding claims, characterized in that the conductor cross-sections of the conductor elements (10) have a conductor width (b) which extends in the circumferential direction between the tooth flanks (4f) and a conductor height (h) which extends in the radial direction with respect to the stator axis (7), wherein in order to form the reduced conductor cross-sections of the joining sections (12), the conductor width (b) of the joining sections (12) is reduced in each case over the full conductor height (h) of the joining section (12).

4. Stator according to one of the preceding claims, characterized in that the joining surfaces (14) of the respective joining pair (11) have two corresponding pressing sections (16) which, when sliding against one another, are clamped due to an excess between the tooth flanks (4f), whereby an increased sliding friction is established between the pressing sections (16) to produce the plastic deformation of the joining surfaces (14).

5. Stator according to claim 4, characterized in that the pressing sections (16) of the joining surfaces (14) are plastically deformed, in particular to reduce an air gap formed between the joining surfaces (14).

6. Stator according to one of the preceding claims, characterized in that in each of the stator slots (5) a slot insulation (15), in particular an insulating paper or insulating laminate, is provided, which is in particular expandable for encapsulating the joints (8) for protection against oxidation and / or for protection against cooling media and / or in particular has a collar (15k) for axial support on the stator body (3).

7. Stator according to one of claims 4 to 6, characterized in that the joining sections (12) of each joining pair (11) form a latching connection (8), wherein each joining section (12) has on its joining surface (14) a latching hook (17) leading in the joining direction and a trailing latching recess (18), wherein the pressing sections (16) are formed in particular on the latching hooks (17).

8. Stator according to claim 7, characterized in that to form the joining pairs (11) two different joining sections (12) are provided and are formed on the two winding parts (6.1, 6.2), wherein - a first joining section (12.1) of the respective joining pair (11) additionally has a guide (23) which leads the locking hook (17) of the first joining section (12.1) in the joining direction and whose conductor width (b) is in particular smaller than the conductor width (b) of the remaining part of the first joining section (12.1) and - a second joining section (12.2) of the same joining pair (11) additionally comprises one of the Locking recess (18) of the second joining section (12.2) in the joining direction trailing counter-guide (24) for guiding the leading guide (23) of the first joining section (12.1), the conductor width (b) of which is in particular greater than the conductor width (b) of the remaining part of the second joining section (12.2).

9. Stator according to one of claims 7 or 8, characterized in that the locking hooks (17) each have an inlet region (17f), in particular a chamfer, bevel, curvature or rounding.

10. Stator according to one of the preceding claims, characterized in that the joined joining sections (12) of the respective joining pair (11) together form a full conductor cross-section.

11. Stator according to one of the preceding claims, characterized in that adjacent joining connections (8) located in the same stator groove (5) are offset from one another in the axial direction.

12. Stator according to one of the preceding claims, characterized in that at least one joining surface (14) of the respective joining pair (11) is coated to reduce the contact resistance, to activate the surface or to create a material bond.

13. Electrical machine (2) with a stator (1) according to one of the preceding claims.