Stator for an electric machine and traction drive
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-02-03
- Publication Date
- 2026-08-13
Smart Images
Figure DE2026100125_13082026_PF_FP_ABST
Abstract
Description
[0001] 202401362
[0002] 1
[0003] Description
[0004] Stator for an electric machine and traction drive
[0005] The invention relates to a stator for an electric machine with a flat conductor element. A further aspect of the invention is a traction drive with the stator according to the invention.
[0006] Flat conductor elements for electrical machines are generally known.
[0007] For example, DE 102015216840 A1 discloses a stator with an insulated bar winding for an electric machine. According to this patent, the bar winding comprises a plurality of bars, each bar having an electrical insulation element and a stripped end. A transition or cut edge between the insulation element and the stripped end is straight or formed at an angle of 90 degrees to the longitudinal extent of the bar element.
[0008] It has been shown that in stators with a reduced slot spacing in the circumferential direction, the leakage current between two bar windings spaced apart in the circumferential direction of the stator can be increased.
[0009] A first object of the invention is to provide a stator for an electric machine in which a leakage current between two flat conductor elements of a stator winding can be reduced, and wherein the stator can have a reduced winding head height.
[0010] A second object of the invention is to provide a traction drive for a motor vehicle in which a leakage current of a stator winding can be reduced and which can have a reduced installation space.
[0011] The first problem is solved by independent claim 1. The second problem is solved by dependent claim 11.
[0012] Preferred embodiments of the invention are the subject of the dependent claims, the following description and the drawings, wherein 202401362
[0013] 2
[0014] Each feature can represent an aspect of the invention, both individually and in combination, unless explicitly stated otherwise in the description.
[0015] In a first aspect, the invention relates to a stator for an electric motor vehicle, comprising an annular stator yoke with a plurality of slots spaced apart from one another in the circumferential direction of the stator yoke, a plurality of flat conductor elements formed to form a stator winding and connected to one another, wherein an end section of the flat conductor elements is guided over an end face of the stator yoke and twisted in the circumferential direction of the stator, so that the contact sections of two flat conductor elements arranged in different slots are formed next to each other in the radial direction of the stator and the contact sections are electrically connected to one another, wherein the flat conductor elements to be connected each comprise an electrical conductor having an outer surface, wherein an electrical insulating layer is formed on the outer surface.the electrical conductor has a contact section, wherein the contact section is designed without an insulating layer, and the insulating layer has a cut edge at a transition to the contact section, wherein the cut edge is chamfered section by section with respect to a longitudinal extent of the flat conductor element, and the contact sections of two flat conductor elements to be connected are arranged in the zero gap and thus gap-free to each other and are connected to each other.
[0016] In other words, according to the second aspect of the invention, a stator is provided which has a plurality of flat conductor elements arranged in slots of a stator yoke. The stator yoke is preferably annular in shape, with the slots of the stator yoke preferably being formed on an inner surface oriented radially to the stator and extending between two end faces spaced apart from each other axially to the stator. An end section of the flat conductor elements is guided over one of the end faces of the stator yoke and in a circumferential direction.
[0017] 3
[0018] The stator is twisted. The contact sections of two twisted flat conductor elements are arranged and positioned so that they are located next to each other in the radial direction of the stator. Furthermore, the contact sections of the two flat conductor elements are electrically connected to each other. The flat conductor element comprises an electrical conductor, the electrical conductor comprising an outer cladding surface. The electrical conductor preferably comprises copper and / or aluminum. It is conceivable that the electrical conductor is designed as a bimetallic material. An electrical insulating layer is formed on the outer cladding surface of the electrical conductor. The electrical insulating layer is a non-conductive layer or non-conductive coating, which may preferably be formed in one or more layers. The electrical conductor also comprises a contact section. The contact section is designed without an insulating layer.At the transition from the insulation layer to the contact section, the insulation layer has a cut edge. This cut edge is chamfered in sections relative to the longitudinal extent of the flat conductor element or the electrical conductor. In other words, the cut edge of the insulation layer in the chamfered section does not run at an angle of 90° to the longitudinal extent of the flat conductor element, as is known from the prior art. The chamfered cut edge of the insulation layer at the contact section increases the electrical insulation, particularly the creepage distance, between two flat conductor elements arranged circumferentially in a stator, thus reducing or preventing leakage current between circumferentially adjacent flat conductor elements, especially the contact sections. In other words, the use of flat conductor elements can reduce the path or...The distance of the electrical insulation of two circumferentially adjacent and not directly connected flat conductor elements can be increased, thereby increasing the creepage distance or reducing or avoiding leakage currents.
[0019] According to the invention, the contact sections of two flat conductor elements to be connected are located in a zero gap and are therefore gap-free towards each other.
[0020] 4
[0021] The components are arranged and interconnected. This is made possible in particular by the chamfered cut edge. The zero gap reduces the energy input required for the metallurgical bonding, especially during welding, of the contact sections. This reduced energy input also reduces the risk of the insulation layer burning during the welding process. Furthermore, the reduced energy input allows for a reduction in the axial end section, if present, as the distance between the distal end and the cut edge can be reduced. This reduced axial end section results in a reduced stator winding head height. This saving in the height of the stator winding head can, in turn, lead to a reduction in the axial length of the stator.On the other hand, the saved axial installation space can also be used to lengthen the active part of the stator accordingly, in order to increase the performance of the traction drive.
[0022] An advantageous embodiment of the invention lies in the fact that the following angles apply to the angle α of the beveled cut edge relative to the longitudinal extent of the flat conductor element: 45° < α < 87°, preferably 50° < α < 85°, and particularly preferably 55° < α < 80°. The smaller the angle α, the steeper the cut edge is oriented relative to the longitudinal extent of the flat conductor element. The larger the angle α, the more obtuse the cut edge is oriented relative to the longitudinal extent of the flat conductor element. Depending on the design of a winding head of the stator winding, different angles of cut edges can be advantageous for increasing the creepage distance between two flat conductor elements.
[0023] In an advantageous embodiment of the invention, the flat conductor element has a rectangular cross-section with two first sides and two second sides, wherein the chamfered cut edge is formed exclusively on the second sides. On the first sides, the cut edge runs at an angle of 90° to the longitudinal extent of the flat conductor element, but preferably offset from each other. 202401362
[0024] 5
[0025] In this context, a preferred embodiment of the invention consists in the length of the second side being greater than the length of the first side. The lengths of the first and second sides are each measured at an angle of 90° to the longitudinal extent of the flat conductor element. It is therefore conceivable that the flat conductor element has a cross-section with a strong and a weak axis. The second sides of the flat conductor element are aligned parallel to the weak axis, and the cut edge on these sides is chamfered accordingly. The first sides run parallel to the strong axis and have a cut edge that is formed at an angle of 90° to the longitudinal extent of the flat conductor element and is also preferably offset from one another.
[0026] It is conceivable, and not excluded, that the chamfered cut edge extends only partially on the second side. In other words, the cut edge on the second side can be chamfered in a first section and run at a 90° angle to the longitudinal extent of the flat conductor element in a second section adjacent to the first. Depending on the design of the stator winding head, this can have an advantageous effect on the creepage distance between two adjacent contact sections.
[0027] Advantageously, the section of the cut edge on the second side, which is aligned at a 90° angle to the longitudinal extent, faces an end face of the stator after a twist of the end section. The beveled cut edge is therefore directed away from the end face of the stator or towards the free end of the flat conductor element.
[0028] It is also conceivable, and not excluded, that the cut edge on the second side is chamfered at two different angles. It is therefore imaginable that the cut edge has an inclined first section with a first angle ai and a second inclined section, preferably directly adjacent to the first section, with a second angle 02, where ai is different from 02.
[0029] 6
[0030] It is advantageous in this context that 02 > ai. The angle ranges of a described above apply to ai and 02.
[0031] Preferably, the respective cut edge is formed identically on the second sides.
[0032] According to an advantageous embodiment of the invention, the beveled cut edge extends over the entire length of the second side. In other words, the beveled cut edge on the second side runs between the two first sides of the flat conductor element, preferably at the same angle a.
[0033] A preferred embodiment of the invention is characterized in that a distal end of the flat conductor element is formed in an arc or parabolic shape. Such a distal end of the flat conductor element or contact section is advantageously suited for a stator winding in which the flat conductor elements are designed as so-called X-pins. The stator winding preferably has no axial end section. In a stator winding designed as an X-pin, the flat conductor elements are preferably bonded together at the intersection point of two flat conductor elements or contact sections, particularly in the arc or parabolic region. The absence of the axial end section allows the axial length of the stator to be reduced.
[0034] The insulating layer can be designed to have electrically insulating properties. An advantageous embodiment of the invention is that the insulating layer comprises a plastic and / or a resin. The insulating layer can also be referred to as an insulating varnish. Preferably, the plastic comprises a polyamide-imide (PAI), an aromatic polyimide (PI), or polyetheretherketone (PEEK).
[0035] 7
[0036] In principle, the insulating layer can be a single layer. Such a flat conductor element is easy and inexpensive to manufacture.
[0037] Alternatively, the insulating layer could be multi-layered, with the elasticity of the insulating layer increasing with increasing distance from the outer surface of the electrical conductor. This would allow the insulating layer to absorb increased strain in the bending area, reducing damage to the insulating layer during the formation of a winding head, which can be advantageous in preventing leakage currents.
[0038] The flat conductor element can advantageously be configured as an I-pin. It is conceivable, and not excluded, that the flat conductor element could be configured as a hairpin. Another possible embodiment provides for the flat conductor element to be configured as an X-pin. A stator can preferably incorporate a combination of differently configured flat conductor elements. Thus, it is conceivable, and not excluded, that some flat conductor elements could be configured as hairpins and others as I-pins.
[0039] An advantageous further development of the invention lies in the fact that the flat conductor element has a rectangular cross-section with two first sides and two second sides, wherein
[0040] The chamfered cut edge is formed exclusively on the second sides, and the insulation layer on the first side, facing the end face of the stator yoke, is shorter than the insulation layer on the first side, facing away from the end face of the stator yoke. Thus, for both stator windings with an X-pin winding head and stator windings with a classic axial end section, the cut edge can be chamfered and shaped in such a way that the electrical insulation to the circumferentially adjacent flat conductor element is increased, thereby minimizing or preventing leakage currents. 202401362
[0041] 8
[0042] In an advantageous embodiment of the invention, a distal end of the flat conductor elements is formed in an arc or parabolic shape, and this distal end is located at the intersection point of the interconnected flat conductor elements. In this way, the flat conductor elements can preferably be configured as an X-pin winding, thereby reducing the axial height of the winding head and thus also of the entire stator. The arc or parabolic shape of the distal end also allows the same flat conductor elements, or the same lengths, to be used for the various layers of the flat conductor winding in the radial direction of the stator. The arc shape of the conductor end enables corresponding compensation of the lengths with respect to the different bending or twisting radii. This reduces the number of parts required, which can have a beneficial effect on the cost of the stator.
[0043] Alternatively, the flat conductor element is twisted in such a way that the contact section forms an end section extending in the axial direction of the stator. This can have an advantageous effect on the twisting process, particularly in selective twisting, where the distance between the conductor ends of individual flat conductor elements can vary in the circumferential direction.
[0044] In a second aspect, the invention relates to a traction drive for a motor vehicle with the stator according to the invention.
[0045] It should be noted that all features described above and below with respect to one aspect of the present invention apply equally to every other aspect of the present invention. In particular, all features of the flat conductor element can apply equally to the stator and / or the traction drive. The reverse is also true.
[0046] Further features and advantages of the present invention will become apparent from the dependent claims and the following exemplary embodiments. 202401362
[0047] 9
[0048] The exemplary embodiments are not limiting but rather intended to be illustrative. They are meant to enable a person skilled in the art to carry out the invention. The applicant reserves the right to make one or more of the features disclosed in the exemplary embodiments the subject of patent claims or to include such features in existing patent claims. The exemplary embodiments are explained in more detail with reference to the drawings.
[0049] These show:
[0050] Fig. 1 shows a section of a stator winding according to the prior art, Fig. 2 shows a flat conductor element designed as a hairpin according to the prior art,
[0051] Fig. 3 shows a section of a stator winding of a stator according to a first embodiment,
[0052] Fig. 4 shows a flat conductor element designed as a hairpin according to the first embodiment,
[0053] Fig. 5 shows a section of the stator winding of the stator according to a second embodiment,
[0054] Fig. 6 shows the flat conductor element designed as a hairpin according to the second embodiment.
[0055] Figure 1 shows a section of a stator winding SW of a stator ST according to the prior art, wherein the stator winding SW is formed with a flat conductor element FE configured as a hairpin. The flat conductor element FE is shown in Figure 2. Reference is made to Figures 1 and 2 simultaneously below.
[0056] The stator winding SW has a plurality of flat conductor elements FE, which are arranged in slots (not shown) in a circumferential direction of the stator ST. The flat conductor elements FE have an electrical conductor EL. The electrical conductor EL comprises an outer cladding surface AM, on which an insulating layer IS is applied. Furthermore, 202401362
[0057] 10
[0058] It is evident that a contact section KA is formed at one end of the flat conductor element FE, which has no insulating layer IS. The insulating layer IS has a straight cut edge SK at the transition to the contact section KA. In other words, the cut edge SK runs at an angle of 90° to a longitudinal extension LE of the flat conductor element FE.
[0059] The flat conductor elements FE have end sections EA that are guided over an end face aligned in an axial direction of a stator yoke of the stator ST and are twisted in the circumferential direction of the stator ST, wherein the contact sections KA of two radially adjacent end sections EA of different flat conductor elements FE are connected to each other. In the known design of a winding head of the stator winding SW, a creepage distance KS between two contact sections KA adjacent to each other in the circumferential direction of the stator ST can be reduced.
[0060] Fig. 3 shows a section of a stator winding SW of a stator ST according to a first embodiment. A corresponding flat conductor element FE for forming the stator winding SW is shown in Fig. 4. Reference is made to Figs. 3 and 4 simultaneously below.
[0061] The flat conductor element FE is configured as a hairpin and has an electrical conductor EL. The electrical conductor EL comprises an outer cladding surface AM, on which an electrical insulating layer IS is formed. The electrical conductor EL has a contact section KA, which is free of an insulating layer. A cut edge SK is formed at a transition between the insulating layer IS and the contact section KA, and the cut edge SK is chamfered at least partially with respect to a longitudinal extent LE of the flat conductor element FE. In other words, the flat conductor element FE in Fig. 4 differs from the flat conductor element FE shown in Fig. 2, among other things, in the design and / or inclination of the cut edge SK.
[0062] 11
[0063] The flat conductor element FE has a rectangular cross-section perpendicular to its longitudinal extent LE, with two first sides S1 and two second sides S2. The chamfered cut edge SK is formed exclusively on the second sides S2 of the flat conductor element FE. On the first sides S1 of the flat conductor element FE, the cut edge SK is formed at a right angle to the longitudinal extent LE of the flat conductor element FE. Due to the chamfered cut edge SK on the second sides S2, the cut edges SK on the first sides S1 are offset from each other. The cut edge SK on the second side S2 is inclined at an angle α of 60° to the longitudinal extent LE of the flat conductor element FE. The inclined cut edge SK extends between the two first sides S1 of the flat conductor element FE.
[0064] As can be seen in Fig. 3, a plurality of flat conductor elements FE are formed into a winding head of a stator winding SW of the stator ST. The end sections EA of the flat conductor elements FE extend beyond the end face of a stator yoke of the stator ST and are twisted circumferentially, with a distal end section of the flat conductor elements FE, which is also the respective contact section KA, oriented axially to the stator ST. The insulation layer IS is shorter on the first side S1, which faces the end face of the stator yoke, than the insulation layer IS on the first side S1, which faces away from the end face of the stator yoke. In other words, the insulation layer IS on the first side S1, which faces the free end of the flat conductor element FE, is longer than the insulation layer IS on the first side S1, which faces away from the free end of the flat conductor element FE.
[0065] The chamfered cutting edge SK allows the creepage distance between two circumferentially adjacent contact sections KA to be extended, thus minimizing or preventing creepage currents between two contact sections KA. 202401362
[0066] 12
[0067] Fig. 5 shows a section of the stator winding SW of the stator ST according to a second embodiment. Fig. 6 shows the flat conductor element FE, configured as a hairpin, for the stator winding SW according to the second embodiment. Reference is made to Figs. 5 and 6 simultaneously below.
[0068] The flat conductor element FE according to the second embodiment is a hairpin, wherein a distal end of the flat conductor element FE is arcuate or parabolic. Such a distal end of the flat conductor element FE, or of the contact section KA, is advantageously suited for a stator winding SW in which the flat conductor elements FE are configured as so-called X-pins. The stator winding SW preferably has no axial end section with respect to the longitudinal extent of the stator ST (Fig. 5). In a stator winding SW configured as an X-pin, the flat conductor elements FE are preferably bonded together at the intersection of two flat conductor elements FE by a material bond, particularly in the arcuate or parabolic region. The material bond and electrically conductive connection is preferably a weld. Due to the absence of the axial end section, the axial length of the stator ST can be reduced.
[0069] The arc-shaped or parabolic design of the distal end of the flat conductor element FE also means that the same flat conductor elements FE, or rather the same lengths, can be used for the various layers of the stator winding SW in the radial direction of the stator ST. The arc shape of the conductor end allows for corresponding compensation of the lengths with respect to the different radii. This reduces the number of different flat conductor elements FE required, which can have a beneficial effect on the cost of the stator.
[0070] By means of the chamfered cutting edge SK, in analogy to the first embodiment, the creepage distance between two circumferentially adjacent 202401362
[0071] 13
[0072] The contact section KA can be extended so that leakage currents between two contact sections KA can be minimized or avoided.
Claims
202401362 14 Patent claims 1. Stator (ST) for an electric machine of a motor vehicle, comprising a circularly shaped stator yoke with a plurality of slots spaced apart from each other in the circumferential direction of the stator yoke, a plurality of flat conductor elements (FE) formed into a stator winding (SW) and connected to each other, wherein an end section of the flat conductor elements (FE) is guided over an end face of the stator yoke and twisted in the circumferential direction of the stator (ST), so that the contact sections (KA) of two flat conductor elements (FE) arranged in different slots are formed next to each other in the radial direction of the stator (ST), and the contact sections (KA) are electrically connected to each other, wherein The flat conductor elements (FE) to be joined each comprise an electrical conductor (EL) having an outer cladding surface (AM) with an electrical insulating layer (IS) on the outer cladding surface (AM), the electrical conductor (EL) having a contact section (KA) having a contact section (KA) without an insulating layer, and the insulating layer (IS) having a cut edge (SK) at a transition to the contact section (KA), the cut edge (SK) being chamfered section by section with respect to a longitudinal extent (LE) of the flat conductor element (FE), and the contact sections (KA) of two flat conductor elements (FE) to be joined are arranged in the zero gap and thus without gaps to each other and are connected to each other.
2. Stator (ST) according to claim 1 , characterized in that for an angle a of the chamfered cutting edge (SK) the following applies: 45° < a < 87°.
3. Stator (ST) according to claim 1 or 2, characterized in that the flat conductor element (FE) has a rectangular cross-section with two first sides (S1) and two second sides (S2), wherein the chamfered cut edge (SK) is formed exclusively on the second sides (S2), and the insulating layer (IS) on the first side (S1), which the202401362 15 the end face of the stator yoke is shorter than the insulation layer (IS) on the first side (S1) which faces away from the end face of the stator yoke.
4. Stator (ST) according to claim 3, characterized in that the length of the second side (S2) is greater than the length of the first side (S1).
5. Stator (ST) according to claim 3 or 4, characterized in that the chamfered cutting edge (SK) extends over the entire length of the second side (S2).
6. Stator (ST) according to one of the preceding claims, characterized in that the insulation layer (IS) comprises a plastic and / or resin.
7. Stator (ST) according to one of the preceding claims, characterized in that the insulating layer (IS) is formed in multiple layers, wherein the elasticity of the insulating layer (IS) increases with increasing distance to the outer cladding surface (AM) of the electrical conductor (EL).
8. Stator (ST) according to one of the preceding claims, characterized in that the flat conductor element (FE) is an I-pin, a hairpin or an X-pin.
9. Stator (ST) according to one of the preceding claims, characterized in that a distal end of the flat conductor elements (FE) is arc-shaped or parabolic, and the distal end is formed at a crossing point of the interconnected flat conductor elements (FE).
10. Stator (ST) according to one of the preceding claims, characterized in that the flat conductor element (FE) is twisted such that the contacting section (KA) forms an end section extending in the axial direction of the stator (ST).
11. Traction drive for a motor vehicle with a stator (ST) according to one of claims 1 to 10.