Insulation ring, stator and method for producing a stator

Abstract

The invention relates to an insulation ring (1) for a winding head (2) of a hairpin winding (3) of a stator (4) of an electrical machine (5) within a drivetrain (15) of a motor vehicle (16), wherein the insulation ring (1) comprises an annular disc-shaped main body (6) with a plurality of openings (7) that extend axially through the main body (6) and can each be penetrated at least in sections by the free ends (8) of a pair of hairpin conductor rods (9), wherein at least one spacer element (10) protrudes out of the main body (6) in a first axial direction and at least one retaining element (12) protrudes out of the main body (6) in a second axial direction.

Description

[0001] Insulation ring, stator and method for producing a stator

[0002] The present invention relates to an insulating ring for a winding head of a hairpin winding of a stator of an electrical machine within a drive train of a motor vehicle. The insulating ring comprises an annular disk-shaped base body with a plurality of openings extending axially through the base body, each of which can be penetrated at least partially by the free ends of a hairpin conductor bar pair. The invention further relates to a stator and a method for producing a stator.

[0003] Electric motors are increasingly being used to power motor vehicles, creating alternatives to combustion engines that require fossil fuels. Considerable efforts have already been made to improve the everyday suitability of electric drives and also to provide users with the same level of driving comfort they are accustomed to.

[0004] A detailed description of an electric drive can be found in an article in the magazine ATZ, Volume 63, May 2020, pages 360-365, by Erik Schneider, Frank Fickl, Bernd Cebulski, and Jens Liebold, entitled: "Highly Integrative and Flexible Electric Drive Unit for E-Vehicles." This article describes a drive unit for one axle of a vehicle. This drive unit comprises an electric motor arranged concentrically and coaxially with a bevel gear differential. In the power train between the electric motor and the bevel gear differential, a switchable 2-speed planetary gear set is arranged, which is also positioned coaxially with the electric motor or the bevel gear differential or spur gear differential. The drive unit is very compact and, thanks to the switchable 2-speed planetary gear set, allows a good compromise between gradeability, acceleration, and energy consumption. Such drive units are also referred to as e-axles.

[0005] In addition to purely electric drivetrains, hybrid drivetrains are also known. Such drivetrains in hybrid vehicles typically comprise a combination of an internal combustion engine and an electric motor, enabling purely electric operation—for example, in urban areas—while maintaining sufficient range and availability, especially for long-distance journeys. Furthermore, in certain operating situations, it is possible to use both the internal combustion engine and the electric motor simultaneously.

[0006] For the development of electrical machines, in particular electrical machines for the above-mentioned hybrid or fully electric motor vehicles or also for wheel hub drives, basically different winding technologies for a stator of an electrical machine are known.

[0007] Electrical machines with a hollow-cylindrical stator, i.e., internal rotor machines, and configured for use as traction drives in motor vehicles often have a stator winding with a rectangular cross-section to achieve high power density. In electrical machines intended for motor vehicle power, the stator windings are therefore typically designed as hairpin windings. In this case, for example, essentially U-shaped wire segments are inserted into the stator slots from one end face of the stator and then formed on an opposite end face of the stator and connected, for example, by welding.

[0008] For such hairpin windings, it is also known to electrically insulate them, along with the winding head of the hairpin winding, by means of a so-called full potting of the stator. However, this carries the risk of cracking in the potting over the service life of the stator due to vibration loads during operation of the electrical machine. These cracks can then lead to the formation of air and creepage distances and local electrical short circuits, which can have a negative impact on the performance of the electrical machine and is often undesirable.

[0009] As an alternative or in addition to full encapsulation, closed caps for insulating the hairpin ends on a winding head of a hairpin winding are also known from the prior art. An example of this is disclosed in JP2000209802A.

[0010] It is therefore the object of the invention to provide an insulation ring for a winding overhang of a hairpin winding of a stator of an electrical machine within a drive train of a motor vehicle, which insulation ring allows reliable and long-lasting insulation of the winding overhang, which insulation ring is cost-effective to manufacture and easy to install. It is also the object of the invention to realize a stator for an electrical machine within a drive train of a motor vehicle, which stator has reliable and long-lasting insulation of a winding overhang of a hairpin winding. It is furthermore the object of the invention to specify a method for producing a stator for an electrical machine within a drive train of a motor vehicle, by means of which method reliable and long-lasting insulation of a winding overhang can be realized.

[0011] This object is achieved by an insulation ring for a winding head of a hairpin winding of a stator of an electrical machine within a drive train of a motor vehicle, wherein the insulation ring has an annular disk-shaped base body with a plurality of openings extending axially through the base body, each of which openings can be penetrated at least partially by the free ends of a hairpin conductor bar pair, wherein at least one spacer element extends out of the base body in a first axial direction and at least one holding element extends out of the base body in a second axial direction.

[0012] This provides the advantage that the insulation ring can be easily placed axially onto a stator, with the axial distance between the stator and the base body being defined by the at least one spacer element. In other words, the at least one spacer element forms an axial stop for the insulation ring relative to the stator. The insulation ring can be held by means of the at least one holding element, for example, using a suitable tool, and placed onto the winding head of the hairpin winding. First, the individual elements of the claimed subject matter of the invention are explained in the order in which they appear in the claims, followed by a description of particularly preferred embodiments of the subject matter of the invention.

[0013] The stator according to the invention is intended for use in an electrical machine. The electrical machine serves to convert electrical energy into mechanical energy and / or vice versa, and it generally comprises the stationary part referred to as the stator, stand, or armature, and a part referred to as the rotor or runner, which is arranged so as to be movable, in particular rotatable, relative to the stationary part. In particular, the electrical machine is dimensioned such that vehicle speeds greater than 50 km / h, preferably greater than 80 km / h, and in particular greater than 100 km / h, can be achieved. The electric motor particularly preferably has an output greater than 30 kW, preferably greater than 50 kW, and in particular greater than 70 kW. It is further preferred that the electrical machine provides speeds greater than 5,000 rpm, particularly preferably greater than 10,000 rpm, and most particularly preferably greater than 12,500 rpm.

[0014] The stator can, in particular, be supplied with current by power electronics. The power electronics are preferably a combination of various components that control or regulate a current to the stator, preferably including the peripheral components required for this purpose, such as cooling elements or power supplies. In particular, the power electronics contains one or more power electronics components designed to control or regulate a current. These are particularly preferably one or more power switches, e.g., power transistors. The power electronics particularly preferably has more than two, particularly preferably three, separate phases or current paths, each with at least one dedicated power electronics component.

[0015] The power electronics are preferably designed to control or regulate a power per phase with a peak power, preferably continuous power, of at least 10 W, preferably at least 100 W, particularly preferably at least 1000 W. The power electronics are preferably connected to the stator winding of the stator via an HV terminal (HV = high voltage).

[0016] For the purposes of this application, motor vehicles are defined as land vehicles that are propelled by mechanical power without being tied to railway tracks. A motor vehicle can, for example, be selected from the group of passenger cars (PCs), trucks (HGVs), mopeds, light motor vehicles, motorcycles, buses (KOMs), or tractors.

[0017] The stator according to the invention can preferably be configured for a radial flux machine. The stator of a radial flux machine is usually cylindrical or cylindrically ring-shaped and generally consists of a stator body formed by electrically insulated, layered, and stacked laminations in laminated cores. This structure minimizes the eddy currents in the stator caused by the stator field. Distributed around the circumference, stator slots are recessed into the electrical core, running parallel to the rotor shaft, and accommodate the stator winding or parts of the stator winding. Depending on the design, the slots can be closed with closure elements, such as closure wedges, covers, or the like, to prevent the stator winding from becoming detached.

[0018] The stator body is preferably formed as a single piece. A single-piece stator body is characterized by the fact that the entire stator body is formed as a single piece across its circumference. The stator body is typically formed from a plurality of stacked laminated electrical sheets, each of which is formed into a closed circular ring. The individual sheets can be held together in the stator body, for example, by gluing, welding, or screwing.

[0019] The stator teeth of the stator are preferably formed in the stator body. Stator teeth are components of the stator body that are designed as circumferentially spaced, tooth-like parts of the stator body that are directed radially inward (inner rotor) or radially outward (outer rotor). Between their free ends and a rotor body, an air gap is formed for the magnetic field and for the rotational movement of the rotor. The air gap is the non-magnetic gap existing between the rotor and the stator. In a radial flux machine, for example, this is an essentially circular gap with a radial width that corresponds to the distance between the rotor body and the stator body.

[0020] A stator winding is embedded in the stator slots of the stator according to the invention. A stator winding comprises electrically conductive conductors whose length is significantly greater than their diameter. The stator winding can, in principle, have any cross-sectional shape. Rectangular cross-sectional shapes are preferred, as these allow high packing and, consequently, power densities to be achieved. A stator winding is particularly preferably made of copper. According to the invention, the stator winding is designed as a hairpin winding.

[0021] The insulating ring is preferably made of a material that is electrically non-conductive or at least only weakly conductive. The insulating ring can be made of a ceramic or a plastic, for example. The plastic is preferably a fiber-reinforced plastic. Most preferably, the insulating ring is formed from a plastic using an injection molding process.

[0022] The openings of the insulation ring are preferably arranged along concentrically extending diameters in the annular disk-shaped base body. Furthermore, the openings are preferably positioned equidistant from one another on a diameter. In this context, it is further preferable that the openings are positioned on the concentrically extending diameters in circumferentially distributed groups of openings arranged radially aligned with one another. In this regard, it is also highly preferred that radially aligned openings of a group are spaced equidistant from one another. It is also highly preferred that the openings are essentially identical in shape. In this case, it may be preferred for an opening to be essentially rectangular in shape with rounded corners and for its longitudinal extent to be oriented in the circumferential direction of the insulation ring.

[0023] The insulation ring can be formed in one piece or in multiple parts. Preferably, the base body of the insulation ring is formed in one piece, more preferably monolithic. However, it would also be possible for the insulation ring to be formed from several ring segments that are connected to one another by a material fit, a force fit, and / or a form fit.

[0024] It may further be preferred that the at least one spacer element be formed integrally, preferably monolithically, with the base body. In principle, it would also be conceivable for the spacer element to be formed from a material different from that of the base body. It would also be possible to design the spacer element as a separate component from the base body that is connected to the base body in a form-fitting, force-fitting, and / or material-fitting manner.

[0025] The retaining element can preferably be formed integrally, in particular monolithically, with the base body of the insulation ring. In principle, it would also be conceivable for the retaining element to be formed from a material different from that of the base body. It would also be possible to design the retaining element as a separate component from the base body, which is connected to the base body in a form-fitting, force-fitting, and / or material-fitting manner.

[0026] According to an advantageous embodiment of the invention, it can be provided that the insulation ring has at least three spacer elements and / or at least three holding elements. The advantage of this embodiment is that it can provide statically determined supports or contacts that prevent unintentional tilting of the insulation ring, for example on the end face of the stator. According to a further preferred development of the invention, it can also be provided that the spacer elements and / or the holding elements are arranged equidistantly along the circumference of the insulation ring, which further increases the tilt resistance of the insulation ring. The at least three spacer elements can be designed as webs. The spacer elements are preferably designed in the manner of an annular shell segment. Furthermore, the spacer elements are preferably arranged on the radially outer diameter of the annular disk-like base body.It may also be preferable for the spacer elements to extend trapezoidally in the axial direction, with the long trapezoidal side facing the base body and the short trapezoidal side facing the stator. Most preferably, the at least three spacer elements are formed from the same part. According to a further, highly preferred embodiment of the invention, the insulation ring has exactly three spacer elements. All of these measures can support the lightweight construction of the electrical machine in that the spacer elements are designed solely for the axial positioning of the insulation ring relative to the stator.

[0027] The at least three retaining elements can be designed as webs. The webs are preferably cylindrical. Furthermore, the retaining elements are preferably arranged on the radially outer diameter of the annular disk-like base body. Most preferably, the at least three retaining elements are formed from the same part. According to a further, highly preferred embodiment of the invention, the insulating ring has exactly three retaining elements. All of these measures can support the lightweight construction of the electrical machine in that the retaining elements are designed solely for the axial and circumferential positioning of the insulating ring relative to a tool.

[0028] Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that the spacer elements and the holding elements each form pairs associated with one another, which are each positioned in a common circumferential segment of the insulation ring.

[0029] The object of the invention is further achieved by a stator for an electrical machine within a drive train of a motor vehicle, wherein the stator is designed in the shape of a cylindrical ring and a winding head of a hairpin winding extends axially out of the stator on at least one axial end face, wherein the free ends of a plurality of hairpin conductor bar pairs are received in openings of an insulating ring according to claim 1, wherein at least these openings are filled by a preferably electrically insulating potting compound and the insulating ring rests on the axial end face of the stator via the at least one spacer element extending axially out of the base body of the insulating ring, without torques being able to be transmitted between the insulating ring and the stator.

[0030] This ensures that no vibrations during stator operation are transmitted to the insulation ring in the circumferential direction, making the insulation of the hairpin winding head significantly more durable and resistant to unwanted cracking. Even if cracks do form in the potting compound, the insulation ring helps prevent or reduce the propagation of such cracks and further damage caused by electrical leakage.

[0031] Furthermore, the invention can also be further developed in such a way that the at least one spacer element does not have a casting compound on its section contacting the stator, which can also contribute to a lightweight construction of the stator.

[0032] In a likewise preferred embodiment variant of the invention, it can also be provided that the at least one holding element of the insulation ring protrudes from the potting compound in the axial direction or is at least not covered by potting compound in the circumferential direction.

[0033] It may also be advantageous to further develop the invention in such a way that the insulation ring is fixed in the circumferential direction, in the radial direction and in an axial direction relative to the hairpin winding only via the potting compound, which also prevents or at least reduces the risk of unwanted crack formation and the formation of electrical creepage distances.

[0034] The object of the invention is finally also achieved by a method for producing a stator for an electrical machine within a drive train of a motor vehicle, comprising the following steps: providing a stator, wherein the stator is cylindrical in shape and a winding head of a hairpin winding extends axially out of the stator on at least one axial end face,

[0035] - Providing an insulation ring, in particular an insulation ring according to one of claims 1-4, wherein the insulation ring has an annular disk-shaped base body with a plurality of openings extending axially through the base body, as well as a spacer element extending out of the base body at least in a first axial direction and at least one holding element extending out of the base body in a second axial direction,

[0036] - placing the insulation ring on the winding head of the hairpin winding, so that the openings are each penetrated at least partially by the free ends of a hairpin conductor bar pair, and the insulation ring rests against the axial end face of the stator via the at least one spacer element extending axially from the base body of the insulation ring, without torque being transferable between the insulation ring and the stator,

[0037] - Fixing a casting tool relative to the at least one holding element of the insulation ring in the axial and circumferential direction,

[0038] - Filling the openings with a casting compound using the casting tool,

[0039] - Removing the potting tool from the at least one holding element.

[0040] Finally, the method according to the invention can also be advantageously implemented such that the casting tool is fixed relative to the at least one holding element of the insulation ring in the axial and circumferential directions before the insulation ring is placed on the winding head of the hairpin winding, so that the insulation ring is placed on the winding head by the casting tool. The invention will be explained in more detail below with reference to figures without limiting the general inventive concept.

[0041] It shows:

[0042] Figure 1 shows an insulation ring in a perspective view,

[0043] Figure 2 shows a stator with an insulation ring placed on the winding head of a hairpin winding in a perspective view,

[0044] Figure 3 shows a detailed view of the insulation ring placed on the winding head of the hairpin winding in a perspective view,

[0045] Figure 4 shows a stator with a cast insulation ring placed on the winding head of a hairpin winding in a perspective view,

[0046] Figure 5 shows a hybrid and a fully electric motor vehicle in a schematic block diagram.

[0047] Figure 1 shows an insulation ring 1 for a winding head 2 of a hairpin winding 3 of a stator 4 of an electrical machine 5, such as is used, for example, within a drive train 15 of a motor vehicle 16, which is sketched as an example in Figure 5.

[0048] The insulation ring 1 has an annular disk-shaped base body 6 with a plurality of openings 7 extending axially through the base body 6, each of which can be penetrated at least partially by the free ends 8 of a hairpin conductor bar pair 9, which can be clearly seen when viewed together with Figure 3.

[0049] Three spacer elements 10 extend in a first axial direction, and three retaining elements 12 extend in a second axial direction from the base body 6. The spacer elements 10 and the retaining elements 12 are arranged equidistantly along the circumference of the insulating ring 1. In the embodiment shown, the spacer elements 10 and the retaining elements 12 each form mutually associated pairs 13, each of which is positioned in a common circumferential segment 14 of the insulating ring 1. The insulating ring 1 is formed in one piece from a plastic material by means of an injection molding process.

[0050] The openings 7 of the insulation ring 1 are arranged along concentrically extending diameters in the annular disk-shaped base body 6. On a diameter, the openings 7 are positioned equidistant from one another. Figure 1 also clearly shows that the openings 7 are positioned on the concentrically extending diameters in circumferentially distributed groups of radially aligned openings 7, with the radially aligned openings 7 of a group also being equidistant from one another.

[0051] In the illustrated embodiment, the openings 7 are essentially identically rectangular in shape with rounded corners, with their longitudinal extension oriented in the circumferential direction of the insulating ring 1. The design of the openings 7 is selected such that the hairpin conductor bar pairs 9 accommodated in an opening 7 ideally do not contact the opening 7, so that potting compound 18 can ensure complete insulation between the hairpin conductor bar pairs 9 and the openings 7. In other words, the insulating ring 1 has no contact with the winding head 2.

[0052] The spacer elements 10 and the holding elements 12 are formed monolithically with the base body 6.

[0053] The three spacer elements 10 are designed as webs arranged on the radially outer diameter of the annular disc-like base body. These spacer elements 10 extend in the axial direction in a trapezoidal shape, with the long trapezoidal side facing the base body 6 and the short trapezoidal side facing the stator 4. The three spacer elements 10 are formed from identical parts. The three retaining elements 12 are also designed as webs, but have a cylindrical configuration and are arranged on the radially outer diameter of the annular disc-like base body 6. The three retaining elements 12 are formed from identical parts.

[0054] The underside of the base body 6 can have a slight slope so that when the casting compound 18 is filled in from below, no gas bubbles remain on or in the base body 6.

[0055] Figure 2 shows a stator 4 for an electric machine 5, such as is used, for example, within a drive train 15 of a motor vehicle 16. The stator 4 is cylindrical in shape, and a winding head 2 of a hairpin winding 3 extends axially out of the stator 4 on at least one axial end face 17. The hairpin winding 3 can be connected via the HV terminal 20 to power electronics for supplying current to the hairpin winding 3. This connection is made via HV connection pins 21 of the hairpin winding 3 that protrude axially from the winding head 2, as also shown in Figure 3.

[0056] The free ends 8 of a plurality of hairpin conductor bar pairs 9 are received in the openings 7 of the insulating ring 1, as known from Figure 1. Figure 2 thus shows the stator 4 with the insulating ring 1 placed on the winding head 2. These openings 7 of the insulating ring 1 are filled with a preferably electrically insulating potting compound 18, as shown in Figure 4.

[0057] The insulation ring 1 rests against the axial end face 17 of the stator 4 via the three spacer elements 10 extending axially from the base body 6 of the insulation ring 1, without any torque being transferable between the insulation ring 1 and the stator 4. Thus, there is no circumferential positioning, no locking, or other positional securing between the insulation ring 1 and the stator 4 in the circumferential direction. The insulation ring 1 is thus fixed relative to the hairpin winding 3 in the circumferential direction, in the radial direction, and in an axial direction only via the potting compound 13. Figure 2 also shows that the twist side and the HV termination terminal 20 side of the hairpin winding 3 are located in the same winding head 2. In the area of ​​the HV connection terminal, the hairpins are twisted differently than in the rest of the winding head 2, which prevents additional possible creepage distances between terminal pins and welded hairpins.

[0058] As shown in Figure 3, some of the openings 7 can also be completely or partially covered by a cover element 11. The cover element 11 is formed integrally with the insulation ring 1 or as a separate component that is fixed to the insulation ring 1. A cover element 11 can lengthen the creepage distances between the conductors of the winding head 2, thereby increasing safety against unwanted local short circuits in the winding head 2.

[0059] A possible method for producing a stator 4, as known from Figures 2 and 4, is explained in more detail below.

[0060] First, a stator 4 is provided, wherein the stator 4 is cylindrical in shape and a winding head 2 of a hairpin winding 3 extends axially out of the stator 4 on at least one axial end face 17.

[0061] Furthermore, an insulation ring 1 is provided, as is known from Figure 1, wherein the insulation ring 1 has an annular disk-shaped base body 6 with a plurality of openings 7 extending axially through the base body 6, as well as a spacer element 10 extending out of the base body 6 at least in a first axial direction and at least one holding element 12 extending out of the base body 6 in a second axial direction.

[0062] The insulation ring 1 is then secured in both the axial and circumferential directions relative to a potting tool by means of the three holding elements 12 of the insulation ring 1. The insulation ring 1, which is secured relative to the potting tool, is then placed onto the winding head 2 of the hairpin winding 3 by the potting tool, such that the openings 7 are each at least partially penetrated by the free ends 8 of a hairpin conductor bar pair 9, and the insulation ring 1 rests against the axial end face 17 of the stator 4 via the at least one spacer element 10 extending axially from the base body 6 of the insulation ring 1, without any torque being transmitted between the insulation ring 1 and the stator 4. This assembled state of the stator 4 is shown in Figure 2, but without the potting tool.

[0063] In the mounted state of the insulation ring 1, the openings 7 are then filled with a potting compound 18 using the potting tool. Finally, the potting tool is removed from the holding elements 12, resulting in the manufacturing state of the stator 4 shown in Figure 4.

[0064] It can be seen that the three retaining elements 12 of the insulation ring 1 protrude axially from the potting compound 18. It would then be possible to separate the protruding retaining elements 12, creating a flat, ring-disk-like end face of the potting compound 18.

[0065] The invention is not limited to the embodiments illustrated in the figures. The above description is therefore not to be considered restrictive, but rather explanatory. The following claims are to be understood as meaning that a stated feature is present in at least one embodiment of the invention. This does not exclude the presence of further features. Where the claims and the above description define 'first' and 'second' features, this designation serves to distinguish between two similar features without establishing a priority. List of reference symbols

[0066] 1 insulation ring

[0067] 2 winding head

[0068] 3 Hairpin winding

[0069] 4 Stator

[0070] 5 electric machine

[0071] 6 basic bodies

[0072] 7 openings

[0073] 8 hairpin ends

[0074] 9 Hairpin conductor rod pair

[0075] 10 spacer element

[0076] 11 Cover element

[0077] 12 Holding element

[0078] 13 pairs

[0079] 14 Circumferential segment

[0080] 15 Powertrain

[0081] 16 motor vehicle

[0082] 17 Front side

[0083] 18 Potting compound

[0084] Section 19

[0085] 20 HV connection terminal

[0086] 21 HV connection pin

Claims

Claims: Insulation ring (1) for a winding head (2) of a hairpin winding (3) of a stator (4) of an electric machine (5) within a drive train (15) of a motor vehicle (16), wherein the insulation ring (1) has an annular base body (6) with a plurality of openings (7) extending axially through the base body (6), each of which can be penetrated at least partially by the free ends (8) of a hairpin conductor pair (9), characterized in that at least one spacer element (10) extends out of the base body (6) in a first axial direction and at least one retaining element (12) extends out of the base body (6) in a second axial direction. Insulation ring (1) according to claim 1, characterized in that the insulation ring (1) has at least three spacer elements (10) and / or at least three retaining elements (12).Insulation ring (1) according to one of the preceding claims, characterized in that the spacer elements (10) and / or the retaining elements (12) are arranged equidistantly along the circumference of the insulation ring (1). Insulation ring (1) according to one of the preceding claims, characterized in that the spacer elements (10) and the retaining elements (12) each form pairs (13) assigned to one another, each pair being positioned in a common circumferential segment (14) of the insulation ring (1). Stator (4) for an electric machine (5) within a drive train (15) of a motor vehicle (16), wherein the stator (4) is cylindrically ring-shaped and a winding head (2) of a hairpin winding (3) extends axially out of the stator (4) at at least one axial end face (17), characterized in that the free ends (8) of a plurality of hairpin conductor pairs (9) are received in openings (7) of an insulating ring (1) according to claim 1, wherein at least these openings (7) are filled with a preferably electrically insulating potting compound (18) and the insulating ring (1) bears against the axial end face (17) of the stator (4) via the at least one spacer element (10) extending axially out of the base body (6) of the insulating ring (1), without torques being transmissible between the insulating ring (1) and the stator (4).Stator (4) according to claim 5, characterized in that the at least one spacer element (10) has no potting compound (18) on its section (19) that contacts the stator (4). Stator (4) according to claim 5 or 6, characterized in that the at least one retaining element (12) of the insulation ring (1) projects axially out of the potting compound (18) or is at least not covered by potting compound (18) in a circumferential direction. Stator (4) according to any one of claims 5-7, characterized in that the insulation ring (1) is fixed relative to the hairpin winding (3) only by means of the potting compound (18) in the circumferential direction, in the radial direction, and in an axial direction. Method for manufacturing a stator (4) for an electric machine (5) within a powertrain (15) of a motor vehicle (16), comprising the following steps: - Provision of a stator (4), wherein the stator (4) is cylindrical ring-shaped and a winding head (2) of a hairpin winding (3) extends axially out of the stator (4) at at least one axial end face (17), - Provision of an insulating ring (1), in particular an insulating ring (1) according to one of claims 1-4, wherein the insulating ring (1) has an annular base body (6) with a plurality of openings (7) extending axially through the base body (6), as well as a spacer element (10) extending out of the base body (6) at least in a first axial direction and at least a retaining element (12) extending out of the base body (6) in a second axial direction, - Placing the insulation ring (1 ) onto the winding head (2) of the hairpin winding (3) such that the openings (7) are at least partially penetrated by the free ends (8) of a hairpin conductor pair (9), and the insulation ring (1) rests against the axial end face (17) of the stator (4) via the at least one spacer element (10) extending axially out of the base body (6) of the insulation ring (1 ), without any torques being transmissible between the insulation ring (1 ) and the stator (4), - Fixing a potting tool relative to the at least one retaining element (12) of the insulating ring (1) in axial and circumferential directions, - Filling the openings (7) with a potting compound (18) using the potting tool, - Removal of the potting tool from the at least one retaining element (12). Method according to claim 9, characterized in that the potting tool is fixed to the at least one retaining element (12) of the insulation ring (1) in the axial and circumferential direction before the insulation ring (1) is placed on the winding head (2) of the hairpin winding (3), so that the insulation ring (1) is placed on the winding head (2) by the potting tool.

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