Stator, method and manufacturing device for producing a stator

Abstract

The invention relates to a stator (1) for an electric machine (2), comprising a plurality of circumferentially distributed stator slots (3), which extend axially through the stator (1) and in each of which a plurality of electrical conductors (4) of a stator winding (5) are arranged, which electrical conductors exit the stator slots (3) axially on both sides, thereby forming a winding head (26a, 26b) in each case, wherein a slot insulation paper (6) is arranged in each case between a stator slot (3) and the conductors (4) accommodated therein, which slot insulation paper electrically insulates the stator slot (3) with respect to the conductors (4), and wherein the slot insulation papers (6) have a substantially U-shaped cross-sectional contour, having a base (7) which extends in the circumferential direction and from which a first free limb (8) and a second free limb (9) each extend away from the base (7) in the radial direction, and the slot insulation papers (6) protrude axially from the stator slots (3) with a protruding section (11) on at least one end face (10) of the stator, wherein the circumferential distance (12) between the first free limb (8) and the second free limb (9) increases in the protruding section (11) of the slot insulation papers (6) as the axial distance (13) increases when viewed from a stator slot (3).

Description

[0001] Stator, method and manufacturing device for the production of a stator

[0002] The present invention relates to a stator for an electric machine comprising a plurality of circumferentially distributed stator slots extending axially through the stator, in each of which a plurality of electrical conductors of a stator winding are arranged, which emerge axially from the stator slots on both sides, forming a winding head, wherein a slot insulating paper is arranged between each stator slot and the conductors received therein, which electrically insulates the stator lamination stack in the slot area from the conductors, and wherein the slot insulating papers have a substantially egg-shaped cross-sectional contour, with a circumferentially extending base from which a first free leg and a second free leg extend radially away from the base.and the slot insulation papers protrude axially from the stator slots at at least one end face of the stator with a projection section, wherein in the projection section of the slot insulation papers the circumferential distance between the first free leg and the second free leg increases with increasing axial distance when viewed from a stator slot. The invention further relates to a method and a manufacturing device for producing a stator.

[0003] The state of the art regarding stators, processes, and manufacturing equipment for producing stators for electrical machines reveals a multitude of developments aimed at optimizing the electrical and mechanical properties of stators. In particular, the design of the stator slots, the positioning of the winding conductors, and the execution of the slot insulation play a central role in the efficiency and longevity of the electrical machine.

[0004] In known stator manufacturing processes, slot insulation papers are used to insulate the electrical conductors within the stator slots from each other and from the stator itself. These slot insulation papers are typically inserted into the stator slots manually or semi-automatically, which can lead to inaccuracies and uneven positioning. This poses a particular problem during the subsequent insertion of the electrical winding conductors, as it can damage the slot insulation paper, compromising its electrical insulation. Furthermore, inaccurate positioning of the slot insulation papers can result in inefficient heat dissipation, negatively impacting the service life of the stator and the electrical machine as a whole.

[0005] Furthermore, conventional slot insulation papers often have a fixed shape that is not optimally adapted to the specific requirements of the winding head. This results in the winding conductors not being guided with the desired curvature as they exit the stator slots. Consequently, the bending radius of the winding conductors remains relatively large, which increases the installation space of the winding head and compromises the compactness of the electrical machine. Another problem is that such designs often require thermal post-treatment of the slot insulation paper to ensure dimensional stability. This post-treatment carries the risk of material failure, particularly cracking or deformation of the slot insulation paper, which negatively affects the electrical insulation capacity and the mechanical strength of the stator.

[0006] Known manufacturing devices for forming the slot insulation papers and inserting them into the stator slots often lack the necessary precision and repeatability to ensure consistently high product quality. In particular, during the forming process, there is a risk that the paper will slip or deform, leading to incorrect alignment of the paper's legs in the stator slot. This can not only impair electrical insulation but also cause mechanical stresses that can ultimately lead to material failure.

[0007] It is therefore an object of the invention to provide an improved stator and an improved method for manufacturing a stator, which avoids or at least reduces the problems known from the prior art. It is also an object of the invention to realize an optimized manufacturing device for producing a stator.

[0008] This problem is solved by a stator for an electric machine comprising a plurality of circumferentially distributed stator slots extending axially through the stator, in each of which a plurality of electrical conductors of a stator winding are arranged, which emerge axially from the stator slots on both sides, forming a winding head, wherein a slot insulating paper is arranged between each stator slot and the conductors received in it, which electrically insulates the stator slot from the conductors, and wherein the slot insulating papers have a substantially U-shaped cross-sectional contour, with a circumferentially extending base from which a first free leg and a second free leg extend radially away from the base, and the slot insulating papers project axially from the stator slots at at least one end face of the stator with a protruding section.wherein in the overhang section of the slot insulation papers the circumferential distance between the first free leg and the second free leg increases with increasing axial distance when viewed from a stator slot, wherein the circumferential distance increases such that an imaginary connecting line of the first free leg from its axial end to the beginning of the overhang section forms an angle of 30-50° to an axial extension axis of the stator slot, and an imaginary connecting line of the second free leg from its axial end to the beginning of the overhang section forms an angle of 30-50° to an axial extension axis of the stator slot.

[0009] This stator offers the advantage that the defined angular increase of the slots in the slot insulation paper in the overhang section enables optimized guidance and insulation of the winding conductors. In particular, the widened cross-section of the slot insulation element outside the slot allows for better adaptation to the curvature of the winding conductors. This results in a reduced radius of curvature and a more compact winding head, which reduces the installation space required for the electric machine and increases its efficiency. Furthermore, the mechanical stress on the slot insulation paper in this critical area is minimized, thus preventing material failure and extending the stator's service life.

[0010] The described topology applies equally to radial and axial flux machines that have slot insulation papers with an essentially U-shaped cross-sectional contour.

[0011] The object of the invention is therefore also achieved by a stator for an electric machine, in particular an axial flux machine, comprising a plurality of circumferentially distributed stator slots extending radially through the stator in which a plurality of electrical conductors of a stator winding are arranged, which extend radially out of the stator slots on both sides, forming a winding head in each case, wherein a slot insulating paper is arranged between each stator slot and the conductors received in it, which electrically insulates the stator slot from the conductors, and wherein the slot insulating papers have a substantially U-shaped cross-sectional contour, with a base extending in the radial direction from which a first free leg and a second free leg extend tangentially away from the base in each case.and the slot insulation papers protrude radially from the stator slots on at least one circumferential surface of the stator with a projection section, wherein in the projection section of the slot insulation papers the circumferential distance between the first free leg and the second free leg increases with increasing radial distance viewed from a stator slot, wherein the circumferential distance increases in such a way thatthat an imaginary connecting line of the first free leg from its radial end to the beginning of the overhang section forms an angle of 30-50° to a radial axis of the stator slot, and an imaginary connecting line of the second free leg from its radial end to the beginning of the overhang section forms an angle of 30-50° to a radial axis of the stator slot. For the purposes of this patent application, the preferred range of the angle-to-elongation-at-break ratio of the slot insulation paper for aramid fiber-based insulation materials such as Nomex is between 1.27% and 2.07%. For foil-based or film-based insulation materials, this range can vary based on different elongation at break. For polyamide film-based Kapton, this ratio is between 1.5% and 3.07%, and for polyester film-based Mylar, between 0.37% and 1.07%.0.7%. Within this range, an optimal balance is achieved between the mechanical strength and the elongation of the slot insulation paper. A ratio within this range ensures that the angle of the legs of the slot insulation paper for radial flux machines, relative to the axial extension axis of the stator slot, is designed such that the material exhibits the necessary flexibility under appropriate tensile stress without premature breakage. At the same time, sufficient stability of the slot insulation paper is ensured.to ensure reliable electrical insulation of the winding conductors. The angle is determined based on the geometric orientation of the slot insulation paper in the stator slot. An imaginary line is drawn from the axial end of the first free leg of the slot insulation paper to the beginning of the overhanging section. This line forms an angle with the axial axis of the stator slot. To determine this angle, the geometric arrangement of the slot insulation paper in the stator slot is measured. The elongation at break is determined by mechanical tensile tests, in which the slot insulation paper is subjected to axial stress to determine the material's elongation properties. A section of the slot insulation paper with a defined length, typically 80 mm in this case, is clamped in a tensile testing machine. The material is then pulled apart at a constant speed.until it tears. During this process, the elongation of the material is measured, i.e., the extension of the slot insulation paper as a percentage of its original length. The elongation at break describes the maximum percentage of elongation the material experiences before it fails.

[0012] First, the individual elements of the claimed item are examined.

[0013] The subject matter of the invention is explained in the order in which it is mentioned in the claim set, and particularly preferred embodiments of the subject matter of the invention are described below.

[0014] Electrical conductor

[0015] For the purposes of this patent application, an electrical conductor is a component used to transport electric current from one point to another within a stator. The electrical conductor is preferably made of a highly conductive material, such as copper or aluminum, to enable efficient current transmission. The conductor cross-sections and their specific shape can vary, with round or rectangular cross-sections being preferred to optimize installation in the stator slots and achieve maximum packing density.

[0016] The function of the electrical conductor is therefore primarily to conduct the electric current within the stator winding, thereby generating the electromagnetic interaction necessary for the operation of the electric machine. The electrical conductors contribute significantly to the formation of the magnetic field in the stator, which, in interaction with the rotor, generates the desired torque. Advantageously, in a radial flux machine, the conductors extend axially through the stator slots, and in an axial flux machine, they extend radially through the slots, emerging from both sides as winding heads to enable the electrical connection between the different winding sections.

[0017] The electrical conductor structure preferably includes an insulating sheath to prevent short circuits between adjacent conductors and an electrical connection with the stator slots. Within the stator slots, the electrical conductors are surrounded by a slot insulation paper, which additionally contributes to electrical insulation and ensures the mechanical stability of the winding.

[0018] Stator winding

[0019] For the purposes of this patent application, a stator winding is an arrangement of electrical conductors embedded in the stator slots of an electric machine and serving to generate a magnetic field when an electric current flows through it. The stator winding, by generating and maintaining a rotating magnetic field, causes the torque and movement of the rotor.

[0020] The stator winding preferably consists of a plurality of conductors, which, in the case of a radial flux machine, are distributed in the axial slots of the stator, and in the radial slots of an axial flux machine. Each of these conductors is electrically insulated to prevent short circuits and other electrical disturbances. In a radial flux machine, the conductors run axially through the stator, and in an axial flux machine, they run radially through the stator, emerging from the slots at both ends to form winding heads. These winding heads serve to electrically connect the conductors and enable the closed circuit of the winding.

[0021] Advantageously, the stator winding is designed so that the conductors are arranged in a precise pattern to maximize the efficiency of the electric machine. This includes both minimizing electrical losses and optimizing the generated magnetic field, resulting in higher power density and improved machine efficiency.

[0022] The stator winding can be designed in particular as a hairpin winding or wave winding.

[0023] For the purposes of this patent application, a slot insulation paper is an insulating component positioned in the stator slots of an electric machine to electrically insulate the electrical conductors of the stator winding from the metallic stator core. The slot insulation paper fulfills the essential function of preventing electrical breakdowns between the winding conductors and the stator, thereby ensuring safe and stable operation of the electric machine. In the context of this description, slot insulation papers are synonymous with other sheet insulating materials such as films or fabrics. The slot insulation paper is designed to have a substantially i-shaped cross-sectional contour that optimally adapts to the geometry of the stator slot.It consists of a base extending circumferentially in both radial and axial flux machines, from which two legs extend radially outwards in the case of radial flux machines and tangentially outwards in the case of axial flux machines, so that the electrical conductors in the slot are completely surrounded by the insulating material. The overhanging section of the slot insulation paper, which projects axially or radially beyond the stator, provides additional insulation in the area of ​​the winding heads, where the conductors exit the stator slots and are bent.

[0024] The slot insulation paper preferably consists of a high-strength and heat-resistant material that withstands both the mechanical and thermal stresses encountered during the operation of the electrical machine over extended periods. Preferred materials include special types of paper coated with an insulating layer of plastics such as polyimide, polyester, or Nomex. These materials offer excellent electrical insulation properties while also being resistant to mechanical stresses that occur during assembly and operation.

[0025] Possible embodiments of the slot insulation paper include those composed of multiple layers, each fulfilling specific requirements. For example, the outer layer can be particularly abrasion-resistant and resistant to mechanical damage, while the inner layer ensures particularly good dielectric insulation. Reinforced or fiber-reinforced materials can also be used to increase stability and further extend the service life of the insulation material. Another possible embodiment could involve providing the slot insulation paper with an additional thermally stable binder, ensuring improved strength in the winding head area without compromising the paper's flexibility and conformability.

[0026] For the purposes of this patent application, a projection section is the portion of the slot insulation paper that protrudes axially from the stator slots in a radial flux machine and radially from the stator slots in an axial flux machine. The projection section thus extends beyond the end face of the stator in a radial flux machine and beyond the circumferential surfaces of the stator in an axial flux machine, forming a region that extends beyond direct contact with the conductors within the slot. This section of the slot insulation paper has a U-shaped cross-sectional contour, with the free legs of the U-profile extending axially and radially outwards from the stator slot, respectively. The two legs of the projection section increase in distance from the stator slot with increasing distance, thereby creating a widening effect.

[0027] The primary function of the overhang section is to ensure secure and stable insulation of the winding conductors beyond the slot, extending into the area of ​​the winding head. By widening its cross-section, the overhang section allows for controlled bending of the winding conductors as they exit the slot, without damaging the slot insulation paper or compromising its shape. This contributes to improved mechanical stability and optimized conductor routing, resulting in a more compact winding head design. Furthermore, the overhang section increases insulation efficiency by comprehensively covering the conductor exit area, thus reducing the risk of short circuits and electrical faults.

[0028] connecting line

[0029] For the purposes of this patent application, an imaginary connecting line is a line that runs between two defined points of a component or structure and is used to describe geometric relationships or relative positions. In the present invention, the imaginary connecting line specifically refers to the line that, in a radial flux machine, runs from the axial end of a free leg of the slot insulation paper to a defined reference point, such as the beginning of the overhang section. This line serves to define an angle that describes the course of the legs relative to the axial axis of the stator slot. The imaginary connecting line enables a precise description of the geometric design of the slot insulation papers, particularly in the overhang section, and contributes to the accurate definition of the leg contour.By defining an angle between the connecting line and the axial extension axis, the course of the legs with respect to the slot and its axial direction is characterized. This is particularly important for the manufacture and function of the slot insulation papers, as this angle results in a preferred expansion of the legs, which enables optimized guidance of the winding conductors outside the stator slots.

[0030] The function of the imaginary connecting line is to define the geometry of the legs in such a way as to ensure ideal curvature and positioning of the winding conductors. This widening of the legs allows the winding conductors to emerge from the groove with an advantageous radius of curvature, without damaging the material of the groove insulation papers or compromising their dimensional stability.

[0031] For the purposes of this patent application, an active length is that section of the stator in which the electrical conductors of the stator winding are positioned such that they actively participate in generating the electromagnetic field and thereby effect the conversion of electrical energy into mechanical energy or vice versa. In a radial flux machine, the active length extends axially along the stator, and in an axial flux machine, it extends radially. It lies within the region of the magnetic flux generated by the rotor of the electric machine. In this zone, the magnetic fields of the rotor and the winding currents in the stator interact to generate the desired rotational motion or electrical power.

[0032] For the purposes of this patent application, a conductor length is the length of an electrical conductor that extends in a straight line in the axial direction of the stator in the case of a radial flux machine and in the radial direction of an axial flux machine, whereby the conductor length may also include sections protruding axially or radially from the slots before the conductor is deformed in the winding head. These sections of the conductor protruding axially from the slots are part of the conductor length as long as they are not yet deformed and contribute to the electrical connection within the stator winding. The conductor length is therefore generally greater than the active length.

[0033] For the purposes of this patent application, a forming tool is a device used to shape slot insulation paper into a predetermined form. The forming tool serves to shape the slot insulation paper so that it can be inserted precisely into the stator slots of a stator for an electric machine. It comprises, in particular, a die into which the slot insulation paper is placed, and a punch that presses the paper into the die, thereby achieving the desired shape.

[0034] Preferably, the forming tool is designed to enable the precise forming of the slot insulation paper into an essentially U-shaped cross-sectional contour. In a radial flux machine, this contour consists of a base extending circumferentially, and in an axial flux machine, radially, of the stator, along with two free legs extending radially or axially from the base, respectively. The die of the forming tool exerts uniform pressure on the slot insulation paper, ensuring that it precisely assumes the shape of the negative form of the die. Advantageously, the die is equipped with a negative form that reflects the exact geometry of the subsequent stator slot, thus ensuring a high degree of dimensional accuracy for the slot insulation paper.

[0035] die

[0036] For the purposes of this patent application, a die is a shaping component of a tool used to form a slot insulation paper into a desired cross-sectional contour. The die has a negative form that corresponds to the final geometry of the slot insulation paper and, during the embossing process, brings the paper into its defined shape. The die forms a precisely defined shape into which the slot insulation paper is pressed by the pressure of a die. Preferably, the die is made of a dimensionally stable material that is sufficiently resistant to withstand the mechanical stresses generated during embossing over many production cycles without losing its geometric accuracy.

[0037] For the purposes of this patent application, a punch is a component of the forming tool that serves to bring the slot insulation paper into a predetermined shape by pressing the material into a corresponding die. The punch exerts mechanical pressure on the slot insulation paper, ensuring that it is formed into the desired U-shaped cross-section. The punch preferably comprises a pressure-transmitting surface whose geometry is precisely adapted to the negative shape of the die. This pressure-transmitting surface is smooth and has a high surface quality to ensure that the slot insulation paper is formed uniformly and gently during the embossing process. Preferably, the punch is made of a high-strength material that withstands repeated mechanical stress without deformation or wear. Furthermore, it is stably mounted to ensure precise alignment during the pressing process.

[0038] hold-down device

[0039] For the purposes of this patent application, a hold-down device is a component or device used during the embossing process to press the slot insulation paper, or its legs, against a die to ensure its precise positioning and shaping. The hold-down device exerts controlled pressure on the slot insulation paper, preventing it from slipping during processing. This ensures a uniform and accurate forming of the slot insulation paper into the desired shape, which is crucial for its subsequent functionality and dimensional accuracy.

[0040] Preferably, the blank holder is made of a robust material capable of absorbing the forces occurring during embossing without deforming itself or damaging the groove insulation paper. Advantageously, it is positioned in the manufacturing device such that it moves synchronously with the die during the embossing process and securely presses the groove insulation paper against the die. The blank holder's design advantageously includes a flat contact surface large enough to fix the groove insulation paper at the relevant points without creating unwanted creases or pressure marks.

[0041] Advantageous embodiments of the invention

[0042] According to an advantageous embodiment of the invention, it can be provided that the electrical conductors have a conductor length extending in a straight axial direction, which is greater than or equal to the active length of the stator but less than the axial extent of the slot insulation papers, or that the electrical conductors have a conductor length extending in a straight radial direction, which is greater than or equal to the active length of the stator but less than the radial extent of the slot insulation papers.

[0043] By dimensioning the electrical conductors in relation to the active length of the stator, the advantage arises that the winding conductors can be optimally matched to the physical requirements of the machine. This leads to improved current-carrying capacity and lower electrical losses, as the conductors are neither unnecessarily long nor too short. Furthermore, the shorter length of the slot insulation paper compared to the conductors ensures more precise insulation, which contributes to reducing electrical interference and increasing operational reliability.

[0044] According to a further preferred embodiment of the invention, the slot insulation papers in the area of ​​the winding head can also have a continuous angle and no straight sections. This significantly reduces the risk of material damage, such as cracks or deformations. This allows for a longer service life of the winding and increased reliability of the electric machine. Furthermore, this shape contributes to a better adaptation to the geometry of the winding head, resulting in more efficient and precise insulation. The object of the invention is further achieved by a method for manufacturing a stator for an electric machine comprising the following steps:

[0045] • Provision of an unwound stator with a plurality of circumferentially distributed stator slots extending axially through the stator in which a plurality of electrical conductors of a stator winding can be arranged, which then exit the stator slots axially on both sides, forming a winding head in each case;

[0046] • Provision of a plurality of electrical conductors to form a stator winding;

[0047] • Provision of a plurality of slot insulation papers, each of which can be positioned between a stator slot and the conductors received in it, so that the respective stator slot can be electrically insulated from the conductors;

[0048] • Provision of a forming tool for shaping the slot insulation papers into a shape predefined by the forming tool;

[0049] • Inserting a slot insulation paper into the forming tool and forming the slot insulation paper in such a way that

[0050] • the slot insulation papers, after forming, have an essentially U-shaped cross-sectional contour, with a circumferentially extending base from which a first free leg and a second free leg extend radially away from the base, and

[0051] • the slot insulation papers can protrude axially from the stator slots at at least one end face of the stator with an overhang section, wherein in the overhang section of the slot insulation papers the circumferential distance between the first free leg and the second free leg increases with increasing axial distance when viewed from a stator slot, and

[0052] • The circumferential distance increases so that an imaginary connecting line of the first free leg from its axial end to the beginning of the overhang section has an angle of 30-50° to an axial extension axis of the stator slot and

[0053] • an imaginary connecting line of the second free leg from its axial end to the beginning of the overhang section has an angle of 30-50° to an axial extension axis of the stator slot.

[0054] • Inserting the reshaped slot insulation paper into a stator slot of the stator;

[0055] • Inserting the electrical conductors into the stator slot lined with the slot insulation paper.

[0056] The problem of the invention can also be solved by a method for manufacturing a stator for an electrical machine, in particular an axial flux machine, comprising the following steps:

[0057] • Provision of an unwound stator with a plurality of circumferentially distributed stator slots extending radially through the stator in which a plurality of electrical conductors of a stator winding can be arranged, which then exit the stator slots radially on both sides, forming a winding head in each case;

[0058] • Provision of a plurality of electrical conductors to form a stator winding;

[0059] Provision of a plurality of slot insulation papers, each of which can be positioned between a stator slot and the conductors received in it, so that the respective stator slot can be electrically insulated from the conductors;

[0060] • Provision of a forming tool for shaping the

[0061] Nut insulation papers into a shape predefined by the forming tool;

[0062] • Inserting a slot insulation paper into the forming tool and forming the slot insulation paper in such a way that

[0063] • the slot insulation papers, after forming, have an essentially U-shaped cross-sectional contour, with a radially extending base from which a first free leg and a second free leg extend tangentially away from the base, and

[0064] • the slot insulation papers can protrude radially from the stator slots with an overhang section on at least one circumferential surface of the stator, wherein

[0065] • in the overhang section of the slot insulation papers, the circumferential distance between the first free leg and the second free leg increases with increasing radial distance when viewed from a stator slot, and

[0066] • The circumferential distance increases so that an imaginary connecting line of the first free leg from its radial end to the beginning of the overhang section has an angle of 30-50° to a radial extension axis of the stator slot and

[0067] • An imaginary connecting line of the second free leg from its radial end to the beginning of the overhang section forms an angle of 30-50° to a radial axis of the stator slot. Insert the formed slot insulation paper into a stator slot of the stator;

[0068] • Inserting the electrical conductors into the stator slot lined with the slot insulation paper.

[0069] The described stator manufacturing process offers the advantage of standardized and reproducible production of high-precision stators. In particular, the targeted reshaping of the slot insulation papers ensures an optimized fit, which improves insulation quality and minimizes the risk of electrical breakdowns. Furthermore, the process allows for greater flexibility in the design of the winding heads, as the winding conductors can be precisely bent and positioned at an early stage of production. This increases the overall manufacturing efficiency and reduces production costs.

[0070] According to a further particularly preferred embodiment of the invention, the formed slot insulation paper can be inserted radially into a stator slot. Inserting the formed slot insulation paper radially into the stator slots offers the advantage of simpler and more precise assembly. This increases the insertion accuracy, which is particularly advantageous in automated manufacturing processes. Furthermore, this approach reduces the risk of damage to the slot insulation papers and the winding conductors during insertion, leading to greater process reliability and improved product quality. In an axial flux machine, insertion can preferably be carried out radially into a stator slot.

[0071] Furthermore, the invention can be further developed such that the forming of the slot insulation paper by the forming tool is carried out by embossing, whereby the slot insulation paper is placed in a die of the forming tool and pressed into the die with a punch. Forming the slot insulation papers by embossing increases the accuracy and consistency of the cross-sectional geometry. This offers the advantage that the slot insulation papers assume a precise shape that can be inserted accurately into the stator slots, thus maximizing electrical insulation performance. In addition, material consumption is optimized, as no additional thermal or mechanical post-treatments are required. This reduces manufacturing costs and increases production efficiency.

[0072] In a further preferred embodiment of the invention, the slot insulation paper may also protrude from the die during embossing by means of two axially extending wings, and these wings are pressed against the die by means of at least one clamp. The use of clamps during the embossing process precisely fixes the slot insulation paper in the die. This offers the advantage that the paper does not slip during forming, ensuring high dimensional accuracy and repeatability. This precise positioning leads to improved dimensional stability of the slot insulation papers and thus to higher product quality and reliability of the electrical insulation during machine operation.

[0073] It can also be advantageous to further develop the invention such that, when the electrical conductors are inserted into the stator groove lined with the slot insulation paper, the wings form a funnel-shaped opening in the radial direction, or, when the electrical conductors are inserted into the stator groove lined with the slot insulation paper, the wings form a funnel-shaped opening in the axial direction. The funnel-shaped opening of the wings of the slot insulation paper when inserting the electrical conductors allows for particularly easy and smooth insertion of the winding conductors. This reduces the mechanical stress on the conductors during assembly, thereby minimizing the risk of damage such as abrasion or crushing. Furthermore, the manufacturing process is accelerated, which increases production efficiency and leads to a reduction in manufacturing costs.

[0074] The object of the invention can also be achieved by a manufacturing device for producing a stator for an electric machine, comprising a forming tool for embossing a slot insulation paper, a die into which a slot insulation paper can be positioned, and a punch by means of which the slot insulation paper can be pressed into the die, wherein the die has a negative shape designed such that, after forming, the slot insulation papers have a substantially U-shaped cross-sectional contour, with a circumferentially extending base from which a first free leg and a second free leg extend radially away from the base, and the slot insulation papers protrude axially from the stator slots at at least one end face of the stator with a projection section.wherein in the overhang section of the slot insulation papers the circumferential distance between the first free leg and the second free leg increases with increasing axial distance when viewed from a stator slot, wherein the circumferential distance increases such that an imaginary connecting line of the first free leg from its axial end to the beginning of the overhang section forms an angle of 30-50° to an axial extension axis of the stator slot, and an imaginary connecting line of the second free leg from its axial end to the beginning of the overhang section forms an angle of 30-50° to an axial extension axis of the stator slot.

[0075] Furthermore, the object of the invention can also be solved by a manufacturing device for producing a stator for an electric machine with a forming tool for embossing a slot insulation paper, comprising a die into which a slot insulation paper can be positioned, and a punch by means of which the slot insulation paper can be pressed into the die, wherein the die has a negative form which is designed such that after forming

[0076] • the slot insulation papers have a substantially U-shaped cross-sectional contour, with a radially extending base from which a first free leg and a second free leg extend tangentially away from the base, and the slot insulation papers project radially from the stator slots on at least one circumferential surface of the stator with a projection section, wherein • in the projection section of the slot insulation papers, the circumferential distance between the first free leg and the second free leg increases with increasing radial distance when viewed from a stator slot, wherein

[0077] • the circumferential distance increases so that an imaginary connecting line of the first free leg from its radial end to the beginning of the overhang section has an angle of 30-50° to a radial extension axis of the stator slot and

[0078] • an imaginary connecting line of the second free leg from its radial end to the beginning of the overhang section has an angle of 30-50° to a radial extension axis of the stator slot.

[0079] The manufacturing device, with its precisely formed negative mold, enables optimal shaping of the slot insulation papers, resulting in improved fit and insulation quality. The use of a specially designed die ensures uniform pressure distribution during the embossing process, increasing the material homogeneity and strength of the slot insulation paper. This results in more durable and robust insulation, improving the overall performance and lifespan of the electrical machine.

[0080] Finally, the invention can also be advantageously implemented such that the manufacturing device has at least one hold-down device by means of which the slot insulation paper is pressed against the die during embossing with two axially extending wings projecting from the die, or the manufacturing device has at least one hold-down device by means of which the slot insulation paper is pressed against the die during embossing with two tangentially extending wings projecting from the die. The use of hold-down devices in the manufacturing device offers the advantage that the slot insulation paper is positioned precisely during the embossing process and secured against unwanted movement. This ensures high repeatability in series production, which increases process reliability and optimizes product quality.Furthermore, the risk of production errors is minimized, leading to greater efficiency in the manufacturing process and a reduction in the scrap rate. The precise positioning of the wings also ensures optimal shaping of the slot insulation papers, contributing to improved insulation performance and a longer service life for the electrical machine.

[0081] The invention will now be explained in more detail with reference to figures, without limiting the general concept of the invention.

[0082] It shows:

[0083] Figure 1 shows an electric machine in a schematic axial sectional view.

[0084] Figure 2 shows an electric machine in a schematic representation

[0085] Cross-sectional view,

[0086] Figure 3 shows a wound stator slot in a schematic cross-sectional view.

[0087] Figure 4 shows a nut insulation paper in a perspective view.

[0088] Figure 5 shows a wound stator slot in a schematic axial section view.

[0089] Figure 6 shows a forming tool comprising a die and a punch, each in a perspective view.

[0090] Figure 7 shows a manufacturing device with a forming tool and a slot insulation paper fixed in the die by means of a hold-down device in a perspective view.

[0091] Figure 8 shows a manufacturing device with a forming tool and a slot insulation paper located in the die after the hold-down has been released, in a perspective view. Figures 1 and 2 show a stator 1 for an electric machine 2 comprising a plurality of circumferentially distributed stator slots 3 extending axially through the stator 1, in each of which a plurality of electrical conductors 4 of a stator winding 5 are arranged, which emerge axially from the stator slots 3 on both sides, forming a winding head 26a, 26b.

[0092] As shown in Figure 3, a slot insulation paper 6 is arranged between each stator slot 3 and the conductors 4 received therein, electrically insulating the stator slot 3 from the conductors 4. The slot insulation papers 6 have a substantially U-shaped cross-sectional contour, with a circumferentially extending base 7 from which a first free leg 8 and a second free leg 9 extend radially away from the base 7. The slot insulation papers 6 project axially from the stator slots 3 at at least one end face 10 of the stator 1 with a projection section 11, as shown in Figure 5. In the projection section 11 of the slot insulation papers 6, the circumferential distance 12 between the first free leg 8 and the second free leg 9 increases with increasing axial distance 13 when viewed from a stator slot 3.In the embodiment of the invention shown, the circumferential distance 12 increases such that an imaginary connecting line 14 of the first free leg 8 from its axial end 15 to the beginning of the overhang section 11 forms an angle 16 of SOSO. 0 to an axial extension axis 17 of the stator groove 3 and an imaginary connecting line 18 of the second free leg 9 from its axial end 19 to the beginning of the overhang section 11 has an angle 20 of 30-50° to an axial extension axis 21 of the stator groove 3.

[0093] Figure 5 further shows that the electrical conductors 4 have a straight, axially extending conductor length 22, which is greater than or equal to the active length 23 of the stator 1 but less than the axial extent 24 of the slot insulation papers 6. The slot insulation papers 6 have a continuous angle in the region of the winding head 26a, 26b and no straight sections. A method for manufacturing the stator 1 can, for example, comprise the following steps. First, an unwound stator 1 is provided with a plurality of circumferentially distributed stator slots 3 extending axially through the stator 1. A plurality of electrical conductors 4 of a stator winding 5 can be arranged in each of these slots, and these conductors then emerge axially from the stator slots 3 on both sides, forming a winding head 26a, 26b.Furthermore, a plurality of electrical conductors 4 are provided for forming a stator winding 5, as well as a plurality of slot insulation papers 6, each of which can be positioned between a stator slot 3 and the conductors 4 received in it, so that the respective stator slot 3 can be electrically insulated from the conductors 4, and a forming tool 30 for forming the slot insulation papers 6 into a shape predefined by the forming tool 30.

[0094] Next, a slot insulation paper 6 is inserted into the forming tool 30 and formed such that, after forming, the slot insulation papers 6 have a substantially U-shaped cross-sectional contour, with a circumferentially extending base 7 from which a first free leg 8 and a second free leg 9 extend radially away from the base 7, and the slot insulation papers 6 can project axially from the stator slots 3 at at least one end face 10 of the stator 1 with a projection section 11, wherein in the projection section 11 of the slot insulation papers 6 the circumferential distance 12 between the first free leg 8 and the second free leg 9 increases with an increasing axial distance 13 when viewed from a stator slot 3, and the circumferential distance 12 increases in such a way thatthat an imaginary connecting line 14 of the first free leg 8 from its axial end 15 to the beginning of the overhang section 11 forms an angle 16 of 30-50° with an axial extension axis 17 of the stator groove 3, and an imaginary connecting line 18 of the second free leg 9 from its axial end 19 to the beginning of the overhang section 11 forms an angle 20 of 30-50° with an axial extension axis 21 of the stator groove 3. The forming of the groove insulation paper 6 by the forming tool 30 is carried out by embossing, in that the groove insulation paper 6 is placed in a die 31 of the forming tool 30 and pressed into the die 31 with a punch 32, which can also be seen with reference to Figure 6.

[0095] The shaped slot insulation paper 6 is then removed from the die 31 and inserted into a stator slot 3 of the stator 1. The electrical conductors 4 are then inserted into the stator slot 3 lined with the slot insulation paper 6. The shaped slot insulation paper 6 is inserted radially into the stator slots 3.

[0096] During embossing, the nut insulation paper 6 protrudes from the die 31 with two axially extending wings 34,35 and the wings 34,35 are pressed against the die 31 by means of two retainers 36a, 36b, as sketched in Figure 7.

[0097] After releasing the retainers 36a, 36b and inserting the electrical conductors 4 into the stator groove 3 lined with the slot insulation paper 6, the wings 34, 35 form a funnel-shaped opening in a radial direction, as can be seen in Figure 8.

[0098] Figures 7-8 thus also show a manufacturing device 40 for producing a stator 1 for an electric machine 2, comprising a forming tool 30 for embossing a slot insulation paper 6, a die 31 in which a slot insulation paper 6 can be positioned, and a punch 32 by means of which the slot insulation paper 6 can be pressed into the die 31, wherein the die 31 has a negative form 33, which is designed such that after forming the slot insulation papers 6 have a substantially U-shaped cross-sectional contour, with a circumferentially extending base 7 from which a first free leg 8 and a second free leg 9 extend radially away from the base 7, and the slot insulation papers 6 protrude axially from the stator slots 3 at at least one end face 10 of the stator 1 with a projection section 11.wherein in the overhang section 11 of the slot insulation papers 6 the circumferential distance 12 between the first free leg 8 and the second free leg 9 increases with increasing axial distance 13 viewed from a stator slot 3, wherein the circumferential distance 12 increases such that an imaginary connecting line 14 of the first free leg 8 from its axial end 15 to the beginning of the overhang section 11 has an angle 16 of 30-50° to an axial extension axis 17 of the stator slot 3 and an imaginary connecting line 18 of the second free leg 9 from its axial end 19 to the beginning of the overhang section 11 has an angle 20 of 30-50° to an axial extension axis 21 of the stator slot 3.

[0099] The manufacturing device 40 has at least one hold-down device 36, by means of which the slot insulation paper 6 is pressed against the die 31 during embossing with two wings 34,35 extending in the axial direction and projecting from the die 31.

[0100] The invention is not limited to the embodiments illustrated in the figures. The preceding description is therefore not to be considered limiting, but rather explanatory. The following claims are to be understood as meaning that a named feature is present in at least one embodiment of the invention. This does not preclude the presence of further features. Where the claims and the preceding description define 'first' and 'second' features, this designation serves to distinguish between two similar features without establishing a hierarchy. Unless otherwise specified, 'radial,' 'axial,' and 'circumferential' refer to the axis of rotation of the respective rotor. List of reference symbols

[0101] 1 Stator

[0102] 2 electric machine

[0103] 3 stator slots

[0104] 4 conductors

[0105] 5 Stator winding

[0106] 6 Nut insulation paper

[0107] 7 Floor

[0108] 8 thighs

[0109] 9 thighs

[0110] 10 Front

[0111] 11 Overhang section

[0112] 12 distance

[0113] 13 Axial distance

[0114] 14 connecting line

[0115] 15 End

[0116] 16 angles

[0117] 17 Axial extension axis

[0118] 18 connecting line

[0119] 19 End

[0120] 20 angles

[0121] 21 Axial extension axis

[0122] 22 ladder length

[0123] 23 Active length

[0124] 24 Axial extension

[0125] 26 winding head

[0126] 30 forming tools

[0127] 31 die

[0128] 32 stamps

[0129] 33 Negative form

[0130] 34 wings

[0131] 35 Wing Hold-Down Manufacturing Device

Claims

Claims 1. Stator (1) for an electrical machine (2), in particular a radial flux machine, comprising a plurality of circumferentially distributed stator slots (3) extending axially through the stator (1), in each of which a plurality of electrical conductors (4) of a stator winding (5) are arranged, which emerge axially from the stator slots (3) on both sides, forming a winding head (26a, 26b), wherein a slot insulating paper (6) is arranged between each stator slot (3) and the conductors (4) received therein, which electrically insulates the stator slot (3) from the conductors (4), and wherein the slot insulating papers (6) have a substantially U-shaped cross-sectional contour, with a circumferentially extending base (7) from which a first free leg (8) and a second free leg (9) extend radially away from the base (7),and the slot insulation papers (6) on at least one end face (10) of the stator (1) with a, The overhanging section (11) projects axially from the stator slots (3), wherein in the overhanging section (11) of the slot insulation papers (6) the circumferential distance (12) between the first free leg (8) and the second free leg (9) increases with increasing axial distance (13) viewed from a stator slot (3), characterized in that the circumferential distance (12) increases such that an imaginary connecting line (14) of the first free leg (8) from its axial end (15) at the beginning of the overhang section (11) has an angle (16) of 30-50° to an axial extension axis (17) of the stator slot (3), wherein the angle (16) is determined based on the geometric orientation of the slot insulation paper (6) in the stator slot (3) and the angle of 30-50° is determined by a ratio of angle (16) to elongation at break of the slot insulation paper (6), and an imaginary connecting line (18) of the second free leg (9) from its axial end (19) to the beginning of the overhang section (11) has an angle (20) of 30-50° to an axial extension axis (21) of the stator groove (3).

2. Stator for an electric machine, in particular an axial flux machine, comprising a plurality of circumferentially distributed stator slots extending radially through the stator, in each of which a plurality of electrical conductors of a stator winding are arranged, which extend radially out of the stator slots on both sides, forming a winding head, wherein a slot insulating paper is arranged between each stator slot and the conductors received therein, which electrically insulates the stator slot from the conductors, and wherein the slot insulating papers have a substantially U-shaped cross-sectional contour, with a base extending in the radial direction from which a first free leg and a second free leg extend tangentially away from the base, and the slot insulating papers project radially out of the stator slots with a projection section on at least one circumferential surface of the stator.wherein in the overhang section of the slot insulation papers the circumferential distance between the first free leg and the second free leg increases with increasing radial distance viewed from a stator slot, characterized in that the circumferential distance increases such that an imaginary connecting line of the first free leg from its radial end to the beginning of the overhang section has an angle of 30-50° to a radial extension axis of the stator slot, wherein the angle (16) is determined on the basis of the geometric orientation of the slot insulation paper (6) in the stator slot (3), is determined and the angle of 30-50° is determined by a ratio of angle (16) to elongation at break of the slot insulation paper (6), and an imaginary connecting line of the second free leg from its radial end to the beginning of the overhang section has an angle of 30-50° to a radial extension axis of the stator slot.

3. Stator (1 ) according to claim 1 or 2, characterized in that the electrical conductors (4) have a conductor length (22) extending in a straight axial direction, which is greater than or equal to the active length (23) of the stator (1 ) but less than the axial extent (24) of the slot insulation papers (6), or the electrical conductors have a conductor length extending in a straight radial direction, which is greater than or equal to the active length of the stator but less than the radial extent of the slot insulation papers.

4. Stator (1 ) according to one of claims 1 to 3, characterized in that the slot insulation papers (6) in the area of ​​the winding head (26a, 26b) have a continuous angle and no straight portions.

5. Method for manufacturing a stator (1 ) for an electrical machine (2), in particular a radial flux machine, comprising the following steps: • Provision of an unwound stator (1 ) with a plurality of circumferentially distributed stator slots (3) extending axially through the stator (1 ) in which a plurality of electrical conductors (4) of a stator winding (5) can be arranged, which are then axially exit the stator slots (3) on both sides, forming a winding head (26a, 26b) on each side; • Provision of a plurality of electrical conductors (4) to form a stator winding (5); • Provision of a plurality of slot insulation papers (6) which can each be positioned between a stator slot (3) and the conductors (4) received in it, so that the respective stator slot (3) can be electrically insulated from the conductors (4); • Provision of a forming tool (30) for forming the slot insulation papers (6) into a shape predefined by the forming tool (30); • Inserting a slot insulation paper (6) into the forming tool (30) and forming the slot insulation paper (6) in such a way that • the nut insulation papers (6) have a substantially U-shaped cross-sectional contour after forming, with a circumferentially extending base (7) from which a first free leg (8) and a second free leg (9) extend radially away from the base (7), and • the slot insulation papers (6) can protrude axially from the stator slots (3) at at least one end face (10) of the stator (1 ) with a projection section (11 ) • in the overhang section (11) of the slot insulation papers (6) the circumferential distance (12) between the first free leg (8) and the second free leg (9) increases with increasing axial distance (13) viewed from a stator slot (3), and • The circumferential distance (12) increases such that an imaginary connecting line (14) of the first free leg (8) from its axial end (15) to the beginning of the overhang section (11) has an angle (16) of 30-50° to an axial extension axis (17) of the stator groove (3) and • an imaginary connecting line (18) of the second free leg (9) from its axial end (19) to the beginning of the overhang section (11) has an angle (20) of 30-50° to an axial extension axis (21) of the stator groove (3). • Inserting the reshaped slot insulation paper (6) into a stator slot (3) of the stator (1 ); • Inserting the electrical conductors (4) into the stator slot (3) lined with the slot insulation paper (6).

6. Method for manufacturing a stator for an electrical machine, in particular an axial flux machine, comprising the following steps: • Provision of an unwound stator with a plurality of circumferentially distributed stator slots extending radially through the stator in which a plurality of electrical conductors of a stator winding can be arranged, which then exit the stator slots radially on both sides, forming a winding head in each case; • Provision of a plurality of electrical conductors to form a stator winding; • Provision of a plurality of slot insulation papers, each of which can be positioned between a stator slot and the conductors received in it, so that the respective stator slot can be electrically insulated from the conductors; Provision of a forming tool for shaping the Nut insulation papers into a shape predefined by the forming tool; • Inserting a slot insulation paper into the forming tool and forming the slot insulation paper in such a way that • the slot insulation papers, after forming, have an essentially U-shaped cross-sectional contour, with a radially extending base from which a first free leg and a second free leg extend tangentially away from the base, and • the slot insulation papers can protrude radially from the stator slots with an overhang section on at least one circumferential surface of the stator, wherein • in the overhang section of the slot insulation papers, the circumferential distance between the first free leg and the second free leg increases with increasing radial distance when viewed from a stator slot, and • The circumferential distance increases so that an imaginary connecting line of the first free leg from its radial end to the beginning of the overhang section has an angle of 30-50° to a radial extension axis of the stator slot and • an imaginary connecting line of the second free leg from its radial end to the beginning of the overhang section has an angle of 30-50° to a radial extension axis of the stator slot. • Inserting the reshaped slot insulation paper into a stator slot of the stator; Inserting the electrical conductors into the stator slot lined with the slot insulation paper.

7. Method according to claim 5 or 6, characterized in that the formed slot insulation paper (6) is inserted into a stator slot (3) from a radial direction.

8. Method according to one of claims 5 to 7, characterized in that the forming of the slot insulation paper (6) by the forming tool (30) is carried out by means of embossing, in that the slot insulation paper (6) is placed into a die (31 ) of the forming tool (30) and pressed into the die (31 ) with a punch (32).

9. Method according to claim 8, characterized in that the nut insulation paper (6) protrudes from the die (31) during embossing with two axially extending wings (34, 35) and the wings (34, 35) are pressed against the die (31) by means of at least one retainer (36).

10. Method according to claim 9, characterized in that when the electrical conductors (4) are inserted into the stator groove (3) lined with the slot insulation paper (6), the wings (34, 35) form a funnel-shaped opening in the radial direction, or when the electrical conductors are inserted into the stator groove lined with the slot insulation paper, the wings form a funnel-shaped opening in the axial direction.

11. Stator or method according to one of the preceding claims, characterized in that the ratio of angle (16,20) to elongation at break of the slot insulation paper (6) is between 0.37%-3.07%.

12. Manufacturing device (40) for producing a stator (1) for an electric machine (2) with a forming tool (30) for embossing a slot insulation paper (6) comprising a die (31) into which a slot insulation paper (6) can be positioned, and a punch (32) by means of which the slot insulation paper (6) can be pressed into the die (31), wherein the die (31) has a negative form (33) which is designed such that after forming • the slot insulation papers (6) have a substantially U-shaped cross-sectional contour, with a circumferentially extending base (7) from which a first free leg (8) and a second free leg (9) extend radially away from the base (7), and • the slot insulation papers (6) protrude axially from the stator slots (3) at at least one end face (10) of the stator (1 ) with a projection section (11 ) • in the overhang section (11 ) of the slot insulation papers (6) the circumferential distance (12) between the first free leg (8) and the second free leg (9) increases with increasing axial distance (13) viewed from a stator slot (3), wherein • the circumferential distance (12) increases such that an imaginary connecting line (14) of the first free leg (8) from its axial end (15) to the beginning of the overhang section (11) has an angle (16) of 30-50° to an axial extension axis (17) of the stator groove (3) and • an imaginary connecting line (18) of the second free leg (9) from its axial end (19) to the beginning of the overhang section (11) has an angle (20) of 30-50° to an axial extension axis (21) of the stator groove (3).

13. Manufacturing device for producing a stator for an electric machine with a forming tool for embossing a slot insulation paper, comprising a die into which a slot insulation paper can be positioned, and a punch by means of which the slot insulation paper can be pressed into the die, wherein the die has a negative form which is designed such that after forming • the slot insulation papers have an essentially U-shaped cross-sectional contour, with a radially extending base from which a first free leg and a second free leg extend tangentially away from the base, and • the slot insulation papers protrude radially from the stator slots with an overhang section on at least one circumferential surface of the stator, wherein • in the overhang section of the slot insulation papers, the circumferential distance between the first free leg and the second free leg increases with increasing radial distance when viewed from a stator slot, wherein • the circumferential distance increases so that an imaginary connecting line of the first free leg from its radial end to the beginning of the overhang section has an angle of 30-50° to a radial extension axis of the stator slot and an imaginary connecting line of the second free leg from its radial end to the beginning of the overhang section has an angle of 30-50° to a radial extension axis of the stator slot.

14. Manufacturing device according to claim 12 or 13, characterized in that the manufacturing device (40) has at least one hold-down device (36) by means of which the slot insulation paper (6) is held during embossing with two wings extending in the axial direction and projecting from the die (31). (34,35) is pressed against the die (31) or the manufacturing device has at least one hold-down device by means of which the slot insulation paper is pressed against the die during embossing with two wings extending in the tangential direction and projecting out of the die.

Images