Mechanical rotor design and assembly

Abstract

The invention relates to electric machines, in particular the structural nature of laminated rotor cores and the incorporation of magnetic material in laminated rotor cores for a rotor of an electric machine. A corresponding laminated rotor core for an electric machine comprises a magnetic pocket with magnetic material, which has radially outwardly and inwardly directed regions. Structural integration allows mechanical force deflection by directly abutting surfaces of the magnetic material and the regions of the laminated rotor core, wherein intermediate spaces separate the laminated rotor core from the magnetic material.

Description

17- February 2026 MOLÄBO GmbH M166314WO CKÄ / Wrd Mechanical rotor design and assembly Technical field

[0001] The present invention relates to the technical field of electrical machines, in particular the structural design of 5 rotor lamination packages and the installation of magnetic material into rotor lamination packages for a rotor of an electric machine. background

[0002] A general goal in the design of permanent magnet rotors for electric machines is to ensure that the rotors are mechanically and structurally stable, so that they can withstand the centrifugal forces generated at high speeds and be operated safely.

[0003] However, if the rotor of the electric machine has recesses for the permanent magnets, forming magnet pockets that contain the magnets, these recesses constitute a structurally incomplete part of the rotor lamination stack. This gap in the structure of the rotor lamination stack makes it mechanically less stable than if it were without this gap. Therefore, such rotor lamination stacks can only be operated at lower speeds with lower centrifugal forces. However, a lower speed leads to lower power output from the electric machine, which depends on both the speed and the torque of the electric machine.

[0004] This is further compounded by the fact that the magnets in their magnet pockets are subject to their own centrifugal forces during operation of the electric machine. These additional centrifugal forces are transferred to the portion of the lamination stack extending radially outwards from the magnets. This is because, in an in-rotor design, the five magnets are typically positioned towards the outer edge of the rotor, meaning close to or in the direction of the air gap between the rotor and stator of the electric machine. The web between the recess in the rotor lamination stack or the magnet pocket for the permanent magnets and the outer edge of the rotor along its circumference is therefore relatively thin. This is also because the rotor field, or air gap field, should be as strong as possible, which is why the magnets are usually arranged radially outwards and towards the stator.These relatively thin webs of the rotor lamination stack are structurally relatively weak and therefore usually represent the least mechanically stable part, or one of the least stable parts, of the rotor lamination stack. However, due to the arrangement of the permanent magnets in the magnet pockets and the additional centrifugal forces that act radially outwards from the magnets during operation, these relatively thin webs must simultaneously withstand the highest mechanical stresses in the rotor lamination stack.

[0005] To nevertheless provide electric machines with high rotational speeds and thus higher power output, which can withstand correspondingly higher centrifugal forces, it was known to leave continuous, uncut or unrecessed sections of the rotor lamination stack in the center of the magnet pockets. These sections stabilize the rotor's magnet pockets in the form of a continuous web, i.e., a structural bridge. Such a structural bridge connects a more stable area of ​​the rotor lamination stack, which in an inrunner rotor design is located radially inwards from the magnets or the magnet pocket towards the rotor axis, i.e., radially inwards, with the less stable area of ​​the rotor lamination stack, which has the relatively thin webs and is located radially outwards from the magnets or the magnet pocket towards the air gap field or stator.This structural bridge allows the more stable part of the rotor lamination stack to absorb some of the centrifugal forces emanating from both the less stable part of the stack itself and the magnets in the magnet pockets. Consequently, the portion of the centrifugal forces that the relatively thin webs of the rotor lamination stack have to bear is reduced.

[0006] Such a bridge thus causes the centrifugal forces generated in the magnet pockets to be redistributed to the structurally much more stable part of the rotor lamination stack and, in particular, to be largely diverted away from the thin, less stable outer webs in the air gap field. For these reasons, rotor areas with recesses, such as areas with magnet pockets in which permanent magnets are accommodated, pose particular mechanical challenges for the design of rotors of electric machines.

[0007] Furthermore, another general goal in the design of permanent magnet rotors for electric machines is to maximize the strength of the rotor magnetic field, among other things to achieve high power density and efficiency of the electric machine. The strength of the air-gap magnetic field generated by the rotor's permanent magnets is a crucial factor in the efficiency of an electric machine. Specifically, a stronger air-gap magnetic field leads to higher torque, resulting in increased power and efficiency. However, the previously described structurally stabilizing bridges of the rotor lamination stack create a kind of magnetic short circuit between the poles of the permanent magnets, causing these bridges to divert the magnetic field to locations other than the air gap of the electric machine.This reduces the portion of the magnetic field that is still effectively available to generate torque as a gap magnetic field. The bridges therefore lead to larger magnetic stray fields and smaller air gap magnetic fields. This causes a loss of efficiency as well as a loss of power density and torque density in the electric machine.

[0008] Further possibilities for integrating magnetic material into the rotor lamination stack of an electric machine are known from the prior art. For example, EP 3657638 Ai describes a rotor with magnets that can be arranged in pairs and in a V-shape along the circumference of the rotor lamination stack. To mount these magnets stably, a bridge, i.e., a structural bridge, is located between two magnets of a V-shaped pair, thereby connecting the radially outer and unstable part of the rotor lamination stack with the radially inner and more stable part.

[0009] Furthermore, EP 1456931 Ai describes how a magnet can be arranged in a magnet pocket. The magnet pocket, containing the magnets, abuts the rotor lamination stack directly at all four corners to clamp and secure the magnets within the pocket. Due to the contacts of the rotor lamination stack on all sides of the magnets, a material bridge forms around the corners or shoulders of the bar magnets, causing the magnetic field of the individual magnets to be short-circuited or redirected. This is also because structural bridges or webs remain between the individual magnets, connecting the radially outer and unstable part of the rotor lamination stack with the radially inner and more stable part. This web, combined with the contact of the rotor lamination stack on all sides or corners of the inserted magnets, creates a magnetic short circuit. [ooio] Both the design of EP 3657638 Ai and of EP 1456931 Ai consequently has the disadvantage that the web or structural bridge, which is usually formed from the material of the rotor lamination stack, can lead to a short circuit of the magnetic fields of the two magnets, which can result in a weakening of the effective rotor magnetic field. This negatively affects the performance of the electric machine, as the magnetic flux in the air gap between the rotor and stator of the electric machine is reduced.

[0011] To eliminate this disadvantage, the bridge between the magnets could be removed, thus preventing a short circuit of the magnetic field between the magnets of a magnet pair. However, this has the drawback that the entire centrifugal force exerted on a magnet during rotation of the rotor lamination stack must be absorbed by the outer lamination web of the rotor lamination stack. This means that this outer lamination web is subjected to high mechanical stress, especially at high speeds, which can lead to increased material wear and unwanted defects and deformations. Since it is advantageous to position magnets as far away from the center of rotation as possible on a rotor lamination stack due to the higher torque achievable, the edge region of a rotor lamination stack that lies radially outside the magnets is particularly thin, as is also the case in EP 1456931 Ai. Therefore, the increased stress in this area at high speeds is problematic.This applies regardless of whether the bridge between the magnets is removed or not. In both cases, this section of the rotor lamination stack limits the rotor's mechanical stability and simultaneously restricts the maximum speed and power at which the electric machine can operate. Conversely, if the magnets were positioned radially further inwards, the efficiency, torque, and power of the electric machine would decrease, which is disadvantageous.

[0012] Therefore, there is a need for a technical solution that simultaneously solves the problems described above related to mechanical stability and magnetic short circuits, without reducing power, torque, or speed. Such an electric machine would thus exhibit higher efficiency and operate mechanically stable even at high speeds and power levels. Therefore, the object of the present invention is to provide a rotor design that enables an efficient and mechanically stable electric machine. Summary

[0013] This problem is solved by claim 1. According to the present disclosure, a rotor lamination stack comprises a magnet pocket arranged in the rotor lamination stack; a first region of the rotor lamination stack arranged radially outward from the magnet pocket; a second region of the rotor lamination stack arranged radially inward from the magnet pocket; magnetic material arranged in the magnet pocket; and a structural integration of the magnetic material into the rotor lamination stack, comprising: a first directly adjacent arrangement of at least one first surface of the magnetic material and at least one surface of the first region of the rotor lamination stack; a second directly adjacent arrangement of at least one second surface of the magnetic material and at least one surface of the second region of the rotor lamination stack;and spaces formed in areas of the magnetic pocket located outside the directly adjacent first and second arrangements and between the rotor lamination stack and the magnetic material, wherein the rotor lamination stack is spatially separated from the magnetic material in the spaces; and wherein the structural integration of the magnetic material into the rotor lamination stack enables a mechanical force redirection from the first area of ​​the rotor lamination stack through the at least one surface of the first area of ​​the rotor lamination stack, the at least one first surface of the magnetic material, the magnetic material, the at least one second surface of the magnetic material, and the at least one surface of the second area of ​​the rotor lamination stack to the second area of ​​the rotor lamination stack.

[0014] The advantages achieved by the invention lie in the reduction of the stray field of the rotor magnets, since the structural integration of the magnetic material into the rotor lamination stack eliminates the need for a web or mechanical bridge. This structural integration alone allows the forces to be redirected from a radially outer region of the rotor lamination stack to the radially inner region. This structural integration achieves this by the direct contact between the magnetic material and the rotor lamination stack at only two points, while gaps exist between these contact points, separating the rotor lamination stack and the magnetic material. Consequently, there is no continuous bridge of magnetic material that spans all sides or at least both magnetic poles of the magnetic material, thereby short-circuiting the magnetic field.This increases the rotor-side amplitude of the magnetic field in the air gap between the rotor and stator, leading to an increase in the efficiency and torque density of the electric machine. "Directly in contact" means that there is mechanical contact at these points. Manufacturing tolerances or other deviations that deviate, at least partially, from "exact" or "continuous" contact are nevertheless included. This is because it refers to such mechanical contact that can effect force transmission at the directly contacting points, which can still be ensured by minor deviations within the directly contacting arrangements. This definition also applies to all other locations where directly contacting configurations or arrangements are mentioned.

[0015] Furthermore, the advantageous arrangement of the magnets within the rotor lamination stack improves mechanical stability because the centrifugal forces acting on the magnetic material and the first layer of the rotor lamination stack are redirected to the second layer, thus reducing the mechanical stress on the outer layer. This redirection is achieved by the advantageous arrangement of the magnets within the rotor lamination stack, which causes the centrifugal force to exert a torque on the magnets. This torque, similar to the principle of a lever, causes the magnets to deflect the centrifugal force from the outer layer of the rotor lamination stack to the inner layer. This results in reduced mechanical stress on the relatively thin outer layer. Consequently, wear on the rotor lamination stack or the magnet material, as well as the risk of defects, is reduced, particularly during operation at high speeds.

[0016] The lamination geometry around the magnets can be designed such that the centrifugal force of the lamination area in the center of a magnetic pole of the electric machine's rotor is redirected via the magnetic material to the lamination area between two magnetic poles of the rotor and reliably absorbed there. The mechanical strength of the magnetic material must be considered, as magnets, in most cases, cannot withstand tension or bending, but can withstand compression. Therefore, the structural integration can clamp the magnetic material between the first and second adjacent arrangements. This clamping ensures that the rotor lamination stack areas exert pressure on the magnetic material when centrifugal forces are generated.

[0017] The structural integration can also be referred to as an enveloping structure. In a preferred embodiment, it can be designed in the form of non-continuous structural support surfaces in the rotor lamination stack and on the magnet pockets. These support surfaces can be located at two points on the magnetic material and abut each other at these locations. First, at or near an area located in the center of the magnet pocket, that is, at or facing the center of the rotor's magnetic poles. In this area, the point where the support surfaces of the rotor lamination stack and the magnetic material abut each other in the magnet pocket can be arranged radially outwards. Second, at or near an area located on an outer side of the magnet pockets, that is, at or facing the area between two of the rotor's magnetic poles. These and other preferred embodiments will be explained in more detail below.Since the first point is arranged radially outwards and the second point radially inwards, and thus crosswise, the structural integration can wedge or lock the magnetic material within the rotor lamination stack. This wedge or lock allows centrifugal forces to be diverted away from the thin and unstable air-gap-oriented edge regions or ribs of the rotor lamination stack. The structural integration can act as a kind of counter-lock or counter-interlock, exerting pressure on both ends of the magnetic material. This allows the magnetic material to transfer or redirect forces from radially outwards to radially inwards between the two rotor lamination stack regions. This prevents magnetic short circuits in the magnetic fields, advantageously deflects the centrifugal forces, and thus reduces them at the otherwise highly stressed areas.

[0018] Further advantageous embodiments of the invention are specified in the dependent claims.

[0019] In one embodiment, at least one surface of the first and / or second region of the rotor lamination stack is arranged on at least one projection of the rotor lamination stack. In a further embodiment, at least two surfaces of the at least one projection can face each other or be aligned substantially parallel to each other. In a further embodiment, the at least two surfaces of the at least one projection can face the first and / or second surface of the magnetic material or be aligned substantially parallel to each other.

[0020] Providing a protrusion segments the magnetic material within the magnet pocket. This has the advantage that the force transmitted via the magnet acts on two surfaces, thus achieving a better distribution of the mechanical load across the second area of ​​the rotor lamination stack. A protrusion can also facilitate the assembly and maintenance of the rotor lamination stack by providing clear positioning points and simplifying component handling. Furthermore, a parallel alignment of the surfaces ensures a uniform pressure distribution on the magnetic material, reducing the risk of cracks or fractures and thus further improving the durability and wear resistance of the magnetic material.

[0021] In one embodiment, the at least one magnetic pocket is a continuous recess in the rotor lamination stack.

[0022] Providing the magnetic pocket as a continuous recess prevents or reduces the occurrence of magnetic short circuits in the magnetic field of the magnetic material. This increases the magnetic flux in the air gap between the rotor and stator, leading to an increase in the efficiency and torque density of the electric machine.

[0023] In one embodiment, the at least one magnetic pocket comprises one magnet or at least two separate magnets.

[0024] Providing a smaller number of magnets in a magnet pocket increases the amount of magnetic material that can be arranged in the pocket and thus in a magnetic pole of the rotor. This is because the fill factor of the magnetic material in the magnet pocket can increase the fewer structurally different magnets are arranged within it. Due to the resulting higher air-gap magnetic field, the efficiency and torque density of the electric machine can be advantageously increased.

[0025] In one embodiment, the magnetic material has one or more bar magnets, and the one or more bar magnets have a straight, bent, or kinked shape.

[0026] By arranging bar magnets with straight, curved, or bent shapes within the magnet pocket, it is possible to fill even a relatively long, continuous magnetic pocket with just one or a few different magnets. This increases the fill factor of the magnetic material in the magnet pocket for a magnetic pole in the rotor, which, due to the resulting higher air-gap magnetic field, can advantageously increase the efficiency and torque density of the electric machine. Furthermore, a suitable shape of the magnetic material allows for flexible adaptation to the specific geometric requirements of the rotor lamination stack, leading to improved integration and mechanical stability. Additionally, curved or bent magnets can help to distribute mechanical stress more evenly, thus improving the structural integrity of the rotor.

[0027] In one embodiment, the structural integration of the magnetic material into the rotor lamination stack has a positive-locking, force-locking or material-locking connection between at least two or more of the following locations in the rotor lamination stack: the at least one first surface of the magnetic material, the at least one second surface of the magnetic material, the surface of the first region of the rotor lamination stack and the surface of the second region of the rotor lamination stack.

[0028] The form-fit, force-fit, or material-fit arrangement of the structural integration exerts pressure on the magnetic material. This pressure prevents play between the magnetic material and the rotor lamination stack, thus reducing wear effects and ensuring the magnets are securely positioned even at high rotor speeds. Furthermore, many magnet types are only suitable for mechanical loads caused by pressure, but not by tensile or bending loads, which also increases structural stability and compatibility with various magnetic materials. In addition, the interlocking arrangement enables optimal force transmission of centrifugal forces from the first to the second layer of the rotor lamination stack.

[0029] In one embodiment, the structural integration of the magnetic material into the rotor lamination stack comprises: a directly adjacent arrangement of the first and a third surface of the magnetic material and of two surfaces of the first region of the rotor lamination stack; a directly adjacent arrangement of the second and a fourth surface of the magnetic material and of two surfaces of the second region of the rotor lamination stack.

[0030] This results in the segmentation of the magnetic material at two edges. This double segmentation optimizes the distribution of the transmitted centrifugal forces, as force can be transferred from the first area to the magnetic material at the first and third surfaces, and force can also be transferred from the magnetic material to the second area at the second and fourth surfaces. This leads to a better distribution of the transmitted forces and a reduction in stress on the magnetic material, since lower forces act on multiple surfaces instead of a single high force. Furthermore, such segmentation of the magnetic material can help optimize the rotor's magnetic properties by enabling finer tuning of the magnetic field.This can be particularly advantageous when different magnetic materials or strengths are used to achieve specific magnetic properties.

[0031] In one embodiment, the following differ from each other: the two surfaces of the first region of the rotor lamination stack; and / or the first and third surfaces of the magnetic material; and / or the second and fourth surfaces of the magnetic material; and / or the two surfaces of the second region of the rotor lamination stack; and / or the first and third surfaces of the magnetic material from the second and fourth surfaces of the magnetic material.

[0032] By appropriately differentiating the surfaces, the distribution of the transmitted centrifugal forces can be optimized. This is because different locations of the magnetic material across the different surfaces result in a reduction of stress on the magnetic material, as lower forces act on these areas. A further advantage is the potential reduction of magnetic short circuits, since the differentiated surfaces allow for more precise control of the magnetic flux. This can lead to an increase in the efficiency and torque density of the electric machine, as the air gap field can be improved.

[0033] In one embodiment, the first surface of the magnetic material is opposite the second surface of the magnetic material at an intermediate rod-shaped section of the magnetic material or is oriented substantially parallel to each other; and the rod-shaped section of the magnetic material has a straight, curved or bent shape.

[0034] This opposing arrangement of the first and second surfaces of the magnetic material improves cross-locking or counter-locking of the magnetic material. This results in a more stable structural integration of the magnetic material within the rotor lamination stack.

[0035] In one embodiment, the at least one magnetic pocket is a one-piece and continuous opening in the rotor lamination stack, containing only materials that differ from the material of the rotor lamination stack.

[0036] Providing the opening as a single, continuous opening and avoiding material from the rotor lamination stack in the opening helps to prevent magnetic short circuits between poles of the magnetic material, which in turn leads to an increase in the efficiency and torque density of the electric machine.

[0037] In one embodiment, the first region of the rotor lamination stack is located in the middle of a rotor pole of the rotor lamination stack, which is formed by the magnetic material, and the second region of the rotor lamination stack is located between two rotor poles of the rotor lamination stack.

[0038] This arrangement improves the leverage of the magnetic material. Because when the magnetic material is encased by the first and second layers in this way, the centrifugal force during operation can be optimally transferred from the first layer, through the magnetic material, to the second layer.

[0039] In one embodiment, the spaces between are at least partially filled with a non-magnetic material, preferably with a paramagnetic or diamagnetic material, even more preferably with air and / or non-magnetic bonding agents such as adhesives or resins.

[0040] This can prevent magnetic short circuits and thus increase the magnetic flux in the air gap between the rotor and stator of the electric machine. Furthermore, filling the gaps can improve the structural integration of the magnetic material into the rotor lamination stack. This provides better protection against unwanted slippage and wear. Appropriate filling of the gaps can also further secure or clamp the magnets in their pockets.

[0041] In one embodiment, the magnetic material has a tapered section that divides the magnetic material into at least two segments, wherein the at least two segments are separate magnetic segments of different magnets or structurally connected magnetic segments of a single magnet, and wherein each segment has its own structural integration into the rotor lamination stack, which enables the transmission of centrifugal forces from the first area of ​​the rotor lamination stack through the magnetic material of each segment to the second area of ​​the rotor lamination stack.

[0042] As described above, the segmentation of the magnetic material leads to improved force distribution and reduced mechanical stress on the magnetic material, thus reducing wear and tear on both the rotor lamination stack and the magnetic material. Furthermore, the structural integration of the magnetic material into the rotor lamination stack can be improved. This allows the electric machine to be operated safely at even higher speeds and centrifugal forces, which advantageously increases the power and torque density of the electric machine.

[0043] In one embodiment, the rotor lamination stack without the magnetic material has at least one section which, viewed from an axis of rotation of the electric machine, has a radius larger than the corresponding radius of the rotor lamination stack, wherein the rotor lamination stack with the magnetic material in the magnet pocket has the radius of the rotor lamination stack throughout.

[0044] This arrangement ensures that, firstly, the magnet is securely clamped in the magnet pocket segment, and secondly, that the power transmission from the first area to the second area is reliably ensured even in limit load operating ranges of the electric machine. Simultaneously, the rotor lamination stack is prestressed so that the mechanical stress vector counteracts the centrifugal force. This structural prestressing improves the structural integration of the magnetic material into the rotor lamination stack. As a result, the electric machine can be operated safely at even higher speeds and centrifugal forces, which advantageously increases the power and torque density of the electric machine.

[0045] The preceding summary serves to present some embodiments in order to provide a basic understanding of the aspects of the subject matter described herein. Accordingly, the features described above should not be interpreted as limiting the scope of the subject matter described herein. Furthermore, the above and / or further embodiments can be combined or incorporated in any suitable combination. Additional features, aspects, and advantages of the subject matter described herein will become apparent from the following detailed description, the drawings, and the claims. Brief description of the characters

[0046] To describe how the embodiments of the invention described above are implemented, and to define other advantages and features of the disclosure, a more detailed description is provided below. The accompanying drawings illustrate aspects of the description, with identical numbers denoting identical elements. Under the understanding that these drawings represent exemplary embodiments of the invention and are therefore not to be considered as limiting in scope, the embodiments are further explained below with additional details by means of the accompanying drawings.

[0047] Figure 1 shows the structure of a conventional rotor lamination stack in the stator of an electric machine as known from the prior art.

[0048] Figure 2 shows an improved design of a rotor lamination stack in the stator of an electric machine.

[0049] Figure 3 shows the result of a simulation of the mechanical stress distribution along the rotor lamination stack when centrifugal forces act on the rotor lamination stack.

[0050] Figure 4 shows a further improved structure of a rotor lamination stack according to the present disclosure.

[0051] Figure 5 shows the result of a simulation of the mechanical stress distribution along the rotor lamination stack when centrifugal forces act on the rotor lamination stack in the improved setup according to the present disclosure.

[0052] Figures 6 to 12 show exemplary arrangements according to the present revelation. Detailed description

[0053] Figure 1 shows the structure 100 of a conventional rotor lamination stack 110 in the stator 120 of an electric machine as known from the prior art.

[0054] The figure shows a quarter circle of the circular rotor 110 within the stator 120. The stator 120 contains coils 122, which function as electromagnets and can be controlled with a three-phase current, thus inducing a rotating magnetic field inside the stator 120.

[0055] Within the stator 120 is the rotor lamination stack 110, which is rotatably mounted in the stator. Magnetic material in the form of permanent magnets 112 is mounted in magnet pockets 116 within the rotor lamination stack 110. The magnetic field lines 118 of these magnets run between the magnetic north and south poles. The magnet pockets 116 are preferably larger than the permanent magnets 112, so that a space, i.e., a cavity, is created at the ends of the permanent magnets, in which a non-magnetic material (for example, air) is located. When a three-phase current is applied to the coils 122 of the stator 120, an electromagnetic field is induced by the coils. This causes the permanent magnets 112 to align themselves in the magnetic field induced by the coils 122. As a result, the rotor lamination stack 110 begins to rotate, exerting a radially outward centrifugal force on the permanent magnets 112.

[0056] To compensate for the centrifugal force, it is known to arrange a bridge 114 between two permanent magnets 112. This bridge 114 compensates for the centrifugal force acting on the permanent magnets 112, as it creates a mechanical connection between the radially outward-facing, less stable first rotor lamination stack area and the radially inward-facing, more stable second rotor lamination stack area. This mechanical connection allows centrifugal forces acting on the radially outer and less stable first rotor lamination stack area to be at least partially redirected to the radially inner and more stable second part of the rotor lamination stack and thus be absorbed by it.

[0057] However, the bridge 114, which is made of the same material as the rotor lamination stack, has the disadvantage that it leads to magnetic short circuits, which compromise the resulting magnetic field of the permanent magnets 112, thus impairing the efficiency and torque density of the electric machine.

[0058] Figure 2 shows an improved design 200 of a rotor lamination stack 210 in the stator 220 of an electric machine. This design eliminates the disadvantage just described, since no bridge 114 is placed between the permanent magnets 112, as shown in Figure 2.

[0059] The improved design also consists of a stator 220 with coils 222 that generate a rotating electromagnetic field via a three-phase current, as described in connection with Figure 1. Within the stator 220 is also a rotor lamination stack 210 in which magnetic material in the form of permanent magnets 212 is arranged, generating a magnetic field according to the magnetic field lines 218 shown. However, since the improved design 200 does not have a bridge between the permanent magnets 212, but instead an intermediate space 216 filled with a non-magnetic material (for example, air), a magnetic short circuit does not occur between the permanent magnets 212 as described in connection with Figure 1.

[0060] However, this has the disadvantage of increased mechanical stress on the outer surface of the rotor lamination stack 210, as shown in Figure 3.

[0061] Figure 3 shows the result of a simulation of the stress distribution along the rotor lamination stack 300 when centrifugal forces act on the rotor lamination stack 300.

[0062] The rotor lamination stack 300 shown in Figure 3 is structurally essentially identical to the rotor lamination stack 210 shown in Figure 2. A computer simulation was used to determine which areas of the rotor lamination stack 300 are subjected to which mechanical stresses during rotation at a practical speed due to centrifugal forces exerted, for example, on the permanent magnets 310 and the rotor lamination stack 300. The corresponding stress values ​​are plotted in grayscale according to legend 320. The simulation results show that most of the rotor lamination stack 300 is subject to only low mechanical stress, so that the mechanical stress (referred to as stress in Figure 3) is in the range between 0 and 112.5 MPa. Areas with somewhat higher stress, on the order of 150 MPa, are found in the outer regions of the rotor lamination stack 300.The highest mechanical stress is found at locations 330 and 340, where the magnet pockets 316 border the outermost region of the rotor lamination stack 300. In the present simulation, these locations 330 and 340 are subjected to mechanical stresses of up to 783.5 MPa. This high mechanical stress at these locations can be explained in particular by the fact that the centrifugal force acting on the permanent magnets, as well as on the entire triangular area of ​​the rotor lamination stack enclosed by the magnet pocket 316, must be absorbed by the relatively thin rotor lamination stack regions 330 and 340. Thus, this radially outward-facing rotor lamination stack region is a first unstable region located in the center of the rotor pole formed by the permanent magnets 310 and extending radially outward between the two relatively thin rotor lamination stack regions 330 and 340.In contrast, the rotor lamination stack area located next to the permanent magnets 310 (and thus between two rotor poles, not shown in Figure 3) together with the rotor lamination stack area that is directed radially inwards from the magnet pockets, is a more stable area of ​​the rotor lamination stack that is subject to lower mechanical loads.

[0063] The high stress at points 330 and 340 is particularly disadvantageous because the rotor lamination stack 300 is especially narrow there, making the rotor lamination stack 300 particularly susceptible to deformation and wear.

[0064] Figure 4 shows a further improved design of a rotor lamination stack 400 that solves this problem.

[0065] As shown in Figure 4, the rotor lamination stack 400 comprises a magnet pocket 416, which includes an inner region 422 and two outer regions 418 and 420. Magnetic material, such as permanent magnets 412 and 414, is arranged between the inner and outer regions of the magnet pocket. The rotor lamination stack 400 is divided by the magnet pocket 416 into a first region 430, which is arranged radially outwards from the magnet pocket 416 within the rotor lamination stack 400, and into a second region 440, which is arranged radially inwards from the magnet pocket 416 within the rotor lamination stack 400. Preferably, the magnets 412, 414 are arranged such that a first magnetic pole of the magnetic material is arranged on a side facing the first area 430 of the rotor lamination stack 400 and a second magnetic pole of the magnetic material is arranged on a side facing the second area 440 of the rotor lamination stack 400.

[0066] Furthermore, the rotor lamination stack 400 comprises a structural integration of the magnetic material, which includes a first directly adjacent arrangement 432 of at least one first surface of the magnetic material 412, 414 and at least one surface of the first region 430. The structural integration of the magnetic material also includes a second directly adjacent arrangement 442 of at least one second surface of the magnetic material 412, 414 and at least one surface of the second region 440 of the rotor lamination stack. The structural arrangement also includes gaps in the regions of the magnet pocket 416, which are located outside the directly adjacent first and second arrangements 432, 442 and between the rotor lamination stack 400 and the magnetic material 412, 414.Figure 4 shows, by way of example, a gap 422, which is arranged in the radially inner region of the magnetic pocket 416, and gaps 418 and 420, which are arranged in the radially outer region of the magnetic pocket 416. As shown by way of example in Figure 4, the gaps 418 and 420 are located next to the second directly adjacent arrangement 442, while gap 422 is located next to the first directly adjacent arrangement 432. Additional gaps may also be located along the longer sides of the magnetic material, but these are not shown in Figure 4. These gaps can be very narrow, which is why they are not clearly visible in Figure 4, and can ensure that the magnetic material 412, 414 does not contact the rotor lamination stack at any point except at the directly adjacent arrangements 432, 442.This avoids magnetic short circuits between magnetic material 412, 414 and the rotor lamination stack, as the contacting surfaces can be reduced to a minimum.

[0067] When the rotor lamination stack 400 is set into rotation, centrifugal forces Fi, F2 act on the magnetic material 412, 414 and on the first area 430 of the rotor lamination stack 400. The resulting total force is the vector F totThe arrangement shown in Figure 4 enables the structural integration of the magnetic material 412, 414 to mechanically redirect the force from the first region 430 of the rotor lamination stack 400, through the first directly adjacent arrangement 432, which comprises at least one surface of the first region 430 of the rotor lamination stack 400 and at least one first surface of the magnetic material 412, 414, via the magnetic material 412, 414 to the second directly adjacent arrangement 442, which comprises at least one surface of the second region 440 of the rotor lamination stack 400 and at least one second surface of the magnetic material 412, 414, and thus onto the second region 440 of the rotor lamination stack 400. The directly adjacent arrangements 432, 442 can each also be connected by more than one surface of the magnetic material 412, 414 and / or of the first or second region. 430, 440 of the rotor lamination stack 400 are formed.

[0068] In the embodiment shown in Figure 4, the mechanical force redirection is achieved by positioning the directly adjacent arrangements 432 and 442 diagonally opposite each other on the magnetic material 412, 414. This allows the centrifugal force to be redirected from the first area 430 via the magnetic material 412, 414 to the second area 440 through the first directly adjacent arrangement 432. The magnetic material 412, 414 acts here like a kind of locking lever, transferring the force to the second directly adjacent arrangement 442 and thus ensuring the force transmission to the second area.Since the centrifugal force acts radially outwards and engages at the points where the arrangements directly abut each other, the magnetic material 412, 414 has a mechanically interlocking effect, ensuring that the first section 430 of the rotor lamination stack 400 is securely positioned even at high rotational speeds and is also mechanically relieved by this arrangement. Furthermore, this arrangement ensures that the magnetic material 412, 414 is subjected to compressive stress rather than tensile stress or similar forces, which, as already explained, represents a significantly more stable type of load for most types of magnetic material. Although in the embodiment described here as an example the directly abutting arrangements 432, 442 are diagonally opposite each other, other embodiments are possible in which the structural integration is designed differently, for example, when using magnets with a different basic shape than the bar magnets used here.Even then, a corresponding force redirection with a blocking effect is possible. Further exemplary designs are described elsewhere in this revelation.

[0069] To prevent magnetic short circuits, the first surface of the first area, which in the first directly adjacent arrangement 432 abuts the first surface of the magnetic material 412, 414, can preferably not be designed as a ridge, but merely as a projection, as shown in Figure 4, against which a portion of the surface of the magnetic material 412, 414 facing inwards towards the rotor pole abuts. This ensures that a portion, preferably a predominant portion, of the previously described space 422 between the magnetic material 412, 414 is filled with a non-magnetic substance (for example, air), thus preventing magnetic short circuits in this area.

[0070] Furthermore, the magnetic pocket 416 can be a continuous recess in the rotor lamination stack 400. This helps to avoid the magnetic short circuits described above. It also facilitates efficient manufacturing of the rotor lamination stack 400, both in terms of material consumption and complexity.

[0071] Furthermore, the magnetic pocket can contain one or more separate magnets. Additionally, the magnetic material can include one or more bar magnets with a straight, curved, or bent shape. Both of these features allow for the individual adaptation of the magnetic material to the structural, mechanical, and electrical requirements of the electric machine. This also enables greater flexibility in the manufacturing of the electric machine.

[0072] The structural integration of the magnetic material 412, 414 into the rotor lamination stack 400 can be a form-fit, force-fit or material-fit connection between at least two or more of the at least one first surface of the magnetic material 412, 414, the at least one second surface of the magnetic material 412, 414, the surface of the first area 430 of the rotor lamination stack 400, and the surface of the second area 440 of the rotor lamination stack 400.

[0073] A positive-locking, force-locking or material-locking connection can prevent the mobility of the magnetic material 412, 414 in the rotor lamination stack 400, so that wear phenomena, for example due to friction of the magnetic material 412, 414 on the material of the rotor lamination stack 400, can be avoided or reduced.

[0074] Centrifugal forces can be generated by rotation of the rotor lamination stack 400, whereby the structural integration of the magnetic material 412, 414 into the rotor lamination stack 400 enables a transfer of the centrifugal forces from the first area 430 of the rotor lamination stack 400 through the magnetic material 412, 414 to the second area 440 of the rotor lamination stack 400.

[0075] The first surface of the magnetic material 412, 414 can be opposite the second surface of the magnetic material 112, 114 in an intervening rod-shaped section of the magnetic material 112, 114 or substantially parallel to each other, and the rod-shaped section of the magnetic material can have a straight, bent or kinked shape.

[0076] Furthermore, a first magnetic pole of the magnetic material 412, 414 can be arranged on a side facing the first area 430 of the rotor lamination stack 400 and a second magnetic pole of the magnetic material 412, 414 can be arranged on a side facing the second area 440 of the rotor lamination stack 400.

[0077] Furthermore, the magnetic pocket 416 can be a one-piece and continuous opening in the rotor lamination, containing only materials that differ from the material of the rotor lamination stack 400. Preferably, the magnetic pocket 416 contains only magnetic material and a non-magnetic substance such as air. This can prevent the occurrence of a magnetic short circuit, thus increasing the effective magnetic flux in the air gap between the rotor lamination stack 400 and a stator of an electric machine, which allows the machine to be operated more efficiently and with increased torque density.

[0078] In some embodiments, the first region 430 of the rotor lamination stack 400 can be located in the middle of a rotor pole of the rotor lamination stack 400, which is formed by the magnetic material 412, 414, and the second region 440 of the rotor lamination stack 400 can be located between two rotor poles of the rotor lamination stack 400.

[0079] The spaces 418, 420, 422 can be at least partially filled with a non-magnetic material, preferably with a paramagnetic or diamagnetic material, even more preferably with air and / or non-magnetic connecting materials such as adhesives or resins.

[0080] Figure 5 shows the result of a simulation of the stress distribution along the rotor lamination stack 500 when centrifugal forces act on the rotor lamination stack 500 in the improved setup as described in connection with Figure 4.

[0081] The rotor lamination stack 500 shown in Figure 5 is structurally essentially identical to the rotor lamination stack 400 shown in Figure 4. A computer simulation was used to determine which areas of the rotor lamination stack 500 are subjected to which mechanical stresses during rotation at a practical speed due to centrifugal forces exerted on the permanent magnets 512 and the rotor lamination stack 500 itself, particularly on the first area 530. The corresponding stress intensities are plotted in grayscale according to the legend 520. The simulation results show that most of the rotor lamination stack 500 is subjected to essentially uniform mechanical stresses, resulting in mechanical stresses in the range of 0 to 100 MPa. Areas with somewhat higher stresses, on the order of approximately 130 MPa, are found throughout the outer section of the rotor lamination stack 500.

[0082] The highest mechanical stresses occur at locations 530 and 540, where the magnet pocket 516 borders the outermost area of ​​the rotor lamination stack 500. However, in the present simulation, these locations 530 and 540 are only subjected to mechanical stresses up to 235 MPa.

[0083] Compared to the simulation of the setup described in conjunction with Figures 2 and 3, the mechanical stress can be reduced to approximately one-third of its original value by the improved design of the rotor lamination stack as described in Figure 4. Simultaneously, the mechanical stress in the radially inner part of the rotor lamination stack increases because the centrifugal forces are redirected to the second area of ​​the rotor lamination stack via the first directly adjacent arrangement, the magnetic material, and the second directly adjacent arrangement. Since the forces and loads are thus distributed more evenly over the structurally much larger second area 530 of the rotor lamination stack 500, the peak mechanical load on the rotor lamination stack can be significantly reduced. In this way, deformations and wear, particularly at points 530 and 540, can be avoided.Furthermore, this allows the rotor of the electric machine to be operated at significantly higher speeds without exceeding its maximum mechanical load capacity. This, along with the avoidance of magnetic short circuits, contributes to the increased efficiency, torque density, and performance of the electric drive.

[0084] Figure 6 shows another embodiment according to the present disclosure.

[0085] As shown in Figure 6, the rotor lamination stack 600 comprises a magnet pocket 616, which includes an inner region 622 and two outer regions 618 and 620. Magnetic material, for example in the form of two permanent magnets 612 and 614, is arranged between the inner and outer regions of the magnet pocket 616. The rotor lamination stack 600 is divided by the magnet pocket 616 into a first region 630, which is arranged radially outward from the magnet pocket 616 within the rotor lamination stack 600, and into a second region 640, which is arranged radially inward from the magnet pocket 616 within the rotor lamination stack 600.

[0086] Furthermore, the rotor lamination stack 600 comprises a structural integration of the magnetic material, which includes a first directly adjacent arrangement 632 of at least one first surface of the magnetic material 612, 614 and at least one surface of the first region 630. The structural integration of the magnetic material also includes a second directly adjacent arrangement 642 of at least one second surface of the magnetic material 612, 614 and at least one surface of the second region 640 of the rotor lamination stack. The structural arrangement also includes gaps in the regions of the magnet pocket 616, which are located outside the directly adjacent first and second arrangements 632, 642 and between the rotor lamination stack 600 and the magnetic material 612, 614.Figure 6 shows, by way of example, a gap 622, which is arranged in the radially inner region of the magnetic pocket 616, and gaps 618 and 620, which are arranged in the radially outer region of the magnetic pocket 616. As shown by way of example in Figure 6, the gaps 618 and 620 are located next to the second directly adjacent arrangement 642, while gap 622 is located next to the first directly adjacent arrangement 632. Additional gaps may also be located along the longer sides of the magnetic material, but these are not shown in Figure 6. These gaps can be very narrow, which is why they are not clearly visible in Figure 6, and can ensure that the magnetic material 612, 614 does not contact the rotor lamination stack at any point except at the directly adjacent arrangements 632, 642.This avoids magnetic short circuits between magnetic material 612, 614 and the rotor lamination stack, as the contacting surfaces can be reduced to a minimum.

[0087] When the rotor lamination stack 600 is set into rotation, centrifugal forces Fi, F2 act on the magnetic material 612, 614. The arrangement shown in Figure 6 allows the structural integration of the magnetic material 612, 614 to enable a mechanical force redirection from the first region 630 of the rotor lamination stack 600, through the first directly adjacent arrangement 632, which comprises at least one surface of the first region 630 of the rotor lamination stack 600 and at least one first surface of the magnetic material 612, 614, via the magnetic material 612, 614 to the second directly adjacent arrangement 642, which comprises at least one surface of the second region 640 of the rotor lamination stack 600 and at least one second surface of the magnetic material 614, 614, and thus onto the second region 640 of the rotor lamination stack 600.The directly adjacent arrangements 632, 642 can each also be formed by more than one surface of the magnetic material 612, 614 and / or of the first or second area 630, 640 of the rotor lamination stack 600.

[0088] In the embodiment shown by way of example in Figure 6, the mechanical force redirection is made possible by the diagonal positioning of the directly adjacent arrangements 632 and 642 on the permanent magnets 612, 614. In this way, the centrifugal force can be redirected from the first area 630 via the magnetic material 612, 614 to the second area 640 through the first directly adjacent arrangement 632. The magnetic material 612, 614 acts here like a kind of locking lever, which transmits the force to the second directly adjacent arrangement 642, thus ensuring the force transmission to the second area.Since the centrifugal force acts radially outwards and engages at the points where the arrangements directly abut each other, the magnetic material 612, 614 has a mechanically interlocking effect, ensuring that the first section 630 of the rotor lamination stack 600 is securely positioned even at high rotational speeds and is also mechanically relieved by this arrangement. Furthermore, this arrangement ensures that the magnetic material 612, 614 is subjected to compressive stress rather than tensile stress or similar forces, which, as already explained, represents a significantly more stable type of load for most types of magnetic material. Although in the embodiment described here as an example the directly abutting arrangements 632, 642 are diagonally opposite each other, other embodiments are possible in which the structural integration is designed differently, for example, when using magnets with a different basic shape than the bar magnets used here.Even then, a corresponding force redirection with a blocking effect is possible. Further exemplary designs are described elsewhere in this revelation.

[0089] To prevent magnetic short circuits, the first surface of the first area, which in the first directly adjacent arrangement 632 abuts the first surface of the magnetic material 612, 614, can preferably not be designed as a ridge, but merely as a projection, as shown in Figure 6, against which a portion of the inwardly directed surface of the magnetic material 612, 614 rests. This ensures that a portion, preferably a predominant portion, of the space 622 between the magnetic material 612, 614 is filled with a non-magnetic substance (for example, air), thus preventing magnetic short circuits in this area.

[0090] The preferred design options described in connection with Figure 4 are also applicable in connection with the embodiment shown in Figure 6.

[0091] Furthermore, the additional design options described in connection with Figures 4 to 5 are also applicable to the embodiment of Figure 6.

[0092] Figure 7 shows another embodiment according to the present disclosure.

[0093] According to Figure 7, the structure of the rotor lamination stack 700 essentially corresponds to the embodiment described in Figure 6. Thus, the rotor lamination stack according to Figure 7 also comprises a magnetic pocket 716, which includes an inner region 722 and two outer regions 718 and 720, wherein magnetic material 712, 714 is arranged between the inner and outer regions of the magnetic pocket 716, a first directly adjacent arrangement 732 of at least one first surface of the magnetic material 712, 714 on at least one surface of a first region 730 of the rotor lamination stack 700, and a second directly adjacent arrangement 742 of at least one first surface of the magnetic material 712, 714 on at least one surface of a second region 740 of the rotor lamination stack 700. The preferred design options described in connection with Figures 4 and 6 are also applicable in connection with the embodiment shown in Figure 7.

[0094] According to Figure 7, the rotor lamination stack further comprises a bore or recess 750 into which, for example, a screw, bolt, or the like can be axially inserted. This can serve as a mechanical suspension for the first area 730, via which centrifugal forces from the first area 730 can be absorbed and redirected via the screw, bolt, or the like to another area, such as the second area 740. Additionally, a mechanical connection, for example by means of a rod or the like, can be established between the two sections 730 and 740. This allows for at least partial or additional force redirection at the axial ends of the rotor lamination stack without creating a magnetic short circuit. This can lead to further stabilization of the rotor lamination stack and to a reduction of the centrifugal force absorbed by the magnetic material 712, 714 in the magnet pocket 716. This results in additional mechanical relief of the first section 730, in particular the relatively thin edge regions of the rotor lamination stack 700, and of the magnetic material 712, 714 in the magnet pocket 716.

[0095] Furthermore, the additional design options described in connection with Figures 4 to 6 are also applicable to the embodiment of Figure 7.

[0096] Figure 8 shows another embodiment according to the present disclosure.

[0097] According to Figure 8, the rotor lamination stack 800 includes a magnetic pocket 816, which divides the rotor lamination stack into a first region 830, located radially outside the magnetic pocket 816, and a second region 840, located radially inside the magnetic pocket 816. Magnetic material of any shape can be arranged in the magnetic pocket (not shown in Figure 8).

[0098] In the embodiment according to Figure 8, the rotor lamination stack also includes a projection 860 that extends into the magnet pocket 816 and is suitable for coming into contact with at least one surface of a magnetic material located in the magnet pocket 816. Preferably, the projection 860 is located on a side of the magnet pocket 816 facing the second region 840. However, other embodiments in which the projection 860 is located in other positions are also possible. Preferably, the projection 860 is made of the same material as the rotor lamination stack 800; however, in other embodiments, the projection 860 can be made of other materials, e.g., non-magnetic materials.

[0099] Magnetic material can be inserted into the magnetic pocket 816. This material is preferably shaped such that it directly abuts at least one surface 832 of the first region 830, as well as at least one surface 842 and at least one surface 844 of the second region 840. In this way, centrifugal forces can be transmitted from the first region 830 to the second region 840, as described in connection with Figures 4 and 6. The projection 860 further improves the force transmission, since at least two surfaces 842 and 844 are provided at different locations within the second region 840 to absorb the centrifugal forces. This leads, firstly, to an improved distribution of the transmitted centrifugal forces across the second region and, secondly, to a reduction in the stress on the magnetic material, since the transmitted centrifugal forces are again distributed across two surfaces at different locations.This also increases the mechanical stability of the rotor lamination stack and reduces wear and tear on the magnetic material and the rotor lamination stack.

[0100] The surface of the first and / or second region of the rotor lamination stack 800 can be arranged on a projection 860 of the rotor lamination stack 800. A projection 860 can be a structural bulge or bump where contact with the magnetic material can be established. The projection 860 can also be designed such that it is only minimally tapered (i.e., narrower) compared to the adjacent gaps.

[0101] At least two surfaces of the projection 860 can be opposite each other or substantially parallel to each other, and the at least two surfaces of the at least one projection 860 of the first and / or the second surface of the magnetic material can also be opposite each other or substantially parallel to each other.

[0102] Providing a small protrusion or a small, directly adjacent arrangement of surfaces between the protrusion and the magnetic material can prevent or reduce the occurrence of magnetic short circuits between the permanent magnets.

[0103] Furthermore, the structural integration of the magnetic material into the rotor lamination stack 800 can also include the directly adjacent arrangement of the first and a third surface of the magnetic material and of two surfaces of the first region 830 of the rotor lamination stack 800 and / or the directly adjacent arrangement of the second and a fourth surface of the magnetic material and of two surfaces of the second region 840 of the rotor lamination stack 800.

[0104] The two surfaces of the first region 830 of the rotor lamination stack 800 can differ from each other. The first and third surfaces of the magnetic material can also differ from each other. Furthermore, the second and fourth surfaces of the magnetic material can differ from each other. Additionally, the two surfaces of the second region 840 of the rotor lamination stack 800 can differ from each other. The first and third surfaces of the magnetic material can also differ from each other. This allows for the optimization of the force distribution across different surfaces of different regions.

[0105] In some embodiments, the magnetic material can have a tapered section that divides the magnetic material into at least two segments, as illustrated, for example, in Figure 8. These segments can be separate magnetic segments with different magnets or structurally connected magnetic segments. Each segment can have its own structural integration into the rotor lamination stack, which allows centrifugal forces to be transmitted from the first region 830 of the rotor lamination stack 800 through the magnetic material of each segment to the second region 840 of the rotor lamination stack 800.

[0106] Furthermore, the additional design options described in connection with Figures 4 to 7 are also applicable to the embodiment of Figure 8.

[0107] Figure 9 shows another embodiment according to the present disclosure.[oio8] According to Figure 9, the rotor lamination stack 900 comprises a magnetic pocket 916, which divides the rotor lamination stack into a first region 930, which lies radially outside the magnetic pocket 916, and a second region 940, which lies radially inside the magnetic pocket 916. Magnetic material of any shape can be arranged in the magnetic pocket (not shown in Figure 9).

[0109] In the embodiment according to Figure 9, the rotor lamination stack comprises a first projection 960 and a second projection 970, each of which projects into the magnetic pocket 916 and is suitable for coming into contact with at least one surface of a magnetic material located in the magnetic pocket 916. Preferably, the first projection 960 is located on a side of the magnetic pocket 916 facing the second region 940, and the second projection 970 is located on a side of the magnetic pocket 916 facing the first region 930. Preferably, the first and second projections 960 and 970 are made of the same material as the rotor lamination stack 900; however, the projections can also be made of other materials, e.g., non-magnetic materials. Preferably, the two projections have similar dimensions, in particular, they have a similar width, ideally the same width.

[0110] Magnetic material can be inserted into the magnetic pocket 916. This material is preferably shaped such that it directly abuts at least one first surface 932 of the first region 930 and at least one second surface 934 of the first region 930, as well as at least one first surface 942 of the second region 940 and at least one second surface 944 of the second region 940. In this way, centrifugal forces can be transmitted from the first region 930 to the second region 940, as described in connection with Figures 4 and 6. The projections 960, 970 further improve the force transmission, since at least two surfaces 932 and 934 at different locations of the first region 930 and at least two surfaces 942 and 944 at different locations of the second region 940 are provided for centrifugal force transmission.This leads, firstly, to an improved distribution of the transmitted centrifugal forces on the second area and, secondly, to a reduction in the stress on the magnetic material, since here too the transmitted centrifugal forces are distributed over two surfaces at different locations. This also increases the mechanical stability of the rotor lamination stack and reduces wear of the magnetic material and the rotor lamination stack. [O111] The second projection 970 can be slightly offset from the first projection 960, preferably in the direction of the radially outer end of the magnet pocket 916. If two separate bar magnets or a segmented bar magnet are inserted into the magnet pocket, this can result in the radially inner bar magnet or segment being in contact with the surface 932 of the first area and with the surface 942 of the second area, but not with the projection 970.Furthermore, the radially outer bar magnet or bar magnet segment is then in contact with surface 934 of the first area and with surface 944 of the second area, but not with projection 960. This ensures the most efficient possible transfer of centrifugal forces from the first area 930 to the second area 940, because only the centrifugal forces of the respective section of magnetic material act on each subsection. Thus, the centrifugal force can be reduced by approximately half per section with two such sections. By using a larger number of projections 960, 970, correspondingly more sections or segments can be created, thereby enabling a further distribution of the centrifugal forces.Segmenting the bar magnets also reduces the mechanical stress on the magnetic material, as the already reduced force per section or segment is distributed over a larger total area.

[0112] Although the advantages of this embodiment have been described for better illustration in connection with the use of two separate bar magnets, the same technical advantages can be achieved when a single, continuous magnet is used. This magnet can, for example, have recesses corresponding to projections 960 and 670, while being continuous between projections 960 and 970.

[0113] Furthermore, the additional design options described in connection with Figures 4 to 8 are also applicable to the embodiment of Figure 9.

[0114] Figure 10 shows another design possibility according to the present revelation.

[0115] As shown in Figure 10, the rotor lamination stack 1000 comprises a magnetic pocket 1016 for receiving magnetic material 1012, 1014, which divides the rotor lamination stack 1000 into a first region 1030 and a second region 1040. Magnetic material can be arranged in the magnetic pocket 1016 in any desired form. For example, the magnetic material can be arranged as permanent magnets 1012 and 1014. Since the magnetic pocket 1016 is preferably continuous, there is a space 1022 in the magnetic pocket between the permanent magnets 1012 and 1014. As described in connection with other embodiments, this space 1022, which can be filled with non-magnetic material such as air, prevents the occurrence of magnetic short circuits between the permanent magnets 1012 and 1014.For example, additional gaps may also be present along the longer sides of the magnetic material, which are not shown in Figure 10. These gaps can be very narrow, which is why they are not clearly visible in Figure 10, and can ensure that the magnetic material 1012, 1014 does not touch the rotor lamination stack 1000 at any point except at the directly adjacent arrangements 1032, 1042. Thus, magnetic short circuits between the magnetic material 1012, 1014 and the rotor lamination stack 1000 can be avoided, since the contacting surfaces can be reduced to a minimum.

[0116] As shown in Figure 10, the magnetic pocket 1016 extends radially outwards and comprises two open ends at its radially outer ends. This results in the magnetic pocket 1016 having open ends 1018, 1020 at the location where, in other embodiments, gaps (for example, gaps 418 and 420 in Figure 4) were provided. This also results in the first region 1030 of the rotor lamination stack 1000 being mechanically decoupled from the second region 1040 of the rotor lamination stack 1000 at the radially outer region of the rotor lamination stack 1000. In this embodiment, the mechanical connection between the two regions is established solely via the magnetic material, which also creates a clamping connection between the two regions 1030, 1040. Furthermore, the otherwise mechanically stressed locations (locations 330 and 340 in Figure 3, respectively) are thus protected.Positions 530 and 540 in Figure 5 are no longer present, thus further preventing deformation and wear in these areas. This completely eliminates the mechanical weak point of the rotor lamination stack, enabling even higher performance of the electric drive and operation at even higher speeds without adversely reducing the air gap. The other advantages of the previously described design options are also retained. Furthermore, all other design options of this disclosure can be freely combined with the embodiment shown in Figure 10.

[0117] Furthermore, the geometry according to Figure 10 is suitable for transferring the centrifugal forces acting on the first region and the magnetic material to the second region in the same way as described in connection with Figure 4 or 6. For this purpose, according to Figure 10, the first directly adjacent arrangement 1032, which establishes contact between the first region 1030 and the radially inner end of the magnetic material 1012, 1014, and the second directly adjacent arrangement 1042, which establishes contact between the second region 1040 and the radially outer end of the magnetic material 1012, 1014, serve this purpose.Preferably, the two ends of the magnetic material are diagonally opposite each other, so that the structural integration of the magnetic material 1012, 1014 into the rotor lamination stack 1000 enables a mechanical force redirection from the first region 1030 of the rotor lamination stack 1000 through the at least one surface of the first region 1030 of the rotor lamination stack 1000, the at least one first surface of the magnetic material, the magnetic material, the at least one second surface of the magnetic material and the at least one surface of the second region 1040 of the rotor lamination stack 1000 to the second region 1040 of the rotor lamination stack 1000.

[0118] The design shown in Figure 10 also demonstrates that the magnetic material can be rounded instead of angular. This avoids high mechanical stresses, which are typically highest in corners. This further optimizes the stability of the rotor lamination stack. Furthermore, the surface area of ​​a single, directly adjacent arrangement, as shown in Figure 10 compared to Figure 9, can be increased. This results in a distribution of forces over larger areas, which also increases the mechanical stability of the rotor lamination stack 1000.

[0119] Figure 11 shows another embodiment according to the present disclosure.

[0120] As shown in Figure 11, the rotor lamination stack 1100 includes a magnetic pocket 1116 for receiving magnetic material 1112, 1114, which divides the rotor lamination stack 1100 into a first region 1130 and a second region 1140. The magnetic material 1112, 1114 can be arranged in any desired shape within the magnetic pocket 1116. For example, the magnetic material 1112, 1114 can be arranged as permanent magnets 1112 and 1114. Since the magnetic pocket 1116 is preferably continuous, there is a space 1122 within the magnetic pocket between the permanent magnets 1112 and 1114. As described in connection with other embodiments, this space 1122, which can be filled with non-magnetic material such as air, can prevent the occurrence of magnetic short circuits between the permanent magnets 1112 and 1114.

[0121] Furthermore, the magnetic pocket 1116 can include, in addition to the space 1122, further spaces 1118 and 1120, which are arranged at the radially outer ends of the permanent magnets 1112, 1114. The rotor lamination stack 1100 further comprises a structural integration of the magnetic material 1112, 1114, which has a first directly adjacent arrangement 1132 of at least one first surface of the magnetic material 1112, 1114 and at least one surface of the first region 1130. The structural integration of the magnetic material also has a second directly adjacent arrangement 1142 of at least one second surface of the magnetic material 1112, 1114 and at least one surface of the second region 1140 of the rotor lamination stack 1100.

[0122] Furthermore, the structural arrangement includes gaps in the areas of the magnetic pocket 1116 located outside the directly adjacent first and second arrangements 1132, 1142 and between the rotor lamination stack 1100 and the magnetic material 1112, 1114. Figure 11 shows, by way of example, a gap 1122 located in the radially inner region of the magnetic pocket 1116, as well as gaps 1118 and 1120 located in the radially outer region of the magnetic pocket 1116. As illustrated by way of example in Figure 11, the gaps 1118 and 1120 are located next to the second directly adjacent arrangement 1142, while gap 1122 is located next to the first directly adjacent arrangement 1132. For example, further gaps may also be located along the longer sides of the magnetic material, which are not shown in Figure 11.These gaps can be very narrow, which is why they are not clearly visible in Figure 11, and can ensure that the magnetic material 1112, 1114 does not touch the rotor lamination stack 1100 at any point except at the directly adjacent arrangements 1132, 1142. Thus, magnetic short circuits between the magnetic material 1112, 1114 and the rotor lamination stack 1100 can be avoided, since the contacting surfaces can be reduced to a minimum.

[0123] In the present embodiment, the first directly adjacent arrangement, located approximately between the magnetic material 1112, 1114 and the space 1122 near the center of the rotor pole, comprises a wedge-shaped area of ​​the first region 1130 of the rotor lamination stack 1100. Thus, the area into which magnetic material can be inserted laterally is pentagonal. Preferably, a correspondingly pentagonal magnet can be inserted into this area. However, in other embodiments, magnets of any other shape can be used, which lead to contact at the directly adjacent areas. For example, bar magnets could be used, which, for instance, have only one contact point with the wedge-shaped area of ​​the first directly adjacent region 1132.

[0124] This design has the advantage that the centrifugal force is deflected from the first area 1130 towards the second area 1140 simply by the inclination of the contact surface. This prevents the formation of a (right-angled) corner. This, in turn, prevents severe mechanical stress on the magnetic material, particularly from shear forces and shear stresses, as (right-angled) corners can represent the greatest mechanical weakness of the magnetic material. This prevents, for example, cracking in the magnetic material and increases the durability and reliability of the electric machine. The thickness and angle of the wedge-shaped intermediate piece can be adjusted according to the magnetic and mechanical requirements. For example, a rounded edge can be provided instead of a corner.

[0125] Furthermore, all other design possibilities of this disclosure can be freely combined with the embodiment shown in Figure 11.

[0126] Figure 12 shows another embodiment according to the present disclosure.

[0127] The structure of the rotor lamination stack 1200 according to Figure 12 essentially corresponds to the rotor lamination stack as shown in Figure 9 and described in that context. However, the rotor lamination stack 1200 of the present embodiment is additionally shaped such that, when no magnetic material is inserted therein, it includes a curvature 1236 in the first region 1230, which extends radially outwards. The curvature 1236 is shown schematically and is not necessarily to scale.

[0128] The function of the bulge 1236 is described below using an example. First, as indicated by dashed lines in Figure 12, a magnet, for example a bar magnet, is inserted into the magnetic pocket 1216. Preferably, this magnet has a greater longitudinal extent than the extent of an empty magnet pocket segment extending between the surface 1234 of the projection 1270 and the surface 1244 of the second region 1240 of the rotor lamination stack 1200. By pressing the magnet 1212 into this magnet pocket segment, the projection 1270, and thus the first region 1230 of the rotor lamination stack 1200, is pulled radially inwards, so that the rotor lamination stack, which had a bulge without the magnet, has a round shape with the magnet 1212 inserted. Thus, the additional material of the bulge 1236 ensures that the rotor lamination stack has sufficient deformability and clamping force to clamp the pressed-in magnetic material with sufficient force and, despite the mechanical deformation due to mechanical stress, to conform the rotor lamination stack to the desired round shape.The dimensioning of the curvature 1236 in Figure 12 is shown schematically for the purpose of description and may differ from the illustration.

[0129] Furthermore, the magnetic pockets 1216 can be widened by means of a force applied radially from the outside to the first area 1230 in order to introduce magnetic material 1212 with less force.

[0130] This arrangement ensures that the magnet is securely clamped in the magnet pocket segment, thus guaranteeing force transmission from the first area 1230 to the second area 1240 under all circumstances. Simultaneously, the rotor lamination stack 1200 is prestressed so that the mechanical stress vector counteracts the centrifugal force. The stress applied during the joining process is absorbed by the magnetic material 1212 and transferred to the second area 1240. The dashed line on the outer edge of the rotor lamination stack 1200 describes the circular circumference of the rotor lamination stack in its relaxed state at the end of assembly.

[0131] The angle between the legs of the magnetic material of a pole can vary. All the preceding figures illustrate simple and multiple V-arrangements of magnets. Neither the angle of the V-arrangement nor any other parameters should be considered fixed. Thus, the arrangement can be at least partially circular, for example U- or O-shaped, or alternately circular and straight. Furthermore, individual sections of the magnetic material can even be substantially parallel or at an angle of substantially 18° to each other. The invention relates primarily to the possibility of force redirection from the first region of the rotor lamination stack to the second region of the rotor lamination stack, and not to individual parameters or the shapes of the design depicted in the figures.

[0132] In all the embodiments described above, the centrifugal forces can be transmitted from the first region of the rotor lamination stack to the second region by means of the magnetic material. This is made possible in particular by the advantageous positioning of the magnetic material within the rotor lamination stack. Preferably, the magnetic material is fixed in pairs at diagonally opposite corners or points, while the other corners or points remain exposed, so that the magnetic material acts as a lever and redirects the centrifugal forces acting on the magnetic material and the first region to the second region, which, due to its potentially greater mass, size, or dimensions, may be better suited to absorbing these forces.These structural modifications increase the stability of the rotor lamination stack even at higher speeds and significantly improve the wear characteristics of an electric machine. While the preceding explanations assumed an internal rotor design, all embodiments are also applicable to an external rotor design. In this case, all described geometries would be inverted from the outside to the inside, but would then exhibit the same advantageous effects as in the described internal rotor design.

Claims

February 17, 2026 M0LAB0 GmbH M166314WO CKA / Wrd Claims 1 to 15 1. Rotor lamination package for a rotor of an electric machine, which comprises: -a magnetic pocket located within the rotor lamination stack; -a first area of ​​the rotor lamination stack, which is arranged radially outwards from the magnet pocket in the rotor lamination stack; -a second area of ​​the rotor lamination stack, which is arranged radially inwards from the magnet pocket within the rotor lamination stack; -magnetic material arranged in the magnetic pocket; and -a structural integration of the magnetic material into the rotor lamination stack, which features: -a first directly adjacent arrangement of at least one first surface of the magnetic material and at least one surface of the first region of the rotor lamination stack; -a second directly adjacent arrangement of at least one second surface of the magnetic material and at least one surface of the second region of the rotor lamination stack; and -Gaps formed in areas of the magnetic pocket located outside the directly adjacent first and second arrangements and between the rotor lamination stack and the magnetic material, wherein the rotor lamination stack is spatially separated from the magnetic material in the gaps; and wherein the structural integration of the magnetic material into the rotor lamination stack enables a mechanical force redirection from the first region of the rotor lamination stack through the at least one surface of the first region of the rotor lamination stack, the at least one first surface of the magnetic material, the magnetic material, the at least one second surface of the magnetic material, and the at least one surface of the second region of the rotor lamination stack to the second region of the rotor lamination stack.

2. Rotor lamination stack according to one of the preceding claims, wherein the at least one surface of the first and / or the second region of the rotor lamination stack is arranged on at least one projection of the rotor lamination stack.

3. Rotor lamination stack according to claim 2, wherein at least two surfaces of the at least one projection face each other or are essentially parallel to each other; and the at least two surfaces of the at least one projection of the first and / or the second surface of the magnetic material are opposite each other or are essentially parallel to each other.

4. Rotor lamination stack according to one of the preceding claims, wherein the at least one magnet pocket is a continuous recess in the rotor lamination stack.

5. Rotor lamination stack according to one of the preceding claims, wherein the at least one magnet pocket comprises one magnet or at least two separate magnets.

6. Rotor lamination stack according to one of the preceding claims, wherein the magnetic material comprises one or more bar magnets and wherein the one or more bar magnets have a straight, bent or kinked shape.

7. Rotor lamination stack according to one of the preceding claims, wherein the structural integration of the magnetic material into the rotor lamination stack comprises a positive-locking, force-locking or material-locking connection between at least two or more of the following locations in the rotor lamination stack: the at least one first surface of the magnetic material, the at least one second surface of the magnetic material, the surface of the first region of the rotor lamination stack and the surface of the second region of the rotor lamination stack.

8. Rotor lamination stack according to one of the preceding claims, wherein the structural integration of the magnetic material into the rotor lamination stack comprises: - a directly adjacent arrangement of the first and a third surface of the magnetic material and of two surfaces of the first region of the rotor lamination stack; -a directly adjacent arrangement of the second and a fourth surface of the magnetic material and of two surfaces of the second area of ​​the rotor lamination stack.

9. Rotor lamination stack according to claim 8, wherein -distinguish the two surfaces of the first area of ​​the rotor lamination stack from each other; and / or -distinguish the first and third surfaces of the magnetic material from each other; and / or -distinguish the second and fourth surfaces of the magnetic material from each other; and / or -distinguish the two surfaces of the second area of ​​the rotor lamination stack from each other; and / or -distinguish the first and third surfaces of the magnetic material from the second and fourth surfaces of the magnetic material.

10. Rotor lamination stack according to one of the preceding claims, wherein the first surface of the magnetic material is opposite the second surface of the magnetic material on an intervening rod-shaped section of the magnetic material, or is substantially parallel to each other; and wherein the rod-shaped section of the magnetic material has a straight, curved or bent shape.

11. Rotor lamination stack according to one of the preceding claims, wherein the at least one magnetic pocket is a one-piece and continuous opening in the rotor lamination stack containing only materials that differ from the material of the rotor lamination stack.

12. Rotor lamination stack according to one of the preceding claims, wherein the first region of the rotor lamination stack is located in the middle of a rotor pole of the rotor lamination stack formed by the magnetic material and wherein the second region of the rotor lamination stack is located between two rotor poles of the rotor lamination stack.

13. Rotor lamination stack according to one of the preceding claims, wherein the spaces between are at least partially filled with a non-magnetic material, preferably with a paramagnetic or diamagnetic material, more preferably with air and / or non-magnetic bonding materials such as adhesives or resins.

14. Rotor lamination stack according to one of the preceding claims, wherein -the magnetic material has a tapered section that divides the magnetic material into at least two segments; -where at least two segments are separate magnetic segments of different magnets or structurally interconnected magnetic segments of a single magnet; and -each segment has its own structural integration into the rotor lamination stack, which enables the transfer of centrifugal forces from the first area of ​​the rotor lamination stack through the magnetic material of each segment to the second area of ​​the rotor lamination stack.

15. Rotor lamination stack according to one of the preceding claims, wherein -the rotor lamination stack, excluding the magnetic material, has at least one section which, viewed from an axis of rotation of the electric machine, has a radius larger than the corresponding radius of the rotor lamination stack; and -the rotor lamination stack with the magnetic material in the magnet pocket has a continuous radius equal to that of the rotor lamination stack.

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