Segmentation arrangement for permanent magnets of a double-V arrangement in a rotor for a permanent magnet electric machine

Description

[0001] The invention relates to a segmentation arrangement of an inner and an outer magnet of at least one leg of at least a double-V arrangement of permanent magnets in a rotor for a permanent magnet electric machine. The invention also relates to a rotor comprising at least one such double-V arrangement with at least four permanent magnets, and to a permanent magnet electric machine comprising at least one rotor.

[0002] Electrical machines can be, for example, electric motors and / or generators, with electric motors being particularly common in the automotive sector. The use of an electric motor to propel a vehicle is especially preferred. A preferred embodiment is a rotary electric machine in which a rotor rotates within a stator, which is, for example, rigidly connected to a vehicle. A permanent magnet electric machine can be characterized by the presence of permanent magnets in the rotor and coils in the stator, which generate a rotating magnetic field via an electric current.

[0003] This rotating magnetic field of the coils is not constant, but changes over time as the current flow through the coils is regulated accordingly. This results in time-varying magnetic fields that interact with the magnetic fields of the permanent magnets in the rotor, causing the rotor to rotate uniformly when the change in current flow is coordinated with the rotor's rotation.

[0004] This temporal change in the magnetic field, caused by the temporal change in the current flow through the coils, has at least one further effect. According to Maxwell's equations, a time-varying magnetic field can, for example, lead to an electric vortex field. This electric vortex field can form particularly in the rotor of the permanent magnet electric machine, since it is directly related to the changing magnetic field, which also penetrates the rotor.

[0005] The rotor of a permanent magnet electric machine can, however, be made of an electrically conductive material, whereby the electric eddy currents induce a current flow in the rotor. This leads to unwanted heating of the rotor and efficiency losses. A laminated construction can counteract this.

[0006] Additionally or alternatively, the permanent magnets in the rotor can also be made of an electrically conductive material. Sintered Nd-Fe-B magnets, in particular, possess high conductivity. Since the changing magnetic fields of the coils can also penetrate the rotor's permanent magnets, eddy currents can be generated within them, leading to undesirable heating and efficiency losses.

[0007] One way to counteract this is to segment the permanent magnets. Examples of segmentation can be found in German patent applications DE 10 2021 006 006 A1, DE 10 2021 002 942 A1, EP3 457 532 A1, EP 3 457 535, EP 2 264 860, US 2016 / 005525, and FR 3 134 669. Segmentation of a permanent magnet, for example, can be characterized by cuts, incisions, and / or cutouts, which can increase the surface area. More specifically, this results in the entire permanent magnet being divided into several smaller areas. These areas may or may not be contiguous, with current flow between them either prevented or permitted only via the connections (e.g., in the form of material bridges).Another possibility for segmentation therefore consists of constructing a permanent magnet from several permanent magnets, which are connected to each other via electrically non-conductive layers.

[0008] Thus, a permanent magnet can be segmented in several ways. Examples include a stack of individual permanent magnets, preferably connected by electrically non-conductive layers, and / or cuts in the permanent magnet that extend through the entire magnet, as shown, for example, for meandering cuts in Fig. 8 of German patent DE 10 2021 002 942 A1, and / or incisions that only cut through a portion of the permanent magnet, as shown, for example, in Fig. 6 of German patent DE 10 2021 002 942 A1, where the remaining material bridge is designated by the reference numeral W. The cuts and / or incisions can have different shapes, for example, comb-like, meandering, and / or through-and-through. Additionally or alternatively, cutouts are also possible.

[0009] A cut or the cutting plane runs through the entire permanent magnet in one direction, that is, preferably in the direction perpendicular to the surface in which the cut is to be made (this is preferably the surface of the permanent magnet with the largest area). A notch or groove, on the other hand, is analogous to a cut, except that the notch does not run through the entire magnet in one direction, so that a material bridge remains, particularly in this direction, through which areas separated by a cut remain at least partially connected. A cutout, however, consists of several cuts that are joined to form a closed shape, so that the contents of the shape are no longer connected to the rest of the permanent magnet due to the cuts.The cutouts can therefore be holes, especially through holes of any shape.

[0010] A segmentation can preferably be characterized by a direction. This direction of segmentation is determined by the segmentation boundaries. The segmentation boundaries are those cuts, incisions, cutouts, or layers that serve as delineations between the individual regions of the permanent magnet. In particular, the segmentation boundaries can run parallel to each other, especially plane-parallel. The preferred direction of these segmentation boundaries, that is, the direction in which the segmentation boundaries most frequently run on average when considering the entire permanent magnet, is considered the direction of segmentation determined by the segmentation boundaries. This direction is also referred to as the segmentation direction.In particular, the segmentation direction for parallel segmentation boundaries is to be considered as a direction parallel to the segmentation boundaries. Preferably, only the side of the permanent magnet with the largest surface area is considered to determine the segmentation direction. Furthermore, it should be noted that the depth direction of the segmentation, that is, the direction from the surface into the permanent magnet, is preferably perpendicular to the surface with the largest area.

[0011] A preferred arrangement of the permanent magnets in the rotor is the double-V arrangement. This is discussed, for example, in German patent applications DE 10 2021 002 938 A1, DE 10 2021 002 130 A1, DE 10 2019 132 188 A1, and EP 3 352 337 A1. The rotor can thus be defined by an axis of rotation, or rotor axis, around which it rotates. The direction along this axis is referred to as the axial direction with respect to the axis of rotation, or simply the axial direction. The direction that is perpendicular to the axial direction and thus points radially outward is called the radial direction. A third direction, the circumferential direction, should also be defined. This is perpendicular to both the axial and radial directions and thus points in the direction of a tangent to a circle with the axis of rotation as its center.

[0012] As can be seen, for example, from the aforementioned publications, the permanent magnets in a rotor can be arranged in a double-V configuration, as is also the case, for example, with Fig. 1 This is evident from the publication DE 10 2021 002 938 A1. The double-V arrangement is characterized, among other things, by the fact that the permanent magnets in the rotor are arranged along two radially aligned "V" shapes, one after the other, or one above the other, with each pair of permanent magnets forming the legs of a "V". The leg of a "V" describes one side of the letter V, which is separated from the other side by an axis of symmetry. The term "leg" of a double-V arrangement refers to two radially aligned legs of two V shapes in a double-V arrangement.

[0013] This structure, as described above, will be further illustrated below using the following example: Fig. 1 This will be illustrated. For example, it shows Fig. 1 A section of a rotor 10, in particular of a permanent magnet electric machine, which can rotate about an axis of rotation 11. The directions are also defined on the basis of this axis of rotation 11, whereby the direction along the axis of rotation 11 is to be called the axial direction 12 and the direction perpendicular to the axis of rotation 11 and thus pointing outwards from the axis of rotation is to be called the radial direction 13.

[0014] Within this rotor 10 are at least four permanent magnets 14, which can be arranged in the rotor 10 according to a double-V arrangement 15. For this purpose, two permanent magnets 14 are arranged according to a "V", thus forming the legs of the V, with each pair of Vs arranged one above the other in the radial direction 13. The permanent magnets 14 located inner in the radial direction 13 are referred to as inner magnets 16, while the permanent magnets 14 located further out in the radial direction 13 are referred to as outer magnets 17.

[0015] This design gives the double-V arrangement a symmetry axis 18, which runs radially 13 between the permanent magnets 14. This divides the double-V arrangement into the two segmentation arrangements 19, each consisting of one leg of each V.

[0016] The permanent magnets 14 can exhibit segmentation, with A, B, and C showing examples of segmentation of a permanent magnet 14. The lines shown in A and B represent cuts and / or incisions and / or cutouts 20 of the permanent magnet 14, by which it is divided into different regions. C, on the other hand, shows a permanent magnet 14 composed of several permanent magnets that form the individual regions and are connected to each other via electrically non-conductive layers 21 made of electrically non-conductive material, while A shows an example of cuts for segmentation and B shows an example of a meandering incision. These cuts and / or incisions and / or cutouts 20 and / or the electrically non-conductive layers 21 represent the segmentation boundaries.In A, B and C, an arrow in each case indicates the direction 22 of the segmentation given by the segmentation boundaries or the segmentation direction 22.

[0017] The generic document EP 2 264 860 A1 also shows a rotor with a so-called double-V arrangement, in this case for a rail-mounted electric vehicle. The rotor body has a laminated sheet metal arrangement with a multitude of longitudinal slots for embedding magnets. For this purpose, the magnets are formed in the form of packs of two or more permanent magnets arranged side by side in a layer in the transverse and / or longitudinal direction of the slot. Layers of electrically insulating material separate the permanent magnets of each pack from each other and also separate the outer surfaces of the permanent magnet pack from sections of the rotor body plates that define the respective slot.

[0018] Also known from DE 10 2019 205 999 A1 is a rotor of an electric machine in which magnetic pockets extend in a double-V arrangement within the laminated core. Each magnetic pocket contains a magnetic body with at least two permanent magnets extending along the rotor axis, the magnetic body comprising a plastic filler material in which the permanent magnets are embedded.

[0019] German patent DE 10 2013 211 858 A1 describes a magnet for a rotor or stator of an electric machine, comprising a base and a raised portion that is superior to the base. This raised portion can also consist of a second twisted permanent magnet element with the same base area as a first permanent magnet element. The rotor or stator is made of a laminated core and features an undercut to accommodate and hold the raised portion of the magnet.

[0020] WO 2023 / 041260 A1 specifies a magnetic body made of a permanent magnetic material, wherein the magnetic body has a number of parallel, slot-shaped first recesses extending from a first side to a center of the magnetic body and the magnetic body has a number of parallel, slot-shaped second recesses extending from an opposite second side to the center of the magnetic body.

[0021] In addition, EP 1 746 611 A1 discloses a rare-earth permanent magnet made of a sintered magnetic body with a special composition, wherein a plurality of slots are formed in a surface of the magnetic body.

[0022] The invention aims to improve loss savings in the context of a permanent magnet electric machine.

[0023] The problem is solved by the subject matter of the independent patent claims. Advantageous further developments of the invention are described by the dependent patent claims, the following description, and the figures.

[0024] As a solution, the invention comprises a segmentation arrangement of the permanent magnets, in particular of a permanent magnet electric machine, which is especially preferably configured as a drive system, particularly for a motor vehicle. The invention relates to a segmentation arrangement of an inner and an outer magnet of a leg of a double-V arrangement of magnets in a rotor for a permanent magnet electric machine, wherein, in the leg described, the inner magnet is arranged further inwards in the radial direction with respect to the axis of rotation than the outer magnet. As is already known from the prior art, a segmentation can preferably be characterized by a single direction. According to the invention, a segmentation of the respective magnet is characterized essentially by a single direction, wherein the direction is determined by the segmentation boundaries.

[0025] Therefore, only one leg of a double-V arrangement will be considered here, focusing on the orientation of the segmentation direction of the inner magnet relative to the segmentation of the outer magnet. The segmentation arrangement is designed such that the segmentation boundaries of the outer magnet exhibit an angle β of 80° to 100° relative to the segmentation boundaries of the inner magnet.

[0026] This means that when considering the segmentation directions of the inner and outer magnets of the leg of the double-V arrangement or the segmentation arrangement, these segmentation directions are essentially orthogonal to each other, so the angle β - considered in magnitude - between the two directions can range from 80° to 100°.

[0027] It has been observed that losses due to eddy currents are suppressed particularly effectively when the angle between the segmentation directions of the inner and outer magnets exhibits a specific angular offset. By selecting an angle β ranging from 80° to 100°, precisely this observed effect can be exploited. This results in the advantage of particularly effective suppression of eddy currents in at least one permanent magnet—preferably in both permanent magnets of the leg of the double-V arrangement.

[0028] The invention also includes further developments that result in additional advantages.

[0029] A further development provides that the inner magnet has an overlapping region and a directly adjacent non-overlapping region. The overlapping region describes a radial angular area of ​​the leg, starting at an axis of symmetry of the double-V arrangement, in which both the inner and outer magnets are located, while only the inner magnet is located in the non-overlapping region. This means that the inner magnet is divided into exactly two regions. Here, an angle φ is considered, which extends from the axis of symmetry of the double-V arrangement in the direction in which the leg under consideration is located. This means that when considering the leg of the double-V arrangement that is to the right of the axis of symmetry when viewed from a top view of a cross-section of the rotor from the axial direction, the angle φ is measured clockwise.Right of the axis of symmetry means that when viewing the rotor from above and considering the radial direction from the inside out, the leg is to the right of the axis of symmetry. Similarly, left of the axis of symmetry is defined as follows: when viewing the leg to the left of the axis of symmetry, the angle φ is measured counterclockwise.

[0030] If, starting from the axis of symmetry, a range of angles is considered in an angular direction corresponding to the measurement direction of angle φ, the first range, i.e., the range with a smaller angle φ, is one in which both the inner and outer magnets are located. This range is called the overlap range. Immediately following this is the non-overlap range, which is characterized by the fact that the angle φ has larger values ​​than the angle φ in the overlap range, and only the inner magnet is located in this range.

[0031] In summary, the boundaries of the overlap region are defined by the angles φ that determine the outer ends of the outer magnet in the φ direction. The non-overlap region adjoins the overlap region and therefore extends from the boundary of the overlap region corresponding to the larger value of φ to the outer end of the inner magnet. The outer end of the inner magnet is defined as the point where the angle φ is maximized, provided that a line in the radial direction, which forms an angle φ with the axis of symmetry, at least touches the inner magnet. A corresponding definition applies to the outer end of the outer magnet.

[0032] The further development now provides that the inner magnet only exhibits segmentation in the non-overlapping region, which simultaneously means that the inner magnet has no segmentation in the overlapping region and can therefore be considered a single region with respect to segmentation in the overlapping region. For this purpose, it may be possible to use a non-stacked arrangement of individual magnets, preferably connected via electrically non-conductive layers, for the segmentation of the inner magnet.Preferably, however, a method is chosen for the segmentation of the inner magnet in which segmentation is carried out by cuts and / or incisions and / or cutouts, wherein these cuts and / or incisions and / or cutouts can be made through the entire magnet perpendicular to the direction in which the angle φ is measured and / or can only be made partially through the inner magnet, so that a material bridge remains in the thickness of the inner magnet.

[0033] The advantage here is that electrical eddy currents in the inner and outer magnets can be suppressed, while simultaneously reducing segmentation costs through the incomplete segmentation of the inner magnet. Incomplete segmentation means that the inner magnet is segmented only in the non-overlap region, while it remains segmented in the overlap region. Furthermore, this approach reduces the torque loss that can result from segmentation.

[0034] A further development of this approach proposes that the segmentation of the inner magnet extends to an outer end of the inner magnet, where the outer end is the end of the inner magnet at which the angle φ between the axis of symmetry of the double-V arrangement and the outer end of the inner magnet is at its maximum. Here, the angle φ is considered both in magnitude and in the corresponding measurement direction. For a V-shaped arrangement, the outer end of one leg would therefore be the upper tip of the corresponding leg of the V. The segmentation of the inner magnet thus extends from the outer end to the boundary of the non-overlap region, which is characterized by a value for the angle φ and does not describe the interface between the overlap and non-overlap regions.

[0035] Segmentation by external cuts and / or incisions is particularly easy to achieve and therefore especially advantageous. External cuts and / or incisions are defined as those made from the outer end of the inner magnet, preferably in the opposite direction to the angle φ measurement. Thus, a meandering shape is preferably not chosen for the cuts and / or incisions and / or cutouts. This results in the advantage of easily implemented segmentation, which effectively suppresses eddy currents in the at least one permanent magnet while reducing torque loss due to segmentation.

[0036] An alternative development involves completely segmenting the inner magnet. This means that at least 90% of the surface of the inner magnet with the largest area is divided into several regions by segmentation. Preferably, the entire surface of the inner magnet with the largest area is segmented. In this case, a segmentation of the inner magnet is preferably chosen in which the inner magnet is composed as a stack of several permanent magnets connected to each other by electrically non-conductive layers.Alternatively, a segmentation method is preferred in which sections are made perpendicular to the surface of the inner magnet, starting from at least one surface with the largest area, and passing through the inner magnet, with at least 90% of the surface with the largest area being segmented in this way. This offers the advantage that segmentation methods can be used which are not available, or only available to a limited extent, in the context of only partial segmentation of the inner magnet.

[0037] A further development involves setting the angle α between the segmentation boundaries of the inner magnet and the circumferential direction to 0°. Here, the radial direction is perpendicular to the axial direction with respect to the axis of rotation and points away from the axis of rotation, while the circumferential direction is perpendicular to both the radial and axial directions with respect to the axis of rotation. This means that the angle α describes the angle between the segmentation direction of the inner magnet and the circumferential direction and is 0°, or that the segmentation direction and the circumferential direction point in the same direction. Preferably, a method is used for segmentation in which the inner magnet consists of a stack of several permanent magnets connected by layers of electrically non-conductive material, or the segmentation is characterized solely by cuts and / or incisions in the circumferential direction.Preferably, all angles characterizing the segmentation are therefore multiples of 90°. That is, the cuts and / or incisions, or the electrically non-conductive layers separating the permanent magnets, are perpendicular to the surfaces of the inner magnet that they cut through.

[0038] The basic shape of the permanent magnets is preferably a cuboid, preferably spanned by three sides or edges or vectors of different lengths. In particular, the opposite surfaces spanned by the two longest of the three differently sized sides are thus the surfaces with the largest area, and therefore the surfaces for segmentation.

[0039] This offers the advantage that segmentation through right angles can be easily carried out, and an angle α of 0° can be easily and therefore cost-effectively achieved in the manufacturing process.

[0040] Further development involves assuming complete segmentation of the inner magnet and an angle α of 0° for segmentation, a stacking of individual magnets and / or cuts and / or incisions and / or cutouts are present on at least 90% of the total surface of the inner magnet, and thus the areas resulting from the segmentation have a cuboid shape. It can be assumed that the inner magnet itself has a cuboid shape. This means, in particular, that the angles between the segmentation boundaries and the surfaces of the inner magnet are always multiples of 90°, as can already be the case when α = 0°. Thus, the segmentation results in areas that have a cuboid shape; these areas form parallelepipeds in which every angle is 90°.

[0041] In particular, segmentation can preferably be achieved by stacking several permanent magnets connected to each other via electrically non-conductive layers. Additionally or alternatively, segmentation characterized by cuts extending over at least 90% of the surface of the inner magnet with the largest area is preferred.

[0042] The advantage here is the easily achievable segmentation, which allows for effective and cost-efficient production.

[0043] A further development proposes that, as an extension of the previously considered characteristics, the angle α of the inner magnet has a value ranging from 0° to 45°. Here, the angle α is, as already described, the angle that the segmentation direction forms with the circumferential direction. This means that the segmentation direction of the inner magnet essentially points in the circumferential direction, thus ensuring particularly effective suppression of eddy currents within the inner magnet.

[0044] A further development proposes that the outer magnet has a segmentation whose segmentation boundaries form an angle α2 of 0° to 45° with respect to the axial direction and the axis of rotation. This means that the segmentation direction forms an angle α2 with the axial direction, which can have a value of 0° to 45°. The segmentation direction of the outer magnet is therefore essentially parallel to the axial direction. This results in a particularly effective suppression of eddy currents in the outer magnet.

[0045] So far, only one leg of the two legs of a double-V arrangement has been considered, which corresponds to the segmentation arrangement. The characteristics of the segmentation arrangement can therefore be applied to both legs of the double-V arrangement.

[0046] Thus, the invention further comprises a double-V arrangement comprising two segmentation arrangements, each segmentation arrangement comprising the features of an embodiment of one of the previously described segmentation arrangements and forming one leg of the double-V arrangement, wherein the segmentation arrangements are arranged such that they are symmetrical about the axis of symmetry of the legs of the double-V arrangement. This means that two segmentation arrangements each form a double-V arrangement. For this purpose, the segmentation arrangements are positioned such that the axis of symmetry, about which the segmentation arrangements are arranged symmetrically, runs radially between these two segmentation arrangements. This also means that the two segmentation arrangements preferably have the same features.Furthermore, the segmentation arrangements can be arranged such that the end of the permanent magnets of one segmentation arrangement which is furthest inwards, i.e., which has the smallest radial distance to the axis of rotation, points towards the axis of symmetry and thus towards the other segmentation arrangement.

[0047] The invention also includes, as further solutions, a rotor for a permanent magnet electric machine with at least one double-V arrangement, and a permanent magnet electric machine with a corresponding rotor. Preferably, this permanent magnet electric machine is one used for a motor vehicle, in particular for the propulsion of an electrically powered motor vehicle, which may have other forms of propulsion in addition to an electric drive.

[0048] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings. The features and combinations of features mentioned above in the description, as well as those mentioned below in the figure description and / or shown in the figures alone, can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention.

[0049] The following are exemplary embodiments of the invention described. This is illustrated by: Fig. 1 shows a schematic representation of part of a rotor of a permanent magnet electric machine, as is already known from the prior art; Fig. 2 shows a schematic representation of an embodiment of a segmentation arrangement according to the invention; Fig. 3 shows another representation of an embodiment of a double-V arrangement comprising two segmentation arrangements according to the invention; Fig. 4 shows a schematic representation of part of a permanent magnet electric machine; and Fig. 5 shows various embodiments of a segmentation arrangement according to the invention.

[0050] The exemplary embodiments described below are preferred embodiments of the invention. In these exemplary embodiments, the described components each represent individual features of the invention, which can be considered independently of one another and each further develops the invention independently. Therefore, the disclosure is intended to include combinations of features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

[0051] In the figures, identical reference symbols denote functionally equivalent elements.

[0052] Fig. 2 Figure 1 shows an embodiment of the segmentation arrangement 19, in which the rotation axis 11 of a rotor in which the segmentation arrangement 19 is located is also shown, as well as the axis of symmetry 18 of the double-V arrangement 15, of which the segmentation arrangement 19 shown is a part.

[0053] The segmentation arrangement 19 can comprise two permanent magnets 14, wherein the permanent magnet located closer to the axis of rotation 11 in the radial direction 13 is referred to as the inner magnet 16, and the permanent magnet located further away from the axis of rotation 11 in the radial direction is referred to as the outer magnet 17. Both permanent magnets 14 can have segmentation boundaries 23 due to segmentation, with examples of segmentation in Fig. 1 are given by reference numerals 20 and 21.

[0054] The segmentation boundaries 23 of the outer magnet 17 can preferably run in the axial direction 12, as shown in Fig. 2 The segmentation direction 22 of the outer magnet can, however, generally have an angle α2 with the axial direction 12, which can range in magnitude from 0° to 45°. Additionally or alternatively, the segmentation boundaries 23 of the inner magnet 16 can run along the direction of rotation U, as shown in Fig. 2 The segmentation direction 22 of the inner magnet 16 can, however, have an angle α with the direction of rotation, which can range from 0° to 45°. A particularly preferred configuration of the segmentation directions 22 is one in which the angle β between the segmentation direction 22 of the inner magnet 16 and the segmentation direction 22 of the outer magnet 17 can range from 80° to 100°, but preferably assumes the value 90°, as in the exemplary embodiment shown in Fig. 2 is shown.

[0055] While the segmentation of the outer magnet 17 is preferably a complete segmentation, in which at least 90% of the surface with the largest area is characterized by segmentation boundaries 23, the segmentation of the inner magnet 16 can also be a complete segmentation. Preferably, however, the segmentation of the inner magnet 16 is an incomplete segmentation, such that the inner magnet 16 only has a segmentation of the non-covering region 24, while the covering region 25 has no segmentation.

[0056] Here, the overlap region 25 forms the angular region in which both the inner magnet 16 and the outer magnet 17 are located, with the outer magnet 17 being completely within the overlap region 25. The overlap region 25 is described by an angle φ which extends circumferentially from the axis of symmetry 18 in the direction in which the permanent magnets 14, and thus the segmentation arrangement 19, are located. In the present embodiment, which in Fig. 2 As shown, the segmentation arrangement 19 is located to the right of the axis of symmetry 18, whereby the angle φ is measured clockwise from the axis of symmetry 18.

[0057] The overlap region 25 is therefore the angular region defined by the angle φ, i.e., the region bounded on one side by the axis of symmetry 18 and on the other side by a straight line in the radial direction 13, which forms an angle φ with the axis of symmetry. The angle φ is chosen such that the straight line in the radial direction, which delimits the overlap region 25, touches the outer end 26 of the outer magnet 17. The outer end 26 of the outer magnet 17 is defined by the point and / or edge of the outer magnet 17 whose angular distance φ (measured in absolute terms) between the axis of symmetry 18 and the straight line in the radial direction that touches the point and / or edge is maximal. Preferably, the overlap region 25 is only that region of the inner magnet 16 which lies within the overlap region 25 defined by the angle φ.

[0058] The non-overlap region 24, on the other hand, is the region which directly adjoins the overlap region 25, in particular of the inner magnet 16, and has larger values ​​for φ than points in the overlap region 25. The non-overlap region 24 can extend from the overlap region 25 of the inner magnet 16 to the outer end of the inner magnet 16, where the outer end of the inner magnet can be defined analogously to the outer end 26 of the outer magnet 17.

[0059] Fig. 3 schematically shows a double-V arrangement comprising two segmentation arrangements from a different perspective than shown in Fig. 1 and Fig. 2 are shown. This shows Fig. 3 Two outer magnets 17 and two inner magnets 16, each of which has a segmentation and thus segmentation boundaries 23. These segmentation boundaries 23 can have an orientation such that they are, for example, in Fig. 3 shown, perpendicular to each other, wherein the segmentation boundaries 23 of the outer magnets 17 can be aligned along the axial direction and the segmentation boundaries 23 of the inner magnets can be aligned along the circumferential direction U.

[0060] Fig. 4 Figure 1 shows a schematic representation of a permanent magnet electric machine comprising a rotor 10 and a stator 28, the stator containing coils 27. Permanent magnets 14 are arranged in the rotor according to at least a double-V arrangement 15, the permanent magnets being grouped into inner magnets 16 and outer magnets 17, and the inner magnets 16 each having an overlapping region 25 and a non-overlapping region 24. Their common boundary is defined by the angle φ.

[0061] Fig. 5 In contrast, Figure 1 shows various embodiments of the segmentation arrangement, wherein the outer magnets 17 are shown in the upper row, while the inner magnets 16 are shown in the middle and lower rows, which can each form an embodiment of the segmentation arrangement with the outer magnet 17 lying in the upper row of the same column, in which the angle β between the segmentation directions is 90°.

[0062] Here, the inner magnet 16 can be divided into an overlap area 25 and a non-overlap area 24, whereby in the example of the inner magnet 16 in the bottom row there is only a segmentation of the non-overlap area 25.

[0063] The horizontal arrows illustrate the circumferential direction U as the orientation for defining the angle α, the vertical arrows the axial direction for defining the angle α2.

[0064] A particularly preferred embodiment is given below: A double-V arrangement of the permanent magnets is particularly preferred for rotors, especially for permanent magnet electric machines. These are generally segmented to reduce eddy current losses at the permanent magnets. The segmentation is implemented in all magnets either in the rotational or axial direction. As a result, the potential loss savings cannot be fully exploited.

[0065] One solution is to implement the different magnet positions in a segmentation arrangement with different segmentation directions for the permanent magnets. Thus, the inner and outer magnets have different segmentation directions. Losses are minimized if the segmentation direction of the inner magnet has a specific angular offset from the segmentation direction of the outer magnet.

[0066] The solution can consist of an angular offset between the segmentation directions of the outer and inner magnets. Essentially, this involves the orientation of the segmentation of the inner magnet, which is preferably orthogonal to the segmentation direction of the outer magnet, but can generally have an angle of 80° to 100°. Both the inner and outer magnets can be segmented in different ways, either completely or partially.

[0067] Additionally, this angular offset offers the possibility of not fully segmenting the inner magnet. Partial segmentation may suffice, whereby segmentation only occurs in the non-overlapping area.

[0068] Reducing eddy current losses at the permanent magnets in rotating permanent magnet electric machines, particularly through segmentation, can result in increased efficiency and / or a reduction in magnet temperature, which in turn can lead to a reduction in the use of rare earth elements in manufacturing. Therefore, segmentation can reduce the manufacturing costs of permanent magnets by decreasing the amount of rare earth elements required, as the lower temperature of the permanent magnets results from the reduction in eddy currents.

[0069] Incomplete segmentation of the lower inner magnet can reduce segmentation costs and decrease the torque loss caused by segmentation.

[0070] Further preferred embodiments are described below: For example, permanent magnets in a double-V arrangement in the rotor of an electric machine can be specifically segmented to reduce eddy currents in the magnets and thus increase efficiency and performance. This involves segmenting the magnets to reduce eddy currents. In particular, the combination and orientation of the two segmentation directions between the two magnets (layers) in the double-V arrangement can be considered. This is symmetrical for both legs of the V. Thus, only one segmentation arrangement (one leg of the double-V arrangement) can be considered initially, with a subsequent extension to both legs possible.

[0071] The segmentation arrangement can, in particular, include a (complete) circumferential segmentation of the radially outer magnet, such that the sections or segment boundaries run axially. In contrast, the segmentation of the radially inner magnet can be limited to the area not covered by the outer magnet (non-coverage area) and be (essentially) axially oriented there, so that the sections and segment boundaries can run circumferentially and thus be essentially orthogonal to the segmentation of the outer magnet. Alternatively, the inner magnet can be completely segmented.

[0072] Segmentation can be achieved in a variety of ways; there are various possibilities or methods for carrying out segmentation. In particular, the external magnet can be freely designed to suit the type of segmentation.

[0073] The inner magnet can be segmented, with the segmentation being essentially orthogonal to the segmentation of the outer magnet, particularly in the area not covered by the outer magnet (non-overlap area). (The inner and outer magnets in the double-V cannot be of the same length; in particular, the radially inner magnet can be longer and thus only covered by the outer magnet in the inner radial angular region of the V (overlap area), and not covered by the outer magnet in the outer region (non-overlap area). The segmentation of the outer magnet can be essentially circumferential (cuts / segment boundaries run essentially axially). Additionally or alternatively, the radially inner magnet can be segmented essentially orthogonally to the segmentation of the outer magnet in the axial direction (cuts / segment boundaries in the circumferential direction).

[0074] Essentially in the circumferential direction, this means that the outer magnet forms an acute angle (45°>α2>0°) between the cuts and the axial direction (arrow pointing upwards). Fig. 5 ) may be observed. This can mean that an acute angle (45°>α>0°) exists between the sections and the circumferential direction (arrow pointing right in ). Fig. 5 ) can occur at the inner magnet. In particular, the two orientations can be essentially orthogonal and thus have an angle to each other of 80°<β<100°.

[0075] Segmentation can be achieved in at least one of several ways, such as stacking (individual) magnets, making cuts in the magnets that go all the way through (cuts), or cutting through only a portion of the magnet (incisions). Additionally or alternatively, the segmentation pattern can have at least one of the following shapes, for example, comb-like, meandering, and / or continuous.

[0076] When segmenting the inner magnet, the feature that only the uncovered area is segmented can be limited to preventing stacks of magnets. Instead, cuts and / or incisions can be made in the magnet from the outside. These can be continuous (cuts; completely severing the magnet) or partial (incisions; a material bridge remains in the thickness). A meandering shape can also be excluded, meaning the cuts and / or incisions can always extend to the outermost edge of the magnet.

[0077] Alternatively, the inner magnet can be segmented across its entire surface (including the covered area; segmentation in the covered and uncovered areas). This can result in a stack of magnets as the segmentation. Additionally or alternatively, longitudinal sections are also possible. The segmentation of the outer magnet, however, can be chosen arbitrarily. The orientation of the outer magnet's segmentation can be essentially orthogonal to the orientation of the inner magnet's segmentation.

[0078] In particular, the segmentation can be achieved via a stack of magnets or by cuts and / or incisions over at least 90% of the magnet's surface. This can be the case, in particular, if the inner magnet is completely segmented (i.e., in both the overlapping and non-overlapping regions) and the orientation is at 90° (the angle β has a magnitude of 90°), such that the magnets in the stack all form a rectangular cuboid shape, or the cuts and / or incisions are parallel, especially plane-parallel.

[0079] The segmentation directions of the inner and outer magnets can be essentially orthogonal to each other (between 80° and 100°). The inner magnet may only be segmented in the non-overlap region, in which case there is no segmentation in the non-overlap region. However, there may also be complete segmentation of the inner magnet, in which case there is also segmentation of the overlap region.

[0080] The orientation of the segmentation can play a role here. The outer magnet can be segmented circumferentially and / or have an acute angle (less than 45°) between the segment boundaries and the axial direction. This can lead to an acute angle (less than 45°) between the segment boundaries of the inner magnet and the circumferential direction if the segmentation directions of the inner and outer magnets are essentially orthogonal to each other.

[0081] Overall, the embodiment thus shows an angularly offset segmentation of the magnets in a multilayer magnet arrangement, which is also referred to here as a segmentation arrangement. Reference symbol list

[0082] 10 Rotor 11 Axis of rotation 12 Axial direction 13 Radial direction 14 Permanent magnets 15 Double-V arrangement 16 Inner magnet 17 Outer magnet 18 Axis of symmetry 19 Segmentation arrangement 20 Cuts and / or incisions and / or cutouts 21 Electrically non-conductive layer 22 Segmentation direction 23 Segmentation boundaries 24 Non-overlap area 25 Overlap area 26 Outer end of outer magnet 27 Coils 28 Stator

Claims

1. Segmentation arrangement (19) for an inner magnet (16) and an outer magnet (17) of a leg of a double-V arrangement (15) of permanent magnets in a rotor (10) for a permanent magnet electric machine, wherein, in the leg, the inner magnet (16) is arranged further inward, considered in the radial direction (13) with respect to the rotation axis (11), than the outer magnet (17), characterized in that each magnet (16, 17) segmented, which segmentation is substantially characterized by a single direction, wherein the direction is determined by the segmentation boundaries (23), and the segmentation boundaries (23) of the segmentation of the outer magnet (17) have an angle β with an absolute value of 80° to 100° to the segmentation boundaries (23) of the segmentation of the inner magnet (16).

2. Segmentation arrangement (19) according to claim 1, characterized in that the inner magnet (16) is divided into an overlapping region (25) and a directly adjoining non-overlapping region (24), wherein the overlapping region (25) describes an inner radial angular range of the leg in which both the inner magnet (16) and the outer magnet (17) are located, while only the inner magnet (16) is located in the non-overlapping region (24), wherein the inner magnet (16) is segmented only in the non-overlapping region (24).

3. Segmentation arrangement (19) according to claim 2, characterized in that the inner magnet (16) is segmented up to an outer end of the inner magnet (16), wherein the outer end is the end of the inner magnet (16) at which the angle φ between a symmetry axis (18) of the double-V arrangement (15) and the outer end of the inner magnet (16) is maximal.

4. Segmentation arrangement (19) according to claim 1, characterized in that the inner magnet (16) is completely segmented.

5. Segmentation arrangement (19) according to any of the preceding claims, characterized in that a radial direction (13) is perpendicular to an axial direction (12) with respect to the rotation axis (11) and points away from the rotation axis (11), a circumferential direction is perpendicular to the radial direction (13) and the axial direction (12) with respect to the rotation axis (11) and the angle α between the segmentation boundaries (23) of the inner magnet (16) and the circumferential direction has an absolute value α of 0° to 45°.

6. Segmentation arrangement (19) according to claim 5, characterized in that the angle α between the segmentation boundaries (23) of the inner magnet (16) and the circumferential direction is 0°.

7. Segmentation arrangement (19) according to any of claims 4 to 6, characterized in that segmenting the inner magnet (16) involves stacking individual magnets and / or involves cuts and / or notches and / or cutouts (20) over at least 90% of the total area of the inner magnet (16) and thus regions created as a result of the segmentation have a cuboid shape.

8. Segmentation arrangement (19) according to any of the preceding claims, characterized in that the outer magnet (17) is segmented, and the segmentation boundaries (23) of this segmentation have an angle α2 with an absolute value of 0° to 45° to the axial direction (12) with respect to the rotation axis (11).

9. Double-V arrangement (15) comprising two segmentation arrangements (19), characterized in that each segmentation arrangement (19) comprises the features of any of the preceding claims and each forms one leg of the double-V arrangement (15), wherein the segmentation arrangements (19) are designed such that they are symmetrical with respect to the symmetry axis (18) of the legs of the double-V arrangement (15).

10. Rotor (10) for a permanent magnet electric machine comprising at least one double-V arrangement (15) according to claim 9.

11. Permanent magnet electric machine comprising a rotor (10) according to claim 10.