Motor

Abstract

The invention relates to an electric machine (1), comprising a stator (10) and a rotor (20) separated from the stator (10) by an air gap, wherein the rotor (20) has a plurality of shell-shaped magnetic segments (30) fixed to a rotor body (22), wherein the magnetic segments (20) respectively have a plurality of differently magnetically polarized segments (32, 33, 34) along the circumferential direction, wherein the segments respectively form magnetic poles of the rotor (20), and wherein transition zones (36) are formed between the differently magnetically polarized segments (32, 33, 34) of the magnetic segments (30), wherein a gap (40) is provided in the magnetic segments on the side facing the stator (10). It is proposed that the transition zone (36) is formed to extend obliquely along the axial direction of the rotor (20) and is formed in the region of the gap (40).

Description

Technical Field

[0001] The invention relates to an electric machine comprising a stator and a rotor separated from the stator by an air gap. Background Art

[0002] DE 102015212165 A1 discloses an electric machine comprising a stator and a rotor separated from the stator by an air gap, wherein the rotor has shell-shaped magnetic segments. The magnetic segments are arranged opposite each other in pairs and have a plurality of differently polarized segments along the peripheral direction. The differently polarized segments each form the magnetic poles of the rotor. In addition, a gap is provided on the side facing the stator, which serves as a pole lift. Summary of the invention

[0003] The electric machine according to the invention comprises a stator and a rotor separated from the stator, in particular by an air gap, wherein the rotor has at least one, in particular a plurality of, shell-shaped magnetic segments fixed to a rotor body. The magnetic segments each have a plurality of differently magnetically polarized segments. The differently magnetically polarized segments of the magnetic segments are configured along the circumferential direction of the rotor. The differently magnetically polarized segments each form the magnetic poles of the rotor.

[0004] Transition zones are formed between the differently magnetically polarized sections of the magnetic segment, which are distinguished in that they form a non-magnetically polarized structure, in particular a weakly magnetically polarized section. The transition zones are not polarized, in particular intentionally, during magnetic polarization. The transition zones are therefore designed as a non-magnetically polarized or weakly magnetically polarized structure.

[0005] Furthermore, the magnetic segment has one, in particular at least two, recesses, which are characterized in particular in that the spacing of the magnetic segment relative to the stator is enlarged in the region of the recess and / or the thickness of the magnetic segment in the region of the recess is minimized. The recess is arranged on the side facing the stator.

[0006] Advantageously, the transition zone is designed to run obliquely in the axial direction of the rotor. In particular, the oblique course is characterized in that an angle is formed between the transition zone and the axial direction.

[0007] It is also advantageous if the transition zone is formed in the region of the gap. The design of the electric machine according to the invention leads to a minimization of the holding torque, in particular the slot holding torque, and associated with this, to a minimization of the torque ripple. In addition, in particular, the asymmetry of the induced voltage can also be reduced. In addition, the holding torque occurring outside the basic level can be minimized.

[0008] Advantageous developments and improvements of the features described in the invention result from the measures listed in the preferred exemplary embodiments.

[0009] According to an advantageous development, it is provided that the recess extends in the axial direction over the entire magnet segment. The recess extends from the upper side to the lower side of the magnet segment and vice versa.

[0010] Furthermore, it is advantageous if each gap extends completely within the region of the transition zone, viewed in the circumferential direction. Each transition zone is formed completely in the region of the gap. Furthermore, the inclined configuration of the transition zone has the result that two differently magnetically polarized sections separated by the transition zone are also formed at least partially in the magnetic segment in the region of the gap.

[0011] According to one embodiment of the invention, each transition zone extends over the entire width of the recess, the transition zones being formed in the region of the recess of the magnetic segment.

[0012] According to a preferred development of the invention, an in particular tangential edge region of the recess extends in a circumferential direction parallel to the axial direction.

[0013] According to an advantageous embodiment of the invention, the ratio of differently magnetically polarized sections of a magnetic segment to the magnetic segment is 2n+1:1. This results in a minimized slot stop. Furthermore, cost advantages for the electric machine result.

[0014] According to an advantageous embodiment of the invention, the ratio of the width of the differently magnetically polarized segments to the width of the transition zone is between 3 and 5, in particular between 3.5 and 4.5. Preferably, the width of the segment or the width of the transition zone corresponds to the vertical extent along the surface of the magnetic segment starting from the inclined extension. Preferably, the maximum possible value is used as a measure for determining the ratio.

[0015] According to an advantageous embodiment of the invention, it is provided that the magnetic polarization of the segments is designed to be alternating in the peripheral direction. An alternating magnetically polarized pole sequence is produced in the peripheral direction. Preferably, the alternating magnetically polarized pole sequence extends over the area of ​​all magnetic segments.

[0016] According to a preferred embodiment of the present invention, it is provided that the magnetic segment has an additional, in particular a second gap on the side facing the stator. The additional gap is respectively constructed in two edge regions of the magnetic segment, in particular one of the edge bands. The edge region is a region of the magnetic segment that is adjacent to the edge when viewed in the peripheral direction. This involves the following region, which is at the rightmost and / or at the leftmost when viewing the magnetic segment radially. Preferably, the extension of the edge region corresponds to between 1 and 2 times the extension of the additional gap in the peripheral direction.

[0017] An advantageous development is that at least one second transition zone is constructed in each case in the region of the other gaps. The second transition zone extends obliquely in particular in the axial direction. The second transition zone represents a non-magnetically polarized region of the magnetic segment. In addition, the oblique construction of the second transition zone leads to the following result, namely: adjacent differently magnetically polarized segments are also at least partially constructed in the magnetic segment in the region of the gap. According to an development, the second transition zone can be constructed in a triangular shape. Preferably, the second transition zone is constructed in the lower right region and the upper left region of the gap when viewed radially. The second transition zone is constructed in diagonally opposite corners of the magnetic segment. The second transition zone advantageously separates a small magnetically polarized segment from one of the magnetically polarized segments.

[0018] The small magnetically polarized section is in particular designed as a triangle. The small magnetically polarized section is designed in one of the corners of the magnetic segment.

[0019] A particularly advantageous development of the invention is that the further gaps extend in the axial direction over the entire magnetic segment. The further gaps extend from the upper side of the magnetic segment to the lower side and vice versa. It is also advantageous if each further gap extends completely over the second transition zone when viewed in the peripheral direction. Each second transition zone is completely formed in the region of the further gaps.

[0020] An advantageous development is that the second transition zone extends within the scope of a peripheral air gap, which is formed between two magnetic segments in the peripheral direction. The second transition zones of the two magnetic segments and the peripheral air gap form a non-magnetically polarized region, which corresponds to a transition zone between two differently polarized sections of adjacent magnetic segments.

[0021] An advantageous embodiment provides that the transition zones extend parallel to one another. Preferably, all transition zones of one or all magnetic segments have the same angle with respect to the axial direction.

[0022] In one advantageous development, the magnetic segment is designed as a radially or elliptically concave structure on the side facing the stator in the region of the recess or a further recess.

[0023] According to a preferred embodiment of the present invention, it is provided that the magnetic segment has a reduction in thickness of the magnetic segment, which extends in a particularly tangential direction toward the edge of the magnetic segment, on the side facing the stator as viewed in the peripheral direction. Preferably, the air gap expands in the edge region of the magnetic segment. Preferably, the magnetic segment is constructed as a radially or elliptically concave structure in the edge region. Preferably, at least one magnetic segment, in particular all magnetic segments, have an expansion structure of the air gap toward the left and right edges of the magnetic segment when viewed in the radial direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] An exemplary embodiment is shown in the drawings and explained in detail in the following description.

[0025] Figure 1 A perspective view of a stator and a rotor of an electric machine according to the present invention is shown;

[0026] Figure 2 shows a perspective view of a magnetic segment;

[0027] Figure 3 A cross-sectional view of a magnetic segment is shown;

[0028] Figure 4 A three-dimensional view of the stator and rotor of the motor without stator coils is shown;

[0029] Figure 5a shows the profile of the induced voltage with respect to the rotation angle of an electric motor known from the prior art; and Figure 5b The profile of the induced voltage is shown over the rotation angle of the electric machine according to the invention. DETAILED DESCRIPTION

[0030] The electric machine 1 according to the present invention comprises a stator 10 and a rotor 20. Figure 1 1 shows a stator 10 and a rotor 20 of an electric machine 1 according to the invention. Further components of the electric machine 1, such as shafts or axles, control electronics and housing parts, are not shown for reasons of clarity.

[0031] The electric machine 1 is, in particular, an electric motor for driving a fan, preferably a fan for cooling a drive component of a motor vehicle. The electric machine 1 can also be used to drive a fan, in particular in an HVAC system of a motor vehicle.

[0032] The rotor 20 concentrically surrounds the stator 10. Figure 1The rotor 20 is designed to be rotatable relative to the stator 10. Figure 1 The electric machine is designed, by way of example, as an external rotor motor.

[0033] According to one development, the electric machine 1 can also be designed as an internal rotor, wherein the rotor is concentrically surrounded by the stator.

[0034] The stator 10 has a hollow cylindrical base element 12. The base element 12 forms a magnetic grounding element of the stator 10. The stator 10 includes a plurality of, in particular 18, stator teeth 14. The stator teeth 14 are arranged equidistantly within the circumference of the base element 12. The stator teeth 14 extend radially from the base element 12. Slots are formed between the stator teeth 14 in the circumferential direction. The stator teeth 14 do not touch each other. The slots are formed equidistantly. Preferably, a magnetic flux can be generated between the stator teeth 14, which flows through the base element 12.

[0035] Each stator tooth 14 has a tooth bar portion 16 and a tooth tip 18. The winding forms a stator coil 70, at least one stator coil being wound on the tooth bar portion 16. Each stator coil 70 is held at the end by the tooth tip 18 on the one hand and by the base element 12 on the other hand. The movement of the stator coil in or against the radial direction is prevented by the tooth tip 18 and / or the base element 12. The stator coil 70 fills half of the slot adjacent to the stator tooth 14.

[0036] The hollow cylindrical base element 12 and the stator teeth 14 are composed of a plurality of magnetic steel laminations arranged one behind the other in the axial direction and resting against each other. The magnetic steel laminations are joined together, in particular, by means of stamping and stacking.

[0037] By suitable energization of the stator coils, in particular by control electronics, a rotating magnetic field is generated which drives rotor 20. A bridge, in particular a B6 bridge consisting of electrical switches, in particular MOSFETs or transistors, is used for energization.

[0038] The rotor 20 has a rotor body 22 . The rotor body 22 has a magnetic grounding element 24 and a connecting element 26 . The connecting element 26 connects the grounding element 24 to a shaft receptacle 28 .

[0039] The magnetic grounding element 24 is also referred to as a grounding yoke, which is shown, for example, in Figure 1The grounding element 24 is constructed in the shape of a hollow cylinder. The grounding element 24 cooperates with the shaft receiving portion 28 via at least one connecting element 26. The magnetic grounding element 24 and the connecting element 26 form a cylindrical pot. The outer side of the cylindrical pot is formed by the grounding element 24. The bottom of the cylindrical pot is formed by the connecting element 26. The connecting element 26 is especially constructed as a flat, preferably sheet-shaped bottom or has at least one spoke, which connects the hollow cylindrical grounding element 24 to the shaft receiving portion 28. Preferably, the connecting element 26 has a continuously extending gap, especially a hole or a gap, which, for example, reduces the weight of the rotor 20 or improves air circulation or compensates for imbalance.

[0040] Furthermore, the rotor 20 has a plurality of magnetic segments 30. Figure 1 The rotor 20 of the embodiment of the present invention carries four magnetic segments 30 , which are configured as permanent magnetic segments or permanent magnets. The magnetic segments 30 are configured as shells, and the outer peripheries of the magnetic segments match the inner peripheries of the rotor body 22 .

[0041] The magnetic segments, in particular, bear with their radially outer circumference against the inner circumference of the rotor body 22. The rotor body 22 and the magnetic segments are connected to one another, in particular, by means of welding, gluing, soldering, plug-in, screwing or riveting connections or the like.

[0042] The magnetic segment 30 preferably has, in particular, at least two bearing points. The bearing points extend in the axial direction. An adhesive is formed between the bearing points and the rotor body 22 .

[0043] The magnetic segments 30 are arranged equidistantly in the peripheral range. A peripheral air gap 60 is formed between two magnetic segments adjacent in the peripheral direction. The number of the peripheral air gaps 60 corresponds to the number of magnetic segments 30. The outer periphery of the magnetic segment is radially concave. Preferably, the basic shape of the magnetic segment 30 substantially corresponds to a section of a hollow cylinder.

[0044] An air gap is formed between the magnetic segment 30 and the tooth tip 18 .

[0045] exist Figure 2 2 shows a perspective view of the magnetic segment 30. The magnetic segment 30 is shown according to its arrangement on the base body 22. For the sake of simplicity, other components of the electric machine 1 are not shown. The magnetic segment 30 has a plurality of differently magnetically polarized segments 32, 33, 34 in the peripheral direction. The segments are polarized in such a way that a pole sequence is formed in the peripheral direction along the surface facing the stator, that is, north-south-north, etc.

[0046] All magnetic segments 30 of the electric machine 1 are preferably of identical shape. The magnetic segments 30 differ only in the polarization of their individual sections.

[0047] The differently magnetically polarized segments 32, 33, 34 respectively form magnetic poles of the rotor 20. The ratio of the poles of the rotor 20 to the magnetic segments 30 is:

[0048] 2n+1:1;

[0049] Here n represents a natural number. Each magnetic segment 30 has, for example, 3, 5, 7, 9, 11, etc., differently magnetically polarized segments 32, 33, 34, in particular along the circumferential direction. The pole sequence along the circumferential direction is north-south-north or south-north-south. In particular, for a motor 1 with twelve poles on four magnetic segments 30, the motor produces a pole sequence of north-south-north, south-north-south, north-south-north and south-north-south.

[0050] The permanent magnets each have a north pole and a south pole. The segments 32, 33, 34 are polarized so that opposite poles are formed on the surface that is located outside in the radial direction, that is, on the surface facing away from the stator. If, for example, the segment 32 has a magnetic positive pole on the side facing the stator, then the magnetic negative pole is on the side facing away.

[0051] Each of the magnetic segments 30 has edges at the ends of the magnetic segment 30 that are opposite to each other in the peripheral direction. “The edge of the magnetic segment” refers to the left end and the right end of the magnetic segment 30 when viewed in the radial direction. The edge region of the magnetic segment 30 is adjacent to the edge.

[0052] The outer sections 32, 34 viewed in the peripheral direction are substantially of the same size. The sections 32, 34 are each adjacent to the edge of a magnetic segment. The outer sections are each partially formed in the edge region of the magnetic segment 30. Preferably, a magnetic segment 30 is formed in each edge region.

[0053] The section 33 which is located between two outer sections in the peripheral direction is referred to below as the inner section. The inner section is a section which does not adjoin the edge or extends all the way to the edge. All inner sections 33 are also designed to be of equal size. However, in accordance with Figure 1 In the structure, there is only one section 33 located inside.

[0054] “Same size” means in particular that they cover the same surface, in particular the surface of the inner circumference of the magnet segment 30 . “Surface of the inner circumference of the magnet segment” refers to the face of the magnet segment 30 that faces the stator 10 of the electric machine 1 .

[0055] A transition zone 36 is constructed between the differently polarized sections 32, 33, 34. The transition zone 36 is constructed as a non-magnetically polarized structure. In particular, the transition zones are not intentionally magnetically polarized. Nevertheless, they generally have a weaker magnetically polarized structure. Ideally, the transition zone 36 is constructed as a non-magnetically polarized structure. The transition zone 36 does not have the properties of a permanent magnet. The transition zone is not permanently magnetized. The transition zone also forms a pole transition.

[0056] Preferably, the transition zone does not form a transition between the north pole and the south pole of the magnetically polarized segments 32 , 33 , 34 .

[0057] The width 37 of the transition zone has a ratio of between 1:3 and 1:5 to the width 35 of the segment. The width corresponds to the vertical extent along the surface of the magnetic segment 30 starting from the inclined extension.

[0058] The magnetic transition zone 36 in particular forms a separation between the segments 33, 33, 34. The transition zone 36 is designed obliquely, in particular crosswise, along the axial direction of the rotor 20. The transition zone 36 extends obliquely relative to the axial direction of the electric machine 1. An angle alpha is formed between the transition zone 36 and the axial direction. The angle alpha is in particular 18 to 20 degrees, preferably approximately 19 degrees. The angle alpha depends on the inclination angle. The inclination angle is in particular 11 to 13 degrees, preferably approximately 11.8 degrees. The inclination angle depends on the topology of the electric machine 1. Preferably, the angle alpha depends on the topology of the electric machine 1.

[0059] The axial direction z of the rotor 20 extends parallel to the shaft. Preferably, the segments 32, 33, 34 overlap one another in the axial direction. The first transition zones 36 of the magnetic segments 30 extend parallel to one another. The first transition zones 36 of the magnetic segments 30 extend over the entire axial extent of the magnetic segments 30. The first transition zones are designed to be continuous in the radial direction.

[0060] exist Figure 3 The following is shown in Figure 1 and Figure 2 sectional view of a magnetic segment 30. The magnetic segment 30 also has three segments 32, 33, 34. A gap 40 is formed in the region of the first transition zone 36. The gap 40 is formed on the side of the magnetic segment 30 that faces the stator. The gap 40 forms a pole lift in particular. The first transition zone 36 extends in the region of the gap 40. Preferably, the transition zone 36 is formed completely in the region of the gap 40 of the magnetic segment 30.

[0061] According to one development, the recess extends at least over a portion of the first transition zone.

[0062] exist Figure 3 , a magnetic segment 30 is shown having three differently magnetically polarized segments 32, 33, 34. The segments 32, 33, 34 are partially formed in the region of the recess 40. In particular, the inclination of the first transition zone 36 results in an overlap of two adjacent segments in the axial direction.

[0063] According to an optional development of the invention, the two outer sections 32, 34 in the peripheral direction have a contour that is slightly expanded tangentially toward the edge of the magnetic segment 30. The slightly expanded contour leads to the edge region of the magnetic segment 30 that is radially or elliptically concave. In addition, the thickness of the magnetic segment 30 is configured in a manner that decreases tangentially to the edge of the magnetic segment 30. The magnetic segment 30 is preferably configured to be thickest in its center when viewed in the peripheral direction. Preferably, the magnetic segment is thickest in the region of the inner section 33.

[0064] exist Figure 4 2 shows a perspective view of the stator 10 and the rotor 20 of the electric machine 1 without the stator coil 70 . The gap 40 extends in the axial direction of the rotor 20 over the entire magnetic segment 30 .

[0065] Edge regions 42 of the recesses 40 are designed parallel to the axial direction of the rotor 20. In the circumferential direction, each recess 40 extends at least within the extent of the transition zone 36 in the circumferential direction.

[0066] According to one embodiment, the extension of the gap 40 in the circumferential direction corresponds to the extension of the portion 44 of the magnetic segment 30 formed between two gaps 40 in the circumferential direction. The extension of the gap 40 in the circumferential direction of a magnetic segment 30 of the rotor 20, in particular all magnetic segments 30, is the same. The extension of the portion 44 of the magnetic segment 30 formed between two gaps 40 in the circumferential direction is the same.

[0067] According to one embodiment, the extent of all parts of the magnetic segments 30 without recesses 40 or other recesses 50 in the circumferential direction is substantially the same.

[0068] The thickness of the magnetic segment 30 in the region of the recesses 40 is smaller than in the portion 44 between the recesses.

[0069] In the region of the recess 40 , the magnetic segment is designed to be concave. This is shown, for example, in FIG. Figure 3 In the region of the recess 40 , the magnetic segment 30 is in particular designed as a structure which is concave in the radial direction or in an elliptically shaped manner. The recess 40 forms a pole riser.

[0070] The ratio between the width of the sections 32 , 33 , 34 and the width of the transition zone is between 3 and 5 to 1.

[0071] The magnetic polarizations of the sections 32 , 33 , 34 of all magnetic segments 30 alternate with one another in the circumferential direction.

[0072] According to a development of the present invention, the magnetic segment 30 has a further recess 50. Figure 4 , the further recess is shown with the reference numeral 50 . The further recess 50 is formed in the edge region of the magnetic segment 30 .

[0073] The additional gap 50 is formed on the side of the magnetic segment 30 facing the stator 10. The additional gap 50 causes an expansion of the air gap between the rotor 20 and the stator 10. The additional gap 50 extends over the entire axial extent of the magnetic segment 30 in which the gap is formed. The edge region 52 of the additional gap 50 extends parallel to the axial direction. In the region of the additional gap 50, the magnetic segment 30 has a smaller thickness than in the region without the gap 44.

[0074] In the region of the further recess 50 , the magnetic segment 30 has a radially or elliptically concave structure. The radius of the radially concave structure is smaller than the radius of the recess 40 , in particular by ¼ smaller.

[0075] The recess 40 and the further recess 50 form a pole riser.

[0076] A second transition zone 38 is formed in the region of the further recess 50 . The second transition zone 38 is formed so as to extend obliquely in the axial direction. The second transition zone 38 has in particular a triangular shape. In particular, each further recess 50 forms a further transition zone 38 .

[0077] According to one development of the invention, a magnetically polarized section 39 is formed in the corner between the second transition zone 38 and a corner of the magnetic segment 30. Such a section 39 is also formed in the diagonally opposite corners of the magnetic segment.

[0078] exist Figure 2 By way of example, the two second transition zones 38 are each formed in an edge region of the magnetic segment 30 .

[0079] The magnetic segments 30 are separated from one another by a peripheral air gap 60. The mutually adjacent second transition zones 38 of two magnetic segments 30 separated from one another by a peripheral air gap form a further transition zone 37 within the region of the peripheral air gap. The further transition zone 37 extends partially within the region of the two magnetic segments 30 and within the region of the peripheral air gap 60. According to the transition zone 36, the further transition zone 37 also separates two differently magnetically polarized segments, for example according to Figure 2 The sections 34, 32a are separated.

[0080] exist Figure 5a : The induced voltage of an electric motor known from the prior art is shown in FIG. The rotation angle in degrees is shown along the x direction of the diagram. The induced voltage is shown along the y direction. Torque ripples, in particular electric torque ripple ETR (electric torque ripple), depend on the induced voltage.

[0081] In contrast, Figure 5b The induced voltage of the electric machine 1 according to the invention is shown in . The fluctuations in the peak region are absent.

[0082] Overall, the electric machine 1 according to the invention can reduce the braking torque by 50% or more compared to electric motors known from the prior art.

Claims

1. An electric machine (1), comprising a stator (10) and a rotor (20) separated from the stator (10) by an air gap, wherein the rotor (20) has a plurality of shell-shaped magnetic segments (30) fixed to a rotor body (22), and wherein the magnetic segments (30) respectively have a plurality of differently magnetically polarized segments (32, 33, 34) along the circumferential direction, wherein the segments respectively form magnetic poles of the rotor (20), and wherein transition zones (36) are formed between the differently magnetically polarized segments (32, 33, 34) of the magnetic segments (30), wherein gaps (40) are arranged in the magnetic segments on the side facing the stator (10), characterized in that The transition zone (36) is designed to extend obliquely in the axial direction of the rotor (20), and the transition zone (36) is designed in the region of the recess (40), the edge region (42) of which extends in the peripheral direction parallel to the axial direction.

2. The electric machine (1) according to claim 1, characterized in that The gap (40) extends in the axial direction over the entire magnetic segment (30) and in the circumferential direction completely over the transition zone (36).

3. The electric machine (1) according to claim 1 or 2, characterized in that The ratio of the differently magnetically polarized sections (32, 33, 34) of the magnetic segment (30) to the magnetic segment is 2n+1:1, wherein n represents a natural number.

4. The electric machine (1) according to claim 1 or 2, characterized in that The ratio of the width of the segments (32, 33, 34) to the width of the transition zone is between 2 and 2.

5.

5. The electric machine (1) according to claim 1 or 2, characterized in that The magnetic polarization of the segments (32, 33, 34) is designed to alternate along a circumferential direction.

6. The electric machine (1) according to claim 1 or 2, characterized in that The magnetic segment (30) has a further recess (50) on the side facing the stator (10), and a further recess (50) is formed in each of two edge regions of the magnetic segment (30) as viewed in the circumferential direction.

7. The electric machine (1) according to claim 6, characterized in that In the region of the further recesses (50), at least one second transition zone (38) is formed in each case, which second transition zone extends obliquely in the axial direction.

8. The electric machine (1) according to claim 7, characterized in that The further recess (50) extends in the axial direction over the entire magnetic segment (30) and in the circumferential direction completely over the second transition zone (38).

9. The electric machine (1) according to claim 7, characterized in that The second transition zone (38) extends within a peripheral air gap (60) formed between two magnetic segments (30) in the peripheral direction and forms a transition zone between two differently magnetically polarized sections (34, 32a) of adjacent magnetic segments (30).

10. The electric machine (1) according to claim 1 or 2, characterized in that The transition zones (36) extend parallel to one another.

11. The electric machine (1) according to claim 6, characterized in that The magnetic segment (30) is designed as a radially or elliptically concave structure in the region of the recess (40) or a further recess (50) on the side facing the stator (10).

12. The electric machine (1) according to claim 1 or 2, characterized in that The magnetic segment (30) has, viewed in the peripheral direction, an expansion of the air gap on the side facing the stator (10) and extending tangentially toward the edge of the magnetic segment (30), the expansion being designed as a radially or elliptically concave structure.

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