WO2014183843A2

WO2014183843A2 - Rotor for an electromechanical machine

Info

Publication number: WO2014183843A2
Application number: PCT/EP2014/001213
Authority: WO
Inventors: Martin Weinmann; Nicola-Valeriu Olarescu
Original assignee: Diehl Ako Stiftung & Co. Kg
Priority date: 2013-05-15
Filing date: 2014-05-07
Publication date: 2014-11-20
Also published as: EP2997644A2; DE102013020461A1; WO2014183843A3

Abstract

The invention relates to a rotor (1) for an electromechanical machine (62), which rotor is designed to rotate about an axis (5) in relation to a stator (60), comprising a rotor frame (2) and permanent magnets (4), wherein the permanent magnets (4) are inserted into pockets arranged in an azimuthal direction in the rotor frame (2), wherein the permanent magnets (4) are magnetised in the azimuthal direction, and wherein each pair of adjacent permanent magnets (4) face each other with the same pole. According to the invention, the permanent magnets (4) protrude (6) beyond the rotor frame in an axial direction and/or a number of permanent magnets (4) each has a cross-section orthogonal to the axis (5) that is trapezoidal at least in some segments in deviation from a rectangular form. The invention further relates to an electromechanical machine (62), which comprises a stator (60) and such a rotor (1).

Description

Diehl AKO Foundation & Co. KG, 88239 Wangen

Rotor for electromechanical machine

The invention relates to a rotor for an electromechanical machine, which is designed for rotation about an axis with respect to a stator, comprising a rotor frame and permanent magnets, wherein the permanent magnets in pockets, which are arranged in the azimuthal direction in the rotor frame, are introduced, wherein the permanent magnets in azimuthal direction are magnetized, and wherein each two adjacent permanent magnets, each with the same pole face each other. The invention further relates to an electromechanical machine with such a rotor.

In one possible mode of operation for an electromechanical machine, for example for an electric motor, a cylindrical rotor with spoke-like permanent magnets is driven by an electromechanical field generated at a stator. Here, the rotor and a part of the stator on a rotational symmetry with respect to the axis of rotation, with respect to which the rotor, radially surrounded by the stator, is rotatably mounted. The rotor comprises a rotor frame, which is usually made of an axially stacked laminated core. The usually cuboid permanent magnets are usually used with a magnetization in the azimuthal direction in axially continuous, spoke-like circumferential recesses in the rotor frame. Here, two adjacent permanent magnets are each magnetized opposite. In the circumferential direction, therefore, in each case the same magnetic poles of each two magnets facing each other, which forms a rotor pole corresponding polarity in a circular sector of the rotor frame between two permanent magnets.

On the side of the stator facing the rotor, a number of electromechanical poles are arranged rotationally symmetrically with respect to the axis of rotation of the rotor. A pole usually comprises a radial aligned soft iron core, around which a defined number of coil turns of conductor wire is wound, and a radially facing the rotor soft magnetic pole piece, which can be firmly joined to the soft iron core or made in one piece. The pole pieces are each separated from the rotor by a thin air gap. The individual stator magnets can be electronically controlled or commutated by a power supply. In a corresponding driving a stator magnet is generated by the current flow of the coil winding in the soft iron core and thus in the pole piece, a magnetic flux whose field lines are at least partially aligned radially.

The magnetic flux generated by a driven stator magnet in the region of the rotor interacts with the magnetic flux of the individual rotor poles generated by the permanent magnets; This is called a flux linkage. The drive of the rotor via a suitable frequency with respect to the change in the polarity of the stator magnet and thus their respective attractive or repulsive interaction with the voltage applied to the pole shoes rotor poles, the flux linkage, in particular over the pole pieces and the rotor separating air gap away, an important Target for efficiency and the

Performance of the electric motor is. If the maximum torque, the maximum rotational frequency or the maximum power of an electric motor is to be increased, an increase in the magnetic flux linkage, ie the effective magnetic flux, is necessary.

The possible dimensions of an electromechanical machine are usually limited by a higher-level device in which the electromechanical machine is used. For example, the radius of the rotor can often be assumed to be unchangeable size for reasons of structural compactness. A possible axial extension of the rotor and the pole pieces has the disadvantage, with a constant number of turns of the coil windings each to extend the current-carrying conductor wire, whereby the ohmic resistance of the individual coil turns increases, resulting in power losses. Moreover, a higher ohmic resistance in the flow of current releases more heat, which is transmitted to the respective soft iron core and thereby adversely affects its magnetic properties. A possible increase in the number of turns of the individual coil turns at constant axial length of the pole pieces is due to the extension of the respective conductor wire and the concomitant increase in the ohmic resistance as it were. In addition, with increasing number of turns, the inductance of the coil increases, which can lead to an adverse mutual induction.

Furthermore, for the most efficient operation of the electromechanical machine, it is advantageous to minimize the magnetic losses which occur due to the short circuit of the magnetic field over parts of the rotor frame, in particular over the region remote from the stator near a lateral surface.

The magnetic flux of field lines, which connect the two opposite poles of a magnet together, can not contribute to the flux linkage between the rotor field and the stator field due to the field closure; These losses should be limited as far as possible.

The invention has for its object to provide a rotor for an electromechanical machine, which provides the highest possible effective magnetic flux available. Further, the invention has for its object to provide an advantageous application for such a rotor.

The former object is for a rotor for an electromechanical machine, which is designed for rotation about an axis with respect to a stator, comprising a rotor frame and permanent magnets, wherein the permanent magnets in pockets which are arranged in the azimuthal direction in the rotor frame, are introduced Permanent magnets are magnetized in the azimuthal direction, and wherein each two adjacent permanent magnets, each with the same pole face each other, according to the invention achieved in that the permanent magnets protrude in the axial direction over the rotor frame.

At the stator of the electromechanical machine in this case a number of stator poles is provided, wherein a stator pole may be formed as a pole of an electromagnet or as a pole of an electric induction generator. A stator pole expediently comprises a pole shoe, which faces the rotor in the radial direction. In a first step, the invention is based on the fact that the magnetic flux density at a sufficiently smooth surface of a permanent magnet, which is approximately perpendicular to the azimuthal direction and thus magnetization, as substantially, that is, up to negligible edge effects, regardless of the axial Length of the

Permanent magnets is to be assumed, since the permanent magnets can be assumed within the reasonable possibilities as magnetized to saturation. In this case, a sufficiently smooth surface should be understood as meaning, in particular, an edge-free and uniformly either convex or concave or flat surface and approximately perpendicular to the azimuthal direction such that the greatest contribution of the surface normals in the azimuthal direction takes place at each point of the surface. An axial extension of a permanent magnet increases compared to an axially flush with the rotor frame final permanent magnet to the direction of the magnetization approximately perpendicular surface.

Thus, by an axial projection of the permanent magnets due to the uniform flux density at the surfaces of the permanent magnets in the axial direction (with possible variation of the flux density in the radial direction, which is not relevant), the magnetic flux is amplified. This creates, apart from the permanent magnets themselves, no additional material.

The additional axial space requirement for an axial projection is to be set in the low two-digit percentage range based on the axial length of the rotor frame and thus does not represent a decisive obstacle to a compact design.

In a further step, the invention recognizes that due to the high reluctance of the air surrounding the rotor for the magnetic field, which is generated by the axially projecting portions of the permanent magnets, the termination of the field lines on the rotor frame and components of the stator, which in the vicinity of Rotors are arranged, is searched. Especially with a

Rotor frame made of easily magnetizable material, it is energetically unfavorable at an axially projecting portion of a permanent magnet to close the field lines from one azimuthal side to opposite polarity magnetized other side over the surrounding air, since the reluctance is higher there by several orders of magnitude than in the rotor frame. Preferred here is the

Rotor frame made of ferromagnetic, in particular made of soft magnetic material. In the rotor frame, in particular in the case of a rotor frame of easily magnetizable material, rotor poles each having the same polarity of the magnetization of the mutually facing surfaces of each two adjacent permanent magnets, which bound such a rotor pole in the circumferential direction, form in the circular ring sectors between the individual permanent magnets. A described amplification of the magnetic flux in the rotor by the axial projection of two adjacent permanent magnets thus leads to an amplification of the magnetic flux in the corresponding rotor pole. This flux, which is amplified in comparison to axially flush permanent magnets, leads in the region of the rotor pole to an increased magnetic flux density at a lateral surface of the rotor frame facing the stator poles.

If the electromechanical machine is operated as a motor, and correspondingly a stator pole as an electromagnet with approximately radially directed field lines at the radial boundary surface of the stator pole, an axial projection of the permanent magnets results due to the increased flux density at the stator-side lateral surface of the rotor frame in otherwise constant parameters Area of the rotor poles to an increased effective flux between a rotor and a stator pole or for improved Flußverkettung. Likewise, in a generator operation of the electromechanical machine by the increased flux density at a rotor pole, an electrical induction generator of the stator is penetrated by a stronger magnetic flux, which leads to a higher induction voltage.

In a third step, it is recognized that in case of a possible short circuit of the field of a permanent magnet over parts of the rotor frame, the rotor frame is easier to magnetically saturate due to the resulting from the axial projection of the permanent magnets increased flow than without axial projection. As a result, possible efficiency losses of the electromechanical machine are reduced.

In an advantageous embodiment, a soft magnetic material is attached to the axial boundary surfaces of the rotor frame between the axially projecting permanent magnets. The material for the rotor frame is often more expensive than a soft magnetic material, so that a filling of the axial supernatant with soft magnetic material can lead to an overall reduction in production costs. Alternatively, the first object is for a rotor for an electromechanical machine, which is designed for rotation about an axis with respect to a stator, comprising a rotor frame and permanent magnets, wherein the permanent magnets in pockets, which are arranged in the azimuthal direction in the rotor frame, are introduced the permanent magnets are magnetized in the azimuthal direction, and wherein each two adjacent permanent magnets, each with the same pole face each other, according to the invention achieved in that a number of permanent magnets each having an orthogonal to the axis cross-section, which is at least partially trapezoidal deviating from a rectangular shape.

In this case, it is assumed in a first step that, in particular for a substantially annular rotor, with rectangular-shaped permanent magnets, the edge length on the radially inner side represents a limiting factor for constructional reasons. Since the permanent magnets can be assumed to be largely magnetized to saturation, a trapezoidal broadening of a permanent magnet radially outwards with constant magnetization due to the larger volume leads to a larger magnetic moment in the azimuthal direction. If the electromechanical machine is operated as a motor, and correspondingly a stator pole as an electromagnet with field lines oriented approximately radially at the radial boundary surface of the stator pole, a trapezoidal azimuthal widening of the permanent magnets results due to the thereby increased magnetic moment in the azimuthal direction with otherwise constant parameters an increased torque around the axis of rotation.

In a second step, the invention recognizes that a section-wise trapezoidal shape, in particular a trapezoidal taper on the radially outer

End of a permanent magnet, the holder of the permanent magnet simplifies, since by a taper at the radially outer end a pocket for a permanent magnet in the rotor frame requires no additional retaining lugs for its radial securing, but can absorb centrifugal forces occurring on rotation of the rotor to a permanent magnet by positive engagement. The saving of further components for the radial securing of the permanent magnets enables a simpler and less expensive production of the rotor frame. Based on a desired magnetic moment of the permanent magnets as a fixed design parameter is also determined in a third step, since the permanent magnets can be assumed to be magnetized to saturation, a radially outwardly widened or radially inwardly tapered trapezoidal shape of the permanent magnets compared to a Rectangular shape has a shorter edge length at the radially inner end result, and generally azimuthally has less space in the region of the radially inner end of the rotor frame. This widens, compared to a rectangular shape, the circular ring sector between two

Permanent magnets in this area, which also opens the option to use the space gained to another structural change of the rotor frame in this area, which is to suppress the short circuit of the field of a permanent magnet on the rotor frame in this area.

Of course, the initially stated object is achieved by a combination of the aforementioned inventive solutions. Accordingly, it is provided in a further inventive solution that the permanent magnets protrude in the axial direction over the rotor frame, and that a number of permanent magnets in each case one orthogonal to the axis

Cross-section, which is at least partially trapezoidal deviating from a rectangular shape.

Preferably, the rotor frame is made of a stacked in the axial direction laminated core. This suppresses the rotation of the rotor

Generation of eddy currents in axial-radial planes, which can affect the performance of the electromechanical machine by their induced magnetic fields. For this purpose, the individual layers of the laminated core are electrically isolated from each other, for example by a paint.

Conveniently, sintered ferrite magnets and / or plastic-bonded permanent magnets are used as permanent magnets. Such magnets have a relatively high magnetization with respect to the acquisition costs, which has a favorable effect on the production costs.

In an advantageous embodiment, an edge of at least one permanent magnet is chamfered. As a result, the holder of the permanent magnet in the rotor frame can be simplified by a part of the Rotor frame or a firmly attached to the rotor frame material fills the chamfer complementary.

Conveniently, the permanent magnets are pressed into the rotor frame and / or cast. This leads to a simple and fast production process.

In a further advantageous embodiment, at least one axially projecting beyond the rotor frame permanent magnet at least one of its axially projecting side surfaces of one of an axial end plate of the

Blechpaketes axially projecting fold on. The fold exerts a force on the at least one permanent magnet on the side surface and thereby helps to keep it in its position. This is preferably a side surface of the at least one permanent magnet, which is approximately perpendicular to the azimuthal direction. In particular, the at least one permanent magnet can abut against a further axially protruding side surface on a further axially projecting from an axial end plate of the laminated core bending. Preferably, the further axially projecting side surface of the permanent magnet is approximately perpendicular to the azimuthal direction, so that the two respective folds protrude axially from the end plate similar to a wing door and help to keep the permanent magnet azimuthal in its position. By a non-positive connection between the permanent magnet and the folds and radial forces on the permanent magnets, in particular during a rotation of the rotor occurring centrifugal forces, at least partially absorbed.

It may prove to be advantageous if one or each axially projecting fold of the axial end plate comprises a further fold, which rests on the axial end face of the respective permanent magnet. As a result, axial forces on the respective permanent magnets, for example due to an unforeseen impact against the electromechanical machine, can also be absorbed by the or each fold, and the assembly of the respective permanent magnet is simplified.

Conveniently, also has one or each axially projecting fold of the axial end plate on the stator after assembly side facing away in the circumferential direction on a supernatant, which presses the respective permanent magnet radially in the direction of the stator. This also simplifies assembly and further helps to easily hold the respective permanent magnet in its desired position.

It proves to be further advantageous if the rotor frame has a respective recess in the radial direction on a boundary surface of at least one permanent magnet remote from the stator after assembly, such that each radial connecting line passes from a point of the at least one permanent magnet to a lateral surface of the rotor facing away from the stator the respective recess leads. Such a recess impedes the short circuit of the magnetic field of the respective permanent magnet on the rotor frame, since the field from the north pole to the south pole of the permanent magnet must be closed around the recess, and thus less material of the rotor frame is available for short circuit, whereby the material at the same Residual flux density is rather magnetically saturable and thus a magnetization for short-circuit rejects easier than without recess. The suppression of the short circuit thus reduces power losses, as the electromechanical machine is effectively more flux density of a permanent magnet available.

In this case, one or each recess preferably at least partially surrounds the respective permanent magnet at its azimuthal boundary surfaces in the radial direction. This effectively increases the recess and thus extends the distance to be traveled for the short circuit of the field of the respective permanent magnet in the material of the rotor frame while simultaneously reducing the available magnetizable material of the rotor frame. As a result, the short circuit of the field is further complicated, which increases the performance of the electromechanical machine.

Conveniently, a number of resilient brackets is arranged in the recess, which presses the respective permanent magnet radially in the direction of the stator. This helps keep the respective permanent magnet in position in the radial direction with as little material as possible, which could short the field of the permanent magnet. In particular, for this purpose, the or each bracket can be made of the material of the rotor frame or of a dia- or paramagnetic material. Advantageously, a number of gap-like recesses are provided in the rotor frame between two or two adjacent permanent magnets, which are formed into the region of a stator lateral surface of the rotor frame and which extend in the region of the stator lateral surface substantially in the radial direction. The result of this is that the magnetic flux flowing from the mutually facing, unipolarly magnetized surfaces of the respective adjacent permanent magnets can not form any order in the circular sector between the respective permanent magnets, but concentrically focuses radially towards the stator and thus towards the stator poles and thus the magnetic field Flow of himself in this

Reinforced area forming Rotorpols. This leads to a better flux linkage between the rotor and the stator and thus increases the performance of the electromechanical machine. Preferably, the or each recess of the rotor frame is completely or partially filled with a dia- or paramagnetic filler, in particular with a plastic. This further enhances the concentration of magnetic flux of a rotor pole on the stator lateral surface. Conveniently, the dia- or paramagnetic filler at at least one axial end of the rotor at least partially over a number of recesses and is used for balancing the rotor and / or has a shape of a fan blade on. This represents a particularly advantageous multi-purpose use of the filling material, with which the or each recess of the rotor frame is filled or filled. In particular, in this case of axially projecting filler material by a number formed as fan blades projections a fan may be formed, which can be used to cool a further arranged in the vicinity of the electromechanical machine device.

The second object is achieved by an electromechanical machine comprising a stator and a rotor of the type described above. The advantages of the rotor and its developments can be analogously transmitted to the electromechanical machine.

Embodiments of the invention will be explained with reference to drawings. Show Fig. 1 in an oblique view, a rotor with held by folds, axially projecting permanent magnet, Fig. 2 in an oblique view, a rotor with axially projecting

Permanent magnets and a soft magnetic material disposed between the permanent magnets,

3 shows an oblique view of a rotor with trapezoidal permanent magnets around whose radially inner ends in the rotor frame wide recesses are made,

4 shows a plan view of a rotor with sections of trapezoidal permanent magnet, FIG.

5 is an oblique view of a rotor with partially chamfered permanent magnets, which are partially held by brackets, and

Fig. 6 in an oblique view, a rotor with Flußbarrieren, which are filled with a filling material.

In Fig. 1, a rotor 1 is shown in the oblique view, in the rotor frame 2, a number of substantially cuboid permanent magnet 4 is introduced. The permanent magnets 4 are arranged rotationally symmetrically in the rotor frame 2 with respect to an axis 5, which is provided as the axis of rotation of the rotor 1, and each have an axial projection 6 relative to the rotor frame 2. In the radial direction 4 inner recesses 8 and outer recesses 10 are provided in the rotor frame 2 on the permanent magnet. Each two adjacent permanent magnets 4 are magnetized homopolar at the respective mutually facing side surfaces 12, so that in the annular sector 14 of the rotor frame 2 between the permanent magnets 4, a rotor pole 15 of the corresponding polarity is formed. The rotor poles are held by thin webs 16 on an inner ring 18 of the rotor 1.

The rotor frame 2 is made of a laminated core 19 whose axial end plate 20 has axial folds 22, which at the azimuthal Side surfaces 24 of the axial projections 6 of the permanent magnets 4 abut. The protruding from the axial end plate 20 of the laminated core 19 bends 22 have more folds 26 which rest on the axial end faces 28 of the permanent magnets 4. Die Bantinen 22 sind in der axialen Stirnflächen 28 der Permanentmagneten 4 angeordnet. Furthermore, a projection 30, which rests against the axial projection of the inner radial end face 32 of the respective permanent magnet 4, is arranged on the respective radially inner side of each fold 22.

The axial overhang 6 of the permanent magnets 4 increases the available magnetic flux density. Due to the high magnetic

Resistance of the air surrounding the rotor 1, the additional field, which is generated in each case by the axial projection 6, moves to seek a conclusion of the field lines on the rotor 1. In the area of the rotor poles 15, this leads in each case to an increased magnetic flux, which leads to an improved interconnection with the magnetic flux, which is generated by a stator pole (not shown in detail in the drawing).

The inner recesses 8 and the outer recesses 10 reduce the short circuit of the field of a permanent magnet 4 over the

Rotor frame 2. On the inside, such a short circuit can only lead via a web 16 and the inner ring 18 of the rotor frame 2. The web 16 is therefore preferably designed such that it can absorb all occurring on one of him with the inner ring 18 circular ring sector 14 occurring centrifugal forces in a rotation, but this is kept as narrow as possible, so that in the laminated core 19 at the web as quickly as possible a magnetic saturation occurs, which prevents another short circuit of the field.

The folds 22 simplify keeping a permanent magnet 4 azimuthally in position. This can in particular by a non-positive

Connection on the axial projection 6 on both axial sides of the rotor 1 done. In addition, the bends 26 hold the permanent magnet 4 axially in position, and by the projection 30, the permanent magnet 4 is pressed radially outward in the direction of a stator, not shown in detail in the drawing.

In Fig. 2, a rotor 1 is shown with axially over the rotor frame 2 projecting permanent magnet 4 in the oblique view, wherein between the respective axial projection 6 of the permanent magnets 4 circular sectors with soft magnetic material 40 are arranged. The permanent magnets 4 are in this case frictionally held by bracket 42, which each emanate from the web 18, in their position. The soft magnetic material 40 is magnetized in this case, and contributes to the respective rotor pole 15 at. However, since it is usually cheaper than the laminated core 19, from which the rotor frame 2 is made, total costs can be saved.

In Fig. 3, a rotor 1 is shown with trapezoidal permanent magnet 4 in the oblique view. The inner recesses 8 in

Rotor frame 2 in this case partially surround the respective permanent magnet 4 in the radial direction. As a result, the short circuit of the field of a permanent magnet 4 is further complicated because it can lead to the radial inner side only via the extended web 16 to the rotor pole 15 and the inner ring 18. The narrow elongated web 16 can transmit little magnetic flux here due to a slight magnetic saturation occurring, the short circuit of the field is difficult. The permanent magnets 4 are frictionally held in position in the inner recess 8 by comb-like structures 64 which press against the radially inner end face 32. The comb-like structures 64 are at a wedge-shaped area of the

Rotor frame 2 is formed, which is arranged between the recess 8 and trapezoidal permanent magnet 4.

In Fig. 4, a rotor 1 is shown in sections with trapezoidal permanent magnets 4 in sections, which widen radially outwardly trapezoidal first and taper to trapezoidal to the radially outer end. By this taper to the outside, the permanent magnets 4 are positively inserted in the rotor frame 2. Further retaining lugs or stirrups for azimuthal or radial fixation are eliminated.

In Fig. 5, a rotor 1 is shown with axially projecting permanent magnet 4 in the oblique view, which are each provided on the radially inner end face 32 in the axial direction with chamfers 44. The permanent magnets 4 are in the inner recess 8 by brackets 42, each starting from the web 16 and press against the chamfer 44, and by bracket 46, which emanate from the inner ring 18 of the rotor frame 2 and press against the radially inner end face 32, frictionally in Position held. In Fig. 6, a rotor 1 is shown with axially projecting permanent magnet 4 in the circular view, in the circular ring sectors 14 between each two adjacent permanent magnets 4 in the rotor frame 2 as flux barriers gap-like recesses 50 are introduced, which to the outer

Lateral surface 52 of the rotor 1 toward increasingly radially. The flux barriers 50 as well as the inner recesses 8 and the outer recesses 10 are filled with a non-magnetic filling material 54, which protrudes axially over the rotor frame 2 at some locations and is formed there as a fan blade 56. The flux barriers 50 cause a concentration of magnetic flux in the rotor poles 15 to the outer surface 52 of the rotor 1, so that the flux of a rotor pole 15 has an improved interlinkage with the flux of a corresponding stator pole 58 of a stator 60 of the electromechanical machine 62.

LIST OF REFERENCE NUMBERS

1 rotor

2 rotor frames

4 permanent magnet

5 axis

6 axial projection of a permanent magnet

8 inner recess

10 outer recess

12 side surface of a permanent magnet

14 circular ring sector between two adjacent permanent magnets

15 rotor pole

16 bridge to the circular ring sector

18 inner ring of the rotor frame

19 laminated core

20 axial end plate of the rotor frame

22 axial fold

24 azimuthal side surface of the axial supernatant

26 fold

28 axial end face of a permanent magnet

30 projection on a fold

32 radially inner end face of a permanent magnet

40 soft magnetic material

42 stirrups

44 chamfer on a permanent magnet

46 stirrups

50 gap-like recess as a river barrier

52 outer surface of the rotor

54 non-magnetic filler

56 fan blade

58 stator pole

60 stator

62 electromechanical machine

64 comb-like structure

Claims

claims

A rotor (1) for an electromechanical machine (62) adapted to rotate about an axis (5) relative to a stator (60), comprising a rotor frame (2) and permanent magnets (4), said permanent magnets (4) in pockets, which are arranged in the azimuthal direction in the rotor frame (2), are introduced, wherein the permanent magnets (4) are magnetized in the azimuthal direction, and wherein each two adjacent permanent magnets (4), each with the same pole face each other,

characterized,

in that the permanent magnets (4) project beyond the rotor frame in the axial direction (6).

Second rotor (1) for an electromechanical machine (62) which is designed for rotation about an axis (5) with respect to a stator (60), comprising a rotor frame (2) and permanent magnets (4), wherein the permanent magnets (4) in pockets, which are arranged in the azimuthal direction in the rotor frame (2), are introduced, wherein the permanent magnets (4) are magnetized in the azimuthal direction, and wherein each two adjacent permanent magnets (4), each with the same pole facing each other, in particular rotor ( 1) according to claim 1, characterized

in that a number of permanent magnets (4) each have an orthogonal cross-section to the axis (5) which, at least in sections, is trapezoidal in deviation from a rectangular shape.

3. rotor (1) according to claim 1,

characterized,

a soft magnetic material (40) is arranged at the axial boundary surfaces of the rotor frame (2) between the axially protruding permanent magnets (4).

4. rotor (1) according to any one of the preceding claims,

characterized,

that the rotor frame (2) is made of a stacked in the axial direction laminated core (19).

5. rotor (1) according to any one of the preceding claims, characterized

in that sintered ferrite magnets and / or plastic-bonded permanent magnets are used as permanent magnets (4).

6. rotor (1) according to one of the preceding claims,

characterized,

in that at least one edge of at least one permanent magnet (4) is chamfered (44).

7. rotor (1) according to one of the preceding claims,

characterized,

in that one or each permanent magnet (4) is pressed into the rotor frame (2) and / or cast in.

8. Rotor (1) according to one of claims 4 to 7,

characterized,

in that at least one permanent magnet (4) protruding axially beyond the rotor frame (2) rests against at least one of its axially protruding side surfaces (24) by a bent edge (22) projecting axially from an axial end plate (20) of the laminated core (19).

9. rotor (1) according to claim 8,

characterized,

in that one or each axially protruding fold (22) of the axial end plate (20) comprises a further fold (26) which rests on the axial end face (28) of the respective permanent magnet (4).

10. rotor (1) according to claim 8 or claim 9,

characterized,

in that one or each axially protruding fold (22) of the axial end plate (20) has a projection (30) on the side facing away from the stator (60) in the circumferential direction, which protrusion (30) radially adjoins the respective permanent magnet (4) in the direction of the stator (60 ) presses.

11. Rotor (1) according to one of the preceding claims,

characterized,

in that the rotor frame (2) in each case has a recess (8) in the radial direction on an interface (32) of at least one permanent magnet (4) facing away from the stator (60) such that each radial connecting line is from a point of the at least one Permanent magnet (4) to a stator (60) facing away from the lateral surface of the rotor (1) through the respective recess (8).

12. Rotor (1) according to claim 1 1,

characterized,

in that one or each recess (8) at least partially surrounds the respective permanent magnet (4) at its azimuthal boundary surfaces (12) in the radial direction.

13. Rotor (1) according to claim 11 or claim 12,

characterized,

that in the recess (8) a number of resilient brackets (42, 46) is arranged, which presses the respective permanent magnet (4) radially in the direction of the stator (60).

14. Rotor (1) according to one of the preceding claims,

characterized,

a number of gap-like recesses (50) is provided in the rotor frame (2) between two or two adjacent permanent magnets (4) which are formed into the region of a lateral surface (52) of the rotor frame (2) after assembly and which in the region of the stator-side lateral surface (52) extend substantially in the radial direction.

15. Rotor (1) according to any one of claims 1 1 to 14,

characterized,

in that the or each recess (8, 10, 50) of the rotor frame (2) is completely or partially filled with a dia- or paramagnetic filling material (54), in particular with a plastic.

16. Rotor according to claim 15,

characterized,

in that the dia- or paramagnetic filling material (54) partially projects beyond at least one axial end of the rotor (1) over a number of recesses (8, 10, 50) and is used for balancing the rotor (1) and / or a shape a fan blade (56).

17. An electromechanical machine (62), comprising a stator (60) and a rotor (1) according to any one of claims 1-16.