Electric motor

Abstract

An electric motor (1) comprising at least a rotor (2) having a rotation axis (3), and an annular stator (4) surrounding the rotor (2), extending along an axial direction (5) parallel to the rotation axis (3), and having a first end face (6) and a second end face (7) facing in the opposite axial direction (5), wherein the stator (4) has an annular circumferential surface (10) extending between the end faces (6, 7) of the stator (4) and extending in an inward radial direction (11) towards the rotor (2), exactly two stator teeth (8, 9) facing each other about the rotation axis (3), a first stator slot (12) extending along the circumferential surface (10) between the stator teeth (8, 9) and a second stator slot (13) facing the first slot about the rotation axis (3).

Description

[Technical field]

[0001] The present invention relates to an electric motor comprising at least one stator and one rotor, in particular said electric motor being a radial flux motor (RFM). [Background technology]

[0002] EP 2072824 A1 discloses an electric motor for transporting a gaseous or liquid medium. The stator has at least two stator teeth arranged between stator slots. The coils are arranged in the stator slots. The stator slots also serve at least partially as flow openings for the medium.

[0003] When the medium is guided through the stator slot, vortexes of the medium may occur due to the large number of openings and the uneven surface. As a countermeasure, it is possible to design the motor air gap large and use this air gap only as a flow opening. In this case, additional shaping may be useful to maintain the uniformity of the surface.

[0004] However, electric machines with large air gaps face the problem of large stray magnetic fluxes. In known radial flux motors, complex distributed windings are used to reduce the stray magnetic fluxes. This method is costly, especially for machines with small mounting space. Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is therefore to at least alleviate or even to solve the problems outlined with respect to the prior art. In particular, it is intended first of all to embody an electric motor with a compact construction and as large an intermediate space as possible, i.e. in particular also with a cross section as large as possible through which a medium can flow. At the same time, it is intended to ensure the electrical operation of the motor as efficiently as possible. In particular, stray fluxes are kept low and as simple as possible windings are realized.

[0006] An electric motor according to the features of claim 1 is presented in order to achieve these objects. The dependent claims relate to advantageous developments. The features individually recited in the claims can be combined with one another in any technically feasible manner and can be supplemented by details from the description and the drawings, which show further variant embodiments of the invention. [Means for solving the problem]

[0007] The present invention provides an electric motor comprising at least a rotor having a rotation axis and an annular stator surrounding the rotor. The stator extends along an axial direction parallel to the rotation axis and has a first end side and a second end side facing in opposite axial directions (i.e. a first end side facing in a first axial direction and a second end side facing in a second axial direction). The stator has exactly or only two stator teeth, which extend inwardly towards the rotor along a radial direction starting from an annular circumferential surface of the stator extending between the end sides and are mutually opposed about the rotation axis (i.e. a relative position in a mutual relationship via an angle of 180 in the circumferential direction). A first stator slot and a second stator slot opposed about the rotation axis extend between the stator teeth along the circumferential surface. At least one first winding (or a plurality of first windings) is disposed within the first stator slot and at least one second winding (or a plurality of second windings) is disposed within the second stator slot, each winding extending over the end side and radially outward and inward around the annular peripheral surface.

[0008] In particular, at least one first winding is disposed exclusively within the first stator slots, and at least one second winding is disposed exclusively within the second stator slots.

[0009] The stator of the electric motor may in particular comprise a soft magnetic material, such as known as "Soft Magnetic Composite" (SMC), or a combination of electrical plates and SMC, where the SMC material is not sintered; instead, the temperature is controlled below the melting point, but high enough for the core to permanently retain its shape.

[0010] The stator has a substantially annular body (hereinafter also referred to as the periphery) from which two stator teeth extend radially inwards.

[0011] The rotor may have one or more permanent magnets and / or soft magnetic elements. Permanent magnets may preferably be used to form a brushless DC motor, abbreviated as permanently excited synchronous motor or BDLC, whereas soft magnetic elements may be used to produce, for example, a reluctance motor as the electric motor.

[0012] The design of the stator, in particular using SMC, as well as further details regarding the rotor may be found, for example, in WO 2016 / 066714, so that the explanations given therein may also be used to understand and describe said stator.

[0013] The electric motor in particular has a power consumption (i.e. maximum driving power) of less than 20,000 Watts (at rated power), preferably less than 1000 Watts, particularly preferably less than 100 Watts.

[0014] In particular, it is proposed here that the windings do not extend around the stator teeth but around the annular circumferential surface or annular body, in particular that the windings are arranged adjacent to one another along the circumferential direction and that the winding direction runs substantially along the axial and radial directions, and at least when the windings are connected in series, the windings also have a profile component in the circumferential direction.

[0015] In particular, the first winding and the second winding are arranged relative to (or connected to) each other such that current can flow through them in opposite directions.

[0016] This preferred winding arrangement directs magnetic flux through the stator teeth along the annular circumference, i.e., along the circumferential direction, and also along the radial direction.

[0017] In particular, the first winding and the second winding are arranged relative to each other and electrically connected to each other such that magnetic fluxes that can be generated by each winding during operation (of the electric motor) can be directed through the circumferential surface along opposite circumferential directions in the area of ​​the stator slots, meet in the area of ​​the stator teeth, and be directed across the stator teeth and the rotor along the radial direction.

[0018] In particular, the electric motor operates with single-phase alternating current.

[0019] In a first embodiment, the at least one first winding and the at least one second winding are (electrically) connected in parallel with each other.

[0020] In particular, the first winding and the second winding are independent windings.

[0021] In a second embodiment, the at least one first winding and the at least one second winding are (electrically) connected in series with each other, the first winding and the second winding being preferably formed by continuous windings (i.e. designed in one component with each other).

[0022] In particular, multiple windings are disposed within each stator slot, and at least the windings of one stator slot (i.e., the first winding in the first stator slot or the second winding in the second stator slot) are connected in parallel or in series with each other.

[0023] In particular, it is also possible that only a part of the first or second windings of one stator slot are connected in parallel or in series with each other, while the first or second windings of the other stator slots are connected in a different manner. It is also possible to connect different windings with each other in the first stator slot and in the second stator slot.

[0024] In particular, the same number of windings are arranged in the two stator slots.

[0025] A winding in particular extends at least along the axial direction along the circumferential surface and further along the radial direction beyond the end of the annular stator, thereby extending radially beyond the end both outside and inside around the circumferential surface. The individual windings are arranged adjacent to one another along the circumferential direction.

[0026] Due to the arrangement of the windings, with currents flowing in opposite directions in the stator slots separated from each other by the two stator teeth, the magnetic flux is guided along the circumferential direction through the body and through the winding towards the stator tooth, where the magnetic flux (or field lines) leave the winding of the opposite stator slot and are guided along the radial direction through the stator tooth towards the rotor and across the rotor towards the other stator tooth, where the magnetic flux is guided to the body, where it is passed through the winding and further through the body in the circumferential direction. For this reason, the differently polarized ends of each winding, or of the electric conductors forming at least one winding in each stator slot, are maximally spaced apart from each other, so that the stray areas are as small as possible. One end of the electric conductor of the stator slot is arranged in particular in the immediate vicinity of one stator tooth and the other end of the electric conductor is arranged in the immediate vicinity of the other stator tooth.

[0027] In particular, with this embodiment of the electric motor, the stray areas can be kept small and the air gap between the stator teeth and the rotor can be designed to be particularly large, so that the diameter of the rotor can be designed to be small, which allows a large flow cross section to be realized in the electric motor.

[0028] In particular, the rotor has at least one (permanent) magnet (in the circumferential direction) or at least two magnetic poles magnetized in the radial direction (formed on one permanent magnet). The rotor has in particular two poles, a north pole and a south pole, arranged in relative positions in relation to one another, in particular via an angle of 180 degrees along the circumferential direction, and pointing in opposite radial directions.

[0029] In particular, the rotor has two poles and is radially magnetized, in particular the magnetic field lines run along said radial direction in the region of each pole, i.e. in particular the (all) magnetic field lines of one pole run in each case perpendicular (or substantially perpendicular) to the outer circumferential surface of the rotor.

[0030] In particular, the rotor may be annular in shape and thus arranged on a shaft extending through the rotor along the axial direction, the poles in particular constituting a ring portion.

[0031] In particular, the rotor has a boundary between the poles, which boundary extends along the axial direction and along the radial direction, thereby running through a plane that divides the rotor in particular in half.

[0032] This may have the effect that the rotor is oriented relative to the two stator teeth in the non-operating state of the electric motor (i.e. when the windings are not energized) such that the magnetic field lines of the rotor poles are short-circuited by the stator teeth, in particular in such a case that the rotor boundary is aligned with the extent of the two stator teeth in the radial direction.

[0033] However, in this orientation, a torque maximum occurs during the energization of the stator, i.e. during operation of the electric motor, which results in a very good starting behavior of the electric motor, even when operating with single-phase AC.

[0034] In particular, the minimum distance between the outer circumferential surface of the rotor and the inner circumferential surface of the stator teeth is at least 5 mm, in particular at least 10 mm, preferably between 5 mm and 20 mm, particularly preferably between 10 and 15 mm.

[0035] In particular, at least one of the stator teeth, preferably both, particularly preferably both, extend radially inwards towards the rotor from an annular circumferential surface of the stator extending between the end sides to an inner circumferential surface of the stator tooth, along which the stator tooth in particular has a taper in the circumferential direction, i.e. the width of the stator tooth extending in the circumferential direction is at a minimum between the circumferential surface of the stator or of the body and the inner circumferential surface of the stator tooth, the circumferential surface of the body facing radially inwards.

[0036] In particular, the inner peripheral surface of the at least one stator tooth is designed to be wider along the circumferential direction than a region between the peripheral surface of the stator and the tapered portion.

[0037] The stator teeth extend along the radial direction from the circumferential surface or body (or protrusion) of the stator to a first portion toward the tapered portion, and from the tapered portion to a second portion toward the inner circumferential surface.

[0038] In particular, the maximum width of the stator tooth extending along the circumferential direction is at most 50% greater than the width of the tapered portion in the region of the first portion. In particular, the maximum width is greater than 100% and not greater than 150%, preferably greater than 120% and not greater than 150%, of the width of the tapered portion. In particular, the maximum width is located at the transition between the circumferential surface or the annular body and the stator tooth.

[0039] In particular, the second portion extends over a second angular range which exceeds the maximum first angular range of the first portion in the circumferential direction by at least 20%, preferably by at least 50%, particularly preferably by at least 75%, particularly preferably by at least 100% or even by at least 150%, the first and second angular ranges being each determined in particular starting from the rotation axis of the motor.

[0040] In particular, said first angular range extends over an angle of at most 40 degrees, preferably over an angle of at most 25 degrees.

[0041] In particular, said second angular range extends over an angle of at least 50 degrees, preferably over an angle of at least 75 degrees, particularly preferably over an angle of at least 80 degrees.

[0042] In particular, said second angular range extends over an angle of at most 120 degrees, preferably over an angle of at most 100 degrees.

[0043] The first portion extends inwardly from a circumferential surface of the stator or of the body along the radial direction, in particular beyond the at least one winding, until it tapers.

[0044] The first portion in particular constitutes at least 40%, preferably at least 60%, particularly preferably at least 75% of the extension of the stator tooth along the radial direction, and in particular the second portion constitutes at least 5%, preferably at least 10% of the extension.

[0045] In particular, the minimum distance between the outer circumferential surface of the rotor and the inner circumferential surface of at least one stator tooth is more than 50%, in particular more than 75%, preferably more than 80% of the extension of the first portion along the radial direction, in particular at most 150%, preferably at most 120%, particularly preferably at most 100% of the extension of the first portion along the radial direction.

[0046] In particular, the minimum distance between the outer peripheral surface of the rotor and the inner peripheral surface of at least one stator tooth is more than 5%, in particular more than 15%, preferably more than 20% of the maximum outer diameter of the peripheral surface of the stator (or of the body) along the radial direction.

[0047] In particular, the minimum distance between the outer peripheral surface of the rotor and the inner peripheral surface of at least one stator tooth is less than 30%, in particular less than 25%, of the maximum outer diameter of the peripheral surface of the stator (or of the body) along the radial direction.

[0048] In particular, at least one of the stator slots, and preferably both, particularly preferably both, extend along the circumferential direction through a third angular range of at least 120 degrees, preferably at least 150 degrees, and preferably less than 180 degrees, the third angular range being in particular defined starting from the rotation axis of the motor.

[0049] In particular, the at least one winding extending around the circumference of the stator and arranged in only one stator slot extends over a proportion of at least 50%, preferably at least 75%, particularly preferably at least 90% of this third angular range.

[0050] In particular, at least one of the stator teeth, preferably both, particularly preferably both, extend in the axial direction beyond the at least one end side (preferably both end sides) and form a protrusion, which extends in particular over the entire extension width of the at least one stator tooth along the radial direction relative to the at least one end side or the circumferential surface or the body of the stator. Thus, in particular for a constant current, the inner circumferential surface of the at least one stator tooth located on the opposite side to the rotor can be increased in size, so that the magnetic flux density in the region of the inner circumferential surface of the at least one stator tooth can be reduced and the magnetic resistance can be reduced.

[0051] This protrusion can be easily achieved, especially if the stator is made from SMC material rather than stacked metal sheets.

[0052] The projection extends along the axial direction to the windings which form so-called end windings, in particular in the end regions, so that good properties of the electric motor can be achieved, for example in terms of the reluctance, without the physical size of the electric motor being increased by the projection.

[0053] In particular, the bearings of the rotor are arranged outside the stator along the axial direction. In particular, the rotor extends in the axial direction beyond the extent of the stator, i.e. at least beyond the end sides. In particular, the rotor is mounted (at least in the radial direction, possibly additionally in the axial direction) by means of at least one rolling bearing. The rotor is preferably mounted (in the radial direction) on both end sides of the stator.

[0054] In particular, the rotor has a structure for transporting a fluid along the axial direction through an intermediate space formed between the rotor and the stator, and during operation of the motor, the structure moves the fluid, in particular in the axial direction, so that a fluid flow through the intermediate space can be generated.

[0055] As a result of the arrangement of some of the windings outside the intermediate space or outside the stator in the radial direction, the through-flow cross section of the motor or of the intermediate space can be made as large as possible and can be maximized by designing the motor with only two stator teeth.

[0056] The invention further provides a device comprising at least a motor as described above and at least one voltage source, said at least one first winding and said second winding being arranged relative to one another and (electrically) connected to one another such that a current can flow through them in opposite directions.

[0057] In particular, the first winding and the second winding are arranged relative to each other and electrically connected to each other such that magnetic fluxes that can be generated by each winding during operation of the electric motor can be directed through the circumferential surface along opposite circumferential directions in the area of ​​the stator slots, meet in the area of ​​the stator teeth, and be directed across the stator teeth and the rotor along the radial direction.

[0058] Statements made with respect to the motor specifically apply equally to the device and vice versa.

[0059] It is noted that the numerical terms used herein (such as "first", "second", "third", etc.) primarily (exclusively) serve to distinguish between several similar objects, dimensions or steps, i.e., do not necessarily predefine dependencies and / or sequences of the objects, dimensions or steps. If dependencies and / or sequences are necessary, they will be explicitly stated herein or will be obvious to those skilled in the art from examining the specifically described embodiments.

[0060] The present invention and technical field will be described in more detail below based on the drawings. It is pointed out that the present invention is not intended to be limited by the disclosed exemplary embodiments. In particular, unless explicitly indicated, it is also possible to extract partial aspects of the important matters discussed in the drawings and combine them with findings from this specification and / or the drawings and other components. The same reference symbols are used to indicate the same objects. This allows the explanations from other drawings to be taken into consideration supplementarily where appropriate. The drawings are shown in each case diagrammatically. [Brief description of the drawings]

[0061] [Figure 1] 1 shows a perspective, partially cut away view of a device with an electric motor; [Diagram 2] 2 shows an electric motor of the device according to FIG. 1 along its axis of rotation; [Diagram 3] 3 shows the electric motor according to FIG. 2 along the axis of rotation with the paths of magnetic flux. [Figure 4] 2 and 3 show perspective views of the electric motor. [Diagram 5] A graph is shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0062] Figure 1 shows a perspective, partially cut-away view of an arrangement 25 with an electric motor 1. Figure 2 shows the electric motor 1 of the arrangement 25 according to Figure 1 along the axis of rotation 3. Figure 3 shows the electric motor 1 according to Figure 2 along the axis of rotation 3 with the path of the magnetic flux 30. Figure 4 shows a perspective view of the electric motor 1 according to Figures 2 and 3. Figures 1 to 4 are explained together in the following text.

[0063] The electric motor 1 comprises a rotor 2 having a rotation axis 3 and an annular stator 4 surrounding the rotor 2 and arranged coaxially therewith. The stator 4 extends along an axial direction 5 parallel to the rotation axis 3 and has a first end side 6 and a second end side 7 facing in the opposite axial direction 5. The stator 4 has exactly two stator teeth 8, 9 which extend inwardly towards the rotor 2 along a radial direction 11 starting from an annular peripheral surface 10 of the stator 4 extending between the end sides 5, 6 and are opposed to one another about the rotation axis 3 (i.e. in a relative position relative to one another via an angle of 180 in the circumferential direction 27). A first stator slot 12 and a second stator slot 13 opposed to the rotation axis 3 extend along the peripheral surface 10 between the first stator tooth 8 and the second stator tooth 9. A plurality of first windings 14 are disposed within the first stator slot 12 and a plurality of second windings 15 are disposed within the second stator slot 13, with each winding 14 extending over the end sides 6, 7 and outwardly and inwardly in a radial direction 11 around the annular circumferential surface 10. In Figures 1 to 3, the portions of each of the windings 14, 15 that extend along the end sides 6, 7 in the radial direction 11 have been cut away and are not shown. The complete windings 14, 15 are only shown in Figure 4.

[0064] The windings 14, 15 do not extend around the stator teeth 8, 9, but only around the annular circumferential surface 10. The individual windings 14, 15 are disposed adjacent to one another along the circumferential direction 27.

[0065] The first winding 14 and the second winding 14, 15 are arranged relative to each other and electrically connected to each other such that magnetic fluxes 30 that can be generated by the respective windings 14, 15 during operation of the electric motor 1 can be directed through the peripheral surface 10 (the body of the stator 4) along opposite circumferential directions 27 in the area of ​​the stator slots 12, 13, meet in the area of ​​the stator teeth 8, 9 and be directed across the stator teeth 8, 9 and the rotor 2 along the radial direction 11.

[0066] In this specification, the first winding 14 and the second winding 15 are connected in parallel with each other. The first winding 14 and the second winding 15 are windings 14, 15 independent of each other.

[0067] A plurality of windings 14, 15 are disposed in each stator slot 12, 13, and the windings 14, 15 of the stator slots 12, 13 (i.e., the first winding 14 of the first stator slot 12 or the second winding 15 of the second stator slot 13) are connected in series with each other (see FIG. 1). Therefore, here, the first windings 14 are connected directly with each other. Also, the second windings 15 are connected directly with each other. The first windings 14 and the second windings 15 are connected in parallel with each other.

[0068] Here, an equal number of windings 14, 15 are arranged in the two stator slots 12, 13.

[0069] One winding 14, 15 extends at least along the axial direction 5 along the circumferential surface 10 (i.e., outside and inside the circumferential surface 10) and further along the radial direction 11 beyond the end sides 6, 7 of the annular stator 4, thereby extending radially 11 outwardly and inwardly around the circumferential surface 10 beyond the end sides 6, 7.

[0070] Due to the arrangement of the windings 14, 15 with currents 16 flowing in opposite directions in the stator slots 12, 13 separated from one another by two stator teeth 8, 9, the magnetic field lines (or magnetic flux 30) are directed along the circumferential direction 27 through the body of the stator 4 and through the windings 14, 15 towards the stator teeth 8, 9. At the first stator tooth 8, the magnetic field lines (magnetic flux 30) are directed from the windings 14, 15 of the opposing stator slots 12, 13 and along the radial direction 11 through the upper stator tooth 8 towards the rotor 2 and across the rotor 2 towards the second stator tooth 9. At the second stator tooth, the magnetic field lines (magnetic flux 30) are directed towards the body of the stator 4 where they pass through the windings 14, 15 further in the circumferential direction 27 through the body of the stator 4. The differently polarized ends of the electrical conductors forming each winding 14, 15, or at least one winding 14, 15 in each stator slot 12, 13, are maximally spaced apart from one another, so that the stray areas are as small as possible. One end of said electrical conductors of the stator slot is in particular arranged in the immediate vicinity of one stator tooth 8, 9 and the other end in the immediate vicinity of the other stator tooth 9, 8 (see FIG. 1).

[0071] In this embodiment of the electric motor 1, the stray areas can be kept small and the air gap 18 between the stator teeth 8, 9 and the rotor 2 can be designed to be particularly large. The diameter of the rotor 2 can therefore be designed to be small, which allows the intermediate space 24 of the electric motor 1 to have a large through-flow cross section.

[0072] The stator teeth 8, 9 start from an annular circumferential surface 10 of the stator 4 extending between the end sides 6, 7 and extend inwardly along the radial direction 11 towards the rotor 2 to the inner circumferential surface 20 of the stator teeth 8, 9. Along this extension width 33, the stator teeth 8, 9 have a tapered portion 34 in the circumferential direction 27. That is, the width of the stator teeth 8, 9 extending in the circumferential direction 27 is minimum between the circumferential surface 10 of the stator 4 facing inwardly along the radial direction 11 and the inner circumferential surface 20 of the stator teeth 8, 9.

[0073] The inner circumferential surface 20 of the stator teeth 8 , 9 is designed to be wider along the circumferential direction 27 than the area of ​​the stator teeth 8 , 9 between the peripheral surface 10 of the stator 4 and the tapered portion 34 .

[0074] The stator teeth 8 , 9 extend along a radial direction 11 from the peripheral surface 10 of the stator 4 to a first portion 35 towards the tapered portion 34 , and from the tapered portion 34 to a second portion 36 towards the inner peripheral surface 20 .

[0075] The second portion 36 extends in the circumferential direction 27 over a second angular range 38 of about 90 degrees. The second angular range 38 exceeds the maximum first angular range 37 of the first portion 35 of about 30 degrees by about 200%. The angular ranges 37, 38 are determined starting from the rotational axis 3 of the motor 1.

[0076] The first portion 35 originates at the peripheral surface 10 of the stator 4 and extends inwardly in the radial direction 11 past the windings 14 , 15 to the tapered portion 34 .

[0077] The first portion 35 constitutes approximately 75% of the extension 33 of the stator teeth 8 , 9 along the radial direction 11 .

[0078] The two stator slots 12, 13 each extend along the circumferential direction 27 over a third angular range 39 that is an angle of approximately 150 degrees.

[0079] At least one winding 14 , 15 extending around the periphery 10 of the stator 4 and arranged in only one stator slot 12 , 13 extends over approximately 97% of this third angular range 39 .

[0080] The rotor 2 has two poles 17 of permanent magnets (adjacent to each other along the circumferential direction 27). The two poles 17 are each magnetized in a radial direction 11 (see FIG. 2). The poles 17 are arranged in relative positions relative to each other via an angle of 180 degrees along the circumferential direction 27 and point in opposite radial directions 11. The poles 17 are separated from each other by a boundary (dashed line in FIG. 2) which here extends across the extension width 33 of the stator teeth 8, 9.

[0081] The minimum distance 18 between the outer circumferential surface 19 of the rotor 2 and the inner circumferential surfaces 20 of the stator teeth 8, 9 is at least 5 millimeters.

[0082] 1 and 4, the stator teeth 8, 9 extend beyond the two end sides 6, 7 along the axial direction 5, thereby forming a protrusion 40 at each end side 6, 7. This protrusion 40 extends over the entire extension width 33 of the respective stator tooth 8, 9 along the radial direction 11. Due to this, the inner circumferential surface 20 of each stator tooth 8, 9 located facing away from the rotor 2 may increase in size, so that under a given current, the magnetic flux density in the region of the inner circumferential surface 20 of the stator tooth 8, 9 may decrease, thereby reducing the magnetic resistance.

[0083] The bearings 21 of the rotor 2 are arranged outside the stator 4 along the axial direction 5. The rotor 2 (and in particular not the magnet poles 17) extends in the axial direction 5 beyond the extent of the stator 4, i.e. at least beyond the end sides 6, 7, here the first end side 6. The poles 17 could also extend beyond the extent of the stator 4, which could result in increased torque.

[0084] The rotor 2 has a structure 22 for transporting a fluid 23 through an intermediate space 24 formed between the rotor 2 and the stator 4 along the axial direction 5. During operation of the motor 1, the structure 23 moves the fluid 23 in the axial direction 5 such that a fluid flow through the intermediate space 24 may be generated.

[0085] The device 25 shown in Fig. 1 comprises the motor 1 and a voltage source 26. The voltage source 26 is in particular a sinusoidal (and not a DC) source, a switchable voltage source or an electronics system. The first windings 14 and the second windings 15 are arranged relative to one another and connected such that a current 16 can flow through them in opposite directions, so that a magnetic flux 30 is directed starting from the poles 17 of the magnet, across the stator teeth 8, 9 in the radial direction 11, towards the circumferential surface 10 of the stator 4 and through the circumferential surface 10 of the stator 4 along the circumferential direction 27.

[0086] Figure 5 shows a graph. The rotational speed 29 of the electric motor 1 in revolutions per minute is plotted on the horizontal axis. The torque 28 that can be generated by the electric motor 1 is plotted in Newton meters on the vertical axis. A first profile 31 shows the torque 28 of an electric motor 1 according to another configuration. A second profile 32 shows the achievable torque 28 of the electric motor 1 described here, which is higher at almost all operating points. [Explanation of symbols]

[0087] 1 Motor 2 Rotors 3 Rotation Axis 4 Stator 5 Axial Direction 6 First end side 7 Second end side 8 First Stator Tooth 9 Second stator tooth 10 Circumferential surface 11 Radial 12 First Status Slot 13 Second Stator Slot 14 First Winding 15 Second Winding 16 Current [amperes], i.e. [A] 17 poles 18 distance 19 Outer surface 20 Inner surface 21 Bearings 22 Structure 23 Fluid 24 Intermediate Space 25 Equipment 26 Voltage Source 27 Circumferential direction 28 Torque [Newton metres], i.e. [Nm] 29 Rotational speed is [revolutions per minute], or [rpm] 30 Magnetic flux [tesla squared], or [T * m 2 ] 31 First Profile 32 Second Profile 33 Extension width 34 Tapered section 35 First part 36 Second part 37 First Angle Range 38 Second Angle Range 39 Third Angle Range 40 Protrusion

Claims

1. An electric motor (1) comprising at least a rotor (2) having a rotation axis (3), and an annular stator (4) surrounding the rotor (2), extending along an axial direction (5) parallel to the rotation axis (3), and having a first end side (6) and a second end side (7) each facing in the opposite axial direction (5), the stator (4) has exactly two stator teeth (8, 9) which extend inwardly towards the rotor (2) in a radial direction (11) starting from an annular peripheral surface (10) of the stator (4) extending between the end sides (6, 7) and are opposed to one another with respect to the axis of rotation (3); The two stator teeth (8, 9) a first portion (35) including a tapered portion (34) whose width in a circumferential direction (27) gradually decreases from the annular circumferential surface (10) toward the rotor (2) within a first angle range (37); a second portion (36) whose width in the circumferential direction (27) extends from an end portion on the inner peripheral surface side of the first portion (35) toward the rotor (2) within a second angular range (38); having the second angular range (38) in the circumferential direction (27) is 20% greater than the first angular range (37); a first stator slot (12) and a second stator slot (13) opposed to the rotation axis (3) extend along the peripheral surface (10) between the stator teeth (8, 9); A first winding (14) is wound around the stator (4) within the first stator slot (12), and a second winding (15) is wound around the stator (4) within the second stator slot (13), a portion of each of the first winding (14) and the second winding (15) is located in a gap between the annular circumferential surface (10) and the second portion (36) of the stator teeth (8, 9); the first winding (14) and the second winding (15) extend over the end sides (6, 7) and around the annular circumferential surface (10) outwardly and inwardly in the radial direction (11); An electric motor (1), wherein the shortest distance (18) between the outer circumferential surface (19) of the rotor (2) and the inner circumferential surface (20) of the second portion (36) of the stator teeth (8, 9) is between 10 and 20 millimeters.

2. 2. The motor (1) according to claim 1, wherein the first winding (14) and the second winding (15) are arranged in relation to each other and electrically connected to each other such that magnetic fluxes (30) which may be generated by each of the windings (14, 15) during operation are directed through the circumferential surface (10) along opposite circumferential directions (27) in the region of the two stator slots (12, 13), meet in the region of the stator teeth (8, 9) and can be directed across the stator teeth (8, 9) and the rotor (2) along the radial direction (11).

3. 3. The motor (1) according to claim 2, wherein the first winding (14) and the second winding (15) are connected in parallel with each other.

4. 3. The motor (1) according to claim 2, wherein the first winding (14) and the second winding (15) are connected in series with each other.

5. A plurality of the windings (14, 15) are disposed in the two stator slots (12, 13), respectively; 5. The motor (1) according to claim 1, wherein the windings (14, 15) of one stator slot (12, 13) are connected in parallel or in series with each other.

6. 6. The motor (1) according to claim 1, wherein at least one of the stator teeth (8, 9) extends beyond the at least one end side (6, 7) along the axial direction (5) and forms a protrusion (40).

7. 7. The motor (1) according to any one of claims 1 to 6, wherein the rotor (2) has a structure (22) for transporting a fluid (23) through an intermediate space (24) formed between the rotor (2) and the stator (4) along the axial direction (5).

8. 8. An apparatus (25) comprising at least a motor (1) according to any one of claims 1 to 7 and at least one voltage source (26), the first winding (14) and the second winding (15) being arranged and connected relative to one another such that a current (16) can flow through them in opposite directions.

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