Rotor with magnetic flux transfer unit

Abstract

Rotor (1) for an electric motor (100), wherein the rotor (1) is designed as a hollow body, in particular a hollow cylinder, the outer surface (300) of which surrounds a central axis (8) of the rotor (1) and the cavity (3) of which extends from a top surface (400) to a base surface (500) along the central axis (8), and the outer surface (300) of the rotor (1) has at least one first pair of recesses (200), wherein ◯ a first recess and a second recess of the first pair of recesses (200) are arranged opposite each other, and ◯ in the first recess of the first pair of recesses (200) a first rotor magnet (2) designed as a north pole is arranged precisely and in the second recess of the first pair of recesses (200) a second rotor magnet (2) designed as a south pole is arranged precisely, characterized in that a first magnetic flux transmission unit (5), in particular a first soft iron bridge, is arranged between the first recess and the second recess of the first pair of recesses (200) such that, when the first rotor magnet (2) and / or the second rotor magnet (2) is exposed to a magnetic field provided by a stator (110) of the electric motor (100), a magnetic flux (20) is provided between the first rotor magnet (2) and the second rotor magnet (2).

Description

Field of the invention

[0001] The present invention relates to a permanent magnet rotor with a magnetic flux transmission unit and a switched reluctance motor consisting of such a rotor and a stator matched thereto. Background of the invention

[0002] Electric motors are used in a wide variety of applications, and thus a wide variety of designs are known. Due to the high power and torque they can achieve, electric motors are particularly in demand in electromobility, among other applications.

[0003] Switched reluctance motors have a different number of salient poles on the rotor and stator. The poles on the rotor are often formed by permanent magnets made of a hard magnetic material, while the stator legs are magnetized by electrical coils. The legs on the stator, also called stator teeth, are alternately switched on and off. The magnetic field generated by the energized windings of the legs attracts the nearest pole of the rotor and is switched off as soon as (or shortly before) the rotor pole is opposite the stator leg that is attracting it. In this position, another stator leg is energized, creating further interaction between a pole and the leg, and the rotor is attracted again in the same direction of rotation. Although reluctance motors are often designed with three or more phases, designs with two or just one phase are also available.

[0004] Permanent magnets are manufactured by magnetizing a hard magnetic material through the action of a magnetic field. While soft magnetic materials lose their magnetization once the external magnetic field is removed, hard magnetic materials retain this magnetization. To achieve particularly strong permanent magnets, rare earth elements such as neodymium or samarium are often used, particularly due to their high magnetic remanence flux density and high magnetic coercive field strength. These are known, for example, as neodymium-iron-boron (Nd2Fe). 14 B) Alloy or samarium-cobalt (SmCo5 and Sm2Co 17 ) Alloy is often used in the production of electric motors.

[0005] The mining of rare earths is associated with high economic costs and environmentally harmful processes. Furthermore, a large portion of the rare earths marketed worldwide are mined by a few individual countries. This creates a dependency on the producers who use rare earths in their products.

[0006] DE202023101234 U1 of the prior art solves the described problem by designing a rotor that can be produced without rare earths.

[0007] However, there are further disadvantages that are not addressed by the current state of the art. Due to the heterogeneous design of the rotors, particularly the separate construction of the rotor magnets, the rotor magnets can become loose due to centrifugal force, especially at high speeds. Furthermore, the high power and high torque required for various applications can only be achieved with state-of-the-art electric motors, especially when their rotors feature permanent magnets without rare earth elements, using large and therefore heavy designs. Object of the invention

[0008] It is therefore an object of the invention to provide a rotor for an electric motor and such an electric motor which overcome the disadvantages of the prior art.

[0009] Another task is to provide a rotor that is suitable for use at high speeds.

[0010] Another task is to provide an electric motor that operates efficiently, powerfully and / or smoothly.

[0011] These objects are achieved by implementing at least some of the characterizing features of the independent patent claims. Features that further develop the invention in an alternative or advantageous manner can be found in some of the remaining features of the independent patent claims and the dependent patent claims. Summary of the invention

[0012] A first aspect of the invention relates to a rotor for an electric motor, wherein the rotor is designed as a hollow body, in particular a hollow cylinder. An (outer) lateral surface of the hollow body encircles a central axis of the rotor, and a hollow space of the hollow body extends from a top surface to a base surface along the central axis.

[0013] The outer surface of the rotor has at least a first pair of recesses, wherein a first recess and a second recess of the first pair of recesses are arranged opposite one another. In the first recess of the first pair of recesses, a first rotor magnet designed as a north pole (towards the outer surface / towards the outer circumference of the rotor / towards the outside) is precisely arranged, and in the second recess of the first pair of recesses, a second rotor magnet designed as a south pole (towards the outer surface / towards the outer circumference of the rotor / towards the outside) is precisely arranged. Optionally, the first recess and the second recess of the first pair of recesses can each extend from the top surface to the base surface.

[0014] The rotor is configured such that a first magnetic flux transmission unit is arranged between the first recess and the second recess of the first pair of recesses such that, when the first rotor magnet and / or the second rotor magnet is exposed to a magnetic field provided by a stator of the electric motor, a magnetic flux is provided between the first rotor magnet and the second rotor magnet (via the magnetic flux transmission unit / through the magnetic flux transmission unit / along the magnetic flux transmission unit). In a specific embodiment, this magnetic flux transmission unit can be formed by a first soft iron bridge.

[0015] A magnetic flux transfer unit is characterized by being made of a material with the highest possible magnetic saturation flux density and high magnetic permeability. This bundles and guides the magnetic flux generated when current flows through the coil's electrical conductor with minimal loss, thus increasing the inductance. In other words, the magnetic flux transfer units are made of a material whose ratio of magnetic flux density to magnetic field strength favors a magnetic flux of 20.

[0016] The inventive design of the rotor has the advantage that the magnetic flux transmission units promote a magnetic flux between the rotor magnets of a pair of recesses arranged opposite one another. Among other things, this promotes a better hold of the rotor magnets, which are formed separately from the rotor itself, and which are thus held in the recesses and thus in the rotor even at high centrifugal forces or at high speeds. Optionally, the rotor magnets can be glued into the recesses (e.g., with a suitable universal adhesive, a two-component adhesive / epoxy resin, or a casting resin, also called potting resin), and / or soldered to the recesses.Alternatively or in addition to this possibility of holding the rotor magnets in the rotor recesses, rotor magnets can be used that have a larger diameter than the diameter of the recesses (in other words, the rotor magnets have an axial oversize compared to the recesses). These (larger) rotor magnets can then be pressed into the (narrower) recesses (therefore, a press fit is created). Optionally, the rotor recesses can also be made deeper. These optional holders for the rotor magnets have the further advantage that the rotor can be operated with a very small (magnetic) gap to the stator or to the stator magnets, thereby increasing the torque, power, and efficiency of the electric motor according to the invention without the risk of the rotor magnets being torn from the recesses due to the increased torque and the acting magnetic field.Furthermore, the magnetic flux provided by the magnetic flux transmission unit through the rotor contributes to the fact that the rotation of the rotor in an electric motor according to the invention can be provided more uniformly (in other words, "smoother"), with lower (friction) losses and thus more efficiently and with a higher torque and thus an improved performance compared to rotors or electric motors of the prior art.

[0017] In an exemplary embodiment of the rotor according to the invention, the outer surface of the rotor can have a second and a third pair of recesses. Thus, the rotor can have a total of six recesses, wherein the six recesses can be offset radially by 60 degrees relative to the central axis of the rotor (along the circumference of the rotor during rotation about the central axis / rotation axis), whereby an equal distance can be maintained between each two adjacent recesses along the outer surface.

[0018] In a further embodiment, a third rotor magnet designed as a north pole (towards the lateral surface / towards the outer circumference of the rotor / towards the outside) and a fourth rotor magnet designed as a south pole (towards the lateral surface / towards the outer circumference of the rotor / towards the outside) can be arranged in the second pair of recesses, and a fifth rotor magnet designed as a north pole (towards the lateral surface / towards the outer circumference of the rotor / towards the outside) and a sixth rotor magnet designed as a south pole (towards the lateral surface / towards the outer circumference of the rotor / towards the outside) can be arranged in the third pair of recesses in such a way that rotor magnets designed as north poles and rotor magnets designed as south poles alternate along the lateral surface.By arranging the six magnets on the outer surface of the rotor, a magnetic ring arranged inside the cavity, which consists of a large number of magnets and is therefore more resource-intensive, can be dispensed with and a high speed and power can still be achieved with simultaneous, uniform rotation.

[0019] In a further embodiment of the invention, the rotor 1 can have a second and a third magnetic flux transmission unit, which in some embodiments can be formed in particular by a second and a third soft iron bridge. The second magnetic flux transmission unit can be arranged between the recesses of the second pair of recesses and the third magnetic flux transmission unit can be arranged between the recesses of the third pair of recesses. Furthermore, the first, second and third magnetic flux transmission units can be offset from one another in the axial direction of the center axis of the rotor. This embodiment has the advantage that all six rotor magnets are held firmly on the rotor by the magnetic fluxes transmitted via the three magnetic flux transmission units, even at high speeds.

[0020] In a further embodiment of the invention, the respective recess of a respective pair of recesses can have a separating component 19, in particular a casting resin. The separating component can be arranged between the respective recess and the rotor magnet arranged in the respective recess. In certain embodiments, the separating component can have an electrically insulating effect. This embodiment has the advantage that the rotor magnets are additionally held to the rotor by the casting resin. In certain embodiments, the separating component can be formed as an epoxy resin.

[0021] In a further embodiment, the rotor magnets can be attached to the rotor with a mechanical connection. Said mechanical connection is preferably designed such that, during rotation of the rotor, it counteracts a force acting radially outward from the central axis (for example, a centrifugal force). For example, the mechanical connection can comprise a screw that fixes the rotor magnet to the rotor in the radial direction. Another example includes a soldered connection. An advantage of such an embodiment is that high speeds can be achieved despite the associated high centrifugal forces, since the rotor magnets are additionally secured against loosening by the mechanical connection.It should be noted that in certain embodiments, sufficient holding forces can be generated by a mechanical connection that is comparatively small, comparable to the size of the entire rotor magnet, without significantly impairing the desired magnetic effect of the rotor magnets. Another embodiment involves connecting the mechanical connection to the magnetic flux transmission unit.

[0022] In a further embodiment of the invention, mechanical holding elements can be arranged within the cavity, which are provided to interact with matching holding element counterparts of a rotation receiving unit inserted into the cavity of the rotor in such a way that when the rotor rotates about a first rotation axis running coaxially to the center axis of the rotor, the rotation receiving unit is also rotated about the first rotation axis.

[0023] In a further embodiment of the invention, the respective magnetic flux transmission unit can comprise the mechanical retaining elements. This eliminates the need to subsequently insert the retaining elements into the rotor cavity, thus eliminating a production step.

[0024] In a further embodiment of the invention, the mechanical retaining elements can form a toothed hub, wherein the toothed hub is designed to interact with a rotation-receiving unit designed as a toothed shaft. Thus, the rotor can be used for common electric motors that are operatively connected to a drive shaft (e.g., in a drive for electric cars).

[0025] In a further embodiment of the invention, a respective rotor magnet arranged in a respective recess can comprise the compound iron oxide. Optionally, in certain embodiments, the respective rotor magnet can be made of iron oxide. This embodiment has the advantage that the rotor magnets can be manufactured from a cost-effective, more environmentally friendly, and globally available material. Alternatively or additionally, said rotor magnet can comprise at least one rare earth metal. Optionally, in certain embodiments, the respective rotor magnet can be made of the at least one rare earth metal.

[0026] A second aspect of the invention relates to an electric motor comprising a rotor according to one of the above-mentioned embodiments (according to one of claims 1 to 9) and a stator. The stator has a first and a second stator magnet pair. The stator magnets of the first stator magnet pair are arranged opposite one another on the rotor, and the stator magnets of the second stator magnet pair are arranged opposite one another on the rotor and offset by 90 degrees from the first stator magnet pair. Furthermore, the respective stator magnets are U-shaped. In addition, one leg of each U-shaped stator magnet is integrally formed on the rotor and has a coil. The coil is intended to be traversed by an electric current, thereby generating a magnetic field in the respective leg.

[0027] In a further embodiment, the U-shaped, also horseshoe-shaped stator magnets of the respective stator magnet pairs are shaped in such a way that when one leg with a rotor magnet lies on top of each other, the other legs of the same stator magnet pair with further rotor magnets also lie on top of each other.

[0028] Each stator magnet is configured such that, when an electric current flows through its two coils, one leg of the respective stator magnet is configured as the north pole and the other leg as the south pole. As a result, a rotor magnet configured as the north pole is attracted to the leg configured as the south pole, and a rotor magnet configured as the south pole is attracted to the leg of the respective stator magnet configured as the north pole, such that the rotor is rotated about a first rotational axis coaxial with the central axis 8 of the rotor.

[0029] Furthermore, the coils of the stator magnets of the first stator magnet pair are connected to one another via a first electrical or electronic circuit and the coils of the stator magnets of the second stator magnet pair are connected to one another via a second electrical or electronic circuit.

[0030] It should be noted that the first and / or second electrical or electronic circuit can take on various embodiments. For example, such a circuit can be based on field-effect transistors, in particular MOSFET transistors, and can effect the function or logic defined by the present invention. Furthermore, the inventive function of the first and / or second electrical or electronic circuit can be achieved in various ways, for example, by a circuit comprising electrical resistors, transistors, and diodes. Furthermore, electrical coils and capacitors can be used.

[0031] The electric motor further comprises a first and a second Hall sensor. The first Hall sensor is arranged on the rotor such that when a rotor magnet of the rotor passes through the first Hall sensor, a first switching signal is provided, which causes the first electrical or electronic circuit to provide a first current flow through the coils of the first stator magnet pair.

[0032] The second Hall sensor is arranged on the rotor such that when the second Hall sensor is passed by a rotor magnet of the rotor, such a second switching signal is provided which causes the second electrical or electronic circuit to provide a second current flow through the coils of the second stator magnet pair.

[0033] By arranging two Hall sensors and thus doubling the switching signals provided compared to state-of-the-art electric motors with only one Hall sensor, faster switching between the first and second electrical or electronic circuits can be achieved. This faster switching enables a more consistent rotation of the rotor while simultaneously achieving higher speed / power.

[0034] In a further exemplary embodiment, the first and / or second current flow can be maintained until a next first and / or second switching signal is provided. This embodiment advantageously ensures that a current flows through the coils of a respective stator magnet pair until the power supply is switched off, thus permanently magnetizing one of the stator magnet pairs. In this way, certain rotor magnets (depending on their polarity and current position) are permanently attracted to the currently activated stator magnets of a stator magnet pair, thereby permanently exerting an acceleration force on the rotor. Thus, in addition to smooth rotation, high speeds, high torque, and high rotor power can be achieved.

[0035] In a further embodiment of the electric motor according to the invention, the first and second Hall sensors are arranged on the rotor such that a rotor magnet of the rotor passes through the first or second Hall sensors after a 30-degree rotation of the rotor. In certain embodiments, twelve evenly spaced switching signals are provided, particularly after a complete rotation of the rotor. This large number of evenly spaced switching signals can ensure a smooth, jerk-free rotation of the rotor of the electric motor. Furthermore, this makes the motor more powerful, and the rotor can achieve higher rotational speeds.

[0036] In a further embodiment of the electric motor according to the invention, the first and the second Hall sensor are arranged on the rotor in such a way that first and second switching signals are provided alternately.

[0037] Advantageously, the two Hall sensors can be arranged at various different positions on the rotor. However, in the respective embodiment, it is essential that the relative arrangement between the first Hall sensor and the second Hall sensor is designed such that the first and second Hall sensors are alternately passed by any rotor magnet after each rotation of the rotor by 30 degrees.

[0038] In a further embodiment of the electric motor according to the invention, the first electrical or electronic circuit can be configured such that, upon the application of a signal from the first Hall sensor, it provides a current flow through the coils of the first stator magnet pair and maintains this current flow until the rotor rotates by a certain number of degrees, in particular by 30 degrees. In certain embodiments, this current flow can be maintained by a transistor using a holding current provided by the first electrical or electronic circuit. This transistor can advantageously be a metal oxide semiconductor field-effect transistor (MOSFET).

[0039] In a further embodiment of the electric motor according to the invention, the stator can be configured to supply the coils of the first stator magnet pair with a first single-phase alternating current and to supply the coils of the second stator magnet pair with a second single-phase alternating current. The second single-phase alternating current can have a phase shift relative to the first single-phase alternating current. In a specific embodiment, the phase shift can be 90 degrees. Advantageously, the second single-phase alternating current can be provided by a phase shift of the first single-phase alternating current.

[0040] In certain embodiments, this phase shift can be achieved by connecting a capacitor and an inductor in parallel. Preferably, a starting capacitor can be connected in parallel with said capacitor, which can be switched on and off using an electrical or electronic switch and serves to start the motor.

[0041] Furthermore, it should be noted that the inventive arrangement of the rotor magnets and the stator magnets and the resulting magnetic forces between the rotor magnets and the stator magnets can contribute to centering the rotor. When a rotor magnet is opposite a stator magnet of the same polarity, a force is generated which acts in the direction of the central axis. If the distance between the two magnets is increased (e.g., increasing the air gap between rotor and stator), this force decreases. Conversely, if the air gap is reduced, the force increases. However, it should be noted that due to the inventive design, a rotor magnet on the opposite side of the rotor is also repelled by a stator magnet at the same time. This creates a further force whose effect is directed opposite to the opposing force.If the rotor were to move radially away from the center axis, thus increasing the air gap on one side, the repulsive force would decrease accordingly. However, the air gap between the rotor and the stator on the opposite side of the rotor would decrease accordingly, thus increasing the resulting force. This means that the resulting forces keep the rotor centered during rotation. When a rotor magnet is opposite a stator magnet of opposite polarity, the resulting forces counteract each other. This is also due to the fact that increasing or decreasing distances between the stator magnet and the rotor magnet lead to a decrease or increase in the forces, respectively, and thus, due to the symmetrical design, the resulting forces counteract each other.In other words, the rotor is radially supported by the magnetic forces between the rotor and the stator. Brief description of the drawings

[0042] The rotor and electric motor according to the invention are described in more detail below purely by way of example with reference to exemplary embodiments shown schematically in the figures. Identical elements are identified by the same reference numerals in the figures. The described embodiments are generally not drawn to scale and are not to be understood as limiting. In detail, Fig. 1A-1C: Perspective views of an exemplary embodiment of the rotor according to the invention, Fig. 2: Exemplary arrangement of an exemplary embodiment of the rotor according to the invention with two Hall sensors, Fig. 3A-3B: Exemplary embodiment of the electric motor according to the invention, Fig. 4: Schematic of an exemplary embodiment of the electrical or electronic circuit. Detailed description of the drawings

[0043] The Fig. 1A shows an exemplary embodiment of the rotor 1 according to the invention, which has six rotor magnets 2 that are precisely arranged in recesses. In the center of the rotor 1, a cavity 3 is visible, in which exemplary mechanical holding elements 4 are arranged. For example, a splined shaft connection (splined shaft-to-toothed hub toothing) could be formed in the cavity 3 as the mechanical holding element 4. However, other mechanical holding elements 4, such as a clamping connection, a pressure sleeve, a clamping element, a threaded pin, or the like, can also be used.

[0044] The six recesses 200, or the rotor magnets 2 arranged therein, are each radially offset by 60 degrees relative to the central axis or the rotation axis 8 of the rotor 1, respectively, in the outer surface 300, whereby there is an equal distance between two recesses 200 adjacent along the outer surface 300. The rotor magnets 2 are arranged such that they alternate along the outer surface 300 between rotor magnets 2 configured as north poles and rotor magnets 2 configured as south poles. These rotor magnets 2 configured as north poles and south poles, respectively, are described in particular from a viewpoint directed from outside the rotor 1, towards the rotor 1. In other words, the rotor magnets 2 are configured alternately as north poles and south poles towards the outside.

[0045] In certain embodiments, the recesses can each have a separating component 19, in particular a casting resin, also called potting resin. This separating component 19 is arranged between the respective recess 200 and the rotor magnet 2 arranged in the respective recess 200. In certain embodiments, this separating component 19 can also have an electrically insulating effect. The electrically insulating embodiment of the separating component 19 reduces the generation of eddy currents in the rotor 1.

[0046] The Fig. 1B shows the exemplary embodiment according to Fig. 1A, highlighting the arrangement of three magnetic flux transmission units 5, 6, 7. A first magnetic flux transmission unit 5 connects the first rotor magnet pair, a second magnetic flux transmission unit 6 connects the second rotor magnet pair, and a third magnetic flux transmission unit 7 connects the third rotor magnet pair. The three magnetic flux transmission units 5, 6, 7 could comprise a soft magnetic material. A magnetic flux transmission unit of this type is also called a soft iron bridge. The three magnetic flux transmission units 5, 6, 7 are axially offset from one another (along the central axis 8 of the rotor 1) so that they do not touch one another.

[0047] The Fig. Figure 1C shows a three-dimensional representation of the Fig. 1A. The rotor magnets 2, as well as the cavity 3, extend along the central axis 8 from the cover surface 400 of the rotor 1 over its entire length 10 to the base surface 500. The holding elements 4, which are designed as a toothed hub in the cavity 3, are intended to interact with the teeth (previously also called holding element counterparts) of a toothed shaft (previously also called rotation receiving unit) inserted into the cavity 3 of the rotor 1 and matched to the toothed hub in such a way that when the rotor 1 rotates about a first axis of rotation running coaxially to the central axis 8 of the rotor 1, the toothed shaft is also rotated about the first axis of rotation in a direction of rotation 11.

[0048] The Fig. Figure 2 shows an exemplary arrangement of the rotor 1 according to the invention with two Hall sensors. The two Hall sensors are arranged on the stator 110 such that they alternately generate a signal at intervals of 30 degrees when the rotor 1 rotates. It is noted that the Hall sensors 12, 13 could be arranged at various positions. Furthermore, it is noted that successive signals do not have to be triggered by the same rotor magnet 2. For example, the Hall sensors 12, 13 could be arranged offset by 90 degrees from one another. Thus, the first Hall sensor 12 would generate a signal as soon as it is passed by a first rotor magnet 2, and the second Hall sensor 13 would generate a next signal after the rotor rotates by 30 degrees.

[0049] In the exemplary embodiment shown in Fig. 3A shows a front view of the rotor 1 according to the invention (i.e., looking towards the cover surface 400 of the rotor 1), wherein three magnetic flux transmission units 5, 6, 7 are visible, which are arranged between two opposing recesses in such a way that, when two rotor magnets 2 arranged in the corresponding recesses 200 are exposed to a magnetic field provided by a stator 110 of the electric motor 100, a magnetic flux 20 between the rotor magnets 2 is provided or promoted.

[0050] The Hall sensors 12, 13 are attached to the rotor 1 in such a way that, when they are passed by a rotor magnet 2 of the rotor 1, a switching signal is alternately provided that causes the first or second electrical or electronic circuit 14, 21 to provide a first current flow through the respective stator magnet pairs.

[0051] It should be noted that the first and second electronic or electrical circuits 14, 21 may be the same, or their function may be provided by a single circuit. However, it should be noted that the signal and supply lines may still differ. In the exemplary embodiment of this figure, the first electrical or electronic circuit 14 and the second electrical or electronic circuit 21 are combined.

[0052] The exemplary electronic or electrical circuit 14, 21 supplies current to the coils of the stator magnets via lines V1+ and V1-, and V2+ and V2-, respectively. The Hall sensors are powered by a voltage supply, so their signals can be read via a signal line. For the sake of clarity, these three required connections of the Hall sensors 12, 13 are schematically shown in this figure (H1, H2) as individual lines with three connections each.

[0053] In certain embodiments, the Hall sensors 12, 13 can also be arranged such that the current supply to the coils 18 is interrupted before the rotor magnets 2 have reached the position of the stator magnets, or the current supply to the coils of the other stator magnet pair begins beforehand. A corresponding time offset can also be implemented in further embodiments using the electrical or electronic circuit 14, 21.

[0054] In Fig. 3B is based on the exemplary embodiment of Fig. 3A, a closed magnetic circuit is shown schematically between the stator magnets of a stator magnet pair. Two magnetic flux transmission units, which are arranged axially (in other words: in the axial direction along the central axis / rotational axis 8 of the rotor 1) offset from one another in the rotor 1, each magnetically connect two opposing rotor magnets 2 to one another. This promotes a magnetic flux 20 from the first stator magnet 15, via the corresponding adjacent rotor magnets 2 and via the magnetic flux transmission units 5 arranged therebetween, to the second stator magnet 15' of the stator magnet pair. The mutual attraction of the rotor magnets 2, which is promoted by the magnetic flux transmission units 5, 6, 7, additionally prevents any possible detachment of the rotor magnets 2, which can occur in the prior art, particularly at high speeds.

[0055] According to the state of the art, demagnetizing coils are often installed. These coils are attached to the stator magnets and serve to more quickly dissipate the residual magnetism of said stator magnets. Due to the high efficiency of the electric motor according to the invention, no additional coils and cables for demagnetizing the stator magnets—as is often the case in the state of the art—are required.

[0056] It should be noted that the electrical or electronic circuit 14, 21 of the electric motor according to the invention for electrical commutation is shown in the exemplary figures merely as a "black box." The required function can be achieved by various circuit embodiments. For example, the circuit can be implemented using MOSFET transistors. Fig.Figure 4 schematically illustrates a possible embodiment of an electrical or electronic circuit 14, 21. In this embodiment of the circuit, the output signals of the first (H1) and second (H2) Hall sensors are each fed to a MOSFET transistor (Q1; Q2), which closes the load current circuit. The voltage supply of the Hall sensors (V_Sensor+) differs from the supply voltage of the load current circuit (V_Load+), where V_Load+ in this embodiment corresponds to V1+ and V2+ of the previous figures. In the load current circuit, current flows through the coils of the stator magnets (L11-L14 for the first stator magnet pair and L21-L24 for the second stator magnet pair). Resistors R1 and R2 provide a holding current, which maintains said load current through a holding current generated by a holding voltage (H1+).The various circuits are closed via a common return line (GND, V1-, H1-). Switching off this holding current and the associated interruption of the load circuit can be achieved, for example, by removing the holding voltage. The point in time at which the load circuit should be interrupted varies in different embodiments. For example, an interruption is conceivable as soon as the attracted pole of the rotor has radially assumed the position of the attracting leg of the rotor magnet. In other embodiments, an interruption may also be possible immediately beforehand. Diodes D1 and D2 can enable more efficient demagnetization of the stator magnets.

[0057] It is understood that these figures only schematically depict possible embodiments. The various approaches can also be combined with each other and with prior art methods. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 202023101234 U1

[0006]

Claims

[1] Rotor (1) for an electric motor (100), wherein the rotor (1) is designed as a hollow body, in particular a hollow cylinder, the outer surface (300) of which runs around a central axis (8) of the rotor (1) and the hollow space (3) of which extends from a cover surface (400) to a base surface (500) along the central axis (8), and the lateral surface (300) of the rotor (1) has at least a first pair of recesses (200), wherein ◯ a first recess and a second recess of the first pair of recesses (200) are arranged opposite one another, and ◯ a first rotor magnet (2) designed as a north pole is arranged in the first recess of the first pair of recesses (200) and a second rotor magnet (2) designed as a south pole is arranged in the second recess of the first pair of recesses (200), characterized bythat between the first recess and the second recess of the first pair of recesses (200) a first magnetic flux transmission unit (5), in particular a first soft iron bridge, is arranged such that when the first rotor magnet (2) and / or the second rotor magnet (2) is exposed to a magnetic field provided by a stator (110) of the electric motor (100), a magnetic flux (20) is provided between the first rotor magnet (2) and the second rotor magnet (2). [2] Rotor (1) according to claim 1, wherein the outer surface (300) of the rotor (1) has a second and a third pair of recesses (200), whereby the rotor (1) has a total of six recesses (200), wherein the six recesses (200) are each radially offset by 60 degrees in the outer surface (300) relative to the central axis (8) of the rotor (1), whereby there is an equal distance between each two recesses (200) adjacent along the outer surface (300). [3] Rotor (1) according to claim 2, wherein in the second pair of recesses (200) a third rotor magnet (2) designed as a north pole and a fourth rotor magnet (2) designed as a south pole and in the third pair of recesses (200) a fifth rotor magnet (2) designed as a north pole and a sixth rotor magnet (2) designed as a south pole are arranged such that rotor magnets (2) designed as a north pole and those designed as a south pole alternate along the lateral surface (300). [4] Rotor (1) according to one of the preceding claims, wherein the rotor (1) has a second and a third magnetic flux transmission unit (6, 7), in particular a second and a third soft iron bridge, the second magnetic flux transmission unit (6) is arranged between the recesses of the second pair of recesses (200) and the third magnetic flux transmission unit (7) is arranged between the recesses of the third pair of recesses (200), and the first, second and third magnetic flux transmission units (5,6,7) are arranged offset from one another in the axial direction of the central axis (8) of the rotor (1). [5] Rotor (1) according to one of the preceding claims, wherein the respective recess (200) of a respective pair of recesses has a separating component (19), in particular a casting resin, wherein the separating component (19) is arranged between the respective recess (200) and the rotor magnet (2) arranged in the respective recess (200), in particular wherein the separating component (19) has an electrically insulating effect. [6] Rotor (1) according to one of the preceding claims, wherein mechanical holding elements (4) are arranged within the cavity (3), which are provided to cooperate with matching holding element counterparts of a rotation receiving unit inserted into the cavity (3) of the rotor (1) in such a way that when the rotor (1) rotates about a first rotation axis running coaxially to the central axis (8) of the rotor (1), the rotation receiving unit is also rotated about the first rotation axis. [7] Rotor (1) according to claim 6, wherein the respective magnetic flux transmission unit (5, 6, 7) comprises the mechanical holding elements (4). [8] Rotor (1) according to claim 6 or 7, wherein the mechanical holding elements (4) form a toothed hub, wherein the toothed hub is designed to cooperate with a rotation receiving unit designed as a toothed shaft. [9] Rotor (1) according to one of the preceding claims, wherein a respective rotor magnet (2) arranged in a respective recess • the compound contains iron oxide, in particular consists of iron oxide, and / or • has at least one rare earth metal, in particular consists of at least one rare earth metal. [10] Electric motor (100) comprising a rotor (1) according to one of claims 1 to 9 and a stator (110), wherein • the stator (110) has a first and a second stator magnet pair, wherein ◯ the stator magnets of the first stator magnet pair (15, 15') are arranged opposite one another on the rotor (1), and o the stator magnets of the second stator magnet pair (16, 16') are arranged opposite each other on the rotor (1) and offset by 90 degrees from the first stator magnet pair (15, 15'), • the respective stator magnets (15, 15', 16, 16') are U-shaped, • one leg (17) of a respective U-shaped stator magnet (15, 15', 16, 16') ◯ is formed onto the rotor (1), and ◯ a coil (18) intended to be traversed by an electric current and thereby to generate a magnetic field in the respective leg (17), • a respective stator magnet (15, 15', 16, 16') is designed such that when an electric current flows through the two coils (18) of the respective stator magnet (15, 15', 16, 16'), one leg (17) of the respective stator magnet (15, 15', 16, 16') is designed as a north pole and the other leg (17) as a south pole, whereby a rotor magnet (2) designed as a north pole is attracted by the leg (17) designed as a south pole and a rotor magnet (2) designed as a south pole is attracted by the leg (17) of the respective stator magnet (15, 15', 16, 16') designed as a north pole in such a way that the rotor (1) is rotated about a first axis of rotation running coaxially to the central axis (8) of the rotor (1), • the coils (18) of the stator magnets of the first stator magnet pair (15, 15') are connected to one another via a first electrical or electronic circuit (14), and • the coils of the stator magnets of the second stator magnet pair (16, 16') are connected to one another via a second electrical or electronic circuit (21). [11] Electric motor (100) according to claim 10, wherein the electric motor (100) further comprises a first and a second Hall sensor (12, 13), wherein the first and the second Hall sensor (12, 13) are arranged on the rotor (1) such that when • the first Hall sensor (12) is passed by a rotor magnet of the rotor (1), such a first switching signal is provided, which causes the first electrical or electronic circuit (14) to provide a current flow through the coils (18) of the first stator magnet pair (15, 15'), and • the second Hall sensor (13) is passed by a rotor magnet of the rotor (1), such a second switching signal is provided which causes the second electrical or electronic circuit (21) to provide a current flow through the coils (18) of the second stator magnet pair (16, 16'). [12] Electric motor (100) according to claim 11, wherein the electric motor (100) has a rotor (1) according to claim 3, wherein the first and the second Hall sensor (12, 13) are arranged on the rotor (1) in such a way that the first or the second Hall sensor (12, 13) is passed by a rotor magnet (2) of the rotor (1) after a rotation of the rotor (1) by 30 degrees, in particular wherein after a complete rotation of the rotor (1) twelve evenly offset switching signals are provided. [13] Electric motor (100) according to claim 12, wherein the first and second Hall sensors (12, 13) are arranged on the rotor (1) such that first and second switching signals are provided alternately. [14] Electric motor (100) according to one of claims 10 to 13, wherein the first electrical or electronic circuit (14) is configured such that, after the application of a signal from the first Hall sensor (12), it provides a current flow through the coils (18) of the first stator magnet pair (15, 15') and maintains this current flow until the rotor (1) rotates by a certain number of degrees, in particular wherein this current flow is maintained by a transistor, in particular a metal oxide semiconductor field effect transistor (MOSFET), by means of a holding current provided by the first electrical or electronic circuit (14). [15] Electric motor (100) according to claim 10, wherein the stator (110) is designed to supply the coils (18) of the first stator magnet pair (15, 15') with a first single-phase alternating current and to supply the coils (18) of the second stator magnet pair (16, 16') with a second single-phase alternating current, wherein the second single-phase alternating current has a phase shift compared to the first single-phase alternating current, in particular a phase shift of 90 degrees, in particular wherein the second single-phase alternating current is provided by a phase shift of the first single-phase alternating current.

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