EP4162588A1

EP4162588A1 - Electric motor and method for operating an electric motor

Info

Publication number: EP4162588A1
Application number: EP21732849.1A
Authority: EP
Inventors: Maurice ANDREE; Stefan TILLER; Hong Giang TO
Original assignee: GKN Powder Metallurgy Engineering GmbH
Current assignee: GKN Powder Metallurgy Engineering GmbH
Priority date: 2020-06-09
Filing date: 2021-06-09
Publication date: 2023-04-12
Also published as: US20230223828A1; BR112022025152A2; CN116034532A; DE102020115263B4; WO2021250108A1; JP2023528980A; DE102020115263A1

Abstract

The invention relates to an electric motor (1), comprising at least a stator (2), which extends between a first end face (3) and a second end face (4) along an axial direction (5) and has an annular yoke (6) on the first end face (3) and starting from the yoke (6) a plurality of cores (7), which each extend along the axial direction (5) over a first length (8) to the second end face (4) and are arranged adjacent to one another along a circumferential direction (9), wherein a coil (10) is arranged on each core (7), which coil extends starting from the yoke (6) along the axial direction (5) over a second length (11) toward the second end face (4), wherein the second length (11) is shorter than the first length (8), so that a portion (12) of each core (7) extends along the axial direction (5) beyond the coil (10) concerned; wherein the motor (1) additionally comprises at least one first rotor (13) which is arranged, at least on the second end face (4) along the axial direction (5) between the coils (10) and the second end face (4).

Description

Electric motor and method of operating an electric motor

The present invention relates to an electric motor, the electric motor comprising at least one stator and one rotor.

There is a constant need to reduce the size of electric motors or to expand their functionality.

Proceeding from this, it is the object of the present invention to propose an electric motor which can implement these aspects. In particular, an electric motor is to be specified in which two rotors can be operated independently of one another via a single stator. With regard to this application, an advantageous design of an electric motor is to be provided.

To achieve these objects, an electric motor according to the features of claim 1, a first method for operating an electric motor according to claim 9 and a second method for operating an electric motor according to claim 10 are proposed. Advantageous further developments are the subject of the dependent claims. The features listed individually in the patent claims can be combined with one another in a technologically meaningful manner and can be supplemented by explanatory facts from the description and details from the figures, with further design variants of the invention being shown.

Contributing to this is an electric motor, which has at least one stator which extends between a first end face and a second end face along an axial direction and has an annular yoke on the first end face and, starting from the yoke, a plurality of cores, each of which is arranged extend along the axial direction over a first length to the second end face and are arranged next to one another along a circumferential direction. A coil is arranged on each core and extends, starting from the yoke, along the axial direction over a second length towards the second end face. The second length is less than the first length so that a portion of each core extends across the respective coil along the axial direction. The motor additionally has at least one first rotor which is arranged at least on the second end face along the axial direction between the coils and the second end face, the first rotor (essentially) being a first component oriented along a radial direction during operation of the motor uses the magnetic flux generated by the stator to drive the first rotor.

In particular, a stator which is constructed according to a type of axial flux motor is combined with a first rotor which is constructed and arranged according to a type of radial flux motor.

In an axial flux motor, the stator and rotor are arranged next to one another along the axial direction, the rotor having poles which are opposite the coils or cores along the axial direction and possibly aligned at least along the axial direction (e.g. on the same diameter ) are arranged. The stator has cores and coils which, starting from an annular base body (yoke), extend along the axial direction. The number of coils or cores and the number of poles of the rotor can differ from one another or correspond to one another.

In an axial flux motor, a second component, aligned along the axial direction, of the magnetic flux generated by the stator is used to drive the rotor.

In a radial flux motor, the stator and rotor are arranged next to one another along the radial direction, the rotor having poles that are opposite the coils or cores along the radial direction and possibly aligned at least along the radial direction (e.g. on the same section un- long the axial direction) are arranged. In the stator, stator teeth or cores extend inward or outward in the radial direction, starting from an annular base body (yoke).

In a radial flux motor, a first component, aligned along the radial direction, of the magnetic flux generated by the stator is used to drive the rotor.

The stator of the electric motor has in particular a soft magnetic material, for example a so-called “soft magnetic composite” (SMC), or a combination of electrical steel sheets and SMC. The cores of the stator are preferably made of a soft magnetic material pressed and baked. The SMC material is not sintered here. Rather, the temperature is controlled to below a melting temperature, which, however, is sufficient for the cores to retain their geometry over the long term.

The respective rotor has, in particular, permanent magnets and / or soft magnetic elements, for example in cutouts. A permanent magnet synchronous or brushless direct current motor, abbreviated BLDC, can preferably be formed with permanent magnets, while a reluctance motor can be created as an electric motor with soft magnetic elements, for example.

The respective rotor can alternatively be designed as a squirrel cage or squirrel cage rotor or as a slip ring rotor, in which case an asynchronous machine is designed.

In particular, the rotor is at least partially produced by sintering. In particular, complex structures can be formed on the rotor in a very simple manner in terms of sintering. The structure of a stator, in particular using SMC, and further details, also relating to a rotor, can be found, for example, in WO 2016/066714 A1.

In particular, during operation of the motor, a drive force acting between the stator and the first rotor can be generated in a region of the first rotor which is arranged in the radial direction at least inside or outside the cores.

In particular, the first rotor is designed so that the area, so z. B. the poles of the rotor, are arranged in the radial direction only inside or only outside of the cores.

Alternatively, the first rotor is designed in such a way that two areas are provided, that is to say one in the radial direction inside and one outside the cores. In this embodiment, the two areas are mechanically coupled to one another, the number of poles present in the respective area being the same. This makes it possible to provide an electric motor with which, on the one hand, a high torque can be achieved and in which only a small resultant force acting in the axial direction is generated compared to the use of a rotor which is constructed according to a type of axial flux motor.

The motor preferably comprises at least the first rotor and a second rotor, the region of the one rotor being arranged outside the cores in the radial direction and the region of the other rotor being arranged in the radial direction inside the cores. In the case of the motor, in particular at least two rotors can be operated independently of one another via a single stator.

For this design with two rotors, there are particularly advantageous operating modes that are explained below. In particular, the motor additionally comprises a rotor component which forms a third rotor or a part of the first rotor or a second rotor. The rotor component is arranged adjacent to the stator along the axial direction. When the motor is in operation, the rotor component uses a second component, aligned along the axial direction, of the magnetic flux generated by the stator to drive the rotor component.

In particular, this rotor component is constructed according to a type of axial flux motor. In an axial flux motor, the stator and rotor component are arranged next to one another along the axial direction, the rotor component having poles that are opposite the coils or cores of the stator along the axial direction and possibly in alignment at least along the axial direction (e.g. on a same diameter) are arranged.

The rotor component can form an independent third rotor, so that the motor has the first rotor and the third rotor or additionally the second rotor. The third rotor can also be designed to be mechanically coupled to the first rotor or, if present, to the second rotor. In the case of a mechanical coupling, the relevant rotors, or the relevant rotor and the rotor component, have the same number of poles.

In particular, the motor comprises at least two rotors, the rotors having a different number of poles from one another, so that the rotors can be operated at least at a different speed or with a different direction of rotation. Each rotor is driven directly by the rotating field of the stator. A gear or a translation is not required here.

If the motor is designed as a synchronous motor, the rotating field generated by the stator must be provided in a fixed relationship to the respective position of the rotor in question. The rotating field can in particular be provided as a compromise depending on the position of each rotor or only depending on depending on the position of a rotor. In the latter case, the at least one other rotor must then follow this rotating field.

In particular, z. B. one rotor can be operated via the rotating field of the stator at twice as high a speed as the other rotor, possibly with the opposite direction of rotation. The proposed motor, which has only one stator but at least two rotors, could thus replace two known motors in which only one rotor can ever be operated via a stator.

In particular, the motor comprises at least two rotors, at least one rotor having a first design for a synchronous machine and at least the other rotor having a second design for an asynchronous machine, with a rotating field of the stator being aligned with the rotor of the first design during operation of the motor and the rotor of the second design follows the rotating field with a slip. Regulation of the rotating field can thus be simplified, since the rotor of the second design passively follows the rotating field.

In particular, the motor comprises at least two rotors, the rotors having different starting torques, so that one rotor can be operated at one speed while the other rotor is stationary. In particular, one rotor can be operated to control the temperature of the other rotor.

In particular, the motor comprises at least two rotors, one rotor having a fluid delivery geometry for delivering a fluid, the delivery of the fluid being provided for temperature control of the other rotor. In particular, the fluid delivery geometry is designed in the manner of a pump, so that the rotation of the rotor causes a fluid to move in a specific, in particular constant, direction.

A (first) method for operating an electric motor, in particular the motor described, is also proposed. The engine has a Stator and at least two rotors, the one rotor having a first number of poles and the other rotor having a second number of poles, the rotors being operated at least at a different speed or with a different direction of rotation. In the case of the motor, in particular at least two rotors can be operated independently of one another via a single stator.

Each rotor is driven directly by the rotating field of the stator. A gear or a translation is not required here.

A (second) method for operating an electric motor, in particular the motor described, is proposed. The motor has a stator and at least two rotors, the rotors having different starting torques, so that one rotor is operated at one speed while the other rotor is stationary. In the case of the motor, in particular at least two rotors can be operated independently of one another via a single stator.

The statements relating to the motor apply in particular equally to the methods described and vice versa.

The use of indefinite articles (“a”, “an”, “an” and “an”), especially in the patent claims and the description reproducing them, is to be understood as such and not as a numerical word. The terms or components introduced in this way are therefore to be understood in such a way that they are present at least once and, in particular, can also be present several times.

As a precaution, it should be noted that the numerals used here (“first”, “second”, “third”, ...) primarily (only) serve to differentiate between several similar objects, sizes or processes, i.e. in particular no dependency and / or sequence these objects, sizes or processes are mandatory for each other. Should a dependency and / or sequence be required be the case, this is explicitly stated here or it is obvious to a person skilled in the art when studying the specifically described embodiment.

The invention and the technical environment are explained in more detail below with reference to the figures. It should be pointed out that the invention is not intended to be restricted by the exemplary embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and to combine them with other components and findings from the present description and / or figures. The same reference symbols denote the same objects, so that explanations from other figures can be used in addition, if necessary. They show schematically:

1: a first embodiment variant of an electric motor in a perspective view;

FIG. 2: the electric motor according to FIG. 1 in a perspective view; FIG.

3: the electric motor according to FIGS. 1 and 2 in a side view;

4: a second embodiment variant of an electric motor in a perspective view;

5: a third embodiment variant of an electric motor in a perspective view; and

6: a fourth variant embodiment of an electric motor in a side view. 1 shows a first embodiment variant of an electric motor 1 in a perspective view. FIG. 2 shows the electric motor 1 according to FIG. 1 in a perspective view. Fig. 3 shows the electric motor 1 according to FIGS. 1 and 2 in a side view. FIGS. 1 to 3 are described jointly below.

The electric motor 1 has a stator 2, which extends between a first end face 3 and a second end face 4 along an axial direction 5 and has an annular yoke 6 on the first end face 3 and a plurality of cores 7 starting from the yoke 5 which each extend along the axial direction 5 over a first length 8 to the second end face 4 and are arranged next to one another along a circumferential direction 9. Arranged on each core 7 is a coil 10 which, starting from the yoke 6, extends along the axial direction 5 over a second length 11 to the second end face 4. The second length 11 is smaller than the first length 8, so that a section 12 of each core 7 extends along the axial direction 5 over the respective coil 10. The motor 1 additionally has a first rotor 13 and a second rotor 19, which are arranged on the second end face 4 and in each case along the axial direction 5 between the coils 10 and the second end face 4. During operation of the motor 1, the first rotor 13 and the second rotor 19 use (essentially) a first component 15, which is aligned along a radial direction 14, of the magnetic flux 16 generated by the stator 2 for driving purposes.

A stator 2, which is constructed according to a type of axial flux motor, is combined with a first rotor 13 and a second rotor 19, which are each constructed and arranged according to a type of radial flux motor.

In an axial flux motor, the stator 2 and third rotor 21 (see FIGS. 5 and 6) are arranged next to one another along the axial direction 5, the rotor 21 having poles 26 which lie opposite and along the coils 10 or cores 7 along the axial direction 5 the axial direction 5 are arranged in alignment (on the same diameter). In the case of an axial flux motor, a second component 22, aligned along the axial direction 5, of the magnetic flux 16 generated by the stator 2 is used to drive the rotor 21.

In a radial flux motor, the stator 2 and rotor 13, 19 are arranged next to one another along the radial direction 14, the rotor 13, 19 having poles 26 which lie opposite the coils 10 or cores 7 along the radial direction 14 and possibly at least along the radial direction Direction 14 are aligned (on the same section 12 along the axial direction 5).

In the case of a radial flux motor, a first component 15, aligned along the radial direction 14, of the magnetic flux 16 generated by the stator 2 is used to drive the rotor 13, 19.

During operation of the motor 1, a drive force 17 acting between the stator 2 and the first rotor 13 as well as the second rotor 19 can be generated in an area 18 of the first rotor 13 and in an area 18 of the second rotor 19, each in the radial direction 14 inside (second rotor 19) or outside (first rotor 13) of the cores 7 is arranged.

The first rotor 13 and the second rotor 19 are each designed in such a way that the region 18 and the poles 26 of the rotor 13, 19, in the radial direction 14, are each arranged only inside or only outside of the cores 7.

The motor 1 comprises the first rotor 13 and the second rotor 19, the region 18 of the first rotor 13 being arranged outside the cores 7 in the radial direction 14 and the region 18 of the second rotor 19 being arranged inside the cores 7 in the radial direction 14 .

Here the rotors 13, 19 have the same number of poles, ie each rotor 13, 19 has twelve poles 26. 4 shows a second embodiment variant of an electric motor 1 in a perspective view. Reference is made to the statements relating to FIGS. 1 to 3.

In contrast to the first variant, the electric motor 1 according to the second variant has only one rotor, namely a second rotor 19, the region 18 of the second rotor 19 being arranged in the radial direction 14 within the cores 7.

The second rotor 19 has a fluid delivery geometry 23 for delivering a fluid, wherein the delivery of the fluid for temperature control z. B. another rotor can be provided. The fluid delivery geometry 23 is designed in the manner of a pump, so that the rotation of the second rotor 19 causes a fluid to move in a specific direction, here essentially the axial direction 5.

The second rotor 19 is arranged on a first shaft 24.

5 shows a third variant embodiment of an electric motor 1 in a perspective view. Reference is made to the statements relating to FIG. 2.

In contrast to the second embodiment variant, the motor 1 according to the third embodiment variant has two rotors, namely a third rotor 21 in addition to the second rotor 19, the region 18 of which is arranged in the radial direction 14 within the cores 7.

The motor 1 according to the third embodiment variant comprises a rotor component 20 which forms the third rotor 21. The rotor component 20 is arranged next to the stator 2 along the axial direction 5. When the motor 1 is in operation, the rotor component 20 uses a second component 22, which is aligned along the axial direction 5, of the magnetic flux 16 generated by the stator 2 to drive the rotor component 20. This rotor component 20 is constructed according to a type of axial flux motor. In an axial flux motor, the stator 2 and rotor component 20 are arranged next to one another along the axial direction 5, the rotor component 20 having poles 26 which are opposite the coils 10 or cores 7 of the stator 2 along the axial direction 5 and possibly at least along the axial direction 5 are arranged in alignment (e.g. on the same diameter).

The rotor component 20 forms an independent third rotor 21, so that the motor 1 has the second rotor 19 and the third rotor 21.

The second rotor 19 comprises the fluid delivery geometry 23 for delivering a fluid, the delivery of the fluid being provided for temperature control of the third rotor 21.

6 shows a fourth variant embodiment of an electric motor 1 in a side view. Reference is made to the statements relating to FIGS. 1 to 5.

The motor 1 comprises the first rotor 13 and the second rotor 19, the region 18 of the first rotor 13 being arranged outside the cores 7 in the radial direction 14 and the region 18 of the second rotor 19 being arranged inside the cores 7 in the radial direction 14 . The first rotor 13 is connected to the first shaft 24 in a rotationally fixed manner.

The motor 1 additionally comprises a rotor component 20 which forms part of the second rotor 19. The rotor component 20 is arranged next to the stator 2 along the axial direction 5. When the motor 1 is in operation, the rotor component 20 uses a second component 22, which is aligned along the axial direction 5, of the magnetic flux 16 generated by the stator 2 to drive the rotor component 20. The second rotor 19 and the rotor component 20 are coupled to one another and are non-rotatably connected to the second shaft 25 via the rotor component 20.

List of reference symbols

I motor 2 stator

3 first face

4 second face

5 axial direction

6 yoke 7 core

8 first length

9 circumferential direction

10 coil

I I second length 12 section

13 first rotor

14 radial direction

15 first component

16 magnetic flux 17 driving force

18 area

19 second rotor

20 rotor component

21 third rotor 22 second component

23 Fluid delivery geometry

24 first wave

25 second wave

26 pol

Claims

Electric motor (1), at least having a stator

(2), which is located between a first end face

(3) and a second face

(4) extends along an axial direction (5) and has an annular yoke (6) on the first end face (3) and, starting from the yoke (6), a plurality of cores (7) which each extend along the axial direction

(5) extend over a first length (8) to the second end face (4) and are arranged next to one another along a circumferential direction (9), a coil (10) being arranged on each core (7), which extends from the yoke

(6) extends along the axial direction (5) over a second length (11) towards the second end face (4), the second length (11) being smaller than the first length (8), so that a section (12) each core (7) extends along the axial direction (5) over the respective coil (10); wherein the motor (1) additionally comprises at least one first rotor (13) which is arranged at least on the second end face (4) along the axial direction (5) between the coils (10) and the second end face (4), the The first rotor (13) uses a first component (15), which is aligned along a radial direction (14), of the magnetic flux (16) generated by the stator (2) for driving purposes when the motor (1) is in operation.

Motor (1) according to claim 1, wherein during operation of the motor (1) a drive force (17) acting between the stator (2) and the first rotor (13) can be generated in a region (18) of the first rotor (13), which is arranged in the radial direction (14) at least inside or outside the cores (7).

Motor (1) according to claim 2, at least comprising the first rotor (13) and a second rotor (19), wherein the region (18) of the one rotor (13, 19) in the radial direction (14) outside of the cores (7 ) and the rich (18) of the other rotor (19, 13) in the radial direction (14) inside the cores

(7) is arranged.

Motor (1) according to one of the preceding claims, additionally comprising a rotor component (20) which forms a third rotor (21) or a part of the first rotor (13) or a second rotor (19), the rotor component (20) along the axial direction (5) is arranged next to the stator (2), wherein the rotor component (20) during operation of the motor (1) is aligned along the axial direction (5) second component (22) of the generated by the stator (2) uses magnetic flux (16) to drive.

Motor (1) according to one of the preceding claims 3 and 4, comprising at least two rotors (13, 19, 21), the rotors (13, 19, 21) having a different number of poles, so that the rotors (13, 19, 21) can be operated at least at a different speed or with a different direction of rotation.

Motor (1) according to one of the preceding claims 3 to 5, comprising at least two rotors (13, 19, 21), at least one rotor (13, 19, 21) having a first design for a synchronous machine and at least the other rotor (21 , 19, 13) has a second design for an asynchronous machine, with a rotating field of the stator (2) being aligned with the rotor (13, 19, 21) of the first design during operation of the motor (1) and the rotor (21, 19 , 13) of the second design follows the rotating field with a slip.

Motor (1) according to one of the preceding claims 3 to 6, comprising at least two rotors (13, 19, 21), the rotors (13, 19, 21) having different starting torques, so that the one rotor (13, 19, 21 ) can be operated at one speed while the other rotor (21, 19, 13) is stationary.

8. Motor (1) according to one of the preceding claims 3 to 7, comprising at least two rotors (13, 19, 21), wherein the one rotor (13, 19, 21) has a fluid delivery geometry (23) for delivering a fluid, where - when conveying the fluid to control the temperature of the other rotor (21,

19, 13) is provided.

9. A method for operating an electric motor (1), the motor (1) having a stator (2) and at least two rotors (13, 19, 21), the one rotor (13, 19, 21) having a first number of poles and the other rotor (21,

19, 13) has a second number of poles, the rotors (13, 19, 21) being operated at least at a different speed or with a different direction of rotation.

10. A method for operating an electric motor (1), the motor (1) having a stator (2) and at least two rotors (13, 19, 21), the rotors (13, 19, 21) having different starting torques, so that one rotor (13, 19, 21) is operated at one speed while the other rotor (21, 19, 13) is stationary.