WO2020239850A1

WO2020239850A1 - Electric machine, method for operating an electric machine, and wheel rim for an electrically operated motor vehicle

Info

Publication number: WO2020239850A1
Application number: PCT/EP2020/064727
Authority: WO
Inventors: Majd Jbeili
Original assignee: HELDER, Michael
Priority date: 2019-05-29
Filing date: 2020-05-27
Publication date: 2020-12-03

Abstract

The invention relates to an electric machine (1-1f), in particular an electric drive (1- 1f), which has at least one stator (2-2f) comprising magnetic or magnetisable stator elements (5-7; 5a-7a; 24-26, 30-32; 5c-7c; 5d-7d; 5e-7e; 5f-7f) and at least one rotor (8-8f) comprising magnetic or magnetisable rotor elements (10-12; 10a-12a; 10b-12b; 10c-12c; 10d-12d; 10e-12e; 10f-12f). It is advantageous for at least one of the stator elements (5-7; 5a-7a; 24-26, 30-32; 5c-7c; 5d-7d; 5e-7e; 5f-7f) and at least one of the rotor elements (10-12; 10a-12a; 10b-12b; 10c-12c; 10d-12d; 10e-12e; 10f-12f) to be spaced apart from one another in the axial direction of an axis of rotation (3-3f) of the electrical machine (1-1f). This arrangement makes it possible to replace the rotor or the stator easily. Both the stator and the rotor are accessible. An electric machine according to the invention is advantageous and particularly easy to maintain. The invention also relates to a method for operating an electric machine and to a wheel rim for an electrically operated motor vehicle.

Description

Description:

Majd Jbeili, 66115 Saarbrücken; Michael Helder, 66113 Saarbrücken (Germany) "Electrical machine, method for operating an electrical machine and rim for an electrically operated motor vehicle"

The invention relates to an electrical machine, in particular an electrical drive, which has at least one stator with magnetic or magnetizable stator elements and at least one rotor with magnetic or magnetizable rotor elements. The invention also relates to a method for operating an electrical machine and a rim for an electrically operated motor vehicle.

Electrical machines, in particular electric motors, are known from the prior art, in which a hollow cylindrical stator surrounds a rotor and an annular gap is formed between the stator and rotor. The disadvantage of this design is that the

Electric motor must be completely disassembled for maintenance or repair.

The present invention is based on the object of designing an electrical machine of the type mentioned at the beginning, which is particularly simple in construction. The invention is also based on the object of developing a method for operating an electrical machine with which a particularly high torque can be provided.

According to the invention, the object is achieved in that at least one of the stator elements and at least one of the rotor elements are arranged at a distance from one another in the axial direction of an axis of rotation of the electrical machine.

This non-nested arrangement makes it easy to replace the rotor or stator. Both the stator and the rotor are accessible. A

The electrical machine according to the invention is advantageously particularly easy to maintain.

If several stators and / or rotors are provided, which are arranged alternately in the axial direction of the axis of rotation of the electrical machine, a particularly compact machine is created. Furthermore, this cascade-like arrangement creates an electrical machine that can generate a particularly high torque. The rotor can be designed as the rim of a motor vehicle, and the stator can be part of a steering knuckle or the axle of the motor vehicle.

A perforated disk-shaped gap is expediently formed between the rotor and the stator. The gap is preferably designed as an air gap. Because the gap is in the shape of a perforated disk, it has a particularly large surface which is delimited by the rotor and the stator. If air flows through the perforated disk-shaped gap, particularly good cooling of the stator and / or the rotor is advantageously achieved. A flow occurs during the operation of the electrical machine due to the rotation of the rotor.

In one embodiment of the invention, the at least one rotor and / or the at least one stator is / are designed in the form of a disk. A circular training is particularly advantageous. The axis of rotation of the electrical machine is perpendicular to a disk plane and runs through the center of gravity or the center of the disk. Advantageously, no transverse forces loading a bearing occur.

It is conceivable that the disk planes of the stator and rotor are arranged in parallel and / or at an angle or perpendicular to the axis of rotation of the electrical machine.

In a further embodiment of the invention, several rotor and / or several stator arms are provided on which the stator and / or rotor elements are arranged and which preferably extend away from the axis of rotation with a radial directional component. Although it is conceivable to form a, for example, disk-shaped stator and / or a, for example, disk-shaped rotor from a solid material, retaining arms are provided for stator or rotor elements which extend away from the axis of rotation of the machine. A particularly light machine is advantageously created, the rotor of which in particular has a low mass moment of inertia. The stator and / or rotor arms can be formed from a metallic or non-metallic material, from plastic or from a fiber composite material.

Although the stator or rotor arms are preferably rod-shaped, other configurations are conceivable, for example a frustoconical configuration.

It is conceivable that the stator or rotor arms are curved, sinusoidal or cosinusoidal. In particular, the stator arms can, for example, be rod-shaped

formed and curved sinusoidally and the rotor arms rod-shaped and curved cosine-shaped. If the rotor is designed as the rim of an electrically operated motor vehicle, at least some of the rim spokes can be designed as rotor arms.

It is conceivable that the stator or rotor arms have stator arm sections or rotor arm sections in which the arms are magnetically designed or magnetizable,

are formed for example from copper or have copper, while other areas are formed from aluminum, a plastic or fiber composite material.

The stator arms are preferably of the same length and the rotor arms are of the same length. The rotor arms can be just as long, shorter or longer than the stator arms.

Because the stator or rotor arms are the same length, there is a distance from the

The ends of the rotor or stator arms facing away from the axis of rotation to the axis of rotation of the electrical machine are the same for each stator or rotor arm. A disk-shaped design is possible. Such a machine has no imbalance.

In one embodiment of the invention, several rotor and / or several stator arms are provided on which the stator and / or the rotor elements are attached, the rotor and / or the stator arms in a disk plane of the at least one rotor and / or the at least a stator are arranged. Adjacent rotor and / or stator arms preferably extend away from the axis of rotation of the electrical machine with a radial directional component.

Adjacent rotor or stator arms can be connected to one another at the ends facing away from the axis of rotation of the electrical machine or can have free ends. If they are connected to one another at the ends facing away from the axis of rotation, the stiffness of the rotor in particular is increased, and deformation of the rotor arms due to bending forces during operation is advantageously prevented.

A number of rotor arms of the at least one rotor is expediently different from a number of stator arms of the at least one stator.

So-called freezing of the machine is advantageously prevented. Magnetic forces causing a rotation of the rotor can always act between the stator and rotor elements. If eight arms are provided, one angle is that of adjacent arms

is included, for example 45 degrees, while an angle with seven arms is 51.43 degrees.

It is conceivable that an electrical machine according to the invention has very many more stator arms than rotor arms, in particular between two and twenty times as many stator arms like rotor arms. For example, 60 stator arms and 8 rotor arms can be provided. It is advantageously ensured that a distance between two adjacent stator arms is so small that particularly large magnetic forces can act on a rotor arm moved between these two stator arms during machine operation. A particularly smooth-running machine is also advantageously created.

It is also conceivable that the stator and rotor arms are not arranged equidistantly in the circumferential direction, that is, that angles enclosed by pairs of adjacent stator or rotor arms are different from one another. This irregular arrangement of the stator or rotor arms only acts on a single rotor arm magnetic forces to generate a torque. Bearing forces are reduced. A low-wear electrical machine is advantageously designed.

Although it is conceivable that each stator arm of the at least one stator has a single stator element and each rotor arm of the at least one rotor has a single rotor element, in one embodiment of the invention each stator arm of the at least one stator has a plurality of stator elements that are spaced apart from one another along the stator arm and / or each rotor arm of the at least one rotor has a plurality of rotor elements which are arranged at a distance from one another along the rotor arms. Rotor or stator elements can, for example, be coils,

Be permanent magnets or electro-permanent magnets, one area wise

Cause magnetization or magnetic formation of the stator or rotor arms. A certain number of stator or rotor elements can be used to tailor a torque required for the operation of the machine. The higher the number of elements, the greater the torque that can be achieved.

Preferably, the rotor elements are designed as permanent magnets and the

Stator elements as coils.

If the electrical machine is designed as a reluctance motor, the rotor elements are made of a highly permeable, soft magnetic material, for example an iron-silicon alloy.

It is conceivable that a plurality of rotor or stator elements are arranged in a central area of the stator and / or rotor arms, while a smaller number of stator or rotor elements is arranged in an inner area facing an axis of rotation or an outer area facing away from an axis of rotation . For example, in the inner and outer areas each have an element, while in the

Central area five elements are arranged.

It is also conceivable that the stator and / or rotor elements preferably

are arranged exclusively in a central area of the stator or rotor arms. A particularly smooth-running electrical machine is advantageously designed with which a particularly high torque can be generated.

Although it is conceivable that the diameter of the at least one stator is larger than the diameter of the at least one rotor, the diameter of the at least one rotor is expediently larger than the diameter of the at least one stator. Edge effects that reduce the efficiency of the electrical machine, in particular in regions of the stator or rotor facing away from the axis of rotation, are advantageously reduced.

In a further embodiment of the invention, the stator elements enclose one

Stator arm of the at least one stator at least partially in the circumferential direction or are attached to at least one side surface of a stator arm and / or the rotor elements of the at least one rotor at least partially enclose a rotor arm in the circumferential direction or are attached to at least one side surface of a rotor arm.

For example, the stator or rotor elements can be slipped onto or from the stator or rotor arms. A particularly simple exchange is advantageously possible.

Gluing the stator or rotor elements onto a side surface of the stator or rotor arms is also conceivable.

In one embodiment of the invention, the stator elements of the at least one stator and / or the rotor elements of the at least one rotor can be controlled individually. Magnetic forces acting between the stator and rotor elements can advantageously be controlled. A particularly low-loss operation of the electrical machine is possible.

The control of the stator and / or rotor elements can preferably be regulated.

Although it is conceivable that, in order to generate a torque, an activation takes place in such a way that only attractive or only repulsive magnetic forces act between neighboring stator and rotor elements, neighboring stator and rotor elements are expediently activated in such a way that between a first rotor element and a first stator element that is closer to the first rotor element than a second Stator element, a repulsive magnetic force acts and an attractive magnetic force acts between the first rotor element and the second stator element. A higher torque can advantageously be generated. Interfering torques which reduce the efficiency are also advantageously prevented.

A device for determining an angular position of

Rotor arms of the at least one rotor are provided, which preferably comprises at least one sensor which is arranged on a stator arm of the at least one stator or on a rotor arm of the at least one rotor. By controlling individually controllable stator and / or rotor elements depending on the angular position, particularly efficient operation of the electrical machine is advantageously possible. It can also be ensured that a particularly high torque can be generated.

In one embodiment of the invention, the rotor is shell-shaped and a disk-shaped stator is arranged at least partially within the rotor shell. An electrical machine that is particularly well protected from contamination during operation is advantageously created. The shell-like or disk-shaped design does not require the stator or rotor to be made from a solid material; a design with stator or rotor arms is conceivable. A bowl-shaped rotor can for example have ends of rotor arms which are bent in the direction of the stator.

The electrical machine is expediently designed as a generator, which is advantageously particularly easy to maintain.

It is conceivable that the electrical machine is designed as a three-phase synchronous machine, three-phase asynchronous machine, for example as a motor or generator, or as a reluctance motor.

The invention is explained in more detail below with reference to exemplary embodiments and the attached drawings relating to the exemplary embodiments. Show it:

1 shows a first embodiment of an electrical machine according to the invention,

2 shows a second embodiment of an electrical according to the invention

Machine, 3 details of an electrical machine according to the invention,

4 shows a further embodiment of an electrical according to the invention

Machine,

5 shows a particular embodiment of an electrical device according to the invention

Machine,

6 shows a further particular embodiment of an inventive

electric machine,

7 shows an embodiment of an electrical machine according to the invention, the

Rotor is designed as a rim for an electrically operated motor vehicle. An electric drive 1, shown schematically in a side view in FIG. 1 a and in a top view in FIG. 1 b, comprises a stator 2 with eight straight and equally long stator arms 4 extending radially away from an axis of rotation 3 of the drive 1, on each of which three Stator elements 5-7 spaced apart from one another in the longitudinal direction of the stator arm are attached. The stator elements 5-7 are designed as individually controllable coils which can be slipped onto the stator arms 4 and have copper wire and which completely enclose the stator arms 4 in the circumferential direction.

A rotor 8 shown in dashed lines comprises seven straight rotor arms 9 of equal length, on each of which three rotor elements 10-12, which are spaced apart from one another in the radial direction and designed as permanent magnets, are attached.

The diameter of the rotor 8 is larger than the diameter of the stator 2.

Because the stator 2 and the rotor 8 are arranged at a distance from one another in the axial direction of the axis of rotation 3, there is a between the stator 2 and the rotor 8

A perforated disk-shaped gap 13 is formed which encloses a shaft 14 of the drive 1.

One direction of rotation of the drive 1 is denoted by 15 in this exemplary embodiment.

Although not shown in Fig. 1, it is conceivable that rotor elements 10-12 as individually

controllable coils are formed. It is conceivable that the stator 4 or rotor arms 9 have a different straight shape than the straight shape shown in FIG. 1, for example are curved sinusoidally.

Reference is now made to FIG. 2, where parts that are the same or function in the same way are designated by the same reference number as in FIG. 1 and the letter a is added to the relevant reference number.

An electric drive la shown schematically in a side view in FIG. 2 differs from that shown in FIG. 1 in that three sensors 16 are attached to each rotor arm 9a of a rotor 8a, each in the radial direction on a rotation axis 3a facing side of a rotor element 10a-12a are attached and which are set up to determine an angular position of each rotor element 10a-12a of the rotor 8a. A device 17 for determining the angular position of the rotor 8a determines the angular position on the basis of a signal from the sensors 16. A

Device 18 for controlling stator elements 5a-7a designed as coils controls them as a function of the angular position such that attractive and / or repulsive magnetic forces act between rotor elements 10a-12a and stator elements 5a-7a of two adjacent stator arms 4a. Reference is now made to FIG. 3, where parts that are the same or function in the same way are designated by the same reference numbers as in FIGS. 1 and 2 and the letter b is added to the relevant reference number.

The method for operating an electrical machine according to the invention is explained with reference to FIG. 3.

In a section of a schematically illustrated electrical machine la shown in a plan view in FIGS. 3a and 3b, a rotor arm 9b is located, for example, in two different angular positions between two adjacent stator arms 19, 20 of a stator 2b. A distance 21-23 from stator elements 24-26 to rotor elements 10b-12b and a distance 27-29 from stator elements 30-32 become by sensors 16b of a device not shown in FIG. 3 for determining the angular position of rotor 8b

Rotor elements 10a-12a determined.

If the distances 21-23, as shown in FIG. 2a, are smaller than the distances 27-29, a control device (not shown in FIG. 3) controls the stator elements 24-26 in such a way that between the stator elements 24-26 and the rotor elements 10a-12a repulsive Magnetic forces and magnetic forces which attract between the stator elements 30-32 and the rotor elements 10a-12a act. A particularly high torque can advantageously be generated.

It is conceivable that the electrical machine lb is operated by between the

Only repelling magnetic forces act between the stator elements 24-26 and the rotor elements 10a-12a, or only attractive magnetic forces act between the stator elements 30-32 and the rotor elements 10a-12a. In this way, for example, energy-saving operation is possible, in particular with reduced torque.

Furthermore, it is conceivable that an angular position is determined without sensors 16a, 16b by storing these as speed-dependent values in a memory of the control device 17 and being able to call them up.

Reference is now made to FIG. 4, where parts that are the same or have the same effect are denoted by the same reference numbers as in FIGS. 1 to 3 and the letter c is added to the relevant reference number.

An electric drive lc shown schematically in a top view in FIG. 4 differs from that shown in FIGS. 1 to 3 in that free ends 33 of

adjacent rotor arms 9c of a rotor 8c are connected to one another by circular arc-shaped rods 34. The rotor is thus designed in the shape of a disk.

Although not shown in FIG. 4, it is conceivable that free ends of a stator 2a are connected to one another, as a result of which a disc-shaped design of the stator 2a is possible.

Reference is now made to FIG. 5, where parts that are the same or function in the same way are denoted by the same reference numbers as in FIGS. 1 to 4 and the letter d is appended to the relevant reference number.

An electric drive ld, shown schematically in a side view in FIG

differs from those shown in FIGS. 1 to 4 in that a stator 2d is designed in the form of a disk, while a rotor 8d is designed in the form of a shell. For this purpose, free ends 33d of rotor arms 9c of rotor 8d are bent in the direction of stator 2d and provided with permanent-magnetic, preferably bent rotor elements 12d. Reference is now made to FIG. 6, where parts that are the same or function in the same way are denoted by the same reference numbers as in FIGS. 1 to 5 and the letter e is added to the relevant reference number. An electric drive le, shown schematically in a side view in FIG. 6

differs from those shown in FIGS. 1 to 5 in that a cascade 34 of stators 2e and rotors 8e which are arranged alternately spaced in the axial direction of an axis of rotation 3e is provided.

Each stator 2e is fixedly attached to a hollow cylindrical pipe section 35 of a pipe 36. The tube 36 is designed as a guide tube for a shaft 14e on which the rotors 8e are arranged.

Reference is now made to FIG. 7, where parts that are the same or have the same effect are denoted by the same reference numbers as in FIGS. 1 to 6 and the letter f is added to the relevant reference number.

An electric drive lf, shown schematically in a partially sectioned side view in FIG. 7, differs from that in FIGS. 1 to 6 in that a rotor 8f is designed as a rim of a motor vehicle wheel 38 having a tire 37. Rotor arms 9f are designed as rim spokes. A shaft 14f is rotatably mounted on a side facing away from the rim and is connected to a motor vehicle not shown in FIG. 7, for example on a steering knuckle.

It goes without saying that all possible combinations of features of the features shown in FIGS. 1 to 7 are conceivable. For example, an electric drive shown in FIG. 5 can have sensors according to FIG. 2.

It is also understood that the electrical machine 1-lf shown in FIGS. 1 to 7 can be designed as a generator.

If the electrical machine lf is designed as a generator, it can be, for example, a braking energy recuperation unit.

Claims

1. Electric machine (1-lf), in particular electric drive (1-lf), which has at least one stator (2-2f) with magnetic or magnetizable stator elements (5-7; 5a-7a; 24-26, 30-32; 5c-7c; 5d-7d; 5e-7e; 5f-7f) and at least one rotor (8-8f) with magnetic or magnetizable rotor elements (10-12; 10a- 12a; 10b- 12b;

10c-12c; 10d-12d; 10e-12e; 10f-12f),

characterized,

that at least one of the stator elements (5-7; 5a-7a; 24-26, 30-32; 5c-7c; 5d-7d; 5e-7e; 5f-7f) and at least one of the rotor elements (10-12; 10a- 12a; 10b-12b;

10c-12c; 10d-12d; 10e-12e; 10f-12f) are arranged at a distance from one another in the axial direction of an axis of rotation (3-3f) of the electrical machine (1-lf).

2. Electrical machine according to claim 1,

characterized,

that a perforated disk-shaped gap (13; 13a; 13d-13f) is formed between the rotor (8-8f) and the stator (2-2f).

3. Electrical machine according to claim 1 or 2,

characterized,

the at least one rotor (8c) and / or the at least one stator is or are disc-shaped.

4. Electrical machine according to one of claims 1 to 3,

characterized,

that several rotor (9-9f) and / or several stator arms (4; 4a; 19,20; 4c-4f) are provided on which the stator (5-7; 5a-7a; 24-26, 30- 32; 5c-7c; 5d-7d; 5e-7e; 5f-7f) and / or the rotor elements (10-12; 10a- 12a; 10b-12b; 10c-12c; 10d-12d; lOe- 12e; 10f- 12f) are arranged, and preferably with a radial

Extend direction component away from the axis of rotation (3-3f).

5. Electrical machine according to one of claims 1 to 4,

characterized,

that several rotor (9-9f) and / or several stator arms (4; 4a; 19,20; 4c-4f) are provided to which the stator and / or rotor elements are attached, the rotor (9- 9f) and / or the stator arms (4; 4a; 19,20; 4c-4f) in one Disc plane of the at least one rotor (8-8f) and / or the at least one stator are arranged.

6. Electrical machine according to one of claims 1 to 5,

characterized,

that a number of rotor arms (9-9f) of the at least one rotor (8-8f) is different from a number of stator arms (4; 4a; 19,20; 4c-4f) of the at least one stator (2-2f).

7. Electrical machine according to one of claims 1 to 6,

characterized,

that each stator arm (4; 4a; 19,20; 4c-4f) of the at least one stator (2-2f) has a plurality of stator elements which are arranged along the stator arm at a distance from one another and / or each rotor arm (9-9f) of the at least one rotor (8-8f) has a plurality of rotor elements which are arranged at a distance from one another along the rotor arms.

8. Electrical machine according to one of claims 1 to 7,

characterized,

that the diameter of the at least one rotor (8-8f) is greater than the diameter of the at least one stator (2-2f).

9. Electrical machine according to one of claims 1 to 8,

characterized,

that the stator elements (5-7; 5a-7a; 24-26, 30-32; 5c-7c; 5d-7d; 5e-7e; 5f-7f) at least partially enclose a stator arm of the at least one stator in the circumferential direction or at least a side face of a stator arm are attached and / or the rotor elements (10-12; 10a-12a; 10b-12b; 10c-12c; 10d-12d; 10e-12e; 10f-12f) of the at least one rotor have a rotor arm in the circumferential direction at least partially enclose or are attached to at least one side surface of a rotor arm.

10. Electrical machine according to one of claims 1 to 9,

characterized,

that the stator elements (5-7; 5a-7a; 24-26, 30-32; 5c-7c; 5d-7d; 5e-7e; 5f-7f) of the at least one stator (2-2f) and / or the rotor elements (10-12; 10a-12a; 10b- 12b; 10c- 12c; 10d-12d; 10e-12e; 1 at least one rotor (8-8f) can be controlled individually.

11. Electrical machine according to one of claims 1 to 10,

characterized,

that a device (17) for determining an angular position of rotor arms of the at least one rotor is provided, which preferably comprises at least one sensor (16; 16b) which is arranged on a stator arm of the at least one stator or on a rotor arm of the at least one rotor.

12. Electrical machine according to one of claims 1 to 11,

characterized,

that the rotor (8d) is shell-shaped and a disk-shaped stator (2d) is arranged at least partially within the rotor shell.

13. A method for operating an electrical machine (1-lf), in particular for operating an electrical drive (1-lf), in which at least one rotor (8-8f) with magnetizable or magnetically designed rotor elements (10 -12; 10a- 12a; 10b- 12b; 10c-12c; 10d-12d; 10e-12e; 10f-12f) relative to a stator with radially extending, magnetizable or magnetically designed stator elements (5-7; 5a- 7a; 24-26, 30-32; 5c-7c; 5d- 7d; 5e-7e; 5f-7f) is rotated,

characterized,

that rotor (10-12; 10a- 12a; 10b-12b; 10c-12c; 10d-12d; 10e-12e; 10f-12f) and / or stator elements (5-7; 5a-7a; 24-26, 30 -32; 5c-7c; 5d-7d; 5e-7e; 5f-7f) can be controlled by a control device (18).

14. The method according to claim 13,

characterized,

that the control takes place as a function of an angular position of rotor arms (9-9f) of the at least one rotor (8-8f).

15. The method according to claim 13 or 14,

characterized,

that adjacent stator (5-7; 5a-7a; 24-26, 30-32; 5c-7c; 5d-7d; 5e-7e; 5f-7f) and rotor elements (10-12; 10a-12a; 10b- 12b; 10c- 12c; 10d-12d; 10e-12e; 10f-12f) are controlled in such a way that between a first rotor element (10b-12b) and a first stator element (24-26), which is connected to the first rotor element (10b-12b ) is closer than a second stator element (30-32), a repulsive magnetic force acts and an attractive magnetic force between the first rotor element (10b-12th stator element (30-32)).

16. Rim (8f) for an electrically powered motor vehicle, in particular one

Passenger car, a truck or a motorcycle, which is designed as a rotor of an electrical machine according to one of Claims 1 to 12.

17. rim according to claim 16,

characterized,

that at least some of the rim spokes are designed as rotor arms (9-9f) of the rotor (8-8f).