WO2015007441A2

WO2015007441A2 - Electric machine and arrangement of electric machines

Info

Publication number: WO2015007441A2
Application number: PCT/EP2014/062503
Authority: WO
Inventors: Daniel Wolf
Original assignee: Zf Friedrichshafen Ag
Priority date: 2013-07-16
Filing date: 2014-06-16
Publication date: 2015-01-22
Also published as: WO2015007441A3; DE102013213847A1

Abstract

Disclosed is an electric machine in the form of a motor (M1, M2) or generator comprising at least two rotors (1) and a stator assembly (2), the rotors (1) being radially offset relative to one another. Also disclosed is an arrangement comprising multiple electric machines, said machines in the form of motors (M1, M2) being directly or indirectly connected to one member or to different members of gearing (3) connected downstream.

Description

Electric machine and arrangement of electrical machines

The present invention relates to an electric machine and an arrangement of electric machines according to the closer defined in the preamble of claim 1 and 21, respectively.

From vehicle technology, various electrical machines are known as a motor or generator. In addition to various types of motors, such as rotary motors or linear motors, there are also different designs of electrical machines, such as a synchronous, asynchronous or reluctance machine.

For example, from the document DE 10 2009 028 151 A1 an electric actuator with a rotationally fixed stator is known by a main rotor is arranged. The main rotor corresponds to the greater part of the length of the stator, while a smaller part of the axial length of the stator is occupied by a rotor section arranged coaxially with the main rotor. The main rotor is used for drive purposes, while the simultaneously activated rotor section is used to release a load torque lock. The only pole of the stator is simultaneously with the corresponding pole of main rotor and rotor section in the magnetic flux.

The present invention is based on the object to propose an electric machine, which realizes a maximum power density with the simplest possible design.

This object is achieved by the features of claim 1 and 21, wherein advantageous embodiments of the dependent claims, the description and the drawings are removable.

Thus, an electric machine is proposed as a motor or generator with at least two rotors and a common stator arrangement, in which the rotors are arranged radially offset from each other. Due to the construction method that Rere rotors are assigned to a stator and the rotors are radially offset from each other, there is a particularly simple construction and the possibility that the transmitted torque can be divided among the rotors, which also lightweight materials for the transmission elements can be used in an advantageous manner.

The radially offset from each other rotors arranged, for example, parallel to the axis or axially offset from each other. However, it is also conceivable that the rotors are arranged with respect to their respective axis of rotation at a predetermined angle to each other. In this way, arched stator arrangements can also be used by the staggered rotors. It is also conceivable that the rotor axes protrude in a star shape inwards or outwards, for example.

In the electric machine proposed according to the invention, the magnetic poles of each coil of the stator arrangement are assigned to different rotors. Thus, the poles of a coil of the stator assembly with more than one rotor are in the magnetic flux.

By constructing and interconnecting a plurality of rotor-stator assemblies, the stator consists of individual coils, e.g. can be plugged together by positive or non-positive connections to each other or in the housing. The windings of the coils in the stator arrangement can thereby be wound as simply as possible. The pole pieces of the coils of

Stator arrangement can be summarized according to the geometric symmetry to the same parts. Thus, the manufacturing cost can be reduced.

By dividing the torque generated by the electric machine on a plurality of rotors lightweight materials can be used as a material for the gears or the like for power transmission. For the proposed embodiment of rotors and stator assembly can be advantageously the electrical control or the power electronics of the proposed electric machine can be carried out in a conventional manner, without the additional components or electrical components would be required.

In the proposed electric machine different motor designs for the stator assembly and the rotor, such as synchronous, asynchronous, BLDC machines or reluctance machines or the like can be used or combined with each other to combine the advantages of different engine variants. The formation of the magnetic fields in the rotors and the stator assembly can be realized by means of permanent magnets, by means of external excitation or by induction. It is also conceivable that the aforementioned embodiments are combined. In this way, the proposed electric machine can be designed as a motor or generator very flexible.

In the electric machine proposed according to the invention with at least two rotors provided, the rotors can be connected directly or indirectly to one or more members of a downstream transmission or the like. In this way, the rotors can be combined by means of a gear stage to a common output. Thus, the rotors are on the output side with a gear stage in operative connection, the rotors with the same or opposite direction of rotation on a common drive member, such as a driven member or a fixed member of a transmission, for example, a gear train, a friction gear, a crank gear, a cam gear, a Circulating gear, a planetary gear or the like, act. It is also conceivable that the rotors act on two different members of the transmission and the remaining member forms the output.

By acting on a common drive member, a torque superposition of the rotors can take place at the same output speed. By combining the rotors, a gear ratio is realized in the sense of a geared motor. It is also possible that the rotors are connected via different ratios to the output. By acting on two different members of the transmission is a superposition of speeds and moments in Ab- Depending on the selected transmission scheme possible, so that very high overall ratios or high-speed drives are feasible.

The stator assembly of the proposed electric machine may also include pole pieces and windings of the coils associated with only one rotor. These form at least one pair of poles, which form a magnetically closed flux through a laminated core, for example U-shaped or a half-stator of conventional design.

The object underlying the invention is also achieved by an arrangement with several of the electric machines proposed according to the invention, in which the electric machines are connected directly or indirectly to a member or to different members of a downstream transmission.

By acting on a common drive member, a torque superposition of the two electrical machines or motors can be carried out at the same output speed. By combining the drives a gear ratio in the sense of a geared motor is realized.

By acting on two different members of a transmission, a superposition of the speeds and moments depending on the selected transmission scheme is possible, so that a very high overall ratio arises. Thus, a speed superposition is realized by a power split.

By arranging a plurality of electrical machines as motor arrangements, it is possible to interconnect a system or network in geometrically regular or even irregular patterns. For the sake of simplicity, only the use of the identical part strategy in geometrically symmetrical arrangement is described. The arrangement pattern of the rotors does not necessarily have to be arranged concentrically. Other types of transmission and arrangements for interconnecting, grouping or clusters of drives in the sense of the above-described embodiments are possible. In particular gear sets of Lepelletier or Ravigneaux are possible in combination with rotationally symmetric stator arrangements. The wide ren between at least one engine and the engagement in the transmission, a switchable clutch of any design can be arranged to influence the degree of torque superposition or power split.

The present invention will be further explained with reference to the drawings. Show it:

1 is a schematic view of a first embodiment of an electric machine according to the invention with two 1-pole rotors and two coils of a stator assembly.

FIG. 2 shows a schematic view of a second embodiment variant of the electric machine with two 1-pole rotors and four coils of the stator arrangement; FIG.

3 and 3A a schematic view of a third embodiment of the electric machine with a 4-pole stator arrangement with four rotors;

4 and 4A a schematic view of a fourth embodiment of the electric machine with three rotors and a 3-pole stator arrangement;

5 and 5A a schematic view of a fifth embodiment of the electric machine as a three-phase machine with six rotors in hexagonal arrangement;

Fig. 6 is a schematic view of a sixth embodiment of the electric machine with five rotors in a square arrangement;

Figure 7 is a schematic view of a seventh embodiment of the electric machine with seven rotors in hexagonal arrangement. 8 is a schematic view of an eighth embodiment of the electric machine with eight rotors in an annular arrangement;

Fig. 9 is a schematic view of an arrangement with a plurality of electric machines connected to different members of a downstream transmission;

10 shows an arrangement with two electric machines, which are connected to the same member of the downstream transmission. and

Fig. 1 1 is a schematic view of another embodiment of the arrangement with two electrical machines, which are connected to the same member of the transmission.

In the figures, various embodiments of an electric machine according to the invention as a motor or generator with multiple rotors 1 and a stator 2 are shown in which the rotors 1 are arranged radially offset from one another. Furthermore, different embodiments of an arrangement of a plurality of electrical machines are shown in the figures, which are connected to a downstream transmission 3.

In Fig. 1, a first embodiment is shown, in which two 1-pole rotors 1 are provided, which are associated with a 2-pole stator 2. The rotor-side pole pair is exemplified by permanent magnets having a magnetic north pole N and a magnetic south pole S. In the coils 4 of the stator assembly 2, the magnetic poles are also marked with N and S.

In Fig. 2, a second embodiment of the electric machine is shown, in which the two 1-pole rotors 1, a 4-pole stator 2 is assigned. Regardless of the two embodiments, the stator assembly 2 is constructed similar to a salient pole, wherein the pole pieces of the coil 4 but with two different rotors 1 are in magnetic contact or flux. The control of the coils 4 can take place via a single-phase alternating current according to FIG. 1 and in FIG. 2, for example via a two-phase rotating field with alternating current with 180 ° phase shift, so that the electric machine can be operated as an asynchronous motor or synchronous motor. Furthermore, all known forms of BLDC control are applicable. Optionally, both rotors 1 may be equipped with speed sensors, so that only the rotor position of a rotor 1 is taken into account in the control and the respective other rotor is entrained.

In Fig. 3 and 3A, a third embodiment of the electric machine is provided with four 1-pole rotors 1, wherein the four 1-pole rotors 1 are arranged in cross section with respect to their axes of rotation square or rectangular. The rectangular, preferably square stator arrangement 2 with the four rotors 1 schematically shows, in a simplified manner, the magnetic flux in the stator arrangement 2 through the rotors 1 of the electric machine. The respective direction of rotation of the rotors 1 symbolized by a circle is indicated by a corresponding arrow. Fig. 3A shows only a schematic representation of the electrical machine, in which the dashed lines indicate the magnetic flux through the respective coil 4 and the pole piece of the stator assembly 2 and the respective rotor 1 to the next pole piece. On the connecting line between the rotors 1, the coil winding of the stator assembly 2 is arranged. Advantageously, the coils of the stator assembly 2 can be wound orthocyclically and arranged so that as little space as possible remains in the stator assembly 2, so that a particularly space-saving arrangement is possible.

In the embodiment variant shown in FIGS. 3 and 3A, the stator arrangement 2 is arranged such that each of the four 1-pole rotors 1 is assigned four pole pairs. 4 and 4A, a fourth embodiment of the electric machine according to the invention is shown in which three 3-pole rotors 1 are provided, wherein the three 3-pole rotors 1 are arranged triangular in cross section with respect to their axes of rotation. The stator arrangement 2 is arranged such that each of the 3-pole rotors 1 are assigned three pole pairs of the stator arrangement 2. FIG. 3A again schematically shows the magnetic flux in this embodiment variant.

Preferably, the fourth embodiment of the electric machine can be implemented as a BLDC machine. The triangular, preferably isosceles stator arrangement 2 with three rotors 1 can also be designed, for example, as a 3-phase three-phase machine (asynchronous machine). In the asynchronous machine, a revolving pole pair in the stator arrangement 2 is generated by the three phases. In the embodiment as a BLDC electric motor, three pole pairs are formed in the stator 2 and in the rotor 1.

FIGS. 5 and 5A schematically illustrate a fifth embodiment of the electrical machine in which six rotors 1 are assigned to a plurality of three-phase three-phase fields of the stator arrangement 2 for realizing a three-phase machine. The rotors 1 are arranged hexagonally in cross section with respect to their axes of rotation. In FIG. 5A, the interconnection of the three phases u, v, w or -u, -v, -w of a three-phase machine is shown by way of example, as a result of which alternately changing directions of rotation occur in the rotors 1. A version as a BLDC machine is also possible. The different directions of rotation are indicated by arrows in Figures 5 and 5A.

In Fig. 6, a sixth embodiment is shown schematically, are provided in the five 2-pole rotors 1, which are arranged square in cross section with respect to their axes of rotation, wherein one of the rotors 1 is arranged centrally to the square arrangement. The stator assembly 2 is provided such that each of the rotors 1 are assigned two pole pairs. This geometric arrangement of rotors 1 and the stator assembly 2 allows a 4-pole arrangement with five rotors. 1 In Fig. 7, a seventh embodiment of the electric machine is shown schematically, in which seven 3-pole rotors 1 are provided, which are arranged hexagonally in cross section with respect to their axes of rotation, wherein one of the rotors 1 is arranged centrally to the hexagonal arrangement. The stator assembly is designed such that each of the rotors 1 are assigned three pole pairs. This design variant can be implemented, for example, for 6-pole BLDC or 2-pole three-phase machines with 7 rotors 1.

8 shows an eighth embodiment variant of the electrical machine in which eight rotors 1 are assigned to a plurality of three-phase three-phase fields of the stator arrangement 2 for realizing a three-phase machine, wherein the rotors 1 are approximately annular in cross-section with respect to their axes of rotation. A larger number of rotors 1 is arranged analogously. Preferably, this type of electrical machine can be designed for BLDC machines.

The arrangements of several electrical machines shown in FIGS. 9 to 11 are also applicable to the arrangement of several rotors 1 of only one electric machine. In this embodiment, the rotors 1 are then connected directly or indirectly to the same or the same member or to different members of a downstream transmission 3.

In the arrangement of various electrical machines e.g. As motors M1 and M2 it is provided that the first motor M1 and the second motor M2 are connected to either the same or the same member, as shown in FIGS. 10 and 11, or to various members, as shown in FIG Getriebes 3 are connected directly or indirectly.

In Fig. 9, a so-called speed superposition is represented by power split, since the electric machine is connected as a first motor M1 with a ring gear 5, for example, a planetary gear set 3, while the electric machine as a second motor M2 with the sun gear 6 of the planetary as Gear 3 is connected. In this embodiment, the planetary gear carrier 7 of the transmission as output. A dashed line indicates an optional coupling of the two motors M1 and M2.

In Figs. 10 and 11, the motors M1 and M2 formed as electric machines have different ratios, and are connected to the same member of the transmission 3.

For example, in FIG. 10, the first motor M1 is connected to a spur gear 8 via a gear ratio i1, the second motor M2 also being connected to the spur gear 8 via another gear stage i2. Again, an optional coupling of the two motors M1 and M2 is indicated by dashed lines.

In Fig. 1 1, the first motor M1 is coupled to the transmission stage i1 with a ring gear 9, while the second motor M2 is also connected to a gear stage i2 with the ring gear 9.

REFERENCE CHARACTERS

1 rotor

2 stator arrangement

3 gears

4 coil

5 ring gear of the planetary gear set

6 Sun gear of the planetary gear set

7 planet carrier of the planetary gear set

8 spur gear

9 ring gear

M1 engine

M2 engine

N magnetic north pole

S magnetic south pole

u, -u phase at three-phase current

v, -v phase at three-phase current

w, -w phase at three-phase current

Claims

claims

1 . Electric machine as a motor (M1, M2) or generator with at least two rotors (1) and a stator assembly (2), characterized in that the rotors (1) are arranged radially offset from each other.

2. Electrical machine according to claim 1, characterized in that the rotors (1) are arranged axially parallel to each other with respect to the respective axis of rotation.

3. Electrical machine according to claim 1, characterized in that the rotors (1) are arranged relative to the respective axis of rotation at a predetermined angle to each other.

4. Electrical machine according to one of the preceding claims, characterized in that the magnetic poles (N, S) of each coil (4) of the stator assembly are assigned to different rotors (1).

5. Electrical machine according to one of the preceding claims, characterized in that each rotor (1) and each stator assembly (2) has at least one magnetic field by a permanent magnet or by external excitation or by induction.

6. Electrical machine according to one of the preceding claims, characterized in that two at least 1-pole rotors (1) are provided which are associated with a 2-pole stator assembly (2) or a 4-pole stator assembly (2).

7. Electrical machine according to one of the preceding claims, characterized in that at least 1-pole rotors (1) are provided, which are assigned to a 2m-pole stator arrangement, where n and m are integers, such as 1, 2, 3, 4. ...describe.

8. Electrical machine according to one of the preceding claims, characterized in that four at least 1-pole rotors (1) are provided.

9. Electrical machine according to claim 7, characterized in that the four at least 1-pole rotors (1) are arranged in cross section with respect to their axes of rotation square or rectangular.

10. Electrical machine according to claim 9, characterized in that the stator assembly (2) is designed such that each of the four at least 1-pole rotors (1) 2n pole pairs, in particular a lot of pole pairs are assigned, where n is an integer, such as 1 , 2, 3, 4 ....

1 1. Electrical machine according to one of the preceding claims, characterized in that 3n 3-pole rotors (1), in particular three 3-pole rotors are provided, wherein n denotes an integer, such as 1, 2, 3 ....

12. Electrical machine according to claim 1 1, characterized in that the 3n 3-pole rotors (1) in cross-section with respect to their axes of rotation are triangular arranged in a triangular.

13. Electrical machine according to claim 1 1 or 12, characterized in that the stator assembly (2) is designed such that each of the 3-pole rotors (1) 3n pole pairs are assigned, in particular three pole pairs are assigned, where n is an integer as 1, 2, 3 .... referred.

14. Electrical machine according to one of the preceding claims, characterized in that six rotors (1) are associated with at least 3-phase three-phase fields of the stator assembly (2) for realizing a three-phase machine.

15. Electrical machine according to claim 14, characterized in that the rotors (1) are arranged hexagonal in cross section with respect to their axes of rotation.

16. Electrical machine according to one of the preceding claims, characterized in that five at least 2-pole rotors (1) are provided, which are arranged square in cross section with respect to their axes of rotation, wherein one of the rotors (1) is arranged centrally to the square arrangement ,

17. Electrical machine according to claim 16, characterized in that the stator arrangement (2) are arranged such that each of the rotors (1) are assigned at least two pole pairs.

18. Electrical machine according to one of the preceding claims, characterized in that seven at least 3-pole rotors (1) are provided, which are arranged hexagonal in cross section with respect to their axes of rotation, wherein one of the rotors (1) is arranged centrally to the hexagonal arrangement ,

19. Electrical machine according to claim 18, characterized in that the stator arrangement (2) are arranged such that each of the rotors (1) are assigned at least three pole pairs.

20. Electrical machine according to one of the preceding claims, characterized in that eight rotors (1) are assigned at least three-phase three-phase fields of the stator assembly (2) for realizing a three-phase machine, wherein the rotors are arranged in cross-section with respect to their axes of rotation annular.

21. Electrical machine according to one of the preceding claims, characterized in that the rotors (1) are connected directly or indirectly to one or more members of a downstream transmission (3).

22. Arrangement with a plurality of electric machine according to one of the preceding claims, characterized in that the electric machines are connected as motors (M1, M2) with a member or with different members of a downstream transmission (3) directly or indirectly.

23. The arrangement according to claim 22, characterized in that a first motor (M1) with a ring gear (5) of the transmission (3) is connected, and that a second motor (M2) with a sun gear (6) of the transmission (3) connected is.

24. Arrangement according to claim 22, characterized in that a first motor (M1) via a translation stage (i1) with a spur gear (8) is connected, and that a second motor (M2) via another translation stage (i2) with the spur gear (8) is connected.

25. Arrangement according to claim 22, characterized in that a first motor (M1) with a transmission stage (i1) with a ring gear (9) is connected, and that a second motor (M2) with a further transmission stage (i2) with the ring gear (9) is connected.