Hybrid rotor for an axial flux electrical machine

Abstract

The present invention provides a rotor, an axial flux electrical machine and a hybrid-electrical or electrical air craft. The rotor for the axial flux electrical machine comprises first sections of a first material and second sections of a second material. The first sections and second sections are arranged in alternating order and ring-shape. The arrangement is characterized by third sections which form interface areas between the first sections and second sections, whereas the third sections are comprising the first material and the second material in such a manner that the first section and the second section are connected force-fitted.

Claims

1. An axial flux electrical machine, comprising: a stationary stator, a rotor rotatably mounted with respect to the stator and configured to rotate around an axis, the rotor comprising: first sections of a first material, and second sections of a second material, wherein the first sections and second sections are arranged in alternating order and ring-shaped, third sections circumferentially positioned between the first sections and the second sections to form circumferential interface areas between the first sections and second sections, wherein the third sections comprise both the first material and the second material overlapping one another in a circumferential direction and in such a manner that the first sections and the second sections are connected force-fitted.

2. The axial flux electrical machine according to claim 1, wherein the first material has a magnetic permeability higher than 10.sup.4 Hm.sup.−1 and the second material has a magnetic permeability under 10.sup.1 Hm.sup.−1.

3. The axial flux electrical machine according to claim 1, wherein the first material is an amorphous metal with a tensile strength over 1 GPa.

4. The axial flux electrical machine according to claim 1, wherein the second material is a structured material with a tensile strength over 1 GPa.

5. The axial flux electrical machine according to claim 1, wherein respective tensile strengths and tensile moduli of the first material and the second material differ by less than 20%.

6. The axial flux electrical machine according to claim 1, wherein: the first material is arranged in the first sections in ribbon stripes, which form magnetic rotor poles, the second material in the second sections form pole gaps, and the first material and the second material are arranged in interleaved laminations in the third sections.

7. The axial flux electrical machine according to claim 1, wherein the axial flux electrical machine is a reluctance-based machine.

8. A hybrid-electrical or electrical aircraft with the axial flux electrical machine according to claim 1.

9. The aircraft according to claim 8, wherein the aircraft is an airplane.

10. The axial flux electrical machine according to claim 1, wherein the first sections and second sections are arranged in a circumferentially alternating order around a ring at a same radius from the axis.

11. A rotor for an axial flux electrical machine, comprising: first sections of a first material, and second sections of a second material, wherein the first sections and second sections are arranged in alternating order and ring-shaped, third sections which form interface areas between the first sections and second sections, whereas the third sections comprise the first material and the second material in such a manner that the first section and the second section are connected force-fitted, wherein respective tensile strengths and tensile moduli of the first material and the second material differ by less than 20%.

12. A rotor for an axial flux electrical machine, comprising: first sections of a first material, and second sections of a second material, wherein the first sections and second sections are arranged in alternating order and ring-shaped, third sections which form interface areas between the first sections and second sections, whereas the third sections comprise the first material and the second material in such a manner that the first section and the second section are connected force-fitted, wherein: the first material is arranged in the first sections in ribbon stripes, which form magnetic rotor poles, the second material in the second sections form pole gaps, and the first material and the second material are arranged in interleaved laminations in the third sections.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a frontal view of a rotor,

(2) FIG. 2 shows a cross-sectional side view of a reluctance-based electrical machine and

(3) FIG. 3 shows an air plane with an electrical machine.

DETAILED DESCRIPTION OF THE INVENTION

(4) FIG. 1 shows a rotor 4 with first sections 1, second sections 2, and third sections 3. The first sections 1 consists of a first material, the second sections 2 consists of a second material, and the third sections 3 consist of the first and the second material in such a way that the first section and the second section are connected force-fitted. The first sections 1 and second sections 2 are arranged in alternating order and ring-shape. The third sections 3 form interface areas or overlapping zone between the first section 1 and second sections 2.

(5) The first material has a high magnetic permeability μ.sub.r (in the range of 10.sup.5, but higher than 10.sup.4 Hm.sup.−1) and the second material has a low magnetic permeability μ.sub.r (in the range of 1, but under 10.sup.1 Hm.sup.−1). Further, the first material is an amorphous metal with a tensile strength (σ.sub.max) over 1 GPa. This has the advantage of a high structural strength of the material.

(6) The second material is a structured material with a tensile strength σ.sub.max over 1 GPa. The second material can be for example carbon fibre reinforced plastic (CFRP) or any “thin ply” composite. This has the advantage of a high structural strength of the material and no ferro-magnetism.

(7) The first material is arranged in the first sections in ribbon-like stripes, which form magnetic rotor poles, the second material in the second sections form pole gaps, and the first material and the second material are arranged in interleaved laminations or layers/plies in the third sections.

(8) FIG. 2 shows a reluctance-based machine 5 with a rotor 4, two stators 8 and a rotation axis 9. The rotor 4 is arranged between the two stators 8 and rotates around the axis 9. The rotor is made up according to the design of FIG. 1

(9) FIG. 3 shows an air plane 6 with a reluctance-based electrical machine 5 according to FIG. 2, as an example of an electrical machine. The electrical machine 5 drives a propeller 7. The air plane 6 is an example for an aircraft.

(10) Although the invention has been explained in relation to its preferred embodiment(s) as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present invention. It is, therefore, contemplated that the appended claim or claims will cover such modifications and variations that fall within the true scope of the invention.