Rotor of an electric machine, electric machine, and method for producing a rotor of an electric machine

1. A rotor of an electric machine, said rotor having

a first rotor segment;

a second rotor segment connected onto the first rotor segment, wherein the second rotor segment is twisted relative to the first rotor segment by a first twist angle;

a third rotor segment connected onto the second rotor segment, wherein the third rotor segment is twisted relative to the second rotor segment by a second twist angle that differs from the first twist angle;

a fourth rotor segment connected onto the third rotor segment, wherein the fourth rotor segment is twisted relative to the third rotor segment by the second twist angle; and

a fifth rotor segment connected onto the fourth rotor segment, wherein the fifth rotor segment is twisted relative to the fourth rotor segment by the first twist angle; wherein each of the first rotor segment, second rotor segment, third rotor segment, fourth rotor segment and fifth rotor segment have a curved surface as well as a permanent-magnet structure arranged on a circumferential surface that is oriented coaxially to the curved surface;

wherein a contour of the permanent-magnet structure has a stepped section with several steps, wherein each step has a first extension that is oriented essentially perpendicularly to a circumferential direction of the circumferential surface as well as a second extension that is oriented parallel to the circumferential direction and that connects the first extension to a first extension of an adjacent step,

wherein the first extension of a first step differs from the first extension of a second step that is adjacent to the first step, and

wherein the second extension of the first step differs from the second extension of the second step.

2. The rotor according to claim 1 , whereby the stepped section is point-symmetrical, wherein a center of symmetry is situated in a plane of symmetry that is oriented parallel to the circumferential direction and that runs through a middle of the circumferential surface.

3. The rotor according to claim 1 , whereby the permanent-magnet structure has several permanent-magnet elements.

4. The rotor according to claim 3 , whereby

each permanent-magnet element has a rectangular, a trapezoidal or a parallelogram-shaped base area, and/or

at least one permanent-magnet element functions as a magnetic pole.

5. The rotor according to claim 3 , whereby the rotor has several rotor segments that each has a curved surface and that are firmly connected to each other, whereby the circumferential surface is arranged coaxially to the surfaces of the rotor segments, and whereby the permanent-magnet elements are embedded into the rotor segments or are attached to the surfaces of the segments.

6. The rotor according to claim 5 , whereby each rotor segment represents a step of the stepped section, whereby

the first extension of each step is smaller than an axial length of the appertaining rotor segment or equal to the axial length, and

the second extension of each step is achieved by a twist angle of the appertaining rotor segment relative to an adjacent rotor segment.

7. The rotor according to claim 1 , whereby a dimension of the stepped section in the circumferential direction extends over an arc of a circle having a mid-point angle.

8. The rotor according to claim 1 , whereby the contour of the permanent-magnet structure has a second stepped section whose shape corresponds to a shape of the first stepped section and which is shifted along the circumferential direction relative to the first stepped section.

9. An electric machine having a stator and a rotor according to claim 1 .

10. The rotor according to claim 1 , wherein the first twist angle is half as large as the second twist angle.

11. A method for producing a rotor of an electric machine, comprising the following:

providing a first rotor segment, a second rotor segment, a third rotor segment, a fourth rotor segment, and a fifth rotor segment, each having a curved surface as well as a permanent-magnet element arranged on a circumferential surface that is oriented coaxially to the curved surface, wherein:

a contour of the permanent-magnet structure has a stepped section with several steps, wherein each step has a first extension that is oriented essentially perpendicularly to a circumferential direction of the circumferential surface as well as a second extension that is oriented parallel to the circumferential direction and that connects the first extension to a first extension of an adjacent step,

the first extension of a first step differs from the first extension of a second step that is adjacent to the first step, and

wherein the second extension of the first step differs from the second extension of the second step;

connecting the second rotor segment onto the first rotor segment, whereby the second rotor segment is twisted relative to the first rotor segment by a first twist angle;

connecting the third rotor segment onto the second rotor segment, whereby the third rotor segment is twisted relative to the second rotor segment by a second twist angle that differs from the first twist angle;

connecting the fourth rotor segment onto the third rotor segment, whereby the fourth rotor segment is twisted relative to the third rotor segment by the second twist angle; and

connecting the fifth rotor segment onto the fourth rotor segment; whereby the fifth rotor segment is twisted relative to the fourth rotor segment by the first twist angle.

12. The method according to claim 11 , wherein the first twist angle is half as large as the second twist angle.