Magnetic reluctance coupling having two rotors

Patent metadata

Field	Value
Publication number	US-9755495-B2
Application number	US-201314388613-A
Country	US
Kind code	B2
Filing date	Feb 14, 2013
Priority date	Mar 28, 2012
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

A simplified magnetic reluctance coupling for coupling a first shaft to a second shaft, has a hollow cylindrical stator which has at least one magnet that is/are distributed around the circumference of the stator. The reluctance coupling also has a first rotor, which is supported in such a way that it can rotate within the stator, is connected to a first shaft in a rotationally fixed manner, and has a plurality of ferromagnetic first portions distributed around the circumference thereof and spatially separated from one another, as well as a second rotor, which is supported in such a way that it can rotate within the first rotor, is connected to the second shaft in a rotationally fixed manner, and has a plurality of ferromagnetic second portions distributed around the circumference thereof.

First claim

The invention claimed is:

1. A magnetic reluctance coupling for coupling a first shaft to a second shaft, the magnetic reluctance coupling comprising:
a hollow-cylindrical stator including one or more magnets that are arranged around a circumference of the stator, wherein the stator includes two coaxial ferromagnetic rings and the one or more magnets are arranged between the two coaxial ferromagnetic rings;
a first rotor that is mounted inside the stator and is configured to rotate within the stator, the first rotor being fixed to the first shaft and configured to rotate with the first shaft, the first rotor including a plurality of ferromagnetic first portions that are arranged around a circumference of the first rotor and are separated from one another; and
a second rotor that is mounted inside the first rotor and is configured to rotate within the first rotor, the second rotor being fixed to the second shaft and configured to rotate with the second shaft, the second rotor including a plurality of ferromagnetic second portions that are arranged around a circumference of the second rotor;
wherein each of the ferromagnetic first portions of the first rotor is formed as a bar having three subportions, a first subportion of each bar being formed of ferromagnetic material and being arranged along an inner circumference of one of the two coaxial ferromagnetic rings, a second subportion of each bar being formed of ferromagnetic material and being arranged along an inner circumference of the other one of the two ferromagnetic rings, and a third subportion of each bar being formed of a non-magnetic material and being arranged axially between the first subportion and the second subportion.

2. The magnetic reluctance coupling as claimed in claim 1 , wherein each of the one or more magnets are electromagnets.

3. The magnetic reluctance coupling as claimed in claim 2 , wherein the stator includes two coaxial ferromagnetic rings and the one or more magnets are arranged between the two coaxial ferromagnetic rings, and each of the one or more electromagnets has a ferromagnetic core that acts as a connecting piece between the two coaxial ferromagnetic rings, so that there is an uninterrupted ferromagnetic connection between the two coaxial ferromagnetic rings.

4. The magnetic reluctance coupling as claimed in claim 1 , wherein the first rotor includes a disk-shaped holding element, the first shaft being fastened to a first side of the holding element and each of the bars being fastened to a second side of the holding element that is opposite the first side.

5. The magnetic reluctance coupling as claimed in claim 1 , wherein an axial length of the first rotor, an axial length of the second rotor, and an axial length of the stator are the same.

6. The magnetic reluctance coupling as claimed in claim 1 , wherein the ferromagnetic second portions of the second rotor are arranged in star form around an axis of rotation of the second rotor.

7. The magnetic reluctance coupling as claimed in claim 1 , wherein a number of the plurality of ferromagnetic first portions is equal to a number of the plurality of ferromagnetic second portions.

8. The magnetic reluctance coupling as claimed in claim 4 , wherein each of the bars extends longitudinally from the second side of the holding element and a longitudinal axis of each of the bars is parallel to an axis of rotation of the first shaft.

9. The magnetic reluctance coupling as claimed in claim 8 , wherein each of the bars is divided into the three subportions along the longitudinal axis.

10. The magnetic reluctance coupling as claimed in claim 1 , wherein the second rotor is formed as a single piece such that each of the ferromagnetic second portions merge together at a center portion of the second rotor that has a same axis of rotation as an axis of rotation of the second shaft.

11. The magnetic reluctance coupling as claimed in claim 1 , wherein the one or more magnets do not protrude into an interior of the stator, the interior of the stator being defined by a cylinder that is bounded by inner surfaces of the two coaxial ferromagnetic rings.

12. A coupling arrangement comprising:
a hollow-cylindrical stator including one or more magnets that are arranged around a circumference of the stator;
a first rotor that is mounted inside the stator and is configured to rotate within the stator, the first rotor being fixed to the first shaft and configured to rotate with the first shaft, the first rotor including a plurality of ferromagnetic first portions that are arranged around a circumference of the first rotor and are separated from one another; and
a second rotor that is mounted inside the first rotor and is configured to rotate within the first rotor, the second rotor being fixed to the second shaft and configured to rotate with the second shaft, the second rotor including a plurality of ferromagnetic second portions that are arranged around a circumference of the second rotor; and
a control device configured to activate a coupling-engaging state in which a first magnetic field in the first and second rotors is directed in a first direction and, immediately after ending the coupling-engaging state by current pulses, a second magnetic field in the first and second rotors is formed in a second direction opposite to the first direction to demagnetize the first and second rotors;
wherein each of the ferromagnetic first portions of the first rotor is formed as a bar having three subportions, a first subportion of each bar comprising ferromagnetic material arranged along an inner circumference of one of the two coaxial ferromagnetic rings, a second subportion of each bar comprising ferromagnetic material arranged along an inner circumference of the other one of the two ferromagnetic rings, and a third subportion of each bar comprising a non-magnetic material arranged axially between the first subportion and the second subportion.

Assignees

• Siemens Ag

Inventors

• Bachmaier Georg
• Bachmann Christian
• Bergmann Dominik
• Gerlich Matthias
• Goedecke Andreas
• Pais Guillaume
• Zoels Wolfgang

Classifications

• H02K49/10 Primary

  of the permanent-magnet type · CPC title

• H02K49/06

  of the synchronous type {(H02K49/10 takes precedence)} · CPC title

• H02K49/106 Primary

  with a radial air gap · CPC title