Magnetic coupling

• US 10,411,571 B2
• Filed: 05/27/2015
• Issued: 09/10/2019
• Est. Priority Date: 06/24/2014
• Status: Active Grant

• Current Assignee: Grundfos Holding A/S (POUL DUE Jensen's FOND)
• Original Assignee: Grundfos Holding A/S (POUL DUE Jensen's FOND)
• Inventors: Bendixen, Flemming Buus, Kjeldsteen, Peter, Sogaard, Allan Ivo
• Primary Examiner(s): Leung, Quyen P
• Assistant Examiner(s): Chang, Minki
• Application Number:
  US15/321,453
• Publication Number:
  US 20180212500A1
• Time in Patent Office: 1,567 Days
• Field of Search: 310 92, 310103, 310102 R, 310102 A
• CPC Class Codes: F04D 13/025 Details of the can separating the pump and drive area
• CPC Class Codes: F04D 13/027 Details of the magnetic circuit
• CPC Class Codes: H01F 13/003 Methods and devices for magnetising permanent magnets permanent magnets H01F7/02
• CPC Class Codes: H01F 41/028 Radial anisotropy for rotor or stator bodies H02K15/02
• CPC Class Codes: H02K 1/02 characterised by the magnetic material
• CPC Class Codes: H02K 15/03 having permanent magnets
• CPC Class Codes: H02K 16/005 Machines with only rotors, e.g. counter-rotating rotors DC commutator machines or universal AC/DC commutator motors having a rotating armature and a rotating excitation field H02K23/60
• CPC Class Codes: H02K 49/106 with a radial air gap
• CPC Class Codes: H02K 7/16 for operation above the critical speed of vibration of the rotating parts

Abstract

A magnetic coupling includes an inner rotor (11) and an outer rotor (9) which at least partly surrounds the inner rotor (11). These rotors (11, 9) each are formed of magnetic material (18) and are coupled to one another by way of magnetic forces. The inner rotor (11) and/or the outer rotor (9) contain powdery, magnetizable material (18). The powdery, magnetizable material (18) is magnetized at a side lying opposite the other rotor at several locations distributed over the periphery.

Claims

1. A magnetic coupling comprising:

an inner rotor; and

an outer rotor which at least partly surrounds the inner rotor, said rotors each comprising magnetic material and being coupled to one another by way of magnetic forces, wherein the inner rotor or the outer rotor or both the inner rotor and the outer rotor contain powdery magnetizable material which from a side lying opposite the other rotor, is magnetized at several locations distributed over a periphery thereof, at least one of the rotors comprising a hermetically closed receptacle, in which the magnetic material is arranged in a compacted form, wherein at least the receptacle of the outer rotor has a hollow-cylindrical shape and a ratio of a distance of adjacent magnetic poles along an inner peripheral surface of the outer rotor to a thickness of the magnetic material in the outer rotor is between 2 and 3.

2. A magnetic coupling according to claim 1, wherein the magnetization at several locations is such that in the coupled condition, a wavy-line distribution of the magnetic flux density exists between the rotors in planes transverse to the longitudinal middle axis and rotation axis of the coupling.

3. A magnetic coupling according to claim 1, wherein the magnetization at several locations is distributed over the periphery of the rotor at a same angular distance with respect to a common longitudinal middle axis and rotation axis of the coupling.

4. A magnetic coupling according to claim 1, wherein at least one of the rotors comprises an annular space which is open at least at one side and in which the magnetic material is arranged, in compacted form, wherein the powdery, magnetic material comprises a protective coating and an adhesive.

5. A magnetic coupling according to claim 4, wherein:

the annular space of the inner rotor has a hollow-cylindrical shape and a ratio of the a distance of adjacent magnetic poles along an outer peripheral surface of the inner rotor to a thickness of the magnetic material in the inner rotor is between 2 and 3.

6. A magnetic coupling according to claim 1, wherein at least the receptacle of the inner rotor has a hollow-cylindrical shape and a ratio of a distance of adjacent magnetic poles along an outer peripheral surface of the inner rotor to a thickness of the magnetic material in the inner rotor is between 2 and 3.

7. A magnetic coupling according to claim 1, wherein a permeability of an outer wall of the outer rotor, which surrounds the magnetic material, is between 1 and 2.

8. A magnetic coupling according to claim 1, wherein magnetic poles in the inner and in the outer rotor run obliquely seen in a longitudinal direction at an angle of between 10°

and 60°

.

9. A magnetic coupling according to claim 1, wherein magnetic poles in the inner and in the outer rotor run in a curvilinear manner seen in a longitudinal direction.

10. A magnetic coupling according to claim 1, wherein the powdery, magnetizable material consists of 0 to 50% by volume of soft-magnetic materials and of 50 to 100% by volume of hard-magnetic materials.

11. A magnetic coupling according to claim 1, wherein one of the rotors comprises permanent magnets which are arranged in a Halbach-array configuration.

12. A magnetic coupling according to claim 1, wherein the magnetic material in the rotor is formed by one or more fully or partially annular shaped bodies which are pre-shaped from powdery material.

13. A magnetic coupling comprising:

an inner rotor; and

an outer rotor which at least partly surrounds the inner rotor, said rotors each comprising magnetic material and being coupled to one another by way of magnetic forces, wherein the inner rotor or the outer rotor or both the inner rotor and the outer rotor contain powdery magnetizable material which from a side lying opposite the other rotor, is magnetized at several locations distributed over a periphery thereof, at least one of the rotors comprising a hermetically closed receptacle, in which the magnetic material is arranged in a compacted form, wherein at least the receptacle of the inner rotor has a hollow-cylindrical shape and a ratio of a distance of adjacent magnetic poles along an outer peripheral surface of the inner rotor to a thickness of the magnetic material in the inner rotor is between 2 and 3.

14. A magnetic coupling comprising:

an inner rotor; and

an outer rotor which at least partly surrounds the inner rotor, said rotors each comprising magnetic material and being coupled to one another by way of magnetic forces, wherein the inner rotor or the outer rotor or both the inner rotor and the outer rotor contain powdery magnetizable material which from a side lying opposite the other rotor, is magnetized at several locations distributed over a periphery thereof, at least one of the rotors comprising an annular space which is open at least at one side and in which the magnetic material is arranged, in compacted form, wherein the powdery, magnetic material comprises a protective coating and an adhesive, at least a receptacle of the outer rotor having a hollow-cylindrical shape and a ratio of a distance of adjacent magnetic poles along an inner peripheral surface of the outer rotor to a thickness of the magnetic material in the outer rotor is between 2 and 3, wherein the annular space of the outer rotor has a hollow-cylindrical shape and a ratio of a distance of adjacent magnetic poles along an inner peripheral surface of the outer rotor to a thickness of the magnetic material in the outer rotor is between 2 and 3.

15. A magnetic coupling comprising:

an inner rotor; and

an outer rotor which at least partly surrounds the inner rotor, said rotors each comprising magnetic material and being coupled to one another by way of magnetic forces, wherein the inner rotor or the outer rotor or both the inner rotor and the outer rotor contain powdery magnetizable material which from a side lying opposite the other rotor, is magnetized at several locations distributed over a periphery thereof, wherein at least one of the rotors comprises an annular space which is open at least at one side and in which the magnetic material is arranged, in compacted form, wherein the powdery, magnetic material comprises a protective coating and an adhesive, wherein at least a receptacle of the inner rotor has a hollow-cylindrical shape and a ratio of a distance of adjacent magnetic poles along an outer peripheral surface of the inner rotor to a thickness of the magnetic material in the inner rotor is between 2 and 3, the annular space of the inner rotor having a hollow-cylindrical shape and a ratio of the distance of adjacent magnetic poles along an outer peripheral surface of the inner rotor to a thickness of the magnetic material in the inner rotor is between 2 and 3.