Magnetic bearing and rotary machine comprising such a bearing

Patent metadata

Field	Value
Publication number	US-2016215817-A1
Application number	US-201314653492-A
Country	US
Kind code	A1
Filing date	Dec 17, 2013
Priority date	Dec 21, 2012
Publication date	Jul 28, 2016
Grant date	—

Abstract

A magnetic bearing comprising a stator magnetic circuit secured to a stationary support device, the stator magnetic circuit comprising at least one coil and a ferromagnetic body placed in a protective annular support, the protective annular support leaving uncovered a surface of the ferromagnetic body and a surface of the at least one coil. The bearing also comprises at least one annular plug placed on the surface of the at least one coil which is left uncovered by the protective annular support, and the annular plug and the surface of the ferromagnetic body which is left uncovered by the protective annular support are coated by a protective layer.

First claim

What is claimed is:

1 . A magnetic bearing for a rotary machine having a rotor, the bearing comprising:
a stator magnetic circuit secured to a stationary support device, the stator magnetic circuit comprising at least one coil and a ferromagnetic body placed in a protective annular support, the protective annular support leaving uncovered a surface of the ferromagnetic body and a surface of the at least one coil; and at least one annular plug placed on the surface of the at least one coil which is left uncovered by the protective annular support, wherein the annular plug and the surface of the ferromagnetic body which is left uncovered by the protective annular support are coated by a protective layer.

2 . The bearing according to claim 1 , wherein the protective layer comprises a layer of nickel.

3 . The bearing according to claim 2 , wherein the layer of nickel is formed by electroless-nickel plating.

4 . The bearing according to claim 2 , wherein the layer of nickel comprises nickel and phosphorus.

5 . The bearing according to claim 1 , wherein the at least one annular plug comprises magnetic material selected from the group consisting of ferromagnetic material, magnetic stainless steel, and nickel base alloy.

6 . The bearing according to claim 1 , wherein the bearing is an axial magnetic bearing.

7 . The bearing according to claim 1 , further comprising a rotor armature in the form of a disk secured to the rotor, and wherein the stator magnetic circuit is facing the rotor armature.

8 . The bearing according to claim 7 , wherein the rotor and the rotor armature are, in use, in contact with a fluid, for instance a gaseous atmosphere, that is corrosive, acid, or carrying particles.

9 . The bearing according to claim 1 , wherein the at least one annular plug is brazed to the at least one coil, for instance by low temperature brazing.

10 . The bearing according to claim 1 , wherein the at least one annular plug has a U section with an radial web and two axial flanges.

11 . A rotary machine, comprising:
a rotor; and a bearing comprising:
a stator magnetic circuit secured to a stationary support device, the stator magnetic circuit comprising at least one coil and a ferromagnetic body placed in a protective annular support, the protective annular support leaving uncovered a surface of the ferromagnetic body and a surface of the at least one coil; and
at least one annular plug placed on the surface of the at least one coil which is left uncovered by the protective annular support, wherein the annular plug and the surface of the ferromagnetic body which is left uncovered by the protective annular support are coated by a protective layer.

12 . A method for manufacturing a bearing comprising a stator magnetic circuit secured to a stationary support device, the stator magnetic circuit comprising at least one coil and a ferromagnetic body placed in a protective annular support, the protective annular support leaving uncovered a surface of the ferromagnetic body and a surface of the at least one coil, the method comprising:
a) welding at least one annular plug to the at least one coil and/or to the ferromagnetic body; and b) coating the at least one annular plug and the surface of the ferromagnetic body which is left uncovered by the protective annular support with the protective layer.

13 . The method according to claim 12 , further comprising, between the steps a) and b), re-machining the at least one annular plug and the surface of the ferromagnetic body which is left uncovered by the protective annular support to get a flat surface.

14 . The bearing according to claim 3 , wherein the layer of nickel comprises nickel and phosphorus.

15 . The bearing according to claim 14 , wherein the at least one annular plug comprises magnetic material selected from the group consisting of ferromagnetic material, magnetic stainless steel, and nickel base alloy.

16 . The bearing according to claim 15 , wherein the bearing is an axial magnetic bearing.

17 . The bearing according to claim 16 , further comprising a rotor armature in the form of a disk secured to the rotor, and wherein the stator magnetic circuit is facing the rotor armature.

18 . The bearing according to claim 17 , wherein the rotor and the rotor armature are, in use, in contact with a fluid, for instance a gaseous atmosphere, that is corrosive, acid, or carrying particles.

19 . The bearing according to claim 18 , wherein the at least one annular plug is brazed to the at least one coil, for instance by low temperature brazing.

20 . The bearing according to claim 19 , wherein the at least one annular plug has a U section with an radial web and two axial flanges.

Assignees

• Nuovo Pignone Srl

Inventors

• Mei Luciano
• Fioravanti Duccio
• Romanelli Marco
• Anselmi Marco
• Bigi Manuele

Classifications

• H02K15/02

  of stator or rotor bodies · CPC title

• H02K7/09

  with magnetic bearings · CPC title

• F16C32/0476

  with active support of one degree of freedom, e.g. axial magnetic bearings · CPC title

• F16C32/047 Primary

  Details of housings; Mounting of active magnetic bearings · CPC title

• H02K3/44

  Protection against moisture or chemical attack; Windings specially adapted for operation in liquid or gas · CPC title