CA1149852A - Ferro-fluid bearing - Google Patents
Ferro-fluid bearingInfo
- Publication number
- CA1149852A CA1149852A CA000356348A CA356348A CA1149852A CA 1149852 A CA1149852 A CA 1149852A CA 000356348 A CA000356348 A CA 000356348A CA 356348 A CA356348 A CA 356348A CA 1149852 A CA1149852 A CA 1149852A
- Authority
- CA
- Canada
- Prior art keywords
- bore
- shaft
- axis
- recited
- entire
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
- H01F41/0273—Imparting anisotropy
- H01F41/028—Radial anisotropy
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
- F16C33/02—Parts of sliding-contact bearings
- F16C33/04—Brasses; Bushes; Linings
- F16C33/06—Sliding surface mainly made of metal
- F16C33/10—Construction relative to lubrication
- F16C33/1025—Construction relative to lubrication with liquid, e.g. oil, as lubricant
- F16C33/103—Construction relative to lubrication with liquid, e.g. oil, as lubricant retained in or near the bearing
- F16C33/1035—Construction relative to lubrication with liquid, e.g. oil, as lubricant retained in or near the bearing by a magnetic field acting on a magnetic liquid
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
- F16C33/72—Sealings
- F16C33/74—Sealings of sliding-contact bearings
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F7/00—Magnets
- H01F7/02—Permanent magnets [PM]
- H01F7/0231—Magnetic circuits with PM for power or force generation
- H01F7/0236—Magnetic suspension or levitation
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Magnetic Bearings And Hydrostatic Bearings (AREA)
Abstract
FERRO-FLUID BEARING
ABSTRACT OF THE DISCLOSURE
A bearing having a cylindrical bore and a shaft in the bore with ferrofluid between the shaft and the bore walls. The cylindrical bearing is made of ferromagnetic material, and it is magnetized with its internal magnetiza-tion radially directed relative to the axis of the bore.
Also pertains to a method for making and magnetizing the bearing.
ABSTRACT OF THE DISCLOSURE
A bearing having a cylindrical bore and a shaft in the bore with ferrofluid between the shaft and the bore walls. The cylindrical bearing is made of ferromagnetic material, and it is magnetized with its internal magnetiza-tion radially directed relative to the axis of the bore.
Also pertains to a method for making and magnetizing the bearing.
Description
~1~9~3~;Z
FEl~O-FLIJID ~EARI~G
B~Cl~GROUND OF THE I~r~TEN'rI0~
In recent years, bearing assemb:L:ies such as those dlsclssed in United States I.etters Patent.s Nos.
3,726.574, 3,746,407, 3,8~1,2&2 and 3,91~,773 'nave selr-contail-led fluid PO(J1S~ 'ihose l?atent:.s are ~s~i~ned to the same assi~nee as the present invention. Such fluidic, low frictlon sel,-contained bearlngs are made ~; possi~le by the develop,-nent of magnetically responsive : .
mag-netizable fluid given the name ferrofluid by i-ts d~veloper,-Dr. Ronald-E Rosens~eig. Ferrofluid is ~escribed in Rosensweig's "Progress in l~errohydrodyna.mics,"
industrial ~esealch, ~ctober, 1970, Vo3. 12, No. 1~, 36~40. Ferrofluid as defined therein is a dispersion of colloi~al magnetic pa.rticles in a liquid carrier~ These par~icles tend to align the.mselves with applied magnetic fiel~s. ~-t should be noted from the descri.ption of ferro--fluid that ferrofluid n~ed not necessarily contain iron or ferrous-t~e meta.l.. It is onIy necessary, for a fluid to be so-called, that the fluid be magneti~,able or capable ~2-~9~35~
Of being influenced by magnetic fields. The term "magne-tic fluid" is used interchangeably herein with the term "ferrofluid".
~ he bearings described in the above-iden-tified letters patent each concentrate the magnetic field at particular axial positions along the shaft to produce a seal for the ferro~luid. Typically vanes, or the like, are used to distribute ferrofluid on the bearing surface to maintain a sufficient fluid thickness to support or lubricate the bearing.
More recently the assignee has obtained United States Patent Number 4,254,961 issued March 10, 1981 for a "Seal for a Fluid Bearing". The bearing shown and des-cribed in that patent also concentrates the magnetic field at the seal points, but the structure may be modified according to this invention.
BRIEF DESCRIPTION OF T~IE INVENTION
The ferrofluid bearing of this invention uses a magnetic sleeve as a bearing for a shaft. The magnetic sleeve is a permanent magnet which produces a magnetic field, having both radial and axial components, between the bearing and the shaft. The axial'components are directed inwardly toward the center of the bearing, and Pg/-` ~ 3 ~
. . ~. "~
, : .: ~
9~5Z
the ferrofluid is held within the bearillg. I,'he op~os:ing surfaces of the shaft ancl be~ring mdy he contoured or smooth a-t the opt:ion of the desiyner.
To produce the desired magnet-ic Eield configura-tion, the bear;llg sleeve is maynetized with the pole faceson the oute~ and inner surfaces of the sleeve instead of the usual practice of placing the poles on the encls of the cylinder. The internal magnetization of the slee~e is -radially di^ected.
To produce d cylindrical sleeve having a high intensity magnetic field in a small volume and having- the pole fa~es on the outer-and inner su:faces, the sleeve may~
be made oE platinum cobalt alloy or rare earth cobalt a:Ll.o~s such as samarium cobalt alloys. Other pe~lanent magnet materials may be used, however, at considerably lower flu~
fields.
The sleeve is either fabricated in axial slices or is cut into axial slices. The slices are each magnetized by placing them into an eIectromagnetic field which is poled-to induce permanent magnet pole positions on the ou~er and inner surface of the slices. The slices are t~len assembled or reassembled into a cylindrical sleeve.
The shaft mav be either ferLomagnetic or non-~erromagnetic. In a typicaL embodiment the shaft may 2S ha~.Je a thin layer of ferromaynetic material on its outer . . .
~,' : . , .: . : -: :
~ ' ' ' ~ ' .. : - ' , ' . : ' :
:.
, , .. .
z surface. If t~e shaft has ferromagnet.ic materi.a.l., the operation is enhanced by the incl-ease in magnetic field intensity wi-th:in the r~gion between the shaft and be~ring It is there-Eore an object of this inventi.~n to teach a new ferrofluid bearillg.
It is another o~ject of this invention to teacll a method for fabr:icating a hollow cylindrical magnet with its pole faces on the inner and outer surfaces thereol.
-~RIEF DFSCRIPTION OF THE D~AWINGS
G-ther objects will become apparen-t fror,l the follo~7in~ descrip-tion, taken in connec-ti.on with the accompanying drawings, in which:
E`igure 1 is a profile view of a bearing and shaft according -to this invention, Figure 2 is an end view of the apparatus of Figure 1, .
Figure-3 is a sectional view taken at 3-3 in Fig-ure 2 and diagramming the magnetic field of the ~ -cylindrical magnet, and : 20 Figure 4 is a profile view of a typical electro- :
magnet magnetizing an axial slice o-f a cylindrical sleeve : to produce pole faces on the inner and outer surface of an assem~led cylinder.
. :
.. .
:. - , , : : .:: .: .:. .
85;2 DET~ILED ~ESCRIl'q'~:C)N 0~ THE` ~N~7ENTIOI~
The ferroEluid bearinc3 of this lnvention use~s a permaneLIt magne~ bearing structure 10 which preferably has a gerlerally circularly cylindrical shapeO The apparatus is nGt limited, howe~er, to a circular shape.
The structure 10 i5 shown as a right circular .
c~ylincler having a coaxial rigl~t circular cylindrical bore -therein fo-^ receiving a shaft 12 and a space containincJ
ferrofluid 14 therebetween. The ferrofluid 14 ser~es as a lubricant between the shaft ]~ and the surace 18 o tne bore 20.
r~he bearing 10 and shaft 12 may rotate relative to each other, but it is not important which rotates.
Both may rotate if desired.
The bearing 10 is magnetized with a polarlty configuration ~herein the pole faces are on the outer surface 16 and the irmer surface 18 -thereof. Such polarity configuration produces a magnetic field having both radial and a~ial components within the ferrofluid 14, and the a~ial components are directed toward the center of the bearin~ bore 20. The magnetic field is indicated at 24 in Figul^e 3. The magnetic field holds the ferro-fluid 14 wit11in the bore 20.
Tl-le shaft 12 may be of ferromagnetic material which erihances~t.he ma-~netic field intensity in the ferro-fluid 1~. It need not, however, be of such ferromagnetic , -6-., - ;~
1:
. .
- . . . -.. : :: : .
~985Z
mater:ial. IJ-I one prefexred emboclirne7l-~, only the sur~ace oL th~ sha-'t is cover~d with ferro,ma~ne-t:ic materi.al.
Mos-t of the bearing support occurs near the ends of the bore 2C. To reduce power loss due to viscous d~mping, -~hc cliamet~r oF the .slla:Et 12 optionally may be reduced near the center of the bore 20 in the region 22.
To magnetize cylindrical member 10, the member 10 is axially sliced into slices lOa,lOb, lOc, lOd, lOe, lOf, lOg, lOh, and disassembled ~or magnetizing.
Alternatively, the slices lOa, lOb, lOc, lOd, lOe, lOf, 10~, and lOh, may be fabricated into the shape shown in E'igure 4.~ For ~xample, .he slices may be cast or forged, or they may be made by powder metall~rgy tec~miques.
-. A~ter the slices lOa, lOb, lOc, lOd, lOe, lOfp lOg, lOht have-been magnetized, they are assembled or reassembled into the cylinder shown in Figures 1 and 2~
To magnetize the slices they are placed in the field of an electromagnet whi.ch induces a permanent ntagnetism into the slice lOa with the pole faces on the inner and outer surfaces 28, 29. The electromagnet 30 is shown with one coil turn, but obviously it may include :
many more turns to produce the requited field intensity.
The e.lectromagnet 30 is energized, for example, ~rom a DC en`ergy source 32.
~. .
' ' ' ~ ' The bearillg of this inventiorl, because of a radially d;rected internal magnetiza-tion, is a simplified bearing ~hich adeqllately confines the ferroEluid without leakin~.
Althou~l a d~scrip~ion of a typical apparatu3 - and method of this invention is sho~ in the Fi~ures and described above, it is not intended that the invention shall be limited by that description alone, but only together with the accompanying claims.
What is claimed is:
, ., -,
FEl~O-FLIJID ~EARI~G
B~Cl~GROUND OF THE I~r~TEN'rI0~
In recent years, bearing assemb:L:ies such as those dlsclssed in United States I.etters Patent.s Nos.
3,726.574, 3,746,407, 3,8~1,2&2 and 3,91~,773 'nave selr-contail-led fluid PO(J1S~ 'ihose l?atent:.s are ~s~i~ned to the same assi~nee as the present invention. Such fluidic, low frictlon sel,-contained bearlngs are made ~; possi~le by the develop,-nent of magnetically responsive : .
mag-netizable fluid given the name ferrofluid by i-ts d~veloper,-Dr. Ronald-E Rosens~eig. Ferrofluid is ~escribed in Rosensweig's "Progress in l~errohydrodyna.mics,"
industrial ~esealch, ~ctober, 1970, Vo3. 12, No. 1~, 36~40. Ferrofluid as defined therein is a dispersion of colloi~al magnetic pa.rticles in a liquid carrier~ These par~icles tend to align the.mselves with applied magnetic fiel~s. ~-t should be noted from the descri.ption of ferro--fluid that ferrofluid n~ed not necessarily contain iron or ferrous-t~e meta.l.. It is onIy necessary, for a fluid to be so-called, that the fluid be magneti~,able or capable ~2-~9~35~
Of being influenced by magnetic fields. The term "magne-tic fluid" is used interchangeably herein with the term "ferrofluid".
~ he bearings described in the above-iden-tified letters patent each concentrate the magnetic field at particular axial positions along the shaft to produce a seal for the ferro~luid. Typically vanes, or the like, are used to distribute ferrofluid on the bearing surface to maintain a sufficient fluid thickness to support or lubricate the bearing.
More recently the assignee has obtained United States Patent Number 4,254,961 issued March 10, 1981 for a "Seal for a Fluid Bearing". The bearing shown and des-cribed in that patent also concentrates the magnetic field at the seal points, but the structure may be modified according to this invention.
BRIEF DESCRIPTION OF T~IE INVENTION
The ferrofluid bearing of this invention uses a magnetic sleeve as a bearing for a shaft. The magnetic sleeve is a permanent magnet which produces a magnetic field, having both radial and axial components, between the bearing and the shaft. The axial'components are directed inwardly toward the center of the bearing, and Pg/-` ~ 3 ~
. . ~. "~
, : .: ~
9~5Z
the ferrofluid is held within the bearillg. I,'he op~os:ing surfaces of the shaft ancl be~ring mdy he contoured or smooth a-t the opt:ion of the desiyner.
To produce the desired magnet-ic Eield configura-tion, the bear;llg sleeve is maynetized with the pole faceson the oute~ and inner surfaces of the sleeve instead of the usual practice of placing the poles on the encls of the cylinder. The internal magnetization of the slee~e is -radially di^ected.
To produce d cylindrical sleeve having a high intensity magnetic field in a small volume and having- the pole fa~es on the outer-and inner su:faces, the sleeve may~
be made oE platinum cobalt alloy or rare earth cobalt a:Ll.o~s such as samarium cobalt alloys. Other pe~lanent magnet materials may be used, however, at considerably lower flu~
fields.
The sleeve is either fabricated in axial slices or is cut into axial slices. The slices are each magnetized by placing them into an eIectromagnetic field which is poled-to induce permanent magnet pole positions on the ou~er and inner surface of the slices. The slices are t~len assembled or reassembled into a cylindrical sleeve.
The shaft mav be either ferLomagnetic or non-~erromagnetic. In a typicaL embodiment the shaft may 2S ha~.Je a thin layer of ferromaynetic material on its outer . . .
~,' : . , .: . : -: :
~ ' ' ' ~ ' .. : - ' , ' . : ' :
:.
, , .. .
z surface. If t~e shaft has ferromagnet.ic materi.a.l., the operation is enhanced by the incl-ease in magnetic field intensity wi-th:in the r~gion between the shaft and be~ring It is there-Eore an object of this inventi.~n to teach a new ferrofluid bearillg.
It is another o~ject of this invention to teacll a method for fabr:icating a hollow cylindrical magnet with its pole faces on the inner and outer surfaces thereol.
-~RIEF DFSCRIPTION OF THE D~AWINGS
G-ther objects will become apparen-t fror,l the follo~7in~ descrip-tion, taken in connec-ti.on with the accompanying drawings, in which:
E`igure 1 is a profile view of a bearing and shaft according -to this invention, Figure 2 is an end view of the apparatus of Figure 1, .
Figure-3 is a sectional view taken at 3-3 in Fig-ure 2 and diagramming the magnetic field of the ~ -cylindrical magnet, and : 20 Figure 4 is a profile view of a typical electro- :
magnet magnetizing an axial slice o-f a cylindrical sleeve : to produce pole faces on the inner and outer surface of an assem~led cylinder.
. :
.. .
:. - , , : : .:: .: .:. .
85;2 DET~ILED ~ESCRIl'q'~:C)N 0~ THE` ~N~7ENTIOI~
The ferroEluid bearinc3 of this lnvention use~s a permaneLIt magne~ bearing structure 10 which preferably has a gerlerally circularly cylindrical shapeO The apparatus is nGt limited, howe~er, to a circular shape.
The structure 10 i5 shown as a right circular .
c~ylincler having a coaxial rigl~t circular cylindrical bore -therein fo-^ receiving a shaft 12 and a space containincJ
ferrofluid 14 therebetween. The ferrofluid 14 ser~es as a lubricant between the shaft ]~ and the surace 18 o tne bore 20.
r~he bearing 10 and shaft 12 may rotate relative to each other, but it is not important which rotates.
Both may rotate if desired.
The bearing 10 is magnetized with a polarlty configuration ~herein the pole faces are on the outer surface 16 and the irmer surface 18 -thereof. Such polarity configuration produces a magnetic field having both radial and a~ial components within the ferrofluid 14, and the a~ial components are directed toward the center of the bearin~ bore 20. The magnetic field is indicated at 24 in Figul^e 3. The magnetic field holds the ferro-fluid 14 wit11in the bore 20.
Tl-le shaft 12 may be of ferromagnetic material which erihances~t.he ma-~netic field intensity in the ferro-fluid 1~. It need not, however, be of such ferromagnetic , -6-., - ;~
1:
. .
- . . . -.. : :: : .
~985Z
mater:ial. IJ-I one prefexred emboclirne7l-~, only the sur~ace oL th~ sha-'t is cover~d with ferro,ma~ne-t:ic materi.al.
Mos-t of the bearing support occurs near the ends of the bore 2C. To reduce power loss due to viscous d~mping, -~hc cliamet~r oF the .slla:Et 12 optionally may be reduced near the center of the bore 20 in the region 22.
To magnetize cylindrical member 10, the member 10 is axially sliced into slices lOa,lOb, lOc, lOd, lOe, lOf, lOg, lOh, and disassembled ~or magnetizing.
Alternatively, the slices lOa, lOb, lOc, lOd, lOe, lOf, 10~, and lOh, may be fabricated into the shape shown in E'igure 4.~ For ~xample, .he slices may be cast or forged, or they may be made by powder metall~rgy tec~miques.
-. A~ter the slices lOa, lOb, lOc, lOd, lOe, lOfp lOg, lOht have-been magnetized, they are assembled or reassembled into the cylinder shown in Figures 1 and 2~
To magnetize the slices they are placed in the field of an electromagnet whi.ch induces a permanent ntagnetism into the slice lOa with the pole faces on the inner and outer surfaces 28, 29. The electromagnet 30 is shown with one coil turn, but obviously it may include :
many more turns to produce the requited field intensity.
The e.lectromagnet 30 is energized, for example, ~rom a DC en`ergy source 32.
~. .
' ' ' ~ ' The bearillg of this inventiorl, because of a radially d;rected internal magnetiza-tion, is a simplified bearing ~hich adeqllately confines the ferroEluid without leakin~.
Althou~l a d~scrip~ion of a typical apparatu3 - and method of this invention is sho~ in the Fi~ures and described above, it is not intended that the invention shall be limited by that description alone, but only together with the accompanying claims.
What is claimed is:
, ., -,
Claims (12)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A ferro-fluid bearing for supporting a circularly cylindrical shaft comprising:
a circularly cylindrical shaft;
a magnetic bearing structure forming a circular cylindrical bore surrounding said shaft, the diameter of said circularly cylindrical bore being larger than the outer diameter of said shaft, said bearing structure having the same poled radially directed internal magnetization along its entire length and around its entire circumference so there exists at substantially all regions of the surface of said bore the same pole face producing radially directed magnetic flux at said pole face and thence into the region between said pole face and said shaft;
A ferro-fluid between the surface of said bore of said bearing structure and said shaft.
a circularly cylindrical shaft;
a magnetic bearing structure forming a circular cylindrical bore surrounding said shaft, the diameter of said circularly cylindrical bore being larger than the outer diameter of said shaft, said bearing structure having the same poled radially directed internal magnetization along its entire length and around its entire circumference so there exists at substantially all regions of the surface of said bore the same pole face producing radially directed magnetic flux at said pole face and thence into the region between said pole face and said shaft;
A ferro-fluid between the surface of said bore of said bearing structure and said shaft.
2. Apparatus as recited in claim 1 in which said bear-ing structure is magnetized with a first one of the pole faces on the outside surface of said structure and the second pole face on substantially all regions along the entire length and around the entire circumference of the surface of said bore.
3. Apparatus as recited in claim 1 in which said bearing structure is fabricated of platinum cobalt alloy, and said shaft is fabricated with at least its surface of ferromagnetic material.
4. Apparatus as recited in claim 1 in which said bear-ing structure is fabricated of rare earth cobalt alloys, and said shaft is fabricated with at least its surface of ferro-magnetic material.
5. Apparatus as recited in claim 1 in which said bearing structure is fabricated of samarium cobalt alloys, and said shaft is fabricated with at least its surface of ferromagnetic material.
6. Apparatus as recited in claim 1 in which said bearing structure is divided into contacting attached axial slices from one end to the other by radial planes extending from and including the axis of said bore.
7. A process for fabricating a permanent magnet structure having a circularly cylindrical bore having the same polarity of internal magnetization, along the entire length and around the entire circumference of said bore, directed radially relative to the axis of said bore to produce the same pole face over substantially the entire surface of said bore comprising:
fabricating slices of said structure;
magnetizing each said slice by placing it in an electromagnetic field which is directed perpendicular to the surface of the portion of the bore on that said slice with the polarity the same on each said slice; and assembling said magnetized slices into contact on their radially directed surfaces to form said structure.
fabricating slices of said structure;
magnetizing each said slice by placing it in an electromagnetic field which is directed perpendicular to the surface of the portion of the bore on that said slice with the polarity the same on each said slice; and assembling said magnetized slices into contact on their radially directed surfaces to form said structure.
8. A process for magnetizing a permanent magnet structure having a circularly cylindrical bore which is adapted to receive a shaft comprising:
slicing said bearing structure in planes defined by radii and the axis of said bore;
magnetizing each said slice along its entire length by placing it in an electromagnetic field which is directed perpendicular to substantially the entire surface of the bore on that said slice with the polarity of magneti-zation the same on each said slice; and reassembling said magnetized slices into contact on their radially directed surfaces to reform said bearing structure.
slicing said bearing structure in planes defined by radii and the axis of said bore;
magnetizing each said slice along its entire length by placing it in an electromagnetic field which is directed perpendicular to substantially the entire surface of the bore on that said slice with the polarity of magneti-zation the same on each said slice; and reassembling said magnetized slices into contact on their radially directed surfaces to reform said bearing structure.
9. A permanent magnet comprising:
a permanent magnetic structure having a circularly cylindrical bore therethrough, said bore having an axis of symmetry;
said structure being divided circumferentially of said bore into a plurality of substantially contacting circum-ferential segments each having an inner surface which is a circumferential segment of the cylindrical surface of said bore;
all of said segments being magnetized along their entire length and about their entire portions of said circum-ference with their internal magnetizations identically poled in a radial direction relative to said axis to cause substan-tially the entire surface of said circumferential segments of said bore to become identically poled magnetic pole faces of said segments.
a permanent magnetic structure having a circularly cylindrical bore therethrough, said bore having an axis of symmetry;
said structure being divided circumferentially of said bore into a plurality of substantially contacting circum-ferential segments each having an inner surface which is a circumferential segment of the cylindrical surface of said bore;
all of said segments being magnetized along their entire length and about their entire portions of said circum-ference with their internal magnetizations identically poled in a radial direction relative to said axis to cause substan-tially the entire surface of said circumferential segments of said bore to become identically poled magnetic pole faces of said segments.
10. A permanent magnet as recited in claim 9 wherein said structure is divided between said segments substantially by planes defined by radii from said axis and by said axis.
11. A permanent magnet as recited in claim 9 wherein the outer surface of said magnet structure is substantially circularly cylindrical.
12. A permanent magnet as recited in claim 11 wherein said outer and inner surfaces are substantially concentric about said axis, and the internal magnetizations of said segments are identically poled and radial of said axis to cause said entire inner cylindrical surface of said structure to be a different polarity magnetic pole piece of said magnet than the magnetic polarity of said outer cylindrical surface.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US6219779A | 1979-07-30 | 1979-07-30 | |
| US62,197 | 1979-07-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1149852A true CA1149852A (en) | 1983-07-12 |
Family
ID=22040823
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000356348A Expired CA1149852A (en) | 1979-07-30 | 1980-07-16 | Ferro-fluid bearing |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5642722A (en) |
| CA (1) | CA1149852A (en) |
| DE (1) | DE3028454A1 (en) |
| FR (1) | FR2467318A1 (en) |
| GB (2) | GB2058953B (en) |
| IL (1) | IL60597A0 (en) |
| IT (1) | IT1128663B (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL8602343A (en) * | 1986-09-16 | 1988-04-18 | Skf Ind Trading & Dev | BEARING ASSEMBLY. |
| GB2222679B (en) * | 1988-03-15 | 1991-10-16 | Baroid Technology Inc | Accelerometers |
| JPH04313748A (en) * | 1991-01-23 | 1992-11-05 | Konica Corp | Photographic unit |
| JP2599459Y2 (en) * | 1991-03-15 | 1999-09-06 | エヌオーケー株式会社 | Magnetic fluid bearing |
| DE59205445D1 (en) * | 1991-07-11 | 1996-04-04 | Laube Hans Juergen | Magnetic body composed of several individual magnetic bodies and a permanent magnetic floating bearing with an overall magnetic body composed of several individual magnets |
| JPH0728599U (en) * | 1993-11-09 | 1995-05-30 | 株式会社プラスパ | Small chip stacking craft and chip materials |
| DE10244495A1 (en) * | 2002-09-25 | 2004-04-08 | Saurer Gmbh & Co. Kg | Textile machine with a variety of jobs |
| US9462388B2 (en) | 2004-06-03 | 2016-10-04 | Tymphany Hk Limited | Acoustic transducer comprising a plurality of coaxially arranged diaphragms |
| CA2567733A1 (en) * | 2004-06-03 | 2005-12-22 | Tymphany Corporation | Acoustic transducer comprising a plurality of coaxially arranged diaphragms |
| DE202005005904U1 (en) * | 2005-04-07 | 2006-08-17 | Ebm-Papst St. Georgen Gmbh & Co. Kg | Bearing arrangement for bearing of swiveling shaft has swiveling shaft of hard ferromagnetic material, which has a permanent magnetic field whereby plain bearing serves as return for magnetic field lines of permanent magnetic field |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1052192B (en) * | 1956-07-14 | 1959-03-05 | Philips Nv | Sealing for a shaft duct through the wall of a space containing fine iron particles |
| GB842531A (en) * | 1958-12-24 | 1960-07-27 | Mullard Ltd | Permanent magnets |
| DE2034213C3 (en) * | 1969-10-10 | 1985-04-25 | Ferrofluidics Corp., Burlington, Mass. | Magnetic seal for sealing sealing gaps |
| US3620584A (en) * | 1970-05-25 | 1971-11-16 | Ferrofluidics Corp | Magnetic fluid seals |
| US3726574A (en) * | 1971-08-13 | 1973-04-10 | Litton Systems Inc | Ferrohydrodynamic low-friction bearing with volume compensation |
| US3746407A (en) * | 1971-08-13 | 1973-07-17 | Litton Systems Inc | Ferrohydrodynamic low friction bearing |
| GB1413118A (en) * | 1972-12-08 | 1975-11-05 | Godsill J K | Lubrication |
| DE2213465C3 (en) * | 1972-03-20 | 1986-02-13 | Padana AG, Zug | Electromagnetic bearing element |
| USRE27955E (en) * | 1972-05-19 | 1974-04-02 | Bearing arrangement with magnetic fluid defining bearing pads | |
| DE2245039B2 (en) * | 1972-09-14 | 1976-01-02 | Daimler-Benz Ag, 7000 Stuttgart | bearings |
| US3918773A (en) * | 1974-01-07 | 1975-11-11 | Litton Systems Inc | Magnetic field responsive hydrodynamic bearing |
| DE2420825C3 (en) * | 1974-04-30 | 1980-04-17 | Padana Ag, Zug (Schweiz) | Magnetic bearing of a rotor |
| US4065188A (en) * | 1975-02-10 | 1977-12-27 | Strathearn Audio Limited | Linear bearing for parallel tracking arm |
| US4043612A (en) * | 1975-06-06 | 1977-08-23 | Ampex Corporation | Bearing structure |
-
1980
- 1980-07-15 IL IL60597A patent/IL60597A0/en unknown
- 1980-07-16 CA CA000356348A patent/CA1149852A/en not_active Expired
- 1980-07-24 GB GB8024332A patent/GB2058953B/en not_active Expired
- 1980-07-26 DE DE19803028454 patent/DE3028454A1/en not_active Withdrawn
- 1980-07-28 IT IT49355/80A patent/IT1128663B/en active
- 1980-07-29 FR FR8016694A patent/FR2467318A1/en active Granted
- 1980-07-30 JP JP10376080A patent/JPS5642722A/en active Pending
-
1982
- 1982-10-18 GB GB08229706A patent/GB2124033B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB2124033B (en) | 1984-08-01 |
| DE3028454A1 (en) | 1981-02-19 |
| FR2467318B1 (en) | 1984-08-10 |
| FR2467318A1 (en) | 1981-04-17 |
| IT1128663B (en) | 1986-06-04 |
| GB2058953A (en) | 1981-04-15 |
| GB2058953B (en) | 1983-05-05 |
| JPS5642722A (en) | 1981-04-21 |
| IT8049355A0 (en) | 1980-07-28 |
| GB2124033A (en) | 1984-02-08 |
| IL60597A0 (en) | 1980-09-16 |
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