CA1153414A - High speed magnetic coupling with ceramic magnets maintained under centrifugal compression - Google Patents

High speed magnetic coupling with ceramic magnets maintained under centrifugal compression

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Publication number
CA1153414A
CA1153414A CA000320332A CA320332A CA1153414A CA 1153414 A CA1153414 A CA 1153414A CA 000320332 A CA000320332 A CA 000320332A CA 320332 A CA320332 A CA 320332A CA 1153414 A CA1153414 A CA 1153414A
Authority
CA
Canada
Prior art keywords
magnetic
sleeve
driven
samarium
magnetic means
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
Application number
CA000320332A
Other languages
French (fr)
Inventor
Alexander Silver
Kenneth L. Wuertz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Garrett Corp
Original Assignee
Garrett Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Garrett Corp filed Critical Garrett Corp
Application granted granted Critical
Publication of CA1153414A publication Critical patent/CA1153414A/en
Expired legal-status Critical Current

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Classifications

    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K49/00Dynamo-electric clutches; Dynamo-electric brakes
    • H02K49/10Dynamo-electric clutches; Dynamo-electric brakes of the permanent-magnet type
    • H02K49/104Magnetic couplings consisting of only two coaxial rotary elements, i.e. the driving element and the driven element
    • H02K49/106Magnetic couplings consisting of only two coaxial rotary elements, i.e. the driving element and the driven element with a radial air gap
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D13/00Pumping installations or systems
    • F04D13/02Units comprising pumps and their driving means
    • F04D13/021Units comprising pumps and their driving means containing a coupling
    • F04D13/024Units comprising pumps and their driving means containing a coupling a magnetic coupling
    • F04D13/027Details of the magnetic circuit
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D25/00Pumping installations or systems
    • F04D25/02Units comprising pumps and their driving means
    • F04D25/026Units comprising pumps and their driving means with a magnetic coupling
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04DNON-POSITIVE-DISPLACEMENT PUMPS
    • F04D25/00Pumping installations or systems
    • F04D25/02Units comprising pumps and their driving means
    • F04D25/04Units comprising pumps and their driving means the pump being fluid-driven
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K5/00Casings; Enclosures; Supports
    • H02K5/04Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/12Casings or enclosures characterised by the shape, form or construction thereof specially adapted for operating in liquid or gas
    • H02K5/128Casings or enclosures characterised by the shape, form or construction thereof specially adapted for operating in liquid or gas using air-gap sleeves or air-gap discs

Abstract

ABSTRACT OF THE DISCLOSURE

A high speed permanent magnet coupling is disclosed com-prising a generally cup-shaped outer coupling member rotatably driven by a suitable driving source and concentrically received over an inner coupling member, the two coupling members being separated by a hermetically sealing wall or barrier. The outer and inner coupling members each include a plurality of axially elongated permanent magnets surrounded by the respective coupling members to hold the magnets in centrifugal compression during rotation.

Description

HIGH SPEED MAGNETIC COUPLING

BACKGROUND OF THE INVENTION

This invention relates to permanent magnet couplingsO More specifically, this invention relates to a high strength permanent magnet coupling including samarium-cobalt magnets and mounting methods therefor.

Permanent magnet couplings are well known in the prior art, and typically comprise a pair of axially or radially opposed magnets or sets of magnets formed from a permanent magnet material, such as alnico. One of the permanent magnets is coupled to a driving member such as a motor, and the other permanent magnet is coupled to a driven member such as a pump impeller. The magnets are magnetically coupled to each other such that rotation of the driving member causes a corresponding rotati`on of the driven member to obtain the desired torque output. Couplings of this type are particularly advantageous wherein a hermetic seal or barrier is interposed between the driving and driven members, such as in a motor-driven FREON*
compressor. In these applications, the hermetic seal assures * Trade Mark agains~ passage or le~kage of any proce~ fluid betwe~n the driving and driven members, and thereby prolong~ the operating life of the equipment. For examples of prior art magnetic coupling~, including hermetic seals or barrier6, see U. S. Patent 1'~o~.3~ 877~ B44; 3~ 826,938;
3,411,4~0; 3,512,903; 3,378,710; 3,249,777; 3,238,8~3; 3,Z3~,878;
3~ 195,4~7; 2~97û,548; 2~ 366,562; 2~2309717; and Reissue 26,094.
During operation, a magnetic coupling may generate sub6tantial quantities of heat due to relative slippage of the magnets at exces6ive torque loads, induction heating effects, and the like. This is 10 parti-~ularly true with closely aligned, radially interfitting permanent magnets rotating at relatively high speeds Ruch as on the order of about 100,000 rpm. Accordingly, pIior art magnetic couplings typically have not been used with mechanical devices rotating at relatively high speeds so as to avoid any cooling requirement. However, some attemp~s have 15 been made to cool a magnetic coupling, and have typically comprised methods of exposing at least a portion of one of the magnets to a cooling fluid. See, for example, U. S. Patent Nos. 3,238,883;
3~238,878; and 3~267~868. These prior art deYices have not, however, provided the requisite pumping or cooling action required with high 20 speed rotating maehinery such as turbonlachines.
Another problem in the design of magnetic couplings i6 the prevention of demagnetization due to coupling slippage a~ high 3peeds and/or high torque conditions. That i8~ with magnetic couplings, the maximum coupling torque available i8 limited to the magnetic 25 and ~tructural characteristic~ of the magnets. Typically, prior art 53~

permanent magnets con~tructed for ~tructural integrity at high speeds have not provided a magnetic field of sufficient strength for slippage-free coupling under high torque condition~. Some permanent magnet materials capable o~ providing such high torque coupling, ~uch as 5 rare earth-cobalt magnets, have not been sati6factorily used becau6e of structural brittleness. Specifically, a magnetic coupling ha~ not beer~ provided including high magnetic strength, ~tructurally brittle magnets wherein cracking or breaking of the magnets due to centrifugal force effects at high ~peeds i6 prevented.
Prior art magnetic couplings have also encountered bearing desi~n problems. That i8~ with low 6peed rotating devices, magnet-carrying shafts may be satisfactorily ~upported by relatively simple jo~lrnal and thrust bearing structures such as sleeve bearings, ball bearings, and the like. However, as rotational speed increases, 15 the problems of shaft stability and vibration correspondingly increase to create bearing de6ign and cooling problems. Moreover, with increased speed, the adverse effects on the 6ystem due to incidental bearing magnetization and induction heating becoIne substantial.
Nevertheless, the prior art has consistently relied upon relatively 20 conventional bearing structure6 for sha~t ~upport. See, for example, U.S. Patent Nos. 3,512,903; 3,378,710; 3,195,467; 3~238J878;
2~ 970, 548; and 2, 366, 562. Accordingly, permanent magnet couplings in the prior art have not been ~videly or sati~factorily used in high speed applications.
Thi~ invention overcome~ the problems and disadvantage~ of ~he prior art by providing an improved permanent magnet coupling particularly for use with relatively high speed rotating machinery. In particular, the invention includes relatively brittle, high magnetic strength samarium-cobalt permanent magnets mounted for structural integritv under high speed rotating conditions.

SUMMARY OF THE INVENTION
In accordance with one aspect of the invention, there is provided a magnetic coupling for coupling rotational motion through a sealed wall comprising rotatable driving means on one side of the sealed wall; first and second magnetically coupled magnetic means; Eirst means for mounting said first magnetic means on said driving means and for maintaining the same under centrifugal compression upon rotation of said driving means; rotatable driven means axially aligned with said driving means on the opposite side of the sealed wall;
and second means for mounting said second magnetic means on said driven means in magnetic coupling relation with said first magnetic means, and for maintaining said second magnetic ~0 means under centrifugal compression upon rotation of said driven means.
In accordance with another aspect of the invention, there is provided a method of manufacturing a magnetic coupling for magnetically coupling rotational motion through a sealed ~5 wall comprising the steps of providing rotatable driving means on one side of the wall; mounting first magnetic means on said driving means for maintaining said first magnetic means under centrifugal compression upon rotation; providing rotatable driven means on the opposite side of the wall axially aligned with the driving means; mounting second magnetic means magnetically coupled to the first magnetic means on said driven means for maintaining said second magnetic means under centrifugal compression upon rotation and in magnetic coupling relation with said first magnetic means.

-In accordance with the invention, a high speed permanent magnet coupling comprises a generally cup-shaped outer coupling member rotatably driven by a suitable driving source such as a motor. The outer coupling member is concentrically received over a projecting portion her-metically sealed wall or barrier configured for close reception within the outer coupling member without physical contact therewith. An inner coupling member is concen~
trically received within the projecting portion of the sealed wall and thereby also concentrically within the outer coupling member. The inner coupling member is coupled to a driven shaft for transmitting rotational movement through the hermetically sealed wall to a suitable driven source, such as a compressor impeller.
The outer and inner coupling members each include a plurality of axially elongated permanent magnets formed from a high strength rare earth-cobalt permanent magnet material such as samarium-cobalt. More specifically, the members each include a like number of magnets each having an arcuate cross section and circumferentially arranged within a cylindrical sleeve. The outer and inner sets of ma~nets are disposed for magnetic coupling with each other whereby, upon rotation of the outer coupling member, the inner coupling member correspondingly rotates. Importantly~ the sleeve~ of the outer and inner coupling members serve to maintain the ~et~ of magnet~ under compression during rotation to maintain the structural integrity of said magnets.
The cylindrical sleeves of the outer and inner coupling members 5 are each formed 6eparately from their re6pective driving or driven shaft. More 6pecifically, the sleeve on the outer coupling member i6 mounted exteriorly on the end of the driving ~haft a~ by a plurality of pres6-fit pin6, and the sleeve on the inner coupling member i6 centri-fugally retained by peripheral flange~ on the driven ~haft, and on an 10 end plug. With this construction, the 61eeves undergo 6ubstantially uniform thelrnal- and/or centrifugal expansion along their length6 when the coupling is rotated, 60 that the set6 of magnets are maintained under substantially uniform compression at all tune~.
The inner driven coupling member is carried in a region of a B Ff~,J ~
15 process fluid such as ~reor~, and includes a proce~s fluid flow path so that proces~ fluid may be circulated into clo6e proximity with the magnets to cool the ~ame during operation. More specifically, the driven ~haft includes axial and radial passages adapted for centrifugally pumping the process ~luid to cause circulatory flow adjacent ~he magnets. If desired, 20 the inner coupling member may be rotationally and axially ~upported by process fluid bearing~ such as foil bearings, di~po~ed in the proce6s fluid flow path whereby the beari~gs are cooled and lubrica~ed by the circulating fluid.
BRIEF DESCRIPTION OF THE DRAWINGS
25 The accompanying drawing~ illustrate the invention. In ~uch drawings.
~ t~ e tr)c,r~

Fig. 1 is a schematic illu~tration of a magnetic coupling;
Fig. 2 i6 a vertical ~ection of a permanent magnet coupling of this invention;
Fig. 3 i6 an enlarged fragmented vertical ~ection of a portion 5 of Fig. 2;
Fig.4 iB an enlarged fragmented vertical ~ection taken on the line 4-4 oi Fig. 3; ~
Fig. 5 is an enlarged fragmented vertical section taken on the line 5-5 OI Fig. 3; and Fig. 6 is an enlarged fragmented vertical section taken on the line 6-6 of Fig. 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
~ . _ A magnetic coupling 10 i6 shown generally in Fig. 1 comprising a generally cup-shaped outer driving member 12 coupled to one end of a 15 driving shaft 14 which is suitably driven rotatably by power source 16 such as a motor, engine, or the like. The cup-shaped driving member 12 is concentrically received over a projection 18 formed in an hermetically sealed wall 20 providing a barrier between components of the magnetic coupling. An ~nner driven member 22 i6 concentrically received 20 within the wall projection 18 opposite the driving member 12 and in magnetic coupling relationship therewith, whereby rotational movement of the drLving member 12 impart~ corresponding rotational movement to the driven member 22.` The driven member 22 rotatably drives a driven shaft 24 which~ in turn, drives a driven element 26 ruch F~bso/)l ~ ' ~B 25 as a Fe~ compres~or impeller. In thi~ manner~ the ct)mpreasor 26 ~- ~ r~ cl~

i6 rotatably drive~ by the power source 16 in a positive leak-free manner without the u~e o~ mechanical ~haft aeals or the like there-between.
A preferred system incorporating a permanent magnet coupling 10 5 of this invention i6 illulitrated in Figo 2~ illustrated, the power source 16 may include a turbine wheel 28 carried in a'turbine hou~ing 30 fo~; recei~ing hot exhaust gases from a suitable combu~tor of a power turbine or other motive source (not ~hown). The e~aust gasefi rotatably drive the turbine wheel 28 before discharging through an exhaust gas 10 outlet 32. The turbine wheel 28 couples high ~peed rotational movement via the driving shaft 14 to a compressor impeller 34. The compressor impeller 34 is suitably carried in a compressor housing 36, and rotation of the impeller 34 serves to draw air into the hou6ing 36 through an inlet 38 for compression and subsequent disch~rge to the air intake of the 15 power source combustor (not shown)~ all in a well Icnown manner.
The driving shaft 14 forming the common ~haft for the turbine wheel 28 and the compressor impeller 34 al60 forms the driving shaft for the magnetic coupling 10 of this invention. More speci~ically~ the driving shaft 14 extends from the impeller 34 toward the coupling 10, 20 and is connected as will be hereafter described in detail to the outer driving membes 12. The outer member 12 magnetically couples through the hermetically sealed wall 18 to the inner driven member 22 which i6 coupled as will be hereafter described to the driven shaft 24.
The driven ~haft 24 in turn connects to the driven element 26 comprising B ~ d i~' *
25 a ~ compre~60r impeller, uuitably carri~d in a region of a proces6 -~ t ~c~ c
3~ fluid such as ~-~eo~ in a f~ compres~or housing 40.
The magr~etic c:oupling IO i6 shown in more detail in Figs. 3 through 6. As shown, the driving shaft 14 terminates in a peripheral flange 42 projecting axially toward the projection 18 of the hermetically 5 sealed wall 20. A cylindrical sleeve 44 i8 concentrically and snugly received over flange 42, and projects from the flange 42 concentrically about the projecting portion 18 of the sealed wall 20. ThuR, the driving shaft 14 and the sleeve 44 together form the generally oup-shaped outer driving member 12. Importantly, the sleeve 44 is 10 secured to the 6haft flange 42 as by a plurality of circumferentially spaced pins 46 received in press-fit relation through a corresponding plural*y of aligned openings 48. In thi~ manner, upon rotation of the driving shaft 14, the sleeve 44 is able to expand radially as needed uniformly along its length to account for any effects due to thermal 15 and/or centrifugal expansion.
~ lurality of permanent magnets 50 are carried internally ~vithin the sleeve 44. In the preferred embodiment~ these permanent magnets 50 comprise a series of axially elongated permanent magnets formed from sa~narium-cobalt to have a relatively high magnetic ~trength. Each of 20 the magnets 50 has an arcuate crocs 6ection so as to form a circular series of magnetR when contained within the ~leeve 44, as shown in Fig. 4. If desired, a ~uitable gap filler material 52 may be interposed between adjacent magnets 50 to separate the magnets from each other and to assure proper anchoring within the ~leeve. O~ course~ while 25 8iX 0~ the magnets 50 are ~hown in the drawings~ it ~hould be urlderstood t ,~ r~
~ 8 --that the number of magnet6 i~ a cb~ice o~ design. I3nportantly, when the driving member 12 i~ rotated~ the magnets 50 are all retained under uni~orm compression by the sleeve 44.
The permanent magnets 50 within the sleeve 44 define an inner diamel:er ~or the driving member 12 sized or close reception over the projecting portion 18 of the he~netically ~ealed wall 20 without physical contact therewith. Importantly, the sealed wall 20 provides a barrier impervious to process fluid on either side thereof, and thereby allows a positive leak-free coupling of rotational motion. This sealed wall 20 10 may be formed from any of a wide variety of materials, such as stainless steel, or an electrically resistive material ~uch as a 6uitable ceramic. The thickness of the projecting portion 18 of the wall is determined by the structural rigidity necessary to withstand the operating pressures of process fluids, and by the radial spacing necessary lS between the outer and inner members 12 and 2Z for the desired magnetic torque coupling. lmportantly, with sa~narium-cobalt magnets, the wall portion 18 may be thicker than when prior art magnets such as alnico are used because of the higher magnetic ~trengthof samarium-cobalt magnets.
The driven member 22 is concentrically received within the projecting portion 18 of the hermetically sealed wall 20, and thereby also concentrically within the outer driving member 12~ ~he driven member 22 comprises a tubular exten~ion 54 of the driven sha~t 24 projecting into the wall portion 18. The tubular extension 54 bears 25 against an axially extending boss 56 fonned on the end of the driven J(~

shaft 24, and e2~tends therefrom into the wall portion 18 terminating near the axial extent of ~aid wall portion. A plurality o~ permanent magnets 58 each compri~ing an axially elongated magnet formed from samarium-cobalt are radially arranged about the tubular extension 54, 5 and are retained axially between the shaft bo~s 56 and an end plug 60 slidably received over the tubular exten6ion 54. I~nportantly, the magnets 58 each have an arcuate cros6 6ection to peripherally surround the tubular exten~ n 54~ and co~respond in number, length, and general magnetic properties to the magnets 50 carried on the outer 10 driving member 12. The magnets 58 and the end plug 60 are axially retained on the tubular extension 54 as by a nu~ 62 threadably received over the end of 6aid extension 54.
A peripheral sleeve 64 radially contains the permanent magnets 58 on the inner driven member 22. As ~hown, the aleeve 64 wraps around 15 the 6eries of magnets 58, and extends axially between the driven 6haft 24 and the end plug 60. The sleeve 64 i6 conveniently secured in position by receiving the ends thereof concentrically within the bounds of facing peripheral flanges 66 and 68 formed respectively on the driven 6haft 24 and the end plug 60. ~nportantly, the magnets 58 on the inner coupling 20 member 22 are positioned in close magnetic coupling relation with the magnet6 50 on the outer coupling member 12. In this manner, rotation of the outer magnets 50 cau~e~ a correRponding rotation of ~he inner magnets 58 without phy6ical contact with the ~ealed wall 20~ and thereby also rotates the driven shaft 24 and the driven element 26. The sleeve 64 25 radially restraining the inner magnets 58 maintains those magnets undes ~ubstantially uniform compre~sion during such rotation regardlea6 of ~3~

effects due to thermal and/or centrifugal expan~ion.
The pe~manent magne~ coupling lO of thi~ invention i9 readily adap~ed ~or u6e with process fluid bearing~. That i~, a~ ahown in the drawings, the driving shaft 14 includes a radially projecting 5 peripheral flange 70 received in an annular rece6s 72 formed between the power source compressor housing 36 and à housing 74 enclosing the outer driving member 12. Process fluid ~hrust bearings 76 and 78 are interposed between the faces of the flange 70 and adjacent housing surfaces to control axial sha~t movement. From the flange 70, the outer coupling member 12 extends toward the 6ealed wall within the housing 74. The sleeve 44 of the roupling member 12 is supported ~or smooth rotation by a series of process fluid journal bearings 80 carried within said housing 74. In the preferred embodiment, these process fluid thrust bearings 76 and 78 and 15 journal bearings 80 are hydrodynamic bearings of the foil bearing type disclosed and described in U.S.Patent Nos.3,215,480; 3,366,427;
3,375,046; 3,382,014; 3,434,762; 3,615,121; 3,6359534; 3,642,331;
3,677,612; 3,893,733; 3,951,474 and 3,957,317, all assigned to the assignee of this application. The specific construction and 20 mounting of these bearing6 is believed to be well documented by the referenced patents and therefore i6 not de~cribed in detail herein.
The driven shaft 24 i~ al~o de~irably ~upported for relatively high speed rotation by suitable proce~s fluid journal and thrust bearings. That is~ t~e driven shaft 24 include~ a radially projecting 2~ peripheral flange 82 received in an annular rece 8 84 defined by suitable housing members 86 and 88 provided ~c>r encl~sing the driven elemen~ 26. The opposed face~ of the flange 82 are separated from the adjacent hou~ing members by suitable proces~
fluid thrust bearings 90 and 9Z. Similarly, ~he driven shaft 24 i6 rotationally ~upported with respect to the housing member 88 by a series of suitable proces6 fluid journal bearing~ 94. Importantly, in the preferred embodiment, these proces6 fluid ~hrust bearings 90 and 92, and journal bearings 94 also comprise hydrodynamic bearings generally of the foil bearing type as disclo6ed and described in the above referenced U.S. patents.
As shown in Figs. 2 and 6, the driven member 22 and the driven shaft 24 include a process fluid flow path illustrated by arrows 91 for cooling the permanent magnets during operation.
Moreover, the process fluid bearings 90, 92, and 94 are conveniently disposed along the flow path 91 BO that the process fluid is also ~upplied to these bearings. More specifically, the flow path 91 is defined by a longitudinally extending bore 96 formed in the driven shaft 24 and communicating with a region of a proces6 fluid, ~uch B ~f.~
as ~ n, via a pair of outwardly radiating oppo~ed ports 98 formed in the shaft 24 between the hDusing member 88 and the driven element 26. The bore 96 extend~ through the shaft 24 and aligns with a passage 99 formed through the tubular exten~iDn 54 and communicating with the sealed wall portion 18. .In ~peration, upon rotation of the ~haft 24, the procesa fluid iB centrifugally pumped out of the bore 96 through t~e ports 98 into the proce3s r~; ~l e. n-~ r 1~
- 12 _ fluid region. This induces a process.fluid circulation through the bearings 94, 92, and 90, and further across the surfaces of the hermetically sealed wall portion 18 and the inner coupling member 22 into the bore 96 via the tubular extension passage 99.
In this manner, the process fluid bearings are effectively and continuously lubricated and cooled, and -the heat generated by the sets of magnets 50 and 58 is carried away by the process fluid to allow high speed coupling operation without overheating.

The permanent magnet coupling of this invention is operable under relatively high speed and high torque load conditions without adverse ~earing or heating problems. Moreover, the coupled sets of permanent magnets are maintained under sub-stantially uniform compressive forces during operation to maintain structural integrity of the magnets. Of course, various modifi-cations of the invention are possible, but are believed to bewithin the skill of the art and.thus contemplated by the descrip-tion herein. For example, if desired, circulation of a process fluid such as air or oil may be provided for the driving member 12 and the associated process fluid bearings 76, 78 and 80.

,~~

Claims (37)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A magnetic coupling for coupling rotational motion through a sealed wall comprising rotatable driving means on one side of the sealed wall; first and second magnetically coupled magnetic means; first means for mounting said first magnetic means on said driving means and for maintaining the same under centrifugal compression upon rotation of said driving means;
rotatable driven means axially aligned with said driving means on the opposite side of the sealed wall, and second means for mounting said second magnetic means on said driven means in magnetic coupling relation with said first magnetic means, and for maintaining said second magnetic means under centrifugal compression upon rotation of said driven means.
2. A magnetlc coupling as set forth in claim 1 wherein said first and second magnetic means comprise concentric magnets respectively mounted on said driving means and said driven means.
3. A magnetic coupling as set forth in claim 2 wherein said driving means, first magnetic means, and first means combine to form a generally cup-shaped outer driving member; and said driven means, second magnetic means, and second means combine to form an inner driven member concentrically received within said cup-shaped outer member, said sealed wall being configured to fit concentrically between said inner and outer members.
4. A magnetic coupling as set forth in claim 1 wherein at least one of said first and second magnetic means comprises at least one samarium-cobalt magnet.
5. A magnetic coupling as set forth in claims 1 or 4 wherein at least one of said magnetic means comprises a plurality of axially elongated magnets, and the associated mounting means comprises an axial sleeve internally carrying said magnets for maintaining said magnets under centrifugal compression during rotation.
6. A magnetic coupling as set forth in claim 1 wherein said first means comprises a first axial sleeve; said first magnetic means comprising a first plurality of axially extending magnets carried within said first sleeve circumferentially about the inner diameter of said first sleeve; said second means comprising a second axial sleeve disposed concentrically with respect to said first sleeve and first plurality of magnets;
and said second magnetic means comprising a second plurality of axially extending magnets carried within said second sleeve circumferentially about the inner diameter of said second sleeve.
7. A magnetic coupling as set forth in claim 1 wherein said first and second magnetic means each comprise a like number of magnets each including at least one samarium-cobalt magnet.
8. A magnetic coupling as set forth in claim 6 wherein said first and second pluralities of magnets each comprise a like number of magnets each including at least one samarium-cobalt magnet.
9. A magnetic coupling as set forth in claim 6 wherein said second axial sleeve is disposed concentrically within said first sleeve and first plurality of magnets.
10. A magnetic coupling as set forth in claim 6 wherein at least one of said first and second axial sleeves is received exteriorly over one end of the associated rotatable means, and including means for connecting said one of said sleeves to the associated one of said rotatable means.
11. A magnetic coupling as set forth in claim 10 wherein said one sleeve and the associated one of said rotatable means include aligned radial openings, and said connecting means comprises a plurality of circumferentially spaced pins received into said aligned openings.
12. A magnetic coupling as set forth in claim 10 wherein said first axial sleeve is received exteriorly over one end of said driving means, said driven means including a pair of peripheral flanges received concentrically over the opposite ends of said second axial sleeve for radially containing said second sleeve, said second sleeve being disposed concentrically within said first sleeve.
13. A magnetic coupling as set forth in claim 1 wherein one of said rotatable means is disposed within a region of a process fluid, and includes radially and axially extending passages for centrifugally establishing process fluid circulation over the magnetic means mounted thereon.
14. A magnetic coupling as set forth in claim 13 wherein said one of said rotatable means includes at least one outwardly radiating port disposed on the side of the associated magnetic means opposite the wall, and a longitudinally extending central bore communicating between the wall and the port whereby process fluid is centrifugally pumped upon rotation out of the bore through the port to cause fluid circulation over the associated magnetic means and into the bore.
15. A magnetic coupling as set forth in claim 13 wherein said second magnetic means is disposed concentrically within said first magnetic means, and said driven means comprises said one rotatable means.
16. A magnetic coupling as set forth in claim 14 including process fluid bearings for supporting said one rotatable means, said bearings being disposed between said port and the wall so that fluid is circulated through said bearings.
17. A magnetic coupling for coupling rotational motion through a sealed wall comprising rotatable driving means on one side of the sealed wall; first and second magnetically coupled samarium-cobalt magnetic means; first means for mounting said first samarium-cobalt magnetic means on said driving means and for maintaining the same under centrifugal compression upon ro-tation of said driving means; rotatable driven means axially aligned with said driving means on the opposite side of the sealed wall; and second means for mounting said second samarium-cobalt magnetic means on said driven means in magnetic coupling relation with said first samarium-cobalt magnetic means, and for maintain-ing said second samarium-cobalt magnetic means under centrifugal compression upon rotation of said driven means.
18. A magnetic coupling as set forth in claim 17 wherein said first means comprises a first axial sleeve received exter-iorly over one end of said driving means, and means for connect-ing said first sleeve to said driving means to allow relative radial expansion therebetween; said first samarium-cobalt mag-metic means comprising a first plurality of samarium-cobalt magnets radially contained within said first sleeve; said second means comprising a second axial sleeve having its opposite ends radially contained by facing peripheral flanges on said driven means; and said second samarium-cobalt magnetic means comprising a second plurality of samarium-cobalt magnets radially contained within said second sleeve and corresponding in number to the number of magnets of said first plurality, said second magnets and second sleeve being concentrically received within said first magnets and first sleeve.
19. A magnetic coupling for coupling rotational motion through a sealed wall comprising a rotatable driving shaft on one side of the wall; first and second magnetically coupled samarium-cobalt magnetic means; an axial first sleeve having one end received over one end of said driving shaft and radially containing said first samarium-cobalt magnetic means under centrifugal compression during rotation; connecting means for connecting said first sleeve to said driving shaft to allow relative radial movement therebetween; a rotatable driven shaft on the other side of said wall; and a second axial sleeve secured to said driven shaft and radially containing said second samarium-cobalt magnetic means under centrifugal compression during rotation, said first sleeve and first magnetic means being concentrically disposed with respect to said second sleeve and second magnetic means.
20. A magnetic coupling as set forth in claim 19 wherein said second sleeve and second magnetic means is disposed concent-rically within said first sleeve and first magnetic means.
21. A magnetic coupling as set forth in claim 18 or 20 wherein said driven means is disposed within a region of a process fluid, and includes radially and axially extending passages for centrifugally establishing process fluid circulat-ion over said second magnetic means.
22. A magnetic coupling as set forth in claim 18 or 20 including process fluid bearings for supporting said driven means, said bearings being disposed between said port and the wall so that fluid is circulated through said bearings.
23. A magnetic coupling as set forth in claim 19 including a pair of opposed peripheral flanges on said driven shaft for concentric reception over the opposite ends of said second sleeve for radially containing said second sleeve.
24. A magnetic coupling for coupling rotational motion through a sealed wall comprising a rotatable driving shaft on one side of the wall; first and second magetically coupled samarium-cobalt magnetic means; an axial first sleeve having one end received over one end of said driving shaft and radially containing said first samarium-cobalt magnetic means under centri-fugal compression during rotation; connecting means for connect-ing said first sleeve to said driving shaft to allow relative radial movement therebetween; a rotatable driven shaft disposed in a region of process fluid on the other side of said wall; and a second axial sleeve secured to said driven shaft and radially containing said second samarium-cobalt magnetic means under centrifugal compression during rotation, said second sleeve and second magnetic means being concentrically received within said first sleeve and first magnetic means, said driven shaft including radially and axially extending passages for centri-fugally establishing process fluid circulation over said first magnetic means.
25. A magnetic coupling as set forth in claim 24 including process fluid bearings for supporting said driven means, said bearings being disposed so that fluid is circulated through said bearings.
26. A method of manufacturing a magnetic coupling for magnetically coupling rotational motion through a sealed wall comprising the steps of providing rotatable driving means on one side of the wall; mounting first magnetic means on said driving means for maintaining said first magnetic means under centrifugal compression upon rotation; providing rotatable driven means on the opposite side of the wall axially aligned with the driving means; mounting second magnetic means magnetically coupled to the first magnetic means on said driven means for maintaining said second magnetic means under centrifugal compression upon rotation and in magnetic coupling relation with said first magnetic means.
27. The method of claim 26 including the step of position-ing one of said first and second magnetic means concentrically within the other of said magnetic means.
28. The method of claim 26 wherein said step of mounting said first magnetic means comprises radially containing said first magnetic means within an axial sleeve, and mounting said sleeve on said driving means for allowing radial enlargement thereof during rotation.
29. The method of claims 26 or 28 wherein said step of mounting said second magnetic means comprises radially containing said second magnetic means within axial second sleeve, and mount-ing said second sleeve on said driven means with its opposed ends radially contained by flange means on said driven means.
30. The method of claim 26 including the step of providing samarium-cobalt magnets for at least one of said first and second magnetic means.
31. A method of manufacturing a magnetic coupling for magnetically coupling rotational motion through a sealed wall comprising the steps of providing rotatable driving means on one side of the wall; mounting first samarium-cobalt magnetic means on said driving means for maintaining said first samarium-cobalt magnetic means under centrifugal compression upon rotation;
providing rotatable driven means on the opposite side of the wall axially aligned with the driving means; mounting second samarium-cobalt magnetic means magnetically coupled to the first samarium-cobalt magnet means on said driven means concentrically within said first samarium-cobalt magnetic means for maintaining said second samarium-cobalt magnetic means under centrifugal compression upon rotation and in magnetic coupling relation with said first samarium-cobalt magnetic means.
32. The method of claim 31 wherein said step of mounting said first magnetic means comprises radially containing a plural-ity of axially extending magnets within a first axial sleeve, and mounting said first sleeve on said driving means to allow relative radial movement therebetween; said step of mounting said second magnetic means comprising radially containing a like plurality of axially extending magnets with a second axial sleeve, and mounting said second sleeve on said driven means.
33. A method of manufacturing a magnetic coupling for magnetically coupling rotational motion through a sealed wall comprising the steps of providing a rotatable driving shaft on one side of the wall; radially containing first samarium-cobalt magnetic means within a first axial sleeve for maintaining said first magnetic means under centrifugal compression upon rotation; mounting said first sleeve on said first shaft to allow radial expansion of said first sleeve; providing a rotatable driven shaft on the opposite side of the wall axially aligned with said driving shaft; radially containing second samarium-cobalt magnetic means magnetically coupled to the first samarium-cobalt magnetic means within a second axial sleeve for maintain-ing said second magnetic means under centrifugal compression upon rotation; and mounting said second sleeve on said driven shaft disposed concentrically within said first sleeve.
34. The method of claims 27 or 31 or 33 including the steps positioning said driven means in a region of a process fluid, and forming radially and axially extending passages in said driven means for centrifugally establishing process fluid circulation over said second magnetic means.
35. The method of claims 27 or 31 or 33 including the steps of positioning said driven means in a region of a process fluid, forming radially and axially extending passages in said driven means for centrifugally establishing process fluid circu-lation over said second magnetic means, and supporting said driven means with process fluid bearings disposed with respect to the passages formed in said driven means so that fluid is circulated through the bearings.
36. A method of manufacturing a magnetic coupling for magnetically coupling rotational motion through a sealed wall comprising the steps of providing a rotatable driving shaft on one side of the wall; radially containing first samarium-cobalt magnetic means within a first axial sleeve for maintain-ing said first magnetic means under centrifugal compression upon rotation; mounting said first sleeve on said first shaft to allow radial expansion of said first sleeve; providing a rotat-able driven shaft on the opposite side of the wall axially aligned with said driving shaft; radially containing second samarium-cobalt magnetic means magnetically coupled to the first samarium-cobalt magnetic means within a second axial sleeve for maintaining said second magnetic means under centrifugal com-pression upon rotation; mounting said second sleeve on said driven shaft disposed concentrically with said first sleeve;
positioning said driven means in a region of a process fluid;
and forming radially and axially extending passages in said driven means for centrifugally establishing process fluid circulation over said second magnetic means.
37. The method of claim 36 including the step of support-ing said driven means with process fluid bearings disposed with respect to the passages formed in said driven means so that fluid is circulated through the bearings.
CA000320332A 1978-04-24 1979-01-26 High speed magnetic coupling with ceramic magnets maintained under centrifugal compression Expired CA1153414A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US899,669 1978-04-24
US05/899,669 US4277707A (en) 1978-04-24 1978-04-24 High speed magnetic coupling

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CA1153414A true CA1153414A (en) 1983-09-06

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CA000320332A Expired CA1153414A (en) 1978-04-24 1979-01-26 High speed magnetic coupling with ceramic magnets maintained under centrifugal compression

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US (1) US4277707A (en)
JP (1) JPS54145842A (en)
CA (1) CA1153414A (en)
DE (1) DE2916033A1 (en)
FR (1) FR2424443A1 (en)
GB (1) GB2021327B (en)
IT (1) IT1116487B (en)
SE (1) SE7902097L (en)

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Also Published As

Publication number Publication date
US4277707A (en) 1981-07-07
SE7902097L (en) 1979-10-25
JPS6142510B2 (en) 1986-09-22
FR2424443A1 (en) 1979-11-23
GB2021327B (en) 1983-01-19
JPS54145842A (en) 1979-11-14
IT1116487B (en) 1986-02-10
DE2916033C2 (en) 1987-03-19
IT7948460A0 (en) 1979-03-23
DE2916033A1 (en) 1979-10-25
FR2424443B1 (en) 1984-10-26
GB2021327A (en) 1979-11-28

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