Classifications

• • 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
  • F16C32/00—Bearings not otherwise provided for
  • F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
  • F16C32/0406—Magnetic bearings
  • F16C32/044—Active magnetic bearings
  • F16C32/0474—Active magnetic bearings for rotary movement
  • F16C32/0476—Active magnetic bearings for rotary movement with active support of one degree of freedom, e.g. axial magnetic bearings
  • F16C32/0478—Active magnetic bearings for rotary movement with active support of one degree of freedom, e.g. axial magnetic bearings with permanent magnets to support radial load
• • 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
  • F16C32/00—Bearings not otherwise provided for
  • F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
  • F16C32/0406—Magnetic bearings
  • F16C32/0408—Passive magnetic bearings
  • F16C32/041—Passive magnetic bearings with permanent magnets on one part attracting the other part
• • 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
  • F16C32/00—Bearings not otherwise provided for
  • F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
  • F16C32/0406—Magnetic bearings
  • F16C32/0408—Passive magnetic bearings
  • F16C32/041—Passive magnetic bearings with permanent magnets on one part attracting the other part
  • F16C32/0412—Passive magnetic bearings with permanent magnets on one part attracting the other part for radial load mainly
  • F16C32/0414—Passive magnetic bearings with permanent magnets on one part attracting the other part for radial load mainly with facing axial projections
• • 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
  • F16C32/00—Bearings not otherwise provided for
  • F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
  • F16C32/0406—Magnetic bearings
  • F16C32/044—Active magnetic bearings
  • F16C32/0459—Details of the magnetic circuit
  • F16C32/0461—Details of the magnetic circuit of stationary parts of the magnetic circuit
  • F16C32/0465—Details of the magnetic circuit of stationary parts of the magnetic circuit with permanent magnets provided in the magnetic circuit of the electromagnets
• • 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
  • F16C2300/00—Application independent of particular apparatuses
  • F16C2300/02—General use or purpose, i.e. no use, purpose, special adaptation or modification indicated or a wide variety of uses mentioned

Definitions

• the invention relates to a device for the magnetic bearing of a rotor shaft against a stator having the following features: a) A first bearing part is connected to the rotor shaft and from a second, the stator associated bearing part below
• the first bearing part contains perpendicular to the axis of the rotor shaft ⁇ aligned, arranged in the direction of the axis successively rotor disk elements which are each spaced to form a gap
• the second bearing part contains perpendicular to the axis of the Ro ⁇ torwelle aligned, arranged in the direction of the rotor axis behind ⁇ each other, spaced apart stator disk elements, each projecting into one of the interstices of adjacent rotor disk elements, d) between the elements, a substantially directed in the axial direction magnetic flux is formed.
• a corresponding storage facility is e.g. from DE 38 44 563 C2.
• Magnetic storage facilities allow a contact and wear-free storage of moving parts. They require no lubricant and can be designed with low friction.
• Conventional (conventional) radial or Axialmagnet ⁇ storage facilities use magnetic forces between stationary electromagnets of a stator and co-rotating ferromagnetic elements of a rotor body. The magnetic ⁇ forces are always attractive in this type of storage. As a consequence, in principle, not inherently stable bearing in al ⁇ len three spatial directions can be achieved.
• Such magnetic bearing devices therefore require active bearing control, which uses position sensors and control circuits to control the currents of electrical control magnets and counteract deviations of the rotor body from its desired position.
• the Rege multichannel executed ⁇ development requires a complex power electronics.
• Entspre ⁇ sponding magnetic bearing devices are for example larpumpen at Turbomoleku-, ultra centrifuges, high-speed spindles of machine tools and X-ray tubes with rotating anodes used; also a use in motors, generators, turbines and compressors is known.
• FIG. 1 The basic structure of a corresponding bearing device 30 is outlined in FIG.
• five associated control loops rl to r4 or z5 are required here.
• the state of the art also includes stable storage facilities with magnetic flux, soft magnetic parts such as iron and with permanent magnets in one direction.
• permanent magnet rings are aligned on a shaft axially primarily with the poles ei ⁇ nes iron yoke and cause such a radial centering.
• the magnetic flux is amplified here by excitation coils, where ⁇ if necessary, the axially unstable degree of freedom is stabilized by an electronic control loop.
• a plurality of alternately stationary and rotating ring magnets axially one behind the other can be lined up with the same axial magnetization and fulfill a radial bearing function. Again, the axial degree of freedom must be actively stabilized.
• the object of the present invention is to provide a magnetic bearing device for a non-contact bearing of a shaft, in particular for a high-speed machine such as e.g. a turbocompressor to specify, which is less expensive compared to the cited prior art.
• a high-speed machine such as e.g. a turbocompressor to specify
• a high load-bearing capacity and a high bearing rigidity should be ensured.
• a first bearing part is connected to the rotor shaft and surrounded by a second, the stator associated bearing part with mutual spacing,
• the first bearing part contains perpendicular to the axis of the rotor shaft aligned ⁇ elements in the direction of the rotor shaft axis towards ⁇ arranged behind the other soft-magnetic rotor Scheib Enele which are spaced to form an intermediate space,
• the second bearing part contains se perpendicular to Rotorwellenach- aligned, arranged in succession in the direction of this axis, spaced-apart soft-magnetic stator disk elements, which protrude in each case in one of the intermediate spaces of adjacent rotor disk elements ⁇ ,
• the rotor disk elements and the stator disk elements are formed on their respectively mutually facing sides into annular tooth-like extensions, which each face one another via an air gap,
• stator disk elements are assigned magnetic-field-generating means for generating a magnetic holding flux directed essentially between the rotor disk elements and the stator disk elements in the axial direction,
• the bearing parts are each symmetrical with respect to a directed perpendicular to the rotor axis center plane divided into two bearing halves, and
• At least one stationary winding of an electric ⁇ magnet is provided in the middle plane with which a magnetic control flow is to be superimposed to the magnetic holding flux, so that the flux densities of the Steuerflus ⁇ ses and the holding flux on the one side of the rotor ⁇ disk elements additively superimposed on the respectivemélie ⁇ ing side subtractive.
• the external magnetic field generating means a magnetic holding flux over the respective bearing gap and magnetize the tooth-like extensions of the weichmagneti ⁇ rule, especially iron-containing material.
• the magnetic flux density in the respective gap is inhomogeneous, whereby forces are exerted on the iron surface.
• a considerably larger magnetization and thus a larger bearing force per area can be achieved in iron-containing material than in arrangements with permanent magnet material such as neodymium-iron-boron (Nd-Fe-B) alone.
• the system will minimize the magnetic resistance and the tooth-like projections so align ⁇ that they face each other as close as possible. In the equilibrium position then the tooth-like projections are exactly opposite; at radial deflection cause the magnetic holding forces a proportional restoring force; ie a radial control is then no longer necessary.
• the maximum radial force is applied when displaced by half the width of the tooth-like extensions. Since the lengths ⁇ scale by the radial width of projections plus Between the seats ⁇ rule lying gaps is given, the bearing stiffness can be selected by the dimensions of the tooth-like projections in a wide range. In particular, can be realized by a fine structuring of the tooth-like extensions very rigid storage devices. In a symmetrical arrangement with the same bearing gaps on both sides, the axial forces cancel the rotor disk elements. However, the equilibrium is axially unstable ⁇ ses and must be stabilized by additional means such as actively controlled axial bearing parts. However, only one single control loop for a single thrust bearing is required per shaft instead of five as in the prior art with actively controlled radial bearings.
• An inventively designed magnetic bearing device is thus characterized by a stable, unregulated radial leadership and a single, to be carried out in a simple manner axial control.
• the apparatus may advantageously following shopping ⁇ male comprise:
• axially extending soft magnetic material for closing the magnetic flux circuits may be provided outside the intermediate spaces between the disk elements on their radially inner side and outer side.
• the soft magnetic material may be provided by an axially extending outer yoke body and / or by at least parts of the rotor shaft. With such parts of soft magnetic material, the magnetic resistance of the magnetic flux circuit can be reduced, so that so that a corresponding increase in the flux density between the tooth-like projections and thus improved magnetic rigidity can be achieved.
• the magnetic field generating means for generating the holding flux can be permanent magnetic elements, wherein these permanent magnetic elements can be integrated at least into some of the stator disk elements.
• Corresponding storage devices are relatively compact to build.
• these permanent magnetic elements can advantageously be arranged in each case between two axial halves of a stator disk element. It is • advantageous in view of high flux densities Zvi ⁇ rule the disc elements and an effective use of the permanent magnetic material when the stator disk elements are provided with the perma ⁇ nentmagnetica elements radially have a greater extension than the neighboring rotor disk elements without permanent-magnet elements.
• these magnetic-field-generating means are formed by at least one winding of an electromagnet.
• this at least one magnet ⁇ winding for generating the holding flux in each storage half enclose each at least some of the rotor disk elements with spacing.
• the at least one winding of the can Elektromag ⁇ Neten for generating the magnetic either a magnetic holding flux and the magnetic control flux leading average rotor disc element to query, or a rotor shaft surrounded contact-free manner at its leading magnetic field outside.
• the mutually facing flat sides of the rotor disk elements and the stator disk elements provided with the tooth-like extensions can be inclined relative to a perpendicular to the rotor shaft axis .
• wedge-shaped longitudinal sectional shapes of the elements result.
• the axial extent (or slice thickness) and the angle of inclination are chosen so that the disc elements can absorb the magnetic flux everywhere, without getting into the magneti ⁇ cal saturation.
• At least one axial distance sensor, nominal value transmitter and regulator with amplifier must be assigned to control an electric current provided by the at least one control magnet winding for generating the magnetic control flux.
• the illustrated in Figure 2 magnetic storage device has a symmetrical to a median plane Me structure with two bearing halves LhI and Lh2.
• the device comprises a contactless to be stored Rotorwel ⁇ le 3 with a co-rotating first bearing part 4, which in each bearing half aligned perpendicular to the axis A of the rotor shaft, attached to this, co-rotating Rotorusionn ⁇ elements 4i made of soft magnetic material such as iron on ⁇ has.
• the rotor disk elements 4i are arranged in the axial direction one behind the other, forming respective intermediate spaces 5j.
• a central rotor disk element is 4z just ⁇ if appropriate of the soft magnetic material on the rotor shaft 3, said member having towards the rotor disk elements 4i in the two bearing halves of a relatively larger axial From ⁇ strain.
• a stationary stator of the magnetic bearing device 2 forms a second bearing part 7 with likewise axially spaced, annular disk-shaped stator disk elements 7i enclosing the rotor shaft 3 at a spacing.
• This stator disk from also soft Mate ⁇ rial project without contact into the spaces 5j radially toward ⁇ , so that in each bearing half LHI, Lh2 an axially alternating, comb-like arrangement of rotor disk elements 4i and Statorelectricnettin 7i results.
• the rotor disk elements and the stator disk elements are ih ⁇ ren respectively mutually facing flat sides with concentrically surrounding annular tooth-like projections 4f and 7f provided and designed to such projections.
• these tooth-like extensions are obtained by incorporating annular, concentric grooves or grooves in the two opposite flat sides of corresponding iron discs.
• the tooth-like processes of both Disc elements face each other over a small air gap 8k.
• the stator disk elements 7i are assigned means for generating a magnetic flux which is axial via the air gaps 8k between the rotor disk elements and the stator disk elements.
• Whose field lines are indicated in the figure with Deutschengezoge ⁇ NEN lines and designated with MFI.
• the system tries accordance with the reluctance of the magnetic resistance to minimize and for For the tooth-like projections so ⁇ judge that they are in a position of equilibrium genübermaschine exactly ge ⁇ . In a radial deflection, however, the magnetic forces cause a proportional restoring force; ie, a radial control is not necessary.
• the magnetic flux serving for this radial guidance or mounting of the rotor shaft 3 with its attached thereto, in particular magnetic-flux-carrying parts, can therefore also be referred to as a "radial holding flux".
• each Statorusionnelement 7i is divided axially into two halves, between which a radially extending layer or annular disk 7m is of a permanent magnetic material such as in particular ⁇ NdFeB for generating.
• the stator disk elements 7i advantageously have a greater radial extent than their grooved effective area with the tooth- like extensions 7f. In this way, flux densities of, in particular, 1 Tesla or more can be achieved in the air gaps 8k and the magnetic material can be operated at a working point, for example between 0.5 and 0.8 Tesla when using NdFeB with a large energy product BH.
• Rotor section ⁇ elements 4e formed as flux guides, which together with a ferromagnetic flux feedback on the existing at least on its outer side of ferromagnetic material rotor shaft close the magnetic circuit.
• a centering radial and decentering axial force action in the magnetic bearing device 2 is caused by the inhomogeneities of the magnetic field in the air gaps 8k caused by the tooth-like projections 4f and 7f of the disk elements 4i and 7i.
• the tooth-like projections acts in the storage device additionally perpendicular to the surfaces of weichmagneti ⁇ 's parts an attractive force density whose size ⁇ B> 2 / 2 ⁇ 0 .
• the size ⁇ B> represents the mean value of the Flußdich ⁇ te, which is usually the same in the air gaps on both sides of a rotor disk element, so that cancel the corresponding axial forces.
• the outer yoke body 11 for the control flux Mf2 is spaced from the stator disc elements 7i by a distance a, the magnitude a being generally between 2 and 10 times the width w of the air gaps 8k.
• the intermediate ⁇ body 10 of non-magnetic material.
• FIG 3 a corresponding embodiment of a magnetic bearing device according to the invention in Figure 2 corresponding representation is shown and generally designated 12.
• the co-rotating rotor disk elements 4i are fixedly arranged coils 131 of an electromagnet in the area of rapid Dialen outside where ⁇ 7i extend radially in the stator disk elements between the individual magnetic coils 131 therethrough.
• the magnetic flux circuit for the holding flux MfI is closed by way of an outer yoke body 14, on which the stator disk elements 7i respectively rest directly with their radial outer side.
• the rotor shaft 3 is here also made of magnetic material.
• the individual rotor disk elements 4i are magnetically decoupled from the rotor shaft 3 via a sleeve-like intermediate body 15 with radial expansion a of non-magnetic material.
• the size a is selected as in the embodiment according to FIG.
• the magnetic control flux Mf2 is also caused by a stationary winding 17 of an electromagnet.
• This control solenoid winding 17 is located here JE but in a rotor shaft region close to the center plane Me, not countries around the river curve of the holding flux Mfl to behin ⁇ . Therefore, a central rotor disk element is also omitted in this area.
• the control flux Mf2 closes close to the axis via the rotor shaft 3 and axially away via the stator end disk elements 7e adjoining one another in the region of the center plane Me and the outer yoke body 14.
• the magnetic field generating means for generating the magnetic holding flux MfI are either permanent magnetic elements 7m or windings 131 of at least one exciting magnet.
• the desired axial holding Flow MfI on the tooth-like extensions 4f and 7f also ei ⁇ ne combination of permanent magnetic elements and windings of electromagnets possible.
• the magnetic bearing devices 2 and 12 can also be operated according to the invention aligned so that their rotor shaft axis A is not horizontal, but is directed obliquely or perpendicular thereto.
• the advantage of the construction of magnetic bearing devices according to the invention can be seen in the omission of a separate thrust bearing in a shaft bearing.
• the magnetic axial field of the radial bearing function acts linearizing on the current-force characteristic of the axial position control. By minimizing the current value in the control concept, the
• a held with one or two such magnetic bearing devices rotor shaft 3 can be kept contactless with an axial position control.
• a corresponding, for example, below with two identically constructed magnetic bearing devices 2 and 2 'equipped to figure 2 magnetic bearing 24 con- tains according to the direction indicated in Figure 4 control block diagram of at least one distance sensor 25, a Sollwertge ⁇ about 26, a comparator device 27 and a controller device 28 with downstream amplifier.
• This amplifier controls the axial control winding of the one, preferably both magnetic bearing devices in series and holds an axial target position.
• the force-current characteristic is almost linear; ie, when power is reversed, the direction of force is reversed. This simplifies the design and stability of the control.
• the axial position can, for example, the center position of the rotor disk elements 4i between the neighboring th stator disk elements 7i are specified.
• the control is tert a different target Erwei ⁇ what is to be the time mean value of the coil current is close to zero.
• this is the integral of the magnetic ⁇ current, multiplied by a scaling factor as a Posi ⁇ tion setpoint Z 0 in the comparison circuit device 27 for the actual position is compared by the distance sensor 25th The difference acts as a control deviation via the regulator device 28 with the amplifier back to the current.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Magnetic Bearings And Hydrostatic Bearings (AREA)

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Citations (2)

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• 2005
  • 2005-06-28 DE DE102005030139A patent/DE102005030139B4/de not_active Expired - Fee Related
• 2006
  • 2006-06-22 US US11/988,037 patent/US8058758B2/en not_active Expired - Fee Related
  • 2006-06-22 EP EP06763831A patent/EP1896741A2/de not_active Withdrawn
  • 2006-06-22 CN CN200680023485XA patent/CN101218445B/zh not_active Expired - Fee Related
  • 2006-06-22 WO PCT/EP2006/063438 patent/WO2007000405A2/de active Application Filing

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Non-Patent Citations (1)

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