CN104214218A - Method and structure capable of balancing static loads in magnetic bearing - Google Patents

Method and structure capable of balancing static loads in magnetic bearing Download PDF

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Publication number
CN104214218A
CN104214218A CN201410387668.6A CN201410387668A CN104214218A CN 104214218 A CN104214218 A CN 104214218A CN 201410387668 A CN201410387668 A CN 201410387668A CN 104214218 A CN104214218 A CN 104214218A
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CN
China
Prior art keywords
static load
balance
differewntial
electromagnet
electromagnets
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CN201410387668.6A
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Chinese (zh)
Inventor
徐龙祥
金超武
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Nanjing University of Aeronautics and Astronautics
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Nanjing University of Aeronautics and Astronautics
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Priority to CN201410387668.6A priority Critical patent/CN104214218A/en
Publication of CN104214218A publication Critical patent/CN104214218A/en
Pending legal-status Critical Current

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Abstract

The invention discloses a method and structure capable of balancing static loads in a magnetic bearing. According to the method capable of balancing the static loads in the magnetic bearing, two differential electromagnets with unequal magnetic pole areas are adopted by a freedom degree with the static loads required to be balanced, and therefore a control current generated by the static loads tends to be zero. It can be seen that a method that the magnetic pole areas of the two differential electromagnets in the magnetic bearing are designed to be different is adopted to balance the static loads, the structural design of a fluid flow machine is simplified, and the efficiency and reliability of the fluid flow machine are improved.

Description

Method and the structure thereof of static load in magnetic suspension bearing can be balanced
Technical field
What the present invention relates to is a kind of method and structure thereof that can balance static load in magnetic suspension bearing, belongs to magnetic suspension bearing field.
Background technique
Active Magnetic Suspending Bearing utilizes electromagnetic force by being suspended in space by suspended matter, makes by a kind of high-performance bearing realizing mechanical between suspended matter with stator and contact.Compare with sliding bearing with traditional rolling bearing, Active Magnetic Suspending Bearing has two large advantages: 1. do not have Mechanical Contact, without the need to lubrication system, there is not lubrication leakage pollution problem; 2. supporting force is controlled.Therefore Active Magnetic Suspending Bearing not only can be applied to high rotating speed, vacuum, the ultra-clean and particular job such as extreme temperature and pressure environment; And the feature that its supporting force can be utilized controlled carries out vibration balancing to by the vibration of suspended matter, the vibration of reduction system, the performance of raising system, has broad application prospects in high-speed rotating machine (blower, compressor, motor, pump and steam turbine etc.).
When adopting Active Magnetic Suspending Bearing supporting, often there is certain static load (as gravity, hydrodynamic pressure etc.), usual Active Magnetic Suspending Bearing single-degree-of-freedom in office all adopts the pair of differential electromagnet structure (as shown in Figure 1) of area equation, due to the existence of static load, the electric current in two differewntial electromagnet field coils will be made unequal, namely a coil current is large, and a coil current is little.As static load is large, one of them coil current will be made excessive and affect its working life, serious meeting makes coil burn out, and causes serious accident.Therefore, effective ways must be taked to be balanced static load, ensure the reliable operation of machinery.For the hydrodynamic pressure (static load) vertically produced by fluid machine blade wheel, the following two kinds of balance methods of general employing at present: (1) is being arranged Balance disc by suspended matter, select suitable mounting point, make the draught head that the both sides of Balance disc keep certain, thus the load that generation one is contrary with the hydrodynamic pressure vertically that impeller produces, thus balancing a part of static load, the deficiency of this method needs increase Balance disc and can lower efficiency; (2) apply an electromagnetic force or permanent magnetic in the opposite direction of the hydrodynamic pressure vertically of fluid machine blade wheel generation, thus balance a part of static load, the deficiency of this method needs to increase magnet, causes complex structure.New structure of the present invention adopts the unequal poor electromagnet of magnetic pole area, and the electromagnetic force that the electromagnet that magnetic pole area is large provides has the effect of two aspects, and one is realize magnetic suspension, and two is balance static loads.Structurally substantially identical with traditional magnetic suspension bearing, be all adopt the electromagnet of pair of differential, difference is only that the magnetic pole area of differential electromagnet is unequal, and structure is very simple.
Summary of the invention
The present invention is directed to the deficiencies in the prior art, a kind of method that can balance static load in magnetic suspension bearing is provided, it adopts unequal two differewntial electromagnets of magnetic pole area, namely can balance the static load that the degrees of freedom residing for aforementioned two differewntial electromagnets has; The present invention can active balance static load, technique simple and reliable.
For realizing above technical purpose, the present invention will take following technological scheme:
A method for static load in magnetic suspension bearing can be balanced, for needing the degrees of freedom balancing static load, adopting unequal two differewntial electromagnets of magnetic pole area, going to zero to make the control electric current produced by static load.
Another technical purpose of the present invention is to provide a kind of magnetic suspension bearing new structure that can balance static load, on single-degree-of-freedom in office, all there are two differewntial electromagnets, in two differewntial electromagnets corresponding in described each degrees of freedom, be in and need the magnetic pole area of two differewntial electromagnets balanced in the degrees of freedom of static load unequal.
As a further improvement on the present invention, be in and need to balance in two differewntial electromagnets in the degrees of freedom of static load, the magnetic pole area of the differewntial electromagnet that the magnetic pole area of the differewntial electromagnet that electromagnetic force direction is identical with static load direction is contrary with static load direction relative to electromagnetic force direction is less.
As a further improvement on the present invention, the ratio of the magnetic pole area of two differewntial electromagnets in the degrees of freedom needing balance static load, determines according to the static load size of required balance.
As a further improvement on the present invention, described magnetic suspension bearing new structure is axial magnetic bearing structure.
As a further improvement on the present invention, described magnetic suspension bearing new structure is axial magnetic suspension bearing structure.
According to above technological scheme, relative to prior art, the present invention has following advantage:
The present invention, by two the electromagnet pole sizes adopted in the magnetic suspension bearing of differential form are designed to the balance that diverse ways carries out static load, simplify the structural design of fluid machinery, improves efficiency and the reliability of fluid machinery.
Accompanying drawing explanation
Fig. 1 is the magnetic pole area equation of traditional magnetic suspension principle figure, pair of differential electromagnet.
Fig. 2 is magnetic suspension principle figure of the present invention, and the magnetic pole area of pair of differential electromagnet is unequal.
Fig. 3 is 8 poles of the present invention (two pairs of differewntial electromagnets) axial magnetic bearing structure, and the magnetic pole area of every a pair differewntial electromagnet is unequal, can balance gravity vertically downward or other power F.
Fig. 4 is a kind of axial magnetic suspension bearing structure of the present invention, and the magnetic pole area of pair of differential electromagnet is unequal, can balance axial force F left.
Fig. 5 is another kind of axial magnetic suspension bearing of the present invention, and the magnetic pole of one of them electromagnet has moved on to radial direction from the axis Fig. 4, is equivalent to the magnetic pole area reducing this electromagnet.
Embodiment
Technological scheme of the present invention is explained below with reference to accompanying drawing.
The method that can balance static load in magnetic suspension bearing of the present invention, for needing the degrees of freedom balancing static load, adopting unequal two differewntial electromagnets of magnetic pole area, going to zero to make the control electric current produced by static load; It can thus be appreciated that, the magnetic pole size of the electromagnet of two in one degree of freedom is designed to difference by the present invention, make two electromagnet when gap density is equal with coil current, the electromagnetic force difference produced by size difference is balanced by the static load on suspended matter.
The present invention is according to above-mentioned technical concept, provide a kind of magnetic suspension bearing new structure that can balance static load, on single-degree-of-freedom in office, all there are two differewntial electromagnets, in two differewntial electromagnets corresponding in described each degrees of freedom, be in and need the magnetic pole area of two differewntial electromagnets balanced in the degrees of freedom of static load unequal; Be in and need to balance in two differewntial electromagnets in the degrees of freedom of static load, the magnetic pole area of the differewntial electromagnet that the magnetic pole area of the differewntial electromagnet that electromagnetic force direction is identical with static load direction is contrary with static load direction relative to electromagnetic force direction is less; The ratio of the magnetic pole area of two differewntial electromagnets in the degrees of freedom needing balance static load, determines according to the static load size of required balance.
Feasibility of the present invention is explained below with reference to several embodiment.
Fig. 1 is maglev basic principle figure, and adopt the electromagnet of pair of differential form in the vertical direction, wherein 1,2 is electromagnet, and 3 is by suspended matter.Normal conditions, the magnetic pole area equation of pair of differential electromagnet and power-on and power-off magnet, the magnetic induction intensity produced in air gap is:
Wherein nfor coil turn; ifor passing into the electric current in coil; xfor by the air gap between suspended matter and electromagnet; μ 0for permeability of vacuum; afor the magnetic pole area of electromagnet.The electromagnetic force produced is:
When being subject to a static load F effect by suspended matter, in order to make still to be suspended in equilibrium position by suspended matter, the electromagnetic force that power-on and power-off magnet produces will be no longer equal, and the electric current namely in power-on and power-off magnet coil is no longer equal, now power-on and power-off magnet electromagnetic power make a concerted effort be:
Wherein i 0for without static load, to be in equilibrium position (centre of pair of differential electromagnet) by suspended matter time bias current; i mfor the control electric current produced due to static load; x 0during for being in equilibrium position by suspended matter, electromagnet and by the air gap between suspended matter.
When static load is ftime, should have:
(1)
After Active Magnetic Suspending Bearing has designed, a, n, i 0with x 0for fixed value, along with the increase of static load, control electric current i malso can along with increase, the actual current in upper electromagnet be ( i 0+ i m), the actual current in lower electromagnet be ( i 0- i m), cause the difference between current in power-on and power-off magnet coil to strengthen.Thus making a work of electromagnet at big current, another work of electromagnet at small area analysis, thus makes the field coil temperature drift of an electromagnet, and the Active Magnetic Suspending Bearing reliability of this differential form is on the low side.
When employing power-on and power-off magnet poles area a 1, a 2(magnetic pole area time different a 1, a 2optimal proportion be make control electric current i m=0), assuming that i m=0, according to Fig. 2, when being still suspended in equilibrium position by suspended matter, upper and lower two electromagnet electromagnetic forces make a concerted effort be:
When static load is ftime, should have:
(2)
Formula (2) shows, static load can be balanced by a pair unequal differewntial electromagnet of magnetic pole area, and can not cause the unequal situation of differewntial electromagnet field coil electric current.
For radial magnetic bearing, can be designed to as shown in Figure 32 to pole difference structure, i.e. 8 pole electromagnet structures (also can be 12 poles, 16 poles, 18 poles or 24 poles), the area of two electromagnet of every a pair pole is unequal, downward gravity or other power F can be balanced, wherein 1,2,5,6 is electromagnet, and 3 is by suspended matter, and 4 is field coil.
For axial magnetic suspension bearing, can be designed to electromagnet structure as shown in Figure 4, the magnetic pole area of left side electromagnet is little, and the magnetic pole area of the right electromagnet is large, and can balance axial force F left, wherein 1,2 is electromagnet, and 3 is by suspended matter; 4 is field coil.Electromagnet structure as shown in Figure 5 can be adopted, the outer shroud magnetic pole of left side electromagnet has moved on to the radial direction in Fig. 5 from the axis Fig. 4, be equivalent to the magnetic pole area reducing half, also can balance axial force F left, wherein 1,2 is electromagnet, and 3 is by suspended matter; 4 is field coil.

Claims (6)

1. one kind can balance the method for static load in magnetic suspension bearing, it is characterized in that: for the degrees of freedom needing to balance static load, adopt unequal two differewntial electromagnets of magnetic pole area, go to zero to make the control electric current produced by static load.
2. one kind can balance the magnetic suspension bearing new structure of static load, on single-degree-of-freedom in office, all there are two differewntial electromagnets, it is characterized in that, in two differewntial electromagnets corresponding in described each degrees of freedom, be in and need the magnetic pole area of two differewntial electromagnets balanced in the degrees of freedom of static load unequal.
3. can balance the magnetic suspension bearing new structure of static load according to claim 2, it is characterized in that, be in and need to balance in two differewntial electromagnets in the degrees of freedom of static load, the magnetic pole area of the differewntial electromagnet that the magnetic pole area of the differewntial electromagnet that electromagnetic force direction is identical with static load direction is contrary with static load direction relative to electromagnetic force direction is less.
4. can balance the magnetic suspension bearing new structure of static load according to claim 3, it is characterized in that, the ratio of the magnetic pole area of two differewntial electromagnets in the degrees of freedom needing balance static load, determines according to the static load size of required balance.
5. can balance the magnetic suspension bearing new structure of static load according to claim 4, it is characterized in that, described magnetic suspension bearing new structure is axial magnetic bearing structure.
6. can balance the magnetic suspension bearing new structure of static load according to claim 4, it is characterized in that, described magnetic suspension bearing new structure is axial magnetic suspension bearing structure.
CN201410387668.6A 2014-08-07 2014-08-07 Method and structure capable of balancing static loads in magnetic bearing Pending CN104214218A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113885298A (en) * 2021-09-22 2022-01-04 哈尔滨工业大学 Magnetic suspension type mask table of photoetching machine
CN115111265A (en) * 2022-07-21 2022-09-27 重庆开山流体机械有限公司 Asymmetric electromagnetic bearing

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001224154A (en) * 2000-02-10 2001-08-17 Japan Science & Technology Corp Method and apparatus for multipole magnetically levitating rotation
CN101242151A (en) * 2007-02-06 2008-08-13 宝山钢铁股份有限公司 Suspending magnetic stagnant compensation method
CN102072249A (en) * 2011-01-13 2011-05-25 北京航空航天大学 Large-bearing-capacity radial magnetic bearing
CN102628476A (en) * 2012-03-30 2012-08-08 刘延风 Axial electromagnet bearing

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001224154A (en) * 2000-02-10 2001-08-17 Japan Science & Technology Corp Method and apparatus for multipole magnetically levitating rotation
CN101242151A (en) * 2007-02-06 2008-08-13 宝山钢铁股份有限公司 Suspending magnetic stagnant compensation method
CN102072249A (en) * 2011-01-13 2011-05-25 北京航空航天大学 Large-bearing-capacity radial magnetic bearing
CN102628476A (en) * 2012-03-30 2012-08-08 刘延风 Axial electromagnet bearing

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113885298A (en) * 2021-09-22 2022-01-04 哈尔滨工业大学 Magnetic suspension type mask table of photoetching machine
CN115111265A (en) * 2022-07-21 2022-09-27 重庆开山流体机械有限公司 Asymmetric electromagnetic bearing

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Application publication date: 20141217