CN103343821B - Be applicable to high-revolving magnetic fluid movable sealing structure - Google Patents
Be applicable to high-revolving magnetic fluid movable sealing structure Download PDFInfo
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- CN103343821B CN103343821B CN201310252516.0A CN201310252516A CN103343821B CN 103343821 B CN103343821 B CN 103343821B CN 201310252516 A CN201310252516 A CN 201310252516A CN 103343821 B CN103343821 B CN 103343821B
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Abstract
One is applicable to high-revolving magnetic fluid movable sealing structure.Thus it mainly solves the centrifugal force that existing magnetic fluid movable sealing structure cannot overcome magnetic fluid itself can not bear the technical problems such as high rotating speed.It comprises cylindric static magnetic pole (7) and is coaxially sleeved on static magnetic pole (7) cylindric rotary pole (4) outward, described static magnetic pole (7) one end is fixed on casing (8), the cylinder outer surface of described static magnetic pole (7) is provided with more than two seal rings (6) given prominence to, running shaft (1) passes from the axle center hole of described static magnetic pole (7) and connects firmly integral with described rotary pole (4), radial clearance between described seal ring (6) and the magnetic conduction internal surface of rotary pole (4) is provided with magnetic fluid (3) and coordinates with the magnetic fluid motive sealing realized between static magnetic pole (7) with rotary pole (4).It has good sealing effect, the advantage of excellent heat dissipation performance, can bear the linear velocity being greater than 20 meter per seconds.
Description
Technical field
The present invention relates to a kind of magnetic fluid movable sealing structure, particularly a kind of for high-revolving magnetic fluid movable sealing structure.
Background technique
Magnetic fluid ferromagnetic particle is dispersed in a kind of colloidal system formed in carrier fluid, and its existing strong magnetism has mobility again, can maintain a long-term stability under the effect of the many kinds of force such as gravity, magnetic force, do not produce precipitation and layering.The principle of magnet fluid sealing utilizes magnetic field to retrain magnetic fluid, make it be full of seal space and form " liquid O RunddichtringO ", and suitable carrier fluid can infiltrate sealing surface well, reaches extraordinary sealing effect.When the saturation vapour pressure of carrier fluid is enough low, even if be also difficult to volatilization under high vacuum environment, above-mentioned magnet fluid sealing can be applied to vacuum seal.Magnet fluid sealing has the following advantages: 1, good seal performance, easily repair; 2, long, low in energy consumption without wearing and tearing, life-span; 3, structure is simple, cost is low, reliability is high.Above-mentioned advantage makes it in motive sealing field, and particularly vacuum dynamic seal field obtains a wide range of applications.
But existing magnetic fluid movable sealing structure is that static magnetic pole is in outside, rotary pole is in inner side, when being applied under high speed conditions, larger centrifugal force make magnetic fluid from inner side (rotary side) laterally (Stationary side) move in a large number, cause the effective sealing thickness of magnetic fluid " O RunddichtringO " obviously to reduce, sealability is deteriorated even seal failure (as shown in Figure 4).
Meanwhile, because in magnetic fluid under high rotating speed, friction is violent, heating is serious, and when temperature is more than 80 degrees Celsius, the stability of sealability and magnetic fluid itself obviously declines.Although existing magnetic fluid movable sealing structure can carry out various pressure cooling in Stationary side, magnetic fluid itself is the poor conductor of heat, and the frictional heat of rotary side successfully can not be delivered to Stationary side.Rotary side is coated by magnetic fluid dynamic seal apparatus, cannot carry out heat transfer by convection, and less than 80 degrees Celsius thermal radiation are little in addition, so the frictional heat of rotary side can only be conducted by running shaft.And the heat radiation of high rotating speed Shaft and rotor difficulty all especially, cause the frictional heat of rotary side to pass smoothly, also have a strong impact on sealing effect.
In sum, in prior art, the inapplicable high speed conditions requirement of magnetic fluid movable sealing structure, generally only can be applicable to the operating mode of below sealing surface linear velocity 20 meter per second.
Prior art the rotating part of magnetic fluid movable sealing structure is placed on inner side, stationary part is placed on outside, centrifugal force from inside to outside, and outside is static, there is no centrifugal force, so centrifugal force cannot be utilized as the present invention to come centrifugal force resistant, its result is exactly that magnetic fluid is a large amount of toward external migration in seal clearance under centrifugal action, causes sealability to decline even seal failure.As shown in Figure 4.
Beneficial effect of the present invention is:
1, owing to present invention employs stationary part interior, rotating part movable sealing structure outside, under high-speed state, effectively utilizing centrifugal force makes magnetic fluid compress the sealing surface of rotary pole, and rotating speed is higher, fits tighter, avoid magnetic fluid a large amount of toward external migration from seal clearance, ensure that the magnetic fluid thickness in seal clearance, reach motive sealing effect good under high-speed working condition, its sealing surface can bear the higher line speed being greater than 20 meter per seconds.It has good sealing effect, the advantage of excellent heat dissipation performance.
2, the top of the sidewall of annular groove 41 is provided with chamfer surface or arc surface connects with rotary pole 4 internal surface, to possess enough spaces, rotary pole 4 can be avoided to follow in running shaft 1 rotary course when there is slight axial runout and circular runout and static magnetic pole 7 touches mill, the magnetic fluid outside outflow annular groove 41 can also be made to be back in annular groove 41 along arc surface or chamfer surface simultaneously.
3, because annular groove 41 is the grooves running through the setting of non-magnetic coating 42, there is the positive effect of following two aspects:
First, because annular groove 41 runs through non-magnetic coating 42, can ensure that bottom land is the internal surface (i.e. magnetic conduction internal surface) of rotating cylinder 2, even if non-magnetic coating 42 and rotating cylinder 2 are in conjunction with insecure, create gap between the two, cause leak, also can block by magnetic fluid 3, thus can not affect sealing effect.
The second, the setting of annular groove 41 and sidewall thereof does not affect Magnetic field distribution, does not spatially affect the distribution of magnetic fluid 3, as shown in Figure 3 yet.Static with under lower-speed state, the setting of annular groove 41 does not affect performance and the effect of magnetic fluid motive sealing.And at high speeds, due to the effect of annular groove 41, make the performance of magnetic fluid motive sealing and effect be unlikely to obvious weakening.
On the other hand, when the width of magnetic fluid 3, thickness, Magnetic flux density and seal ring 6 to arrange etc. technical parameter substantially identical with prior art time, then magnetic fluid movable sealing structure of the present invention and magnetic fluid movable sealing structure of the prior art similarity on sealing mechanism high, thus magnetic fluid motive sealing computation model of the prior art and relevant parameters can be maximally utilised, keep the advantage of magnetic fluid movable sealing structure in prior art to greatest extent.
4, one or two annular permanent magnets 5 are arranged at the one or both ends of static magnetic pole 7, namely inner end and/or outer end are arranged with the magnet ring 5 of radial magnetizing, and the magnet ring 5 being sheathed on inner end is oppositely arranged in polarity with the magnet ring 5 being sheathed on outer end, compared with magnetize mode and other possible modes that magnetizes of the prior art, tool has the following advantages respectively:
1) with annular permanent magnet 5 is installed on the intermediate portion of static magnetic pole 7 and compared with axial charging mode.When permanent magnet 5 is arranged at the intermediate portion of static magnetic pole 7, the mode of axial charging can only be used, static magnetic pole 7 is divided into two by permanent magnet 5, become two annulus, also with non-magnetic inner core, two static magnetic poles must be integrally fixed, and two rubber o-rings are set as the static seal between static magnetic pole and inner sleeve, complex structure, sealing effect is poorer, dispel the heat more difficult (because between two static magnetic poles, and equal Presence of an interface between static magnetic pole and inner core, be unfavorable for heat transfer), and the setting of inner core makes the internal diameter of static magnetic pole increase, thus the diameter of seal ring is also larger, the linear velocity of sealing surface is also larger.
2) with annular permanent magnet 5 is arranged at the middle part of rotary pole 4 and compared with axial charging mode.In this mode, except having 1) in described problem except, also there is following mechanics problem:
First: permanent magnet is brittle material, and tensile strength is low, the huge centrifugal force self produced at high speed also needs to rely on and is born by non-magnetic urceolus, has higher requirement to the structure of urceolus and selection.
Second: permanent magnetism system sinter molding or molding and forming, dimensional accuracy is not high, non-uniform mass, when to be arranged at by permanent magnet 5 on rotary pole 4 along with running shaft 1 High Rotation Speed, affects the dynamic balancing effect of whole rotor-support-foundation system.
3) with annular permanent magnet 5 is arranged at the end of rotary pole 4 and compared with radial magnetizing mode
In this mode, permanent magnet 5 is still arranged on rotary pole 4, and above-mentioned two mechanics problems still exist.
4) compared with annular permanent magnet 5 being arranged at the outer end axial charging mode of rotary pole 4
In this mode, except above-mentioned two mechanics problems, the mechanics problem that also increase by is new:
Axial magnetic pull increases the axial load of high-speed bearing, makes the lost of life of high-speed bearing.
5) compared with annular permanent magnet 5 being arranged at the outer end axial charging mode of static magnetic pole 7
In this mode, also there is the axial load that axial magnetic pull increases high-speed bearing, make the problem of the lost of life of high-speed bearing.
And annular permanent magnet 5 is arranged at the inner end of static magnetic pole 7 and/or outer end and radial magnetizing by the present invention, then completely eliminate above-mentioned all problems.
In order to reduce thickness and the radial dimension of static magnetic pole further, reduce the diameter of static magnetic pole seal ring, thus reduce the linear velocity of seal face, the present invention all arranges the annular permanent magnet of a radial magnetizing at the inner end of static magnetic pole and outer end, and the magnet ring 5 being sheathed on inner end is oppositely arranged in polarity with the magnet ring 5 being sheathed on outer end.
Its principle is: the Magnetic flux density on the seal ring end face of magnetic fluid sealing structure is very large, all near the saturation flux density of pole material.Equal magnetic flux because Magnetic flux density is multiplied by sectional area, and in magnetic circuit, the magnetic flux of each section remains unchanged, so the magnetic flux summation of 6 seal ring end faces equals the magnetic flux that permanent magnet is sent by the end of static magnetic pole.Therefore, the radial cross section of static pole end piece amasss the summation of the face area that must be greater than 6 seal rings, enough magnetic flux could be supplied to 6 seal rings, allow the Magnetic flux density of the end face of 6 seal rings reach capacity, and don't make the Magnetic flux density of static pole end piece saturated prematurely.As all arranged the annular permanent magnet of a radial magnetizing in two ends of static magnetic pole, both polarity is relative, then corresponding 3 seal rings in each end, the radial cross section of the end of static magnetic pole amasss the sectional area compared when only installing permanent magnet an end can reduce half, namely the thickness of static magnetic pole can be thinner, and radial dimension is less.
5, rotary pole 4 is placed in non-vacuum environment, can not only apply to force cooling in static magnetic pole 7 side, can also apply heat transfer by convection, substantially increase the heat dispersion of magnetic fluid movable sealing structure, thus realize effective high speed motive sealing in rotary pole 4 side.
6, static magnetic pole 7 endoporus is provided with guard ring 92, rotary pole 4 can be avoided to follow when running shaft 1 rotates and occurs larger circular runout and static magnetic pole 7 touches mill.
Its principle is: from radial direction, rotor Jun Youliangge center, and one is geometrical center, is decided by machining, and a Ge Shi center of mass, is decided by dynamic balancing, and the dynamic balancing effect of rotor is better, and center of mass is the closer to geometrical center.According to the rule of rotor dynamics, at high speed, rotor has a strong trend of drawing close the center of mass of rotor at the rotating center of radial direction, but due to the existence of bearing radial support rigidity, make rotor at the rotating center of radial direction neither the geometrical center of rotor, neither the center of mass of rotor, but the some points between geometrical center and center of mass, bearing radial support rigidity is less, rotating center is more close to center of mass, the geometrical center of rotor and center of mass all rotate around rotating center, but the turning radius of geometrical center is large, the turning radius of center of mass is little, so the centrifugal force produced by the rotation of center of mass is also little.Because above-mentioned centrifugal force is born by bearing, so the radial pressure in this case suffered by bearing is smaller, bearing wear is less, and the life-span is longer, and mechanical vibration are also smaller.
If increase the radial support rigidity of bearing, such as, make radial support rigidity for infinitely great, the rotating center of rotor will be forced unlimited near geometrical center, and now the turning radius of the geometrical center of rotor is little, and the turning radius of center of mass is large.Due to the High Rotation Speed of center of mass and radius is comparatively large, will produce a larger centrifugal force, this centrifugal force makes bearing bear a huge radial pressure, bearing wear is aggravated, the lost of life, and mechanical vibration are increased.
High speed rotor generally uses flexibly mounted high speed roller bearing, such as at the nested rubber o-ring in high speed roller bearing outer ring, to reduce the radial support rigidity of bearing, the turning radius of the center of mass of rotor is reduced, thus reduce the radial pressure of centrifugal force and bearing, reduce bearing wear, reduce mechanical vibration.
According to the rule of rotor dynamics, at low speeds, such as when rotor starting, the rotating center of rotor is not strong near the trend of the center of mass of rotor, it is larger from the distance of the center of mass of rotor than the rotor rotating center under high-speed case from the distance of center of mass that this just makes the rotor under low-speed situations rotate the heart, and the centrifugal force that the center of mass of low-speed situations lower rotor part is produced around the rotating center rotation of rotor is also larger.But because the radial support rigidity of bearing is smaller, be difficult to resist this centrifugal force, thus rotor is made to produce radial displacement (i.e. circular runout), the center of mass of rotor is made more to depart from rotating center under the influence of centrifugal force, form larger centrifugal force, thus drive whole rotor to form larger circular runout.Therefore the necessary guard ring 92 that arranges is to avoid rotary pole 4 to follow when running shaft 1 rotates and occurs larger circular runout and static magnetic pole 7 touches mill.
Sliding bearing is conventional high-speed bearing; although its power consumption is large, complex structure; but it is wear-resistant; life-span is long; but the radial clearance of sliding bearing is about 0.1mm, close with the seal clearance of magnetic fluid, turn shaft run-out when low speed starts larger; very easily exceed the scope that device for sealing magnetic fluid can bear, need guard ring protection be set.
Electromagnetic bearing is non-contact type bearing, completely without wearing and tearing, is the good substitute of high-speed ball bearing; have larger gap between its rotating shaft and bearing, once electromagnetic bearing lost efficacy, rotor will unstability; produce very large radially wobbling, need guard ring protection be set.
Air hydrodynamic bearing is applicable to using at high speed, and be yielding support, support stiffness is smaller, easily occurs larger circular runout when low speed starts, and need arrange guard ring protection.
Guard ring set by the present invention; the circular runout of running shaft 1 when low speed starts can be avoided excessive; driven rotary magnetic pole 4 touches the seal ring 6 on the static magnetic pole 7 of mill, damages magnetic fluid sealing structure, can adapt to installation environment and the applying working condition of above-mentioned multiple high-speed bearing.
Summary of the invention
Thus the centrifugal force that cannot overcome magnetic fluid itself for existing magnetic fluid movable sealing structure can not bear the problems such as high rotating speed, the invention provides one and be suitable for high-revolving magnetic fluid movable sealing structure, it has good sealing effect, the advantage of excellent heat dissipation performance, can bear the sealing surface linear velocity being greater than 20 meter per seconds.
The technical solution adopted for the present invention to solve the technical problems is:
One is applicable to high-revolving magnetic fluid movable sealing structure, be installed on casing 8, the cylindric rotary pole 4 that it comprises cylindric static magnetic pole 7 and is coaxially sleeved on outside static magnetic pole 7, described static magnetic pole 7 one end is fixed on casing 8, the cylinder outer surface of described static magnetic pole 7 is provided with more than two seal rings 6 given prominence to, running shaft 1 passes from the axle center hole of described static magnetic pole 7 and connects firmly integral with described rotary pole 4, radial clearance between described seal ring 6 and the magnetic conduction internal surface of rotary pole 4 is provided with magnetic fluid 3 and coordinates with the magnetic fluid motive sealing between rotary pole 4 to realize static magnetic pole 7.
As to further improvement of the present invention, described rotary pole 4 comprises the rotating cylinder 2 that magnetic conductive material is made and the non-magnetic coating 42 being arranged at rotating cylinder inwall, axial position corresponding to each seal ring 6 is provided with the annular groove 41 running through non-magnetic coating 42, and described magnetic fluid 3 is wrapped between annular groove 41 and seal ring 6.
As to further improvement of the present invention, the cell wall top of described annular groove 41 is connected with rotary pole 4 internal surface by chamfer surface or arc surface.
As to further improvement of the present invention, the sidewall of described rotary pole 4 is provided with openable magnetic fluid filler port 43, described rotary pole 4 outer surface arranges more than two annular fin 44.
As to further improvement of the present invention, described static magnetic pole 7 is fixed with casing 8 by the radial ring 9 being arranged at its end.
As to further improvement of the present invention, the inner end of described static magnetic pole 7 and/or outer end are arranged with the magnet ring 5 of radial magnetizing, and the magnet ring 5 being sheathed on inner end is oppositely arranged in polarity with the magnet ring 5 being sheathed on outer end.
As to further improvement of the present invention, radial ring 9 inside of described static magnetic pole 7 is provided with cooling medium circulation canal 91 and cooling liquid turnover through hole.
As to further improvement of the present invention, in described static magnetic pole 7 endoporus, be provided with the circular guard ring 92 for limiting running shaft 1 circular runout scope.
As to further improvement of the present invention, in described casing 8 endoporus, be provided with the circular casing guard ring 82 for limiting running shaft 1 circular runout scope.
As to further improvement of the present invention, described casing 8 is provided with cooling medium circulation canal 81.
The invention has the beneficial effects as follows: owing to present invention employs stationary part interior, rotating part outside, and the movable sealing structure that magnetic fluid is wrapped up by non-magnetic annular groove, under high-speed state, effectively utilizing centrifugal force makes magnetic fluid compress the sealing surface of rotary pole, rotating speed is higher, fit tighter, avoid magnetic fluid a large amount of toward external migration from seal clearance, ensure that the magnetic fluid thickness in seal clearance, reach motive sealing effect good under high-speed working condition, its sealing surface can bear the higher line speed being greater than 20 meter per seconds, the present invention has good sealing effect, the advantage of excellent heat dissipation performance.
Accompanying drawing explanation
Fig. 1 is structural representation of the present invention.
Fig. 2 is partial structurtes I schematic diagram in the embodiment of the present invention 1.
Fig. 3 is partial structurtes II schematic diagram in Fig. 2.
Fig. 4 is that in prior art, magnetic fluid movable sealing structure magnetic fluid at high speed distributes and sealing effect figure.
Fig. 5 is that the present invention's magnetic fluid at high speed distributes and sealing effect figure.
Fig. 6 is the present invention's magnetic fluid velocity gradient schematic diagram at high speed.
Fig. 7 is the structural representation of embodiment 2.
Fig. 8 is embodiment 3 structural representation.
Fig. 9 is the structural representation of embodiment 4.
In figure: 1-running shaft, 11-seal ring, 2-rotary pole rotating cylinder, 3-magnetic fluid velocity gradient line at high speed, 31-magnetic fluid high speed velocity gradient line at high speed, 32-magnetic fluid low speed velocity gradient line at high speed, 33-magnetic fluid zero-speed velocity gradient line at high speed, 4-rotary pole, 41-annular groove, the non-magnetic coating of 42-, 43-magnetic fluid hand-hole, 44-annular fin, 5-permanent magnet, 6-seal ring, 7-static magnetic pole, 8-casing, 81-cooling medium circulation canal, 82-guard ring, 83-seal ring, 9-radial ring, 91-cooling medium circulation canal, 92-guard ring.
Embodiment
embodiment 1,one is applicable to high-revolving magnetic fluid movable sealing structure, as shown in Figure 1, Figure 2 and Figure 3.Be installed on casing (8), the cylindric rotary pole 4 that it comprises cylindric static magnetic pole 7 and is coaxially sleeved on outside static magnetic pole 7, described static magnetic pole 7 is fixed with casing 8 by the radial ring 9 being arranged at its end.Particularly, static magnetic pole 7 is rigidly connected with casing 8 by the radial ring 9 being arranged at its end, radial ring 9 is fixedly installed on casing 8 and also seals with seal ring 83, and rotary pole 4 is arranged in non-vacuum environment, and the radial ring 9 of static magnetic pole 7 is provided with cooling medium circulation canal 91.
The cylinder outer surface of described static magnetic pole 7 is provided with the outstanding cylndrical surface seal ring 6 of more than two, and the quantity of cylndrical surface seal ring 6 according to seal request quantity setting routinely, in the present embodiment can be 6.Running shaft 1 passes from the axle center hole of described static magnetic pole 7, is rigidly connected and is sealed by seal ring 11 with described rotary pole 4.
Radial clearance between described seal ring 6 and the internal surface of rotary pole 4 is provided with magnetic fluid 3 and coordinates with the motive sealing between rotary pole 4 to realize static magnetic pole 7.Particularly, described rotary pole 4 comprises the rotating cylinder 2 that magnetic conductive material is made and the non-magnetic coating 42 being arranged at rotating cylinder 2 inwall, axial position corresponding to each seal ring 6 is provided with the annular groove 41 running through non-magnetic coating 42, therefore, do not isolated by non-magnetic coating between described seal ring 6 and the internal surface of rotating cylinder 2, radial clearance between seal ring 6 and rotating cylinder 2 internal surface is filled by magnetic fluid 3, and namely magnetic fluid 3 is wrapped between annular groove 41 and seal ring 6.
The cell wall top of described annular groove 41 is connected with rotary pole 4 internal surface by chamfer surface or arc surface.Particularly, described annular groove 41 liang of cell walls are connected the inner cylindrical surface of non-magnetic coating 42 by chamfer surface or arc surface.The sidewall of described rotary pole 4 is provided with openable, corresponding to the magnetic fluid filler port 43 of each seal ring 6.Each filler port 43 outer end seal ring seals, each filler port 43 radially stagger several angle distribution.
The inner end of described static magnetic pole 7 and outer end are arranged with the magnet ring 5 of radial magnetizing, and the magnet ring 5 being sheathed on inner end is oppositely arranged in polarity with the magnet ring 5 being sheathed on outer end.As shown in Figure 1.
Be provided with the circular guard ring 92 for limiting running shaft 1 circular runout scope in the endoporus of described static magnetic pole 7, the material of described circular guard ring 92 can be conventional material of the prior art, as beryllium bronze.
Working procedure of the present invention is:
After each for magnetic fluid sealing structure of the present invention parts being correctly assembled into one, open each filler port 43 and to annotate magnetic fluid, under static state, magnetic fluid is full of among whole air-gap field (i.e. seal clearance), and its cross section is rectangle, and now sealing effect is good.As shown in figure 1, figure 2 and figure 3.
Under high-speed state, owing to present invention employs static magnetic pole 7 interior, rotary pole 4 movable sealing structure outside, when rotary pole 4 rotates, magnetic fluid 3 is driven to rotate, the centrifugal force that magnetic fluid 3 is produced acts directly on (namely bottom annular groove 41) on the inner seal face of rotary pole 4, flow toward both sides in the bottom of this centrifugal force pulls magnetic fluid 3 annularly groove 41, owing to being subject to the stop of two sidewalls of annular groove 41, magnetic fluid 3 sidewall of annularly groove 41 can only climb (namely radially near axis of rotation) from bottom land toward groove top, due to sidewall and rotary pole 4 synchronous rotary of annular groove 41, magnetic fluid is herein made also to produce outside centrifugal force, the sidewall of this centrifugal force pulls magnetic fluid annularly groove 41 flows (namely radially away from axis of rotation) from groove top toward bottom land, thus greatly reduce the magnetic fluid 3 annularly sidewall of groove 41 phenomenon of climbing toward groove top from bottom land under centrifugal action, effectively limit magnetic fluid 3 a large amount of phenomenon toward external migration from seal clearance at high speed, ensure that in seal clearance have enough magnetic fluids to play seal action, ensure that the motive sealing effect under high rotating speed.As shown in Figure 5.
Its mechanics principle is:
Running shaft 1 driven rotary magnetic pole 4 High Rotation Speed of High Rotation Speed, the rotary pole 4 of High Rotation Speed drives magnetic fluid 3 High Rotation Speed, and form a velocity gradient in magnetic fluid inside, more close to bottom and the sidewall of the annular groove 41 of rotary pole 4, magnetic fluid rotating speed is higher, more close to seal ring 6, magnetic fluid rotating speed is lower.As shown in Figure 6.
The High Rotation Speed of magnetic fluid itself, makes the centrifugal force that its inner generation is very large.This centrifugal field is similar to a gravity field, the acceleration A=v of centrifugal field
2/ r, direction along running shaft radial direction outwardly.When the linear velocity of magnetic fluid motive sealing is v=20 meter per second, during turning radius r=10mm, A=4000g, i.e. 4000 times of gravity accleration, speed is higher, and A value is larger, even up to tens thousand of times of gravity accleration.
Magnetic fluid in seal clearance:
If seal ring 6 is H to the distance of the bottom of annular groove 41, the rotating speed of rotary pole is VH, then radially the rotating speed V of magnetic fluid is that it arrives the monotonically increasing function of the distance h of seal ring 6, i.e. V=f(h), and h
1<h
2time, V
h1<V
h2, therefore
When being close to seal ring 6, h=0, V
0=f(0)=0; When being close to the bottom of annular groove 41, h=H, V
h=f(H)=V
h.
Gravity field makes liquid level be the liquid of H
, this is due to the acceleration g of gravity field and the irrelevant constant of liquid level h.And the acceleration of centrifugal field herein
the monotonically increasing function of liquid level h, so centrifugal force herein makes magnetic fluid in seal clearance to the pressure produced bottom annular groove 41
, namely
.
The magnetic fluid of annular groove 41 sidewall:
As shown in Figure 6, the rotating speed of magnetic fluid is herein VH, and has nothing to do with the distance H bottom seal ring 6 to annular groove 41, thus its from radial direction to bottom annular groove 41 produce pressure
.
As can be seen here, toward the both sides flowing bottom annular groove 41 and annularly strength (the i.e. P that climbs toward groove top of groove 41 sidewall under centrifugal action of the magnetic fluid in seal clearance
sealing), be less than magnetic fluid annularly strength (i.e. P of flowing toward bottom land of groove 41 sidewall under centrifugal action
sidewall), and rotating speed is higher, and this strength difference is larger, even if this guarantees magnetic fluid under very high rotating speed, also toward external migration in seal clearance, thus can not ensure that sealing effect.
embodiment 2,with embodiment 1, difference is: be provided with the circular casing guard ring 82 for limiting running shaft 1 circular runout scope in described casing 8 endoporus, described casing 8 is provided with cooling medium circulation canal 81.
As shown in Figure 7, when described guard ring 82 is for preventing running shaft 1 circular runout larger, driven rotary magnetic pole 4 touches the seal ring 6 on the static magnetic pole 7 of mill, damages magnetic fluid sealing structure.
embodiment 3,rotary pole 4 is placed in vacuum and installs to meet the use needs having special operation condition.As shown in Figure 8, described rotary pole 4 is placed in the vacuum environment closed by flange and casing 8.
embodiment 4,with embodiment 1,9 annular fin 44 are set at the outer surface of rotary pole 4, to strengthen heat radiation further.As shown in Figure 9.
The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, all any amendments done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should be included within protection scope of the present invention.
Claims (10)
1. one kind is applicable to high-revolving magnetic fluid movable sealing structure, be installed on casing (8), it is characterized in that: it comprises cylindric static magnetic pole (7) and is coaxially sleeved on static magnetic pole (7) cylindric rotary pole (4) outward, described static magnetic pole (7) one end is fixed on casing (8), the cylinder outer surface of described static magnetic pole (7) is provided with more than two seal rings (6) given prominence to, running shaft (1) passes from the axle center hole of described static magnetic pole (7) and connects firmly integral with described rotary pole (4), radial clearance between described seal ring (6) and the magnetic conduction internal surface of rotary pole (4) is provided with magnetic fluid (3) and coordinates with the magnetic fluid motive sealing realized between static magnetic pole (7) with rotary pole (4).
2. be applicable to high-revolving magnetic fluid movable sealing structure according to claim 1, it is characterized in that: described rotary pole (4) comprises the rotating cylinder (2) that magnetic conductive material is made and the non-magnetic coating (42) being arranged at rotating cylinder inwall, axial position corresponding to each seal ring (6) is provided with the annular groove (41) running through non-magnetic coating (42), and described magnetic fluid (3) is wrapped between annular groove (41) and seal ring (6).
3. be applicable to high-revolving magnetic fluid movable sealing structure according to claim 1, it is characterized in that: the cell wall top of annular groove (41) is connected with rotary pole (4) internal surface by arc surface or chamfer surface.
4. be applicable to high-revolving magnetic fluid movable sealing structure according to claim 1, it is characterized in that: the sidewall of described rotary pole (4) is provided with openable magnetic fluid filler port (43), described rotary pole (4) outer surface arranges more than two annular fin (44).
5. be applicable to high-revolving magnetic fluid movable sealing structure according to claim 1, it is characterized in that: described static magnetic pole (7) is fixed with casing (8) by the radial ring (9) being arranged at its end.
6. be applicable to high-revolving magnetic fluid movable sealing structure according to claim 5, it is characterized in that: the inner end of described static magnetic pole (7) and outer end are arranged with the magnet ring (5) of radial magnetizing, the magnet ring (5) being sheathed on inner end and the magnet ring (5) being sheathed on outer end are oppositely arranged in polarity.
7. being applicable to high-revolving magnetic fluid movable sealing structure according to claim 1, it is characterized in that: in described static magnetic pole (7) endoporus, being provided with the circular guard ring (92) for limiting running shaft (1) circular runout scope.
8. be applicable to high-revolving magnetic fluid movable sealing structure according to claim 5, it is characterized in that: the radial ring (9) of described static magnetic pole (7) is provided with internal cooling medium circulation passage (91).
9. being applicable to high-revolving magnetic fluid movable sealing structure according to claim 1, it is characterized in that: in described casing (8) endoporus, being provided with the circular casing guard ring (82) for limiting running shaft (1) circular runout scope.
10. be applicable to high-revolving magnetic fluid movable sealing structure according to claim 1, it is characterized in that: described casing (8) has casing cooling medium circulation canal (81).
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| CN106321854A (en) * | 2016-10-21 | 2017-01-11 | 北京交通大学 | Magnetic liquid sealing device with radial isodirectional magnetization of permanent magnets |
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| CN104455463B (en) * | 2014-08-06 | 2015-09-30 | 北京交通大学 | Embed the cooling liquid formula magnetic fluid seal device of heat-conducting plate |
| CN108413043A (en) * | 2018-06-12 | 2018-08-17 | 邵阳市达力电源实业有限公司 | Blender device for sealing magnetic fluid |
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| CN112758291A (en) * | 2021-01-27 | 2021-05-07 | 武汉波依迈科技有限公司 | High-power sealed rim propeller |
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| JPS59147162A (en) * | 1983-02-09 | 1984-08-23 | Mitsubishi Electric Corp | Magnetic fluid seal device |
| JP3256449B2 (en) * | 1996-10-24 | 2002-02-12 | エヌオーケー株式会社 | Sealing device using magnetic fluid |
| CN2320848Y (en) * | 1997-12-05 | 1999-05-26 | 中国矿业大学 | Magnetic fluid sealing device |
| US6543782B1 (en) * | 2001-04-11 | 2003-04-08 | Ferrotec (Usa) Corporation | Non-bursting ferrofluid seal |
| CN102537367B (en) * | 2012-01-12 | 2014-12-03 | 北京理工大学 | Shaft sealing device with magnetic fluids |
| CN203335868U (en) * | 2013-06-25 | 2013-12-11 | 南京旋妙机械设备有限公司 | Magnetic fluid motive seal structure suitable for high rotary speed |
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2013
- 2013-06-25 CN CN201310252516.0A patent/CN103343821B/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106321854A (en) * | 2016-10-21 | 2017-01-11 | 北京交通大学 | Magnetic liquid sealing device with radial isodirectional magnetization of permanent magnets |
| CN106321854B (en) * | 2016-10-21 | 2018-02-16 | 北京交通大学 | The magnetic fluid seal device that permanent magnet radially magnetizes in the same direction |
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|---|---|
| CN103343821A (en) | 2013-10-09 |
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Denomination of invention: Magnetofluid motive sealing structure suitable for high rotation speed Effective date of registration: 20160808 Granted publication date: 20150916 Pledgee: Zhuzhou Tianyuan Guoxin wealth micro loan Co., Ltd. Pledgor: Nanjing Xuanmiao Mechanical Machinery Co., Ltd. Registration number: 2016430000023 |
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