CN112849380A

CN112849380A - Contra-rotating sealing assembly and contra-rotating propeller adopting same

Info

Publication number: CN112849380A
Application number: CN202110082091.8A
Authority: CN
Inventors: 王前进
Original assignee: Wuhan Boymai Technology Co ltd
Current assignee: Wuhan Boymai Technology Co ltd
Priority date: 2021-01-21
Filing date: 2021-01-21
Publication date: 2021-05-28

Abstract

The invention discloses a contra-rotating seal assembly, which comprises a shaft hub and a shaft sleeve, wherein the shaft hub and the shaft sleeve are respectively used for being connected to a pair of components which rotate in opposite directions; the shaft hub is wrapped on the shaft sleeve and is connected with the shaft sleeve through a bearing; the side edge of the bearing is provided with a salient pole and a concave pole; the concave pole is provided with a U-shaped or V-shaped groove, and is connected with the permanent magnet into a whole and fixed in the shaft hub; the salient poles are fixed on the shaft sleeve, the tops of the salient poles are arranged in the grooves, and U-shaped or V-shaped gaps are formed between the salient poles and the grooves; magnetic fluid is filled in the gap; the magnetic fluid is accumulated at the bottom of the groove under the action of a radial magnetic field provided by the permanent magnet right above the outer side of the concave pole, and a U-shaped or V-shaped sealing belt is formed between the salient pole and the concave pole by utilizing the principle of static pressure balance of the fluid in the U-shaped pipe. The invention provides a contra-rotating sealing assembly with self-adjustability and suitable for high rotating speed and a contra-rotating propeller adopting the assembly.

Description

Contra-rotating sealing assembly and contra-rotating propeller adopting same

Technical Field

The invention belongs to the field of mechanical engineering sealing, and particularly relates to a self-adjusting sealing structure suitable for high rotating speed and a counter-rotating propeller adopting the counter-rotating sealing assembly.

Technical Field

In recent years, with the needs of national defense construction of navy and the development of water trade, the performance requirements on ship propulsion devices are higher and higher, the disadvantages of the traditional shaft-driven propellers are gradually highlighted, the working requirements cannot be better met, people gradually turn eyes to more advanced shaftless propulsion systems, contra-rotating propellers are also developed for improving the propulsion efficiency, two common propellers are respectively arranged in two concentric hollow rotating shafts and rotate in opposite directions of constant speed or unequal speed.

Chinese patent 'contra-rotating shaftless rim drive propeller' (CN105109650B) discloses a contra-rotating propeller, which adopts a sliding bearing, utilizes seawater to cool a motor, is suitable for an environment with better water quality, but for a turbid environment with more sand grains, if the sealing protection treatment is not carried out on the bearing and the contra-rotating connection part of a front rotating shaft and a rear rotating shaft, the sand grains entering a gap can seriously affect the performance and the service life of parts, thus a contra-rotating sealing part capable of bearing radial load and axial load simultaneously is needed, and magnetic fluid is taken as a special functional material and is applied to various fields at present, wherein the contra-rotating propeller is a colloid system formed by uniformly dispersing ferromagnetic grains in carrier liquid, has strong magnetism and fluidity, can keep stable for a long time under the action of various forces such as gravity, magnetic force and the like, does not generate precipitation and layering, and plays a great role in mechanical sealing, the magnetic fluid seal has the following advantages: 1. the sealing performance is good and the repair is easy; 2. no abrasion, long service life and low power consumption; 3. simple structure, with low costs, the reliability is high, but current magnetic current body dynamic seal, utilize the magnetic current body to receive the axial magnetic pulling force restraint of two magnetic poles in the middle of the magnetic circuit clearance that static magnetic pole and rotatory magnetic pole formed, form sealedly, in operation process, the magnetic current body produces radial centrifugal force outwards because rotatory on the rotating surface, the magnetic current body in the operation process can shake off the influence of the constraint of magnetic force and take place the cave in because of the effect of centrifugal force, the effective seal thickness that leads to magnetic current body "O type sealing washer" obviously reduces, the sealing performance worsens, when being in high-speed operation in-process, can lead to sealed the inefficacy even.

Disclosure of Invention

In view of the defects of the prior art, the invention provides a contra-rotating sealing assembly with self-adjustment and suitability for high rotating speed and a contra-rotating propeller adopting the assembly.

In order to achieve the purpose, the invention adopts the technical scheme that:

a contra-rotating seal assembly comprises a shaft hub and a shaft sleeve which are respectively used for being connected to a pair of components rotating in opposite directions; the shaft hub is wrapped on the shaft sleeve and is connected with the shaft sleeve through a bearing; the side edge of the bearing is provided with a salient pole and a concave pole; the concave pole is provided with a U-shaped or V-shaped groove, and is connected with the permanent magnet into a whole and fixed in the shaft hub; the salient poles are fixed on the shaft sleeve, the tops of the salient poles are arranged in the grooves, and U-shaped or V-shaped gaps are formed between the salient poles and the grooves; magnetic fluid is filled in the gap; the magnetic fluid is accumulated at the bottom of the groove under the action of a radial magnetic field provided by a permanent magnet right above the outer side of the concave pole, and a U-shaped or V-shaped sealing strip is formed between the salient pole and the concave pole by utilizing the principle of static pressure balance of fluid in the U-shaped pipe; the beneficial effects are that: the bearing has good bearing capacity and rotation precision as the existing part, a gap with a U-shaped section is formed by the structural forms of the salient pole and the concave pole, and magnetic fluid is filled in the gap; the magnetic poles on the inner side of the permanent magnet provide a radial magnetic field for the magnetic fluid in a close distance, so that the two ends of the magnetic fluid generate a potential energy moving radially outwards, the magnetic fluid is further promoted to be accumulated at the bottom of the groove to form a sealing strip, the static pressure balance of the fluid in the U-shaped pipe is realized, the sealing strip is wholly deviated to achieve new balance under the condition that the pressure difference exists between the two ends of the magnetic fluid, the sealing surface cannot be damaged, and the sealing effect is not influenced; when the salient pole or the concave pole in a rotating state drives the magnetofluid to rotate, the magnetofluid can generate centrifugal force, the direction of the centrifugal force is also outward in the radial direction, the magnetofluid enhances the potential accumulated to the bottom of the concave pole under the equidirectional superposition effect of the magnetic force and the centrifugal force, according to the principle of static pressure balance of the fluid in the U-shaped tube, the pressure difference between two ends of the magnetofluid is zero, when the pressure difference is not zero, the magnetofluid can be wholly deviated in a gap to form liquid level height difference between two ends, so that the balanced pressure difference is realized, the higher the rotating speed is, the larger the centrifugal force is, the extremely small liquid level height difference can resist extremely strong external pressure difference, the extremely good dynamic sealing effect can be ensured, the problem that the sealing thickness is stretched and thinned and punctured due to the influence of the centrifugal force of the magnetofluid in a high-speed state is not worried about, the stronger the capacity of resisting the external pressure difference, the more suitable the working condition that the external pressure difference increases along with the increase of the rotating speed, and the self-regulation capacity is strong.

Preferably, a carrier liquid strip for increasing the contact area with the magnetic fluid is arranged in the gap, and the carrier liquid strip is bonded on the concave electrode; the beneficial effects are that: the liquid carrying bar is used as an extension part of the concave pole or the convex pole, so that the surface contact area of the concave pole or the convex pole and the magnetic fluid is indirectly increased, the capacity of the concave pole or the convex pole for driving the magnetic fluid to rotate is enhanced, the magnetic fluid can obtain more energy to rotate, and a larger centrifugal force is generated; the carrier liquid bar can be made of a material with a sponge structure, such as high-density sponge, and is mainly characterized by flexibility and porosity, fluid can freely shuttle in pores of the carrier liquid bar without affecting the fluidity of the carrier liquid bar and further without affecting the sealing effect of the fluid, and more importantly, the sponge structure of the carrier liquid bar is criss-cross, so that the capacity of the rotating part for driving the magnetic fluid to rotate is greatly increased; in general, the carrier strip may be replaced with batt fiber or down for cost savings.

Preferably, the permanent magnet is in an annular structure, is magnetized by radiation and is a monopole radiation ring; the beneficial effects are that: the magnetic poles of the monopole radiation ring are respectively positioned at the inner side and the outer side, as is known, the magnetic poles are the parts with the strongest magnetic force in the magnet, the magnetic induction lines are distributed most densely, the magnetic field lines which are closer to the magnetic poles at the inner side of the annular permanent magnet are in a radial distribution state, the grooves are tightly attached to the magnetic poles at the inner side of the annular permanent magnet and are positioned at the center, so that the whole magnetic fluid sealing strip is positioned at the optimal position where the magnetic poles provide the magnetic field in a short distance, the maximum radial magnetic force can be obtained, the magnetic fluid is further promoted to be accumulated at the bottom of the grooves to form the sealing strip, the static. The permanent magnet can be formed by combining a plurality of fan-shaped permanent magnets in a staggered manner, a radiation ring can be adopted for the annular permanent magnet with a small radius, the processing is easy, but the processing is not easy for the annular permanent magnet with a large diameter, and the processing difficulty can be reduced by adopting a combined manner; in order to make the magnetic field distribution more uniform, the sector permanent magnets are arranged in a staggered manner, and a radiation magnetizing or radial magnetizing mode is adopted.

Preferably, the permanent magnet and the concave pole are connected into a whole and fixed on the shaft sleeve through the rotating ring, and the salient pole is fixed on the shaft sleeve; the beneficial effects are that: the permanent magnet and the concave pole are connected into a whole to further shorten the distance between the magnetic pole and the magnetic fluid, so that the magnetic fluid can obtain larger magnetic force and generate stronger sealing performance; the concave pole is fixed on the rotating component, on one hand, the magnetic fluid is accumulated towards the bottom of the groove under the action of a magnetic field, the magnetic particles in the magnetic fluid are distributed unevenly under the action of the magnetic field, the concentration of the magnetic particles is denser at the part closer to the magnetic pole, and further the part closer to the magnetic pole is, the viscosity of the magnetic fluid is higher, compared with the salient pole, the concave pole rotates to drive the magnetic fluid to obtain centrifugal force, so that the sealing performance is higher in a dynamic sealing state, and the viscosity of the magnetic fluid close to the salient pole is small, the friction force between the magnetic fluid and the salient pole is small during rotation, and the heat generated during operation is relatively small; on the other hand, in the sealing structure, the concave part is arranged at the outer ring of the salient pole, the surface contact area of the concave pole and the magnetic fluid is larger than that of the salient pole and the magnetic fluid, the generated static friction force is large, the transmitted energy is large, the capacity of driving the magnetic fluid to rotate is better than that of the salient pole, and in the rotating process, the speed of the concave pole line at the outer ring is larger than that of the salient pole at the inner ring, the generated centrifugal force is larger, and the resistance to external pressure difference is better facilitated; the concave pole is preferably made of flexible materials, such as high-elasticity polymers with strong plasticity, more specifically polytetrafluoroethylene, which is resistant to high temperature and low temperature, and when the concave pole is made of flexible materials, the annular permanent magnet can be used as a support to provide powerful support for the concave pole, so that the concave pole is ensured not to deform during high-speed operation, the sealing effect is further ensured, and the number of parts is reduced; it is especially pointed out that, because the magnetic poles of the permanent magnet are respectively positioned at the inner side and the outer side, the inner side magnetic pole provides a magnetic field for the magnetic fluid, and the outer side magnetic pole can also provide a magnetic field, if a U-shaped gap is formed in the outer space of the permanent magnet, the magnetic grease can be filled in the non-Newtonian magnetic fluid with high viscosity and low cost, and an auxiliary sealing strip is formed under the action of centrifugal force.

Preferably, the permanent magnet and the concave pole are connected into a whole and fixed on the shaft hub, and the salient pole is fixed on the shaft sleeve; the beneficial effects are that: the permanent magnet and the concave pole are directly connected into a whole and fixed on the shaft hub by utilizing the contra-rotating motion characteristics of the shaft sleeve and the shaft hub, and the convex pole is fixed on the shaft sleeve, so that the number of parts can be reduced, the installation difficulty is reduced, and the cost is saved.

Preferably, an oil slinger is arranged at the side end of the salient pole, the oil slinger is fixed on the shaft sleeve, and a labyrinth type sealing structure is arranged between the oil slinger and the shaft sleeve; the beneficial effects are that: the oil slinger and the concave pole form a labyrinth type sealing structure, a U-shaped gap is formed at the periphery of the permanent magnet, lubricating grease can be filled in the gap, preferably magnetic lubricating grease, the centrifugal effect generated when the oil slinger operates and the strong magnetic attraction of the magnetic pole of the permanent magnet to the magnetic lubricating grease are fully utilized to form auxiliary sealing, and the sealing performance is improved; the labyrinth seal structure further strengthens the sealing performance of the shaft hub between the shaft sleeves, and effectively prevents impurities from entering.

Furthermore, a stuffing box is arranged at the butt joint gap between the shaft hub and the shaft sleeve; the beneficial effects are that: and impurities are prevented from entering to influence the sealing performance of the magnetic fluid sealing tape.

Preferably, an isolating ring and a mud throwing ring are sequentially arranged at the side end of the oil slinger from inside to outside, the isolating ring is fixed on the shaft hub, and the mud throwing ring is fixed on the shaft sleeve; the beneficial effects are that: in the comparatively abominable condition of operational environment meter, utilize the rotatory mud ring that gets rid of high-speed can throw away large granule impurity such as silt of aquatic, avoid impurity to get into the fluid seal area in, influence sealing performance.

Preferably, the edge of the concave pole is in contact with the salient pole to form a closed space, and the magnetic fluid is limited in the closed space of a U shape or a V shape formed between the salient pole and the concave pole; the beneficial effects are that: on one hand, the magnetic fluid can be prevented from being greatly leaked out when the magnetic fluid is separated from the constraint of magnetic force during violent vibration; on the other hand, the magnetic fluid sealing device can prevent external impurities from entering the magnetic fluid to influence the characteristics of the magnetic fluid and ensure the sealing effect.

A contra-rotating propeller comprises a shell, a front guide pipe and a rear guide pipe; the front guide pipe and the rear guide pipe are movably butted through a contra-rotating sealing assembly according to any one of claims 1 to 8, and the front guide pipe and the rear guide pipe which are connected into a whole are fixed in end covers at two sides of the shell through bearing assemblies; propellers are fixedly arranged in the inner rings of the front guide pipe and the rear guide pipe; a driving device is arranged in a space between the front guide pipe and the shell and between the rear guide pipe and the shell, and the driving device provides power for realizing the mutual reverse rotation of the front guide pipe and the rear guide pipe; the beneficial effects are that: by utilizing the low friction coefficient and high sealing performance of the contra-rotating sealing assembly, the power output of the propeller is improved, and the friction heating is reduced.

Compared with the prior art, the invention has the beneficial effects that: 1. the contra-rotating sealing assembly combines good bearing capacity and rotation precision of the bearing, realizes sealing protection by utilizing the unique property of the magnetic fluid, and ensures that the performance and the service life of the contra-rotating sealing assembly are not influenced by the environment; 2. the method for sealing the magnetic fluid by binding the magnetic fluid in the air gap of the magnetic circuit through axial magnetic tension in the conventional method is broken through, the magnetic fluid is applied with a magnetic force which faces outwards in the radial direction, and the magnetic fluid is promoted to form a U-shaped sealing strip by utilizing the principle of static pressure balance of the fluid in a U-shaped pipe, so that the sealing strip not only ensures the characteristic of a low friction pair of the magnetic fluid, but also eliminates the risk of sealing failure caused by the action of centrifugal force of the magnetic fluid; 3. the centrifugal force is changed from the harmful surface to the beneficial surface, the higher the rotating speed is, the larger the centrifugal force is, the stronger the sealing effect is, the underwater propeller is particularly suitable for being applied, and the self-adjustment performance is strong; 4. the counter-rotating propeller adopting the counter-rotating sealing assembly has low friction power consumption, high efficiency and excellent waterproofness, and can be well adapted to severe environments.

Drawings

FIG. 1 is a schematic structural view of a contra-rotating seal assembly according to a first embodiment;

FIG. 2 is a schematic view of an equilibrium state of the counter rotating seal assembly in the presence of a differential pressure according to the first embodiment;

FIG. 3 is a schematic structural view of the counter-rotating seal assembly according to the second embodiment;

FIG. 4 is a schematic structural view of the contra-rotating seal assembly according to the third embodiment;

FIG. 5 is a schematic structural view of a counter-rotating seal assembly according to a fourth embodiment;

FIG. 6 is a schematic structural view of a counter-rotating seal assembly according to the fifth embodiment;

FIG. 7 is a schematic structural view of a contra-rotating propeller according to the sixth embodiment;

in the figure: 1. a hub; 2. a shaft sleeve; 3. a bearing; 4. a permanent magnet; 41. a secondary permanent magnet; 5. salient poles; 6. a concave pole; 7. a magnetic fluid; 8. carrying a liquid bar; 9. an oil slinger; 10. lubricating grease; 11. a stuffing box; 12. adjusting the gasket; 13. an isolating ring; 14. throwing mud rings; 15. a front motor stator; 16. a rear motor stator; 17. a front motor rotor; 18. a rear motor rotor; 19. a front conduit; 20. a rear duct; 21. a front propeller; 22. a rear propeller; 23. a front end cover; 24. a rear end cap; 25. a rotating ring; 26. a housing.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

As shown in fig. 1-2, a counter-rotating seal assembly includes a hub 1 and a sleeve 2, which are respectively connected to a pair of components rotating in opposite directions; the shaft hub 1 is wrapped on the shaft sleeve 2 and is connected with the shaft sleeve 2 through a bearing 3; the inner end of the bearing 3 is provided with a salient pole 5 and a concave pole 6, the concave pole 6 is provided with a U-shaped groove and is connected with the permanent magnet 4 into a whole to be fixed on the shaft hub 1; the permanent magnet 4 is of an annular structure, is magnetized by radiation and is a monopole radiation ring, and the concave pole 6 is formed by injection molding of a flexible material; an adjusting gasket 12 is arranged between the bearing 3 and the permanent magnet 4; the salient pole 5 is fixed on the shaft sleeve 2, the top of the salient pole is arranged in the groove, and a U-shaped gap is formed between the salient pole and the groove; the gap is filled with magnetic fluid 7; the magnetic fluid 7 is accumulated at the bottom of the groove under the action of a radial magnetic field provided by the permanent magnet 4 right above the outer side of the concave pole 6, and a U-shaped sealing belt is formed between the salient pole 5 and the concave pole 6 by utilizing the principle of static pressure balance of fluid in a U-shaped pipe; in the running state, the magnetic fluid 7 is driven by the concave electrode 6 to rotate, so that the magnetic fluid 7 generates a radial outward centrifugal force; the magnetic fluid 7 is accumulated at the U-shaped bottom of the concave electrode 6 under the combined action of centrifugal force and magnetic force; in order to increase the capacity of the concave electrode 6 for driving the magnetic fluid 7 to rotate, the carrier liquid strip 8 is bonded on the inner surface of a U-shaped groove of the concave electrode 6; an oil slinger 9 is arranged at the inner end of the permanent magnet 4, and the oil slinger 9 is fixed on the shaft sleeve 2 and rotates along with the shaft sleeve; a gap between the oil slinger 9 and the permanent magnet 4 is filled with magnetic lubricating grease 10; in order to increase the sealing performance of the structure, the end surface of the oil slinger 9 and the shaft hub 1 form labyrinth type seal; in order to prevent impurities from entering the sealing structure, a packing box 11 is arranged at the contact axial gap between the shaft hub 1 and the shaft sleeve.

According to the static pressure balance principle of the U-shaped pipe, the magnetic fluid 7 keeps balance under the action of magnetic force in a static sealing state; if there is no pressure difference at the two ends of the magnetic fluid 7, the height difference h of the liquid level at the two ends is zero, if the pressure at one end is increased, the magnetic fluid 7 will wholly shift to the side with low pressure until a new balance state is reached, at this time, the height difference h of the liquid level is formed, and the magnetic fluid 7 in the height difference band balances the external pressure difference under the action of magnetic force; in a dynamic sealing state, the magnetic fluid 7 in a rotating state is acted by magnetic force and centrifugal force, the magnetic fluid and the centrifugal force are mutually superposed to provide a radial force field together to realize the static pressure balance of the U-shaped pipe, the higher the rotating speed is, the larger the centrifugal force is, the extremely small liquid level height difference h can resist extremely strong external pressure difference change, the excellent dynamic sealing effect is ensured, and the problem that the sealing is invalid due to the fact that the magnetic fluid 7 is thinned and punctured is not needed to be worried about; the magnetic lubricating grease 10 is adsorbed on the outer magnetic pole under the action of the permanent magnet 4 and is not easy to leak; when rotating, the oil slinger 9 drives the magnetic lubricating grease 10 to generate centrifugal force, and primary sealing is formed in the gap.

Example two

As shown in fig. 3, a contra-rotating seal assembly comprises a hub 1 and a sleeve 2, which are respectively used for connecting a pair of components rotating in opposite directions; the shaft hub 1 is wrapped on the shaft sleeve 2 and is connected with the shaft sleeve 2 through a bearing 3; the inner end of the bearing 3 is provided with a salient pole 5 and a concave pole 6, the concave pole 6 is provided with a V-shaped groove and is connected with the permanent magnet 4 into a whole to be fixed on the shaft hub 1; the permanent magnet 4 is of an annular structure, is magnetized by radiation and is a monopole radiation ring, and the concave pole 6 is formed by injection molding of a flexible material; an adjusting gasket 12 is arranged between the bearing 3 and the permanent magnet 4; the salient pole 5 is fixed on the shaft sleeve 2, the top of the salient pole is arranged in the groove, and a V-shaped gap is formed between the salient pole and the groove; the gap is filled with magnetic fluid 7; the magnetic fluid 7 is accumulated at the bottom of the groove under the action of a radial magnetic field provided by the permanent magnet 4 right above the outer side of the concave pole 6, and a V-shaped sealing belt is formed between the salient pole 5 and the concave pole 6 by utilizing the principle of static pressure balance of fluid in a U-shaped pipe; in the running state, the magnetic fluid 7 is driven by the concave electrode 6 to rotate, so that the magnetic fluid 7 generates a radial outward centrifugal force; the magnetic fluid 7 is accumulated at the U-shaped bottom of the concave electrode 6 under the combined action of centrifugal force and magnetic force; in order to increase the capacity of the concave electrode 6 for driving the magnetic fluid 7 to rotate, the carrier liquid strip 8 is bonded on the inner surface of a U-shaped groove of the concave electrode 6; an oil slinger 9 is arranged at the inner end of the permanent magnet 4, and the oil slinger 9 is fixed on the shaft sleeve 2 and rotates along with the shaft sleeve; a gap between the oil slinger 9 and the permanent magnet 4 is filled with magnetic lubricating grease 10; for solving the problem of silt in adverse circumstances, oil slinger 9 is inner by inside to outside being equipped with isolating ring 13 and getting rid of mud ring 14, isolating ring 13 is fixed on shaft hub 1, get rid of mud ring 14 and fix on axle sleeve 2, when rotatory respectively, the centrifugal force of production will get into the silt in the clearance and throw away.

EXAMPLE III

As shown in fig. 4, a contra-rotating seal assembly comprises a hub 1 and a sleeve 2, which are respectively used for connecting a pair of components rotating in opposite directions; the shaft hub 1 is wrapped on the shaft sleeve 2 and is connected with the shaft sleeve 2 through a bearing 3; the inner end of the bearing 3 is provided with a salient pole 5 and a concave pole 6, the concave pole 6 is provided with a V-shaped groove and is connected with the permanent magnet 4 into a whole to be fixed on the shaft hub 1; the permanent magnet 4 is of an annular structure, is magnetized by radiation and is a monopole radiation ring, and the concave pole 6 is formed by injection molding of a flexible material; an adjusting gasket 12 is arranged between the permanent magnet 4 and the bearing 3; the salient pole 5 is fixed on the shaft sleeve 2, the top of the salient pole is arranged in the groove, and a V-shaped gap is formed between the salient pole and the groove; the gap is filled with magnetic fluid 7; the magnetic fluid 7 is accumulated at the bottom of the groove under the action of a radial magnetic field provided by the permanent magnet 4 right above the outer side of the concave pole 6, and a V-shaped sealing belt is formed between the salient pole 5 and the concave pole 6 by utilizing the principle of static pressure balance of fluid in a U-shaped pipe; in the running state, the magnetic fluid 7 is driven by the concave electrode 6 to rotate, so that the magnetic fluid 7 generates a radial outward centrifugal force; the magnetic fluid 7 is accumulated at the U-shaped bottom of the concave electrode 6 under the combined action of centrifugal force and magnetic force; in order to reduce the external impurities entering the sealing tape and the leakage of the magnetic fluid 7 during severe vibration, the edge part of the concave pole 6 is slightly contacted with the salient pole 5 to form a closed space, and the magnetic fluid 7 is sealed between the salient pole 5 and the concave pole 6; in order to increase the capacity of the concave electrode 6 for driving the magnetic fluid 7 to rotate, the carrier liquid strip 8 is bonded on the inner surface of a U-shaped groove of the concave electrode 6; an oil slinger 9 is arranged at the inner end of the permanent magnet 4, and the oil slinger 9 is fixed on the shaft sleeve 2 and rotates along with the shaft sleeve; a gap between the oil slinger 9 and the permanent magnet 4 is filled with magnetic lubricating grease 10; in order to increase the sealing performance of the structure, the end surface of the oil slinger 9 and the shaft hub 1 form labyrinth type seal; in order to prevent impurities from entering the sealing structure, a packing box 11 is arranged at the contact axial gap between the shaft hub 1 and the shaft sleeve.

Example four

As shown in fig. 5, a contra-rotating seal assembly comprises a hub 1 and a sleeve 2, which are respectively used for connecting a pair of components rotating in opposite directions; the shaft hub 1 is wrapped on the shaft sleeve 2 and is connected with the shaft sleeve 2 through a bearing 3; both sides of the bearing 3 are provided with a salient pole 5 and a concave pole 6, the concave pole 6 is provided with a U-shaped groove and is connected with the permanent magnet 4 into a whole to be fixed on the shaft hub 1; the permanent magnet 4 is of an annular structure, is magnetized by radiation and is a monopole radiation ring, and the concave pole 6 is formed by injection molding of a flexible material; an adjusting gasket 12 is arranged between the inner permanent magnet 4 and the bearing 3; the salient pole 5 is fixed on the shaft sleeve 2, the top of the salient pole is arranged in the groove, and a U-shaped gap is formed between the salient pole and the groove; the gap is filled with magnetic fluid 7; the magnetic fluid 7 is accumulated at the bottom of the groove under the action of a radial magnetic field provided by the permanent magnet 4 right above the outer side of the concave pole 6, and a U-shaped sealing belt is formed between the salient pole 5 and the concave pole 6 by utilizing the principle of static pressure balance of fluid in a U-shaped pipe; in the running state, the magnetic fluid 7 is driven by the concave electrode 6 to rotate, so that the magnetic fluid 7 generates a radial outward centrifugal force; the magnetic fluid 7 is accumulated at the U-shaped bottom of the concave electrode 6 under the combined action of centrifugal force and magnetic force; in order to increase the capacity of the concave electrode 6 for driving the magnetic fluid 7 to rotate, the carrier liquid strip 8 is bonded on the inner surface of a U-shaped groove of the concave electrode 6; an oil slinger 9 is arranged at the inner end of the permanent magnet 4, and the oil slinger 9 is fixed on the shaft sleeve 2 and rotates along with the shaft sleeve; a gap between the oil slinger 9 and the permanent magnet 4 is filled with magnetic lubricating grease 10; in order to increase the sealing performance of the structure, the end surface of the oil slinger 9 and the shaft hub 1 form labyrinth type seal; in order to prevent impurities from entering the sealing structure, a packing box 11 is arranged at the contact axial gap between the shaft hub 1 and the shaft sleeve.

It should be pointed out that, two magnetic fluid sealing strips of this contra-rotating seal assembly wrap up the bearing in it, a confined space has been formed, if the both sides clearance of this contra-rotating seal assembly is under equal pressure, two magnetic fluid sealing strips receive external pressure simultaneously and inwards squint, lead to the enclosure space gas to be compressed, atmospheric pressure increases, only under the static seal state, the atmospheric pressure of inside increase, just can play fine sealed effect adding magnetic force, prevent that liquid from getting into inside the bearing, fine assurance can not receive the resistance of liquid when the bearing moves, reduce power loss, this kind of contra-rotating seal assembly is used in the motor propeller, can allow outside fluid freely to get into inside the motor, with the inner space together, cool off motor stator and rotor, do not influence the performance of bearing.

EXAMPLE five

As shown in fig. 6, a contra-rotating seal assembly comprises a hub 1 and a sleeve 2, which are respectively used for connecting a pair of components rotating in opposite directions; the shaft hub 1 is wrapped on the shaft sleeve 2 and is connected with the shaft sleeve 2 through a bearing 3; both sides of the bearing 3 are provided with a salient pole 5 and a concave pole 6, the concave pole 6 is provided with a U-shaped groove and is connected with the permanent magnet 4 into a whole and fixed on the shaft sleeve 2 through a rotating ring 25; the permanent magnet 4 is of an annular structure, is magnetized by radiation and is a monopole radiation ring, and the concave pole 6 is formed by injection molding of a flexible material; a spacer ring 13 is arranged between the permanent magnet 4 at the inner side end and the bearing 3; the salient pole 5 is fixed on the shaft hub 1, the top of the salient pole is arranged in the groove, and a U-shaped gap is formed between the salient pole and the groove; the gap is filled with magnetic fluid 7; the magnetic fluid 7 is accumulated at the bottom of the groove under the action of a radial magnetic field provided by the permanent magnet 4 right above the outer side of the concave pole 6, and a U-shaped sealing belt is formed between the salient pole 5 and the concave pole 6 by utilizing the principle of static pressure balance of fluid in a U-shaped pipe; in the running state, the magnetic fluid 7 is driven by the concave electrode 6 to rotate, so that the magnetic fluid 7 generates a radial outward centrifugal force; the magnetic fluid 7 is accumulated at the U-shaped bottom of the concave electrode 6 under the combined action of centrifugal force and magnetic force; in order to increase the capacity of the concave electrode 6 for driving the magnetic fluid 7 to rotate, the carrier liquid strip 8 is bonded on the inner surface of a U-shaped groove of the concave electrode 6; the upper end of the outer ring of the rotating ring 25 is provided with an auxiliary permanent magnet 41 which is fixedly arranged on the shaft hub 1 and forms a gap with the rotating ring 25; the gap between the rotating ring 25 and the auxiliary permanent magnet 41 is filled with magnetic grease 10; in order to prevent impurities from entering the sealing structure, a packing box 11 is arranged at the contact axial gap between the shaft hub 1 and the shaft sleeve.

It should be noted that, at this time, the inner side of the concave pole 6 and the outer side of the rotating ring 25 both form a "U" shaped sealing belt, when the rotating ring 25 drives the concave pole 6 to rotate, the inner and outer sealing belts resist external pressure difference under the same direction superposition of centrifugal force and magnetic force, and the sealing performance is doubly ensured; the magnetic grease 10 can be replaced by the magnetic fluid 7, if the cost is not counted.

EXAMPLE six

As shown in fig. 7, a contra-rotating propeller includes a housing 26, a front duct 19 and a rear duct 20; the front guide pipe 19 and the rear guide pipe 20 are both in a cylindrical ring structure and are butted together through the contra-rotating sealing assembly in the embodiment, wherein the front guide pipe 19 is butted in the shaft hub 1, the rear guide pipe 20 is butted in the shaft sleeve 2, and in order to ensure the installation precision, the shaft hub 1 and the shaft sleeve 2 are both provided with seam allowance structures; the front duct 19 and the rear duct 20 are connected together by a contra-rotating seal assembly and then fixed in a front end cover 23 and a rear end cover 24 on both sides of a housing 26 by seal bearing assemblies which can be sealed in the same sealing way as the contra-rotating seal assembly; to increase the structural strength of the interface between the forward conduit 19 and the aft conduit 20, a support bearing may be interposed between the counter-rotating seal assembly and the housing 26; a right driving device is arranged in the space between the front guide pipe 19 and the shell and between the rear guide pipe 20 and the shell, and the driving device is a combination of a motor rotor and a motor stator; a front propeller 21 is arranged on the inner side of the front guide pipe 19, and a front motor rotor 17 is arranged on the outer side; the inner side of the rear duct 20 is provided with a rear propeller 22, and the outer side is provided with a rear motor rotor 18; the blades of the front propeller 21 and the rear propeller 22 are opposite; the front motor rotor 17 and the rear motor rotor 8 realize contra-rotating movement in opposite directions under the action of rotating magnetic fields provided by the front motor stator 15 and the rear motor stator 6, and in an operating state, the magnetic fluid 7 is driven by the concave pole 6 to rotate, so that the magnetic fluid 7 generates radial outward centrifugal force; the magnetic fluid 7 is accumulated at the bottom of the concave electrode 6 under the combined action of centrifugal force and magnetic force to realize sealing, the larger the rotating speed is, the larger the centrifugal force is, the better the sealing effect is, and the self-adjusting capacity is strong.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A counter-rotating seal assembly characterized by: comprises a shaft hub and a shaft sleeve which are respectively used for connecting a pair of components which rotate in opposite directions; the shaft hub is wrapped on the shaft sleeve and is connected with the shaft sleeve through a bearing; the side edge of the bearing is provided with a salient pole and a concave pole; the concave pole is fixed on the shaft sleeve or the shaft hub, the outer side of the concave pole is provided with a permanent magnet, and the inner side of the concave pole is provided with a U-shaped or V-shaped groove; the salient pole is fixed on the shaft hub or the shaft sleeve, the top of the salient pole is arranged in the groove, and a U-shaped or V-shaped gap is formed between the salient pole and the groove; the gap is filled with magnetic fluid; the magnetic fluid is accumulated at the bottom of the groove under the action of a magnetic field provided by the inner magnetic pole of the concave pole permanent magnet, and a U-shaped or V-shaped sealing strip is formed between the salient pole and the concave pole by utilizing the principle of static pressure balance of fluid in the U-shaped pipe.

2. A counter-rotating seal assembly according to claim 1, wherein: and a carrier liquid strip for increasing the contact area with the magnetic fluid is arranged in the gap and is bonded on the concave electrode.

3. A counter-rotating seal assembly according to claim 1, wherein: the permanent magnet is in an annular structure, adopts radiation magnetization and is a monopole radiation ring.

4. A counter-rotating seal assembly according to claim 1, wherein: the permanent magnet and the concave pole are connected into a whole and fixedly installed on the shaft sleeve through the rotating ring, and the salient pole is fixedly installed on the shaft sleeve.

5. A counter-rotating seal assembly according to claim 1, wherein: the permanent magnet and the concave pole are connected into a whole and fixedly mounted on the shaft hub, and the salient pole is fixedly mounted on the shaft sleeve.

6. A counter-rotating seal assembly according to claim 5, wherein: the salient pole side is equipped with the oil slinger, the oil slinger is fixed on the axle sleeve, is equipped with labyrinth type seal structure between the axle sleeve and the axle hub.

7. A counter-rotating seal assembly according to claim 6, wherein: the oil slinger side end is provided with an isolating ring and a mud slinger sequentially from inside to outside, the isolating ring is fixed on the shaft hub, and the mud slinger is fixed on the shaft sleeve.

8. A counter-rotating seal assembly according to claim 3, wherein: the edge of the concave pole is in contact with the salient pole to form a closed space, and the magnetic fluid is limited in the closed space of a U shape or a V shape formed between the salient pole and the concave pole.

9. A contra-rotating propeller characterized by: comprises a shell, a front conduit and a rear conduit; the front guide pipe and the rear guide pipe are movably butted through the contra-rotating sealing assembly of any one of claims 1 to 8, and the front guide pipe and the rear guide pipe which are connected into a whole are fixed in end covers at two sides of the shell through bearing assemblies; propellers are fixedly arranged in the inner rings of the front guide pipe and the rear guide pipe; and driving devices are arranged in spaces between the front guide pipe and the shell and between the rear guide pipe and the shell, and the driving devices provide power for realizing the mutual reverse rotation of the front guide pipe and the rear guide pipe.