WO2020150967A1

WO2020150967A1 - Magnetic liquid sealing device having function of preventing non-magnetic substance pollution

Info

Publication number: WO2020150967A1
Application number: PCT/CN2019/072999
Authority: WO
Inventors: 李德才; 刘霄; 陈思宇; 李倩; 孙睿; 杨纪显; 李钲皓
Original assignee: 清华大学
Priority date: 2019-01-24
Filing date: 2019-01-24
Publication date: 2020-07-30

Abstract

A magnetic liquid sealing device (100) having a function of preventing non-magnetic substance pollution. The magnetic liquid sealing device comprises a shaft housing (1), a rotating shaft (2), a shaft sleeve (3), two bearings (4), a first pole shoe (5), a second pole shoe (6), and a permanent magnet (7). A magnetic liquid (13) for sealing is adsorbed between the top surfaces of first pole teeth (501) of the first pole shoe and the outer circumferential surface of the shaft sleeve. Second pole teeth (601) of the second pole shoe comprise a plurality of flat teeth (6011) and at least one oblique tooth (6012). The top surface of the oblique tooth is formed, in a direction toward the outer end, into an oblique surface extending in a direction away from the rotating shaft. The permanent magnet is sleeved on the shaft sleeve. The magnetic liquid sealing device has a better function of preventing non-magnetic substance pollution.

Description

Magnetic liquid sealing device with function of preventing non-magnetic substance pollution

Technical field

The invention belongs to mechanical engineering sealing technology, and is particularly suitable for magnetic liquid sealing in an environment with more non-magnetic materials such as dust.

Background technique

The magnetic fluid sealing technology is gradually being used by more and more industries due to its advantages of zero leakage, no mechanical wear, long life and simple structure. However, during use, it is inevitable that non-magnetic materials such as dust will enter the magnetic liquid sealing device, which will affect the magnetic liquid sealing effect and service life. The prior art discloses a magnetic liquid sealing device with self-cleaning function. The device puts the right pole shoe on the left side of the right bearing. The impurities entering on the right side will enter the right bearing first, and the right bearing is contaminated. Changing the shape of the pole piece cannot prevent impurities from entering the magnetic liquid, and does not serve the purpose of preventing contamination of the magnetic liquid sealing device.

The technical problem to be solved by the present invention is that in the existing magnetic liquid sealing device, especially the sealing device used in an environment with a lot of non-magnetic materials such as dust, it is inevitable that non-magnetic materials enter the magnetic liquid sealing device and cause the sealing device Contamination, resulting in a decrease in sealing effect and service life.

Summary of the invention

The present invention aims to solve at least one of the technical problems existing in the prior art. For this reason, the present invention proposes a magnetic liquid sealing device with a function of preventing non-magnetic material contamination, and the magnetic liquid sealing device has a better function of preventing non-magnetic material contamination.

According to an embodiment of the present invention, a magnetic liquid sealing device with a function of preventing contamination by non-magnetic substances includes: a shaft housing in which a shaft chamber is provided, and two ends of the shaft chamber are inner and outer ends respectively; a rotating shaft, A shaft is rotatably arranged in the shaft chamber, and the shaft extends from the outer end of the shaft chamber to the inner end of the shaft chamber; a shaft sleeve, the shaft sleeve is sleeved on the shaft; two Bearing, the two bearings are respectively sleeved on the shaft sleeve and arranged adjacent to the inner end of the shaft chamber; a first pole shoe, the first pole shoe is sleeved on the shaft sleeve, the first The pole shoes are located on the side facing the outer ends of the two bearings, the inner peripheral wall of the first pole shoes is provided with a plurality of first pole teeth, and the tooth top surface of each first pole tooth is connected to the shaft A magnetic liquid for sealing is adsorbed between the outer circumferential surface of the sleeve; a second pole shoe, the second pole shoe is sheathed on the shaft sleeve, and the second pole shoe is located at the outer end of the first pole shoe On one side, the inner peripheral wall of the second pole shoe is provided with a plurality of second pole teeth, and at least part of the tooth top surface of the second pole tooth and the outer peripheral surface of the sleeve are attracted by magnetic seals for sealing. Liquid, the plurality of second pole teeth include a plurality of flat teeth and at least one oblique tooth, the oblique tooth is located on a side of the flat tooth facing the outer end, and the tooth top surface of the oblique tooth is in a direction toward the outer end The upper part is formed as a slope extending in a direction away from the shaft sleeve; a permanent magnet, the permanent magnet is sleeved on the shaft sleeve and is located between the first pole piece and the second pole piece.

According to the magnetic liquid sealing device with the function of preventing non-magnetic substance contamination, since the first pole piece and the second pole piece are located at the outer ends of the two bearings, it is better to prevent non-magnetic substances from entering the two bearings. Contaminated bearings occurred in each bearing. At the same time, the second pole tooth at the outer end of the second pole piece is formed as a helical tooth, and the tooth top surface of the helical tooth is formed as a slope extending away from the shaft sleeve in the direction toward the outer end, which increases the permanent magnet The magnetic field intensity gradient generated in the magnetic liquid enhances the function of the magnetic sealing device to prevent contamination by non-magnetic substances.

In some embodiments, the included angle between the tooth top surface of the helical tooth and the axis of the sleeve is a, and a satisfies the relationship: 5°≤a≤9°.

In some embodiments, a magnetic liquid is adsorbed between the tooth top surface of each of the flat teeth and the outer peripheral surface of the sleeve, and the helical teeth are multiple, located at the innermost end of the second pole piece Magnetic liquid is adsorbed between the tooth top surface of the helical tooth and the outer circumferential surface of the sleeve, and the rest is located between the tooth top surface of the helical tooth of the second pole piece and the outer circumferential surface of the sleeve without magnetism liquid.

In some embodiments, the magnetic liquid sealing device with the function of preventing non-magnetic material contamination further includes: two sealing rings, one of which is located between the first pole piece and the shaft housing , The other sealing ring is located between the second pole piece and the shaft housing.

In some embodiments, the magnetic fluid sealing device with the function of preventing non-magnetic substance contamination further includes two first adjusting washers, one of the first adjusting washers is located between the two bearings, and the other The first adjusting washer is located between the first pole piece and the bearing adjacent to it.

In some embodiments, the inner end of the shaft housing is formed with a first protrusion, a second adjusting washer is provided between one of the bearings and the first protrusion, and the outer end of the shaft housing is connected with A flange, the flange having a second protrusion extending into the shaft chamber.

In some specific embodiments, the magnetic liquid sealing device with the function of preventing non-magnetic material contamination further includes a third adjusting washer, and the third adjusting washer is located between the second protrusion and the second pole. Between the boots.

In some embodiments, the permanent magnet is made of one of neodymium iron boron, samarium cobalt, and iron cobalt nickel.

In some embodiments, the gap between the tooth top surface of the first pole tooth and the outer circumferential surface of the sleeve is b1, and the value range of b1 is 0.1mm-0.2mm. The gap between the tooth top surface and the outer circumferential surface of the sleeve is b2, and the value range of b2 is 0.1mm-0.2mm.

In some specific embodiments, the width of the first pole tooth ranges from 3 to 5 times b1, the height of the first pole tooth ranges from 20 to 30 times b1; the width of the second pole tooth The range is 3 to 5 times of b2, and the height of the second pole tooth ranges from 20 to 30 times of b2.

The additional aspects and advantages of the present invention will be partly given in the following description, and part of them will become obvious from the following description, or be understood through the practice of the present invention.

Description of the drawings

The above and/or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, in which:

Fig. 1 is a schematic diagram of the overall structure of a magnetic liquid sealing device according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of the structure of the fitting place between the first pole piece and the rotating shaft in the embodiment of the present invention.

Fig. 3 is a schematic diagram of the structure of the fitting position between the second pole piece and the rotating shaft in the embodiment of the present invention.

Fig. 4 is a schematic structural diagram of a fitting position between a second pole piece and a rotating shaft according to another embodiment of the present invention.

Reference signs:

Magnetic liquid sealing device 100,

Axle housing 1, shaft chamber 101, first protrusion 102, bolt hole 103,

Shaft 2,

Shaft sleeve 3.

Bearing 4.

The first pole shoe 5, the first pole tooth 501,

Second pole shoe 6, second pole tooth 601, flat tooth 6011, helical tooth 6012,

Permanent magnet 7,

Seal ring 8,

The first adjusting washer 9,

The second adjusting washer 10,

The third adjustment washer 11,

Flange 12, second protrusion 1201,

Magnetic fluid 13.

detailed description

The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the drawings are exemplary, and are only used to explain the present invention, but should not be construed as limiting the present invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axial", The orientation or positional relationship indicated by "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the pointed device or element It must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention. In addition, the features defined with "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

In the description of the present invention, it should be noted that the terms "installation", "connection" and "connection" should be understood in a broad sense unless otherwise clearly specified and limited. For example, they can be fixed or detachable. Connected or integrally connected; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication between two components. For those of ordinary skill in the art, the specific meaning of the above-mentioned terms in the present invention can be understood in specific situations.

The specific structure of the magnetic liquid sealing device 100 with the function of preventing non-magnetic substance contamination according to an embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the magnetic liquid sealing device 100 with the function of preventing non-magnetic substance contamination according to the embodiment includes: a shaft housing 1, a rotating shaft 2, a shaft sleeve 3, two bearings 4, a first pole shoe 5, a second pole Shoe 6 and permanent magnet 7.

Specifically, a shaft chamber 101 is provided in the shaft housing 1, and two ends of the shaft chamber 101 are an inner end and an outer end, respectively. The rotating shaft 2 is rotatably arranged in the shaft chamber 101, and the rotating shaft 2 extends from the outer end of the shaft chamber 101 to the inner end of the shaft chamber 101. Two bearings 4 are respectively sleeved on the shaft sleeve 3 and arranged adjacent to the inner end of the shaft chamber 101. The first pole shoe 5 is sheathed on the shaft sleeve 3. The first pole shoe 5 is located on the side of the two bearings 4 facing the outer end. The inner peripheral wall of the first pole shoe 5 is provided with a plurality of first pole teeth 501, each A magnetic fluid 13 for sealing is adsorbed between the tooth top surface of the first pole tooth 501 and the outer peripheral surface of the sleeve 3 (as shown in FIG. 2, f in FIG. 2 represents the outer peripheral surface of the sleeve 3). The second pole shoe 6 is sheathed on the sleeve 3, the second pole shoe 6 is located on the side of the first pole shoe 5 facing the outer end, and the inner peripheral wall of the second pole shoe 6 is provided with a plurality of second pole teeth 601, at least A magnetic fluid 13 for sealing is adsorbed between the tooth top surface of part of the second pole tooth 601 and the outer peripheral surface of the sleeve 3 (as shown in Figs. 3 to 4, f in Figs. 3 and 4 represents the sleeve 3 The plurality of second pole teeth 601 include a plurality of flat teeth 6011 and at least one helical tooth 6012. The helical tooth 6012 is located on the side of the flat tooth 6011 facing the outer end, and the tooth top surface of the helical tooth 6012 is facing the outer end. The direction is formed as a slope extending away from the shaft sleeve 3, and the permanent magnet 7 is sleeved on the shaft sleeve 3 and is located between the first pole shoe 5 and the second pole shoe 6.

It can be understood that, since the first pole shoe 5 and the second pole shoe 6 are both located on the side facing the outer ends of the two bearings 4, the magnetic fluid 13 and the second pole tooth between the first pole tooth 501 and the sleeve 3 The magnetic liquid 13 between the 601 and the shaft sleeve 3 has a better sealing effect, so as to better avoid the phenomenon of non-magnetic substances entering the two bearings 4 and contaminating the bearings 4.

It should be noted that since the second pole tooth 601 includes at least one helical tooth 6012 located at the outer end, and the tooth top surface of the helical tooth 6012 is formed in the direction toward the outer end as an inclined surface extending away from the sleeve 3, the first The shape of the two-pole teeth 601 changes, so that the permanent magnet 7 generates a magnetic field intensity gradient in the magnetic liquid 13, and the magnetic liquid 13 exerts a magnetic buoyancy force toward the outer end of the non-magnetic substance. In this way, the entire sealing device will generate an outward force to the non-magnetic material entering from the outside, achieving the purpose of preventing non-magnetic material pollution, improving the sealing effect, increasing the service life of the bearing 4, and being more suitable for magnetic liquids in harsh environments 13 seal.

According to the magnetic liquid sealing device 100 with the function of preventing non-magnetic substance contamination, since the first pole shoe 5 and the second pole shoe 6 are located at the outer ends of the two bearings 4, non-magnetic materials are better avoided. Substances enter the two bearings 4 and contaminate the bearings 4. At the same time, the second pole tooth 601 at the outer end of the second pole shoe 6 is formed as a helical tooth 6012, and the tooth top surface of the helical tooth 6012 is formed as an inclined surface extending in a direction away from the sleeve 3 in the direction toward the outer end, The magnetic field intensity gradient generated by the permanent magnet 7 in the magnetic liquid 13 is increased, and the function of the magnetic sealing device to prevent contamination by non-magnetic substances is enhanced.

It should be additionally noted that the type of the magnetic liquid 13 in the embodiment of the present invention can be selected according to the difference of the sealing gas and the temperature environment, and the magnetic liquid 13 of different base liquids can be selected and injected into the first pole piece 5 and the second pole piece 5 and the second pole piece at a time during assembly. In the gap between the pole piece 6 and the shaft sleeve 3. Choose kerosene or hydrocarbon or diester-based carrier fluid in a vacuum-sealed environment, and fluorocarbon-based carrier fluid in an acid- and alkali-resistant sealed environment. Use high-quality kerosene or silicate lipid or dilipid-based carrier fluid in a low-temperature sealed environment. Therefore, the magnetic liquid sealing device 100 according to the embodiment of the present invention can select the type of magnetic liquid according to actual conditions, thereby expanding the practical range of the magnetic liquid sealing device 100.

In addition, the material of the first pole shoe 5 and the second pole shoe 6 in the embodiment of the present invention can be made of electrical pure iron. Of course, in other embodiments of the present invention, the first pole shoe 5 and the second pole shoe 6 The material can be selected according to the actual situation and is not limited to electrical pure iron. At the same time, the number of poles of the first pole tooth 501 and the second pole tooth 601 is determined according to the pressure difference condition of the seal, and the sealing capacity of each stage is 0.5 atmosphere.

In some embodiments, the angle between the tooth top surface of the helical tooth 6012 and the axis of the sleeve 3 is a, and a satisfies the relationship: 5°≤a≤9°. It is understandable that, according to the experimental results, when the angle between the tooth top surface of the helical tooth 6012 and the axis of the sleeve 3 is between 5°-9°, it is more conducive to increase the permanent magnet 7 in the magnetic liquid 13 The intensity gradient of the magnetic field generated in the magnetic field, thereby better enhancing the sealing effect of the magnetic liquid sealing device 100. Of course, in other embodiments of the present invention, the angle between the tooth top surface of the helical tooth 6012 and the axis of the sleeve 3 can also be selected according to actual needs and is not limited to the above range.

In some embodiments, as shown in FIG. 4, the magnetic fluid 13 is adsorbed between the tooth top surface of each flat tooth 6011 and the outer peripheral surface of the sleeve 3, and there are multiple helical teeth 6012 located in the second pole piece 6. Magnetic fluid 13 is adsorbed between the tooth top surface of the innermost helical tooth 6012 and the outer circumferential surface of the sleeve 3, and the rest is located between the tooth top surface of the helical tooth 6012 of the second pole piece 6 and the outer circumferential surface of the sleeve 3 Does not absorb magnetic liquid. It should be noted that the magnetic liquid 13 is not adsorbed between the tooth top surface of the remaining helical teeth 6012 of the second pole piece 6 and the outer peripheral surface of the sleeve 3 means that the tooth top surface of the remaining helical teeth 6012 is The gap between the outer peripheral surfaces is filled with air. That is to say, during the use of the magnetic liquid sealing device 100, there is an air gap between the tooth top surfaces of the remaining helical teeth 6012 and the shaft sleeve 3.

In some embodiments, as shown in FIG. 1, the magnetic liquid sealing device 100 with the function of preventing non-magnetic substance contamination further includes two sealing rings 8, one of which is located between the first pole piece 5 and the shaft housing 1. , The other sealing ring 8 is located between the second pole piece 6 and the shaft housing 1. It can be understood that there is a sealing ring 8 between the first pole shoe 5 and the shaft housing 1 and the second pole shoe 6 and the shaft housing 1 to ensure that the first pole shoe 5, the second pole shoe 6 and the shaft housing 1 The sealing prevents non-magnetic materials from entering the inner end of the shaft chamber 101 from the gap between the first pole piece 5 and the shaft housing 1 or the gap between the second pole piece 6 and the shaft housing 1. In other words, the sealing ring 8 provided between the first pole shoe 5 and the shaft housing 1 and the second pole shoe 6 and the shaft housing 1 can better ensure the sealing effect of the magnetic sealing device.

It should be supplemented that the sealing ring 8 can be formed as an O-ring. Of course, the function of the sealing ring 8 is to ensure the sealing between the first pole shoe 5 and the shaft housing 1 and the second pole shoe 6 and the shaft housing 1. The material, shape and sealing grade of the sealing ring 8 can be selected according to actual needs and is not limited to O-rings.

Advantageously, the outer peripheral surfaces of the first pole shoe 5 and the second pole shoe 6 are respectively provided with sealing grooves for fitting with the sealing ring 8. Thus, the axial movement of the sealing ring 8 is avoided, and the sealing effect between the first pole shoe 5 and the shaft housing 1 and the second pole shoe 6 and the shaft housing 1 is further ensured.

In some embodiments, as shown in FIG. 1, the magnetic fluid sealing device 100 with the function of preventing non-magnetic substance contamination further includes two first adjusting washers 9, one of which is located between the two bearings 4, Another first adjusting washer 9 is located between the first pole shoe 5 and the bearing 4 adjacent to it.

It can be understood that the first adjusting washer 9 located between the two bearings 4 is mainly used to adjust the position between the two bearings 4 to ensure that the sleeve 3 can rotate stably under the support of the two bearings 4. The main function of the first adjusting washer 9 located between the bearing 4 and the first pole piece 5 is to prevent the magnetic liquid 13 from being adsorbed between the bearing 4 and the sleeve 3. Specifically, the first pole piece 5 is in contact with the permanent magnet 7, and the bearing 4 is generally made of a magnetic metal material. In order to prevent the bearing 4 from being magnetized by the first pole piece 5, it should be attracted to the first pole piece 5 and When the phenomenon that the magnetic liquid 13 between the shaft sleeve 3 adsorbs between the bearing 4 and the shaft sleeve 3 occurs, it is necessary to provide a first adjusting washer 9 between the bearing 4 and the first pole piece 5. Therefore, the first adjusting washer 9 between the bearing 4 and the first pole piece 5 better guarantees the sealing effect of the magnetic liquid sealing device 100. It should be supplemented that the first adjusting gasket 9 may be a rubber sealing gasket. Of course, the shape, material and size of the first adjusting gasket 9 can be selected according to actual needs and is not limited to the rubber sealing ring 8.

In some embodiments, as shown in FIG. 1, the inner end of the shaft housing 1 is formed with a first protrusion 102, and a second adjusting washer 10 is provided between one of the bearings 4 and the first protrusion 102, and the shaft housing 1 A flange 12 is connected to the outer end, and the flange 12 has a second protrusion 1201 extending into the shaft chamber 101. Therefore, the two bearings 4, the first pole piece 5, the second pole piece 6 and the permanent magnet 7 can be better restricted between the first protrusion 102 and the second protrusion 1201, avoiding the two bearings 4 1. The first pole piece 5, the second pole piece 6 and the permanent magnet 7 move axially, which affects the sealing effect of the magnet liquid sealing device. The second adjusting washer 10 can be a rubber sealing ring. Of course, the main function of the second adjusting washer 10 is to avoid axial movement of the two bearings 4, the first pole shoe 5, the second pole shoe 6 and the permanent magnet 7. Another aspect is to avoid excessive friction between the bearing 4 and the first protrusion 1201. Therefore, the third adjustment gasket 11 can be selected according to actual needs, and is not limited to a rubber sealing ring.

In some specific embodiments, as shown in FIG. 1, the magnetic liquid sealing device 100 with the function of preventing non-magnetic substance contamination further includes a third adjustment washer 11, which is located between the second protrusion 1201 and the second pole. Between 6 boots. As a result, the axial movement of the two bearings 4, the first pole shoe 5, the second pole shoe 6 and the permanent magnet 7 can be further avoided. The third adjusting washer 11 can be a rubber sealing ring. Of course, the main function of the third adjusting washer 11 is to prevent the two bearings 4, the first pole piece 5, the second pole piece 6 and the permanent magnet 7 from axial movement, so The third adjustment gasket 11 can be selected according to actual needs, and is not limited to a rubber sealing ring.

In some embodiments, the permanent magnet 7 is made of one of neodymium iron boron, samarium cobalt, and iron cobalt nickel. It can be understood that the permanent magnet 7 is made of neodymium iron boron under the normal temperature and sealed condition, the permanent magnet 7 is samarium cobalt when the temperature is below 300°C, and the permanent magnet 7 is iron, cobalt and nickel when the temperature is 400°C. Therefore, different permanent magnets 7 are selected under different sealing temperature conditions, which improves the practical range of the magnetic liquid sealing device 100 of the embodiment of the present invention. In addition, it should be noted that changing the permanent magnets 7 with different magnetic field strengths can change the magnetic buoyancy of the magnetic liquid 13 on non-magnetic substances. Therefore, even if the permanent magnets 7 use the same material, the permanent magnets 7 with different magnetic field strengths can be selected to better achieve the function of preventing non-magnetic material pollution.

In some embodiments, the gap between the tooth top surface of the first pole tooth 501 and the outer circumferential surface of the sleeve 3 is b1, and the value range of b1 is 0.1mm-0.2mm, and the tooth top surface of the second pole tooth 601 The gap with the outer peripheral surface of the sleeve 3 is b2, and the value range of b2 is 0.1mm-0.2mm. Experimental verification shows that when b1 and b2 are controlled within the range of 0.1 mm-0.2 mm, the magnetic liquid sealing device 100 can have a better sealing effect. Of course, in other embodiments of the present invention, the specific value ranges of b1 and b2 can be limited according to actual needs.

In some specific embodiments, the width of the first pole tooth 501 ranges from 3 to 5 times b1, and the height of the first pole tooth 501 ranges from 20 to 30 times b1. The width of the second pole tooth 601 ranges from 3 to 5 times that of b2, and the height of the second pole tooth 601 ranges from 20 to 30 times of b2. It should be noted that the width and height of the first pole tooth 501 and the height and width of the second pole tooth 601 affect the magnetic properties between the tooth top surface of the first pole tooth 501 and the outer circumferential surface of the sleeve 3 to a certain extent. The thickness of the liquid 13 and the thickness of the magnetic liquid 13 between the tooth top surface of the second pole tooth 601 and the outer peripheral surface of the sleeve 3. That is to say, the width and height of the first pole tooth 501 and the height and width of the second pole tooth 601 will affect the sealing effect of the entire magnetic sealing device. It has been verified by experiments that when the height and width of the first pole tooth 501 and the second pole tooth When the height and width of the teeth 601 meet the above-mentioned value range, the magnetic liquid sealing device 100 has a better sealing effect. Of course, what needs to be added here is that in the specific embodiment of the present invention, the width and height of the first pole tooth 501 and the height and width of the second pole tooth 601 can be adjusted according to actual needs and are not limited to the above values. range. In addition, it should be noted here that although the range of the height and width of the first pole tooth 501 and the second pole tooth 601 is the same, in actual practice, the first pole tooth 501 and the second pole tooth 601 The height and width can be the same or different. The height of the flat tooth 6011 and the helical tooth 6012 of the second pole tooth 601 may be the same or different.

Examples:

Hereinafter, referring to FIG. 1, a magnetic liquid sealing device 100 with a function of preventing non-magnetic substance contamination according to a specific embodiment of the present invention will be described.

The magnetic liquid sealing device 100 with the function of preventing contamination by non-magnetic substances of this embodiment can be used in a positive pressure sealing environment with little radial runout.

The magnetic liquid sealing device 100 with the function of preventing non-magnetic substance contamination of this embodiment includes a shaft housing 1, a rotating shaft 2, a shaft sleeve 3, two bearings 4, a first pole shoe 5, a second pole shoe 6, a permanent magnet 7, Two sealing rings 8, two first adjusting gaskets 9 and a third adjusting gasket 11. A shaft chamber 101 is provided in the shaft housing 1, and two ends of the shaft chamber 101 are an inner end and an outer end, respectively. The inner end of the shaft housing 1 is formed with a first protrusion 102, a second adjusting washer 10 is provided between one of the bearings 4 and the first protrusion 102, and the flange 12 is connected to the outside of the shaft housing 1 and the shaft sleeve 3 by screws. At the end, the flange 12 has a second protrusion 1201 extending into the shaft chamber 101. The inner end surface of the shaft housing 1 is provided with a plurality of bolt holes 103 distributed around its axis. The rotating shaft 2 is rotatably arranged in the shaft chamber 101, and the rotating shaft 2 extends from the outer end of the shaft chamber 101 to the inner end of the shaft chamber 101. Two bearings 4 are respectively sleeved on the shaft sleeve 3 and arranged adjacent to the inner end of the shaft chamber 101. The first pole shoe 5 is sheathed on the shaft sleeve 3, and the first pole shoe 5 is located on the side of the two bearings 4 facing the outer ends. As shown in Figure 2, the inner peripheral wall of the first pole shoe 5 is provided with five first pole teeth 501, and a seal is adsorbed between the tooth top surface of each first pole tooth 501 and the outer peripheral surface of the sleeve 3. Magnetic fluid 13. The second pole shoe 6 is sheathed on the shaft sleeve 3, and the second pole shoe 6 is located on the side of the first pole shoe 5 facing the outer end. As shown in Figure 4, the inner peripheral wall of the second pole shoe 6 is provided with five second pole teeth 601. The second pole teeth 601 include two flat teeth 6011 and three helical teeth 6012. The helical teeth 6012 are located on the flat teeth 6011. On the side facing the outer end, the tooth top surface of the helical tooth 6012 is formed as a slope extending away from the shaft sleeve 3 in the direction toward the outer end. The tooth top surface of the helical tooth 6012 and the axis of the shaft sleeve 3 are clamped The angle is a, and a satisfies the relationship: 5°≤a≤9°. The magnetic fluid 13 is adsorbed between the top surfaces of the two flat teeth 6011 and the helical teeth 6012 adjacent to the flat teeth 6011 and the outer peripheral surface of the sleeve 3, and the two helical teeth 6012 are located at the outer end of the second pole piece 6. The magnetic liquid 13 is not adsorbed between the tooth top surface and the outer peripheral surface of the sleeve 3. The permanent magnet 7 is sleeved on the shaft sleeve 3 and is located between the first pole piece 5 and the second pole piece 6. A sealing ring 8 is provided between the first pole shoe 5 and the shaft housing 1, and another sealing ring 8 is provided between the second pole shoe 6 and the shaft housing 1. A first adjusting washer 9 is provided between the two bearings 4, and another first adjusting washer 9 is provided between the first pole shoe 5 and the bearing 4. A third adjusting washer 11 is provided between the second protrusion 1201 and the second pole shoe 6.

In this embodiment, the gap between the tooth top surface of the first pole tooth 501 and the outer peripheral surface of the sleeve 3 is b1, and the value range of b1 is 0.1mm-0.2mm, and the tooth top surface of the second pole tooth 601 The gap with the outer peripheral surface of the sleeve 3 is b2, and the value range of b2 is 0.1mm-0.2mm. The width of the first pole tooth 501 ranges from 3 to 5 times of b1, and the height of the first pole tooth 501 ranges from 20 to 30 times of b1. The width of the second pole tooth 601 ranges from 3 to 5 times that of b2, and the height of the second pole tooth 601 ranges from 20 to 30 times of b2. The permanent magnet 7 of this embodiment is made of neodymium iron boron under normal temperature sealing conditions. When the temperature is below 300° C., the permanent magnet 7 is selected from samarium cobalt, and when the temperature is 400° C., the permanent magnet 7 is selected from iron, cobalt and nickel. The first pole shoe 5 and the second pole shoe 6 are made of electrical pure iron. The magnetic liquid 13 of this embodiment uses kerosene or hydrocarbon or dilipid-based carrier fluid in a vacuum sealed environment, and uses a fluorocarbon-based carrier fluid in an acid- and alkali-resistant sealed environment. Use high-quality kerosene or silicate lipid or dilipid-based carrier fluid in a low-temperature sealed environment.

The installation steps of the magnetic liquid sealing device 100 with the function of preventing non-magnetic substance contamination of the present embodiment are: the second adjusting washer 10, the bearing 4, the first adjusting washer 9, the bearing 4, the first adjusting washer 9, and the first pole The shoe 5, the permanent magnet 7, and the second pole shoe 6 are installed together to form a sealing assembly. After the magnetic liquid 13 is injected into the inner ring surface of the first pole shoe 5 and the second pole shoe 6, the sealing assembly is placed in the shaft chamber 101 On the first protrusion 102 at the inner end, the third adjusting washer 11 and the flange 12, and finally the rotating shaft 2 sleeved with the sleeve 3 is installed in the direction from the inside to the outside, and the installation of the entire magnetic liquid sealing device 100 has been completed.

The main beneficial effect of the magnetic liquid sealing device 100 with the function of preventing non-magnetic substance contamination of this embodiment is that the angle range between the tooth top surface of the second pole tooth 601 and the axis of the sleeve 3 is between 5°-9° , The shape of the second pole tooth 601 changes, the external magnetic field generates a magnetic field intensity gradient in the magnetic liquid 13, and the magnetic liquid 13 has an effect of magnetic buoyancy to the outer end of the non-magnetic substance. In this way, the entire magnetic sealing device will generate an outward force on the non-magnetic material entering from the outside, achieving the purpose of preventing non-magnetic material pollution, improving the sealing effect, increasing the service life of the bearing 4, and being more suitable for magnetic liquids in harsh environments 13 Seal.

In the description of this specification, descriptions with reference to the terms "one embodiment", "some embodiments", "exemplary embodiments", "examples", "specific examples", or "some examples" etc. mean to incorporate the implementation The specific features, structures, materials or characteristics described in the examples or examples are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above-mentioned terms does not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner.

Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and modifications can be made to these embodiments without departing from the principle and purpose of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

A magnetic liquid sealing device with the function of preventing non-magnetic substance contamination, which is characterized in that it comprises:

A shaft housing, a shaft chamber is provided in the shaft housing, and two ends of the shaft chamber are an inner end and an outer end respectively;

A rotating shaft, the rotating shaft is rotatably arranged in the shaft chamber, and the rotating shaft extends from the outer end of the shaft chamber to the inner end of the shaft chamber;

A shaft sleeve, the shaft sleeve is sleeved on the rotating shaft;

Two bearings, the two bearings are respectively sleeved on the shaft sleeve and arranged adjacent to the inner end of the shaft chamber;

A first pole shoe, the first pole shoe is sheathed on the sleeve, the first pole shoe is located on the side of the two bearings facing the outer ends, and the inner peripheral wall of the first pole shoe is provided with A plurality of first pole teeth, a magnetic liquid for sealing is adsorbed between the tooth top surface of each first pole tooth and the outer peripheral surface of the sleeve;

The second pole shoe is sheathed on the rotating shaft, the second pole shoe is located on the side of the first pole shoe facing the outer end, and the inner peripheral wall of the second pole shoe is provided with A plurality of second pole teeth, at least part of the second pole teeth’s tooth top surface and the outer peripheral surface of the sleeve are attracted by magnetic liquid for sealing, and the plurality of second pole teeth includes a plurality of flat teeth And at least one oblique tooth, the oblique tooth is located on a side of the flat tooth facing the outer end, and the tooth top surface of the oblique tooth is formed in a direction toward the outer end as an inclined surface extending in a direction away from the shaft sleeve;

A permanent magnet, the permanent magnet is sleeved on the rotating shaft and located between the first pole piece and the second pole piece.
The magnetic fluid sealing device with the function of preventing non-magnetic material contamination according to claim 1, wherein the angle between the tooth top surface of the helical tooth and the axis of the sleeve is a, and a satisfies the relationship Formula: 5°≤a≤9°.
The magnetic liquid sealing device with the function of preventing non-magnetic substance contamination according to claim 1, wherein a magnetic liquid is adsorbed between the tooth top surface of each of the flat teeth and the outer peripheral surface of the shaft sleeve, There are a plurality of helical teeth, and magnetic liquid is adsorbed between the tooth top surface of the helical tooth located at the innermost end of the second pole piece and the outer peripheral surface of the sleeve, and the rest are located on all the second pole pieces. No magnetic liquid is adsorbed between the tooth top surface of the helical tooth and the outer peripheral surface of the sleeve.
The magnetic liquid sealing device with the function of preventing non-magnetic substance contamination according to claim 1, further comprising: two sealing rings, one of the sealing rings is located between the first pole piece and the shaft housing In between, the other sealing ring is located between the second pole piece and the shaft housing.
The magnetic liquid sealing device with the function of preventing contamination by non-magnetic substances according to claim 1, further comprising two first adjusting washers, one of the first adjusting washers is located between the two bearings, The other first adjusting washer is located between the first pole piece and the bearing adjacent to it.
The magnetic liquid sealing device with the function of preventing non-magnetic substance contamination according to claim 1, wherein the inner end of the shaft housing is formed with a first protrusion, and one of the bearing and the first protrusion There is a second adjusting washer between them, the outer end of the shaft shell is connected with a flange, and the flange has a second protrusion extending into the shaft chamber.
The magnetic fluid sealing device with the function of preventing non-magnetic material contamination according to claim 6, further comprising a third adjusting washer, and the third adjusting washer is located between the second protrusion and the second pole Between the boots.
The magnetic fluid sealing device with the function of preventing non-magnetic substance contamination according to any one of claims 1-7, wherein the permanent magnet is made of one of neodymium iron boron, samarium cobalt, iron cobalt nickel to make.
The magnetic liquid sealing device with the function of preventing non-magnetic substance contamination according to any one of claims 1-7, wherein the gap between the tooth top surface of the first pole tooth and the outer peripheral surface of the sleeve The gap is b1, the value range of b1 is 0.1mm-0.2mm, the gap between the tooth top surface of the second pole tooth and the outer peripheral surface of the sleeve is b2, and the value range of b2 is 0.1mm- 0.2mm.
The magnetic fluid sealing device with the function of preventing non-magnetic substance contamination according to claim 9, wherein the width of the first pole tooth is 3 to 5 times b1, and the height of the first pole tooth is 20 to 30 times of b1; the width of the second pole tooth is 3 to 5 times that of b2, and the height of the second pole tooth is 20 to 30 times of b2.