CN107893855B - Concave stepped shaft magnetic fluid sealing device - Google Patents
Concave stepped shaft magnetic fluid sealing device Download PDFInfo
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- CN107893855B CN107893855B CN201711326996.5A CN201711326996A CN107893855B CN 107893855 B CN107893855 B CN 107893855B CN 201711326996 A CN201711326996 A CN 201711326996A CN 107893855 B CN107893855 B CN 107893855B
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- pole shoe
- split
- magnetic fluid
- steps
- transition
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J15/00—Sealings
- F16J15/16—Sealings between relatively-moving surfaces
- F16J15/40—Sealings between relatively-moving surfaces by means of fluid
- F16J15/43—Sealings between relatively-moving surfaces by means of fluid kept in sealing position by magnetic force
Abstract
The invention relates to a concave stepped shaft magnetic fluid sealing device which comprises a shell, a sealing component and an end cover; the sealing assembly comprises a shaft, the shaft is rotatably arranged in the shell through a bearing, the shaft comprises a concave step part, the concave step part comprises a plurality of steps which are sequentially arranged along the axial direction, and the outer walls of the adjacent steps are connected through chamfer-shaped transition surfaces; each transition surface is sleeved with a split type pole shoe matched with the transition surface, the split type pole shoe extends to a position corresponding to a corresponding step at the side part of the transition surface towards one side or two sides of the transition surface, gaps are reserved between the inner wall of the split type pole shoe and the corresponding transition surface and step, and pole teeth are arranged on the inner wall of the split type pole shoe; permanent magnets are arranged between the adjacent split pole shoes. The device has strong pressure resistance and convenient production and processing; when the sealing fails, the loss of the magnetic fluid is small, the secondary pressure bearing capacity and the self-repairing capacity are strong, and the pressure bearing capacity and the sealing reliability of the device under the condition of large gaps are effectively increased, so that the safe working range is enlarged.
Description
Technical Field
The invention relates to a concave stepped shaft magnetic fluid sealing device, and belongs to the field of mechanical engineering sealing.
Background
The magnetic fluid seal is to seal gas and liquid by means of the magnetic fluid seal ring formed by the magnetic fluid under the action of a magnetic field, and the magnetic fluid is used for contact seal between the magnetic fluid seal ring and the seal shaft, so that direct friction between the seal shaft and the seal piece is avoided, and additional load is reduced. The rotary shaft sealing device has the incomparable advantages of other sealing modes in the rotary shaft sealing, is valued by domestic and foreign scholars and engineering technicians, and has important significance in the fields of industry, national defense and the like. The magnetic fluid seal has the unique advantages of no leakage, low abrasion and the like compared with the traditional mechanical seal or filler seal, but the pressure resistance of the magnetic fluid seal is not too high, and the number of seal stages of the multi-stage seal is not too large. Therefore, how to reasonably design the magnetic fluid sealing structure parameters, improve the utilization efficiency of the permanent magnet and enhance the sealing pressure resistance is also a significant research content of the current magnetic fluid sealing technology.
One of the methods of improving the sealing pressure resistance of a magnetic fluid in a large gap is to improve the shape of a pole piece by increasing the number of magnetic sources in a magnetic fluid sealing magnetic circuit, as in the sealing device described in comparative document 1 (patent publication No. CN 202332310U) and the sealing device described in comparative document 2 (patent publication No. CN 206600473U). Although the sealing performance of the two sealing devices described in the above documents is greatly improved compared with that of the common magnetic fluid, the sealing performance of the existing sealing structure still has room for further improvement.
The magnetic fluid seal is to firmly fix the magnetic fluid in the sealing gap by utilizing the magnetic force generated by the permanent magnet in the sealing gap to resist the pressure difference at two sides, thereby achieving the sealing effect.
Disclosure of Invention
The invention aims to provide a concave stepped shaft magnetic fluid sealing device, so that the problem of low pressure resistance of the existing single-magnetic-source magnetic fluid sealing device and multi-magnetic-source magnetic fluid sealing device is solved, and meanwhile, stress concentration is reduced, so that the sealing technology is successfully applied to the fields of high speed, heavy load and the like.
In order to solve the technical problems, the technical scheme of the invention is as follows: a concave stepped shaft magnetic fluid sealing device comprises a shell with two open ends, a sealing component and an end cover for pressing the sealing component in the shell; the sealing assembly comprises a shaft, the shaft is rotatably arranged in the shell through a bearing, the shaft comprises at least one concave step part, the concave step part comprises a plurality of steps which are sequentially arranged along the axial direction, and the outer walls of the adjacent steps are connected through chamfer-shaped transition surfaces; each transition surface is sleeved with a split type pole shoe matched with the transition surface, the split type pole shoe extends to a position corresponding to a corresponding step at the side part of the transition surface towards one side or two sides of the transition surface, gaps are reserved between the inner wall of the split type pole shoe and the corresponding transition surface and step, and pole teeth are arranged on the inner wall of the split type pole shoe and/or on a part of a shaft corresponding to the inner wall of the split type pole shoe; permanent magnets are arranged between the adjacent split pole shoes.
Further, the angle between the transition surface and the central axis of the shaft is 5-75 degrees, preferably 20-60 degrees. Correspondingly, the inclination angle of the part, corresponding to the transition surface, of the inner wall of the split pole shoe is the same as that of the corresponding transition surface.
Preferably, the number of transition surfaces is 2-10.
Further, the pole teeth comprise axial pole teeth and/or transition pole teeth, the axial pole teeth are arranged on the steps and/or on the inner walls of the split pole shoes corresponding to the steps, and the transition pole teeth are arranged on the transition surfaces and/or on the inner walls of the split pole shoes corresponding to the transition surfaces.
Preferably, the pole teeth comprise axial pole teeth and transition pole teeth, the axial pole teeth are arranged on the inner walls of the split pole shoes corresponding to the steps, and the transition pole teeth are arranged on the inner walls of the split pole shoes corresponding to the transition surfaces.
Further, the number of the axial pole teeth and the transition pole teeth on the inner wall of the single split pole shoe is 2-10.
As one embodiment of the present invention, the concave step portion includes 1 first step, 2 second steps, and 2 third steps, diameters of the first steps, the second steps, and the third steps are sequentially increased, and the 2 second steps and the 2 third steps are sequentially symmetrically distributed on both sides of the first steps.
Further, the number of the split type pole shoes is 3, and the split type pole shoes are a first split type pole shoe, a second split type pole shoe and a third split type pole shoe which are distributed along the axial direction in sequence respectively, and the second split type pole shoe is sleeved outside the first step and extends to the corresponding transition corresponding positions towards the two sides of the first step; the first split type pole shoe and the third split type pole shoe are respectively arranged at the left side and the right side of the second split type pole shoe, the first split type pole shoe is sleeved outside the second step and the third step at the left side of the first step, and the third split type pole shoe is sleeved outside the second step and the third step at the right side of the first step; the inner walls of the first split pole shoe, the second split pole shoe and the third split pole shoe are respectively matched with the corresponding steps and the transition surface shape.
Further, a first permanent magnet and a second permanent magnet are respectively arranged between the first split type pole shoe and the second split type pole shoe and between the second split type pole shoe and the third split type pole shoe, and the magnetic poles of the adjacent sides of the first permanent magnet and the second permanent magnet are the same.
Further, the gap size is 0.05-5mm.
Further, an annular groove is formed in the outer wall of the split pole shoe, and a sealing ring is arranged in the annular groove.
Further, in the single concave step part, the outer sides of the two pole shoes at the outermost sides are respectively provided with a first magnetism isolating ring and a second magnetism isolating ring.
Further, the number of the bearings is two, namely a first bearing and a second bearing, and the bearings are respectively arranged on two sides of the concave stepped part.
Further, the end cap is detachably fixed to the right end of the housing.
The concave stepped shaft magnetic fluid sealing device can solve the problem of insufficient pressure resistance of the sealing device under the condition of large clearance. The magnetic fluid is injected into a radial sealing gap and a transitional surface sealing gap formed by the pole shoe and the trapezoid shaft, so that the magnetic fluid sealing of the concave stepped shaft is realized. On the basis of stepped magnetic fluid sealing, the invention improves the structure of the shaft by arranging a multi-stage magnetic source and improving the distribution form of pole teeth on the pole shoe, thereby greatly enhancing the sealing pressure resistance of the magnetic fluid; the concave stepped sealing structure with the chamfer can reduce the loss of magnetic fluid when the sealing fails, reduce stress concentration, facilitate production and processing, and simultaneously increase the secondary bearing capacity and the self-repairing capacity of the sealing device; the pressure resistance and the sealing reliability of the magnetic fluid seal under the condition of large gaps are further improved, and the safe working range of the magnetic fluid seal is enlarged.
In conclusion, the magnetic fluid sealing device has strong pressure resistance and is convenient to produce and process; when the sealing fails, the loss of the magnetic fluid is small, the secondary pressure bearing capacity and the self-repairing capacity are strong, and the pressure bearing capacity and the sealing reliability of the device under the condition of large gaps are effectively increased, so that the safe working range is enlarged.
Drawings
FIG. 1 is a schematic cross-sectional view of a magnetic fluid seal according to a first embodiment of the present invention.
Fig. 2 is a cross-sectional view taken along line A-A of fig. 1.
Detailed Description
The invention will be described in detail below with reference to the drawings in connection with embodiments. It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other. For convenience of description, the words "upper", "lower", "left" and "right" are used hereinafter to denote only the directions corresponding to the upper, lower, left, and right directions of the drawings, and do not limit the structure.
As shown in fig. 1, a concave stepped shaft magnetic fluid sealing device comprises a shell 2 with two open ends, a sealing component and an end cover 10 for pressing the sealing component into the shell 2; the sealing assembly comprises a shaft 1, wherein the shaft 1 is rotatably installed in a shell 2 through a bearing, the shaft 1 comprises a concave step part 101, the concave step part 101 comprises 5 steps which are sequentially arranged along the axial direction, and the outer walls of adjacent steps are connected through chamfer-shaped transition surfaces; each transition surface is sleeved with a split type pole shoe matched with the transition surface, the split type pole shoe extends to a position corresponding to a corresponding step at the side part of the transition surface towards one side or two sides of the transition surface, gaps are reserved between the inner wall of the split type pole shoe and the corresponding transition surface and step, and pole teeth are formed on the inner wall of the split type pole shoe; permanent magnets are arranged between the adjacent split pole shoes.
Wherein, the contained angle of transition face and the central axis of axle is 45 degrees.
The pole teeth comprise axial pole teeth and transition pole teeth, the axial pole teeth are arranged on the inner walls of the split pole shoes corresponding to the steps, and the transition pole teeth are arranged on the inner walls of the split pole shoes corresponding to the transition surfaces.
The concave step portion 101 includes 1 first step 1011, 2 second steps 1012 and 2 third steps 1013, diameters of the first step 1011, the second step 1012 and the third step 1013 are sequentially increased, and the 2 second steps 1012 and the 2 third steps 1013 are sequentially symmetrically distributed on both sides of the first step 1011.
The number of the split type pole shoes is 3, namely a first split type pole shoe 19, a second split type pole shoe 17 and a third split type pole shoe 15 which are distributed along the axial direction in sequence, wherein the second split type pole shoe 17 is sleeved outside the first step 1011 and extends to the corresponding transition corresponding positions towards the two sides of the first step; the first split type pole shoe 19 and the third split type pole shoe 15 are respectively arranged at the left side and the right side of the second split type pole shoe 17, the first split type pole shoe 19 is sleeved outside the second step and the third step at the left side of the first step, and the third split type pole shoe 15 is sleeved outside the second step and the third step at the right side of the first step; the inner walls of the first split pole shoe 19, the second split pole shoe 17 and the third split pole shoe 15 are matched with the corresponding steps and the transition surface shape respectively.
The first permanent magnet 8 and the second permanent magnet 10 are respectively arranged between the first split type pole shoe 19 and the second split type pole shoe 17 and between the second split type pole shoe 17 and the third split type pole shoe 15, and the magnetic poles of the adjacent sides of the first permanent magnet 8 and the second permanent magnet 10 are the same.
The inner ring surfaces of the first split pole shoe 19 corresponding to the second step and the third step are respectively provided with a first pole shoe axial pole tooth A5 and a first pole shoe axial pole tooth B7, and the inner wall corresponding to the transition surface between the first split pole shoe 19 and the second step and the third step is provided with a first pole shoe transition pole tooth 6.
The inner wall of the second split pole shoe 17 corresponding to the first step and the corresponding transition surface is provided with second pole shoe pole teeth 9. Correspondingly, the third split pole piece 15 is provided with third pole shoe teeth 11.
The gap size was 2.5mm.
The outer wall of the split pole shoe is provided with an annular groove, and a sealing ring is arranged in the annular groove. Correspondingly, a first sealing ring 20 is arranged in the annular groove of the outer wall of the first split type pole shoe 19, a second sealing ring 18 is arranged in the annular groove of the outer wall of the second split type pole shoe 17, and a third sealing ring 16 is arranged in the annular groove of the outer wall of the third split type pole shoe 15. Preferably, the split pole piece comprises 2 sub pole pieces, which can be combined with each other to form a split pole piece (see fig. 2).
In the single concave stepped part, the outer sides of the first split pole shoe 19 and the third split pole shoe 15 are respectively provided with a first magnetism isolating ring 4 and a second magnetism isolating ring 12.
The number of the bearings is two, namely a first bearing 3 and a second bearing 13, and the bearings are respectively arranged on the outer sides of the first magnetism isolating ring 4 and the second magnetism isolating ring 12.
The end cap 14 is screwed to the right end of the housing 2.
During assembly, the method mainly comprises the following steps of:
(1) Mounting 2 sub-pole pieces of the first split pole piece 19 to the shaft 1 from the upper and lower sides of the shaft 1; the first sealing ring 20 is arranged in a groove on the outer circular surface of the first split pole shoe 19;
mounting the first permanent magnet 8 onto the shaft 1 from the right side;
2 sub pole shoes of the second split pole shoe 17 are arranged on the shaft 1 from the upper side and the lower side of the shaft 1; the second sealing ring 18 is arranged in a groove on the outer circular surface of the second split pole shoe 17;
mounting the second permanent magnet 10 onto the shaft 1 from the right side;
2 sub pole pieces of the third split pole piece 15 are mounted on the shaft 1 from the upper side and the lower side of the shaft 1; the third sealing ring 16 is arranged in a groove on the outer circular surface of the second split pole shoe 15;
(2) Magnetic fluid is injected into a sealing gap formed by the third split type pole shoe 15, the second split type pole shoe 17, the first split type pole shoe 19 and the shaft 1;
(3) The first magnetism isolating ring 4 and the first bearing 3 are sequentially arranged on the shaft 1 from the left side of the shaft;
sequentially mounting a second magnetism isolating ring 12 and a second bearing 13 on the shaft 1 from the right side of the shaft to form a sealing assembly;
(4) The sealing component is arranged in the shell 2, and the outer ring of the right bearing 13 is tightly pressed through the threaded connection of the end cover 14 and the shell 2; the magnetic fluid seal of the concave stepped shaft is realized.
The foregoing examples are set forth in order to provide a more thorough description of the present invention, and are not intended to limit the scope of the invention, since modifications of the invention in various equivalent forms will occur to those skilled in the art upon reading the present invention, and are within the scope of the invention as defined in the appended claims.
Claims (8)
1. A concave stepped shaft magnetic fluid sealing device comprises a shell (2) with two open ends, a sealing component and an end cover (14) for pressing the sealing component into the shell (2); the sealing assembly comprises a shaft (1), wherein the shaft (1) is rotatably arranged in a shell (2) through a bearing, and the sealing assembly is characterized in that the shaft (1) comprises at least one concave step part (101), the concave step part (101) comprises a plurality of steps which are sequentially arranged along the axial direction, and the outer walls of adjacent steps are connected through chamfer-shaped transition surfaces; each transition surface is sleeved with a split type pole shoe matched with the transition surface, the split type pole shoe extends to a position corresponding to a corresponding step at the side part of the transition surface towards one side or two sides of the transition surface, gaps are reserved between the inner wall of the split type pole shoe and the corresponding transition surface and step, and pole teeth are formed on the inner wall of the split type pole shoe and/or on a part, corresponding to the inner wall of the split type pole shoe, of the shaft (1); permanent magnets are arranged between adjacent split pole shoes;
the included angle between the transition surface and the central axis of the shaft is 5-75 degrees;
the pole teeth comprise axial pole teeth and/or transition pole teeth, the axial pole teeth are arranged on the steps and/or on the inner walls of the split pole shoes corresponding to the steps, and the transition pole teeth are arranged on the transition surfaces and/or on the inner walls of the split pole shoes corresponding to the transition surfaces.
2. The concave stepped shaft magnetic fluid sealing device according to claim 1, wherein the concave stepped portion (101) comprises 1 first step (1011), 2 second steps (1012) and 2 third steps (1013), the diameters of the first step (1011), the second step (1012) and the third step (1013) are sequentially increased, and the 2 second steps (1012) and the 2 third steps (1013) are sequentially symmetrically distributed on both sides of the first step (1011).
3. The concave stepped shaft magnetic fluid sealing device according to claim 1, wherein the number of the split pole shoes is 3, namely a first split pole shoe (19), a second split pole shoe (17) and a third split pole shoe (15) which are sequentially distributed along the axial direction, and the second split pole shoe (17) is sleeved outside the first step (1011) and extends to the corresponding transition corresponding positions towards the two sides of the first step; the first split pole shoe (19) and the third split pole shoe (15) are respectively arranged at the left side and the right side of the second split pole shoe (17), the first split pole shoe (19) is sleeved outside the second step and the third step at the left side of the first step, and the third split pole shoe (15) is sleeved outside the second step and the third step at the right side of the first step; the inner walls of the first split pole shoe (19), the second split pole shoe (17) and the third split pole shoe (15) are matched with the corresponding steps and the transition surface shape respectively.
4. A concave stepped shaft magnetic fluid sealing device according to claim 3, characterized in that a first permanent magnet (8) and a second permanent magnet (10) are respectively arranged between the first split pole shoe (19) and the second split pole shoe (17) and between the second split pole shoe (17) and the third split pole shoe (15), and the magnetic poles of adjacent sides of the first permanent magnet (8) and the second permanent magnet (10) are the same.
5. The concave stepped shaft magnetic fluid sealing device according to claim 1, wherein the gap size is 0.05-5mm.
6. The concave stepped shaft magnetic fluid sealing device according to claim 1, wherein an annular groove is formed in the outer wall of the split pole shoe, and a sealing ring is arranged in the annular groove.
7. The concave stepped shaft magnetic fluid sealing device according to claim 1, wherein in the single concave stepped portion, the outer sides of the two pole shoes at the outermost sides are respectively provided with a first magnetism isolating ring (4) and a second magnetism isolating ring (12).
8. The concave stepped shaft magnetic fluid sealing device according to claim 1, wherein the number of the bearings is two, namely a first bearing (3) and a second bearing (13), and the bearings are respectively arranged on two sides of the concave stepped portion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711326996.5A CN107893855B (en) | 2017-12-13 | 2017-12-13 | Concave stepped shaft magnetic fluid sealing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711326996.5A CN107893855B (en) | 2017-12-13 | 2017-12-13 | Concave stepped shaft magnetic fluid sealing device |
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| Publication Number | Publication Date |
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| CN107893855A CN107893855A (en) | 2018-04-10 |
| CN107893855B true CN107893855B (en) | 2023-05-02 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201711326996.5A Active CN107893855B (en) | 2017-12-13 | 2017-12-13 | Concave stepped shaft magnetic fluid sealing device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112178199A (en) * | 2020-09-10 | 2021-01-05 | 上海宇航系统工程研究所 | Magnetic fluid sealing device adopting threaded connection shaft |
Citations (6)
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|---|---|---|---|---|
| DE4127300A1 (en) * | 1991-06-15 | 1993-02-25 | Albrecht Dipl Ing Kayser | COMBINED SLIDE AND SPIRAL GROOVE AXIAL SHAFT SEAL |
| US5826885A (en) * | 1996-10-02 | 1998-10-27 | Rigaku/Usa, Inc. | Magnetic fluid sealing device |
| CN201354756Y (en) * | 2009-01-09 | 2009-12-02 | 龚正勤 | Magnetic fluid shaft seal |
| CN202332310U (en) * | 2011-11-10 | 2012-07-11 | 湖南维格磁流体股份有限公司 | Shielded magnetic fluid sealing device |
| CN103343822A (en) * | 2013-07-05 | 2013-10-09 | 北京交通大学 | Magnetic liquid rotating sealing device suitable for space station |
| CN206600473U (en) * | 2017-01-20 | 2017-10-31 | 北京空间飞行器总体设计部 | A kind of hot joint of rotation based on magnet fluid sealing |
-
2017
- 2017-12-13 CN CN201711326996.5A patent/CN107893855B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4127300A1 (en) * | 1991-06-15 | 1993-02-25 | Albrecht Dipl Ing Kayser | COMBINED SLIDE AND SPIRAL GROOVE AXIAL SHAFT SEAL |
| US5826885A (en) * | 1996-10-02 | 1998-10-27 | Rigaku/Usa, Inc. | Magnetic fluid sealing device |
| CN201354756Y (en) * | 2009-01-09 | 2009-12-02 | 龚正勤 | Magnetic fluid shaft seal |
| CN202332310U (en) * | 2011-11-10 | 2012-07-11 | 湖南维格磁流体股份有限公司 | Shielded magnetic fluid sealing device |
| CN103343822A (en) * | 2013-07-05 | 2013-10-09 | 北京交通大学 | Magnetic liquid rotating sealing device suitable for space station |
| CN206600473U (en) * | 2017-01-20 | 2017-10-31 | 北京空间飞行器总体设计部 | A kind of hot joint of rotation based on magnet fluid sealing |
Non-Patent Citations (1)
| Title |
|---|
| 大间隙聚合型阶梯式磁性液体密封的设计及试验研究;杨小龙;李德才;;真空科学与技术学报(03);第258-262页 * |
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