WO2022041349A1

WO2022041349A1 - Magnetic liquid sealing apparatus having alternately distributed permanent magnet piece and magnetically permeable piece

Info

Publication number: WO2022041349A1
Application number: PCT/CN2020/115992
Authority: WO
Inventors: 李德才; 赵文曦
Original assignee: 清华大学
Priority date: 2020-08-25
Filing date: 2020-09-17
Publication date: 2022-03-03
Also published as: JP2023533611A; CN112145698A; JP7458676B2

Abstract

Disclosed is a magnetic liquid sealing apparatus (8) having an alternately distributed permanent magnet piece (31) and magnetically permeable piece (32); the magnetic liquid sealing apparatus comprises a housing (1), a rotary shaft (2), and a sealing component (3); the rotary shaft penetrates the housing and is rotatable relative to the housing; the sealing component comprises a permanent magnet piece and a magnetically permeable piece; the magnetically permeable piece and the permanent magnet piece are both arranged in the housing and sleeved on the outside of the rotary shaft; the magnetically permeable piece and the permanent magnet piece are alternately arranged along the axial direction of the rotary shaft, and the adjacent magnetically permeable sheet and permanent magnet sheet are tightly joined to each other; the inner circumferential surface of the magnetically permeable piece and the outer circumferential surface of the rotary shaft have a sealing gap in the radial direction of the rotary shaft, and there is a magnetic liquid in the sealing gap. The magnetic liquid sealing apparatus has a uniformly distributed magnetic field, strong adsorption capacity for magnetic liquids, can be configured at a higher level of sealing, has low machining and maintenance costs, and prevents situations in which the magnetic liquid is far away from the sealing gap, and has reliable sealing performance.

Description

Magnetic liquid sealing device with alternating distribution of permanent magnet pieces and magnetic conductive pieces

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority and rights of the Chinese patent application with the application number of 202010862984.X and the filing date of August 25, 2020. The entire contents of the above Chinese patent application are hereby incorporated by reference into this application.

technical field

The embodiments of the present application relate to the technical field of mechanical engineering sealing, and more particularly, to a magnetic liquid sealing device in which permanent magnet sheets and magnetic conductive sheets are alternately distributed.

Background technique

Magnetic liquid seal is a new type of non-contact seal, which utilizes the characteristics of both fluidity and magnetic field responsiveness of magnetic liquid. By forming a magnetic field gradient in the sealing gap, the magnetic liquid can be sealed under the combined action of pressure and magnetic field force. A number of "O-shaped" liquid sealing rings are formed in the gap to achieve the effect of sealing and pressure resistance, and have the advantages of "zero leakage", long life and high reliability.

In the related art, the magnetic liquid sealing device includes left and right pole pieces and a permanent magnet disposed therebetween. The pole pieces are slotted to form pole teeth, and the magnetic liquid is adsorbed on the pole teeth to form a seal. When the pressure resistance requirements become higher and the number of sealing stages increases, the number of pole teeth needs to be increased, but the increase in the number of pole teeth will lead to uneven distribution of the magnetic liquid among the pole teeth, and the use efficiency of the magnetic liquid and permanent magnets will decrease; In addition, in the case of large-diameter and high-speed sealing, the magnetic liquid climbs along the pole teeth under the action of large centrifugal force, and gradually moves away from the sealing gap, which reduces the volume of magnetic liquid in the sealing gap, and even a gap appears between the pole teeth and the shaft. Decreased pressure resistance.

SUMMARY OF THE INVENTION

The present application aims to solve one of the technical problems in the related art at least to a certain extent.

To this end, the embodiments of the present application propose a magnetic liquid sealing device in which permanent magnet sheets and magnetic conductive sheets are alternately distributed, the magnetic liquid of the magnetic liquid sealing device is evenly distributed in the sealing gap, and avoids the magnetic liquid being far from the sealing gap. situation happens.

The magnetic liquid sealing device according to the embodiment of the present application includes a casing, a rotating shaft and a sealing assembly, the rotating shaft passing through the casing and rotatable relative to the casing, the sealing assembly includes a permanent magnet sheet and a magnetic conducting sheet, the conducting The magnetic sheet and the permanent magnet sheet are both arranged in the outer casing and sleeved on the outside of the rotating shaft, the magnetic conducting sheet and the permanent magnet sheet are alternately arranged along the axial direction of the rotating shaft, and the permanent magnet There are said magnetic conductive sheets on both sides of the sheet oppositely arranged in the axial direction of the rotating shaft, and the adjacent magnetic conductive sheets and the permanent magnet sheets are closely attached, and the inner part of the magnetic conductive sheet The circumferential surface and the outer circumferential surface of the rotating shaft have a sealing gap in the radial direction of the rotating shaft, and the sealing gap has a magnetic liquid for sealing. The permanent magnet pieces between the magnetic conductive pieces, the rotating shaft and the magnetic liquid form a magnetic circuit.

According to the magnetic liquid sealing device in which the permanent magnet sheets and the magnetic conductive sheets are alternately distributed according to the embodiment of the present application, the magnetic field distribution is uniform, the adsorption capacity for the magnetic liquid is stronger, and the magnetic liquid is uniformly distributed in the sealing gap. High sealing level. In addition, since the present application adopts the alternate arrangement of magnetic conductive sheets and permanent magnet sheets, compared with the pole-shoe and pole-tooth structure in the prior art, the present application has low processing cost and avoids the situation that the magnetic liquid is far from the sealing gap. occurs, the sealing performance is more reliable.

In some embodiments, the inner peripheral surface of the permanent magnet piece and the outer peripheral surface of the rotating shaft have a gap in the radial direction of the rotating shaft.

In some embodiments, the permanent magnet sheet and the magnetic conductive sheet are both annular, and the inner diameter of the permanent magnet sheet and the inner diameter of the magnetic conductive sheet are the same.

In some embodiments, the size of the magnetic conductive sheet in the axial direction of the rotating shaft is 0.25-0.35 mm, and the size of the permanent magnet sheet in the axial direction of the rotating shaft is 0.6-3 mm.

In some embodiments, the magnetic liquid sealing device in which the permanent magnet sheets and the magnetic conductive sheets are alternately distributed further includes a first magnetic isolation ring and a second magnetic isolation ring, and both the first magnetic isolation ring and the second magnetic isolation ring are The first magnetic isolation ring is provided on the first end of the sealing component, and the second magnetic isolation ring is provided on the second end of the sealing component.

In some embodiments, the magnetic liquid sealing device in which the permanent magnet sheets and the magnetic conductive sheets are alternately distributed further includes a first bearing and a second bearing, both of which are arranged in the housing and are connected to the housing. The rotating shaft is matched, the first bearing is arranged on the side of the first magnetic isolation ring away from the sealing assembly, and the second bearing is arranged at the side of the second magnetic isolation ring away from the sealing assembly .

In some embodiments, the housing includes a barrel and an end cap, the barrel having a cavity, the barrel having an open first end disposed to open the first end of the cavity, so The end cap is provided at the first end of the cylindrical member to close the first end of the cavity, and the rotating shaft penetrates through the end cap.

In some embodiments, the rotating shaft is provided with a first retaining ring and a second retaining ring, the first retaining ring and the second retaining ring are both arranged around the rotating shaft, and the first retaining ring is located at the between the first bearing and the first end of the housing, and the second retaining ring is located between the second bearing and the second end of the housing.

In some embodiments, the material of the magnetic conductive sheet is silicon steel.

In some embodiments, the material of the first magnetic isolation ring, the material of the second magnetic isolation ring, and the material of the housing are all non-magnetic conductive materials.

Description of drawings

1 is a schematic diagram of a magnetic liquid sealing device in which permanent magnet sheets and magnetic conductive sheets are alternately distributed according to an embodiment of the present application;

FIG. 2 is a partial enlarged view A of a magnetic liquid sealing device in which permanent magnet sheets and magnetic conductive sheets are alternately distributed according to an embodiment of the present application.

Reference number:

Housing 1, cylindrical member 11, end cap 12, flange 13, sealing ring 14,

Rotating shaft 2, first retaining ring 21, second retaining ring 22,

Sealing assembly 3, permanent magnet piece 31, magnetic conductive piece 32,

The first magnetic isolation ring 4,

The second magnetic isolation ring 5,

first bearing 6,

second bearing 7,

Magnetic liquid 8.

detailed description

Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to be used to explain the present application, but should not be construed as a limitation to the present application. In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", " Rear, Left, Right, Vertical, Horizontal, Top, Bottom, Inner, Outer, Clockwise, Counterclockwise, Axial, The orientations or positional relationships indicated by "radial direction", "circumferential direction", etc. are based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying the indicated devices or elements. The clamp must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as a limitation of the present application.

As shown in FIG. 1 , the magnetic liquid 8 sealing device according to the embodiment of the present application includes a housing 1 , a rotating shaft 2 and a sealing assembly 3 . The rotating shaft 2 penetrates through the casing 1 and is rotatable relative to the casing 1 . As shown in FIG. 1 , the rotating shaft 2 extends in the left-right direction, that is, the axial direction of the rotating shaft 2 is the left-right direction, and the rotating shaft 2 penetrates the casing 1 along the left-right direction. Specifically, the material of the rotating shaft 2 is a magnetically conductive material, and the material of the housing 1 is a non-magnetically conductive material.

The sealing assembly 3 is provided in the casing 1 to perform a sealing function.

As shown in FIG. 2 , specifically, the sealing assembly 3 includes a magnetic conductive sheet 32 and a permanent magnet sheet 31 , and the magnetic conductive sheet 32 and the permanent magnet sheet 31 are both sleeved on the outside of the rotating shaft 2 . The magnetic conductive sheets 32 and the permanent magnet sheets 31 are alternately arranged along the axial direction of the rotating shaft 2 , and the magnetic conductive sheets 32 are provided on both sides of the permanent magnet sheets 31 oppositely arranged in the axial direction of the rotating shaft 2 . In other words, both sides of each permanent magnet piece 31 are provided with magnetic conductive pieces 32, the number of permanent magnet pieces 31 is at least one, and the number of magnetic conductive pieces 32 is one more than the number of permanent magnet pieces 31.

Further, the adjacent magnetic conductive sheets 32 and the permanent magnet pieces 31 are closely attached, that is, there is no gap between the magnetic conductive sheets 32 and the permanent magnet pieces 31 . Specifically, the magnetic conductive sheet 32 and the permanent magnet sheet 31 can be bonded together by adhesive, or pressure is applied on both sides to make them closely fit. Of course, other methods can also be used, as long as the magnetic conductive sheet is ensured 32 and the permanent magnet piece 31 can be closely attached.

As shown in FIG. 2 , the inner peripheral surface of the magnetic conductive sheet 32 and the outer peripheral surface of the rotating shaft 2 have a sealing gap in the radial direction of the rotating shaft 2 , and the inner peripheral surface of the magnetic conductive sheet 32 and the outer peripheral surface of the rotating shaft 2 are in the radial direction of the rotating shaft 2 The distance is 0.001mm-1mm, and there is a magnetic liquid 8 for sealing in the sealing gap. The type of magnetic liquid 8 can be selected according to the type of sealing gas/liquid and the range of ambient temperature in the actual working conditions. The magnetic properties of different base carrier liquids For liquids, ester-based magnetic liquid or silicone oil-based magnetic liquid can be selected for general vacuum sealing, and silicone oil-based magnetic liquid can be selected for low-temperature sealing.

The two adjacent magnetic conductive sheets 32, the permanent magnet pieces 31 located between the two adjacent magnetic conductive sheets 32, the rotating shaft 2 and the magnetic liquid 8 form a magnetic circuit, and a magnetic field is formed on the magnetic conductive sheets 32, so that The magnetic liquid 8 is adsorbed on the outer peripheral surface of the magnetic conductive sheet 32 under the action of the magnetic field force, so as to fill the sealing gap and play a sealing role.

It should be noted that, when the number of permanent magnet pieces 31 is one, the number of magnetic conductive pieces 32 is two and they are respectively arranged on both sides of the permanent magnet piece 31, and the magnetic field is emitted from the interior of the permanent magnet and passes through one magnetic conductive piece in turn. 32. The magnetic liquid 8, the rotating shaft 2 and the other magnetic conductive sheet 32 form a closed magnetic field. When the number of permanent magnet pieces 31 is multiple, each permanent magnet piece 31 forms a plurality of closed magnetic fields correspondingly, and the number of closed magnetic fields is the same as the number of permanent magnet pieces 31 .

According to the magnetic liquid sealing device in which the permanent magnet sheets and the magnetic conductive sheets are alternately distributed in the embodiment of the present application, a strong magnetic field can be formed on each magnetic conductive sheet 32 , and the magnetic field distribution is uniform, and the adsorption capacity of the magnetic liquid 8 is stronger. , and the magnetic liquid 8 is evenly distributed in the sealing gap, and a higher sealing stage can be set according to the pressure resistance requirement. In addition, since the present application adopts the alternate arrangement of the magnetic conductive sheet 32 and the permanent magnet sheet 31, compared with the pole-shoe and pole-tooth structure in the prior art, the present application has low production cost, simple installation process, and can be easily damaged after partial damage. , it is only necessary to replace the partial magnetic conductive sheet 32 or the permanent magnet, and the maintenance cost is low.

In some embodiments, the inner peripheral surface of the permanent magnet piece 31 and the outer peripheral surface of the rotating shaft 2 have a gap in the radial direction of the rotating shaft 2 . It should be noted that the gap between the inner peripheral surface of the permanent magnet piece 31 and the outer peripheral surface of the rotating shaft 2 is to facilitate the flow of the magnetic liquid 8 between the sealing gaps, and this gap is different from the sealing gap, because the magnetic field mainly concentrates On the magnetic conductive sheet 32, and the magnetic field at the edge of the magnetic conductive sheet 32 is strong, a gradient magnetic field is formed in the sealing gap, and the magnetic liquid 8 reaches a balanced state under the combined action of the pressure difference and the magnetic field force, and will not move further. , so that the magnetic liquid 8 is kept in the sealing gap to form a seal.

Further, the permanent magnet pieces 31 and the magnetic conductive pieces 32 are both annular, that is, the permanent magnet pieces 31 and the magnetic conductive pieces 32 both have an inner diameter and an outer diameter. In some embodiments, the inner diameter of the permanent magnet sheet 31 is the same as the inner diameter of the magnetic conductive sheet 32, so that the inner peripheral surface of the permanent magnet sheet 31 and the inner peripheral surface of the magnetic conductive sheet 32 are flush to form a cylindrical inner surface. Even if the rotating shaft 2 rotates at a high speed, the magnetic liquid 8 will not climb from the inside to the outside along the radial direction of the magnetic conductive sheet 32, but will always be located in the sealing gap. Therefore, the sealing performance of the magnetic liquid sealing device of the embodiment of the present application more reliable. Moreover, since the magnetic conductive sheet 32 and the permanent magnet sheet 31 are closely attached, the situation of the magnetic liquid 8 climbing outwards can be further avoided.

Preferably, the outer diameter of the permanent magnet sheet 31 is the same as the outer diameter of the magnetic conductive sheet 32, thereby facilitating the alignment and bonding of the permanent magnet sheet 31 and the magnetic conductive sheet 32, and convenient installation.

In some embodiments, the size of the magnetic conductive sheet 32 in the axial direction of the rotating shaft 2 is 0.25-0.35 mm, and the size of the permanent magnet sheet 31 in the axial direction of the rotating shaft 2 is 0.6-3 mm. It can be understood that the size of the magnetic conductive sheet 32 and the permanent magnet sheet 31 in the upward direction of the rotating shaft 2 refers to the thickness of the magnetic conductive sheet 32 and the thickness of the permanent magnet sheet 31. Within the above size range, the permanent magnet sheet 31 can provide sufficient The magnetic field strength of the magnetic conductive sheet 32 can replace the role of the pole piece and the pole teeth, and a strong magnetic field is formed in the sealing gap. 8 is confined within the sealing gap, forming a seal.

As shown in FIG. 2 , in some embodiments, the magnetic liquid 8 sealing device further includes a first magnetic isolation ring 4 and a second magnetic isolation ring 5 , and the first magnetic isolation ring 4 and the second magnetic isolation ring 5 are both provided in the casing 1 and sleeved on the outside of the rotating shaft 2, the first magnetic isolation ring 4 is set at the first end of the sealing assembly 3 (the left end of the sealing assembly 3 in FIG. 1), and the second magnetic isolation ring 5 is set at the The second end (the right end of the seal assembly 3 in FIG. 1 ). As shown in FIG. 1 , the first magnetic isolation ring 4 is provided at the left end of the sealing assembly 3 , and the second magnetic isolation ring 5 is provided at the right end of the sealing assembly 3 . Specifically, the materials of the first magnetic isolation ring 4 and the second magnetic isolation ring 5 are both non-magnetic conductive materials, such as demagnetized 304 stainless steel or aluminum alloy materials.

The first magnetic isolation ring 4 and the second magnetic isolation ring 5 are used to isolate the sealing assembly 3 from other components, so as to prevent the magnetic field on the magnetic conductive ring from interacting with the magnetic properties of other components, resulting in the sealing of the sealing device. Performance drops.

In some embodiments, the magnetic liquid sealing device further includes a first bearing 6 and a second bearing 7 . The first bearing 6 and the second bearing 7 are both arranged in the casing 1 and cooperate with the rotating shaft 2 , so as to realize the rotating shaft 2 and the casing 1 . relative rotation. The first bearing 6 is provided on the side of the first magnetic isolation ring 4 away from the sealing assembly 3 (the left side of the first magnetic isolation ring 4 in FIG. 1 ), and the second bearing 7 is provided on the second magnetic isolation ring 5 away from the sealing assembly. 3 (right side of the second magnetic isolation ring 5 in Figure 1). In other words, the first magnetic isolation ring 4 is provided between the first bearing 6 and the sealing assembly 3 , and the second magnetic isolation ring 5 is provided between the second bearing 7 and the sealing assembly 3 .

The model of the first bearing 6 and the model of the second bearing 7 can be selected according to the magnitude of the axial force under actual working conditions, such as deep groove ball bearings or angular contact bearings.

In some embodiments, the housing 1 includes a cylindrical member 11 and an end cap 12, the cylindrical member 11 has a cavity, and the first end of the cylindrical member 11 (the left end of the cylindrical member 11 as shown in FIG. 1 ) is open and disposed In order to make the first end of the cavity open, the end cover 12 is provided at the first end of the cylindrical member 11 to close the first end of the cavity, and the rotating shaft 2 penetrates through the end cover 12 and the second end of the cylindrical member 11 (such as the right end of the cylindrical member 11 shown in FIG. 1).

When assembling the magnetic liquid sealing device in which the permanent magnet pieces and the magnetic conductive pieces are alternately distributed, the rotating shaft 2 with the retaining ring can be inserted through the cylindrical member 11 first, and then the second bearing 7 and the second magnetic isolation ring 5 can be installed in sequence on the On the rotating shaft 2, then the sealing assembly 3 is sleeved on the rotating shaft 2 according to the alternating sequence of the magnetic conductive sheet 32 and the permanent magnet sheet 31, and then the first magnetic isolation ring 4 and the first bearing 6 are installed on the rotating shaft 2, and finally the The end cover 12 only needs to be installed on the first end of the cylindrical member 11 , and the end cover 12 and the cylindrical member 11 are connected by a connecting member, and the connecting member can be a bolt.

It should be noted that the outer diameter of the magnetic conductive sheet 32 and the outer diameter of the permanent magnet sheet 31 are preferably the same as the inner diameter of the cylindrical member 11 , so that the sealing assembly 3 cannot follow the radial direction of the cylindrical member 11 in the cylindrical member 11 . move.

The outer circumference of the first end of the cylindrical member 11 is provided with a flange 13, and a through hole is opened on the flange 13, so that the magnetic liquid 8 sealing device can be fixed on the installation surface of other components, and the end face of the first end of the flange 13 is provided. An annular groove is opened on the upper part, and a sealing ring 14 is arranged in the annular groove to ensure the air tightness between the housing 1 and the installation surfaces of other components. In addition, an annular groove is also provided on the end cover 12, and the annular groove is used for centering during installation, which is convenient for installation.

In some embodiments, the rotating shaft 2 is provided with a first retaining ring 21 and a second retaining ring 22 , the first retaining ring 21 and the second retaining ring 22 are both arranged around the rotating shaft 2 , and the first retaining ring 21 is located on the first bearing 6 Between the first end of the housing 1 (the left end of the housing 1 as shown in FIG. 1 ), the second retaining ring 22 is located between the second bearing 7 and the second end of the housing 1 (the right end of the housing 1 as shown in FIG. 1 ), The first retaining ring 21 and the second retaining ring 22 are used to limit the axial movement of the rotating shaft 2 and prevent it from slipping off in the axial direction.

Optionally, in some other embodiments, the number of retaining rings can also be one, for example, only the first retaining ring 21 or only the second retaining ring 22 is provided, as long as it can limit the axial movement of the rotating shaft 2 That's it.

In some embodiments, the material of the magnetic conductive sheet 32 is silicon steel, which refers to silicon alloy steel with a silicon content of 1.0-4.5% and a carbon content of less than 0.08%. Silicon steel has the characteristics of high magnetic permeability, low coercive force, large resistivity, etc., and the hysteresis loss and eddy current loss are very small. Therefore, silicon steel is used as the material of the magnetic conductive sheet 32, and the magnetic conductive sheet 32 is preferably a silicon steel sheet, a silicon steel sheet It is a common material mainly used to make iron cores of various transformers, motors and generators.

The following describes a magnetic liquid sealing device in which permanent magnet sheets and magnetic conductive sheets are alternately distributed according to some specific examples of the present application with reference to FIGS. 1-2 .

As shown in FIG. 1 , the magnetic liquid sealing device in which the permanent magnet sheets and the magnetic conductive sheets are alternately distributed according to the embodiment of the present application includes a casing 1 , a rotating shaft 2 and a sealing assembly 3 , and the casing 1 includes a cylindrical member 11 and an end cover 12 . The first end of the shaped member 11 is open, the end cover 12 is provided at the opening, the end cover 12 and the cylindrical member 11 are connected by bolts, the rotating shaft 2 is arranged through the second end of the end cover 12 and the cylindrical member 11, and the sealing assembly 3 is provided inside the housing 1.

As shown in FIG. 2 , the sealing assembly 3 includes a magnetic conductive sheet 32 and a permanent magnet sheet 31. The material of the magnetic conductive sheet 32 is silicon steel. The pieces 32 and the permanent magnet pieces 31 are alternately arranged along the axial direction of the rotating shaft 2 . The number of the permanent magnet pieces 31 is 16 and the number of the magnetic conducting pieces 32 is 17. Each permanent magnet piece 31 is opposite to the axial direction of the rotating shaft 2 . There are magnetic conductive sheets 32 on both sides of the arrangement, and the adjacent permanent magnet pieces 31 and the magnetic conductive sheets 32 are adhered together by adhesive and closely attached.

The magnetic conductive sheet 32 and the permanent magnet sheet 31 are both annular, and the outer diameter of the magnetic conductive sheet 32 is the same as the outer diameter of the permanent magnet sheet 31, and the inner diameter of the magnetic conductive sheet 32 is the same as the inner diameter of the permanent magnet sheet 31. The magnetic conductive sheet 32 The inner peripheral surface of the rotary shaft 2 and the outer peripheral surface of the rotating shaft 2 have a sealing gap in the radial direction of the rotating shaft 2, and there is a magnetic liquid 8 for sealing in the sealing gap.

The outer diameter of the magnetic conductive sheet 32 and the outer diameter of the permanent magnet sheet 31 are the same as the inner diameter of the cylindrical member 11 , the outer peripheral surface of the magnetic conductive sheet 32 is in contact with the inner peripheral surface of the cylindrical member 11 , and the outer peripheral surface of the permanent magnet sheet 31 is in contact with each other. The surface is in contact with the inner peripheral surface of the cylindrical member 11 .

The first end of the sealing assembly 3 is sequentially provided with a first magnetic isolation ring 4 and a first bearing 6 along the direction away from the sealing assembly 3 , and the second end of the sealing assembly 3 is sequentially provided with a second magnetic isolation along the direction away from the sealing assembly 3 . The ring 5 and the second bearing 7, the first bearing 6 and the second bearing 7 cooperate with the rotating shaft 2 to realize the relative rotation of the rotating shaft 2 and the casing 1, and the first magnetic isolation ring 4 separates the first bearing 6 from the sealing assembly 3, The second magnetic isolation ring 5 separates the second bearing 7 from the sealing assembly 3 .

The rotating shaft 2 is provided with a retaining ring, the retaining ring is arranged around the rotating shaft 2, and the retaining ring is located between the second bearing 7 and the end of the housing 1 to prevent the rotating shaft 2 from moving axially.

According to the magnetic liquid sealing device of the embodiment of the present application, alternately arranged magnetic conductive sheets 32 and permanent magnet sheets 31 are used to replace the pole-shoe and pole-tooth structure in the prior art, and a magnetic field gradient exists in the sealing gap, so that the magnetic liquid 8 is pressed The balance state is achieved under the combined action of the difference and the magnetic field force, so that the magnetic liquid 8 is kept in the sealing gap to form a reliable seal, which solves the problem that the magnetic liquid 8 climbs along the pole teeth radially by centrifugal force in the prior art, and is easy to assemble , low maintenance cost.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other.

Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limitations to the present application. Embodiments are subject to variations, modifications, substitutions and variations.

Claims

A magnetic liquid sealing device in which permanent magnet sheets and magnetic conductive sheets are alternately distributed, characterized in that, comprising:

shell;

a rotating shaft, which penetrates through the casing and is rotatable relative to the casing;

A sealing assembly, the sealing assembly includes a permanent magnet sheet and a magnetic conductive sheet, the magnetic conductive sheet and the permanent magnet sheet are both arranged in the outer casing and sleeved on the outer side of the rotating shaft, the magnetic conductive sheet and The permanent magnet pieces are alternately arranged along the axial direction of the rotating shaft, and the magnetic conducting pieces are arranged on both sides of the permanent magnet pieces that are oppositely arranged in the axial direction of the rotating shaft, and the adjacent magnetic conducting pieces are arranged on both sides. It is in close contact with the permanent magnet sheet, the inner peripheral surface of the magnetic conductive sheet and the outer peripheral surface of the rotating shaft have a sealing gap in the radial direction of the rotating shaft, and the sealing gap has a magnetic seal for sealing. The liquid, the two adjacent magnetic conductive sheets, the permanent magnet sheet located between the adjacent two magnetic conductive sheets, the rotating shaft and the magnetic liquid form a magnetic circuit.
The magnetic liquid sealing device of claim 1, wherein the inner peripheral surface of the permanent magnet sheet and the outer peripheral surface of the rotating shaft have a radial direction of the rotating shaft. gap.
The magnetic liquid sealing device in which the permanent magnet pieces and the magnetic conductive pieces are alternately distributed according to claim 1 or 2, wherein the permanent magnet pieces and the magnetic conductive pieces are both annular, and the inner diameter of the permanent magnet piece is It is the same as the inner diameter of the magnetic conductive sheet.
The magnetic liquid sealing device in which the permanent magnet pieces and the magnetic conductive pieces are alternately distributed according to any one of claims 1 to 3, wherein the size of the magnetic conductive pieces in the axial direction of the rotating shaft is 0.25- 0.35mm, and the dimension of the permanent magnet piece in the axial direction of the rotating shaft is 0.6-3mm.
The magnetic liquid sealing device in which the permanent magnet sheets and the magnetic conductive sheets are alternately distributed according to any one of claims 1 to 4, further comprising a first magnetic isolation ring and a second magnetic isolation ring, the first magnetic isolation ring The magnetic isolation ring and the second magnetic isolation ring are both arranged on the outer casing and sleeved on the outside of the rotating shaft, the first magnetic isolation ring is arranged on the first end of the sealing assembly, and the second magnetic isolation ring A ring is provided at the second end of the seal assembly.
The magnetic liquid sealing device in which the permanent magnet sheets and the magnetic conducting sheets are alternately distributed according to any one of claims 1-5, further comprising a first bearing and a second bearing, the first bearing and the The second bearings are all arranged in the housing and cooperate with the rotating shaft, the first bearings are arranged on the side of the first magnetic isolation ring away from the sealing assembly, and the second bearings are arranged on the first magnetic isolation ring. The second magnetic isolation ring is away from one side of the sealing assembly.
The magnetic liquid sealing device in which the permanent magnet pieces and the magnetic conducting pieces are alternately distributed according to any one of claims 1 to 6, wherein the housing comprises a cylindrical member and an end cover, and the cylindrical member has a hollow space. a cavity, the first end of the cylindrical member is open and disposed to open the first end of the cavity, and the end cap is disposed on the first end of the cylindrical member to close the first end of the cavity , the rotating shaft penetrates the end cover.
The magnetic liquid sealing device in which the permanent magnet pieces and the magnetic conductive pieces are alternately distributed according to claim 6 or 7, wherein a first retaining ring and a second retaining ring are arranged on the rotating shaft, and the first retaining ring is Both the second retaining ring and the second retaining ring are arranged around the rotating shaft, the first retaining ring is located between the first bearing and the first end of the housing, and the second retaining ring is located between the second bearing and the housing. between the second ends of the housing.
The magnetic liquid sealing device in which the permanent magnet pieces and the magnetic conductive pieces are alternately distributed according to any one of claims 1 to 8, wherein the material of the magnetic conductive pieces is silicon steel.
The magnetic liquid sealing device in which the permanent magnet sheets and the magnetic conducting sheets are alternately distributed according to any one of claims 1 to 9, wherein the material of the first magnetic isolation ring, the material of the second magnetic isolation ring Both the material and the material of the casing are non-magnetic conductive materials.