A magnetic fluid dynamic sealing device

Abstract

The present invention discloses a magnetofluidic sealing device, comprising a base, a magnetofluid seal, and at least two groups of radial support structures; in the present invention, the roller support is in contact with the main shaft only in multiple local areas and is installed through the action of pre-tightening force, so as to ensure the positioning accuracy between the rotating shaft and the magnetofluid seal; by adjusting the pre-tightening force, the gap in each part of the circumferential direction can be ensured to be uniform while allowing the rotating shaft to rotate freely; the base of the bellows-shaped structure allows the magnetofluid seal installed thereon to have a small range of radial deflection as a whole while bearing the axial load; when the rotating shaft deflects under the action of the eccentric load, the magnetofluid seal can swing precisely and synchronously with the rotating shaft under the driving action of the roller support, thereby ensuring that the sealing gap between the sleeve on the rotating shaft and the pole shoe in the magnetofluid seal remains constant, and effectively avoiding the collision between the sleeve and the pole shoe due to the radial swing of the rotating shaft.

Description

Technical Field

[0001] The present invention relates to the technical field of rotating shaft dynamic sealing of rotating machinery, and in particular to a magnetohydrodynamic sealing device. Background Art

[0002] Magnetic fluid seals utilize magnetic forces acting on a magnetic fluid in a magnetic field to form a liquid O-ring in the tiny gap between the annular pole piece and the rotating shaft, sealing the gas. Due to their zero leakage and minimal wear characteristics, magnetic fluid seals are widely used in aerospace, defense, chemical, petroleum, instrumentation, and other fields.

[0003] In a magnetic fluid dynamic seal, the size of the sealing gap between the pole piece and the rotating shaft is a key factor in determining the sealing performance of the magnetic fluid. Under the action of the same permanent magnet, the larger the sealing gap between the pole piece and the rotating shaft, the lower the magnetic field strength within the gap, the weaker the magnetic restraint force on the magnetic fluid within the gap, and the lower the sealing performance. Therefore, to ensure sufficient sealing performance of the magnetic fluid dynamic seal, the sealing gap between the pole piece and the rotating shaft must be kept sufficiently small.

[0004] In small-diameter, light-load dynamic seals, high-precision rolling bearings are typically installed between the pole shoe base and the shaft to ensure a sufficiently small clearance between them. However, for large-diameter shafts in heavy rotating machinery, custom bearing systems are often required to provide radial and axial positioning and withstand the significant radial loads. Due to the significant radial eccentric loads, the shaft inevitably experiences periodic runout relative to the base.

[0005] In existing dynamic shaft seals for heavy-loaded rotating machinery, to prevent collisions between the pole shoes mounted on the base and the deflecting shaft, the shaft deflection is reduced by increasing the stiffness of the bearing system, while the sealing gap between the pole shoes and the shaft is increased. For large-diameter shafts subjected to heavy loads, increasing the stiffness of custom bearing systems significantly increases the installation space occupied by the bearing system and the design and manufacturing costs. Increasing the sealing gap between the pole shoes and the shaft significantly reduces the sealing capability of the magnetic fluid. Furthermore, the periodic deflection of the shaft causes periodic fluctuations in the sealing gap between the shaft and the pole shoes, further increasing the localized instantaneous sealing gap, making it difficult to ensure the sealing stability of the magnetic fluid.

[0006] Therefore, a magnetohydrodynamic sealing device is developed to solve the above problems. Summary of the Invention

[0007] The purpose of the present invention is to design a magnetic fluid dynamic sealing device in order to solve the above problems.

[0008] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0009] A magnetic fluid dynamic sealing device, wherein a sleeve is sleeved on a rotating shaft, and the magnetic fluid dynamic sealing device comprises:

[0010] Base; a first end of the base is fixedly mounted on the fixed structure;

[0011] A magnetic fluid seal; the magnetic fluid of the magnetic fluid seal is arranged around the sleeve; the first end of the magnetic fluid seal is connected to the second end of the base;

[0012] At least two groups of radial support structures; at least two groups of radial support structures are evenly distributed around the rotating shaft; the radial support structure includes a roller support, the arc surface roller support is fixed to the second end of the magnetic fluid seal, and the rolling body of the roller support is rollingly connected to the rotating shaft.

[0013] Specifically, the roller support includes a cavity, multiple rolling elements, a retaining frame, and a cover plate. An annular rolling groove is provided in the cavity, multiple rolling elements are installed on the retaining frame, and multiple rolling elements are placed in the annular rolling groove so as to be cyclically movable. The first side and upper openings of the cavity are provided, and the cover plate is installed on the upper opening of the cavity. At least one rolling element partially protrudes from the side wall of the cavity and is rollingly connected to the rotating shaft.

[0014] Preferably, the first side of the cavity is an arc surface.

[0015] Furthermore, the radial support structure also includes a wedge-shaped pressure block and a guide rail. The guide rail is fixedly mounted on the second end face of the magnetic fluid seal. The cavity is slidably mounted on the guide rail. A first inclined surface is provided on the second side of the cavity. The first inclined surface and the second inclined surface of the cavity are arranged opposite to each other. Correspondingly, a second inclined surface is provided on the first side of the wedge-shaped pressure block. The distance between the upper end of the second inclined surface and the rotating shaft is smaller than the distance between the lower end of the second inclined surface and the rotating shaft. The first inclined surface and the second inclined surface are wedged together. The wedge-shaped pressure block and the magnetic fluid seal are connected by at least one bolt.

[0016] Furthermore, a dovetail groove is provided at the bottom of the cavity, and a dovetail strip is provided at the upper portion of the guide rail, and the dovetail strip can be slidably placed in the dovetail groove.

[0017] Preferably, the wedge-shaped pressure block is connected to the magnetic fluid seal by two bolts.

[0018] Furthermore, the base is formed into a bellows-shaped structure.

[0019] Furthermore, the magnetic fluid seal includes a sealing seat, a permanent magnet, a pole shoe, and a sealing cover plate. The sealing seat is formed into a barrel-shaped structure. A through hole is provided at the bottom of the sealing seat. The sleeve is arranged through the through hole on the bottom. The permanent magnet, the pole shoe, and the sealing cover plate are all formed into a ring shape. The permanent magnet is installed between the two pole shoes. The inner rings of the two pole shoes are connected to the outer wall of the sleeve through the magnetic fluid. The bottom of the first pole shoe is connected to the bottom of the sealing seat, and the top of the second pole shoe is connected to the bottom of the sealing cover plate. The first end of the sealing cover plate is placed in the sealing seat, and the second end of the sealing cover plate is placed outside the sealing seat and fixedly connected to the end of the sealing seat. The radial support structure is installed on the second end of the sealing cover plate.

[0020] Furthermore, the pole shoe is an annular structure with a tooth-shaped protrusion on the inner side, and the magnetic fluid is located in the gap between the tooth-shaped protrusion of the pole shoe and the shaft sleeve.

[0021] Furthermore, the magnetic fluid seal also includes a pole shoe sealing ring, which is arranged between the outer ring of the pole shoe and the inner wall of the sealing seat.

[0022] The beneficial effects of the present invention are:

[0023] In the present invention, the roller support is only in contact with the main shaft in multiple local areas and is installed through the action of pre-tightening force, which is convenient for ensuring the positioning accuracy between the rotating shaft and the magnetic fluid seal. At the same time, it takes up little space, has low cost and is easy to install. By adjusting the pre-tightening force, the gap in the circumferential direction can be guaranteed to be uniform while allowing the rotating shaft to rotate freely. The base of the bellows-shaped structure allows the magnetic fluid seal installed thereon to have a small range of radial deflection as a whole while bearing the axial load. When the rotating shaft deflects under the action of eccentric load, the magnetic fluid seal can swing precisely and synchronously with the rotating shaft under the driving action of the roller support, ensuring that the sealing gap between the sleeve on the rotating shaft and the pole shoe in the magnetic fluid seal remains constant, effectively avoiding the collision between the sleeve and the pole shoe due to the radial swing of the rotating shaft, the designed sealing gap can be greatly reduced, and the sealing ability and sealing stability can be greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a cross-sectional view of the present invention;

[0025] Figure 2 is a cross-sectional view of the magnetic fluid seal of the present invention;

[0026] Figure 3 is a cross-sectional view of the roller support in the present invention;

[0027] Figure 4 is a transverse cross-sectional view of the roller support of the present invention;

[0028] In the figure: 1 base, 2 magnetic fluid seal, 3 roller support, 4 wedge-shaped pressure block, 5 pre-tightening screw, 6 connecting screw, 7 base sealing ring, 8 rotating shaft;

[0029] 2-1 sealing seat, 2-2 pole shoe sealing ring, 2-3 permanent magnet, 2-4 pole shoe, 2-5 magnetic fluid, 2-6 sealing cover, 2-7 cover screw, 2-8 shaft sleeve, 2-9 expansion sleeve, 2-10 pressure ring, 2-11 pressure ring screw, 2-12 shaft sleeve sealing ring;

[0030] 3-1 cavity, 3-2 guide rail, 3-3 rolling element, 3-4 retaining frame, 3-5 cover plate. DETAILED DESCRIPTION

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the embodiments of the present invention. It should be understood that the described embodiments are only a portion of the embodiments of the present invention, not all of them. Generally, the components of the embodiments of the present invention described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations.

[0032] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0033] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0034] In the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. These are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0035] Furthermore, the terms “first”, “second”, etc. are merely used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0036] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, terms such as "disposed" and "connected" should be understood in a broad sense. For example, "connected" can mean a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can also mean internal communication between two components. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0037] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0038] like Figure 1 As shown, a magnetic fluid dynamic sealing device, the sleeve 2-8 is sleeved on the rotating shaft 8, and the magnetic fluid 2-5 dynamic sealing device includes:

[0039] Base 1; a first end of the base 1 is fixedly mounted on the fixed structure;

[0040] Magnetic fluid seal 2; the magnetic fluid 2-5 of the magnetic fluid seal 2 is arranged around the sleeve 2-8; the first end of the magnetic fluid seal 2 is connected to the second end of the base 1;

[0041] At least two groups of radial support structures are provided; the at least two groups of radial support structures are evenly distributed around the rotating shaft 8; the radial support structures include roller supports 3, the curved roller supports 3 are fixed to the second end of the magnetic fluid seal 2, and the rolling elements of the roller supports 3 are in rolling connection with the rotating shaft 8. In some embodiments, at least three groups of radial support structures are generally selected, and the three groups of radial support structures are evenly distributed around the rotating shaft.

[0042] like Figure 1 and 3 As shown in Figure 4, the roller bearing 3 includes a cavity 3-1, multiple rolling elements 3-3, a retainer 3-4, and a cover plate 3-5. An annular rolling groove is provided within the cavity 3-1, and multiple rolling elements 3-3 are mounted on the retainer 3-4. The multiple rolling elements 3-3 are circulatory and movable within the annular rolling groove. The first side and top of the cavity 3-1 are open, and the cover plate 3-5 is mounted on the top opening of the cavity 3-1. At least one rolling element 3-3 partially protrudes from the side wall of the cavity 3-1 and is in rolling connection with the rotating shaft 8. Specifically, the rolling elements 3-3 are a group of small balls of the same diameter, mounted within the arcuate rolling groove within the cavity 3-1. The retainer 3-4 is a spring sheet with a group of small holes, which is used to maintain a certain gap between the balls as they move within the cavity 3-1. The cover plate 3-5 is used to seal the rolling elements 3-3 and retainer 3-4 within the cavity 3-1. The roller bearing 3 contacts the rotating shaft 8 via the rolling elements 3 - 3 , so the rotating shaft 8 can freely rotate relative to the magnetic fluid seal 2 .

[0043] The first side of the cavity 3 - 1 is an arc surface, which is in accordance with the rotation shaft 8 .

[0044] like Figure 3 and 4 As shown, the radial support structure also includes a wedge-shaped pressure block 4 and a guide rail 3-2. The guide rail 3-2 is fixedly mounted on the second end face of the magnetic fluid seal 2. The cavity 3-1 is slidably mounted on the guide rail 3-2. A first inclined surface is provided on the second side of the cavity 3-1. The first inclined surface and the second inclined surface of the cavity 3-1 are arranged opposite to each other. Correspondingly, a second inclined surface is provided on the first side of the wedge-shaped pressure block 4. The distance between the upper end of the second inclined surface and the rotating shaft 8 is smaller than the distance between the lower end of the second inclined surface and the rotating shaft 8. The first inclined surface and the second inclined surface are wedged together. The wedge-shaped pressure block 4 is connected to the magnetic fluid seal 2 by at least one bolt.

[0045] In some embodiments, a dovetail groove is provided at the bottom of the cavity 3-1, and a dovetail strip is provided on the upper portion of the guide rail 3-2. The dovetail strip can be slidably placed in the dovetail groove. The cavity 3-1 can slide radially along the guide rail 3-2.

[0046] like Figure 4 As shown, the wedge-shaped pressing block 4 is connected to the magnetic fluid seal 2 by two bolts. The purpose of providing the two bolts is to prevent the wedge-shaped pressing block 4 from rotating circumferentially when the bolts rotate.

[0047] like Figure 1 As shown, the base 1 is formed into a bellows-like structure. The bellows structure of the base 1 is made of thin-walled metal. In addition, flange structures are formed at both ends of the base 1, and the upper end flange of the base 1 is axially connected to the sealing seat 2-1 by a plurality of connecting screws 6. A base sealing ring 7 is provided between the upper end flange of the base 1 and the sealing seat 2-1, and the base 1 and the sealing seat 2-1 are sealed by the squeezed base sealing ring 7. Specifically, an annular groove can be provided on the end face of the sealing seat 2-1, and the base sealing ring 7 can be placed in the annular groove. In addition, the lower end flange of the base 1 can also be axially connected to the fixed structure by a plurality of connecting screws 6. The base 1 forms such a special structure that it can bear axial loads while allowing the upper structure supported on the upper end flange to have a small range of radial deflection.

[0048] Because the upper flange of the base 1 can move radially within a small range, during operation, when the rotating shaft 8 deflects under the action of an eccentric load, the magnetic fluid seal 2 is driven to deflect as a whole through the closely contacted arc roller support 3 and the wedge-shaped pressure block 44, thereby ensuring that the relative position between the rotating shaft 8 and the magnetic fluid seal 2 in the radial direction remains unchanged. Therefore, the sealing gap between the sleeve 2-8 mounted on the rotating shaft 8 and the pole shoe 2-4 in the magnetic fluid seal 2 does not fluctuate with the deflection of the rotating shaft 88, and the thickness of the magnetic fluid 2-5 in the sealing gap can also remain stable. Based on this feature, the sealing gap between the sleeve 2-8 and the pole shoe 2-4 can always be kept constant, avoiding the collision between the sleeve 2-8 and the pole shoe 2-4 due to the radial swing of the rotating shaft 8, so the designed sealing gap can be greatly reduced.

[0049] like Figure 2 As shown, the magnetic fluid seal 2 includes a sealing seat 2-1, a permanent magnet 2-3, a pole shoe 2-4, and a sealing cover plate 2-6. The sealing seat 2-1 is formed into a barrel-shaped structure. A through hole is provided at the bottom of the sealing seat 2-1. The sleeve 2-8 is provided through the through hole on the bottom. The permanent magnet 2-3, the pole shoe 2-4, and the sealing cover plate 2-6 are all formed into a ring shape. The permanent magnet 2-3 is installed between the two pole shoes 2-4. The inner rings of the two pole shoes 2-4 are connected to the outer wall of the sleeve 2-8 through the magnetic fluid 2-5. The bottom of the first pole shoe 2-4 is connected to the bottom inside the sealing seat 2-1, and the top of the second pole shoe 2-4 is connected to the bottom of the sealing cover plate 2-6. The first end of the sealing cover plate 2-6 is placed in the sealing seat 2-1, and the second end of the sealing cover plate 2-6 is placed outside the sealing seat 2-1 and fixedly connected to the end of the sealing seat 2-1. The radial support structure is installed on the second end of the sealing cover plate 2-6. When there are multiple permanent magnets 2-3 and pole shoes 2-4, the permanent magnets 2-3 and pole shoes 2-4 are arranged alternately. The magnetic fluid 2-5 is constrained in the sealing gap by the magnetic field force generated by the permanent magnets 2-3 in the gap formed by the pole shoes 2-4 and the shaft sleeve 2-8 to form a sealing effect.

[0050] like Figure 2 As shown, the pole shoe 2-4 is an annular structure with a tooth-shaped protrusion on the inner side, and the magnetic fluid 2-5 is located in the gap between the tooth-shaped protrusion of the pole shoe 2-4 and the shaft sleeve 2-8. Specifically, two annular protrusions are provided on the inner side of the pole shoe 2-4, and a gap is provided between the two annular protrusions.

[0051] like Figure 2 As shown, the magnetic fluid seal 2 also includes a pole piece sealing ring 2-2, which is positioned between the outer ring of the pole piece 2-4 and the inner wall of the sealing seat 2-1. Specifically, an annular groove is provided on the outer ring of the pole piece 2-4, and the pole piece sealing ring 2-2 is positioned within the annular groove. The sealing seat 2-1 and the pole piece 2-4 are sealed by the squeezed pole piece sealing ring 2-2.

[0052] like Figure 2 As shown, the upper end of the sealing cover plate 2-6 is provided with an outwardly protruding flange, and a plurality of cover plate screws 2-7 axially pass through the flange of the sealing cover plate 2-6 and screw into the side wall of the sealing seat 2-1, thereby completing the connection between the sealing cover plate 2-6 and the sealing seat 2-1.

[0053] like Figure 2 As shown, the sleeve 2-8 includes a first inner diameter section and a second inner diameter section; the first inner diameter section of the sleeve 2-8 is arranged near one end thereof, the diameter of the first inner diameter section is larger than that of the second inner diameter section, the expansion sleeve 2-9 and the pressure ring 2-10 are arranged in the first inner diameter section, the pressure ring 2-10 is installed at the step where the first inner diameter section and the second inner diameter section are connected, and the pressure ring 2-10 is axially connected to the sleeve 2-8 through a plurality of pressure ring screws 2-11, and a sleeve sealing ring 2-12 is arranged between the pressure ring 2-10 and the sleeve 2-8; the inner wall of the sleeve 2-8 and the outer wall of the rotating shaft 8 are expansion-connected by the expansion sleeve 2-9.

[0054] like Figure 1 and 2 As shown, the upper end surface of the cover plate is provided with a groove for radial sliding of the roller support 3 and for the up-and-down sliding of the wedge-shaped pressure block 4. The wedge-shaped pressure block 4 is slidably connected to the side wall of the groove relative to one side of its upper inclined surface. This structural design prevents radial displacement of the wedge-shaped pressure block 4, while axial displacement of the wedge-shaped pressure block 4 is achieved by the synchronous rotation of two bolts. Under the pressure of the preload screw 5, the wedge-shaped pressure block 4 slides downward and pushes the cavity 3-1 radially toward and presses the rotating shaft 8 through the wedge-shaped inclined surface. During installation, the pressing force of the arc-shaped roller support 3 on the rotating shaft 8 can be adjusted by adjusting the installation torque of the preload screw 5, thereby ensuring a uniform gap between the rotating shaft 88 and the magnetic fluid seal 2 at all points in the circumferential direction. The preload force also ensures that the rolling elements 3-3 in the arc-shaped roller support 3 always maintain close contact with the rotating shaft 8, thereby achieving precise positioning between the rotating shaft 8 and the magnetic fluid seal 2.

[0055] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A magnetic fluid dynamic sealing device, wherein the sleeve is mounted on the rotating shaft, characterized in that: The magnetic fluid dynamic sealing device includes: Base; a first end of the base is fixedly mounted on the fixed structure; A magnetic fluid seal; the magnetic fluid of the magnetic fluid seal is arranged around the sleeve; the first end of the magnetic fluid seal is connected to the second end of the base; At least two groups of radial support structures; at least two groups of radial support structures are evenly distributed around the rotating shaft; the radial support structure includes a roller support, the roller support includes a cavity, multiple rolling elements, a retaining frame, and a cover plate, an annular rolling groove is provided in the cavity, multiple rolling elements are mounted on the retaining frame, and multiple rolling elements are cyclically movable in the annular rolling groove, the first side and the upper opening of the cavity are provided, the cover plate is mounted on the upper opening of the cavity, at least one rolling element partially protrudes from the side wall of the cavity and is rollingly connected to the rotating shaft; the arc surface roller support is fixed to the second end of the magnetic fluid seal, and The rolling element of the roller support is connected to the rotating shaft in a rolling manner; the radial support structure also includes a wedge-shaped pressure block and a guide rail, the guide rail is fixedly mounted on the second end face of the magnetic fluid seal, the cavity is slidably mounted on the guide rail, a first inclined surface is provided on the second side of the cavity, the first inclined surface and the second inclined surface of the cavity are arranged opposite to each other, and a second inclined surface is correspondingly provided on the first side of the wedge-shaped pressure block, the distance between the upper end of the second inclined surface and the rotating shaft is smaller than the distance between the lower end of the second inclined surface and the rotating shaft, the first inclined surface and the second inclined surface are wedged together, and the wedge-shaped pressure block and the magnetic fluid seal are connected by at least one bolt.

2. A magnetic fluid dynamic sealing device according to claim 1, characterized in that: The first side of the cavity is an arc surface.

3. A magnetic fluid dynamic sealing device according to claim 1, characterized in that: A dovetail groove is provided at the bottom of the cavity, and a dovetail strip is provided on the upper part of the guide rail. The dovetail strip can be slidably placed in the dovetail groove.

4. A magnetic fluid dynamic sealing device according to claim 1, characterized in that: The wedge-shaped pressure block is connected to the magnetic fluid seal through two bolts.

5. A magnetic fluid dynamic sealing device according to claim 1, characterized in that: The base is formed into a bellows-like structure.

6. A magnetic fluid dynamic sealing device according to claim 1, characterized in that: The magnetic fluid seal includes a sealing seat, a permanent magnet, a pole shoe, and a sealing cover plate. The sealing seat is formed into a barrel-shaped structure. A through hole is provided at the bottom of the sealing seat. The shaft sleeve is arranged through the through hole on the bottom. The permanent magnet, the pole shoe, and the sealing cover plate are all formed into a ring shape. The permanent magnet is installed between the two pole shoes. The inner rings of the two pole shoes are connected to the outer wall of the shaft sleeve through the magnetic fluid. The bottom of the first pole shoe is connected to the bottom of the sealing seat, and the top of the second pole shoe is connected to the bottom of the sealing cover plate. The first end of the sealing cover plate is placed in the sealing seat, and the second end of the sealing cover plate is placed outside the sealing seat and fixedly connected to the end of the sealing seat. The radial support structure is installed on the second end of the sealing cover plate.

7. A magnetic fluid dynamic sealing device according to claim 6, characterized in that: The pole shoe is an annular structure with a tooth-shaped protrusion on the inner side, and the magnetic fluid is located in the gap between the tooth-shaped protrusion of the pole shoe and the shaft sleeve.

8. A magnetic fluid dynamic sealing device according to claim 6, characterized in that: The magnetic fluid seal also includes a pole shoe sealing ring, which is arranged between the outer ring of the pole shoe and the inner wall of the sealing seat.

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