阅读说明：本技术 一种嵌入型套筒式磁性液体密封装置 (Embedded sleeve type magnetic liquid sealing device ) 是由 刘泽生 李德才 于 2021-09-29 设计创作，主要内容包括：嵌入型套筒式磁性液体密封装置,属于机械工程密封领域。本发明解决了磁性液体密封装置在高速旋转、转轴偏心的工况下,密封装置耐压性能失效的问题。该装置由非导磁轴、外壳、左极靴、套筒、右极靴、外极靴、隔磁环、永磁体等组成。嵌入型套筒缩短了装置轴向尺寸,增强密封间隙的磁场；左、右极靴与嵌入型套筒内端和外端的密封间隙互相限制,减小了偏心的影响；左极靴的右端和右极靴的左端沿径向间隔设置两个轴向极齿,套筒两端设置一个轴向极齿,极齿交错分布形成迷宫密封；套筒和左右极靴加工出斜面,当转速增大,内端斜面补充中间迷宫密封磁性液体,外端斜面极齿限制磁性液体流失,当转速下降,磁性液体将恢复到原位置,增强了装置在高速工况的密封性能。(An embedded sleeve type magnetic liquid sealing device belongs to the field of mechanical engineering sealing. The invention solves the problem that the pressure resistance of the magnetic liquid sealing device fails under the working conditions of high-speed rotation and eccentric rotating shaft. The device comprises a non-magnetic conduction shaft, a shell, a left pole shoe, a sleeve, a right pole shoe, an outer pole shoe, a magnetism isolating ring, a permanent magnet and the like. The embedded sleeve shortens the axial size of the device and enhances the magnetic field of the sealing gap; the left and right pole shoes and the sealing gaps at the inner end and the outer end of the embedded sleeve are mutually limited, so that the influence of eccentricity is reduced; two axial pole teeth are arranged at the right end of the left pole shoe and the left end of the right pole shoe at intervals along the radial direction, two axial pole teeth are arranged at two ends of the sleeve, and the pole teeth are distributed in a staggered manner to form labyrinth seal; the sleeve and the left and right pole shoes are processed with inclined planes, when the rotating speed is increased, the inner inclined plane supplements the middle labyrinth seal magnetic liquid, the outer inclined plane pole teeth limit the loss of the magnetic liquid, when the rotating speed is reduced, the magnetic liquid can be restored to the original position, and the sealing performance of the device under the high-speed working condition is enhanced.)

1. An embedding type sleeve formula magnetic fluid sealing device which characterized in that: the sealing device includes: the magnetic bearing comprises a shaft (1), a shell (2), a left bearing (3), a left magnetism isolating ring (4), a left sealing ring (5), a left pole shoe (11), a left permanent magnet (6), a sleeve (12), an outer pole shoe (7), a right permanent magnet (8), a sealing ring (13), magnetic liquid (14), a right pole shoe (15), a right sealing ring (9), a right magnetism isolating ring (10), a right bearing (16) and an end cover (17);

the left bearing (3), the shaft (1), the left magnetism isolating ring (4), the left pole shoe (11) with the sealing ring, the left permanent magnet (6), the pole shoe sleeve (12), the outer pole shoe (7), the right permanent magnet (8), the right pole shoe (15) with the sealing ring and the right bearing (16) are sequentially arranged in the shell (2); the left pole shoe (11) and the right pole shoe (15) form labyrinth seal with the left end face and the right end face of the sleeve (12) and form seal with the inner end and the outer end inclined plane of the sleeve (12); a seal is formed between the outer pole shoe (7) and the outer circular surface of the sleeve (12); injecting sufficient magnetic liquid (14) into the device, positioning the right side of the outer ring of the right bearing (16) through an end cover (17), and connecting the end cover (17) with the shell (2) through threads;

the left sealing ring (5) is arranged in a groove on the outer circular surface of the left pole shoe to form a left pole shoe (11) with a sealing ring, the left pole shoe (11) is arranged on the inner wall of the shell, a gap is reserved between the inner circular surface of the left pole shoe and the sleeve, the left end surface of the left pole shoe (11) is connected with the right end surface of the left magnetism isolating ring (4), and the left end surface of the outer circle of the left pole shoe (11) is positioned by the magnetism isolating ring and connected with the left permanent magnet (6);

the sealing ring (13) is arranged in a groove on the inner circular surface of the sleeve to form a sleeve (12) with the sealing ring, the sleeve (12) is arranged on the shaft (1), and the left end surface is positioned for a shaft shoulder; the outer end inclined plane of the sleeve (12) is provided with pole teeth, and a sealing gap is reserved between the pole teeth and the outer end inclined plane of the left pole shoe (11); the left end face and the right end face of the sleeve (12) are provided with pole teeth, the pole teeth are axially installed in a pole tooth space of the left pole shoe, and a sealing gap is reserved between the pole teeth and the right end face of the left pole shoe (11) to form labyrinth seal; the inner end of the sleeve (12) is a smooth inclined surface, a sealing gap is formed between the inner end of the sleeve and the pole teeth of the inclined surface of the inner end of the left pole shoe (11), and magnetic liquid is injected into the sealing gap for sealing;

the right sealing ring (9) is arranged in a groove on the outer circular surface of the right pole shoe to form a right pole shoe (15) with a sealing ring, the right pole shoe (15) is arranged on the inner wall of the shell, a gap is reserved between the inner circular surface of the right pole shoe and the sleeve (12), and the left end surface of the right pole shoe (15) is connected with the left end surface of the right permanent magnet (8) and is positioned by the right permanent magnet (8); a sealing gap is reserved between the outer end smooth inclined plane of the right pole shoe (15) and the pole teeth of the outer end inclined plane of the sleeve (12); the left end face of the right pole shoe (15) is provided with spaced pole teeth, the pole teeth are axially inserted into the pole teeth on the right end face of the sleeve, and a gap is reserved between the pole teeth and the right end face of the sleeve to form labyrinth seal; the inner end inclined plane of the right pole shoe (15) is provided with pole teeth to form a sealing gap with the inner end inclined plane of the sleeve (12), and magnetic liquid (14) is injected into the sealing gap for sealing;

the permanent magnet is arranged in the shell (2), the left permanent magnet (6) is positioned between the left pole shoe (11) and the outer pole shoe (7), the right permanent magnet (8) is positioned between the outer pole shoe (7) and the right pole shoe (15), and the inner circular surface of the permanent magnet keeps a distance from the sleeve;

the outer pole shoe (7) is arranged on the inner wall of the shell (2), the left end and the right end of the outer pole shoe (7) are respectively connected with the left permanent magnet (6) and the right permanent magnet (8), the sleeve (12) and the outer pole shoe (7) correspond to each other, a sealing gap is formed between the outer circular surface of the sleeve (12) and the pole teeth of the outer pole shoe (7), and magnetic liquid (14) is injected into the sealing gap for sealing.

2. The insertion-type sleeve-type magnetic liquid seal device according to claim 1, wherein:

the left pole shoe (11) is made of a magnetic conductive material, an inclined plane is machined at the upper right of the inner end, the inclined angle of the inclined plane is 30 degrees, pole teeth are machined on the inclined plane, the direction of the pole teeth is vertical to the inclined plane, and the number of the pole teeth is 2-5; a flat inclined plane is processed at the right lower part of the outer end, and the inclination angle of the inclined plane is 30 degrees; two pole teeth are arranged on the right end face at intervals along the radial direction, the distance is 3-5mm, and the direction of the pole teeth is vertical to the right end face;

the right pole shoe (15) is made of a magnetic conductive material, an inclined plane is machined at the upper left of the inner end, the inclined angle of the inclined plane is 30 degrees, pole teeth are machined on the inclined plane, the direction of the pole teeth is vertical to the inclined plane, and the number of the pole teeth is 2-5; a flat inclined plane is processed at the upper left of the outer end, and the inclination angle of the inclined plane is 30 degrees; two pole teeth are arranged on the left end face at intervals along the radial direction, the distance is 3-5mm, and the direction of the pole teeth is vertical to the right end face;

the outer end of the sleeve (12) is provided with a bevel which has an inclination angle of 30 degrees, the number of the bevel is 2-5, and the bevel plays roles in forming magnetic liquid seal and limiting magnetic liquid loss; a flat inclined plane is processed at the inner end, the inclination angle is 30 degrees, the inclined plane can supplement the intermediate magnetic liquid at a high speed of the rotating shaft, and the magnetic liquid can be automatically recovered to the original position at a low speed; a pole tooth is processed on the left end face and the right end face of the sleeve (12), and the direction of the pole tooth is vertical to the right end face; the sleeve (12) is used for connecting a rotating shaft, an inner hole is in interference fit with the rotating shaft and is positioned through the shaft (1) and the right bearing (16);

the inner end inclined plane pole teeth of the left pole shoe (11) and the right pole shoe (15) and the inner end inclined plane of the sleeve (12) form a sealing gap, and the size of the gap is 0.1-0.5 mm; the outer end inclined plane of the left pole shoe (11), the outer end inclined plane of the right pole shoe (15) and the outer end inclined plane of the sleeve (12) form a sealing gap, and the size of the gap is 0.1-0.5 mm; the pole teeth on the right end face of the left pole shoe (11) and the left end face of the right pole shoe (15) and the pole teeth on the left end and the right end of the sleeve (12) are distributed in a staggered mode to form radial labyrinth seals, magnetic liquid is injected into axial gaps among the pole teeth, and the size of the seal gaps is 0.1-0.5 mm.

3. The insertion-type sleeve-type magnetic liquid seal device according to claim 1, wherein:

the outer pole shoe (7) is arranged in the shell (2), the sleeve (12) and the outer pole shoe (7) correspond to each other, and a sealing gap is reserved between the outer circular surface of the sleeve (12) and the pole teeth of the outer pole shoe (7); the polarity of left side permanent magnet (6) and right permanent magnet (8) opposite, the left end face of left side permanent magnet (6) is the N utmost point, the right-hand member face is the S utmost point, the left end of right side permanent magnet (8) is the S utmost point, the right-hand member face is the N utmost point, left side magnetic circuit is from left permanent magnet (6) N utmost point, through left pole shoe (11), sleeve (12), outer pole shoe (7) get back to the permanent magnet S utmost point, form left side closed loop, right side magnetic circuit is sent out from right permanent magnet (8) N utmost point, through right pole shoe (15), sleeve (12), outer pole shoe (7) get back to the permanent magnet S utmost point, form right side closed loop.

4. The insertion-type sleeve-type magnetic liquid seal device according to claim 1, wherein:

the left bearing (3) is arranged on the left side of the left magnetism isolating ring (4) and is installed in the shell (2), and the left side of the left bearing (3) is positioned through the shell (2); the right bearing (16) is arranged on the right side of the right magnetism isolating ring (10), the inner ring of the bearing is positioned through the sleeve (12), and the outer ring of the bearing is positioned through the right magnetism isolating ring (10) and the end cover (17).

Technical Field

The invention belongs to the field of mechanical engineering sealing, and relates to an embedded sleeve type magnetic liquid sealing device which is suitable for high-speed rotary sealing.

Background

Magnetic liquid sealing is a new technology which is rapidly developed in recent years, and has the advantages of tight sealing, immeasurable leakage rate, long service life, high reliability, no pollution, small viscous friction, capability of bearing high rotating speed and the like, and is widely applied to various industries. In practical application, due to the influence of factors such as assembly error and vibration, the rotating shaft is eccentric relative to the sealing device, and meanwhile, the pressure resistance of the sealing device is reduced due to the loss of magnetic liquid caused by centrifugal force caused by high-speed rotation of the shaft, so that the improvement of the pressure resistance of the sealing device under different working conditions is a hot problem in current research. One of the methods for improving the pressure resistance of the magnetic liquid seal is to improve the magnetic liquid seal structure, such as the seal device described in the comparison patents (publication numbers CN 110748647 a and CN 109505984 a), and although the seal device described in the above documents has improved sealing performance relative to the common magnetic liquid, the seal device does not compromise the influence of the eccentricity of the rotating shaft and the centrifugal force on the pressure resistance of the magnetic liquid seal.

Disclosure of Invention

The invention aims to solve the technical problem that the existing magnetic liquid sealing device is influenced by factors such as assembly error, vibration and the like, a rotating shaft is eccentric relative to the sealing device, and the pressure resistance of the sealing device is reduced. While taking into account the problem that the high speed rotation of the shaft causes loss of magnetic liquid due to centrifugal forces. Thus, an insert type sleeve type magnetic liquid seal device is provided.

The technical scheme of the invention is as follows:

an insert-type sleeve-type magnetic liquid seal device, the structure comprising: the magnetic bearing comprises a shaft (1), a shell (2), a left bearing (3), a left magnetic isolation ring (4), a left sealing ring (5), a left pole shoe (11), a left permanent magnet (6), a sleeve (12), an outer pole shoe (7), a right permanent magnet (8), a sealing ring (13), magnetic liquid (14), a right pole shoe (15), a right sealing ring (9), a right magnetic isolation ring (10), a right bearing (16) and an end cover (17).

The left sealing ring is arranged in a groove on the outer circular surface of the left pole shoe to form the left pole shoe with the sealing ring; the right sealing ring is arranged in a groove on the outer circular surface of the right pole shoe to form the right pole shoe with the sealing ring; the sleeve is sleeved on the shaft, the left pole shoe and the right pole shoe are arranged in the shell, and the outer circular surfaces of the left pole shoe and the right pole shoe are in contact with the inner wall of the shell; a left permanent magnet is arranged between the left pole shoe and the outer pole shoe, and a right permanent magnet is arranged between the right pole shoe and the outer pole shoe; the left bearing, the left magnetism isolating ring, the left pole shoe with the shaft provided with the sealing ring, the left permanent magnet, the inner pole shoe, the outer pole shoe, the right permanent magnet, the right pole shoe with the sealing ring, the right bearing and the end cover are sequentially arranged in the shell; the left pole shoe with the sealing ring, the right pole shoe with the sealing ring and the sleeve form a seal; the device is filled with a sufficient amount of magnetic liquid and positioned by an end cap which is in threaded connection with the housing.

The left pole shoe (11) is made of a magnetic conductive material, an inclined plane is machined at the upper right of the inner end, the inclined angle of the inclined plane is 30 degrees, pole teeth are machined on the inclined plane, the direction of the pole teeth is vertical to the inclined plane, and the number of the pole teeth is 2-5; a flat inclined plane is processed at the right lower part of the outer end, and the inclination angle of the inclined plane is 30 degrees; two pole teeth are arranged on the right end face at intervals along the radial direction, the distance is 3-5mm, and the direction of the pole teeth is vertical to the right end face.

The right pole shoe (15) is made of a magnetic conductive material, an inclined plane is machined at the upper left of the inner end, the inclined angle of the inclined plane is 30 degrees, pole teeth are machined on the inclined plane, the direction of the pole teeth is vertical to the inclined plane, and the number of the pole teeth is 2-5; a flat inclined plane is processed at the upper left of the outer end, and the inclination angle of the inclined plane is 30 degrees; the left end face is provided with two pole teeth at intervals along the radial direction, the distance is 3-5mm, and the direction of the pole teeth is vertical to the right end face.

The outer end of the sleeve (12) is provided with a bevel which is processed with pole teeth, the inclination angle of the bevel is 30 degrees, and the number of the pole teeth is 2-5; the inner end is processed with a smooth inclined plane, the inclined plane with the inclination angle of 30 degrees plays a role in supplementing the intermediate magnetic liquid when the rotating shaft is at a high speed, and the magnetic liquid automatically restores to the original position when the rotating shaft is at a low speed; a pole tooth is processed on the left end face and the right end face of the sleeve (12), and the direction of the pole tooth is vertical to the right end face.

The inner end inclined plane pole teeth of the left pole shoe (11) and the right pole shoe (15) and the inner end inclined plane of the sleeve (12) form a sealing gap, and the size of the gap is 0.1-0.5 mm; the outer end inclined plane of the left pole shoe (11), the outer end inclined plane of the right pole shoe (15) and the outer end inclined plane of the sleeve (12) form a sealing gap, and the size of the gap is 0.1-0.5 mm; the pole teeth on the right end face of the left pole shoe (11) and the left end face of the right pole shoe (15) and the pole teeth on the left end and the right end of the sleeve (12) are distributed in a staggered mode to form radial labyrinth seals, magnetic liquid is injected into axial gaps among the pole teeth, and the size of the seal gaps is 0.1-0.5 mm.

Compared with the prior art, the invention has the following effects: 1. the embedded sleeve is designed, so that the axial size of the device is shortened, and the magnetic field of a sealing gap is enhanced by adopting the non-magnetic-conductive shaft. 2. When the rotating shaft is eccentric, radial sealing gaps between the left and right pole shoes and the inner end and the outer end of the sleeve are mutually limited, the formed maximum sealing gap is in staggered distribution, the influence of radial gap change caused by the eccentricity of the rotating shaft on the sealing pressure resistance is reduced 3, and the middle pole teeth of the sleeve and the pole shoes are radially staggered to form labyrinth seal, so that the loss of magnetic liquid caused by centrifugal force is reduced. 4. The sleeve and the left and right pole shoes are processed into an inclined annular surface, under the high-speed working condition, when the rotating speed is increased, the magnetic liquid supplements the middle labyrinth seal along the inner end inclined surface, the loss of the magnetic liquid is limited by the pole teeth on the outer end inclined surface, and when the rotating speed is reduced, the magnetic liquid is recovered to the original position along the inclined surface, so that the sealing performance of the device under the high-speed working condition is enhanced.

Drawings

FIG. 1 is a view showing a structure of an insertion type sleeve type magnetic liquid seal apparatus;

in fig. 1: the magnetic bearing comprises a shaft (1), a shell (2), a left bearing (3), a left magnetic isolation ring (4), a left sealing ring (5), a left pole shoe (11), a left permanent magnet (6), a sleeve (12), an outer pole shoe (7), a right permanent magnet (8), a sealing ring (13), magnetic liquid (14), a right pole shoe (15), a right sealing ring (9), a right magnetic isolation ring (10), a right bearing (16) and an end cover (17).

Detailed Description

The invention is further illustrated by the following detailed description of the embodiments:

an insert-type sleeve-type magnetic liquid seal device as shown in fig. 1, comprising: the magnetic bearing comprises a shaft (1), a shell (2), a left bearing (3), a left magnetism isolating ring (4), a left sealing ring (5), a left pole shoe (11), a left permanent magnet (6), a sleeve (12), an outer pole shoe (7), a right permanent magnet (8), a sealing ring (13), magnetic liquid (14), a right pole shoe (15), a right sealing ring (9), a right magnetism isolating ring (10), a right bearing (16) and an end cover (17);

the magnetic bearing comprises a left bearing (3), a shaft (1), a left magnetism isolating ring (4), a left pole shoe (11) with a sealing ring, a left permanent magnet (6), a pole shoe sleeve (12), an outer pole shoe (7), a right permanent magnet (8), a right pole shoe (15) with a sealing ring and a right bearing (16), wherein the left pole shoe (11) and the right pole shoe (15) are sequentially arranged in a shell (2), a labyrinth seal is formed by the left end face and the right end face of the sleeve (12) and the inner end face and the outer end inclined face of the sleeve (12), a seal is formed between the outer pole shoe (7) and the outer circular face of the sleeve (12), sufficient magnetic liquid (14) is injected into the device, the right side of the outer ring of the right bearing (16) is positioned (17) through an end cover, and the end cover (17) is connected with the shell (2) through threads;

the left sealing ring (5) is arranged in a groove on the outer circular surface of the left pole shoe to form a left pole shoe (11) with a sealing ring, the left pole shoe (11) is arranged on the inner wall of the shell, a gap is reserved between the inner circular surface of the left pole shoe and the sleeve, the left end surface of the left pole shoe (11) is connected with the right end surface of the left magnetism isolating ring (4), and the left end surface of the outer circle of the left pole shoe (11) is positioned by the magnetism isolating ring and connected with the left permanent magnet (6);

the sealing ring (13) is arranged in a groove on the inner circle surface of the sleeve to form a sleeve (12) with the sealing ring, the sleeve (12) is arranged on the shaft (1), and the left end surface is positioned for a shaft shoulder. The outer end inclined plane of the sleeve (12) is provided with pole teeth, and a sealing gap is reserved between the pole teeth and the outer end inclined plane of the left pole shoe (11); the left end face and the right end face of the sleeve (12) are provided with pole teeth, the pole teeth are axially installed in a pole tooth space of the left pole shoe, and a sealing gap is reserved between the pole teeth and the right end face of the left pole shoe (11) to form labyrinth seal; the inner end of the sleeve (12) is a smooth inclined surface, a sealing gap is formed between the inner end of the sleeve and the pole teeth of the inclined surface of the inner end of the left pole shoe (11), and magnetic liquid is injected into the sealing gap for sealing;

the right sealing ring (9) is arranged in a groove on the outer circular surface of the right pole shoe to form the right pole shoe (15) with the sealing ring, the right pole shoe (15) is arranged on the inner wall of the shell, a gap is reserved between the inner circular surface of the right pole shoe and the sleeve (12), the left end surface of the right pole shoe (15) is connected with the left end surface of the right permanent magnet (8), and the right pole shoe is positioned through the right permanent magnet (8). A sealing gap is reserved between the outer end smooth inclined plane of the right pole shoe (15) and the pole teeth of the outer end inclined plane of the sleeve (12); the left end face of the right pole shoe (15) is provided with spaced pole teeth, the pole teeth are axially inserted into the pole teeth on the right end face of the sleeve, and a gap is reserved between the pole teeth and the right end face of the sleeve to form labyrinth seal; the inner end inclined plane of the right pole shoe (15) is provided with pole teeth to form a sealing gap with the inner end inclined plane of the sleeve (12), and magnetic liquid (14) is injected into the sealing gap for sealing;

the permanent magnet is arranged in the shell (2), the left permanent magnet (6) is positioned between the left pole shoe (11) and the outer pole shoe (7), the right permanent magnet (8) is positioned between the outer pole shoe (7) and the right pole shoe (15), and a distance is kept between the inner circular surface of the permanent magnet and the sleeve;

the outer pole shoe (7) is arranged on the inner wall of the shell (2), the left end and the right end of the outer pole shoe (7) are respectively connected with the left permanent magnet (6) and the right permanent magnet (8), the sleeve (12) and the outer pole shoe (7) correspond to each other, a sealing gap is formed between the outer circular surface of the sleeve (12) and the pole teeth of the outer pole shoe (7), and magnetic liquid (14) is injected into the sealing gap for sealing.

The left pole shoe (11) is made of a magnetic conductive material, an inclined plane is machined at the upper right of the inner end, the inclined angle of the inclined plane is 30 degrees, pole teeth are machined on the inclined plane, the direction of the pole teeth is vertical to the inclined plane, and the number of the pole teeth is 2-5; a flat inclined plane is processed at the right lower part of the outer end, and the inclination angle of the inclined plane is 30 degrees; two pole teeth are arranged on the right end face at intervals along the radial direction, the distance is 3-5mm, and the direction of the pole teeth is vertical to the right end face.

The right pole shoe (15) is made of a magnetic conductive material, an inclined plane is machined at the upper left of the inner end, the inclined angle of the inclined plane is 30 degrees, pole teeth are machined on the inclined plane, the direction of the pole teeth is vertical to the inclined plane, and the number of the pole teeth is 2-5; a flat inclined plane is processed at the upper left of the outer end, and the inclination angle of the inclined plane is 30 degrees; the left end face is provided with two pole teeth at intervals along the radial direction, the distance is 3-5mm, and the direction of the pole teeth is vertical to the right end face.

The outer end of the sleeve (12) is provided with a bevel which has an inclination angle of 30 degrees, the number of the bevel is 2-5, and the bevel plays roles in forming magnetic liquid seal and limiting magnetic liquid loss; the inner end is processed with a smooth inclined plane, the inclination angle is 30 degrees, the inclined plane plays a role in supplementing the intermediate magnetic liquid when the rotating shaft is at a high speed, and the magnetic liquid automatically restores to the original position when the rotating shaft is at a low speed; a pole tooth is processed to the left and right both ends face of sleeve (12), and the pole tooth direction is perpendicular with the right-hand member face, sleeve (12) are used for the connection of pivot, and the hole adopts interference fit with the pivot, fixes a position through axle (1) and right bearing (16).

The inner end inclined plane pole teeth of the left pole shoe (11) and the right pole shoe (15) and the inner end inclined plane of the sleeve (12) form a sealing gap, and the size of the gap is 0.1-0.5 mm; the outer end inclined plane of the left pole shoe (11), the outer end inclined plane of the right pole shoe (15) and the outer end inclined plane of the sleeve (12) form a sealing gap, and the size of the gap is 0.1-0.5 mm; the pole teeth on the right end face of the left pole shoe (11) and the left end face of the right pole shoe (15) and the pole teeth on the left end and the right end of the sleeve (12) are distributed in a staggered mode to form radial labyrinth seals, magnetic liquid is injected into axial gaps among the pole teeth, and the size of the seal gaps is 0.1-0.5 mm.

The left bearing (3) is arranged on the left side of the left magnetism isolating ring (4) and is installed in the shell (2), and the left side of the left bearing (3) is positioned through the shell (2); the right bearing (16) is arranged on the right side of the right magnetism isolating ring (10), the inner ring of the bearing is positioned through the sleeve (12), and the outer ring of the bearing is positioned through the right magnetism isolating ring (10) and the end cover (17).

Composition of the magnetic circuit: the outer pole shoe (7) is arranged in the shell (2), the sleeve (12) and the outer pole shoe (7) correspond to each other, and a sealing gap is reserved between the outer circular surface of the sleeve (12) and the pole teeth of the outer pole shoe (7); the polarity of left side permanent magnet (6) and right permanent magnet (8) opposite, the left end face of left side permanent magnet (6) is the N utmost point, the right-hand member face is the S utmost point, the left end of right side permanent magnet (8) is the S utmost point, the right-hand member face is the N utmost point, left side magnetic circuit is from left permanent magnet (6) N utmost point, through left pole shoe (11), sleeve (12), outer pole shoe (7) get back to the permanent magnet S utmost point, form left side closed loop, right side magnetic circuit is sent out from right permanent magnet (8) N utmost point, through right pole shoe (15), sleeve (12), outer pole shoe (7) get back to the permanent magnet S utmost point, form right side closed loop.

The pole shoe is made of a material with good magnetic conductivity, such as 2Cr 13;

the permanent magnet is made of rubidium, iron and boron;

the shell, the magnetism isolating ring and the shaft are made of non-magnetic materials such as stainless steel 304;

the magnetic liquid is selected from different base carrier liquids according to different use environments and different sealing media.