CN113847435A - Magnetic liquid seal and dynamic pressure bearing combined sealing device - Google Patents

Abstract

The invention discloses a magnetic liquid sealing and dynamic pressure bearing combined sealing device which comprises a shell, a rotating shaft, a pole shoe unit and a bearing, wherein a cavity is arranged in the shell, at least part of the rotating shaft is rotatably matched in the cavity, the pole shoe unit is sleeved on the rotating shaft, the inner peripheral wall of the pole shoe unit is sealed with the magnetic liquid on the outer peripheral wall of the rotating shaft through the magnetic liquid, the bearing is arranged in the cavity and sleeved on the rotating shaft, the bearing is positioned on at least one side of the pole shoe unit in the length direction of the rotating shaft, and the magnetic liquid is filled between the inner peripheral surface of the bearing and the outer peripheral surface of the rotating shaft. The magnetic liquid seal and dynamic pressure bearing combined sealing device provided by the embodiment of the invention has the advantages of good sealing performance, long service life and the like.

Description

Magnetic liquid seal and dynamic pressure bearing combined sealing device

Technical Field

The invention relates to the technical field of mechanical engineering sealing, in particular to a magnetic liquid sealing and dynamic pressure bearing combined sealing device.

Background

The magnetic liquid sealing device is widely used due to the advantages of zero leakage, low friction and long service life, and under some working conditions, for example, when the rotating shaft rotates at high speed or the shaft diameter of the rotating shaft is large, the radial runout of the rotating shaft is large due to limited installation precision and machining precision, so that the service life and the reliability of the magnetic liquid sealing are influenced.

In the related art, the magnetic liquid sealing device is provided with a rolling bearing or a sliding bearing, when the rolling bearing is adopted, a larger radial clearance exists between the rolling bearing and a rotating shaft, the rotating shaft is more prone to radial run-out, a sealing gap between a pole shoe of the magnetic liquid sealing device and the rotating shaft is not easy to guarantee, and then the pole teeth in the pole shoe are easy to abrade and fatigue with the rotating shaft, so that the reliability of magnetic liquid sealing is seriously reduced, the service life of the magnetic liquid sealing device is also shortened, when the sliding bearing is adopted, the sealing gap cannot be guaranteed due to the characteristics of the sliding bearing, and accordingly, the run-out of the shaft is increased, and sealing failure is caused.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.

Therefore, the embodiment of the invention provides a magnetic liquid seal and dynamic pressure bearing combined sealing device, which can maintain a sealing gap, and has strong disturbance resistance and good stability. The magnetic fluid seal and hydrodynamic bearing combined sealing device comprises:

the shell is internally provided with a cavity;

a rotating shaft, at least part of which is rotatably matched in the cavity;

the pole shoe unit is sleeved on the rotating shaft, and the inner circumferential wall of the pole shoe unit is sealed with the magnetic liquid on the outer circumferential wall of the rotating shaft through the magnetic liquid;

the bearing is arranged in the cavity and sleeved on the rotating shaft, the bearing is positioned on at least one side of the pole shoe unit in the length direction of the rotating shaft, and magnetic liquid is filled between the inner peripheral surface of the bearing and the outer peripheral surface of the rotating shaft.

The magnetic liquid seal and dynamic pressure bearing combined sealing device provided by the embodiment of the invention has the advantages of good sealing performance, long service life and the like.

In some embodiments, the magnetic fluid seal and hydrodynamic bearing combined sealing device further includes an inner shell, the inner shell is located in the cavity and sleeved on the rotating shaft, a gap is formed between an outer surface of the inner shell and an inner surface of the outer shell, a sealing member is disposed between one end of the inner shell and the outer shell, an elastic member is disposed between the other end of the inner shell and the outer shell, and the bearing is disposed in the inner shell.

In some embodiments, the magnetic fluid seal and hydrodynamic bearing combined sealing device further includes a first permanent magnet disposed in the inner housing, the first permanent magnet is sleeved on an outer circumferential side of the bearing, and an outer circumferential surface of the first permanent magnet is attached to an inner circumferential surface of the inner housing.

In some embodiments, the bearings and the first permanent magnets are both multiple, the multiple bearings are arranged at intervals along the length direction of the rotating shaft, the multiple first permanent magnets are arranged at intervals along the length direction of the rotating shaft, and the bearings and the first permanent magnets are in one-to-one correspondence.

In some embodiments, the bearing is provided with a plurality of grooves on the inner circumferential wall thereof at intervals along the circumferential direction of the bearing.

In some embodiments, each of the grooves has a first recess and a second recess, the first recess and the second recess being arranged in sequence in an axial direction of the bearing, at least a part of the first recess extending in a direction toward the second recess and being provided obliquely downward, and at least a part of the second recess extending in a direction toward the first recess and being provided obliquely downward, in a longitudinal section of the bearing.

In some embodiments, an end of the first recess adjacent the second recess intersects an end of the second recess adjacent the first recess.

In some embodiments, the magnetic fluid seal and hydrodynamic bearing combined sealing device further includes a magnetism isolating ring, the magnetism isolating ring is located between the bearing and the pole shoe unit and is sleeved on the rotating shaft, and an outer circumferential surface of the magnetism isolating ring is attached to an inner circumferential surface of the inner shell.

In some embodiments, the pole shoe unit comprises a first pole shoe, a second pole shoe and a second permanent magnet, the second permanent magnet is clamped and fixed between the first pole shoe and the second pole shoe, magnetic liquid is filled between the inner circumferential wall of the first pole shoe and the outer circumferential wall of the rotating shaft, and magnetic liquid is filled between the inner circumferential wall of the second pole shoe and the outer circumferential wall of the rotating shaft.

In some embodiments, the magnetic fluid seal and hydrodynamic bearing combined sealing device further includes a shaft sleeve, at least a portion of the shaft sleeve is fitted in the inner housing, the shaft sleeve is sleeved on the outer peripheral side of the rotating shaft, and the shaft sleeve is in rotation-stopping connection with the rotating shaft.

Drawings

Fig. 1 is a schematic view of a combined sealing device of a magnetic fluid seal and a dynamic pressure bearing according to an embodiment of the present invention.

Fig. 2 is a schematic longitudinal cross-sectional view of an embodiment of the first aspect of the bearing of fig. 1.

Fig. 3 is a schematic longitudinal cross-sectional view of an embodiment of a second aspect of the bearing of fig. 1.

Reference numerals:

a rotating shaft 1;

a housing 2; a housing body 21; a housing end cap 22; a housing bolt 23;

an inner shell 3; an inner shell body 31; an inner shell end cap 32; inner shell bolts 33; a seal 34; an elastic member 35;

a bearing 4; a groove 41; the first recess 411; a second recess 412;

a first permanent magnet 5; a magnetism isolating ring 6;

a first pole piece 71; a second pole piece 72; a second permanent magnet 73; a first seal ring 710; a second seal ring 720;

and a sleeve 8.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

As shown in fig. 1 to 3, the magnetic fluid seal and hydrodynamic bearing combined seal device according to an embodiment of the present invention includes a rotating shaft 1, a housing 2, a pole shoe unit, and a bearing 4.

The hollow cavity is arranged in the shell 2, at least part of the rotating shaft 1 is rotatably matched in the hollow cavity, the pole shoe unit is sleeved on the rotating shaft 1, the inner peripheral wall of the pole shoe unit is sealed with the magnetic liquid on the outer peripheral wall of the rotating shaft 1 through the magnetic liquid, the bearing 4 is arranged in the hollow cavity and sleeved on the rotating shaft 1, the bearing 4 is located on at least one side of the pole shoe unit in the length direction of the rotating shaft 1, and the magnetic liquid is filled between the inner peripheral surface of the bearing 4 and the outer peripheral surface of the rotating shaft 1.

In order to make the technical solution of the present application more easily understood, the technical solution of the present application is further described with the extending direction of the rotating shaft 1 coinciding with the left-right direction, wherein the left-right direction is as shown in fig. 1.

The rotating shaft 1 extends along the left-right direction and penetrates through the shell 2, the pole shoe unit and the bearing 4 are both located in a cavity of the shell 2, the pole shoe unit and the bearing 4 are both sleeved on the rotating shaft 1, and magnetic liquid is filled between the inner peripheral wall of the pole shoe unit and the outer peripheral wall of the rotating shaft 1. Magnetic liquid is filled between the inner peripheral surface of the bearing 4 and the outer peripheral surface of the rotating shaft 1, and the rotating shaft 1 can rotate relative to the bearing 4.

Alternatively, the bearing 4 is a dynamic pressure bearing.

The arrangement of the bearings 4 is various, and the bearings 4 can be arranged on the left side of the pole shoe unit, or the bearings 4 can be arranged on the right side of the pole shoe unit, or the bearings 4 can be arranged on the left side and the right side of the pole shoe unit.

When the magnetic liquid seal and dynamic pressure bearing combined sealing device works, the bearing 4 does not move, the rotating shaft 1 is in the rotating process, the magnetic liquid filled between the bearing 4 and the rotating shaft 1 can generate hydrodynamic pressure under the driving of the rotating shaft 1, so that the magnetic liquid between the bearing 4 and the rotating shaft 1 has certain bearing capacity and fluid film rigidity, and the magnetic liquid between the bearing 4 and the rotating shaft 1 is in an O-shaped film shape and surrounds the rotating shaft 1, so that the connecting part of the rotating shaft 1 and the bearing 4 can be sealed, and the magnetic liquid can serve as a lubricant. When the rotating shaft 1 runs stably, the gravity of the rotating shaft 1 and the bearing capacity of the magnetic liquid maintain a balanced state, at this time, on the cross section of the matching part of the rotating shaft 1 and the bearing 4, the section circle of the rotating shaft 1 and the section circle of the bearing 4 are not concentric, in other words, when the rotating shaft 1 runs stably, the central axis of the rotating shaft 1 and the central axis of the bearing 4 are not coincident, and the gap between the rotating shaft 1 and the bearing 4 is locally small and locally large. At this time, the rotary shaft 1 is in a normal working position.

When the radial swing appears in the pivot 1, the pivot 1 breaks away from normal operating position, can appear two kinds of condition this moment, one kind is that the clearance between pivot 1 and the bearing 4 becomes even gradually, and the regional grow gradually that the clearance is little, and the bearing capacity of this regional magnetic liquid weakens, and gravity is greater than the bearing capacity, and gravity can make the pivot 1 get back to normal operating position. The other is that the rotating shaft 1 gradually approaches the bearing 4, namely the region with small gap is gradually reduced, at this time, the magnetic liquid in the region is squeezed, the bearing body of the magnetic liquid is increased, and the bearing force of the magnetic liquid pushes the rotating shaft 1 to return to the normal working position.

When the shaft 1 oscillates radially, the gap between the pole shoe unit and the shaft 1 is also affected. When the bearing 4 adjusts the gap between the bearing 4 and the rotating shaft 1, the bearing 4 can transmit the motion mode of the bearing to the pole shoe unit, so that the gap change between the pole shoe unit and the rotating shaft 1 is consistent with the gap change between the bearing 4 and the rotating shaft 1, the gap between the pole shoe unit and the rotating shaft 1 is maintained in a stable range, and the sealing performance between the pole shoe unit and the rotating shaft 1 is ensured.

When the magnetic liquid sealing and dynamic pressure bearing combined sealing device does not work, the magnetic liquid between the bearing 4 and the rotating shaft 1 is always in the original position due to the magnetic attraction of the pole shoe unit, the magnetic liquid cannot be reduced, the bearing capacity of the magnetic liquid cannot be reduced, and the stable operation of the magnetic liquid sealing and dynamic pressure bearing combined sealing device can be guaranteed.

According to the combined sealing device of the magnetic liquid seal and the dynamic pressure bearing, disclosed by the embodiment of the invention, the magnetic liquid is filled in the gap between the bearing 4 and the rotating shaft 1, so that the magnetic liquid can generate hydrodynamic pressure when the rotating shaft 1 rotates, and when the rotating shaft 1 swings in the radial direction, the magnetic liquid can adjust the gap between the bearing 4 and the rotating shaft 1, so that the gap between the pole shoe unit and the rotating shaft 1 is adjusted, and the pole shoe unit and the rotating shaft 1 can always keep good sealing performance. And the clearance between the pole shoe unit and the rotating shaft 1 can be always kept in a stable range, the pole shoe unit cannot be damaged due to the impact of the rotating shaft 1, and the reliability and the service life of the magnetic liquid sealing and hydrodynamic bearing combined sealing device are improved.

Therefore, the magnetic liquid seal and dynamic pressure bearing combined sealing device provided by the embodiment of the invention has the advantages of strong disturbance resistance, high reliability, long service life and the like.

The magnetic liquid has various types, such as ester-based magnetic liquid, engine oil-based magnetic liquid, fluoroether oil-based magnetic liquid, and the like, and can be selected according to actual working conditions.

In some embodiments, the magnetic fluid seal and dynamic pressure bearing combined sealing device according to embodiments of the present invention further includes an inner shell 3, the inner shell 3 is located in the cavity and is sleeved on the rotating shaft 1, a gap is provided between an outer surface of the inner shell 3 and an inner surface of the outer shell 2, a sealing member 34 is disposed between one end of the inner shell 3 and the outer shell 2, an elastic member 35 is disposed between the other end of the inner shell 3 and the outer shell 2, and the bearing 4 is disposed in the inner shell 3.

As shown in fig. 1, an inner casing 3 is further provided inside the outer casing 2, the rotating shaft 1 passes through the inner casing 3, and the bearing 4 and the pole shoe unit are both provided inside the inner casing 3. When the magnetic liquid seal and dynamic pressure bearing combined sealing device works, when the rotating shaft 1 swings in the radial direction, the gap between the bearing 4 and the rotating shaft 1 is reduced, the pressure of the magnetic liquid is increased after the magnetic liquid is extruded, the bearing 4 is pushed to move, the bearing 4 can drive the inner shell 3 to move together, and the inner shell 3 further drives the pole shoe unit to move together, so that the pole shoe unit and the rotating shaft 1 keep relative movement, the sealing gap and the sealing performance between the pole shoe unit and the rotating shaft 1 are maintained, and the reliability and the stability of sealing are enhanced.

When radial swing or axial float appear in pivot 1, inner shell 3 can relative movement in outer shell 2, can not transmit pivot 1 motion for outer shell 2, from this, avoids outer shell 2 vibrations to appear. Specifically, be equipped with the sealing washer between the left end of inner shell 3 and shell 2, be equipped with the spring between the right-hand member of inner shell 3 and the shell 2, when the combined sealing device of magnetic fluid seal and dynamic pressure bearing was at the axial float, the elasticity of spring can hinder the combined sealing device axial float of magnetic fluid seal and dynamic pressure bearing, the sealing washer adopts rubber materials to make, the sealing washer still has sufficient compressive capacity when the combined sealing device axial float of magnetic fluid seal and dynamic pressure bearing, thereby guarantee that inner shell 3 can remove along the left and right directions in shell 2. When the magnetic liquid seal and dynamic pressure bearing combined sealing device swings in the radial direction, the spring can swing in the radial direction of the rotating shaft 1, and the sealing ring can slightly move in the radial direction, so that the inner shell 3 can move in the radial direction of the rotating shaft 1 in the outer shell 2.

Alternatively, the elastic member 35 may be a spring or a bellows. When the elastic member 35 is a spring, a spring groove for fixing the spring is provided on one of the inner case 3 and the outer case 2. When the elastic member 35 is a corrugated tube, one end of the corrugated tube is fixedly connected to the inner shell 3, and the other end of the corrugated tube is fixedly connected to the outer shell 2.

Optionally, the seal 34 is one or more. A seal groove for fixing the seal 34 is provided on one of the inner casing 3 and the outer casing 2.

It should be noted that the inner shell 3 includes an inner shell body 31 and an inner shell cover 32, the inner shell body 31 and the inner shell cover 32 are detachably connected, for example, the inner shell body 31 and the inner shell cover 32 are connected by an inner shell bolt 33, thereby facilitating the assembly and disassembly of the bearing 4 and the pole piece unit in the inner shell 3.

In some embodiments, the magnetic fluid seal and hydrodynamic bearing combined sealing device according to an embodiment of the present invention further includes a first permanent magnet 5, the first permanent magnet 5 is disposed in the inner housing 3, the first permanent magnet 5 is sleeved on an outer peripheral side of the bearing 4, and an outer peripheral surface of the first permanent magnet 5 is attached to an inner peripheral surface of the inner housing 3.

As shown in fig. 1, a first permanent magnet 5 is further provided on the outer peripheral side of the bearing 4, the inner peripheral surface of the first permanent magnet 5 is bonded to the outer peripheral surface of the bearing 4, and the outer peripheral surface of the first permanent magnet 5 is bonded to the inner peripheral surface of the inner casing 3. From this, first permanent magnet 5 not only can transmit the motion of bearing 4 for inner shell 3 to drive the pole shoe unit and move together, in order to maintain stable sealed effect, first permanent magnet 5 can firmly adsorb the magnetic fluid between bearing 4 and pivot 1 on the inner peripheral surface of bearing 4 moreover, thereby reduces and even avoids the magnetic fluid to run off, and then guarantees that bearing 4 and pivot 1 can even running.

In some embodiments, the number of the bearings 4 and the number of the first permanent magnets 5 are multiple, the multiple bearings 4 are arranged at intervals along the length direction of the rotating shaft 1, the multiple first permanent magnets 5 are arranged at intervals along the length direction of the rotating shaft 1, and the bearings 4 and the first permanent magnets 5 correspond to each other one by one.

As shown in fig. 1, the number of the bearings 4 corresponds to that of the first permanent magnets 5, one first permanent magnet 5 is arranged on the outer peripheral side of each bearing 4, and magnetic liquid is filled between the inner peripheral surface of each bearing 4 and the rotating shaft 1. The plurality of bearings 4 are arranged at intervals in the left-right direction.

The number of the bearings 4 can be selected according to actual working conditions, for example, the number of the bearings is 1, 2, 3, 4, 5, etc.

Optionally, bearings 4 and first permanent magnets 5 are arranged on the left and right sides of the pole shoe unit, so that the rotating shaft 1 can run more smoothly and smoothly.

In some embodiments, the inner circumferential wall of the bearing 4 is provided with a plurality of grooves 41 arranged at intervals along the circumferential direction of the bearing 4.

As shown in fig. 2 and 3, a plurality of grooves 41 are provided on the inner circumferential wall of the bearing 4, the plurality of grooves 41 being arranged at intervals along the circumferential direction of the bearing 4. Therefore, when the magnetic liquid seal and dynamic pressure bearing combined sealing device works, relative rotation is generated between the rotating shaft 1 and the bearing 4, the groove 41 can rub with the magnetic liquid, and the magnetic liquid is helped to form a fluid dynamic pressure effect, so that the magnetic liquid has bearing capacity and rigidity, and the relative position between the bearing 4 and the rotating shaft 1 can be adjusted in time. When the magnetic liquid seal and hydrodynamic bearing combined sealing device does not work, the magnetic liquid is gathered in the groove 41 under the magnetic attraction of the first permanent magnet 5, and the groove 41 can limit the flow of the magnetic fluid, so that the loss of the magnetic liquid is avoided.

In some embodiments, each groove 41 has a first recess 411 and a second recess 412, the first recess 411 and the second recess 412 are sequentially arranged in the axial direction (the left-right direction shown in fig. 1) of the bearing 4, and in a longitudinal section of the bearing 4 (as shown in fig. 2), at least a part of the first recess 411 extends in a direction toward the second recess 412 and is provided obliquely downward, and at least a part of the second recess 412 extends in a direction toward the first recess 411 and is provided obliquely downward.

For convenience of description, the up-down direction in fig. 2 is referred to as the up-down direction of the bearing 4, and the left-right direction in fig. 2 is referred to as the left-right direction of the bearing 4.

As shown in fig. 2 and 3, the first recess 411 is at the left end of the bearing 4, and the second recess 412 is at the right end of the bearing 4. The first concave portion 411 is provided obliquely rightward and downward, and the second concave portion 412 is provided obliquely leftward and downward.

The first recess 411 and the second recess 412 are "arrow-shaped" as a whole, and the direction of the arrow is designed according to the rotation direction of the rotating shaft 1, and the direction of the arrow is consistent with the rotation direction of the rotating shaft 1, in other words, when the bearing 4 and the rotating shaft 1 are viewed from the left side of the bearing 4, the rotating shaft 1 rotates clockwise when in operation, and the direction of the arrow is clockwise, or when the rotating shaft 1 rotates counterclockwise when in operation, and the direction of the arrow is counterclockwise. Thereby, the hydrodynamic effect of the magnetic liquid between the bearing 4 and the rotating shaft 1 is facilitated.

It should be noted that, since the groove 41 is arranged along the circumferential direction of the bearing 4, fig. 2 shows only a part of the groove 41, and the first recess 411 and the second recess 412 are inclined downward when viewing the groove 41 from the perspective of fig. 2, and the first recess 411 and the second recess 412 are inclined upward when viewing the groove 41 at an angle opposite to that of fig. 2.

Alternatively, the first recess 411 and the second recess 412 are symmetrically arranged. Therefore, the magnetic liquid can generate dynamic pressure with equal magnitude at the first concave part 411 and the second concave part 412, and the stress at the left end and the right end of the bearing 4 is balanced, so that the magnetic liquid is prevented from being thrown out from between the bearing 4 and the rotating shaft 1 due to uneven stress, and the operation stability of the magnetic liquid sealing and dynamic pressure bearing combined sealing device is enhanced.

In some embodiments, an end of the first recess 411 adjacent the second recess 412 intersects an end of the second recess 412 adjacent the first recess 411.

As shown in fig. 3, the right end of the first recess 411 and the left end of the second recess 412 communicate. From this, magnetic fluid can flow between the left end and the right-hand member of bearing 4, and magnetic fluid's distribution that can be even is at the both ends of bearing 4, and the film thickness that magnetic fluid formed is also more even to help improving magnetic fluid seal and dynamic pressure bearing combination formula sealing device's operating stability.

In some embodiments, the depth of the first recess 411 and the depth of the second recess 412 are in the order of micrometers.

The depth of the first recess 411 is a dimension of the first recess 411 in a direction perpendicular to the inner circumferential surface of the bearing 4. The depth of the second recess 412 is a dimension of the second recess 412 in a direction perpendicular to the inner circumferential surface of the bearing 4.

Optionally, the depth of the first recess 411 is 2-20 microns. E.g., 2 microns, 2-10 microns, 15 microns, 20 microns, etc.

Optionally, the depth of the first recess 411 is 2-20 microns. E.g., 2 microns, 2-12 microns, 18 microns, 20 microns, etc.

In some embodiments, the magnetic fluid seal and hydrodynamic bearing combined sealing device according to embodiments of the present invention further includes a magnetism isolating ring 6, the magnetism isolating ring 6 is located between the bearing 4 and the pole shoe unit and is sleeved on the rotating shaft 1, and an outer circumferential surface of the magnetism isolating ring 6 is attached to an inner circumferential surface of the inner shell 3.

As shown in fig. 1, a magnetism isolating ring 6 is disposed between the bearing 4 and the pole shoe unit, an outer circumferential surface of the magnetism isolating ring 6 is attached to an inner circumferential surface of the inner casing 3, and a space is provided between the inner circumferential surface of the magnetism isolating ring 6 and the rotating shaft 1.

It should be noted that, in this embodiment, the bearings 4 and the first permanent magnets 5 are disposed on both sides of the pole shoe unit, so the number of the magnetism isolating rings 6 is two.

Therefore, the magnetism isolating ring 6 can separate the magnetic force of the first permanent magnet 5 from the magnetic force in the pole shoe unit, and mutual interference between the magnetic force and the magnetic force in the pole shoe unit is avoided, so that the magnetic liquid between the bearing 4 and the rotating shaft 1 can be stably kept in the original position, the magnetic liquid in the pole shoe unit can be stably kept in the original position, and the reliability of the magnetic liquid sealing and dynamic pressure bearing combined sealing device is further enhanced.

In some embodiments, the pole piece unit includes a first pole piece 71, a second pole piece 72, and a second permanent magnet 73, the second permanent magnet 73 is clamped and fixed between the first pole piece 71 and the second pole piece 72, a magnetic liquid is filled between an inner circumferential wall of the first pole piece 71 and an outer circumferential wall of the rotating shaft 1, and a magnetic liquid is filled between an inner circumferential wall of the second pole piece 72 and an outer circumferential wall of the rotating shaft 1.

As shown in fig. 1, each pole shoe unit is provided with a first pole shoe 71 and a second pole shoe 72 which are arranged at intervals in the left-right direction, a second permanent magnet 73 is arranged between the first pole shoe 71 and the second pole shoe 72, and two sides of the second permanent magnet 73 are fitted with the first pole shoe 71 and the second pole shoe 72. The polarity of the second permanent magnet 73 is arranged along the left-right direction, optionally, the left side of the second permanent magnet 73 is an N pole, and the right side is an S pole, or the left side of the second permanent magnet 73 is an S pole, and the right side of the second permanent magnet 73 is an N pole.

When the left side of the second permanent magnet 73 is an S pole and the right side is an N pole, the magnetic induction line starts from the N pole of the second permanent magnet 73, passes through the second pole shoe 72, passes through the rotating shaft 1, passes through the first pole shoe 71, and finally returns to the S pole of the second permanent magnet 73, so as to form a complete magnetic loop.

A plurality of annular grooves 41 arranged at intervals can be arranged on the inner circumferential walls of the first pole piece 71 and the second pole piece 72, a pole tooth is formed between any two adjacent annular grooves 41, magnetic induction lines are gathered on the pole tooth, magnetic liquid can be adsorbed on the pole tooth, and when the rotating shaft 1 rotates, the magnetic liquid can form an O-shaped sealing ring, so that the sealing effect is achieved. When the shaft 1 stops, the magnetic liquid returns to the pole teeth.

In the present embodiment, there are only 1 pole shoe unit. It will be appreciated that in other embodiments, there may be a plurality of pole shoe units, and the connection points of two adjacent pole shoe units may share one pole shoe. When a plurality of pole shoe units are arranged, the polarities of the two second permanent magnets 73 arranged on the two sides of the shared pole shoe are opposite, so that the directions of the magnetic loops of the two adjacent pole shoe units are kept consistent when the magnetic loops pass through the shared pole shoe, and the disorder of the magnetic field is avoided.

It is understood that the number of the second permanent magnets 73 in each pole shoe unit is not unique, for example, in other embodiments, in order to enhance the sealing effect, a plurality of closely connected second permanent magnets 73 may be provided in one pole shoe unit, and the polarity arrangement direction of two adjacent second permanent magnets 73 is the same, so that the plurality of second permanent magnets 73 may be attracted together in the left-right direction.

In some embodiments, the outer peripheral wall of the first pole piece 71 is provided with a first sealing ring groove, the first sealing ring groove extends along the circumferential direction of the first pole piece 71, the first sealing ring groove is internally fitted with a first sealing ring 710, the outer peripheral wall of the second pole piece 72 is provided with a second sealing ring groove, the second sealing ring groove extends along the circumferential direction of the second pole piece 72, and the second sealing ring groove is internally fitted with a second sealing ring 720.

As shown in fig. 1, a first sealing ring groove extending along the circumferential direction of the first pole piece 71 is formed in the outer circumferential wall of the first pole piece 71, and a first sealing ring 710 is installed in the first sealing ring groove. A second sealing ring groove extending along the circumferential direction of the second pole piece 72 is formed in the outer circumferential wall of the second pole piece 72, and a second sealing ring 720 is installed in the second sealing ring groove. Thereby, the sealing performance between the pole shoe unit and the inner casing 3 is improved.

It will be appreciated that in other embodiments, the first and second sealing ring grooves may also be provided on the inner circumferential wall of the inner casing 3.

In some embodiments, the inner circumferential surface of the first pole piece 71 and the inner circumferential surface of the second pole piece 72 are each provided with teeth having a diameter greater than the diameter of the bearing 4. Therefore, when the rotating shaft 1 is static, the outer peripheral surface of the rotating shaft 1 is in contact with the inner peripheral surface of the bearing 4 at the moment, and the inner peripheral surface of the pole tooth and the outer peripheral surface of the rotating shaft 1 are arranged at intervals, so that the rotating shaft 1 is prevented from being in contact with the pole tooth, and the pole tooth is protected. In the related art, when the magnetic fluid seal device is installed, since the gap between the pole teeth and the rotating shaft 1 is small, the pole teeth are easily damaged when the rotating shaft 1 is installed.

In some embodiments, the magnetic fluid seal and hydrodynamic bearing combined sealing device according to embodiments of the present invention further includes a shaft sleeve 8, at least a portion of the shaft sleeve 8 is fitted in the inner casing 3, and the shaft sleeve 8 is disposed on an outer peripheral side of the rotating shaft 1 and is rotatable with the rotating shaft 1.

As shown in fig. 1, the shaft sleeve 8 is sleeved on the rotating shaft 1, a part of the shaft sleeve 8 is located in the inner housing 3, and the shaft sleeve 8 can rotate along with the rotating shaft 1. Therefore, when the pole shoe unit is installed, the shaft sleeve 8 and the pole shoe unit are integrated, and then the rotating shaft 1 is installed in the shaft sleeve 8, so that the pole shoe unit can be prevented from being damaged due to the fact that the rotating shaft 1 touches pole teeth.

Optionally, the shaft sleeve 8 is connected to the rotating shaft 1 in a sealing manner, for example, a plurality of sealing rings are arranged between the shaft sleeve 8 and the rotating shaft 1 at intervals, so as to enhance the sealing effect.

In some embodiments, the housing 2 includes a housing body 21 and a housing end cap 22. The shell body 21 and the shell end cover 22 are detachably connected. For example, the housing body 21 and the housing cover 22 are connected by the housing bolts 23. Thus, the parts in the housing 2 can be easily detached.

Optionally, the shaft sleeve 8, the bearing 4, the first pole shoe 71 and the second pole shoe 72 are made of magnetic conductive materials, and the outer shell 2, the inner shell 3 and the magnetism isolating ring 6 are made of non-magnetic conductive materials.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specifically defined otherwise.

In the present invention, unless otherwise specifically stated or limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly and can be, for example, fixedly connected, detachably connected, or integrated, mechanically connected, electrically connected or communicable with each other, directly connected, indirectly connected through an intermediate medium, connected internally to two elements, or in an interaction relationship between two elements, unless otherwise specifically stated or limited. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer 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, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims (10)

1. The utility model provides a magnetic fluid seals and combined sealing device of dynamic pressure bearing which characterized in that includes:

the shell is internally provided with a cavity;

a rotating shaft, at least part of which is rotatably matched in the cavity;

the pole shoe unit is sleeved on the rotating shaft, and the inner circumferential wall of the pole shoe unit is sealed with the magnetic liquid on the outer circumferential wall of the rotating shaft through the magnetic liquid;

the bearing is arranged in the cavity and sleeved on the rotating shaft, the bearing is positioned on at least one side of the pole shoe unit in the length direction of the rotating shaft, and magnetic liquid is filled between the inner peripheral surface of the bearing and the outer peripheral surface of the rotating shaft.

2. The combined sealing device for magnetic fluid seal and dynamic pressure bearing according to claim 1, further comprising an inner housing, wherein the inner housing is located in the cavity and sleeved on the rotating shaft, a gap is provided between the outer surface of the inner housing and the inner surface of the outer housing, a sealing member is provided between one end of the inner housing and the outer housing, an elastic member is provided between the other end of the inner housing and the outer housing, and the bearing is provided in the inner housing.

3. The combined sealing device for magnetic fluid seal and dynamic pressure bearing according to claim 2, further comprising a first permanent magnet disposed in the inner housing, the first permanent magnet being fitted around an outer peripheral side of the bearing, an outer peripheral surface of the first permanent magnet being in close contact with an inner peripheral surface of the inner housing.

4. The combined sealing device for magnetic fluid seal and hydrodynamic bearing of claim 3, wherein the bearing and the first permanent magnet are both plural, the plural bearings are arranged at intervals along the length direction of the rotating shaft, the plural first permanent magnets are arranged at intervals along the length direction of the rotating shaft, and the bearing and the first permanent magnets correspond to each other one by one.

5. The combined seal device for magnetic fluid seal and hydrodynamic bearing of claim 4, wherein the inner peripheral wall of said bearing is provided with a plurality of grooves spaced along the circumference of said bearing.

6. The combined sealing device for a magnetic liquid seal and a dynamic pressure bearing according to claim 5, wherein each of said grooves has a first recess and a second recess which are arranged in this order in the axial direction of said bearing, at least a part of said first recess is provided so as to extend in a direction toward said second recess and be inclined downward, and at least a part of said second recess is provided so as to extend in a direction toward said first recess and be inclined downward, in a longitudinal section of said bearing.

7. The combined magnetic fluid seal and dynamic pressure bearing seal device according to claim 6, wherein an end of said first recess adjacent to said second recess intersects an end of said second recess adjacent to said first recess.

8. The combined sealing device for magnetic fluid seal and dynamic pressure bearing as claimed in any one of claims 2 to 7, further comprising a magnetism isolating ring, wherein the magnetism isolating ring is located between the bearing and the pole shoe unit and is sleeved on the rotating shaft, and the outer circumferential surface of the magnetism isolating ring is attached to the inner circumferential surface of the inner housing.

9. The combined sealing device for magnetic liquid seal and dynamic pressure bearing according to claim 8, wherein the pole shoe unit comprises a first pole shoe, a second pole shoe and a second permanent magnet, the second permanent magnet is clamped and fixed between the first pole shoe and the second pole shoe, magnetic liquid is filled between the inner circumferential wall of the first pole shoe and the outer circumferential wall of the rotating shaft, and magnetic liquid is filled between the inner circumferential wall of the second pole shoe and the outer circumferential wall of the rotating shaft.

10. The combined sealing device for magnetic fluid seal and dynamic pressure bearing according to claim 9, further comprising a shaft sleeve, wherein at least a portion of the shaft sleeve is fitted in the inner housing, the shaft sleeve is fitted around the outer peripheral side of the rotating shaft, and the shaft sleeve is connected to the rotating shaft in a rotation stop manner.

Images