CN112728113B

CN112728113B - Magnetic liquid sealing device

Info

Publication number: CN112728113B
Application number: CN202110129491.XA
Authority: CN
Inventors: 李德才; 赵云翔; 杨晟
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2021-01-29
Filing date: 2021-01-29
Publication date: 2022-04-12
Anticipated expiration: 2041-01-29
Also published as: CN112728113A

Abstract

The embodiment of the invention provides a magnetic liquid sealing device and an assembling method thereof. According to the magnetic liquid sealing device provided by the embodiment of the invention, the avoidance groove for avoiding the permanent magnet is arranged on the peripheral wall surface of the cavity, the permanent magnet can be positioned in the avoidance groove and further away from the pole teeth, so that the relative distance between the permanent magnet and the pole teeth can be conveniently adjusted in the assembling process, the magnetic liquid can be uniformly and effectively distributed in the sealing gap, and the magnetic liquid can be prevented from being adsorbed onto the permanent magnet by mistake. The magnetic liquid sealing device provided by the embodiment of the invention has the advantages that the magnetic liquid is uniformly distributed, and the magnetic liquid is not easily adsorbed by the permanent magnet.

Description

Magnetic liquid sealing device

Technical Field

The invention relates to the field of sealing devices, in particular to a magnetic liquid sealing device.

Background

The magnetic liquid sealing device has the advantages of zero leakage, no abrasion, long service life, simple structure and the like, and is used by more and more industries. However, due to the small sealing gap, the response characteristic of the magnetic liquid to the magnetic field, and the like, it is difficult to uniformly and effectively fill the magnetic liquid into the sealing gap to form a stable and ideal magnetic liquid seal. In addition, the magnetic liquid is easily adsorbed by the permanent magnet in the filling process, so that the loss of the magnetic liquid is caused, and the sealing performance is influenced.

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 sealing device which has the advantages that the magnetic liquid is uniformly distributed, and the magnetic liquid is not easily adsorbed by a permanent magnet.

The embodiment of the invention also provides an assembling method of the magnetic liquid sealing device, which can enable the magnetic liquid to be uniformly and effectively distributed in the sealing gap and effectively avoid the magnetic liquid from being adsorbed by the permanent magnet.

The magnetic liquid sealing device according to the embodiment of the invention comprises: a shaft housing defining a chamber; the rotating shaft is rotatably arranged in the cavity; the pole shoe is sleeved on the rotating shaft and positioned in the cavity, a plurality of pole teeth which are distributed along the axial direction of the rotating shaft are formed on the inner circumferential surface of the pole shoe, a tooth groove is formed between every two adjacent pole teeth, and magnetic liquid for sealing is adsorbed on the tooth top surface of each pole tooth; at least one permanent magnet group, permanent magnet group includes a plurality of permanent magnets, a plurality of permanent magnets are followed the circumference of pivot centers on the pivot sets up, permanent magnet group with the pole shoe cooperation is so that do the pole shoe provides magnetic force, some edges of the week wall face of cavity the radial outside of pivot is extended so that form at least one and dodge the groove, dodge the groove with the permanent magnet is in the radial of pivot is relative, at least some of permanent magnet can be located in dodge the groove so that keep away from the utmost point tooth.

According to the magnetic liquid sealing device provided by the embodiment of the invention, the avoidance groove for avoiding the permanent magnet is arranged on the peripheral wall surface of the cavity, the permanent magnet can be positioned in the avoidance groove and further away from the pole teeth, so that the relative distance between the permanent magnet and the pole teeth can be conveniently adjusted in the assembling process, the magnetic liquid can be uniformly and effectively distributed in the sealing gap, and the magnetic liquid can be prevented from being adsorbed onto the permanent magnet by mistake.

Therefore, the magnetic liquid sealing device provided by the embodiment of the invention has the advantages that the magnetic liquid is uniformly distributed, and the magnetic liquid is not easily adsorbed by the permanent magnet.

In some embodiments, dodge the groove including the annular groove of dodging, the annular groove of dodging with permanent magnet group one-to-one, the annular dodge the groove with rather than corresponding every in the permanent magnet group the permanent magnet is relative in the footpath of pivot, perhaps, be formed with a plurality ofly on the week wall of cavity the groove of dodging, dodge the groove with the permanent magnet one-to-one, just dodge the groove with rather than corresponding the permanent magnet is in the footpath of pivot is relative.

In some embodiments, the permanent magnet groups include a first permanent magnet group, the pole pieces include a first pole piece and a second pole piece, each of the first permanent magnet group and the avoidance slot is located between the first pole piece and the second pole piece in an axial direction of the rotating shaft, a first side of the avoidance slot near the first pole piece is flush with a second side of the first pole piece near the avoidance slot, and a third side of the avoidance slot near the second pole piece is flush with a fourth side of the second pole piece near the avoidance slot.

In some embodiments, the permanent magnet is cylindrical.

In some embodiments, guide protrusions extending in a radial direction of the rotating shaft are formed at both ends of the permanent magnet, guide grooves matched with the guide protrusions are formed on the first side surface and the third side surface of the escape groove, the second side surface of the first pole piece, and the fourth side surface of the second pole piece, and the guide protrusions are matched in the guide grooves.

In some embodiments, guide grooves extending in a radial direction of the rotating shaft are formed at both ends of the permanent magnet, and guide protrusions matched with the guide grooves are formed on the first side surface and the third side surface of the escape groove, the second side surface of the first pole piece, and the fourth side surface of the second pole piece, and the guide protrusions are matched in the guide grooves.

In some embodiments, a limiting protrusion is formed on at least one of the second side of the first pole piece and the fourth side of the second pole piece, and the limiting protrusion can be abutted against the permanent magnet so as to limit the permanent magnet to move inwards.

In some embodiments, the shaft housing includes a first sub-shaft housing and a second sub-shaft housing, the first sub-shaft housing and the second sub-shaft housing being arranged in an axial direction of the rotating shaft and detachably connected to each other, the first pole piece being located in the first sub-shaft housing, and the second pole piece being located in the second sub-shaft housing.

In some embodiments, the magnetic liquid sealing device further includes a flux sleeve, the flux sleeve is disposed on the rotating shaft, a portion of the flux sleeve is fitted in the avoiding groove, and another portion of the flux sleeve extends out of the avoiding groove so as to contact with the pole shoe, the flux sleeve is provided with an accommodating groove having an opening direction the same as that of the avoiding groove, and the permanent magnet is located in the accommodating groove and contacts with the flux sleeve.

According to the assembling method of the magnetic liquid sealing device provided by the embodiment of the invention, the magnetic liquid sealing device is the magnetic liquid sealing device provided by the embodiment of the invention, and the assembling method comprises the following steps: mounting the pole piece and the permanent magnet within the cavity of the shaft housing with at least a portion of the permanent magnet in the avoidance slot; injecting the magnetic liquid into the gullets of the pole pieces; moving the permanent magnet inward so that the permanent magnet is positioned outside the avoidance slot; and the rotating shaft extends into one end of the chamber and extends out of the other end of the chamber, and the magnetic liquid in the tooth grooves is adsorbed to the pole teeth so as to form a magnetic liquid sealing ring by self.

According to the assembling method of the magnetic liquid sealing device, before the magnetic liquid is injected, at least one part of the permanent magnet is positioned in the avoidance groove, so that the distance between the permanent magnet and the pole teeth is longer, the magnetism of the pole teeth is weaker, and the adsorption capacity of the magnetic liquid is not strong, after the magnetic liquid is injected into the tooth grooves of the pole shoes, the permanent magnet is moved to be close to the pole teeth, the magnetism of the pole teeth is enhanced, the rotating shaft is installed, the magnetic field intensity gradient near the pole teeth is increased, and the magnetic liquid in the tooth grooves is adsorbed to the tooth top surfaces and uniformly distributed in the sealing gaps.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

Fig. 1 is a schematic structural diagram of a magnetic fluid sealing device according to an embodiment of the present invention.

Fig. 2 is a schematic view of the permanent magnet of fig. 1.

Fig. 3 is a sectional view a-a of fig. 1.

Fig. 4 is a schematic structural view of a magnetic fluid sealing device according to a fourth embodiment of the present invention.

Reference numerals:

magnetic fluid seal device 100, shaft housing 110; a chamber 111; a peripheral wall surface 1111; an avoidance slot 112; a first sub-shaft housing 113; a second sub-axle housing 114; a rotating shaft 120; a pole piece 130; the pole teeth 131; a magnetic liquid 132; a first pole piece 133; the second guide protrusion 1331; a limit protrusion 1332; a second pole piece 134; a permanent magnet 140; the first guide groove 141; a flux sleeve 150; an accommodation groove 151; a first sidewall 152; a second side wall 153; a connecting bolt 160; a first bearing 171; a second bearing 172; a first seal ring 181; a second seal ring 182; end cap 190.

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.

A magnetic fluid seal apparatus 100 according to an embodiment of the present invention is described below with reference to fig. 1 to 4.

The magnetic fluid seal apparatus 100 includes a shaft housing 110, a rotating shaft 120, a pole piece 130, and at least one permanent magnet set.

The shaft housing 110 defines a chamber 111. The rotation shaft 120 is rotatably disposed in the chamber 111, and the rotation shaft 120 extends into the chamber 111 from one end of the shaft housing 110 and extends from the other end of the shaft housing 110. The pole shoe 130 is sleeved on the rotating shaft 120, a plurality of pole teeth 131 arranged along the axial direction of the rotating shaft 120 are formed on the inner circumferential surface of the pole shoe 130, and a tooth slot is formed between two adjacent pole teeth 131.

A gap is formed between the tooth top surface of each tooth 131 and the circumferential surface of the rotating shaft 120, and a magnetic liquid 132 is adsorbed on the tooth top surface of each tooth 131, and the magnetic liquid 132 is used for sealing. The magnetic liquid 132 can be filled in the gap. It is understood that the magnetic liquid 132 is in contact with both the circumferential surface of the rotating shaft 120 and the tooth top surface of the pole teeth 131, so that the magnetic liquid sealing apparatus 100 has a good sealing effect. A pole piece 130 is located within the chamber 111.

Each permanent magnet group includes a plurality of permanent magnets 140, and the plurality of permanent magnets 140 are spaced around the rotating shaft 120 along the circumferential direction of the rotating shaft 120. The permanent magnet sets cooperate with the pole piece 130 to provide a magnetic force to the pole piece 130. For example, the permanent magnet 140 abuts against the pole piece 130 to provide the pole piece 130 with the magnetic force of the permanent magnet 140, so that the pole teeth 131 on the pole piece 130 have the magnetic force capable of attracting the magnetic liquid 132. It should be noted that the relative distance between the permanent magnet 140 and the pole tooth 131 may affect the magnetic force of the pole tooth 131, and thus the ability of the pole tooth 131 to adsorb the magnetic liquid 132, and the permanent magnet 140 is far from the pole tooth 131, the magnetic force of the pole tooth 131 is reduced, the permanent magnet 140 is close to the pole tooth 131, and the magnetic force of the pole tooth 131 is increased.

A part of the peripheral wall surface 1111 of the chamber 111 extends outward in the radial direction of the rotation shaft 120 to form at least one escape groove 112, the escape groove 112 being opposed to the permanent magnet 140 in the radial direction of the rotation shaft 120. At least a portion of the permanent magnet 140 can be located in the escape slot 112 so as to be distant from the pole teeth 131.

The ability of at least a portion of the permanent magnet 140 to be located in the escape slot 112 means: the permanent magnet 140 may or may not be located in the avoidance slot 112, and the permanent magnet 140 may be located completely in the avoidance slot 112 or only partially in the avoidance slot 112. It is understood that when at least a portion of the permanent magnet 140 is located in the avoiding groove 112, the permanent magnet 140 may be located further to the outside, i.e. the permanent magnet 140 is further away from the rotating shaft 120, compared to the position state that the permanent magnet is not located in the avoiding groove 112 at all, and since the pole teeth 131 are located close to the rotating shaft 120, the permanent magnet 140 is further away from the rotating shaft 120 and also further away from the pole teeth 131. By providing the avoidance slot 112, the permanent magnet 140 can be made to "move away" from the pole teeth 131. It will be appreciated that the provision of the relief groove 112 does not affect that the permanent magnets 140 can provide strong magnetic forces to the teeth 131 in close proximity to the teeth 131.

When the magnetic liquid sealing device 100 in the above embodiment is assembled, the avoiding groove can be used to adjust the relative distance between the permanent magnet 140 and the pole teeth 131 in the installation process, so as to adjust the magnetism of the pole teeth 131, thereby effectively controlling the injected magnetic liquid 132, preventing the magnetic liquid 132 from being unevenly distributed, and preventing the magnetic liquid 132 from being adsorbed on the permanent magnet 140.

Specifically, before magnetic fluid 132 is injected, at least a portion of permanent magnets 140 are positioned in avoidance slot 112 to reduce the ability of teeth 131 to attract magnetic fluid 132, and magnetic fluid 132 is injected onto pole piece 130, where magnetic fluid 132 will tend to be more localized in the tooth slot, i.e., between adjacent teeth 131, due to the weaker magnetic properties of teeth 131. After the magnetic liquid 132 is filled, the permanent magnet 140 is moved inward to be completely separated from the avoiding groove 112. After the rotating shaft 120 is assembled into the chamber 111, the gap between the tooth top surface of the pole tooth 131 and the peripheral surface of the rotating shaft 120 is a sealing gap, the sealing gap is small, and the magnetic field intensity gradient near the tooth top surface of the pole tooth 131 is large, so that the magnetic liquid 132 in the tooth grooves is adsorbed to the tooth top surface of the pole tooth 131 under the action of a magnetic field and is positioned in the sealing gap to form an annular magnetic liquid sealing ring.

The invention also provides an assembling method of the magnetic liquid sealing device, and the magnetic liquid sealing device is the magnetic liquid sealing device 100 provided by the embodiment of the invention. The assembling method comprises the following steps:

step 1: mounting the pole piece 130 and the permanent magnet 140 within the cavity 111 of the shaft housing 110 with at least a portion of the permanent magnet 140 located in the escape slot 112;

step 2: injecting magnetic liquid 132 into the gullets of pole pieces 130;

and step 3: moving the permanent magnet 140 inward so that the permanent magnet 140 is positioned outside the escape slot 112;

and 4, step 4: the rotating shaft 120 is inserted into one end of the chamber 111 and extends out from the other end of the chamber 111, and the magnetic liquid 132 in the tooth socket is attracted to the pole teeth 131.

According to the assembling method of the magnetic liquid sealing device, before the magnetic liquid is injected, at least one part of the permanent magnet is positioned in the avoidance groove, so that the distance between the permanent magnet and the pole teeth is longer, the magnetism of the pole teeth is weaker, and the adsorption capacity of the magnetic liquid is not strong, after the magnetic liquid is injected into the tooth grooves of the pole shoes, the permanent magnet is moved to be close to the pole teeth, the magnetism of the pole teeth is enhanced, the pole teeth are installed into the rotating shaft, and the magnetic liquid in the tooth grooves is adsorbed to the tooth top surfaces and uniformly distributed in the sealing gaps.

For convenience of description, the following describes the technical solution of the present embodiment by taking the axial direction of the rotating shaft 120 as the left-right direction as an example, and the left-right direction is shown by an arrow in fig. 1.

A magnetic liquid sealing apparatus 100 according to an embodiment of the present invention is described below with reference to the drawings.

The first embodiment is as follows:

as shown in fig. 1, the magnetic liquid sealing apparatus 100 in the present embodiment includes a shaft housing 110, a rotating shaft 120, a first pole piece 133, a second pole piece 134, and a permanent magnet group (a first permanent magnet group). The first permanent magnet group includes a plurality of permanent magnets 140, and the plurality of permanent magnets 140 are arranged around the rotating shaft 120 along the circumferential direction of the rotating shaft 120. In this embodiment, the permanent magnet 140 is cylindrical and has the same axial direction as the rotating shaft 120. It is understood that in other embodiments, the permanent magnet 140 may have other columnar structures.

The first pole piece 133 and the second pole piece 134 are both sleeved on the rotating shaft 120, and the outer peripheral surfaces thereof are both connected with the peripheral wall surface 1111 of the chamber 111 so as to be connected with the shaft housing 110. The first permanent magnet group is located between the first pole piece 133 and the second pole piece 134 in the axial direction of the rotating shaft 120, that is, each permanent magnet 140 is located between the first pole piece 133 and the second pole piece 134 in the axial direction of the rotating shaft 120.

In this embodiment, an annular escape groove 111 is provided on the peripheral wall 1111 of the chamber 111, the escape groove 111 is opposite to each permanent magnet 140 in the radial direction of the rotating shaft 120, and the permanent magnet 140 may be located in the escape groove 111. The depth of the avoidance slot 111 in the embodiment shown in fig. 1 is larger than the diameter of the permanent magnet 140, i.e. the permanent magnet 140 may be located completely within the avoidance slot 111.

In other embodiments, when the permanent magnet group includes a plurality of permanent magnet groups, the plurality of permanent magnet groups are arranged in the axial direction of the rotating shaft 120, the annular avoidance groove 111 includes a plurality of avoidance grooves and corresponds to the permanent magnet groups one by one, and the avoidance groove 111 and each permanent magnet 140 in the permanent magnet group corresponding thereto are opposite to each other in the radial direction of the rotating shaft 120.

Specifically, as shown in fig. 1, the permanent magnet 140 has a first end (left end) and a second end (right end) opposite to each other in the axial direction of the rotating shaft 120, and the escape groove 111 has a bottom surface and a first side surface (left side surface) and a second side surface (right side surface) opposite to each other in the axial direction of the rotating shaft 120.

The first pole piece 133 is located on the left side of the escape slot 111 and the second pole piece 134 is located on the right side of the escape slot 112. The left side surface of the escape groove 111 is flush with the right side surface of the first pole piece 133, and the right side surface is flush with the left side surface of the second pole piece 134.

The left end of the permanent magnet 140 abuts against at least one of the left side surface of the avoiding groove 111 and the right side surface of the first pole shoe 133, and the right end of the permanent magnet 140 abuts against at least one of the right side surface of the avoiding groove 111 and the left side surface of the second pole shoe 134.

As an example, when the permanent magnet is completely located in the escape groove 112, the left end of the permanent magnet 140 abuts against the left side surface of the escape groove 111, and the right end abuts against the right side surface of the escape groove 111. When the permanent magnet is not located in the escape slot 112 at all, the left end of the permanent magnet 140 abuts against the right side surface of the first pole piece 133, and the right end abuts against the left side surface of the second pole piece 134. When only a portion of the permanent magnet 140 is located in the escape groove 111, a left end of the permanent magnet 140 abuts each of the left side surface of the escape groove 111 and the right side surface of the first pole shoe 133, and a right end of the permanent magnet 140 abuts each of the right side surface of the escape groove 111 and the left side surface of the second pole shoe 134.

When the magnetic fluid seal device 100 provided in the present embodiment is installed, the first pole piece 133, the second pole piece 134, and the permanent magnets 140 are installed in the chamber 111 of the shaft housing 110, and each permanent magnet 140 is located in the avoidance groove 112. And then the magnetic liquid 132 is injected into the tooth grooves of the first and

second pole pieces

133 and 134. Each permanent magnet 140 is moved inwards so as to move the permanent magnet 140 out of the avoiding groove 112, as the distance between the permanent magnet 140 and the pole teeth 131 is reduced, the magnetic property of the pole teeth 131 is gradually improved under the action of the magnetic field of the permanent magnet 140, the adsorption capacity of the magnetic liquid 132 is also gradually improved, the pole teeth 131 are arranged in the rotating shaft 120, the magnetic liquid 132 in the tooth grooves is adsorbed on the pole teeth 131 and is positioned in the seal gap with strong magnetic field intensity, the magnetic liquid 132 is uniformly distributed on the pole teeth 131, and the magnetic liquid 132 is prevented from being adsorbed on the permanent magnet 140 by mistake.

The magnetic liquid 132 may be injected directly or through holes formed in the shaft housing 110 and the pole shoe 130, and a person skilled in the art may select the injection method as needed, which is not limited herein.

Alternatively, after the rotating shaft 120 is installed in the assembling process, the rotating shaft 120 may be slowly rotated at a rotation speed of 10 rpm, so that the magnetic liquid 132 is more uniformly distributed under the driving of the rotating shaft 120.

Further, in order to make the installation of the permanent magnet 140 more accurate and convenient in the assembling process, a first guide protrusion or a first guide groove extending in the radial direction of the rotating shaft 120 may be provided on both end surfaces of the permanent magnet 140 for guiding, and correspondingly, a second guide groove matching with the first guide protrusion or a second guide protrusion matching with the first guide groove may be provided on the side wall surface of the escape groove 112, and the first pole piece 133 and the second pole piece 134. The first guide projection may be fitted in the second guide groove. The second guide projection may be fitted in the first guide groove. This arrangement can better ensure that the movement of the permanent magnet 140 during the assembly process is a movement in the radial direction of the rotation shaft 120,

furthermore, in order to further improve the assembling accuracy of the permanent magnet 140, the right side surface of the first pole shoe 133 and the left side surface of the second pole shoe 134 are provided with limiting protrusions, after the permanent magnet 140 moves inwards for a certain distance, the inner side surface of the permanent magnet 140 abuts against the limiting protrusions, and the limiting protrusions limit the permanent magnet 140 to prevent the permanent magnet 140 from continuously moving inwards, thereby better helping to find the installation position of the permanent magnet 140.

As an example, as shown in fig. 2 and 3, a first guide groove 141 is provided on a left side surface of the permanent magnet 140, and a second guide protrusion 1331 that is matched with the first guide groove 141 is provided on a left side surface of the escape groove 112 and a right side surface of the first pole piece 133. A limiting protrusion 1332 is further provided on the right side surface of the first pole piece 133. The first guide groove 141 and the second guide protrusion 1331 both extend in a radial direction of the rotation shaft 120, and the second guide protrusion 1331 can be fitted in the first guide groove 141 to guide the movement of the permanent magnet 140. The limiting protrusion 1332 is perpendicular to the second guide protrusion 1331 to limit the innermost mounting position of the permanent magnet 140.

Further, as shown in fig. 1, the magnetic fluid sealing device 100 further includes a first bearing 171, a second bearing 172, a sealing cavity (not shown), an end cap 190, a first sealing ring 181, and a second sealing ring 182.

The first pole piece 171, the second pole piece 172, and the first permanent magnet group are located between the first bearing 171 and the second bearing 172 in the axial direction of the rotating shaft 120. A sealed chamber is connected to one end of the shaft housing 110, the sealed chamber defining a sealed cavity for containing a sealed liquid. An end cap 190 is attached to the other end of the shaft housing 110 and cooperates with the shaft housing 110 to define a chamber 111.

The first seal ring 181 is located between the outer peripheral surface of the first pole piece 133 and the peripheral wall surface of the shaft chamber 111, and the second seal ring 182 is located between the outer peripheral surface of the second pole piece 134 and the peripheral wall surface of the shaft chamber 111. The first and second seal rings 181 and 182 improve the sealing between the outer circumferential surfaces of the first and

second pole pieces

133 and 134 and the circumferential wall surface of the shaft chamber 111. Alternatively, the first and second sealing rings 181 and 182 may be one of O-rings, V-rings, and U-rings.

Alternatively, the material of the first and

second pole pieces

133 and 134 is made of electrical pure iron. The material of the shaft housing 120 and the end cap 190 is non-magnetic material, such as stainless steel. The material of the permanent magnet 140 may be neodymium iron boron.

Example two:

the structure of the magnetic liquid sealing device in this embodiment is substantially the same as that in the first embodiment, and will not be described herein. The difference is that a plurality of avoiding grooves 112 are formed on the peripheral wall 1111, the plurality of avoiding grooves 112 correspond to the plurality of permanent magnets 140 in the first permanent magnet group one by one, the avoiding grooves 112 are opposite to the corresponding permanent magnets 140 in the radial direction of the rotating shaft 120, that is, at least a part of the permanent magnets 140 can be located in the corresponding avoiding grooves 112. It is understood that the plurality of avoiding grooves 112 are arranged on the circumferential wall 1111 around the circumference of the rotation shaft 120. Alternatively, in other embodiments, a plurality of avoiding grooves 112 are formed on the peripheral wall 1111 and arranged around the circumference of the rotating shaft 120, and each avoiding groove 112 corresponds to a plurality of permanent magnets 140.

It should be noted that, in other embodiments, when the magnetic liquid sealing device 100 includes a plurality of permanent magnet groups, the plurality of permanent magnet groups includes a plurality of permanent magnets 140, and the peripheral wall 1111 is formed with a plurality of avoiding grooves 112, the number of the avoiding grooves 112 is the same as the number of the permanent magnets 140 and corresponds to the permanent magnets 140 one by one.

Example three:

the structure of the magnetic liquid sealing device in this embodiment is substantially the same as that in the first embodiment, and will not be described herein. In contrast, as shown in fig. 4, the shaft housing 110 in the present embodiment includes a first sub-shaft housing 113 and a second sub-shaft housing 114. The first sub-shaft housing 113 and the second sub-shaft housing 114 are arranged in the axial direction of the rotation shaft 120 and detachably connected to each other. The first sub-shaft housing 113 and the second sub-shaft housing 114 together define a chamber 111 and an escape slot 112. Optionally, the first sub-shaft housing 113 and the second sub-shaft housing 114 are connected by a connecting bolt 160.

The first pole piece 133 is located within the sub-chamber formed by the first sub-shaft housing 113 and the second pole piece 134 is located within the sub-chamber formed by the second sub-shaft housing 114. The permanent magnet 140 has a left end extending into the first sub-spindle housing 113 and a right end extending into the second sub-spindle housing 114.

By providing the first and second

sub-shaft housings

113 and 114, movement and installation of the permanent magnet 140 is facilitated. Specifically, tightening the connecting bolt 160 causes the first and second

sub-shaft housings

113 and 114 to clamp the permanent magnet 140. After the magnetic liquid 132 is injected, the coupling bolt 160 is loosened so that the permanent magnet 140 is changed from the clamped state to the movable state, and after the permanent magnet 140 is moved to a proper position, the coupling bolt 160 is tightened so that the first and second

sub-shaft housings

113 and 114 clamp the permanent magnet 140 again. Therefore, the magnetic fluid sealing device 100 provided with the first sub-shaft housing 113 and the second sub-shaft housing 114 has the advantages of convenient installation and reasonable structure.

Example four:

the structure of the magnetic liquid sealing device 100 in this embodiment is basically the same as that in the third embodiment, and will not be described herein. In contrast, as shown in fig. 4, the magnetic fluid sealing apparatus 100 in this embodiment further includes a magnetic conductive sleeve 150. One part of the flux sleeve 150 fits into the avoiding groove 112, and the other part protrudes out of the avoiding groove 112 to contact with the first pole piece 133 and the second pole piece 134.

The flux sleeve 150 is provided with an accommodating groove 151 with an inward opening. It can be understood that the receiving groove 151 is annular, the opening direction of the receiving groove 151 faces the direction of the rotating shaft 120, and the depth of the receiving groove 151 is along the radial direction of the rotating shaft 120. Each permanent magnet 140 is located in the accommodation groove 151, and the permanent magnet 140 is in contact with the flux sleeve 150. Because the flux sleeve 150 is always in contact with each of the permanent magnets 140 and the pole shoe 130, the flux sleeve 150 can better transfer the magnetism of the permanent magnets 140 to the pole shoe 130, and in addition, because each permanent magnet 140 is located in the accommodating groove 151, the arrangement of the flux sleeve 150 can improve the integrity and the integration degree of the magnetic liquid sealing device 100, so that the structure of the magnetic liquid sealing device 100 is more reasonable.

Specifically, the accommodating groove 151 has a first side wall 152 and a second side wall 153 opposite to each other in the axial direction of the rotation shaft 120, and the left end of the permanent magnet 140 abuts against the first side wall 152 and the right end abuts against the second side wall 153. The portion of the flux sleeve 150 located in the avoiding groove 112 is adapted to the avoiding groove 112 to improve the structural rationality of the magnetic fluid seal apparatus 100.

When the magnetic liquid sealing apparatus 100 of the present embodiment is assembled, the permanent magnet 140 can move along the first side wall 152 and the second side wall 153, and it should be noted that the permanent magnet 140 will not detach from the accommodating groove 151 at all times.

The flux sleeve 150 may be clamped by the first sub-shaft housing 113 and the second sub-shaft housing 114 to avoid axial play.

Further, in order to facilitate the positioning and installation of the flux sleeve 150, step structures are formed on the right side surface of the first pole piece 133 and the left side surface of the second pole piece 134, and the inner sides of the portions of the flux sleeve 150 extending out of the avoiding groove 112 are respectively abutted to the step surfaces of the step structures of the first pole piece 133 and the second pole piece 134, so that the flux sleeve 150 is better prevented from moving, and the structural stability is improved.

Alternatively, the flux sleeve 150 may be made of hard magnetic rubber, the permanent magnet 140 and the elastic flux sleeve 150 are in an interference fit, and the elastic flux sleeve 150 may protect the permanent magnet 140 from being damaged due to rigid impact or abrasion during movement.

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 specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; may be mechanically coupled, may be electrically coupled or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

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 present disclosure, the terms "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" and the like mean that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. 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

1. A magnetic fluid seal assembly, comprising:

a shaft housing defining a chamber;

the rotating shaft is rotatably arranged in the cavity;

the pole shoe is sleeved on the rotating shaft and positioned in the cavity, a plurality of pole teeth which are distributed along the axial direction of the rotating shaft are formed on the inner circumferential surface of the pole shoe, a tooth groove is formed between every two adjacent pole teeth, and magnetic liquid for sealing is adsorbed on the tooth top surface of each pole tooth;

at least one permanent magnet group, permanent magnet group includes a plurality of permanent magnets, the permanent magnet is the column, a plurality of permanent magnets are followed the circumference of pivot centers on the pivot sets up, permanent magnet group with the pole shoe cooperation is so that for the pole shoe provides magnetic force, some edges of the week wall face of cavity radially outwards extend so that form at least one dodge the groove of pivot, dodge the groove with the permanent magnet is in the footpath of pivot is relative, at least some of permanent magnet can be located in dodge the groove so that keep away from the utmost point tooth.

2. The magnetic liquid seal device according to claim 1, wherein the avoiding groove includes an annular avoiding groove, the annular avoiding groove corresponds to the permanent magnet groups one to one, the annular avoiding groove is opposed to each of the permanent magnets in the permanent magnet group corresponding thereto in a radial direction of the rotating shaft,

or, be formed with on the week wall of cavity a plurality ofly dodge the groove, dodge the groove with the permanent magnet one-to-one, just dodge the groove with rather than corresponding the permanent magnet is in the footpath of pivot is relative.

3. The magnetic fluid seal apparatus of claim 2, wherein the permanent magnet groups include a first permanent magnet group, the pole shoe includes a first pole shoe and a second pole shoe, each of the first permanent magnet group and the avoidance slot is located between the first pole shoe and the second pole shoe in an axial direction of the shaft, a first side of the avoidance slot near the first pole shoe is flush with a second side of the first pole shoe near the avoidance slot, and a third side of the avoidance slot near the second pole shoe is flush with a fourth side of the second pole shoe near the avoidance slot.

4. The magnetic liquid sealing device according to claim 3, wherein guide protrusions extending in a radial direction of the rotation shaft are formed at both ends of the permanent magnet, guide grooves matched with the guide protrusions are formed on the first and third sides of the escape groove, the second side of the first pole piece, and the fourth side of the second pole piece, and the guide protrusions are fitted in the guide grooves.

5. The magnetic liquid sealing device according to claim 3, wherein guide grooves extending in a radial direction of the rotating shaft are formed at both ends of the permanent magnet, and guide protrusions fitted with the guide grooves are formed on the first and third sides of the escape groove, the second side of the first pole piece, and the fourth side of the second pole piece, and the guide protrusions are fitted in the guide grooves.

6. The magnetic fluid seal apparatus of claim 4 or 5, wherein a limit protrusion is formed on at least one of the second side surface of the first pole piece and the fourth side surface of the second pole piece, the limit protrusion being capable of abutting against the permanent magnet so as to limit inward movement of the permanent magnet.

7. The magnetic fluid seal apparatus of claim 3, wherein said shaft housing comprises a first sub-shaft housing and a second sub-shaft housing, said first sub-shaft housing and said second sub-shaft housing being arranged in an axial direction of said rotating shaft and being detachably connected to each other, said first pole piece being located in said first sub-shaft housing, said second pole piece being located in said second sub-shaft housing.

8. The magnetic liquid sealing device according to claim 1, further comprising a flux sleeve, wherein the flux sleeve is disposed on the rotating shaft, a portion of the flux sleeve is fitted in the avoiding groove, and another portion of the flux sleeve extends out of the avoiding groove so as to contact with the pole shoe, the flux sleeve is provided with an accommodating groove having an opening direction the same as that of the avoiding groove, and the permanent magnet is disposed in the accommodating groove and contacts with the flux sleeve.

9. A method of assembling a magnetic fluid seal device according to any of claims 1 to 8, the method comprising the steps of:

mounting the pole piece and the permanent magnet within the cavity of the shaft housing with at least a portion of the permanent magnet in the avoidance slot;

injecting the magnetic liquid into the gullets of the pole pieces;

moving the permanent magnet inward so that the permanent magnet is positioned outside the avoidance slot;

and the rotating shaft extends into one end of the chamber and extends out of the other end of the chamber, and the magnetic liquid in the tooth grooves is adsorbed to the pole teeth so as to form a magnetic liquid sealing ring by self.