CN214036891U - Magnetic liquid reciprocating sealing device - Google Patents

Abstract

The utility model discloses a reciprocal sealing device of magnetic fluid, reciprocal sealing device of magnetic fluid includes casing, reciprocating shaft, adds electric installation and magnetic sealing element, the casing has sealed chamber, sealed intracavity packing has magnetic fluid, reciprocating shaft wears to establish on the casing, add electric installation with reciprocating shaft links to each other, add the electric installation be used for to reciprocating shaft lets in axial current in order to produce the radial magnetic field that weakens from inside to outside of reciprocating shaft, magnetic sealing element is located sealed intracavity, the magnetic sealing element cover is established reciprocating shaft is last, magnetic sealing element's inner peripheral surface with have sealed clearance between reciprocating shaft's the outer peripheral face, magnetic fluid is suitable for being adsorbed under the magnetic force in the sealed clearance. The utility model discloses a reciprocal sealing device of magnetic fluid utilizes magnetic field to supply magnetic fluid in the sealed clearance, can improve sealed effect and life.

Description

Magnetic liquid reciprocating sealing device

Technical Field

The utility model relates to a sealed technical field specifically, relates to a reciprocal sealing device of magnetic fluid.

Background

The magnetic liquid sealing technology has the advantages of zero leakage, no abrasion, long service life, convenient maintenance and the like, and is widely applied to different sealing occasions in the military industry and the civil industry at present.

However, in the magnetic liquid reciprocating sealing device, due to the adhesion phenomenon between the magnetic liquid and the reciprocating shaft, the magnetic liquid at the sealing position is usually carried away by the reciprocating shaft in the moving process, so that the magnetic liquid in the sealing gap is gradually reduced along with the extension of the working time, and the sealing performance and the service life of the magnetic liquid reciprocating sealing device are further influenced.

SUMMERY OF THE UTILITY MODEL

Therefore, the embodiment of the utility model provides a magnetic fluid reciprocating seal device, this magnetic fluid reciprocating seal device utilizes magnetic field to supply magnetic fluid in the sealed clearance, can improve sealed effect and life.

According to the utility model discloses magnetic liquid reciprocating seal device includes: the magnetic liquid separation device comprises a shell, a magnetic liquid separation device and a magnetic liquid separation device, wherein the shell comprises an outer peripheral wall and a cavity surrounded by the outer peripheral wall, the cavity comprises a sealing cavity, and the sealing cavity is filled with magnetic liquid; the reciprocating shaft is movable relative to the shell along the axial direction of the reciprocating shaft, the reciprocating shaft penetrates through the shell along the axial direction of the reciprocating shaft, at least part of the reciprocating shaft is positioned in the cavity, and the axial direction of the reciprocating shaft is generally parallel to the length direction of the peripheral wall; the power-on device is connected with the reciprocating shaft and used for introducing axial current to the reciprocating shaft to generate a magnetic field weakened from inside to outside in the radial direction of the reciprocating shaft; the magnetic sealing element is positioned in the sealing cavity, the magnetic sealing element is sleeved on the reciprocating shaft, the outer peripheral surface of the magnetic sealing element is in contact with the inner peripheral surface of the outer peripheral wall, a sealing gap is formed between the inner peripheral surface of the magnetic sealing element and the outer peripheral surface of the reciprocating shaft, and the magnetic liquid is suitable for being adsorbed in the sealing gap under the action of magnetic force.

According to the utility model discloses magnetic liquid reciprocating seal device, let in axial current to reciprocating shaft through adding the electric installation, make reciprocating shaft produce annular magnetic field, and this magnetic field radially weakens from inside to outside at reciprocating shaft, the magnetic field of reciprocating shaft's outer peripheral face is strongest, magnetic liquid can tend to the stronger department in magnetic field, and then magnetic liquid can attach the outer peripheral face at reciprocating shaft, avoid the magnetic liquid in the seal clearance to outwards run off along with reciprocating shaft's motion, and help the outer magnetic liquid of seal clearance to supply in the seal clearance along with reciprocating shaft, thereby can improve sealed effect and life.

In some embodiments, the magnetic seal comprises: the first pole shoe and the second pole shoe are sleeved on the reciprocating shaft, the sealing gaps are formed between the first pole shoe and the reciprocating shaft and between the second pole shoe and the reciprocating shaft, the first pole shoe and the second pole shoe are arranged at intervals along the axial direction of the reciprocating shaft, and the outer peripheral surface of the first pole shoe and the outer peripheral surface of the second pole shoe are both contacted with the inner peripheral surface of the outer peripheral wall; the permanent magnet is sleeved on the reciprocating shaft, a gap is formed between the permanent magnet and the reciprocating shaft, the outer peripheral surface of the permanent magnet is in contact with the inner peripheral surface of the outer peripheral wall, and the permanent magnet is connected between the first pole shoe and the second pole shoe.

In some embodiments, the permanent magnet, the first pole piece and the second pole piece are all circular rings, the inner diameter of the first pole piece is gradually reduced in a direction close to the second pole piece, and the inner diameter of the second pole piece is gradually reduced in a direction far away from the first pole piece.

In some embodiments, the magnetic fluid reciprocating sealing device further includes a first magnetism isolating ring and a second magnetism isolating ring, the first magnetism isolating ring and the second magnetism isolating ring are disposed in the sealing cavity and are arranged at intervals along the axial direction of the reciprocating shaft, a gap is formed between the first magnetism isolating ring and the reciprocating shaft, the outer peripheral surface of the first magnetism isolating ring and the outer peripheral surface of the second magnetism isolating ring are in contact with the inner peripheral surface of the outer peripheral wall, the end surface of the first magnetism isolating ring adjacent to the second magnetism isolating ring is in contact with the first pole shoe, and the end surface of the second magnetism isolating ring adjacent to the first magnetism isolating ring is in contact with the second pole shoe.

In some embodiments, the magnetic fluid reciprocating sealing device further comprises a first slip ring seal and a second slip ring seal, wherein the inner circumferential surface of the first magnetism isolating ring is provided with a first annular groove, the inner circumferential surface of the second magnetism isolating ring is provided with a second annular groove, the first slip ring seal is fitted in the first annular groove, the second slip ring seal is fitted in the second annular groove, and the inner circumferential surface of the first slip ring seal and the inner circumferential surface of the second slip ring seal are both in contact with the outer circumferential surface of the reciprocating shaft.

In some embodiments, the first slip ring seal comprises a first C-shaped slip ring and a first seal ring, and the second slip ring seal comprises a second C-shaped slip ring and a second seal ring; the first sealing ring is located between the outer peripheral surface of the first C-shaped sliding ring and the bottom wall surface of the first annular groove, the inner peripheral surface of the first C-shaped sliding ring is in contact with the outer peripheral surface of the reciprocating shaft, the second sealing ring is located between the outer peripheral surface of the second C-shaped sliding ring and the bottom wall surface of the second annular groove, and the inner peripheral surface of the second C-shaped sliding ring is in contact with the outer peripheral surface of the reciprocating shaft.

In some embodiments, a side of the first annular groove adjacent to the second pole piece passes through a side of the first magnetism isolating ring adjacent to the second pole piece, and a side of the first C-shaped slip ring adjacent to the second pole piece is in contact with a side of the first pole piece remote from the second pole piece, the first seal ring is in contact with a side of the first pole piece remote from the second pole piece; one side of the second annular groove, which is adjacent to the first pole shoe, penetrates through the side face, which is adjacent to the first pole shoe, of the second magnetism isolating ring, one side, which is adjacent to the first pole shoe, of the second C-shaped sliding ring is in contact with the side face, which is far away from the first pole shoe, of the second pole shoe, and the second sealing ring is in contact with the side face, which is far away from the first pole shoe, of the second pole shoe.

In some embodiments, the magnetic liquid reciprocating sealing device further comprises a third sealing ring and a fourth sealing ring, the outer peripheral surface of the first magnetism isolating ring is provided with a first annular groove, and the outer peripheral surface of the second magnetism isolating ring is provided with a second annular groove; the third sealing ring is matched in the first annular groove, the first sealing ring is in contact with the inner peripheral surface of the outer peripheral wall, the fourth sealing ring is matched in the second annular groove, and the second sealing ring is in contact with the inner peripheral surface of the outer peripheral wall.

In some embodiments, the magnetic liquid reciprocating sealing device further comprises a fifth sealing ring and a sixth sealing ring, the end surface of the first magnetism isolating ring adjacent to the second magnetism isolating ring is provided with a third annular groove, and the end surface of the second magnetism isolating ring adjacent to the first magnetism isolating ring is provided with a fourth annular groove; the fifth sealing ring is matched in the third annular groove, the fifth sealing ring is in contact with the side face, far away from the second pole shoe, of the first pole shoe, the sixth sealing ring is matched in the fourth annular groove, and the sixth sealing ring is in contact with the side face, far away from the first pole shoe, of the second pole shoe.

In some embodiments, the outer peripheral wall has a first through hole communicating with the sealed cavity.

In some embodiments, the first pole piece and/or the second pole piece has a second through hole, one end of the second through hole is communicated with the first through hole, and the other end of the second through hole is communicated with the sealing gap.

In some embodiments, the magnetic fluid reciprocating sealing device further includes a first bearing and a second bearing, the first bearing and the second bearing are both sleeved on the reciprocating shaft, the magnetic sealing element, the first magnetism isolating ring and the second magnetism isolating ring are all located between the first bearing and the second bearing, and the sealing cavity is formed between the first bearing, the reciprocating shaft, the peripheral wall and the second bearing.

In some embodiments, the magnetic liquid reciprocating sealing device further comprises a first sleeve ring and a second sleeve ring, the first sleeve ring and the second sleeve ring are both sleeved on the reciprocating shaft, the first sleeve ring is located between the first bearing and the first magnetism isolating ring, and the second sleeve ring is located between the second bearing and the second magnetism isolating ring.

In some embodiments, the inner diameter of the first pole piece and the inner diameter of the second pole piece are both smaller than the inner diameter of the permanent magnet.

In some embodiments, the permanent magnet and the first pole piece and the permanent magnet and the second pole piece are bonded or connected through a pin.

In some embodiments, the housing includes a cylindrical member and an end cap, the outer peripheral wall being a peripheral wall of the cylindrical member, the cavity being formed in the cylindrical member, the cylindrical member including a first end and a second end disposed opposite to each other along a length thereof, the first end of the cylindrical member being openly disposed to open the first end of the cavity, the end cap being disposed at the first end of the cylindrical member to close the first end of the cavity.

Drawings

Fig. 1 is a schematic view of a magnetic liquid reciprocating sealing device according to an embodiment of the present invention.

Fig. 2 is a partially enlarged view of fig. 1.

Fig. 3 is a schematic view of a housing of a magnetic liquid reciprocating sealing device according to an embodiment of the present invention.

Reference numerals:

a housing 100; a cylindrical member 110; a first through-hole 111; a flange 120; a connection hole 121; an end cap 130; a cavity 140; a sealed cavity 150; a seal gap 160; a third through hole 170; a fourth through hole 180; a reciprocating shaft 200; a magnetic seal 300; a permanent magnet 301; a first pole piece 302; a second through hole 3021; a second pole piece 303; a first slip ring seal 400; a first C-shaped slip ring 401; a first seal ring 402; a second slip ring seal 500; a second C-shaped slip ring 501; a second seal ring 502; a first magnetism isolating ring 410; a second magnetism isolating ring 510; a third seal ring 411; a fourth seal ring 511; a fifth seal 412; a sixth seal 512; a first collar 600; a second collar 700; a first bearing 800; a second bearing 900.

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 exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention.

As shown in fig. 1 to 3, a magnetic fluid reciprocating sealing device according to an embodiment of the present invention includes a housing 100, a reciprocating shaft 200, a power-up device (not shown), and a magnetic sealing member 300.

As shown in fig. 1 and 3, the housing 100 includes an outer peripheral wall 101 and a cavity 140 surrounded by the outer peripheral wall 101, the cavity 140 includes a sealed cavity 150, and the sealed cavity 150 is filled with a magnetic liquid.

As shown in fig. 1 and 2, the reciprocating shaft 200 is disposed on the housing 100 along an axial direction thereof, the reciprocating shaft 200 is movable relative to the housing 100 along the axial direction (the left-right direction shown in fig. 1) of the reciprocating shaft 200, at least a portion of the reciprocating shaft 200 is located in the cavity 140, and the axial direction of the reciprocating shaft 200 is substantially parallel to the longitudinal direction (the left-right direction shown in fig. 1) of the outer circumferential wall 101.

As shown in fig. 1, a power applying device is connected to the reciprocating shaft 200, and the power applying device is used for applying an axial current to the reciprocating shaft 200 to generate a magnetic field that is weakened from the inside to the outside in a radial direction of the reciprocating shaft 200. Specifically, the power-on device of the magnetic fluid reciprocating sealing device of the embodiment of the present invention is connected to the first end 201 of the reciprocating shaft and the second end 202 of the reciprocating shaft through two wires. The energizing means are thus able to pass an axial current to the reciprocating shaft 200, so as to be able to generate a magnetic field that weakens from the inside to the outside in the radial direction of the reciprocating shaft 200.

As shown in fig. 1 and 2, the magnetic sealing member 300 is located in the sealing cavity 150, the magnetic sealing member 300 is sleeved on the reciprocating shaft 200, an outer circumferential surface of the magnetic sealing member 300 is in contact with an inner circumferential surface of the outer circumferential wall 101, a sealing gap 160 is formed between the inner circumferential surface of the magnetic sealing member 300 and the outer circumferential surface of the reciprocating shaft 200, and the magnetic liquid is suitable for being absorbed in the sealing gap 160 under the magnetic force.

Further, as shown in fig. 1 and 2, the reciprocating shaft 200 is made of a magnetic conductive material, a magnetic circuit is formed between the magnetic sealing member 300 and the reciprocating shaft 200, a strong magnetic field gradient is formed in the sealing gap 160 by the magnetic circuit, the magnetic liquid is subjected to the action of the magnetic field force under the magnetic field gradient, and the magnetic liquid can be adsorbed in the sealing gap 160 under the magnetic action force.

According to the utility model discloses magnetic fluid reciprocating seal device lets in axial current to reciprocating shaft 200 through adding the electric installation, makes reciprocating shaft 200 produce annular magnetic field. The annular magnetic field is weakened from the inside to the outside in the radial direction of the reciprocating shaft 200, and the magnetic field is strongest at the outer circumferential surface of the reciprocating shaft 200 in the annular magnetic field. The magnetic liquid tends to a stronger magnetic field in the magnetic field, and thus the magnetic liquid adheres to the outer circumferential surface of the reciprocating shaft 200. Therefore, the magnetic liquid reciprocating sealing device can prevent the magnetic liquid in the sealing gap 160 from being lost outwards along with the movement of the reciprocating shaft 200, and is beneficial to the magnetic liquid outside the sealing gap 160 to be supplemented into the sealing gap 160 along with the reciprocating shaft 200, so that the sealing effect can be improved, and the service life can be prolonged.

Further, the material of the casing 100 is a non-magnetic material. Thus, the case 100 made of a non-magnetic material can prevent the magnetic circuit from leaking, and stabilize the magnetic field gradient in the seal gap 160.

Further, as shown in fig. 1 and 3, the outer peripheral wall 101 has a first through hole 111, and the first through hole 111 communicates with the seal chamber 150. So that the magnetic liquid is injected into the hermetic chamber 150 through the first through hole 111.

Further, as shown in fig. 1 and 3, the housing 100 includes a cylindrical member 110 and an end cap 130, the outer peripheral wall 101 is a peripheral wall of the cylindrical member 110, the cavity 140 is formed in the cylindrical member 110, the cylindrical member 110 includes a first end 112 and a second end 113 which are oppositely arranged along a length direction (left and right directions shown in fig. 1) of the cylindrical member, for example, the first end 112 of the cylindrical member is a right end of the cylindrical member, the second end 113 of the cylindrical member is a left end of the cylindrical member, the first end 112 of the cylindrical member is open to open a first end 141 of the cavity (e.g., a right end of the cavity), and the end cap 130 is disposed at the first end 112 of the cylindrical member to close the first end 141 of the cavity.

Further, as shown in fig. 1 and 3, the second end 113 of the cylindrical member has a third through hole 170, the end cap 130 has a fourth through hole 180, the first end 201 of the reciprocating shaft passes through the housing 100 from the third through hole 170, and the second end 202 of the reciprocating shaft passes through the housing 100 from the fourth through hole 180.

Further, as shown in fig. 1 and 3, the second end 113 of the cylindrical member has a flange 120, and the flange 120 has connection holes 121 spaced apart from each other, so that the housing 100 is fixedly mounted by the flange 120.

In some embodiments, as shown in fig. 1 and 2, magnetic seal 300 includes a first pole piece 302, a second pole piece 303, and a permanent magnet 301.

As shown in fig. 1 and 2, the first pole piece 302 and the second pole piece 303 are both sleeved on the reciprocating shaft 200, and the sealing gap 160 is formed between the first pole piece 302 and the reciprocating shaft 200 and between the second pole piece 303 and the reciprocating shaft 200. The first pole piece 302 and the second pole piece 303 are arranged at intervals along the axial direction of the reciprocating shaft 200, and the outer circumferential surface of the first pole piece 302 and the outer circumferential surface of the second pole piece 303 are both in contact with the inner circumferential surface of the outer circumferential wall 101.

Further, as shown in fig. 1 and 2, the first pole piece 302 and/or the second pole piece 303 has a second through hole 3021, one end of the second through hole 3021 communicates with the first through hole 111, and the other end of the second through hole 3021 communicates with the seal gap 160. The magnetic liquid is convenient to be directly injected into the sealing gap 160, the internal structure and the space of the sealing device can be fully utilized, and the overall size of the sealing device is reduced.

As shown in fig. 1 and 2, the permanent magnet 301 is sleeved on the reciprocating shaft 200, a gap is formed between the permanent magnet 301 and the reciprocating shaft 200, the outer circumferential surface of the permanent magnet 301 is in contact with the inner circumferential surface of the outer circumferential wall 101, and the permanent magnet 301 is connected between the first pole piece 302 and the second pole piece 303. Thereby, a stable magnetic circuit is formed among the permanent magnet 301, the first pole piece 302, the reciprocating shaft 200, and the second pole piece 303.

In some embodiments, the permanent magnet 301, the first pole piece 302, and the second pole piece 303 are all circular rings, and the inner diameter of the first pole piece 302 gradually decreases in a direction approaching the second pole piece 303, and the inner diameter of the second pole piece 303 gradually decreases in a direction away from the first pole piece 302. In other words, the inner circumferential surfaces of the first pole piece 302 and the second pole piece 303 are conical surfaces. That is, the seal gap 160 at the first and second pole pieces 302 and 303 gradually decreases in the direction from left to right. Therefore, the magnetic liquid can form a liquid sealing ring at the minimum position of the sealing gap 160, and further the loss of the magnetic liquid can be hindered to a certain extent.

Further, the inner diameter of the first pole piece 302 and the inner diameter of the second pole piece 303 are both smaller than the inner diameter of the permanent magnet 301, so that the permanent magnet 301 is ensured to be completely conducted with magnetism through the first pole piece 302 and the second pole piece 303, and the magnetic field gradient in the seal gap 160 is improved.

Further, the permanent magnet 301 and the first pole piece 302, and the permanent magnet 301 and the second pole piece 303 are bonded or connected through pins. Thereby, relative rotation between the permanent magnet 301 and the first pole piece 302 and between the permanent magnet 301 and the second pole piece 303 is avoided.

In some embodiments, as shown in fig. 1, the magnetic-fluid reciprocating sealing device further comprises a first magnetism isolating ring 410 and a second magnetism isolating ring 510. The first magnetism isolating ring 410 and the second magnetism isolating ring 510 are disposed in the sealing chamber 150 and spaced apart from each other in the axial direction of the reciprocating shaft 200. Gaps are formed between the first magnetism isolating ring 410 and the second magnetism isolating ring 510 and the reciprocating shaft 200, the outer peripheral surface of the first magnetism isolating ring 410 and the outer peripheral surface of the second magnetism isolating ring 510 are in contact with the inner peripheral surface of the outer peripheral wall 101, the end surface of the first magnetism isolating ring 410, which is adjacent to the second magnetism isolating ring 510, is in contact with the first pole shoe 302, and the end surface of the second magnetism isolating ring 510, which is adjacent to the first magnetism isolating ring 410, is in contact with the second pole shoe 303.

The first magnetism isolating ring 410 and the second magnetism isolating ring 510 are arranged at left and right intervals, the magnetic sealing element 300 is located between the first magnetism isolating ring 410 and the second magnetism isolating ring 510, the first magnetism isolating ring 410 isolates the first pole shoe 302 from other parts, and the first magnetism isolating ring 410 isolates the second pole shoe 303 from other parts. Therefore, the magnetic liquid reciprocating sealing device provided by the embodiment of the utility model can avoid the leakage of the magnetic circuit between the permanent magnet 301, the first pole shoe 302, the reciprocating shaft 200 and the second pole shoe 303, so that the magnetic field gradient in the sealing gap 160 is stable.

In some embodiments, as shown in fig. 1 and 2, the magnetic liquid reciprocating sealing device further comprises a first and a second slip ring seal 400, 500. The inner circumferential surface of the first magnetism isolating ring 410 is provided with a first annular groove, the inner circumferential surface of the second magnetism isolating ring 510 is provided with a second annular groove, the first slip ring seal 400 is fitted in the first annular groove, and the second slip ring seal 500 is fitted in the second annular groove. The inner circumferential surface of the first slip ring seal 400 and the inner circumferential surface of the second slip ring seal 500 are in contact with the outer circumferential surface of the reciprocating shaft 200. The first and second slip ring seals 400 and 500 can block leakage of the magnetic liquid.

In some embodiments, first slip ring seal 400 includes a first C-shaped slip ring 401 and a first seal ring 402. Second slip ring seal 500 includes a second C-shaped slip ring 501 and a second seal ring 502. The first seal ring 402 is located between the outer circumferential surface of the first C-shaped slip ring 401 and the bottom wall surface of the first annular groove, and the inner circumferential surface of the first C-shaped slip ring 401 is in contact with the outer circumferential surface of the reciprocating shaft 200. The second seal ring 502 is located between the outer peripheral surface of the second C-shaped slip ring 501 and the bottom wall surface of the second annular groove, and the inner peripheral surface of the second C-shaped slip ring 501 is in contact with the outer peripheral surface of the reciprocating shaft 200. Accordingly, the elastic force of the first seal ring 402 can make the inner peripheral surface of the first C-shaped slip ring 401 abut against the outer peripheral surface of the reciprocating shaft 200, and the elastic force of the second seal ring 502 can make the inner peripheral surface of the second C-shaped slip ring 501 abut against the outer peripheral surface of the reciprocating shaft 200. So that the leakage of the magnetic liquid from the gaps between the first and second magnetism isolating rings 410 and 510 and the outer circumferential surface of the reciprocating shaft 200 can be prevented.

Further, a side of the first annular groove adjacent to the second pole piece 303 penetrates through a side of the first magnetism isolating ring 410 adjacent to the second pole piece 303. The side of the first C-shaped slip ring 401 adjacent to the second pole piece 303 is in contact with the side of the first pole piece 302 away from the second pole piece 303, and the first sealing ring 402 is in contact with the side of the first pole piece 302 away from the second pole piece 303. The side of the second annular groove adjacent the first pole piece 302 extends through the side of the second magnetism isolating ring 510 adjacent the first pole piece 302. And the side of the second C-shaped slip ring 501 adjacent to the first pole piece 302 is in contact with the side of the second pole piece 303 far away from the first pole piece 302, and the second sealing ring 502 is in contact with the side of the second pole piece 303 far away from the first pole piece 302. Therefore, the first slip ring seal 400 can also seal the contact surface between the first magnetism isolating ring 410 and the first pole shoe 302, and the second slip ring seal 500 can also seal the contact surface between the second magnetism isolating ring 510 and the second pole shoe 303, so as to prevent the magnetic liquid from losing.

In some embodiments, the magnetic liquid reciprocating sealing device further comprises a third sealing ring 411 and a fourth sealing ring 511. The first magnetism isolating ring 410 has a first annular groove on the outer peripheral surface thereof, and the second magnetism isolating ring 510 has a second annular groove on the outer peripheral surface thereof. The third seal ring 411 is fitted in the first annular groove, and the first seal ring 402 is in contact with the inner peripheral surface of the outer peripheral wall 101. The fourth seal ring 511 is fitted in the second annular groove, and the second seal ring 502 is in contact with the inner peripheral surface of the outer peripheral wall 101. Accordingly, the third seal ring 411 can seal the contact surface between the first magnetism isolating ring 410 and the outer peripheral wall 101, and the fourth seal ring 511 can seal the contact surface between the second magnetism isolating ring 510 and the outer peripheral wall 101, thereby preventing the magnetic liquid from flowing out.

Further, the magnetic fluid reciprocating sealing device further comprises a fifth sealing ring 412 and a sixth sealing ring 512. The end surface of the first magnetism isolating ring 410 adjacent to the second magnetism isolating ring 510 is provided with a third annular groove, and the end surface of the second magnetism isolating ring 510 adjacent to the first magnetism isolating ring 410 is provided with a fourth annular groove. A fifth seal ring 412 fits within the third annular groove and the fifth seal ring 412 contacts the side of the first pole piece 302 remote from the second pole piece 303. The sixth sealing ring 512 is fitted in the fourth annular groove, and the sixth sealing ring 512 is in contact with the side of the second pole piece 303 away from the first pole piece 302. Therefore, the fifth sealing ring 412 can also seal the contact surface between the first magnetism isolating ring 410 and the first pole shoe 302, and the sixth sealing ring 512 can also seal the contact surface between the second magnetism isolating ring 510 and the second pole shoe 303, so as to avoid the loss of the magnetic liquid.

In some embodiments, as shown in fig. 1, the magnetic-fluid reciprocating seal device further comprises a first bearing 800 and a second bearing 900. The first bearing 800 and the second bearing 900 are both sleeved on the reciprocating shaft, the outer peripheral surface of the first bearing 800 is in contact with the inner wall surface of the third through hole 170, and the outer peripheral surface of the second bearing 900 is in contact with the inner wall surface of the fourth through hole 180. Therefore, the magnetic fluid reciprocating sealing device according to the embodiment of the present invention slidably inserts the reciprocating shaft 200 through the housing 100 via the first bearing 800 and the second bearing 900.

As shown in fig. 1, the magnetic sealing member 300, the first magnetism isolating ring 410 and the second magnetism isolating ring 510 are all located between the first bearing 800 and the second bearing 900, and the sealing cavity 150 is formed between the first bearing 800, the reciprocating shaft, the outer circumferential wall 101 and the second bearing 900. That is, the cavity 140 enclosed by the first bearing 800, the reciprocating shaft, the outer peripheral wall 101 and the second bearing 900 is the sealed cavity 150, and the magnetic sealing element 300, the first magnetism isolating ring 410 and the second magnetism isolating ring 510 are all located in the sealed cavity 150.

In some embodiments, as shown in fig. 1, the magnetic fluid reciprocating sealing device further comprises a first collar 600 and a second collar 700, the first collar 600 and the second collar 700 are both sleeved on the reciprocating shaft, the first collar 600 is located between the first bearing 800 and the first magnetism isolating ring 410, and the second collar 700 is located between the second bearing 900 and the second magnetism isolating ring 510. Specifically, the material of the first and second collars 600, 700 is also non-magnetic material. The first collar 600 can provide a locating function for the first bearing 800 and the second collar 700 can provide a locating function for the second bearing 900.

A specific exemplary magnetic liquid reciprocating sealing device according to the present invention is described below with reference to the accompanying drawings.

As shown in fig. 1 to 3, the magnetic fluid reciprocating sealing device according to the embodiment of the present invention includes a housing 100, a reciprocating shaft 200, a power-on device, a magnetic sealing element 300, a first magnetism isolating ring 410, a second magnetism isolating ring 510, a first slip ring sealing element 400, a second slip ring sealing element 500, a third sealing ring 411, a fourth sealing ring 511, a fifth sealing ring 412, a sixth sealing ring 512, a first collar 600, a second collar 700, a first bearing 800, and a second bearing 900.

The housing 100 includes an outer peripheral wall 101 and a cavity 140 surrounded by the outer peripheral wall 101, the cavity 140 includes a sealed cavity 150, and the sealed cavity 150 is filled with a magnetic liquid. The reciprocating shaft 200 is disposed through the housing 100 in a left-right direction, the reciprocating shaft 200 is movable relative to the housing 100 in an axial direction (left-right direction as viewed in fig. 1) of the reciprocating shaft 200, and at least a portion of the reciprocating shaft 200 is located in the cavity 140. The energizing means is connected to the reciprocating shaft 200, and the energizing means is used for applying an axial current to the reciprocating shaft 200 to generate a magnetic field that decreases from the inside to the outside in the radial direction of the reciprocating shaft 200.

The magnetic sealing member 300 is located in the sealing cavity 150, the magnetic sealing member 300 is sleeved on the reciprocating shaft 200, the outer circumferential surface of the magnetic sealing member 300 is in contact with the inner circumferential surface of the outer circumferential wall 101, a sealing gap 160 is formed between the inner circumferential surface of the magnetic sealing member 300 and the outer circumferential surface of the reciprocating shaft, and the magnetic liquid is suitable for being adsorbed in the sealing gap 160 under the magnetic acting force.

The reciprocating shaft 200 is made of a magnetic conductive material, the housing 100 is made of a non-magnetic conductive material, a magnetic circuit is formed between the magnetic sealing element 300 and the reciprocating shaft 200, a strong magnetic field gradient is formed in the sealing gap 160 by the magnetic circuit, the magnetic liquid is acted by the magnetic field force under the magnetic field gradient, and the magnetic liquid can be adsorbed in the sealing gap 160 under the magnetic action force.

The housing 100 includes a cylindrical member 110 and an end cap 130, the outer peripheral wall 101 is a peripheral wall of the cylindrical member 110, a cavity 140 is formed in the cylindrical member 110, a right end of the cylindrical member 110 is open to open a right end of the cavity 140, the end cap 130 is provided at a right end of the cylindrical member 110 to close the right end of the cavity 140, the outer peripheral wall 101 has a first through hole 111, and the first through hole 111 communicates with the seal chamber 150.

The left end of the cylindrical member 110 has a third through hole 170, the end cap 130 has a fourth through hole 180, the left end of the reciprocating shaft 200 passes through the housing 100 from the third through hole 170, the right end of the reciprocating shaft 200 passes through the housing 100 from the fourth through hole 180, the right end of the cylindrical member 110 has a flange 120, and the flange 120 has connecting holes 121 arranged at intervals so that the housing 100 is fixed by the flange 120.

Magnetic seal 300 includes a first pole piece 302, a second pole piece 303, and a permanent magnet 301. The first pole piece 302 and the second pole piece 303 are both sleeved on the reciprocating shaft 200, and the sealing gaps 160 are formed between the first pole piece 302 and the reciprocating shaft 200 and between the second pole piece 303 and the reciprocating shaft 200. The first pole piece 302 and the second pole piece 303 are arranged at intervals along the axial direction of the reciprocating shaft 200, and the outer circumferential surface of the first pole piece 302 and the outer circumferential surface of the second pole piece 303 are both in contact with the inner circumferential surface of the outer circumferential wall 101. The first pole piece 302 and/or the second pole piece 303 have a second through hole 3021, one end of the second through hole 3021 communicates with the first through hole 111, and the other end of the second through hole 3021 communicates with the seal gap 160.

The permanent magnet 301 is sleeved on the reciprocating shaft 200, a gap is formed between the permanent magnet 301 and the reciprocating shaft 200, the outer circumferential surface of the permanent magnet 301 is in contact with the inner circumferential surface of the outer circumferential wall 101, and the permanent magnet 301 is connected between the first pole piece 302 and the second pole piece 303.

The permanent magnet 301, the first pole piece 302 and the second pole piece 303 are all circular rings, the inner diameter of the first pole piece 302 is gradually reduced in a direction close to the second pole piece 303, and the inner diameter of the second pole piece 303 is gradually reduced in a direction far away from the first pole piece 302. In other words, the inner circumferential surfaces of the first pole piece 302 and the second pole piece 303 are conical surfaces. That is, the seal gap 160 at the first and second pole pieces 302 and 303 gradually decreases in the direction from left to right.

Further, the inner diameter of the first pole piece 302 and the inner diameter of the second pole piece 303 are both smaller than the inner diameter of the permanent magnet 301, so that the permanent magnet 301 is ensured to be completely conducted with magnetism through the first pole piece 302 and the second pole piece 303, and the magnetic field gradient in the seal gap 160 is improved.

Further, the permanent magnet 301 and the first pole piece 302, and the permanent magnet 301 and the second pole piece 303 are bonded or connected through pins. Thereby, relative rotation between the permanent magnet 301 and the first pole piece 302 and between the permanent magnet 301 and the second pole piece 303 is avoided.

The first magnetism isolating ring 410 and the second magnetism isolating ring 510 are disposed in the sealing chamber 150 and spaced apart from each other in the axial direction of the reciprocating shaft 200. Gaps are formed between the first magnetism isolating ring 410 and the second magnetism isolating ring 510 and the reciprocating shaft 200, the outer peripheral surface of the first magnetism isolating ring 410 and the outer peripheral surface of the second magnetism isolating ring 510 are in contact with the inner peripheral surface of the outer peripheral wall 101, the end surface of the first magnetism isolating ring 410, which is adjacent to the second magnetism isolating ring 510, is in contact with the first pole shoe 302, and the end surface of the second magnetism isolating ring 510, which is adjacent to the first magnetism isolating ring 410, is in contact with the second pole shoe 303.

The inner circumferential surface of the first magnetism isolating ring 410 is provided with a first annular groove, the inner circumferential surface of the second magnetism isolating ring 510 is provided with a second annular groove, the first slip ring seal 400 is fitted in the first annular groove, and the second slip ring seal 500 is fitted in the second annular groove. The inner circumferential surface of the first slip ring seal 400 and the inner circumferential surface of the second slip ring seal 500 are in contact with the outer circumferential surface of the reciprocating shaft 200. The first and second slip ring seals 400 and 500 can block leakage of the magnetic liquid.

The first slip ring seal 400 comprises a first C-shaped slip ring 401 and a first sealing ring 402. Second slip ring seal 500 includes a second C-shaped slip ring 501 and a second seal ring 502. The first seal ring 402 is located between the outer circumferential surface of the first C-shaped slip ring 401 and the bottom wall surface of the first annular groove, and the inner circumferential surface of the first C-shaped slip ring 401 is in contact with the outer circumferential surface of the reciprocating shaft 200. The second seal ring 502 is located between the outer peripheral surface of the second C-shaped slip ring 501 and the bottom wall surface of the second annular groove, and the inner peripheral surface of the second C-shaped slip ring 501 is in contact with the outer peripheral surface of the reciprocating shaft 200. Accordingly, the elastic force of the first seal ring 402 can make the inner peripheral surface of the first C-shaped slip ring 401 abut against the outer peripheral surface of the reciprocating shaft 200, and the elastic force of the second seal ring 502 can make the inner peripheral surface of the second C-shaped slip ring 501 abut against the outer peripheral surface of the reciprocating shaft 200. So that the leakage of the magnetic liquid from the gaps between the first and second magnetism isolating rings 410 and 510 and the outer circumferential surface of the reciprocating shaft 200 can be prevented.

One side of the first annular groove adjacent to the second pole piece 303 extends through a side of the first magnetism isolating ring 410 adjacent to the second pole piece 303. The side of the first C-shaped slip ring 401 adjacent to the second pole piece 303 is in contact with the side of the first pole piece 302 away from the second pole piece 303, and the first sealing ring 402 is in contact with the side of the first pole piece 302 away from the second pole piece 303. The side of the second annular groove adjacent the first pole piece 302 extends through the side of the second magnetism isolating ring 510 adjacent the first pole piece 302. And the side of the second C-shaped slip ring 501 adjacent to the first pole piece 302 is in contact with the side of the second pole piece 303 far away from the first pole piece 302, and the second sealing ring 502 is in contact with the side of the second pole piece 303 far away from the first pole piece 302. Therefore, the first slip ring seal 400 can also seal the contact surface between the first magnetism isolating ring 410 and the first pole shoe 302, and the second slip ring seal 500 can also seal the contact surface between the second magnetism isolating ring 510 and the second pole shoe 303, so as to prevent the magnetic liquid from losing.

The first magnetism isolating ring 410 has a first annular groove on the outer peripheral surface thereof, and the second magnetism isolating ring 510 has a second annular groove on the outer peripheral surface thereof. The third seal ring 411 is fitted in the first annular groove, and the third seal ring 411 is in contact with the inner peripheral surface of the outer peripheral wall 101. The fourth seal ring 511 is fitted in the second annular groove, and the fourth seal ring 511 is in contact with the inner peripheral surface of the outer peripheral wall 101. Accordingly, the third seal ring 411 can seal the contact surface between the first magnetism isolating ring 410 and the outer peripheral wall 101, and the fourth seal ring 511 can seal the contact surface between the second magnetism isolating ring 510 and the outer peripheral wall 101, thereby preventing the magnetic liquid from flowing out.

The end surface of the first magnetism isolating ring 410 adjacent to the second magnetism isolating ring 510 is provided with a third annular groove, and the end surface of the second magnetism isolating ring 510 adjacent to the first magnetism isolating ring 410 is provided with a fourth annular groove. A fifth seal ring 412 fits within the third annular groove and the fifth seal ring 412 contacts the side of the first pole piece 302 remote from the second pole piece 303. The sixth sealing ring 512 is fitted in the fourth annular groove, and the sixth sealing ring 512 is in contact with the side of the second pole piece 303 away from the first pole piece 302.

The first bearing 800 and the second bearing 900 are both sleeved on the reciprocating shaft, the outer peripheral surface of the first bearing 800 is in contact with the inner wall surface of the third through hole 170, and the outer peripheral surface of the second bearing 900 is in contact with the inner wall surface of the fourth through hole 180. The magnetic sealing member 300, the first magnetism isolating ring 410 and the second magnetism isolating ring 510 are all located between the first bearing 800 and the second bearing 900, and the sealing cavity 150 is formed between the first bearing 800, the reciprocating shaft, the outer peripheral wall 101 and the second bearing 900. That is, the cavity 140 enclosed by the first bearing 800, the reciprocating shaft, the outer peripheral wall 101 and the second bearing 900 is the sealed cavity 150, and the magnetic sealing element 300, the first magnetism isolating ring 410 and the second magnetism isolating ring 510 are all located in the sealed cavity 150.

The first lantern ring 600 and the second lantern ring 700 are sleeved on the reciprocating shaft, the first lantern ring 600 is located between the first bearing 800 and the first magnetism isolating ring 410, and the second lantern ring 700 is located between the second bearing 900 and the second magnetism isolating ring 510. Specifically, the material of the first and second collars 600, 700 is also non-magnetic material. The first collar 600 can provide a locating function for the first bearing 800 and the second collar 700 can provide a locating function for the second bearing 900.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship indicated based on the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present 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," and "fixed" are to be construed broadly and may, 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 meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present application, unless expressly stated or limited otherwise, the first feature may be directly on or directly under the second feature or indirectly via intermediate members. 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" or the like 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 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, 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 without departing from the scope of the present invention.

Claims (15)

1. A magnetic fluid reciprocating seal apparatus, comprising:

the magnetic liquid separation device comprises a shell, a magnetic liquid separation device and a magnetic liquid separation device, wherein the shell comprises an outer peripheral wall and a cavity surrounded by the outer peripheral wall, the cavity comprises a sealing cavity, and the sealing cavity is filled with magnetic liquid;

the reciprocating shaft penetrates through the shell along the axial direction of the reciprocating shaft, the reciprocating shaft can move relative to the shell along the axial direction of the reciprocating shaft, at least part of the reciprocating shaft is positioned in the cavity, and the axial direction of the reciprocating shaft is generally parallel to the length direction of the peripheral wall;

the power-on device is connected with the reciprocating shaft and used for introducing axial current to the reciprocating shaft to generate a magnetic field weakened from inside to outside in the radial direction of the reciprocating shaft;

the magnetic sealing element is positioned in the sealing cavity, the magnetic sealing element is sleeved on the reciprocating shaft, the outer peripheral surface of the magnetic sealing element is in contact with the inner peripheral surface of the outer peripheral wall, a sealing gap is formed between the inner peripheral surface of the magnetic sealing element and the outer peripheral surface of the reciprocating shaft, and the magnetic liquid is suitable for being adsorbed in the sealing gap under the action of magnetic force.

2. The magnetic liquid reciprocating seal apparatus of claim 1, wherein the magnetic seal comprises:

the first pole shoe and the second pole shoe are sleeved on the reciprocating shaft, the sealing gaps are formed between the first pole shoe and the reciprocating shaft and between the second pole shoe and the reciprocating shaft, the first pole shoe and the second pole shoe are arranged at intervals along the axial direction of the reciprocating shaft, and the outer peripheral surface of the first pole shoe and the outer peripheral surface of the second pole shoe are both contacted with the inner peripheral surface of the outer peripheral wall; and

the permanent magnet is sleeved on the reciprocating shaft, a gap is formed between the permanent magnet and the reciprocating shaft, the outer peripheral surface of the permanent magnet is in contact with the inner peripheral surface of the outer peripheral wall, and the permanent magnet is connected between the first pole shoe and the second pole shoe.

3. The magnetic liquid reciprocating sealing device according to claim 2, wherein the permanent magnet, the first pole piece and the second pole piece are all circular rings, the inner diameter of the first pole piece is gradually reduced in a direction close to the second pole piece, and the inner diameter of the second pole piece is gradually reduced in a direction far away from the first pole piece.

4. The magnetic fluid reciprocating sealing device according to claim 2, further comprising a first magnetism isolating ring and a second magnetism isolating ring, wherein the first magnetism isolating ring and the second magnetism isolating ring are disposed in the sealing cavity and are spaced apart from each other in an axial direction of the reciprocating shaft, a gap is provided between the first magnetism isolating ring and the reciprocating shaft, an outer circumferential surface of the first magnetism isolating ring and an outer circumferential surface of the second magnetism isolating ring contact an inner circumferential surface of the outer circumferential wall, an end surface of the first magnetism isolating ring adjacent to the second magnetism isolating ring contacts the first pole shoe, and an end surface of the second magnetism isolating ring adjacent to the first magnetism isolating ring contacts the second pole shoe.

5. The magnetic fluid reciprocating sealing device according to claim 4, further comprising a first slip ring seal and a second slip ring seal, wherein the inner circumferential surface of the first magnetism isolating ring is provided with a first annular groove, the inner circumferential surface of the second magnetism isolating ring is provided with a second annular groove, the first slip ring seal is fitted in the first annular groove, the second slip ring seal is fitted in the second annular groove, and the inner circumferential surface of the first slip ring seal and the inner circumferential surface of the second slip ring seal are both in contact with the outer circumferential surface of the reciprocating shaft.

6. The magnetic liquid reciprocating seal apparatus of claim 5, wherein the first slip ring seal comprises a first C-shaped slip ring and a first seal ring, and the second slip ring seal comprises a second C-shaped slip ring and a second seal ring;

the first sealing ring is positioned between the outer peripheral surface of the first C-shaped sliding ring and the bottom wall surface of the first annular groove, the inner peripheral surface of the first C-shaped sliding ring is in contact with the outer peripheral surface of the reciprocating shaft,

the second sealing ring is located between the outer peripheral surface of the second C-shaped sliding ring and the bottom wall surface of the second annular groove, and the inner peripheral surface of the second C-shaped sliding ring is in contact with the outer peripheral surface of the reciprocating shaft.

7. The magnetic liquid reciprocating seal apparatus of claim 6, wherein a side of the first annular groove adjacent to the second pole piece passes through a side of the first magnetism isolating ring adjacent to the second pole piece, and a side of the first C-shaped slip ring adjacent to the second pole piece contacts a side of the first pole piece remote from the second pole piece, the first seal ring contacts a side of the first pole piece remote from the second pole piece;

one side of the second annular groove, which is adjacent to the first pole shoe, penetrates through the side face, which is adjacent to the first pole shoe, of the second magnetism isolating ring, one side, which is adjacent to the first pole shoe, of the second C-shaped sliding ring is in contact with the side face, which is far away from the first pole shoe, of the second pole shoe, and the second sealing ring is in contact with the side face, which is far away from the first pole shoe, of the second pole shoe.

8. The magnetic liquid reciprocating sealing device according to claim 6, further comprising a third sealing ring and a fourth sealing ring, wherein the outer peripheral surface of the first magnetism isolating ring has a first annular groove, and the outer peripheral surface of the second magnetism isolating ring has a second annular groove;

the third sealing ring is matched in the first annular groove, and the first sealing ring is contacted with the inner circumferential surface of the outer circumferential wall,

the fourth sealing ring is matched in the second annular groove, and the second sealing ring is in contact with the inner circumferential surface of the outer circumferential wall.

9. The magnetic liquid reciprocating sealing device according to claim 4, further comprising a fifth sealing ring and a sixth sealing ring, wherein a third annular groove is formed on the end surface of the first magnetism isolating ring adjacent to the second magnetism isolating ring, and a fourth annular groove is formed on the end surface of the second magnetism isolating ring adjacent to the first magnetism isolating ring;

the fifth sealing ring is matched in the third annular groove and is in contact with the side surface of the first pole shoe far away from the second pole shoe,

the sixth sealing ring is matched in the fourth annular groove, and the sixth sealing ring is in contact with the side face, far away from the first pole shoe, of the second pole shoe.

10. The magnetic liquid reciprocating sealing device according to claim 2, wherein the outer peripheral wall has a first through hole communicating with the seal cavity.

11. The magnetic liquid reciprocating sealing device according to claim 10, wherein the first pole piece and/or the second pole piece is provided with a second through hole, one end of the second through hole is communicated with the first through hole, and the other end of the second through hole is communicated with the sealing gap.

12. The magnetic fluid reciprocating sealing device of claim 4, further comprising a first bearing and a second bearing, wherein the first bearing and the second bearing are both sleeved on the reciprocating shaft, the magnetic sealing element, the first magnetism isolating ring and the second magnetism isolating ring are all located between the first bearing and the second bearing, and the sealing cavity is formed between the first bearing, the reciprocating shaft, the peripheral wall and the second bearing.

13. The magnetic fluid reciprocating sealing device of claim 12, further comprising a first collar and a second collar, both of which are sleeved on the reciprocating shaft, wherein the first collar is located between the first bearing and the first magnetism isolating ring, and the second collar is located between the second bearing and the second magnetism isolating ring.

14. The magnetic liquid reciprocating sealing device according to any one of claims 2 to 13, wherein the permanent magnet and the first pole piece and the permanent magnet and the second pole piece are bonded or connected through a pin.

15. The magnetic liquid reciprocating sealing device according to any one of claims 2 to 13, wherein the housing includes a cylindrical member and an end cap, the outer peripheral wall is a peripheral wall of the cylindrical member, the cavity is formed in the cylindrical member, the cylindrical member includes a first end and a second end which are oppositely arranged along a length direction thereof, the first end of the cylindrical member is openly disposed to open the first end of the cavity, and the end cap is disposed at the first end of the cylindrical member to close the first end of the cavity.

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