CN113993318A

CN113993318A - Wireless optical frequency demodulator with anti-interference structure

Info

Publication number: CN113993318A
Application number: CN202111262968.8A
Authority: CN
Inventors: 夏永文
Original assignee: Xuzhou Zhigu Optical Frequency Industry Research Institute Co ltd
Current assignee: Xuzhou Zhigu Optical Frequency Industry Research Institute Co ltd
Priority date: 2021-10-28
Filing date: 2021-10-28
Publication date: 2022-01-28

Abstract

The invention provides a wireless optical frequency demodulator with an anti-interference structure, which relates to the technical field of optical frequency demodulators and solves the problems that the dust accumulation of the existing optical frequency demodulator can block or have electrostatic influence on the normal operation of a device, and excessive moisture in a humid environment enters the device to easily cause the short circuit of an original element in the device, the wireless optical frequency demodulator comprises a shell, wherein a guide groove is formed in the shell and used for assembling a guide block, a bellows is fixedly connected to the left side of the shell, fans are arranged in the bellows in a linear array manner, an air outlet is formed in the left side of the interior of the shell and matched with an air inlet, the bellows is communicated with the air outlet, a cover plate is connected to the top end of the shell in a sliding manner, moisture contained in air flow is filtered by a moisture-proof pad inserted into the inner side of the cover plate and then enters the interior of the shell to carry out dust removal operation, then the air is discharged outside through an air overflow port arranged on the right side of the shell.

Description

Wireless optical frequency demodulator with anti-interference structure

Technical Field

The invention belongs to the technical field of optical frequency demodulators, and particularly relates to a wireless optical frequency demodulator with an anti-interference structure.

Background

The optical frequency demodulator is also called a single-port optical transceiver, and is a three-piece optical fiber transmission device developed for special user environments.

The existing optical frequency demodulator has the following defects:

1. mostly lie in on the desktop and lean on the wall to put for the device outside can cover a large amount of dust along with time, and the dust is piled up and can be produced jam or electrostatic effect to the normal work of device, and too much moisture enters into the inside condition that causes the inside original paper of device to appear the short circuit easily of device in humid environment.

2. The wiring end is arranged at the rear side of the optical frequency demodulator, so that when the optical frequency demodulator is placed, the wiring harness connected is easily bent due to bending to affect normal use, and the connection wiring harness of the optical frequency demodulator is connected with the optical frequency demodulator and then cannot be effectively connected in an anti-interference mode, so that the situation that the normal use of the optical frequency demodulator is affected due to interference exists.

Disclosure of Invention

In order to solve the technical problems, the invention provides a wireless optical frequency demodulator with an anti-interference structure, which aims to solve the problems that the dust accumulation of the existing optical frequency demodulator can cause blockage or electrostatic influence on the normal operation of the device, and the normal use is easily influenced by the bending of a connected wire harness caused by bending when the wireless optical frequency demodulator is placed.

The invention relates to a wireless optical frequency demodulator with an anti-interference structure, which is achieved by the following specific technical means:

a wireless optical frequency demodulator with an anti-interference structure comprises a shell;

the utility model discloses a fan, including casing, air outlet, air inlet, air box, air inlet, air outlet, guide way, air box, fan cover, air outlet, air box, fan cover, casing, air box, fan cover, casing, air box and the top sliding connection of casing has the apron.

Furthermore, the rear side of the sliding groove formed in the bottom end of the shell is fixedly connected with a baffle plate, the rear end face of each sliding groove is fixedly connected with two baffle plates, a gap is formed between the two baffle plates, the gap between the two baffle plates is larger than the diameter of the through round hole formed in the mounting block, and therefore when the wire harness is inserted into the mounting block, the baffle plates cannot block the wire harness.

Furthermore, the apron is inside hollow structure, and the top side and the bottom side of apron all are linear array and have seted up the radiating groove, and the wind gap has been seted up to the left end of apron, and the inside grafting of apron has dampproofing the pad, and the bottom face fixedly connected with guide block of apron, guide block are equipped with two altogether, and two guide block difference fixed connection is in the left and right sides of apron bottom face front end.

Further, the equal fixedly connected with stopper of both ends face central point puts about the installation piece, and the round hole that link up is seted up to the inside of installation piece, and the magnetism post is inhaled all around to fixedly connected with at the preceding terminal surface of installation piece, and magnetism post is the rectangular array setting, and the width of installation piece is greater than the interval between the two bafflers, and then the accessible utilizes the baffler to carry on spacingly to the installation piece, and the inside fixedly connected with connecting block of casing still is linear array in the inside of connecting block and has seted up the interface, and the interface is used for external module.

Furthermore, the front end of the installation block is fixedly connected with an anti-interference ring, the anti-interference ring is of a spiral structure, the installation block is fixedly connected with the front end face of the sliding groove through the anti-interference ring, the bottom side of the installation block is hinged with a handle, the anti-interference ring of the spiral structure can perform anti-interference and anti-bending protection on the inserted wire harness, and the right side of the shell is provided with an air overflow port.

Furthermore, the bottom side of casing has seted up the spout, and the spout all has seted up the inside groove in the inside left and right sides of every spout with installation piece phase-match, inside groove and stopper phase-match, still seted up the spacing groove in the bottom of casing, spacing groove and handle phase-match.

Further, the inside round hole of seting up of installation piece is inside still to install the magnetic ring through reset spring, and the magnetic ring is the semi-ring structure, and the magnetic ring of every two subtend installations is a set of, installs two reset spring between the inner wall of every magnetic ring and the inside trompil of installation piece, still is arc array fixedly connected with limiting plate on the inner wall of magnetic ring, and the magnetic ring of arc structure can play more comprehensive parcel effect to male pencil to the twitch of pencil is restricted to the accessible limiting plate, and the interference killing feature of pencil is further promoted through the magnetic ring.

Further, the bottom face rear side of casing is fixedly connected with baffle still, and the inside of baffle is linear array and has seted up the square groove, and the length of baffle and the biggest width phase-match of the fluting of spout, and then when the pencil inserts the square groove that the inside was seted up of accessible baffle carries out the box to the pencil and accomodate to reach more practical purpose, the spacing groove link up with the spout mutually, still is the rectangle array on the preceding terminal surface of spout and has seted up four magnetism suction holes, magnetism suction hole and magnetism suction column phase-match.

Compared with the prior art, the invention has the following beneficial effects:

1. the inside cavity of having seted up of casing, and still install the connecting block in the inside of cavity, the interface has been seted up to the inside of connecting block, and then pass through the interface with external module when inserting the connecting block inside as required, need slide the expansion back and just can connect the guide block of lapping through its bottom side fixed connection along the inside guide way of seting up of casing, and then ensured that external module is located the inside position of casing when being connected with the connecting block, this design can effectual solution because of the outside that traditional external module is located the casing, the condition of bending of interface appears because of colliding with easily.

2. The left side of casing is provided with bellows, and still be linear array in the inside of bellows and be provided with the heat dissipation fan, and then when the heat dissipation fan rotated through motor drive, the inside air outlet of seting up of accessible casing enters into the inboard position of apron with the distinguished and admirable income wind gap of seting up on the left of the apron, then the inside that enters into the casing after the moisture that contains in the distinguished and admirable of apron inboard inserted filters it removes dust operation, then arrange outward through the excessive wind gap that the casing right side was seted up, and then reached and prevented to appear because of placing the condition that can remain the dust on the device for a long time.

3. The wire harness installing block is provided with an installing block, the round hole arranged inside the installing block is internally and elastically connected with an arc-shaped magnetic ring through a reset spring, the reset spring can be self-adaptive after the wire harness is inserted to clamp the wire harness through the magnetic ring, the inner wall of the magnetic ring is also provided with an arc-shaped array fixedly connected with limiting plate, the wire harness can be prevented from being pulled out by mistake after the wire harness is inserted into the inner side of the magnetic ring, and the anti-interference ring is fixedly connected with the anti-interference ring at the front side of the installing block, so that the anti-interference ring and the magnetic ring can be used for carrying out efficient anti-interference and anti-bending operation on the wire harness after the wire harness is inserted.

Drawings

Fig. 1 is a schematic front side view of the present invention in a disassembled state.

Fig. 2 is a schematic bottom side view of the present invention in a disassembled state.

Fig. 3 is a schematic side view of the shaft in the disassembled state.

Fig. 4 is a schematic view of the assembled structure of the present invention.

Fig. 5 is a schematic view of the structure of the housing, connecting block, mouthpiece, bellows, cover plate, moisture-proof pad and baffle of the present invention.

Fig. 6 is a schematic view showing a structure from the mounting block to the limiting plate according to the present invention.

Fig. 7 is a schematic bottom view of the present invention.

Fig. 8 is an enlarged schematic view of the structure at a in fig. 3 according to the present invention.

Fig. 9 is a left side view structural diagram in the disassembled state of the present invention.

Fig. 10 is an enlarged view of the structure of fig. 9 at B according to the present invention.

In the drawings, the corresponding relationship between the component names and the reference numbers is as follows:

1. a housing; 2. connecting blocks; 3. an interface; 4. an air outlet; 5. an air overflow opening; 6. a guide groove; 7. an air box; 8. a cover plate; 9. a guide block; 10. a moisture-proof pad; 11. an air inlet; 12. a heat dissipation fan; 13. a chute; 14. a limiting groove; 15. blocking the plate; 16. a baffle plate; 17. an inner tank; 18. mounting blocks; 19. a magnetic attraction column; 20. a limiting block; 21. an anti-interference ring; 22. a handle; 23. a magnetic ring; 24. a return spring; 25. and a limiting plate.

Detailed Description

The embodiments of the present invention will be described in further detail with reference to the drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

First embodiment

As shown in figures 1 to 10:

the invention provides a wireless optical frequency demodulator with an anti-interference structure, which comprises: casing 1, guide way 6 has been seted up to casing 1's inside, guide way 6 is used for assembling guide block 9, fixedly connected with bellows 7 is still in casing 1's left side, is the linear array in bellows 7's inside and installs the fan, and air outlet 4 has still been seted up in casing 1's inside left side, and air outlet 4 and income wind gap 11 phase-match, and bellows 7 link up with air outlet 4 mutually, and the inside of bellows 7 is the linear array and installs heat dissipation fan 12, and casing 1's top sliding connection has apron 8.

Referring to fig. 1-3, the cover plate 8 is a hollow structure, the top and bottom sides of the cover plate 8 are provided with heat dissipation grooves in a linear array, the left end of the cover plate 8 is provided with an air inlet 11, the cover plate 8 is inserted with a moisture-proof pad 10, the bottom end surface of the cover plate 8 is fixedly connected with guide blocks 9, the guide blocks 9 are provided with two positions, the two guide blocks 9 are respectively and fixedly connected with the left and right sides of the front end of the bottom end surface of the cover plate 8, the bottom side of the housing 1 is provided with a sliding groove 13, the sliding groove 13 is matched with an installation block 18, the left and right sides of the inside of each sliding groove 13 are provided with inner grooves 17, the inner grooves 17 are matched with limit blocks 20, the bottom end of the housing 1 is further provided with limit grooves 14, the limit grooves 14 are matched with handles 22, the inside of the housing 1 is fixedly connected with a connecting block 2, the inside of the connecting block 2 is provided with interfaces 3 in a linear array, the interfaces 3 are used for external connection of a module, the right side of the shell 1 is provided with an air overflow opening 5.

Referring to fig. 4-7, a baffle 16 is fixedly connected to the rear side of the bottom end surface of the housing 1, a square groove is formed in the baffle 16 in a linear array, the length of the baffle 16 is matched with the maximum width of the groove of the chute 13, when the wiring harness is inserted, the wiring harness can be divided into grids to be accommodated through the square groove formed in the baffle plate 16, so as to achieve the more practical purpose, the limiting groove 14 is communicated with the sliding groove 13, four magnetic attraction holes are further arranged on the front end face of the sliding groove 13 in a rectangular array and are matched with the magnetic attraction columns 19, the central positions of the left end face and the right end face of the mounting block 18 are fixedly connected with limiting blocks 20, a through round hole is arranged inside the mounting block 18, still fixedly connected with four magnetism post 19 of inhaling before installation piece 18, magnetism post 19 is the rectangular array setting, and the width of installation piece 18 is greater than the interval between two boards 15 that hinder, and then the accessible utilizes and hinders board 15 and carry on spacingly to installation piece 18.

Referring to fig. 8-10, a stopping plate 15 is fixedly connected to the rear side of a sliding slot 13 formed at the bottom end of the housing 1, wherein two stopping plates 15 are fixedly connected to the rear end surface of each sliding slot 13, a gap is formed between the two stopping plates 15, the gap between the two stopping plates 15 is larger than the diameter of a through circular hole formed in the mounting block 18, so that when a wire harness is inserted into the mounting block 18, the stopping plate 15 does not obstruct the wire harness, an anti-interference ring 21 is fixedly connected to the front end of the mounting block 18, the anti-interference ring 21 is of a spiral structure, the mounting block 18 is fixedly connected to the front end surface of the sliding slot 13 through the anti-interference ring 21, a pulling handle 22 is hinged to the bottom side of the mounting block 18, the anti-interference ring 21 of the spiral structure can perform anti-interference and anti-bending protection on the inserted wire harness, a magnetic ring 23 is further installed in the circular hole formed in the mounting block 18 through a return spring 24, the magnetic rings 23 are of a semi-annular structure, every two magnetic rings 23 which are installed in opposite directions form a group, two reset springs 24 are installed between each magnetic ring 23 and the inner wall of the hole in the installation block 18, the inner wall of each magnetic ring 23 is also fixedly connected with a limiting plate 25 in an arc array, the magnetic rings 23 of the arc structures can play a more comprehensive wrapping role on the inserted wire harness, the movement of the wire harness can be limited through the limiting plates 25, and the anti-interference capacity of the wire harness is further improved through the magnetic rings 23.

When in use: the cover plate 8 which is connected onto the shell 1 in a sliding mode through the guide block 9 can slide towards the rear side, when the cover plate 8 slides towards the rear side, the cover plate 8 can slide along the guide groove 6 formed in the shell 1 through the guide block 9, and further the cover plate 8 can slide more smoothly, when the cover plate 8 slides and unfolds, the external module can be externally connected onto the connecting block 2 arranged in the groove in the shell 1, after being inserted into the interface 3, the external module is connected with the optical frequency demodulator body in the shell 1 after being processed through the connecting block 2 for use, the external module can be wrapped in the shell 1 through the design, and the problem that the external module is easily bent due to collision due to the fact that the external module is inserted into the outer side of the shell 1 is effectively prevented;

a moisture-proof pad 10 is inserted into the inner side of the cover plate 8, and the presence of the moisture-proof pad 10 can protect the elements in the optical frequency demodulator main body inside the housing 1 from moisture and can also effectively protect the external module installed inside the housing 1.

Second embodiment

Based on the wireless optical frequency demodulator with the anti-interference structure provided by the first embodiment, the device realizes the high-efficiency protection work of the external module by means of the shell 1, the connecting block 2, the interface 3, the guide groove 6, the cover plate 8, the guide block 9 and the moisture-proof pad 10, but the problem that the normal operation of the device is affected by a large amount of dust deposition outside the device due to long-time storage cannot be solved in the practical application process, in order to solve the problem, the device is further provided with the air box 7, the heat dissipation fan 12, the air outlet 4, the air overflow opening 5, the cover plate 8, the guide block 9, the moisture-proof pad 10 and the air inlet 11, referring to fig. 4-7, the rear side of the bottom end face of the shell 1 is further fixedly connected with the baffle 16, the inside of the baffle 16 is provided with a linear array square groove, the length of the baffle 16 is matched with the maximum width of the groove of the chute 13, and then the wire harness can be partitioned and stored by the square groove arranged inside the baffle 16 when the wire harness is inserted, in order to reach more practical purpose, spacing groove 14 link up with spout 13 mutually, it inhales the hole to still be the rectangle array and seted up four magnetism on spout 13's preceding terminal surface, magnetism inhales hole and magnetism and inhale 19 phase-matchs, the equal fixedly connected with stopper 20 of both ends face central point position about installation piece 18, the round hole that link up is seted up to the inside of installation piece 18, it inhales 19 to still fixedly connected with four magnetism at the preceding terminal surface of installation piece 18, magnetism inhales 19 and is the rectangle array setting, the width of installation piece 18 is greater than the interval between two boards 15, and then the accessible utilizes board 15 to carry on spacingly to installation piece 18.

When the air-cooling fan is used, the heat-dissipating fan 12 arranged on the inner side of the air box 7 is started to rotate, when the heat-dissipating fan 12 rotates, external air flow can be introduced into the shell 1 through the air outlet 4 arranged in the shell 1, the air flow can also enter the inner side position of the cover plate 8 through the air inlet 11 arranged on the left side of the cover plate 8 synchronously, the upper side and the lower side of the cover plate 8 are both provided with heat-dissipating grooves, then after most of the air flow enters the cover plate 8, moisture contained in the introduced air flow can be filtered through the moisture-proof pad 10 inserted in the inner side of the cover plate 8, the filtered air enters the shell 1 to dissipate heat of an original piece in the shell and an external module arranged in the inner side of the interface 3, meanwhile, dust covered on the cover plate 8 can also drop, and then the heat-dissipating grooves arranged on the cover plate 8 and the air overflow port 5 arranged on the right side of the shell 1 are exhausted, to achieve a more practical purpose.

Third embodiment

Based on the wireless optical frequency demodulator with anti-interference structure provided by the second embodiment, it can realize the problem that the external part has a large amount of dust deposition to affect the normal operation of the device due to long-time storage by means of the air box 7, the heat dissipation fan 12, the air outlet 4, the air overflow port 5, the cover plate 8, the guide block 9, the moisture-proof pad 10 and the air inlet 11, but the anti-interference operation can not be completed while the connected wire harness is efficiently connected in practical application, in order to solve the above problem, the device is further provided with the chute 13, the limit groove 14, the baffle plate 15, the baffle plate 16, the inner groove 17, the mounting block 18, the magnetic absorption column 19, the limit block 20, the anti-interference ring 21, the handle 22, the magnetic ring 23, the reset spring 24 and the limit plate 25, referring to fig. 4-7, the baffle plate 16 is fixedly connected to the rear side of the bottom end face of the housing 1, the baffle plate 16 is provided with a square groove in a linear array, the length of baffle 16 and the biggest width phase-match of fluting of spout 13, and then the square groove of seting up inside accessible baffle 16 when the pencil inserts carries out the box to the pencil and accomodates, in order to reach more practical purpose, spacing groove 14 link up with spout 13 mutually, it has seted up four magnetism suction holes still to be rectangular array on the preceding terminal surface of spout 13, magnetism suction holes and magnetism suction column 19 phase-match, the equal fixedly connected with stopper 20 of both ends face central point position about installation piece 18, the round hole that link up is seted up to the inside of installation piece 18, it has four magnetism suction column 19 to go back fixedly connected with at the preceding terminal surface of installation piece 18, magnetism suction column 19 is the rectangular array setting, the width of installation piece 18 is greater than the interval between two resistance plates 15, and then the accessible utilizes resistance plate 15 to carry on spacingly to installation piece 18.

When the wire harness fixing device is used, an external wire harness is inserted into a round hole formed in the mounting block 18, after the wire harness is inserted, the inserted wire harness is automatically clamped and wrapped through the arc-shaped magnetic ring 23 elastically connected with the return spring 24 in the round hole, the limiting plates 25 are fixedly connected to the inner wall of the arc-shaped magnetic ring 23 in an arc array mode, and therefore after the wire harness is inserted into the inner side of the magnetic ring 23, efficient limiting operation can be conducted on the wire harness through the limiting plates 25, and anti-interference protection can also be conducted on the inserted wire harness through wrapping of the magnetic ring 23;

then, the handle 22 hinged on the outer side of the mounting block 18 is pulled to move towards the front side along the sliding groove 13 formed in the bottom side of the shell 1, when the mounting block 18 slides towards the front side along the inner groove 17 through the limiting block 20 fixedly connected with the outer side of the mounting block 18, the anti-interference ring 21 arranged between the mounting block 18 and the sliding groove 13 is extruded, and the spiral anti-interference ring 21 not only can perform efficient anti-interference operation on the inserted wire harness, but also can perform anti-bending operation on the inserted wire harness;

when the mounting block 18 moves forward and the magnetic attraction pole 19 and the magnetic attraction hole formed in the chute 13 are attracted, the handle 22 can be turned over along the mounting block 18, the handle 22 is clamped into the limiting groove 14, and the limiting operation of the inserted wire harness is completed, so that the purpose of being more practical is achieved.

The embodiments of the present invention have been presented for purposes of illustration and description, and are not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.

Claims

1. A wireless optical frequency demodulator with an anti-jamming structure, characterized by: comprises a shell (1); guide way (6) have been seted up to the inside of casing (1), and guide way (6) are used for assembling guide block (9), fixedly connected with bellows (7) are still gone back in the left side of casing (1), are the linear array in the inside of bellows (7) and install the fan, air outlet (4) have still been seted up on the inside left side of casing (1), and air outlet (4) and income wind gap (11) phase-match, and bellows (7) link up mutually with air outlet (4), and the inside of bellows (7) is the linear array and installs heat dissipation fan (12), the top sliding connection of casing (1) has apron (8).

2. The wireless-optical demodulator with interference rejection architecture as set forth in claim 1, wherein: apron (8) are inside hollow structure, and the top side and the bottom side of apron (8) all are linear array and have seted up the radiating groove, and income wind gap (11) have been seted up to the left end of apron (8), and the inside of apron (8) is pegged graft and is had dampproofing pad (10), and the bottom face fixedly connected with guide block (9) of apron (8), and guide block (9) are equipped with two altogether, and two guide block (9) are fixed connection respectively in the left and right sides of apron (8) bottom face front end.

3. The wireless-optical demodulator with interference rejection architecture as set forth in claim 1, wherein: the bottom side of the shell (1) is provided with a sliding groove (13), the sliding groove (13) is matched with the mounting block (18), the left side and the right side of the inside of each sliding groove (13) are provided with inner grooves (17), the inner grooves (17) are matched with the limiting blocks (20), the bottom end of the shell (1) is further provided with a limiting groove (14), and the limiting groove (14) is matched with the handle (22).

4. The wireless-optical demodulator with interference rejection architecture as set forth in claim 1, wherein: the magnetic suction type magnetic suction device is characterized in that a baffle (16) is fixedly connected to the rear side of the bottom end face of the shell (1), a square groove is formed in the baffle (16) in a linear array mode, the length of the baffle (16) is matched with the maximum width of the groove of the sliding groove (13), the limiting groove (14) is communicated with the sliding groove (13), four magnetic suction holes are formed in the front end face of the sliding groove (13) in a rectangular array mode, and the magnetic suction holes are matched with the magnetic suction columns (19).

5. The wireless-optical demodulator with interference rejection architecture as set forth in claim 3, wherein: the equal fixedly connected with stopper (20) of both ends face central point about installation piece (18) puts, and the round hole that link up is seted up to the inside of installation piece (18), and at the preceding terminal surface of installation piece (18) still fixedly connected with four magnetism posts (19), magnetism post (19) are the setting of rectangular array, and the width of installation piece (18) is greater than the interval between two resistance plates (15).

6. The wireless-optical demodulator with interference rejection architecture as set forth in claim 1, wherein: the rear side of spout (13) that the bottom of casing (1) was seted up still fixedly connected with hinders board (15), wherein rear end face fixedly connected with two department hinders board (15) of every department spout (13), the clearance has between two department hinders board (15), the clearance between two department hinders board (15) is greater than the diameter of the inside round hole of seting up of installation piece (18), the inside fixedly connected with connecting block (2) of casing (1), still be linear array in the inside of connecting block (2) and seted up interface (3), interface (3) are used for external module, excessive wind gap (5) have been seted up on the right side of casing (1).

7. The wireless-optical demodulator with interference rejection architecture as set forth in claim 5, wherein: the front end of the mounting block (18) is fixedly connected with an anti-interference ring (21), the anti-interference ring (21) is of a spiral structure, the mounting block (18) is fixedly connected with the front end face of the sliding groove (13) through the anti-interference ring (21), and a handle (22) is hinged to the bottom side of the mounting block (18).

8. The wireless-optical demodulator with interference rejection architecture as set forth in claim 5, wherein: the magnetic ring (23) is further mounted inside a circular hole formed in the mounting block (18) through a reset spring (24), the magnetic ring (23) is of a semi-annular structure, every two magnetic rings (23) which are oppositely mounted are in a group, two reset springs (24) are mounted between each magnetic ring (23) and the inner wall of the hole formed in the mounting block (18), and a limiting plate (25) is fixedly connected to the inner wall of each magnetic ring (23) in an arc array mode.