CN112097461A

CN112097461A - Box body rear cover and refrigerator

Info

Publication number: CN112097461A
Application number: CN202011103808.4A
Authority: CN
Inventors: 程春明; 李�杰; 张新星
Original assignee: Changhong Meiling Co Ltd
Current assignee: Changhong Meiling Co Ltd
Priority date: 2020-10-15
Filing date: 2020-10-15
Publication date: 2020-12-18

Abstract

The invention discloses a box body rear cover and a refrigerator, and relates to the technical field of refrigerators. The invention comprises a rear cover body; the rear cover body comprises a clamping part, a heat dissipation part and a device installation part; the clamping and matching part comprises a matching body and a clamping and matching body; the matching body comprises a first outer matching surface, a peripheral matching surface, a second outer matching surface and an inner matching surface; the buckle body is arranged on the inner matching surface; the buckle body is of an extending body structure and comprises an upper buckle matching surface, a lower buckle matching surface, an inner side buckle matching surface and an outer buckle matching surface; the heat dissipation part comprises an air inlet system and an air outlet system; air outlets are symmetrically arranged on two sides of the rear cover body; the air inlet system comprises an air inlet, a dust screen and a dust cover. According to the invention, the clamping part, the heat dissipation part and the device installation part are arranged on the rear cover body, so that the problem that the heat of the heat exchange module is difficult to be discharged out of the box by the conventional box body rear cover is solved.

Description

Box body rear cover and refrigerator

Technical Field

The invention belongs to the technical field of refrigerators, and particularly relates to a refrigerator body rear cover and a refrigerator.

Background

The small refrigerator is more and more popular with users who are alone or frequently moved because of its portability, convenient to transport and carry, and also gradually becomes basic configuration such as hotel, rental room, and the like. The application scenes of the small refrigerator are diversified, the diversification of user groups is realized, and the diversified requirements such as the function requirement, the appearance requirement, the color requirement, the appearance size and the personalized requirement of the small refrigerator are more and more prominent.

At present, a large number of manufacturers for producing small-volume refrigerators in the market have single functions, appearance models, color matching and the like, and are lack of individuation, and the requirements on the space layout, the structural design and the like of product parts are high mainly due to the small overall size of the small-volume refrigerator. Because the whole volume is not large, a semiconductor direct refrigeration mode is basically adopted. In view of the fact that both the appearance and the refrigeration mode are single, most small refrigerators basically have no rear cover, or the used rear cover is single in structure, and devices such as a control board are installed inside the small refrigerators, so that other functional requirements are not needed.

Aiming at the air-cooled semiconductor refrigerator, how to discharge the heat of the heat exchange module out of the refrigerator through the rear cover of the refrigerator body, and no related design scheme exists in the interior of the industry.

Disclosure of Invention

The invention aims to provide a box body rear cover and a refrigerator.

In order to solve the technical problems, the invention is realized by the following technical scheme:

the invention relates to a box body rear cover, which comprises a rear cover body; the rear cover body comprises a clamping part, a heat dissipation part and a device installation part; the clamping and matching part comprises a matching body and a clamping and matching body; the matching body comprises a first outer matching surface, a peripheral matching surface, a second outer matching surface and an inner matching surface;

the buckle body is arranged on the inner side matching surface; the buckle body is of an extending body structure and comprises an upper buckle matching surface, a lower buckle matching surface, an inner side buckle matching surface and an outer buckle matching surface; the heat dissipation part comprises an air inlet system and an air outlet system; air outlets are symmetrically arranged on two sides of the rear cover body.

Furthermore, the end part of the matching surface of the outer buckle is provided with an inclined surface, so that the outer buckle is convenient to insert and assemble with an outer barrel of the box body; the root of the buckle body is provided with a reinforcing rib.

Furthermore, the air inlet system comprises an air inlet, a dust screen and a dust cover;

the air inlet is of a sinking platform structure and comprises a first step surface, a first circumferential surface, a second step surface and a second circumferential surface.

Furthermore, the dust screen is made of a soft material with a micropore structure; the upper end of the dustproof net is provided with a first avoidance groove and a second avoidance groove which are used for avoiding a pair of extending blocks; a third avoidance groove is formed in the lower end of the dustproof net and used for avoiding the handle structure; the dust cover is arranged between the dust cover and the air inlet; the dustproof cover comprises a dustproof cover inner side surface and a dustproof cover circumferential surface; the inner surface of the dustproof cover is fixedly connected with a pair of extending blocks; the lower end of the inner surface of the dustproof cover is provided with a handle structure.

Furthermore, a plurality of vent holes are formed in the outer surface of the dustproof cover; the extending block comprises an extending block limiting surface and a front end inclined surface; the whole buckle structure is a U-shaped elastic body; the bottom of the handle structure is provided with a U-shaped opening; the root parts at two sides of the U-shaped opening are provided with convex ribs; a plurality of through holes are formed in the inner surface of the second step surface; a pair of U-shaped holes are symmetrically formed in the upper part of the second step surface; the lower part of the 121132 is provided with a square opening.

Furthermore, the pair of U-shaped holes are symmetrically distributed on two sides of the second step surface and are led into the U-shaped holes through the limiting surfaces of the extending blocks; the air inlet comprises an inner side surface of the air inlet; the front end inclined plane is matched with the inner side surface of the air inlet.

Furthermore, the square-shaped opening is matched with the buckle handle structure; the air outlet system is arranged on two sides of the rear cover body and corresponds to the radiating fins in position; the device mounting part comprises a control panel, an indicator light, a temperature sensor, a control panel mounting part, an indicator light mounting part and a sensor mounting part; the surface of the control panel is provided with a control panel mounting hole; a charging interface is arranged on the control panel; the control panel mounting part is arranged on the inner side matching surface; the control panel mounting part comprises four mounting seats; the mounting seat is of a cylindrical structure, and a mounting hole is formed in the inner wall of the mounting seat; the inner wall of the mounting hole is matched with the mounting hole of the control panel; the side surfaces of the mounting seat are fixedly connected with a plurality of reinforcing ribs.

Furthermore, limit rib structures are distributed on the circumferential opposite angles of the mounting seat and used for positioning when the mounting seat is preassembled with the control panel; the mounting seat is provided with a mounting seat through hole; a box-shaped bearing seat is arranged below the indicator lamp mounting part; a through hole of the bearing seat is formed in one side of the box-shaped bearing seat, and light of the indicator lamp is projected through the through hole of the bearing seat; the box-shaped bearing seat comprises an inner side of the bearing seat and a bearing seat protrusion.

Furthermore, the indicator light comprises a main body side surface and an indicator light limiting surface; the sensor mount includes a niche structure; the bottom of the niche platform structure is provided with a plurality of communicating holes, so that the temperature sensor can conveniently detect the ambient temperature.

A refrigerator comprises a box body rear cover; the box body rear cover is clamped in the refrigerator body; the refrigerator body comprises a refrigerator body outer barrel and a refrigerator body heat dissipation module; a fan and radiating fins are arranged in the box body radiating module; the air inlet system and the air outlet system are respectively matched with the box body heat dissipation module to form an air path circulation system; the back of the outer barrel of the box body is provided with a sinking step surface and a sinking platform limiting surface;

the outer barrel of the box body comprises an outer barrel back surface positioned on the back of the outer barrel of the box body; the back surface of the outer barrel is flush with the first outer matching surface of the matching body, so that the integral feeling is kept; a plurality of through hole structures are distributed at the axial positions of the sinking step surfaces, and the inner walls of the through hole structures are matched with the buckling bodies; the through hole structure comprises an upper inner wall of the through hole, a lower inner wall of the through hole, a first through hole matching surface and a second through hole matching surface; the through hole structure is evenly distributed with blocky structures around, before the foaming material is filled, the through hole structure is sealed by an adhesive tape, no foam liquid enters, and the later-stage buckle body can be conveniently and smoothly inserted.

The invention has the following beneficial effects:

1. according to the refrigerator body rear cover, the refrigerator body rear cover is assembled with the refrigerator body in a clamping mode, the screw-free green design is basically achieved, materials are saved, auxiliary tool equipment is reduced, the assembling process is simple, and the production efficiency is improved. Overall structure is compact, and is multiple functional, promotes user experience and feels.

2. The control panel, the indicator lamp and the temperature sensor are arranged in the rear cover of the refrigerator body, so that the performance control of the refrigerator is realized; the heat dissipation function of the refrigerator body is realized through the air inlet system and the air outlet system which are arranged on the rear cover of the refrigerator body.

3. The dust cover is arranged between the dust cover and the air inlet, so that dirt is prevented from entering the rear cover body through the air inlet; when the user need change or wash the dust screen, can support the U type elastomer of the attacker structure of shield with the stereoplasm stock, utilize its elasticity, make U type trompil break away from the air intake medial surface, then take out the shield, it is clean convenient.

Of course, it is not necessary for any product in which the invention is practiced to achieve all of the above-described advantages at the same time.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a rear cover of a box body according to the present invention;

FIG. 2 is a schematic structural view of a refrigerator body;

FIG. 3 is a front view of FIG. 1;

FIG. 4 is a schematic cross-sectional view taken along line A-A of FIG. 3;

FIG. 5 is a schematic view of the mounting of the snap-fit portion and the heat sink portion;

FIG. 6 is a front view of FIG. 5;

FIG. 7 is a schematic cross-sectional view taken at C-C in FIG. 6;

FIG. 8 is an enlarged partial view of FIG. 7 at D;

FIG. 9 is an enlarged view of a portion of FIG. 7 at E;

FIG. 10 is a schematic cross-sectional view taken along line B-B of FIG. 6;

FIG. 11 is an enlarged partial schematic view at F of FIG. 10;

FIG. 12 is a schematic structural view of the fastener;

FIG. 13 is a front view of the refrigerator cabinet;

FIG. 14 is a schematic sectional view taken at G-G in FIG. 13;

FIG. 15 is a schematic sectional view taken at H-H in FIG. 13;

fig. 16 is an exploded view of the back case body.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-2, the present invention is a box body rear cover, which comprises a rear cover body 1; the rear cover body 1 includes a snap-fit portion 11, a heat dissipation portion 12, and a component mounting portion 13; a functional device is mounted in the device mounting portion 13; the snap-fit part 11 comprises a fitting body 111 and a buckling body 112; the fitting body 111 is located at the peripheral edge portion of the rear cover body 1; the mating body 111 comprises a first outer mating surface 1110, a peripheral mating surface 1111, a second outer mating surface 1112 and an inner mating surface 1113; the peripheral mating surface 1111 is an inclined structure;

the buckle body 112 is arranged on the inner matching surface 1113; the buckle body 112 is an extended body structure, and the buckle body 112 includes an upper buckle mating surface 1121, a lower buckle mating surface 1122, an inner buckle mating surface 1123, and an outer buckle mating surface 1124; the heat dissipation part 12 comprises an air inlet system 121 and an air outlet system 122; the air inlet system 121 is arranged at a position corresponding to the fan 221; air outlets 1221 are symmetrically arranged at two sides of the rear cover body 1; the air outlet 1221 includes a plurality of air outlets 12211, which is convenient for guiding heat out of the box.

Preferably, the end of the outer snap fitting surface 1124 is provided with an inclined surface 11241 for facilitating insertion and assembly with the outer tub 21 of the cabinet; the base of the buckle body 112 is provided with a rib 1125.

Preferably, the air inlet system 121 includes an air inlet 1211, a dust screen 1212 and a dust cover 1213, when the user needs to replace or clean the dust screen 1212, the user can use a hard long rod to abut against the U-shaped elastic body of the fastener structure 12133 of the dust cover 1213, and use its elasticity to separate the U-shaped opening 121331 from the inner side surface 12115 of the air inlet, and then remove the dust cover 1213; the intake opening 1211 is of a sunken-platform structure, and the intake opening 1211 includes a first step surface 12111, a first circumferential surface 12112, a second step surface 12113, and a second circumferential surface 12114.

Preferably, the dust screen 1212 is a soft material with a microporous structure; the upper end of the dustproof net 1212 is provided with a first avoidance groove 12121 and a second avoidance groove 12122 for avoiding a pair of protruding blocks 12132; a third avoiding groove 12123 is formed at the lower end of the dustproof net 1212 and is used for avoiding the handle structure 12133; the dust cover 1213 is arranged between the dust cover 1213 and the air inlet 1211 to prevent dirt from entering the interior of the rear cover body 1 through the air inlet; the dust cover 1213 includes a dust cover inner side surface 12130 and a dust cover circumferential surface 12134; the dust cover inner side surface 12130 is fitted with the first step surface 12111; the dust cover circumferential surface 12134 mates with the first circumferential surface 12112; a pair of extending blocks 12132 is fixedly connected to the inner surface of the dust cover 1213; the lower end of the inner surface of the dust cover 1213 is provided with a fastener structure 12133.

Preferably, the outer surface of the dust cover 1213 is provided with a plurality of vent holes 12131; the protruding block 12132 comprises a protruding block limiting surface 121321 and a front end inclined surface 121322; the handle structure 12133 is a U-shaped elastomer; the bottom of the handle structure 12133 is provided with a U-shaped opening 121331; the root parts of the two sides of the U-shaped opening 121331 are provided with convex ribs 121332; a plurality of through holes 121131 are formed on the inner surface of the second step surface 12113; a pair of U-shaped holes 121132 are symmetrically arranged at the upper part of the second step surface 12113; 121132 is provided with a square opening 121133.

Preferably, a pair of U-shaped holes 121132 are symmetrically distributed on both sides of the second step surface 12113, and are guided into the U-shaped holes 121132 through the limiting surface 121321 of the protruding block 12132; the air inlet 1211 includes an air inlet inner side surface 12115; the front end chamfer 121322 mates with the intake inlet interior side 12115.

Preferably, the square-shaped opening 121133 mates with the catch structure 12133; the air outlet system 122 is arranged on two sides of the rear cover body 1 and corresponds to the radiating fins 223 in position; the component mounting part 13 includes a control board 3, an indicator lamp 4, a temperature sensor 5, a control board mounting part 131, an indicator lamp mounting part 132, and a sensor mounting part 133; the surface of the control panel 3 is provided with a control panel mounting hole 31; a charging interface 32 is arranged on the control panel 3; the control panel mounting portion 131 is provided on the inside mating surface 1113; the control panel mounting portion 131 includes four mounting sockets 1311; the mounting seat 1311 is of a cylindrical structure, and a mounting hole 13111 is formed in the inner wall of the mounting seat 1311; the inner wall of the mounting hole 13111 is matched with the control panel mounting hole 31; a plurality of reinforcing ribs 13112 are fixedly connected to the peripheral side surface of the mounting seat 1311.

Preferably, the mounting seat 1311 is circumferentially and diagonally distributed with a limiting rib structure 13113 for positioning when being preassembled with the control board 3; the mounting seat 1311 is provided with a mounting seat through hole 1312; the mount through hole 1312 is assembled with the charging interface 32; the indicator lamp mounting part 132 is positioned at the bottom of the rear cover body 1; the indicator lamp mounting part 132 is a through hole structure; a box-shaped receiving seat 1321 is arranged below the indicator lamp mounting part 132; a bearing seat through hole 13211 is formed in one side of the box-shaped bearing seat 1321, and light of the indicator lamp 4 is projected through the bearing seat through hole 13211; the box-like socket 1321 includes a socket inner side 13212 and a socket protrusion 13213.

Preferably, the indicator light 4 comprises a main body side surface 41 and an indicator light limiting surface 42; the indicator lamp 4 is a square light guide body; the indicator light limiting surface 42 is matched with the bearing seat protrusion 13213; the sensor mounting part 133 is provided at the bottom of the rear cover body 1; the sensor mounting portion 133 includes a niche structure 1331 for facilitating insertion of the temperature sensor 5 after being wrapped with a flexible material; the bottom of the niche platform structure 1331 is provided with a plurality of communicating holes 13111 for the temperature sensor 5 to detect the ambient temperature.

A refrigerator includes a cabinet rear cover; the box body rear cover is clamped in the refrigerator body 2; the refrigerator body 2 comprises a body outer barrel 21 and a body heat radiation module 22; a fan 221 and a radiating fin 223 are arranged in the box body radiating module 22; the outer barrel 21 of the box body is fixed with the clamping part 11 of the rear cover body 1 through clamping connection; the box body heat dissipation module 22 is matched with the heat dissipation part 12; the air inlet system 121 and the air outlet system 122 are respectively matched with the box body heat dissipation module 22 to form an air path circulation system; the back of the outer barrel 21 of the box body is provided with a sinking step surface 211 and a sinking platform limiting surface 212, the sinking step surface 211 is matched with the inner side matching surface 1113, and the sinking platform limiting surface 212 is matched with the peripheral matching surface 1111;

the cabinet tub 21 includes a tub back surface 210 on the back of the cabinet tub 21; the tub back 210 is flush with the first outer mating surface 1110 of the mating body 111, so as to maintain the integrity; a plurality of through hole structures 213 are distributed at the axial position of the sinking step surface 211, and the inner walls of the through hole structures 213 are matched with the buckle body 112; the through hole structure 213 includes a through hole upper inner wall 2131, a through hole lower inner wall 2132, a first through hole mating surface 2133 and a second through hole mating surface 2134; the through hole upper inner wall 2131 is matched with the upper buckle matching surface 1121; the through hole lower inner wall 2132 is matched with the lower buckle matching surface 1122; the first through hole mating surface 2133 is matched with the inner side buckle mating surface 1123; the second through hole mating surface 2134 mates with the outer snap mating surface 1124; blocky structures 2135 are uniformly distributed around the through hole structure 213, and before the foaming material is filled, the through hole structure is sealed by an adhesive tape without entering foam liquid, so that the buckle body 112 can be inserted smoothly at a later stage.

The installation method of the refrigerator rear cover 1 comprises the following steps: the related electric device is mounted on the device mounting portion 13, the dust screen 1212 is placed on the second step surface 12113 of the air inlet 1211, then the dust screen 1212 is pressed by the dust cover 1213, and further, two protruding blocks 12132 of the dust cover 1213 are inserted, a pair of U-shaped holes 121132 symmetrically arranged on the second step surface 12113 is pressed by force, and the U-shaped elastic body of the bottom clasp structure 12133 is limited by the U-shaped opening 121331. After the assembly of the rear cover assembly, the fastening body 112 is inserted into the through hole structure 213 for assembly, so that the mating body 111 is consistent with the outer tub back 210.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily 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.

The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best understand the invention for and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A box body rear cover comprises a rear cover body (1); the method is characterized in that:

the rear cover body (1) comprises a clamping part (11), a heat dissipation part (12) and a device installation part (13);

the clamping and matching part (11) comprises a matching body (111) and a buckling body (112); the matching body (111) comprises a first outer matching surface (1110), a peripheral matching surface (1111), a second outer matching surface (1112) and an inner matching surface (1113);

the buckle body (112) is arranged on the inner matching surface (1113); the buckle body (112) is an extension body structure, and the buckle body (112) comprises an upper buckle matching surface (1121), a lower buckle matching surface (1122), an inner buckle matching surface (1123) and an outer buckle matching surface (1124);

the heat dissipation part (12) comprises an air inlet system (121) and an air outlet system (122);

air outlets (1221) are symmetrically arranged on two sides of the rear cover body (1).

2. The box body rear cover according to claim 1, wherein the end of the outer snap fitting surface (1124) is provided with an inclined surface (11241); the root of the buckle body (112) is provided with a reinforcing rib (1125).

3. A box back cover according to claim 1 or 2, wherein the air intake system (121) comprises an air intake (1211), a dust screen (1212) and a dust cover (1213);

the air inlet (1211) is of a sunken platform structure, and the air inlet (1211) comprises a first step surface (12111), a first circumferential surface (12112), a second step surface (12113) and a second circumferential surface (12114).

4. A box back cover according to claim 3, wherein the dust screen (1212) is a soft material with a micro-porous structure; a first avoidance groove (12121) and a second avoidance groove (12122) are formed in the upper end of the dustproof net (1212); the lower end of the dustproof net (1212) is provided with a third avoidance groove (12123);

the dust cover (1213) is arranged between the dust cover (1213) and the air inlet (1211); the dust cover (1213) includes a dust cover inner side surface (12130) and a dust cover circumferential surface (12134); a pair of extending blocks (12132) is fixedly connected with the inner surface of the dustproof cover (1213); the lower end of the inner surface of the dustproof cover (1213) is provided with a buckle structure (12133).

5. The box body rear cover according to claim 4, characterized in that the outer surface of the dust cover (1213) is provided with a plurality of vent holes (12131); the extending block (12132) comprises an extending block limiting surface (121321) and a front end inclined surface (121322);

the handle structure (12133) is a U-shaped elastomer; the bottom of the buckle handle structure (12133) is provided with a U-shaped opening (121331); the root parts of the two sides of the U-shaped opening (121331) are provided with convex ribs (121332);

a plurality of through holes (121131) are formed in the inner surface of the second step surface (12113); a pair of U-shaped holes (121132) are symmetrically formed in the upper part of the second step surface (12113); the lower part of the 121132 is provided with a square opening (121133).

6. A box back cover according to claim 5, characterized in that a pair of said U-shaped holes (121132) are symmetrically distributed on both sides of the second step surface (12113);

the air intake (1211) includes an air intake inner side surface (12115); the front end inclined plane (121322) is matched with the inner side surface (12115) of the air inlet.

7. A cabinet back cover according to claim 5 or 6, wherein the square-shaped opening (121133) is engaged with a handle structure (12133);

the device mounting part (13) comprises a control board (3), an indicator light (4), a temperature sensor (5), a control board mounting part (131), an indicator light mounting part (132) and a sensor mounting part (133); a charging interface (32) is arranged on the control panel (3); the control panel mounting part (131) is arranged on the inner matching surface (1113); the control panel mounting part (131) comprises four mounting seats (1311); the mounting seat (1311) is of a cylindrical structure, and a mounting hole (13111) is formed in the inner wall of the mounting seat (1311); the peripheral side surface of the mounting seat (1311) is fixedly connected with a plurality of reinforcing ribs (13112).

8. The box body rear cover as claimed in claim 7, characterized in that the mounting seat (1311) is circumferentially and diagonally distributed with a limit rib structure (13113); the mounting seat (1311) is provided with a mounting seat through hole (1312);

a box-shaped bearing seat (1321) is arranged below the indicator lamp mounting part (132); a bearing seat through hole (13211) is formed in one side of the box-shaped bearing seat (1321); the box-shaped socket (1321) includes a socket inner side (13212) and a socket protrusion (13213).

9. A box back cover according to claim 7, characterized in that the indicator light (4) comprises a main body side surface (41) and an indicator light limiting surface (42);

the sensor mounting portion (133) includes a niche structure (1331); the bottom of the niche platform structure (1331) is provided with a plurality of communicating holes (13111).

10. A refrigerator comprising a cabinet back cover according to any one of claims 1 to 9; the box body rear cover is clamped in the refrigerator body (2);

the refrigerator body (2) comprises a body outer barrel (21) and a body heat radiation module (22); a fan (221) and cooling fins (223) are arranged in the box body heat dissipation module (22); the air inlet system (121) and the air outlet system (122) are respectively matched with the box body heat dissipation module (22) to form an air path circulation system;

the back of the outer barrel (21) of the box body is provided with a sinking step surface (211) and a sinking platform limiting surface (212);

the box body outer barrel (21) comprises an outer barrel back surface (210) positioned at the back of the box body outer barrel (21); the outer barrel back surface (210) is flush with a first outer matching surface (1110) of the matching body (111); a plurality of through hole structures (213) are distributed at the axial position of the sinking step surface (211);

the through hole structure (213) comprises a through hole upper inner wall (2131), a through hole lower inner wall (2132), a first through hole matching surface (2133) and a second through hole matching surface (2134); block-shaped structures (2135) are uniformly distributed on the periphery of the through hole structure (213).