Water purifier capable of rotationally unlocking filter element

Abstract

The utility model relates to a water purifier with a rotary unlocking filter element. The technical problem that an existing filter element is low in replacement efficiency is solved. The water purifier is arranged in a telescopic track and comprises a water purifier shell, a filter element mounting frame is arranged in the water purifier shell, a filter element mounting cavity is formed in the filter element mounting frame, a filter element body is arranged in the filter element mounting cavity, and the lower end of the filter element body is provided with a filter element connector which is connected with a water inlet connector located in the lower end of the filter element mounting frame in an inserted mode and connected with the water inlet connector in a circumferential positioning mode. A rotary positioning seat is arranged at the upper end of the filter element body, a positioning groove is formed in the circumferential outer side of the rotary positioning seat, a mounting seat is arranged at the upper end of the filter element mounting frame, and a positioning block capable of being movably arranged in the radial direction of the rotary positioning seat is arranged in the mounting seat through an elastic movable mounting structure. The device has the advantages that the rotary positioning seat and the filter element mounting rack can be connected in an inserted manner through the positioning groove and the positioning block, and the connecting effect of the filter element mounting rack and the filter element body can be ensured. And the elastic jacking assembly can push the positioning block, so that the inserting effect between the positioning block and the positioning groove is ensured.

Description

TECHNICAL FIELD

[0001] The utility model belongs to water purifier equipment technical field, concretely relates to a water purifier of rotating unlocking filter core. BACKGROUND

[0002] At present, most of the existing water purifiers filter water quality through filter core, and in order to ensure the filter effect of filter core on water quality in long-term use, the filter core needs to be replaced regularly, but the existing filter core is mostly installed and fixed through threaded connection or buckle connection, wherein the threaded connection needs to be locked by tool, which affects the replacement efficiency of filter core, and the buckle connection needs to overcome large friction to lock or disassemble the filter core, which affects the user experience and the replacement efficiency of filter core.

[0003] In order to solve the problems in the prior art, people have carried out long-term exploration and proposed various solutions. For example, the Chinese patent document discloses a water purifier filter core quick release structure and water purifier [202310394207.0], which comprises a support frame and a sleeve shell mounted on the support frame, the first end of the support frame is provided with an elastic locking structure, the filter core can be inserted into the sleeve shell, and the first end of the filter core is provided with a locking part and an unlocking part corresponding to the elastic locking structure.

[0004] The above-mentioned scheme solves the problem of low replacement efficiency of the existing filter core to some extent, but the scheme still has many deficiencies, for example, the locking mechanism of the filter core is locked by the locking part at the bottom of the filter core and the locking block at the bottom of the sleeve shell, which is not convenient to replace and maintain in long-term use, affects the service life, and the handle drives the filter core to rotate, the handle is easy to be damaged in long-term use, and the installation and removal efficiency of the filter core is affected. SUMMARY

[0005] The utility model aims at the above problem, provides a water purifier of rotating unlocking filter core.

[0006] In order to achieve the above object, the utility model discloses the following technical scheme: a kind of water purifier of rotating unlocking filter core, including water purifier shell, the water purifier shell is equipped with filter core mounting frame, the filter core mounting frame is equipped with at least one filter core mounting cavity, the filter core mounting cavity is equipped with filter core body, the lower end of the filter core body has with the water inlet interface plug-in and the circumferential positioning connection of being located the filter core mounting frame lower end, the upper end of the filter core body is equipped with with the circumferential rotation of the rotating positioning seat of filter core body, rotating positioning seat circumferential outside is equipped with at least one radially inward recessed positioning groove, the upper end of the filter core mounting frame is equipped with at least one installation seat located rotating positioning seat circumferential outside, the installation seat is equipped with with the positioning block that can be radially active arrangement and is clamped in positioning groove by elastic active installation structure along rotating positioning seat, rotating positioning seat can drive positioning groove to rotate, and when rotating positioning seat in rotation process, positioning groove and installation seat are correspondingly arranged and positioning block is inserted in positioning groove, can make filter core body and filter core mounting frame between plug-in connection, guarantee the installation effect of filter core body, and when rotating positioning seat rotates, positioning block is compressed and separated from positioning groove by elastic active installation structure, complete the disassembly of filter core body, guarantee the disassembly efficiency of filter core body.

[0007] In the above-mentioned water purifier of rotating unlocking filter core, the number of the positioning groove is two and symmetrically arranged on both sides of the rotating positioning seat, the rotating positioning seat and the filter core body are in the shape-matched cylindrical structure and coaxially rotate connected, the rotating positioning seat has an inwardly recessed groove on the upper end, the rotating handle is integrally formed in the groove and outwardly protrudes and matches the shape of the groove, one end of the rotating handle is larger in diameter than the other end, and the two ends of the rotating handle have arc-shaped parts respectively, the groove can facilitate the user to hold the rotating handle, and the arc-shaped parts can increase the size of the rotating handle for easy user control.

[0008] In the above-mentioned water purifier of rotating unlocking filter core, the number of the installation seat is two and symmetrically arranged on both sides of the rotating positioning seat, and the positioning blocks in the installation seat are one-to-one correspondingly arranged with the positioning grooves, the two installation seats and the positioning blocks can ensure the connection stability between the filter core mounting frame and the filter core body.

[0009] In the water purifier with a rotating unlocking filter element, the elastic movable mounting structure comprises an arc-shaped recess provided on the mounting base near one end of the rotating positioning base and matched with the outer side of the rotating positioning base, an installation channel is arranged in the arc-shaped recess and extends along the radial direction of the rotating positioning base, one end of the positioning block is arranged in the installation channel through the guide assembly and the other end of the positioning block is exposed from the installation channel, and the elastic pressing assembly is arranged between the positioning block and the mounting base, the arc-shaped recess can be matched with the side edge of the rotating positioning base, the installation channel can facilitate the installation and placement of the positioning block, the elastic pressing assembly can drive the positioning block to extend, the guide assembly can limit the positioning block, the displacement of the positioning block towards the rotating positioning base is ensured, and the insertion effect is ensured.

[0010] In the water purifier with a rotating unlocking filter element, the guide assembly comprises a plurality of guide ribs arranged on the inner bottom of the installation channel and extending along the axial direction of the installation channel, and the guide ribs are respectively in contact with the bottom of the positioning block. The guide ribs can guide the positioning block, so that the positioning block can stably move towards the rotating positioning base.

[0011] In the water purifier with a rotating unlocking filter element, the installation channel penetrates one end of the mounting base away from the arc-shaped recess, and the mounting base is provided with a insertion slot connected with the installation channel, and the insertion plate extending into the installation channel is inserted into the insertion slot. The insertion slot can facilitate the placement of the insertion plate, and the insertion plate can close the opening of one end of the installation channel, so that the positioning block can only move towards the other opening.

[0012] In the water purifier with a rotating unlocking filter element, the elastic pressing assembly comprises a pressing spring arranged in the installation channel, one end of the pressing spring acts on the spring mounting hole in one end of the positioning block, and the other end of the pressing spring acts on the insertion plate. The spring mounting hole connects the positioning block and the pressing spring, when the rotating positioning base rotates, the positioning block extends inward and the pressing spring is compressed, when the positioning block is arranged corresponding to the positioning groove, the pressing spring drives the positioning block to move towards the positioning groove, and the insertion effect between the positioning block and the positioning groove is ensured.

[0013] In the water purifier with a rotating unlocking filter element, the opening size of one end of the installation channel near the arc-shaped recess is smaller than that of the other end, and the positioning block has a limiting portion on both sides of one end in the installation channel, which abuts against the inner side of the opening of one end of the installation channel near the arc-shaped recess. The limiting portion can limit the displacement distance of the positioning block, effectively prevent the positioning block from separating from the installation channel, and ensure the installation effect of the positioning block.

[0014] In the water purifier of the above-mentioned rotating and unlocking filter element, the positioning groove is arc-shaped, the depth of the middle part of the positioning groove gradually decreases to the depth of the two ends, and the one end of the positioning block exposed from the mounting channel has a positioning part matched with the positioning groove, so that the clamping effect between the positioning part and the positioning groove is improved, and the stability of the plug-in connection between the filter element body and the filter element mounting frame is ensured.

[0015] In the water purifier of the above-mentioned rotating and unlocking filter element, the rotating positioning seat is closed at the upper end and open at the lower end, the lower end of the rotating positioning seat abuts against the upper end surface of the filter element body, the first cylindrical body is coaxially arranged on the circumferential inner side of the lower end of the rotating positioning seat, the second cylindrical body is coaxially arranged on the upper end of the filter element body and located on the circumferential inner side of the first cylindrical body, the lower end of the first cylindrical body has the first limiting part bent inward in the circumferential direction, and the upper end of the second cylindrical body has the second limiting part bent outward and axially limited and contacted with the first limiting part, so that the rotating positioning seat and the filter element body are conveniently positioned and placed through the first cylindrical body and the second cylindrical body, the first cylindrical body and the second cylindrical body are connected through the first limiting part and the second limiting part, the connection stability between the filter element body and the filter element mounting frame is ensured, and the connection effect of the filter element mounting frame and the filter element body is ensured.

[0016] Compared with the prior art, the water purifier has the following advantages:

[0017] 1. The first limiting part of the first cylindrical body and the second limiting part of the second cylindrical body can ensure the connection stability between the rotating positioning seat and the filter element body.

[0018] 2. The rotating positioning seat and the filter element mounting frame are connected through the plug-in connection of the positioning groove and the positioning block, and the connection effect of the filter element mounting frame and the filter element body is ensured.

[0019] 3. When the rotating positioning seat rotates, the positioning block is compressed through the pressing spring, and when the positioning groove corresponds to the positioning block, the pressing spring drives the positioning block to be inserted into the positioning groove, so that the plug-in effect between the positioning block and the positioning groove is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a structural schematic view of the utility model.

[0021] Figure 2 is a structural schematic view of the filter element mounting frame in the utility model.

[0022] Figure 3 is a structural sectional view of the filter element mounting frame in the utility model.

[0023] Figure 4 is an exploded view of the elastic pressing assembly in the utility model.

[0024] Figure 5 is a structure diagram of the rotating positioning seat in the utility model.

[0025] In the drawing: the water purifier shell 1, the filter core mounting frame 2, the filter core mounting cavity 21, the water inlet interface 22, the mounting seat 23, the slot 231, the plugboard 232, the filter core body 3, the filter core interface 31, the second cylindrical body 32, the second limiting part 321, the rotating positioning seat 4, the positioning groove 41, the recess 42, the rotating handle 43, the arc-shaped part 44, the first cylindrical body 45, the first limiting part 451, the elastic movable mounting structure 5, the arc-shaped recessed part 51, the mounting channel 52, the positioning block 6, the limiting part 61, the positioning part 62, the guide assembly 7, the guide rib 71, the elastic pressing assembly 8, the pressing spring 81, the spring mounting hole 82. DETAILED DESCRIPTION

[0026] The utility model will be made further detailed explanation in combination with the specific implementation and the drawing.

[0027] As Figure 1 , Figure 2 , Figure 3 , Figure 5 Indicated, this kind of rotating unlocking filter core's water purifier, including water purifier shell 1, be equipped with filter core mounting frame 2 in water purifier shell 1, be equipped with at least one filter core mounting cavity 21 in filter core mounting frame 2, be equipped with filter core body 3 in filter core mounting cavity 21, through filter core mounting cavity 21, it can be convenient to position the placement of filter core body 3, filter core body 3 lower end has with the water inlet interface 22 of the lower end of filter core mounting frame 2 plug-in and the circumferential positioning connection of filter core interface 31, through water inlet interface 22 and filter core interface 31, it can guarantee the plug-in effect between filter core body 3 and filter core mounting frame 2, guarantee the use effect of filter core body 3, filter core body 3 upper end is equipped with rotating positioning seat 4, which is circumferentially rotatably arranged with filter core body 3, rotating positioning seat 4 circumferential outside is equipped with at least one radial recess positioning groove 41, filter core mounting frame 2 upper end is equipped with at least one mounting seat 23 located rotating positioning seat 4 circumferential outside, the positioning block 6 that can be radially movablely arranged in rotating positioning seat 4 and is clamped in positioning groove 41 is equipped with in mounting seat 23 through elastic movable mounting structure 5, rotating positioning seat 4 can drive positioning groove 41 to rotate, and when rotating positioning seat 4 is in the rotating process, positioning groove 41 is correspondingly arranged with mounting seat 23 and positioning block 6 is plug-in arranged in positioning groove 41, can make filter core body 3 and filter core mounting frame 2 are connected by plug-in, guarantee the installation effect of filter core body 3, and when rotating positioning seat 4 rotates, positioning block 6 is compressed and separated from positioning groove 41 through elastic movable mounting structure 5, complete the disassembly of filter core body 3, guarantee the disassembly efficiency of filter core body 3.

[0028] Specifically, the positioning groove 41 is two in number and symmetrically arranged on both sides of the rotating positioning seat 4, the rotating positioning seat 4 has a cylindrical structure matching the shape of the filter core body 3 and is coaxially connected with the filter core body 3, the rotating positioning seat 4 has an inwardly recessed groove 42 at the upper end, the rotating handle 43 is integrally formed in the groove 42 and outwardly protrudes and matches the shape of the groove 42, the structure strength of the rotating handle 43 is improved, the service life is improved, one end of the rotating handle 43 has a larger diameter than the other end and the two ends of the rotating handle 43 have arc-shaped portions 44, the user can easily hold the rotating handle 43 through the groove 42, and the size of the rotating handle 43 can be increased through the arc-shaped portions 44, which is convenient for the user to control.

[0029] The mounting seat 23 is two in number and symmetrically arranged on both sides of the rotating positioning seat 4, and the positioning block 6 in the mounting seat 23 is correspondingly arranged with the positioning groove 41, and the connection stability between the filter core mounting frame 2 and the filter core body 3 is ensured through the two mounting seats 23 and the positioning block 6.

[0030] As shown in Figure 2 , Figure 3 , Figure 4 , Figure 5 , the elastic movable mounting structure 5 includes an arc-shaped recess 51 arranged at one end of the mounting seat 23 close to the rotating positioning seat 4 and matching the outer side of the rotating positioning seat 4, the arc-shaped recess 51 is provided with a mounting channel 52 arranged along the radial direction of the rotating positioning seat 4, one end of the positioning block 6 is arranged in the mounting channel 52 through the guide assembly 7 and the other end is exposed from the mounting channel 52, and the elastic pressing assembly 8 is arranged between the positioning block 6 and the mounting seat 23, the arc-shaped recess 51 can be matched with the side edge of the rotating positioning seat 4, the positioning block 6 can be easily installed and placed through the mounting channel 52, the positioning block 6 can be extended and arranged through the elastic pressing assembly 8, and the positioning block 6 can be limited through the guide assembly 7, so that the positioning block 6 can be displaced towards the rotating positioning seat 4, and the insertion effect is ensured.

[0031] Further, the guide assembly 7 includes a plurality of guide ribs 71 arranged on the inside bottom of the mounting channel 52 and extending along the axial direction of the mounting channel 52, and the guide ribs 71 are in contact with the bottom of the positioning block 6, respectively. The guide ribs 71 can guide the positioning block 6, so that the positioning block 6 can stably and actively displace towards the rotating positioning seat 4.

[0032] The mounting channel 52 penetrates one end of the mounting seat 23 away from the arc-shaped recess 51, and the mounting seat 23 is provided with a slot 231 in communication with the mounting channel 52. The slot 231 is inserted with an insertion plate 232 extending into the mounting channel 52. The insertion plate 232 can be placed through the slot 231, and the opening of the mounting channel 52 at one end can be closed through the insertion plate 232, so that the positioning block 6 can only move towards the other opening.

[0033] As shown in Figure 2 , Figure 3 , Figure 4 , Figure 5 The elastic pressing assembly 8 includes a pressing spring 81 arranged in the mounting channel 52. One end of the pressing spring 81 acts on the spring mounting hole 82 in one end of the positioning block 6, and the other end acts on the insertion plate 232. The positioning block 6 is connected with the pressing spring 81 through the spring mounting hole 82. When the positioning seat 4 rotates, the positioning block 6 extends inward to compress the pressing spring 81. When the positioning block 6 is arranged corresponding to the positioning groove 41, the pressing spring 81 drives the positioning block 6 to move towards the positioning groove 41, ensuring the insertion effect between the positioning block 6 and the positioning groove 41.

[0034] The opening size of one end of the mounting channel 52 close to the arc-shaped recess 51 is smaller than that of the other end, and the positioning block 6 has a limiting portion 61 on both sides of one end in the mounting channel 52, which abuts against the inner side of the opening of one end of the mounting channel 52 close to the arc-shaped recess 51. The limiting portion 61 can limit the displacement distance of the positioning block 6, effectively prevent the positioning block 6 from disengaging from the mounting channel 52, and ensure the installation effect of the positioning block 6.

[0035] Specifically, the positioning groove 41 is arc-shaped, and the depth of the middle part gradually decreases to the depth of both ends. The one end of the positioning block 6 exposed from the mounting channel 52 has a positioning portion 62 matched with the positioning groove 41. The positioning portion 62 can improve the clamping effect between the positioning block 6 and the positioning groove 41, and ensure the stability of the insertion between the filter core body 3 and the filter core mounting frame 2.

[0036] As shown in Figure 3As shown, the upper end of the rotating positioning seat 4 is closed and the lower end is open, the lower end of the rotating positioning seat 4 abuts against the upper end surface of the filter core body 3, a first cylindrical body 45 is coaxially arranged on the circumferential inner side of the lower end of the rotating positioning seat 4, a second cylindrical body 32 is arranged coaxially with the filter core body 3 and located on the circumferential inner side of the first cylindrical body 45 on the upper end of the filter core body 3, the lower end of the first cylindrical body 45 has a first limiting portion 451 which is inwardly bent, the upper end of the second cylindrical body 32 has a second limiting portion 321 which is outwardly bent and axially limited and contacted with the first limiting portion 451, the rotating positioning seat 4 and the filter core body 3 can be positioned and placed through the first cylindrical body 45 and the second cylindrical body 45, the first cylindrical body 45 and the second cylindrical body 32 can be connected through the first limiting portion 451 and the second limiting portion 321, and the connection stability between the filter core body 3 and the filter core mounting frame 2 can be ensured.

[0037] The principle of the embodiment is that the filter core body 3 is arranged in the filter core mounting 21 of the filter core mounting frame 2 and the use efficiency of the filter core body 3 can be ensured through the water inlet interface 22 and the filter core interface 31, the rotating positioning seat 4 is rotated to correspondingly arrange the positioning groove 41 and the positioning block 6, the positioning block 6 can be connected with the rotating positioning seat 4 through the guide assembly 7 and the elastic pressing assembly 8, and the connection between the rotating positioning seat 4 and the filter core body 3 can be ensured through the first limiting portion 451 and the second limiting portion 321, so that the mounting effect of the filter core body 3 and the filter core mounting frame 2 can be ensured.

[0038] The specific embodiments described herein merely exemplify the spirit of the present application. Those skilled in the art to which the present application belongs can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, without departing from the spirit of the present application or exceeding the scope defined by the appended claims.

[0039] Although the terms such as water purifier shell 1, filter core mounting frame 2, filter core mounting cavity 21, water inlet interface 22, mounting seat 23, insertion slot 231, insertion plate 232, filter core body 3, filter core interface 31, second cylindrical body 32, second limiting portion 321, rotating positioning seat 4, positioning groove 41, recess 42, rotating handle 43, arc-shaped portion 44, first cylindrical body 45, first limiting portion 451, elastic movable mounting structure 5, arc-shaped recess 51, mounting passage 52, positioning block 6, limiting portion 61, positioning portion 62, guide assembly 7, guide rib 71, elastic pressing assembly 8, pressing spring 81, spring mounting hole 82 are used more frequently herein, but the possibility of using other terms is not excluded. The use of these terms is only for the convenience of describing and explaining the essence of the present application; any interpretation of them as any kind of additional limitation is contrary to the spirit of the present application.

Claims

1. A water purifier with a rotating unlocking filter core, comprising a water purifier shell (1), wherein a filter core mounting rack (2) is arranged in the water purifier shell (1), at least one filter core mounting cavity (21) is arranged in the filter core mounting rack (2), and a filter core body (3) is arranged in the filter core mounting cavity (21), wherein the lower end of the filter core body (3) is provided with a filter core interface (31) which is inserted into and connected with a water inlet interface (22) located at the lower end of the filter core mounting rack (2) and is connected in a circumferential positioning manner, characterized in that, The filter core body (3) is provided with a rotating positioning seat (4) rotating around the circumference of the filter core body (3) at the upper end of the filter core body (3), the rotating positioning seat (4) is provided with at least one positioning groove (41) recessed radially inward at the outer side of the rotating positioning seat (4), the filter core mounting rack (2) is provided with at least one mounting seat (23) at the outer side of the rotating positioning seat (4) at the upper end of the filter core mounting rack (2), the mounting seat (23) is provided with a positioning block (6) capable of being arranged radially around the rotating positioning seat (4) and clamped in the positioning groove (41) through an elastic movable mounting structure (5) in the mounting seat (23).

2. The water purifier of claim 1, wherein, The number of the positioning grooves (41) is two and the positioning grooves (41) are symmetrically arranged at the two sides of the rotating positioning seat (4), the rotating positioning seat (4) is a cylindrical structure matching the shape of the filter core body (3) and the rotating positioning seat (4) is coaxially connected with the filter core body (3) to rotate, the rotating positioning seat (4) is provided with a recess (42) recessed inward at the upper end of the rotating positioning seat (4), the recess (42) is integrally formed with a rotating handle (43) protruding outward and matching the shape of the recess (42) in the recess (42), one end of the rotating handle (43) is larger in diameter than the other end and the two ends of the rotating handle (43) are respectively provided with arc-shaped portions (44).

3. The water purifier of claim 2, wherein, The number of the mounting seats (23) is two and the mounting seats (23) are symmetrically arranged at the two sides of the rotating positioning seat (4), and the positioning blocks (6) in the mounting seats (23) are one-to-one correspondingly arranged with the positioning grooves (41).

4. The water purifier of claim 1 or 2 or 3, wherein, The elastic movable mounting structure (5) comprises an arc-shaped recessed portion (51) arranged at one end of the mounting seat (23) close to the rotating positioning seat (4) and matching the outer side of the rotating positioning seat (4), the arc-shaped recessed portion (51) is provided with a mounting channel (52) arranged radially around the rotating positioning seat (4) in the arc-shaped recessed portion (51), one end of the positioning block (6) is arranged in the mounting channel (52) through a guide assembly (7) and the other end of the positioning block (6) is exposed from the mounting channel (52), and the positioning block (6) is provided with an elastic pressing assembly (8) between the positioning block (6) and the mounting seat (23).

5. The water purifier of claim 4, wherein, The guide assembly (7) comprises a plurality of guide ribs (71) arranged at the bottom of the inner side of the mounting channel (52) and extending axially along the mounting channel (52), and the guide ribs (71) are respectively in contact with the bottom of the positioning block (6).

6. The water purifier of claim 4, wherein, The mounting channel (52) penetrates through one end of the mounting seat (23) away from the arc-shaped recessed portion (51), and the mounting seat (23) is provided with a slot (231) connected with the mounting channel (52), and the slot (231) is inserted with an insertion plate (232) extending into the mounting channel (52).

7. The water purifier of claim 6, wherein, The elastic pressing assembly (8) comprises a pressing spring (81) arranged in the mounting channel (52), one end of the pressing spring (81) acts on a spring mounting hole (82) in one end of the positioning block (6) and the other end of the pressing spring (81) acts on the insertion plate (232).

8. The water purifier of claim 4, wherein, The opening size of one end of the mounting channel (52) close to the arc-shaped recessed portion (51) is smaller than the opening size of the other end of the mounting channel (52), and the two sides of one end of the positioning block (6) in the mounting channel (52) are respectively provided with limiting portions (61) abutting against the inner side of the opening of one end of the mounting channel (52) close to the arc-shaped recessed portion (51).

9. The water purifier of claim 4, wherein, The positioning groove (41) is arc-shaped, the depth of the middle part of the positioning groove (41) gradually decreases to the depth of the two ends, and the positioning block (6) has a positioning part (62) matching the positioning groove (41) at one end of the exposed installation channel (52).

10. The water purifier of claim 2, wherein, The rotating positioning seat (4) is closed at the upper end and open at the lower end, the lower end of the rotating positioning seat (4) abuts against the upper end surface of the filter core body (3), a first cylindrical body (45) is coaxially arranged on the circumferential inner side of the lower end of the rotating positioning seat (4), a second cylindrical body (32) is coaxially arranged on the upper end of the filter core body (3) and located on the circumferential inner side of the first cylindrical body (45), the lower end of the first cylindrical body (45) has a first limiting part (451) which is bent inward in the circumferential direction, and the upper end of the second cylindrical body (32) has a second limiting part (321) which is bent outward in the circumferential direction and axially limited and contacted with the first limiting part (451).

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