Miniature loudspeaker

Abstract

The utility model discloses a miniature loudspeaker, which comprises a yoke, an annular frame, a central magnetic structure, an inner side magnetic structure, an outer side magnetic structure, a high pitch unit and a low pitch unit, the central magnetic structure is positioned in the inner side magnetic structure, and a high pitch magnetic gap is formed between the inner side magnetic structure and the central magnetic structure; the whole outer edge magnetic structure is in a ring frame shape, and a bass magnetic gap is formed between the inner edge magnetic structure and the outer edge magnetic structure; the high-pitch unit comprises a high-pitch vibrating diaphragm, a high-pitch middle patch and a high-pitch voice coil, the high-pitch vibrating diaphragm and the high-pitch middle patch are respectively in an annular frame shape, the inner edge of the high-pitch vibrating diaphragm is connected with the high-pitch middle patch and the high-pitch voice coil, and the outer edge of the high-pitch vibrating diaphragm is connected with the outer magnetic structure; the bass unit comprises a bass middle patch, a bass voice coil and a bass vibrating diaphragm which is respectively connected with the bass middle patch, the bass voice coil and the high-pitch middle patch. The miniature loudspeaker is novel in structure, is provided with the high pitch unit and the low pitch unit, and facilitates the optimization of the occupation of the whole machine space. And an independent bilateral magnetic structure is adopted, so that the manufacturing difficulty of the magnetic steel is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of electroacoustic converters, in particular to a miniature loudspeaker. Background Art

[0002] Nowadays, mobile terminals such as mobile phones and tablets enrich people's lives, and micro speakers play an indispensable role as audio devices.

[0003] As consumers have higher and higher requirements for the sound quality and loudness of the whole machine, the requirements for micro speakers are also further improved. In order to achieve a better experience, multiple micro speakers are often placed in a speaker, including a woofer, a midrange unit and a tweeter. The filter can filter out the redundant frequency bands and retain the desired effective bandwidth. Although the sound quality has improved, the size of the speaker has also increased and become bulky, and the cost has also increased. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a miniature loudspeaker having both a tweeter unit and a bass unit.

[0005] In order to solve the above technical problems, the technical solution adopted by the utility model is: a miniature speaker, comprising:

[0006] A yoke, wherein the yoke has a flange;

[0007] An annular basin frame, wherein the flange is located inside the annular basin frame and connected to the annular basin frame;

[0008] A central magnetic structure, wherein the central magnetic structure is disposed on the yoke;

[0009] An inner magnetic structure, wherein the inner magnetic structure is in the shape of a ring frame as a whole, the inner magnetic structure is located above the annular basin frame and connected to the annular basin frame, the central magnetic structure is located inside the inner magnetic structure, and a treble magnetic gap is formed between the inner magnetic structure and the central magnetic structure;

[0010] An outer magnetic structure, the outer magnetic structure is in the shape of a ring frame as a whole, the inner magnetic structure is located inside the outer magnetic structure and forms a bass magnetic gap with the outer magnetic structure, and the outer magnetic structure is connected to the annular basin frame;

[0011] A tweeter unit, the tweeter unit comprising a tweeter diaphragm, a tweeter middle sticker and a tweeter voice coil, the tweeter diaphragm and the tweeter middle sticker are respectively in the shape of a ring frame, the inner edge of the tweeter diaphragm is connected to the tweeter middle sticker and the tweeter voice coil, the outer edge of the tweeter diaphragm is connected to the outer magnetic structure, and the tweeter voice coil moves in the tweeter magnetic gap;

[0012] A woofer unit comprises a woofer middle sticker, a woofer voice coil and a woofer diaphragm respectively connected to the woofer middle sticker, the woofer voice coil and the treble middle sticker, and the woofer voice coil moves in the woofer magnetic gap.

[0013] Furthermore, it also includes a supporting auxiliary membrane, and the supporting auxiliary membranes are respectively arranged on the opposite sides of the bass voice coil, the inner edge of the supporting auxiliary membrane is connected to the bass voice coil, the outer edge of the supporting auxiliary membrane is connected to the flange and / or the outer magnetic structure, and the supporting auxiliary membrane is arranged corresponding to the edge of the inner magnetic structure that is not connected to the annular basin frame.

[0014] Further, the short axis of the inner magnetic structure is connected to the annular frame, and the supporting sub-membrane is arranged corresponding to the long axis of the inner magnetic structure; or, the long axis of the inner magnetic structure is connected to the annular frame, and the supporting sub-membrane is arranged corresponding to the short axis of the inner magnetic structure.

[0015] Furthermore, the central magnetic structure includes a central magnetic steel and a central washer, the central magnetic steel connects the central washer and the yoke, and the central magnetic structure is located between at least one group of relatively arranged flanges.

[0016] Furthermore, the yoke is rectangular as a whole, and the four sides of the yoke are correspondingly provided with the flanges.

[0017] Furthermore, a partial area of ​​the bottom surface of the inner edge magnetic structure contacts the top surface of the flange.

[0018] Furthermore, a partial area of ​​the bottom surface of the inner edge magnetic structure is connected to the top surface of the flange.

[0019] Furthermore, the inner magnetic structure includes an inner magnetic steel and an inner washer, the inner magnetic steel and the inner washer are respectively in the shape of a ring frame, the bottom surface of the inner magnetic steel is connected to the annular basin frame, and the top surface of the inner magnetic steel is connected to the inner washer.

[0020] Furthermore, the external magnetic structure includes an external magnetic steel and an external washer, the external magnetic steel and the external washer are respectively in the shape of an annular frame, the bottom surface of the external magnetic steel is connected to the annular basin frame, the top surface of the external magnetic steel is connected to the external washer, the outer edge of the external washer has a protruding surrounding wall, and the outer edge of the tweeter diaphragm is connected to the surrounding wall.

[0021] Furthermore, a first positioning structure is provided on the outer magnetic structure, and a second positioning structure cooperating with the first positioning structure is provided on the annular basin frame.

[0022] The beneficial effects of the utility model are as follows: the micro speaker has a novel structure, has a tweeter and a woofer, is conducive to optimizing the space occupied by the whole machine, conforms to the development trend of thin and light electronic equipment, and meets the high requirements of users for the sound quality of electroacoustic converters. The independent bilateral magnetic structure is adopted, which reduces the difficulty of manufacturing magnetic steel and is conducive to controlling the production cost of the micro speaker. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the structure of a micro speaker according to Embodiment 1 of the present utility model;

[0024] Figure 2 is a cross-sectional view of the micro-speaker of the first embodiment of the utility model;

[0025] Figure 3 is a cross-sectional view of the micro-speaker of the first embodiment of the utility model at another viewing angle;

[0026] Figure 4 This is an exploded view of the micro speaker according to the first embodiment of the present invention.

[0027] Description of labels:

[0028] 1. Yoke iron; 11. Flanging;

[0029] 2. Annular basin stand; 21. Positioning column;

[0030] 3. Center magnetic structure; 31. Center magnetic steel; 32. Center washer;

[0031] 4. Inner magnetic structure; 41. Inner magnetic steel; 42. Inner washer;

[0032] 5. External magnetic structure; 51. External magnetic steel; 511. Positioning hole; 52. External washer; 521. Surrounding wall;

[0033] 6. Tweeter unit; 61. Tweeter diaphragm; 62. Tweeter mid-strip; 63. Tweeter voice coil;

[0034] 7. Bass unit; 71. Bass diaphragm; 72. Bass center sticker; 73. Bass voice coil;

[0035] 8. Support the secondary film. DETAILED DESCRIPTION

[0036] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes and the accompanying drawings.

[0037] Please refer to Figures 1 to 4 , a micro speaker, comprising:

[0038] A yoke 1, wherein the yoke 1 has a flange 11;

[0039] An annular basin frame 2, wherein the flange 11 is located inside the annular basin frame 2 and connected to the annular basin frame 2;

[0040] A central magnetic structure 3, wherein the central magnetic structure 3 is arranged on the yoke 1;

[0041] The inner magnetic structure 4 is in the shape of a ring frame as a whole. The inner magnetic structure 4 is located above the annular basin frame 2 and connected to the annular basin frame 2. The central magnetic structure 3 is located in the inner magnetic structure 4. A treble magnetic gap is formed between the inner magnetic structure 4 and the central magnetic structure 3.

[0042] The outer magnetic structure 5 is in the shape of a ring frame as a whole, the inner magnetic structure 4 is located inside the outer magnetic structure 5 and forms a bass magnetic gap with the outer magnetic structure 5, and the outer magnetic structure 5 is connected to the annular basin frame 2;

[0043] A tweeter unit 6, the tweeter unit 6 comprises a tweeter diaphragm 61, a tweeter middle sticker 62 and a tweeter voice coil 63, the tweeter diaphragm 61 and the tweeter middle sticker 62 are respectively in the shape of a ring frame, the inner edge of the tweeter diaphragm 61 is connected to the tweeter middle sticker 62 and the tweeter voice coil 63, the outer edge of the tweeter diaphragm 61 is connected to the outer magnetic structure 5, and the tweeter voice coil 63 moves in the tweeter magnetic gap;

[0044] The bass unit 7 includes a bass middle sticker 72, a bass voice coil 73 and a bass diaphragm 71 respectively connected to the bass middle sticker 72, the bass voice coil 73 and the treble middle sticker 62, and the bass voice coil 73 moves in the bass magnetic gap.

[0045] From the above description, it can be seen that the beneficial effects of the utility model are: the micro speaker has a novel structure, and has both a tweeter unit 6 and a woofer unit 7, which is conducive to optimizing the space occupied by the whole machine, conforming to the development trend of thin and light electronic equipment, and meeting the high requirements of users for the sound quality of the electroacoustic converter. The use of an independent bilateral magnetic structure reduces the difficulty of manufacturing the magnetic steel, which is conducive to controlling the production cost of the micro speaker.

[0046] Furthermore, it also includes a supporting auxiliary membrane 8, and the supporting auxiliary membranes 8 are respectively provided on the opposite sides of the bass voice coil 73, the inner edge of the supporting auxiliary membrane 8 is connected to the bass voice coil 73, the outer edge of the supporting auxiliary membrane 8 is connected to the flange 11 and / or the outer magnetic structure 5, and the supporting auxiliary membrane 8 is arranged corresponding to the edge of the inner magnetic structure 4 that is not connected to the annular basin frame 2.

[0047] From the above description, it can be seen that the setting of the supporting auxiliary membrane 8 can improve the rolling vibration and polarization phenomenon of the bass voice coil 73, which is beneficial to improving the acoustic performance of the micro speaker. The use of the supporting auxiliary membrane 8 to support the bass voice coil 73 can optimize the KMS linearity, while increasing the amplitude vibration space and increasing the low-frequency sound pressure radiation energy. The supporting auxiliary membrane 8 bypasses the inner magnetic structure 4 and is connected and fixed to the flange 11 and / or the outer magnetic structure 5, so that the volume of the inner magnetic structure 4 can be set larger, thereby improving the BL value and linearity of the micro speaker, thereby improving the loudness of the micro speaker.

[0048] Further, the short axis of the inner edge magnetic structure 4 is connected to the annular basin frame 2, and the supporting sub-membrane 8 is arranged corresponding to the long axis of the inner edge magnetic structure 4; or, the long axis of the inner edge magnetic structure 4 is connected to the annular basin frame 2, and the supporting sub-membrane 8 is arranged corresponding to the short axis of the inner edge magnetic structure 4.

[0049] It can be seen from the above description that the specific connection position between the supporting auxiliary membrane 8 and the bass voice coil 73 can be set as needed.

[0050] Furthermore, the central magnetic structure 3 includes a central magnetic steel 31 and a central washer 32 , the central magnetic steel 31 connects the central washer 32 and the yoke 1 , and the central magnetic structure 3 is located between at least one set of the relatively arranged flanges 11 .

[0051] Furthermore, the yoke 1 is rectangular as a whole, and the flanges 11 are correspondingly provided on the four sides of the yoke 1 .

[0052] Furthermore, a partial area of ​​the bottom surface of the inner magnetic structure 4 contacts the top surface of the flange 11 .

[0053] It can be seen from the above description that the flange 11 can provide certain support for the inner magnetic structure 4 .

[0054] Furthermore, a partial area of ​​the bottom surface of the inner magnetic structure 4 is connected to the top surface of the flange 11 .

[0055] It can be seen from the above description that the connection of the top surface of the flange 11 to a partial area of ​​the bottom surface of the inner magnetic structure 4 can improve the structural stability of the micro speaker.

[0056] Furthermore, the inner magnetic structure 4 includes an inner magnetic steel 41 and an inner washer 42 , the inner magnetic steel 41 and the inner washer 42 are respectively in the shape of a ring frame, the bottom surface of the inner magnetic steel 41 is connected to the annular basin frame 2 , and the top surface of the inner magnetic steel 41 is connected to the inner washer 42 .

[0057] Furthermore, the external magnetic structure 5 includes an external magnetic steel 51 and an external washer 52, the external magnetic steel 51 and the external washer 52 are respectively in the shape of an annular frame, the bottom surface of the external magnetic steel 51 is connected to the annular basin frame 2, the top surface of the external magnetic steel 51 is connected to the external washer 52, the outer edge of the external washer 52 has a protruding surrounding wall 521, and the outer edge of the tweeter diaphragm 61 is connected to the surrounding wall 521.

[0058] Furthermore, a first positioning structure is provided on the outer magnetic structure 5 , and a second positioning structure cooperating with the first positioning structure is provided on the annular basin frame 2 .

[0059] It can be seen from the above description that the cooperation between the first positioning structure and the second positioning structure can facilitate the assembly and production of the micro speaker.

[0060] Embodiment 1

[0061] Please refer to Figures 1 to 4 , Embodiment 1 of the present utility model is: a miniature speaker that can be applied to electronic products such as mobile phones, tablet computers, smart watches, etc.

[0062] The micro-speaker comprises a yoke 1, an annular basin frame 2, a central magnetic structure 3, an inner magnetic structure 4, an outer magnetic structure 5, a tweeter 6 and a woofer 7, wherein the yoke 1 has a flange 11, which is formed by bending a part of the edge of the yoke 1, and the flange 11 is located in the annular basin frame 2 and connected to the annular basin frame 2, and the central magnetic structure 3 is arranged on the yoke 1; the inner magnetic structure 4 is in the shape of a ring frame as a whole, and the inner magnetic structure 4 is located above the annular basin frame 2 and connected to the annular basin frame 2, and the bottom surface of the central magnetic structure 3 is arranged lower than the bottom surface of the inner magnetic structure 4, and the central magnetic structure 3 is located in the inner magnetic structure 4, and a tweeter magnetic gap is formed between the inner magnetic structure 4 and the central magnetic structure 3; the outer magnetic structure 5 is in the shape of a ring frame as a whole The inner magnetic structure 4 is located inside the outer magnetic structure 5 and forms a bass magnetic gap with the outer magnetic structure 5. The bottom surface of the outer magnetic structure 5 is connected to the annular basin frame 2. The tweeter unit 6 includes a tweeter diaphragm 61, a tweeter middle sticker 62 and a tweeter voice coil 63. The tweeter diaphragm 61 and the tweeter middle sticker 62 are respectively in the shape of a ring frame. The inner edge of the tweeter diaphragm 61 is connected to the tweeter middle sticker 62 and the tweeter voice coil 63. The outer edge of the tweeter diaphragm 61 is connected to the outer magnetic structure 5. The tweeter voice coil 63 moves in the tweeter magnetic gap. The bass unit 7 includes a bass middle sticker 72, a bass voice coil 73 and a bass diaphragm 71 respectively connected to the bass middle sticker 72, the bass voice coil 73 and the tweeter middle sticker 62. The bass voice coil 73 moves in the bass magnetic gap.

[0063] It is easy to understand that the tweeter diaphragm 61 adopts a tweeter rigid diaphragm with high strength and low compliance; the material of the tweeter middle paste 62 can be high-density strength materials such as stainless steel and magnesium-aluminum alloy; the bass middle paste 72 uses a heavier bass dome, and its material can be bakelite, aluminum + PMI sandwich composite structure, etc.

[0064] The micro-speaker also includes a supporting sub-diaphragm 8, and the supporting sub-diaphragms 8 are respectively arranged on the opposite sides of the bass voice coil 73, the inner edge of the supporting sub-diaphragm 8 is connected to the bass voice coil 73, and the outer edge of the supporting sub-diaphragm 8 is connected to the flange 11 and / or the outer magnetic structure 5. The supporting sub-diaphragm 8 is arranged corresponding to the edge of the inner magnetic structure 4 that is not connected to the annular basket frame 2. It is easy to understand that there will be a certain height difference between the bottom surface of the edge of the inner magnetic structure 4 that is not connected to the annular basket frame 2 and the yoke 1, so that the supporting sub-diaphragm 8 can pass through and provide a movable space for the supporting sub-diaphragm 8. In other words, the bottom surface of the edge of the inner magnetic structure 4 that is not connected to the annular basket frame 2 is in a suspended state.

[0065] In this embodiment, the short axis of the inner edge magnetic structure 4 is connected to the annular basin frame 2, and the supporting sub-membrane 8 is arranged corresponding to the long axis of the inner edge magnetic structure 4; in other embodiments, the long axis of the inner edge magnetic structure 4 is connected to the annular basin frame 2, and the supporting sub-membrane 8 is arranged corresponding to the short axis of the inner edge magnetic structure 4.

[0066] The central magnetic structure 3 includes a central magnetic steel 31 and a central washer 32. The central magnetic steel 31 connects the central washer 32 and the yoke 1. The central magnetic structure 3 is located between at least one set of oppositely arranged flanges 11. In order to improve the structural strength of the yoke 1 and the structural stability of the micro speaker as a whole, in this embodiment, the yoke 1 is rectangular as a whole, and the flanges 11 are correspondingly provided on the four sides of the yoke 1.

[0067] Optionally, a portion of the bottom surface of the inner magnetic structure 4 contacts the top surface of the flange 11. Preferably, a portion of the bottom surface of the inner magnetic structure 4 is connected to the top surface of the flange 11, which may be connected by gluing or other methods.

[0068] The inner magnetic structure 4 includes an inner magnetic steel 41 and an inner washer 42. The inner magnetic steel 41 and the inner washer 42 are respectively in the shape of a ring frame. The bottom surface of the inner magnetic steel 41 is connected to the annular basin frame 2, and the top surface of the inner magnetic steel 41 is connected to the inner washer 42. It should be noted that, although in the present embodiment, the inner magnetic steel 41 and the inner washer 42 are respectively continuous and complete ring frame structures, in actual products, one of the inner magnetic steel 41 and the inner washer 42 may be a non-continuous and complete ring frame structure.

[0069] The external magnetic structure 5 includes an external magnetic steel 51 and an external washer 52. The external magnetic steel 51 and the external washer 52 are respectively in the shape of ring frames. The bottom surface of the external magnetic steel 51 is connected to the annular basin frame 2, and the top surface of the external magnetic steel 51 is connected to the external washer 52. The outer edge of the external washer 52 has a protruding surrounding wall 521, and the outer edge of the tweeter diaphragm 61 is connected to the surrounding wall 521. The existence of the surrounding wall 521 can provide an avoidance space for the movement of the tweeter diaphragm 61.

[0070] The outer magnetic structure 5 is provided with a first positioning structure, and the annular frame 2 is provided with a second positioning structure that cooperates with the first positioning structure. In this embodiment, the first positioning structure is a positioning hole 511 provided on the outer magnetic steel 51, and the second positioning structure is a positioning column 21 provided on the annular frame 2.

[0071] In summary, the micro-speaker provided by the utility model has a novel structure and has both a tweeter and a woofer, which is conducive to optimizing the space occupied by the whole machine, conforms to the development trend of lightweight electronic equipment, and meets the high requirements of users for the sound quality of electroacoustic converters. The use of an independent bilateral magnetic structure reduces the difficulty of manufacturing magnetic steel, which is conducive to controlling the production cost of micro-speakers. The setting of the supporting sub-diaphragm can improve the rolling vibration and polarization phenomenon of the bass voice coil, which is conducive to improving the acoustic performance of the micro-speaker. The use of a supporting sub-diaphragm to support the bass voice coil can optimize the KMS linearity, and at the same time can increase the amplitude vibration space and increase the low-frequency sound pressure radiation energy. The supporting sub-diaphragm bypasses the inner magnetic structure and is connected and fixed to the flange and / or the outer magnetic structure, so that the volume of the inner magnetic structure can be set larger, thereby improving the BL value and linearity of the micro-speaker, thereby improving the loudness of the micro-speaker.

[0072] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent transformations made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in the relevant technical field, are also included in the patent protection scope of the present invention.

Claims

1. A micro speaker, characterized in that: include A yoke, wherein the yoke has a flange; An annular basin frame, wherein the flange is located inside the annular basin frame and connected to the annular basin frame; A central magnetic structure, wherein the central magnetic structure is disposed on the yoke; An inner magnetic structure, wherein the inner magnetic structure is in the shape of a ring frame as a whole, the inner magnetic structure is located above the annular basin frame and connected to the annular basin frame, the central magnetic structure is located inside the inner magnetic structure, and a treble magnetic gap is formed between the inner magnetic structure and the central magnetic structure; An outer magnetic structure, the outer magnetic structure is in the shape of a ring frame as a whole, the inner magnetic structure is located inside the outer magnetic structure and forms a bass magnetic gap with the outer magnetic structure, and the outer magnetic structure is connected to the annular basin frame; A tweeter unit, the tweeter unit comprising a tweeter diaphragm, a tweeter middle sticker and a tweeter voice coil, the tweeter diaphragm and the tweeter middle sticker are respectively in the shape of a ring frame, the inner edge of the tweeter diaphragm is connected to the tweeter middle sticker and the tweeter voice coil, the outer edge of the tweeter diaphragm is connected to the outer magnetic structure, and the tweeter voice coil moves in the tweeter magnetic gap; A woofer unit comprises a woofer middle sticker, a woofer voice coil and a woofer diaphragm respectively connected to the woofer middle sticker, the woofer voice coil and the treble middle sticker, and the woofer voice coil moves in the woofer magnetic gap.

2. The micro-speaker according to claim 1, characterized in that: It also includes a supporting auxiliary membrane, which is respectively provided on two opposite sides of the bass coil, the inner edge of the supporting auxiliary membrane is connected to the bass coil, the outer edge of the supporting auxiliary membrane is connected to the flange and / or the outer magnetic structure, and the supporting auxiliary membrane is arranged corresponding to the edge of the inner magnetic structure that is not connected to the annular basin frame.

3. The micro-speaker according to claim 2, characterized in that: The short axis of the inner magnetic structure is connected to the annular frame, and the supporting auxiliary membrane is arranged corresponding to the long axis of the inner magnetic structure; or, the long axis of the inner magnetic structure is connected to the annular frame, and the supporting auxiliary membrane is arranged corresponding to the short axis of the inner magnetic structure.

4. The micro-speaker according to claim 1, characterized in that: The central magnetic structure includes a central magnetic steel and a central washer, the central magnetic steel connects the central washer and the yoke, and the central magnetic structure is located between at least one group of relatively arranged flanges.

5. The micro-speaker according to claim 1, characterized in that: The yoke is rectangular as a whole, and the four sides of the yoke are correspondingly provided with the flanges.

6. The micro-speaker according to claim 1, characterized in that: A partial area of ​​the bottom surface of the inner magnetic structure contacts the top surface of the flange.

7. The micro-speaker according to claim 6, characterized in that: A partial area of ​​the bottom surface of the inner edge magnetic structure is connected to the top surface of the flange.

8. The micro-speaker according to claim 1, characterized in that: The inner magnetic structure includes an inner magnetic steel and an inner washer. The inner magnetic steel and the inner washer are respectively in the shape of an annular frame. The bottom surface of the inner magnetic steel is connected to the annular basin frame, and the top surface of the inner magnetic steel is connected to the inner washer.

9. The micro-speaker according to claim 1, characterized in that: The external magnetic structure includes an external magnetic steel and an external washer. The external magnetic steel and the external washer are respectively in the shape of an annular frame. The bottom surface of the external magnetic steel is connected to the annular basin frame. The top surface of the external magnetic steel is connected to the external washer. The outer edge of the external washer has a protruding surrounding wall. The outer edge of the tweeter diaphragm is connected to the surrounding wall.

10. The micro-speaker according to claim 1, characterized in that: The outer magnetic structure is provided with a first positioning structure, and the annular basin frame is provided with a second positioning structure matched with the first positioning structure.

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