Sound production device and electronic equipment

Abstract

The invention discloses a sound production device and electronic equipment, and relates to the technical field of electroacoustic transduction, a magnetic conductive yoke of a magnetic circuit system of the sound production device comprises a first top plate and a first bottom plate, a central magnetic part and an edge magnetic part are respectively arranged on the first top plate and the first bottom plate, and are respectively separated from an annular magnet to form a first magnetic gap and a second magnetic gap; the supporting piece and the first top plate define an airflow cavity, the first top plate is provided with a first through hole, the supporting piece is provided with a second through hole, the magnetic circuit system is further provided with a through hole sequentially penetrating through the center magnetic part and the first top plate, a first vibrating diaphragm and a second vibrating diaphragm of the vibrating system are located on the two opposite sides of the magnetic circuit system, and the inner periphery of the second vibrating diaphragm is connected with the supporting piece. And the inner periphery of the second vibrating diaphragm is provided with a third through hole communicated with the second through hole. According to the sound production device, the high-frequency performance is improved, and the vibration area of the vibration system is increased, so that the performance and the effect of the whole machine are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electroacoustic transducers, and particularly to a sound generating device and an electronic device applying the sound generating device. Background Art

[0002] In recent years, with the rapid development of consumer electronic products, electronic devices such as headphones, smart phones, and VR devices have been recognized by consumers and widely used. Those skilled in the art have also correspondingly improved related supporting products such as headphones to meet the performance requirements of electronic products and the needs of consumers for product performance.

[0003] The sound generating device is an important electroacoustic transducer component in consumer electronic products, and is widely used as a loudspeaker, a receiver, a headphone, etc. With the improvement of the performance of electronic products, the improvement of the acoustic performance of the sound generating device is also an inevitable trend. In related technologies, in order to improve the performance of the sound generating device, the product design is becoming more and more extreme, and the space utilization rate is also getting higher and higher, resulting in risks in the reliability of the product, and at the same time being unfavorable for the improvement of high-frequency performance, resulting in poor overall performance and effect of the whole machine. Summary of the Invention

[0004] The main object of the present invention is to provide a sound generating device and an electronic device, aiming to provide a sound generating device that effectively improves high-frequency performance. The sound generating device not only reduces the reliability risk, but also effectively improves high-frequency performance, thereby improving the performance and effect of the whole machine.

[0005] To achieve the above object, the present invention provides a sound generating device, the sound generating device comprising:

[0006] A housing;

[0007] A magnetic circuit system, the magnetic circuit system being connected to the housing, the magnetic circuit system comprising a central magnetic part, a side magnetic part, a ring magnet, a magnetic yoke and a support member, the magnetic yoke comprising a first top plate and a first bottom plate provided at both ends of the ring magnet, the central magnetic part being provided on the first top plate and spaced from the ring magnet to form a first magnetic gap, the side magnetic part being provided on the first bottom plate and spaced from the ring magnet to form a second magnetic gap, the second magnetic gap surrounding the first magnetic gap, the support member being provided on a side of the first top plate facing away from the central magnetic part and enclosing with the first top plate to form an air flow cavity, the first top plate being provided with a first through hole communicating the first magnetic gap and the air flow cavity, the support member being provided with a second through hole communicating the air flow cavity, the magnetic circuit system further being provided with a through hole sequentially penetrating the central magnetic part and the first top plate, the through hole communicating with the air flow cavity; and

[0008] A vibration system, the vibration system includes a first diaphragm, a second diaphragm, a first voice coil and a second voice coil. The first diaphragm and the second diaphragm are located on opposite sides of the magnetic circuit system. The outer peripheral edge of the first diaphragm is connected to the housing and is opposite to and spaced from the magnetic circuit system. The outer peripheral edge of the second diaphragm is connected to the housing, and the inner peripheral edge of the second diaphragm is connected to the support member. A third through hole communicating with the second through hole is provided at the inner peripheral edge of the second diaphragm. One end of the first voice coil is connected to the first diaphragm, and the other end of the first voice coil is suspended in the first magnetic gap. One end of the second voice coil is connected to the second diaphragm, and the other end of the second voice coil is suspended in the second magnetic gap;

[0009] Wherein, the sound generating device has a first side of the second diaphragm facing away from the first diaphragm and a second side of the first diaphragm facing away from the second diaphragm. The sound wave of the first diaphragm facing the first side is radiated outward through the through hole, the air flow cavity, the second through hole and the third through hole, and at the same time is radiated outward through the first magnetic gap, the first through hole, the air flow cavity, the second through hole and the third through hole, and jointly radiates to the first side with the sound wave of the second diaphragm facing the first side.

[0010] In an embodiment, the first top plate and the first bottom plate are connected to two ends of the annular magnet along the vibration direction of the vibration system. The first top plate includes a convex portion and a support portion connected to each other. The convex portion protrudes from the first top plate toward the central magnetic portion so that the support portion surrounds the convex portion;

[0011] Wherein, the support portion is provided with the first through hole, the central magnetic portion is arranged on the convex portion and is spaced from the support portion to enclose an air flow channel. The air flow channel communicates the first magnetic gap and the first through hole. The support member is connected to a side of the support portion facing away from the air flow channel. The through hole sequentially penetrates through the central magnetic portion and the convex portion.

[0012] In an embodiment, an inclined surface is formed at the connection between the convex portion and the support portion, and the first through hole sequentially penetrates through the support portion and the inclined surface;

[0013] And / or, there are a plurality of the first through holes, and the plurality of first through holes are arranged at intervals and surround the convex portion;

[0014] And / or, the first through hole is an arc-shaped hole extending along the peripheral edge of the convex portion;

[0015] And / or, a support groove is formed by the side of the support portion facing the support member being recessed toward the air flow channel, and the periphery of the support member is limited in the support groove;

[0016] And / or, the first bottom plate is provided with an avoidance groove corresponding to the second magnetic gap, and the avoidance groove is used to provide avoidance for the second voice coil;

[0017] And / or, define the area of the first top plate as S1, define the opening area of the through hole as S2, and S2 = (10% - 80%)S1;

[0018] And / or, the central magnetic part includes a central magnet and a central magnetic conductive plate stacked, the central magnet is connected to the convex part, and the through hole sequentially penetrates the central magnetic conductive plate, the central magnet and the convex part.

[0019] In one embodiment, the support member includes a second top plate, a second side plate provided at the periphery of the second top plate, and a second bottom plate formed by extending outward from one end of the second side plate away from the second top plate. The second bottom plate is connected to the side of the first top plate facing away from the central magnetic part, so that the second top plate, the second side plate and the first top plate enclose to form the air flow cavity. The second top plate is provided with the second through hole, and the inner periphery of the second diaphragm is connected to the side of the second top plate facing away from the air flow cavity, so that the third through hole is communicated with the second through hole;

[0020] Wherein, there is one second through hole, and the second through hole is correspondingly communicated with the third through hole; or, the second through hole includes a plurality of second through holes, and the plurality of second through holes are arranged at intervals; and / or, define the area of the second top plate as S3, define the opening area of the second through hole as S4, and S4 = (10% - 80%)S3; and / or, the support member is a metal part, and the second bottom plate is adhesively connected or welded to the first top plate; or, the support member is an injection molded part, and the support member and the first top plate are integrally injection molded.

[0021] In one embodiment, a first cavity is formed between the second diaphragm, the housing, the annular magnet, the magnetic yoke and the support member, and the housing is provided with a first leakage hole communicating the first cavity with the outside;

[0022] Wherein, the sound wave of the second diaphragm facing the second side is radiated outward through the first leakage hole, and jointly radiates to the second side with the sound wave of the first diaphragm facing the second side.

[0023] In one embodiment, the housing includes a first housing and a second housing connected to each other. One end of the first housing away from the second housing is connected to the outer periphery of the first diaphragm, one side of the second housing facing away from the first housing is connected to the outer periphery of the second diaphragm, and the outer periphery of the first bottom plate is connected to the first housing;

[0024] Wherein, the first housing is provided with the first leakage hole, the first leakage hole penetrates through the surface of the first housing facing the second side, and the first leakage hole is located outside the first diaphragm; alternatively, the first leakage hole is provided on the side wall of the first housing or the second housing; alternatively, the first leakage hole is formed at the connection between the first housing and the second housing.

[0025] In an embodiment, a support platform is convexly provided on the inner wall of the first housing, the outer peripheral edge of the first bottom plate and the outer peripheral edge of the first diaphragm are respectively arranged on both sides of the support platform, and the first leakage hole is formed between the inner wall of the first housing and the support platform;

[0026] And / or, the edge magnetic part includes a laminated edge magnet and an edge magnetic conductive plate, the edge magnet is connected to the first bottom plate, the edge magnetic conductive plate is connected to the second housing, and a leakage channel communicating with the first leakage hole is formed between the edge magnetic conductive plate and the second housing.

[0027] In an embodiment, the first diaphragm includes a surround part and a dome, the surround part surrounds the dome, the outer edge of the surround part is connected to the outer shell, and the first voice coil is connected to the dome;

[0028] And / or, the second diaphragm includes an inner surround, a vibrating part and an outer surround which are connected in sequence, the inner peripheral edge of the inner surround is connected to the support member and is provided with the third through hole, the outer side of the outer surround is connected to the outer shell, and the second voice coil is connected to the vibrating part; wherein, the second diaphragm further includes a vibrating plate, and the vibrating plate is arranged between the vibrating part and the second voice coil.

[0029] In an embodiment, the sound generating device further includes a front cover, the periphery of the front cover is connected to the outer shell and is located on the side of the first diaphragm facing away from the second diaphragm, a second cavity is formed between the first diaphragm and the front cover, and the front cover is provided with a fourth through hole communicating the second cavity and the outside;

[0030] Wherein, the sound wave of the first diaphragm facing the second side is radiated outward through the fourth through hole.

[0031] In an embodiment, a support boss and a retaining wall connected to the support boss are further provided at one end of the outer shell facing away from the second diaphragm, the front cover includes a top cover part, a side plate part provided on the periphery of the top cover part, and an edge part extending outward from one end of the side plate part away from the top cover part, the edge part is supported on the support boss, the surface of the retaining wall facing the second side protrudes from the surface of the edge part facing the second side, and the top cover part is provided with the fourth through hole;

[0032] Alternatively, the front cover includes a top cover portion, a side plate portion provided at the periphery of the top cover portion, an edge portion extending outward from one end of the side plate portion away from the top cover portion, and a bent portion formed by bending and extending the edge portion. The bent portion is connected to the housing, and the bent portion and the edge portion form a limiting space with the housing. The periphery of the first diaphragm is limited within the limiting space, and the fourth through hole is provided in the top cover portion.

[0033] In one embodiment, the first diaphragm and the second diaphragm vibrate in the same direction. The first diaphragm and the second diaphragm radiate a first sound wave to the external environment on the first side, and the first diaphragm and the second diaphragm radiate a second sound wave to the external environment on the second side. The first sound wave and the second sound wave are out of phase; or, the sound generating device is applied to an electronic device and is used to divide the space of the electronic device into an acoustically isolated front cavity and a rear cavity. The first side communicates with the front cavity, and the second side communicates with the rear cavity. The first diaphragm and the second diaphragm vibrate in the same direction, radiate a first sound wave to the front cavity, and radiate a second sound wave to the rear cavity. The first sound wave and the second sound wave are out of phase;

[0034] And / or, the second diaphragm is annular, the inner edge of the second diaphragm forms the third through hole, and the sound generating device further includes a second air-permeable member connected to the inner edge of the second diaphragm and covering the third through hole;

[0035] And / or, the sound generating device further includes a first positioning ring provided between the outer periphery of the first diaphragm and the housing;

[0036] And / or, the sound generating device further includes a second positioning ring provided between the outer periphery of the second diaphragm and the housing.

[0037] The present invention also provides an electronic device, which includes:

[0038] A device housing provided with a receiving cavity; and

[0039] The above-mentioned sound generating device is provided in the receiving cavity and divides the receiving cavity into a mutually isolated front cavity and a rear cavity. The first side of the sound generating device communicates with the front cavity;

[0040] Wherein, the device housing is provided with a sound outlet hole communicating with the front cavity, and the sound waves of the first diaphragm and the second diaphragm of the sound generating device facing the first side are radiated to the outside through the front cavity and the sound outlet hole.

[0041] In one embodiment, the device housing is further provided with a second leakage hole communicating with the rear cavity;

[0042] Among them, the first diaphragm and the second diaphragm of the sound generating device radiate sound waves with a phase opposite to that of the sound waves in the front cavity towards the rear cavity, and the sound waves in the rear cavity are radiated to the outside through the second leakage hole.

[0043] The sound generating device of the technical solution of the present invention houses a magnetic circuit system and a vibration system in a housing, and a first magnetic gap and a second magnetic gap are provided on the magnetic circuit system, such that the second magnetic gap surrounds the first magnetic gap. The vibration system is set as a first diaphragm, a second diaphragm, a first voice coil and a second voice coil. The first diaphragm and the second diaphragm are respectively arranged on opposite sides of the magnetic circuit system and connected to the housing. One end of the first voice coil is connected to the first diaphragm, and the other end of the first voice coil is suspended in the first magnetic gap. One end of the second voice coil is connected to the second diaphragm, and the other end of the second voice coil is suspended in the second magnetic gap. Thus, when an electric current is passed through the first voice coil and the second voice coil, the first voice coil and the second voice coil respectively convert electrical energy into mechanical energy in the first magnetic gap and the second magnetic gap formed by the magnetic circuit system, so as to drive the first voice coil and the second voice coil to drive the first diaphragm and the second diaphragm to vibrate respectively. Not only can sound be generated by driving two voice coils to drive two diaphragms to vibrate through one magnetic circuit system, but also the double-sided diaphragms can emit sound in the same direction without increasing the external dimensions, and the vibration area of the vibration system is increased, thereby achieving the purpose of performance improvement. Further, the magnetic circuit system is set as a central magnetic part, an edge magnetic part, an annular magnet, a magnetic yoke and a support member, and the magnetic yoke is set as a first top plate and a first bottom plate arranged at both ends of the annular magnet. The central magnetic part is arranged on the first top plate and spaced from the annular magnet to form a first magnetic gap. The edge magnetic part is arranged on the first bottom plate and spaced from the annular magnet to form a second magnetic gap. A support member is arranged on the side of the first top plate of the magnetic yoke facing away from the central magnetic part. Thus, the inner periphery of the second diaphragm is connected and fixed by the support member, and an air flow cavity is formed by enclosing the support member and the magnetic yoke. A first through hole communicating the first magnetic gap and the air flow cavity is provided on the first top plate of the magnetic yoke. The support member is provided with a second through hole communicating the air flow cavity, and a third through hole communicating the second through hole is provided on the inner periphery of the second diaphragm. Thus, the sound wave on the first side facing the first diaphragm radiates outward through the first magnetic gap, the first through hole, the air flow cavity, the second through hole and the third through hole. At the same time, by providing a through hole communicating the air flow cavity in the magnetic circuit system, the through hole sequentially penetrates through the central magnetic part and the first top plate of the magnetic yoke. Thus, the sound wave on the first side facing the first diaphragm can further radiate outward through the through hole, the air flow cavity, the second through hole and the third through hole. Thus, the sound waves on the first side facing the first diaphragm and the second diaphragm jointly radiate to the first side of the sound generating device, which is beneficial to the superposition of the compressed air when the first diaphragm and the second diaphragm vibrate, and improves the loudness and sensitivity of the sound generating device. And the second diaphragm and the central magnetic part are respectively installed and fixed by the support member and the magnetic yoke to improve the installation stability, thereby reducing the reliability risk. And through the first through hole of the magnetic yoke and the through hole of the magnetic circuit system respectively cooperating with the air flow cavity formed by the first top plate of the magnetic yoke and the support member, the air flow circulation area when the first diaphragm vibrates is effectively increased, so as to ensure that the air flow circulates more smoothly, improve the high-frequency performance of the first diaphragm, and thus improve the high-frequency performance after the superposition of the first diaphragm and the second diaphragm;Meanwhile, the magnetic yoke is set as a split structure, and an annular magnet is provided such that the first top plate and the first bottom plate of the magnetic yoke are respectively connected to both ends of the annular magnet. In this way, the first magnetic gap and the second magnetic gap located on opposite sides of the annular magnet can be formed by the cooperation of the annular magnet with the central magnetic part and the edge magnetic part respectively, thereby increasing the magnet volume of the magnetic circuit system and enhancing the magnetic field intensity to effectively improve the driving force of the first magnetic gap and the second magnetic gap on the first voice coil and the second voice coil and increase the BL value. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the structures shown in these drawings without creative efforts.

[0045] Figure 1 Schematic structural diagram of an embodiment of the sound generating device provided by the present invention;

[0046] Figure 2 Schematic structural diagram of another perspective of an embodiment of the sound generating device provided by the present invention;

[0047] Figure 3 Exploded view of an embodiment of the sound generating device provided by the present invention;

[0048] Figure 4 Cross-sectional view of an embodiment of the sound generating device provided by the present invention;

[0049] Figure 5 Partial cross-sectional view of another embodiment of the sound generating device provided by the present invention;

[0050] Figure 6 Top view structural diagram of an embodiment of the sound generating device provided by the present invention with the front cover removed;

[0051] Figure 7 Exploded view of the housing of an embodiment of the sound generating device provided by the present invention;

[0052] Figure 8 Exploded view of the connection of the magnetic yoke with the annular magnet and the support member in an embodiment of the present invention;

[0053] Figure 9 Cross-sectional view of the connection of the magnetic yoke with the annular magnet and the support member in an embodiment of the present invention;

[0054] Figure 10 Schematic structural diagram of the front cover in an embodiment of the sound generating device provided by the present invention;

[0055] Figure 11 Schematic structural diagram of an embodiment of the electronic device provided by the present invention;

[0056] Figure 12 Schematic cross-sectional view of an embodiment of the electronic device provided by the present invention.

[0057] Explanation of the reference numerals in the drawings:

[0058] 100, sound generating device; 1, housing; 11, first housing; 111, first leakage hole; 112, support platform; 113, support boss; 114, retaining wall; 12, second housing; 121, leakage channel; 13, first cavity; 2, magnetic circuit system; 21, magnetic yoke; 211, first top plate; 2111, protruding portion; 2112, support portion; 2113, inclined surface; 2114, first through hole; 2115, air flow channel; 212, first bottom plate; 2121, avoidance groove; 22, central magnetic part; 221, central magnet; 222, central magnetic guide plate; 23, side magnetic part; 231, side magnet; 232, side magnetic guide plate; 24, support member; 241, air flow cavity; 242, second top plate; 2421, second through hole; 243, second side plate; 244, second bottom plate; 25, first magnetic gap; 26, second magnetic gap; 27, through hole; 28, ring magnet; 3, vibration system; 31, first diaphragm; 311, folding ring portion; 312, dome; 32, second diaphragm; 321, inner folding ring; 322, vibrating portion; 323, outer folding ring; 324, third through hole; 325, vibrating plate; 33, first voice coil; 34, second voice coil; 41, first positioning ring; 42, second positioning ring; 6, front cover; 61, second cavity; 62, fourth through hole; 63, top cover portion; 64, side plate portion; 65, edge portion; 66, bent portion; 67, limiting space; 700, device housing; 710, receiving cavity; 720, sound outlet hole; 730, second leakage hole; 740, front cavity; 750, rear cavity; 800, electronic device.

[0059] The realization, functional features and advantages of the object of the present invention will be further described in conjunction with the embodiments with reference to the drawings. Detailed implementation manners

[0060] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0061] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship, movement conditions, etc. between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0062] At the same time, the meaning of "and / or" or "and / or" that appears throughout the text is to include three scenarios. Taking "A and / or B" as an example, it includes scenario A, or scenario B, or the scenario where both A and B are satisfied simultaneously.

[0063] In addition, in the present invention, descriptions such as "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0064] In recent years, with the rapid development of consumer electronic products, electronic devices such as headphones, smartphones, VR devices, etc. have been recognized by consumers and widely used. Those skilled in the art have also correspondingly improved related supporting products such as headphones to meet the performance requirements of electronic products and the needs of consumers for product performance.

[0065] The sound generating device is an important electro-acoustic transducer component in consumer electronic products and is widely used as a speaker, earpiece, headphone, etc. With the improvement of the performance of electronic products, the improvement of the acoustic performance of the sound generating device is also an inevitable trend. In particular, the requirements for OWS (Open Wearable Stereo, fully open wearable headphones) Bluetooth headsets are different from those of TWS (True Wireless Stereo, true wireless stereo). Because the whole machine aims to reflect the convenience and comfort of wearing, it adopts a non-in-ear method, so the improvement of the performance of the sound generating device is extremely urgent.

[0066] Traditional Driver designs all vibrate and generate sound unidirectionally. In the cavity of the whole machine with limited internal space, it is very difficult to increase the vibration area and vibration displacement in the design. Therefore, the room for improving the performance of the sound generating device is relatively limited, and it cannot meet the requirements of existing wearable audio products such as OWS. At the same time, in order to improve the performance of the sound generating device, the product design is becoming more and more extreme, and the space utilization rate is also getting higher and higher, resulting in risks in the reliability of the product and being not conducive to the improvement of high-frequency performance, thus making the performance and effect of the whole machine poor.

[0067] Based on the above concept and problem, the present invention provides a sound generating device 100. It can be understood that the sound generating device 100 is applied to an electronic device, and the electronic device can be a mobile phone, earphone, smart wearable device, etc., which is not limited herein.

[0068] In this embodiment, the sound generating device 100 of the present invention is provided with a double diaphragm and a double voice coil structure, and uses a magnetic circuit system 2 to drive two voice coils to drive two diaphragms to vibrate to generate sound. At the same time, without increasing the external dimensions, the double-sided diaphragm generates sound, increasing the vibration area of the vibration system 3, so as to achieve the purpose of performance improvement. And the double-sided diaphragms radiate sound waves on the same side of the sound generating device 100, which is beneficial to improving the loudness and sensitivity of the sound generating device 100, and increasing the magnet volume of the magnetic circuit system 2 to improve the magnetic field strength and effectively improve the BL value.

[0069] Please refer to Figures 1 to 10As shown in the figure, in the embodiment of the present invention, the sound generating device 100 includes a housing 1, a magnetic circuit system 2 and a vibration system 3. The magnetic circuit system 2 is connected to the housing 1. The magnetic circuit system 2 includes a central magnetic part 22, an edge magnetic part 23, a ring magnet 28, a magnetic yoke 21 and a support member 24. The magnetic yoke 21 includes a first top plate 211 and a first bottom plate 212 provided at both ends of the ring magnet 28. The central magnetic part 22 is provided on the first top plate 211 and is spaced from the ring magnet 28 to form a first magnetic gap 25. The edge magnetic part 23 is provided on the first bottom plate 212 and is spaced from the ring magnet 28 to form a second magnetic gap 26. The second magnetic gap 26 is arranged around the first magnetic gap 25. The support member 24 is provided on the side of the first top plate 211 facing away from the central magnetic part 22 and encloses with the first top plate 211 to form an air flow cavity 241. The first top plate 211 is provided with a first through hole 2114 communicating the first magnetic gap 25 and the air flow cavity 241. The support member 24 is provided with a second through hole 2421 communicating the air flow cavity 241. The magnetic circuit system 2 is further provided with a through hole 27 sequentially penetrating the central magnetic part 22 and the first top plate 211. The through hole 27 is communicated with the air flow cavity 241. The vibration system 3 includes a first diaphragm 31, a second diaphragm 32, a first voice coil 33 and a second voice coil 34. The first diaphragm 31 and the second diaphragm 32 are located on opposite sides of the magnetic circuit system 2. The outer periphery of the first diaphragm 31 is connected to the housing 1 and is opposite to and spaced from the magnetic circuit system 2. The outer periphery of the second diaphragm 32 is connected to the housing 1. The inner periphery of the second diaphragm 32 is connected to the support member 24. And the inner periphery of the second diaphragm 32 is provided with a third through hole 324 communicating the second through hole 2421. One end of the first voice coil 33 is connected to the first diaphragm 31, and the other end of the first voice coil 33 is suspended in the first magnetic gap 25. One end of the second voice coil 34 is connected to the second diaphragm 32, and the other end of the second voice coil 34 is suspended in the second magnetic gap 26. Wherein, the sound generating device 100 has a first side of the second diaphragm 32 facing away from the first diaphragm 31 and a second side of the first diaphragm 31 facing away from the second diaphragm 32. The sound wave of the first diaphragm 31 facing the first side is radiated outward through the through hole 27, the air flow cavity 241, the second through hole 2421 and the third through hole 324, and at the same time is radiated outward through the first magnetic gap 25, the first through hole 2114, the air flow cavity 241, the second through hole 2421 and the third through hole 324, and jointly radiates to the first side with the sound wave of the second diaphragm 32 facing the first side.

[0070] In this embodiment, the sound generating device 100 can be a sound generating unit of a speaker, and the speaker can be a micro speaker. It should be noted that the magnetic circuit system 2 and the vibration system 3 of the sound generating device 100 are arranged oppositely.

[0071] It can be understood that the housing 1 is used to install, fix and support components such as the magnetic circuit system 2 and the vibration system 3, that is, the housing 1 provides an installation basis for components such as the magnetic circuit system 2 and the vibration system 3. Optionally, the housing 1 can be an integral structure or a combination of multiple split structures, which is not limited herein.

[0072] In this embodiment, the housing 1 can be optionally a box or a frame structure, that is, the housing 1 has a cavity with openings at both ends. The magnetic circuit system 2 is received in the cavity of the housing 1 and is connected to the housing 1. The first diaphragm 31 and the second diaphragm 32 of the vibration system 3 are respectively arranged on opposite sides of the magnetic circuit system 2, and the outer peripheries of the first diaphragm 31 and the second diaphragm 32 are respectively connected to both ends of the housing 1. In this way, a double-diaphragm structure is formed, so that two voice coils of the vibration system 3 are driven by one magnetic circuit system 2 to drive the two diaphragms to vibrate to generate sound. At the same time, without increasing the external dimensions, the two-sided diaphragms can generate sound in the same direction, and the vibration area of the vibration system 3 is increased, so as to achieve the purpose of performance improvement.

[0073] In this embodiment, the housing 1 is provided with conductive terminals, and both the first voice coil 33 and the second voice coil 34 are electrically connected to the conductive terminals. In this way, it is convenient for the sound generating device 100 to connect and conduct the first voice coil 33 and the second voice coil 34 to an external circuit through the conductive terminals.

[0074] It should be noted that the sound generating device 100 has a first side and a second side facing away from each other, and the first side and the second side can be understood in terms of orientation or direction. In this embodiment, as Figures 1 to 4 shown, the sound generating device 100 has a first side where the second diaphragm 32 faces away from the first diaphragm 31 and a second side where the first diaphragm 31 faces away from the second diaphragm 32.

[0075] Optionally, the sound waves of the first diaphragm 31 facing the first side and the sound waves of the second diaphragm 32 facing the first side are radiated together to the first side. In this way, the sound waves of the second diaphragm 32 and the sound waves of the first diaphragm 31 in the vibration system 3 can be superimposed to generate sound, so as to improve the sound generating effect and performance. In this embodiment, the first diaphragm 31 and the second diaphragm 32 can be optionally vibrated in the same direction and radiate sound waves with the same phase, so as to increase the volume of the sound generating device 100.

[0076] In this embodiment, the housing 1 is used to receive and fix structures such as the vibration system 3 and the magnetic circuit system 2. In this way, the sound generating device 100 can be used as an independent component in an electronic device or a sound generating module, which is not limited herein. It can be understood that the outer contour of the sound generating device 100 can be circular or square, so that the outer contours of the housing 1, the magnetic circuit system 2 and the vibration system 3 are correspondingly set to be circular or square, which is designed according to actual needs and is not limited herein.

[0077] Optionally, the housing 1 has a cylindrical structure, that is, both ends of the housing 1 have openings and are in the shape of a circular cylinder with openings at both ends. The outer peripheral contours of the first diaphragm 31 and the second diaphragm 32 of the vibration system 3 are substantially aligned and are similar to the outer contour of the housing 1. The first diaphragm 31 and the second diaphragm 32 are respectively connected to the openings at both ends of the housing 1, and the magnetic circuit system 2 is disposed in the cavity of the housing 1 and is located between the first diaphragm 31 and the second diaphragm 32. This facilitates the regular design of the shape of the sound generating device 100 and further facilitates its assembly into the whole machine, simplifying the reserved structure of the whole machine.

[0078] In this embodiment, as Figures 1 to 5 , Figure 7 shown, the housing 1 includes a first housing 11 and a second housing 12 connected to each other. The side of the first housing 11 facing away from the second housing 12 is connected to the outer peripheral edge of the first diaphragm 31, and one end of the second housing 12 away from the first housing 11 is connected to the outside of the second diaphragm 32. The outer peripheral edge of the first bottom plate 212 of the magnetic yoke 21 is connected to the side of the first housing 11 facing away from the first diaphragm 31.

[0079] It can be understood that the first housing 11 and the second housing 12 of the housing 1 are optionally cylindrical, so that the first housing 11 and the second housing 12 are adaptively connected to form the cylindrical housing 1. By designing the housing 1 as a split first housing 11 and second housing 12, the first diaphragm 31 can be assembled through the first housing 11, and the second diaphragm 32 can be assembled through the second housing 12, which facilitates the assembly of the sound generating device 100 during the assembly process. In this embodiment, the first housing 11 and the second housing 12 of the housing 1 are respectively provided with conductive terminals, which further facilitates the electrical connection of the first voice coil 33 and the second voice coil 34 to the external circuit, etc.

[0080] In one embodiment, the first housing 11 is provided with a first conductive member. One end of the first conductive member is electrically connected to the lead of the first voice coil 33. The second housing 12 is provided with a second conductive member. One end of the second conductive member is electrically connected to the lead of the second voice coil 34. The other end of the first conductive member is connected to the other end of the second conductive member for connection to an external circuit.

[0081] It can be understood that by respectively providing the first conductive member and the second conductive member on the first housing 11 and the second housing 12, the first conductive member and the second conductive member are respectively electrically connected to the leads of the first voice coil 33 and the second voice coil 34. In this way, the external circuit can be connected and conducted to the first voice coil 33 and the second voice coil 34 through the first conductive member and the second conductive member.

[0082] Optionally, the other end of the first conductive member is connected to the other end of the second conductive member. In this way, the first conductive member and the second conductive member can be connected and conducted to the external circuit as an integral structure, thereby simplifying the circuit connection structure and improving the assembly efficiency.

[0083] In this embodiment, by providing a first magnetic gap 25 and a second magnetic gap 26 on the magnetic circuit system 2, the second magnetic gap 26 is arranged to surround the first magnetic gap 25. In this way, it is convenient for the first voice coil 33 and the second voice coil 34 of the vibration system 3 to correspond to the first magnetic gap 25 and the second magnetic gap 26 respectively, and conductive terminals are provided on the housing 1 so that both the first voice coil 33 and the second voice coil 34 are electrically connected to the conductive terminals. Thus, when currents are passed through the first voice coil 33 and the second voice coil 34, the first voice coil 33 and the second voice coil 34 respectively convert electrical energy into mechanical energy in the first magnetic gap 25 and the second magnetic gap 26 formed by the magnetic circuit system 2, so as to drive the first voice coil 33 and the second voice coil 34 to drive the first diaphragm 31 and the second diaphragm 32 to vibrate respectively. Not only can sound be produced by driving two voice coils to drive two diaphragms to vibrate through one magnetic circuit system 2, but also the double-sided diaphragms can emit sound in the same direction without increasing the external dimensions, and the vibration area of the vibration system 3 is increased, thereby achieving the purpose of performance improvement.

[0084] It can be understood that the magnetic circuit system 2 is set as a central magnetic part 22, a side magnetic part 23, a ring magnet 28, a magnetic yoke 21 and a support member 24, and the magnetic yoke 21 is set as a split structure. The first top plate 211 and the first bottom plate 212 of the magnetic yoke 21 are arranged at both ends of the ring magnet 28, and the support member 24 is arranged on the side of the first top plate 211 of the magnetic yoke 21 facing away from the central magnetic part 22. Thus, the second diaphragm 32 and the central magnetic part 22 are fixed by the support member 24 and the first top plate 211 of the magnetic yoke 21 respectively. In this way, the connection area between the support member 24 and the inner edge of the second diaphragm 32 and the connection area between the central magnetic part 22 and the first top plate 211 of the magnetic yoke 21 can be increased. While improving the stability, the reliability risk is reduced. At the same time, a ring magnet 28 is arranged between the first top plate 211 and the first bottom plate 212 of the magnetic yoke 21, so that the central magnetic part 22 is connected to the first top plate 211 and is spaced from the ring magnet 28 to enclose a first magnetic gap 25. The side magnetic part 23 is arranged on the first bottom plate 212 and is spaced from the ring magnet 28 to enclose a second magnetic gap 26. That is, the side magnetic part 23 and the central magnetic part 22 are located on opposite sides of the ring magnet 28. In this way, the first magnetic gap 25 and the second magnetic gap 26 located on opposite sides of the ring magnet 28 can be formed by the cooperation of the ring magnet 28 with the side magnetic part 23 and the central magnetic part 22 respectively, thereby increasing the magnet volume of the magnetic circuit system 2, increasing the magnetic field strength, and effectively improving the driving force of the first magnetic gap 25 and the second magnetic gap 26 on the first voice coil 33 and the second voice coil 34 and improving the BL value.

[0085] In order to achieve that the sound waves on the first side of the first diaphragm 31 and the sound waves on the first side of the second diaphragm 32 are radiated to the first side together, and the sound waves are superimposed and enhanced to improve the high-frequency performance. In this embodiment, by providing a first through hole 2114 on the first top plate 211 of the magnetic yoke 21 to communicate the first magnetic gap 25 and the air flow cavity 241, and providing a second through hole 2421 communicating with the air flow cavity 241 on the support member 24, and further providing a through hole 27 that sequentially penetrates the central magnetic portion 22 and the first top plate 211 in the magnetic circuit system 2, such that the through hole 27 communicates with the air flow cavity 241, and connecting and fixing the inner peripheral edge of the second diaphragm 32 to the support member 24, and providing a third through hole 324 communicating with the second through hole 2421 at the inner peripheral edge of the second diaphragm 32, so that the sound waves on the first side of the first diaphragm 31 are radiated outward through the through hole 27, the air flow cavity 241, the second through hole 2421, and the third through hole 324, and at the same time are radiated outward through the first magnetic gap 25, the first through hole 2114, the air flow cavity 241, the second through hole 2421, and the third through hole 324, and are radiated to the first side together with the sound waves on the first side of the second diaphragm 32.

[0086] Optionally, the annular magnet 28 extends along the vibration direction of the vibration system 3, and the first top plate 211 and the first bottom plate 212 are connected to both ends of the annular magnet 28 along the vibration direction of the vibration system 3. It can be understood that the first top plate 211 and the first bottom plate 212 of the magnetic yoke 21 are distributed vertically along the vibration direction of the vibration system 3, that is, there is a height difference between the first top plate 211 and the first bottom plate 212 in the vibration direction of the vibration system 3, so as to ensure that the size of the magnetic circuit system 2 along the vibration direction of the vibration system 3 is not too large, thereby realizing a thin and light design.

[0087] The sound generating device 100 of the present invention houses a magnetic circuit system 2 and a vibration system 3 in a housing 1, and a first magnetic gap 25 and a second magnetic gap 26 are provided on the magnetic circuit system 2, such that the second magnetic gap 26 is disposed around the first magnetic gap 25. The vibration system 3 is configured as a first diaphragm 31, a second diaphragm 32, a first voice coil 33 and a second voice coil 34, such that the first diaphragm 31 and the second diaphragm 32 are respectively disposed on opposite sides of the magnetic circuit system 2 and connected to the housing 1. One end of the first voice coil 33 is connected to the first diaphragm 31, the other end of the first voice coil 34 is suspended in the first magnetic gap 25, one end of the second voice coil 34 is connected to the second diaphragm 32, and the other end of the second voice coil 34 is suspended in the second magnetic gap 26. Thus, when currents are passed through the first voice coil 33 and the second voice coil 34, the first voice coil 33 and the second voice coil 34 respectively convert electrical energy into mechanical energy in the first magnetic gap 25 and the second magnetic gap 26 formed by the magnetic circuit system 2, so as to drive the first voice coil 33 and the second voice coil 34 to drive the first diaphragm 31 and the second diaphragm 32 to vibrate respectively. Not only can sound be generated by driving two voice coils to drive two diaphragms to vibrate through one magnetic circuit system 2, but also the same-direction sound emission of the double-sided diaphragms can be achieved without increasing the external dimensions, and the vibration area of the vibration system 3 is increased, thereby achieving the purpose of performance improvement;Further, by setting the magnetic circuit system 2 as the central magnetic part 22, the edge magnetic part 23, the annular magnet 28, the magnetic yoke 21 and the support 24, and setting the magnetic yoke 21 as the first top plate 211 and the first bottom plate 212 provided at both ends of the annular magnet 28, the central magnetic part 22 is provided on the first top plate 211 and is spaced from the annular magnet 28 to form a first magnetic gap 25, the edge magnetic part 23 is provided on the first bottom plate 212 and is spaced from the annular magnet 28 to form a second magnetic gap 26, and a support 24 is provided on the side of the first top plate 211 of the magnetic yoke 21 facing away from the central magnetic part 22. Thus, the inner periphery of the second diaphragm 32 is connected and fixed by the support 24, and an air flow cavity 241 is formed by enclosing the support 24 and the first top plate 211 of the magnetic yoke 21. A first through hole 2114 communicating the first magnetic gap 25 and the air flow cavity 241 is provided on the first top plate 211 of the magnetic yoke 21, a second through hole 2421 communicating the air flow cavity 241 is provided on the support 24, and a third through hole 324 communicating the second through hole 2421 is provided on the inner periphery of the second diaphragm 32. In this way, the sound wave on the first side facing the first diaphragm 31 is radiated outward through the first magnetic gap 25, the first through hole 2114, the air flow cavity 241, the second through hole 2421 and the third through hole 324. At the same time, by providing a through hole 27 communicating the air flow cavity 241 in the magnetic circuit system 2, the through hole 27 sequentially penetrates the central magnetic part 22 and the first top plate 211 of the magnetic yoke 21. In this way, the sound wave on the first side facing the first diaphragm 31 can be further radiated outward through the through hole 27, the air flow cavity 241, the second through hole 2421 and the third through hole 324. Thus, the sound waves on the first side facing the first diaphragm 31 and the second diaphragm 32 are jointly radiated to the first side of the sound generating device 100, which is beneficial to the superposition of the compressed air when the first diaphragm 31 and the second diaphragm 32 vibrate, and improves the loudness and sensitivity of the sound generating device 100; and the support 24 and the magnetic yoke 21 are respectively used to install and fix the second diaphragm 32 and the central magnetic part 22 to improve the installation stability, thereby reducing the reliability risk. Moreover, through the first through hole 2114 of the first top plate 211 and the through hole 27 of the magnetic circuit system 2, the air flow cavity 241 formed by the first top plate 211 of the magnetic yoke 21 and the support 24 is effectively increased, and the air flow area when the first diaphragm 31 vibrates is effectively increased, so as to ensure smoother air flow and improve the high-frequency performance of the first diaphragm 31, thereby improving the high-frequency performance after the superposition of the first diaphragm 31 and the second diaphragm 32; at the same time, the magnetic yoke 21 is set as a split structure, and the annular magnet 28 is provided, so that the first top plate 211 and the first bottom plate 212 of the magnetic yoke 21 are respectively connected to both ends of the annular magnet 28. In this way, the first magnetic gap 25 and the second magnetic gap 26 located on opposite sides of the annular magnet 28 can be formed by the cooperation of the annular magnet 28 with the central magnetic part 22 and the edge magnetic part 23 respectively, thereby increasing the magnet volume of the magnetic circuit system 2 and increasing the magnetic field strength, so as to effectively improve the driving force of the first magnetic gap 25 and the second magnetic gap 26 on the first voice coil 33 and the second voice coil 34 and improve the BL value.;

[0088] When the sound generating device 100 of the present application is actually used, there can be various application environments. In one embodiment, the first diaphragm 31 and the second diaphragm 32 vibrate in the same direction. The first diaphragm 31 and the second diaphragm 32 radiate a first sound wave to the external environment on the first side, and the first diaphragm 31 and the second diaphragm 32 radiate a second sound wave to the external environment on the second side. The first sound wave and the second sound wave have opposite phases. In this way, both the first side and the second side of the sound generating device 100 communicate with the external environment, and the sound waves on both sides radiate sound waves with opposite phases to the external environment. The sound waves on both sides cancel each other out in the far field, which is suitable for environments that require far-field noise cancellation and privacy protection.

[0089] In one embodiment, the sound generating device 100 is applied to an electronic device 800 and is used to divide the space of the electronic device 800 into an acoustically isolated front cavity 740 and a rear cavity 750. The first side communicates with the front cavity 740, the second side communicates with the rear cavity 750, the first diaphragm 31 and the second diaphragm 32 vibrate in the same direction, and radiate a first sound wave to the front cavity 740 and a second sound wave to the rear cavity 750. The first sound wave and the second sound wave have opposite phases.

[0090] It can be understood that the first side of the first diaphragm 31 and the second diaphragm 32 communicates with the front cavity 740, and the second side of the first diaphragm 31 and the second diaphragm 32 communicates with the rear cavity 750. The electronic device 800 usually has a sound outlet hole 720 for the sound wave of the front cavity 740 to radiate out. When the electronic device 800 is used, the sound wave of the front cavity 740 can be radiated out through the sound outlet hole 720 and received by the user. Further, the sound wave of the rear cavity 750 is optionally radiated out through a rear leakage hole (the second leakage hole 730 in the present application). In this way, the sound waves of the front cavity 740 and the rear cavity 750 can form a sound dipole, achieving the technical effect of reducing sound leakage. Or, the sound wave of the rear cavity 750 can not be radiated outwards. The sound generating device 100 of the present application only plays the role of enhancing the superposition of the sound waves on the first side of the first diaphragm 31 and the second diaphragm 32, improving the high-frequency performance. It is selected according to the actual situation.

[0091] In one embodiment, a first cavity 13 is formed between the second diaphragm 32, the housing 1, the annular magnet 28, the magnetic yoke 21 and the support member 24. The housing 1 is provided with a first leakage hole 111 communicating the first cavity 13 with the outside; wherein, the sound wave of the second diaphragm 32 facing the second side is radiated outwards through the first leakage hole 111 and radiates to the second side together with the sound wave of the first diaphragm 31 facing the second side.

[0092] In this embodiment, as Figure 4As shown, the first cavity 13 can be optionally a sealed cavity. To balance the air pressure in the first cavity 13 and improve the vibration balance of the second diaphragm 32. It can be understood that by providing a first leakage hole 111 on the sound generating device 100 that communicates the first cavity 13 with the outside, the first leakage hole 111 is used to release air, adjust the air pressure in the first cavity 13, balance the air pressure on both sides of the second diaphragm 32, and improve the vibration stability of the second diaphragm 32.

[0093] To enable the sound waves on the second side of the second diaphragm 32 and the sound waves on the second side of the first diaphragm 31 to be radiated together to the second side. In this embodiment, the housing 1 is provided with a first leakage hole 111 that communicates the first cavity 13 with the outside. The sound waves on the second side of the second diaphragm 32 are radiated outward through the first leakage hole 111 and are radiated together with the sound waves on the second side of the first diaphragm 31 to the second side.

[0094] Optionally, the housing 1 is provided with a first leakage hole 111 that communicates the first cavity 13 with the outside. The first leakage hole 111 penetrates the surface of the housing 1 facing the second side. In this way, the sound waves on the second side of the second diaphragm 32 are radiated outward through the first leakage hole 111 and are radiated together with the sound waves on the second side of the first diaphragm 31 to the second side. At the same time, it is convenient to assemble the sound generating device 100, and it is possible to avoid blocking the first leakage hole 111 during the assembly process. It is also convenient to provide structures such as a breathable member at the first leakage hole 111, simplifying the assembly difficulty.

[0095] In this embodiment, the sound waves on the first side of the first diaphragm 31 and the sound waves on the first side of the second diaphragm 32 are radiated together to the first side as the first sound wave, and the sound waves on the second side of the second diaphragm 32 and the sound waves on the second side of the first diaphragm 31 are radiated together to the second side as the second sound wave. Optionally, the first sound wave and the second sound wave have opposite phases.

[0096] Optionally, the first leakage hole 111 includes a plurality of holes. In this embodiment, the plurality of first leakage holes 111 are symmetrically arranged along the circumference of the sound generating device 100. In this way, the air pressure in the first cavity 13 is balanced by the first leakage hole 111, and the vibration balance of the second diaphragm 32 is improved.

[0097] In one embodiment, the sound generating device 100 further includes a first breathable member that covers the first leakage hole 111.

[0098] It can be understood that by providing a first air-permeable member on the first leakage hole 111 to cover the first leakage hole 111, on the one hand, it can prevent external dust or impurities from entering the interior of the sound generating device 100, thereby avoiding affecting the acoustic performance of the sound generating device 100; on the other hand, it can further adjust the air flow rate in the first cavity 13, adjust the air pressure in the first cavity 13, balance the air pressure on both sides of the second diaphragm 32, and improve the vibration stability of the second diaphragm 32.

[0099] In one embodiment, the housing 1 includes a first housing 11 and a second housing 12 connected to each other. One end of the first housing 11 away from the second housing 12 is connected to the outer periphery of the first diaphragm 31, and one side of the second housing 12 facing away from the first housing 11 is connected to the outer periphery of the second diaphragm 32. The outer periphery of the first bottom plate 212 is connected to the first housing 11.

[0100] Optionally, the first housing 11 is provided with a first leakage hole 111. The first leakage hole 111 penetrates the surface of the first housing 11 facing the second side, and the first leakage hole 111 is located outside the first diaphragm 31. It can be understood that with such a setting, the sound wave of the second diaphragm 32 facing the second side can be radiated outward through the first leakage hole 111 and superimposed with the sound wave of the first diaphragm 31 facing the second side to radiate toward the second side together, so as to achieve the superposition of the air compressed when the first diaphragm 31 and the second diaphragm 32 jointly release air or vibrate toward the second side, improve the loudness and sensitivity of the sound generating device 100, and reduce the assembly difficulty and increase the adaptability of the overall machine assembly.

[0101] Of course, in other embodiments, the side wall of the first housing 11 or the second housing 12 is provided with a first leakage hole 111; or, a first leakage hole 111 is formed at the connection between the first housing 11 and the second housing 12, which is not limited herein.

[0102] It can be understood that by providing the first leakage hole 111 and providing a first air-permeable member on the first leakage hole 111, the air flow rate in the cavity of the sound generating device 100 can be further adjusted and the acoustic resistance can be adjusted, thereby improving the performance of the sound generating device 100.

[0103] In one embodiment, a support platform 112 is convexly provided on the inner wall of the first housing 11. The outer periphery of the first bottom plate 212 and the outer periphery of the first diaphragm 31 are respectively provided on both sides of the support platform 112, and a first leakage hole 111 is formed between the inner wall of the first housing 11 and the support platform 112.

[0104] In this embodiment, as Figures 3 to 5 、 Figure 7As shown, by providing a support platform 112 on the inner wall of the first housing 11 of the outer housing 1, the outer periphery of the first bottom plate 212 of the magnetic yoke 21 and the outer periphery of the first diaphragm 31 are fixed by means of the support platform 112 at the same time. That is, the outer periphery of the first bottom plate 212 and the outer periphery of the first diaphragm 31 are respectively disposed on both sides of the support platform 112.

[0105] It can be understood that a first leakage hole 111 is formed between the inner wall of the first housing 11 and the support platform 112. In this way, it can be ensured that the first leakage hole 111 penetrates the surface of the first housing 11 facing the second side, so that the first leakage hole 111 and the first diaphragm 31 are both located on the second side of the sound generating device 100, which is beneficial to simplifying the assembly difficulty and enabling the first diaphragm 31 to avoid the first leakage hole 111 of the first housing 11. Optionally, the outer contour of the support platform 112 is similar to the outer contour of the first diaphragm 31.

[0106] In an embodiment, the edge magnetic part 23 includes a stacked edge magnet 231 and an edge magnetic conductive plate 232. The edge magnet 231 is connected to the first bottom plate 212, the edge magnetic conductive plate 232 is connected to the second housing 12, and a leakage channel 121 communicating with the first leakage hole 111 is formed between the edge magnetic conductive plate 232 and the second housing 12.

[0107] In this embodiment, the edge magnetic conductive plate 232 and the second housing 12 can be integrally formed. It can be understood that the first housing 11 can be a plastic housing, and the outer periphery of the magnetic yoke 21 is integrally injection molded with the first housing 11, so that the processing steps and assembly steps can be simplified. Of course, in other embodiments, the edge magnetic conductive plate 232 and the second housing 12 can be adhesively connected, that is, the outer periphery of the magnetic yoke 21 and the first housing 11 can also be adhesively connected. As Figure 4 、 Figure 5 As shown, the outer periphery of the magnetic yoke 21 is adhesively connected to the support platform 112.

[0108] It can be understood that by forming a leakage channel 121 between the edge magnetic conductive plate 232 of the edge magnetic part 23 and the second housing 12, the first cavity 13 can communicate with the first leakage hole 111 through the leakage channel 121, so as to ensure the smoothness of the air flow in the first cavity 13 and ensure that the first leakage hole 111 and the first diaphragm 31 are both located on the second side of the sound generating device 100, which is beneficial to simplifying the assembly difficulty and enabling the first diaphragm 31 to avoid the first leakage hole 111 of the first housing 11.

[0109] In this embodiment, by disposing the support member 24 on the side of the first top plate 211 of the magnetic yoke 21 facing away from the central magnetic portion 22, an air flow cavity 241 is formed by enclosing the support member 24 and the first top plate 211. A second through hole 2421 is provided in the support member 24, and a first through hole 2114 communicating the first magnetic gap 25 and the air flow cavity 241 is provided in the first top plate 211. In this way, the sound waves on the first side of the first diaphragm 31 sequentially pass through the first through hole 2114, the air flow cavity 241, the second through hole 2421, and the third through hole 324 and radiate outward, that is, the first magnetic gap 25, the first through hole 2114, the air flow cavity 241, the second through hole 2421, and the third through hole 324 are sequentially connected to form an air flow channel. A through hole 27 communicating the air flow cavity 241 is provided in the magnetic circuit system 2, and the through hole 27 sequentially penetrates through the central magnetic portion 22 and the first top plate 211, so that the first through hole 2114 and the through hole 27 are simultaneously communicated with the air flow cavity 241. In this way, the sound waves on the first side of the first diaphragm 31 sequentially pass through the through hole 27, the air flow cavity 241, the second through hole 2421, and the third through hole 324 and radiate outward, that is, the through hole 27, the air flow cavity 241, the second through hole 2421, and the third through hole 324 are sequentially connected to form another air flow channel, thereby facilitating the sound waves on the first side of the first diaphragm 31 to radiate outward to the side of the second diaphragm 32 through the two air flow channels. In this way, the sound waves on the first side of the first diaphragm 31 and the second diaphragm 32 are radiated outward on the same side (i.e., the first side) of the sound generating device 100, which is beneficial to the superposition of the compressed air when the first diaphragm 31 and the second diaphragm 32 vibrate, and improves the loudness and sensitivity of the sound generating device 100.

[0110] It can be understood that the second diaphragm 32 and the central magnetic portion 22 are respectively installed and fixed by using the support member 24 and the first top plate 211 of the magnetic yoke 21 to improve the installation stability, thereby reducing the reliability risk. And through the first through hole 2114 of the magnetic yoke 21 and the through hole 27 of the magnetic circuit system 2, respectively cooperating with the air flow cavity 241 formed by the first top plate 211 and the support member 24, the air flow circulation area when the first diaphragm 31 vibrates is effectively increased, thereby ensuring smoother air flow circulation, improving the high-frequency performance of the first diaphragm 31, and thus improving the high-frequency performance after the superposition of the first diaphragm 31 and the second diaphragm 32.

[0111] In this embodiment, the first top plate 211 of the magnetic yoke 21 is a metal magnetic conductive plate. Optionally, the support member 24 is a metal part. It can be understood that the support member 24 and the first top plate 211 of the magnetic yoke 21 can be connected by bonding or welding, which is not limited herein. Of course, in other embodiments, the support member 24 can be selected as an injection molded part. The support member 24 and the first top plate 211 of the magnetic yoke 21 can be integrally injection molded, which is not limited herein.

[0112] In this embodiment, the through hole 27 penetrates through the central magnetic part 22 and the first top plate 211 in sequence. That is, the first top plate 211 is provided with a fifth through hole, and the central magnetic part 22 is provided with a sixth through hole corresponding to the fifth through hole. The sixth through hole and the fifth through hole are correspondingly communicated to form the through hole 27. It can be understood that the first top plate 211 is provided with a fifth through hole and a first through hole 2114.

[0113] In one embodiment, the number of the first through holes 2114 is one or more. In order to keep the air flow smooth and ensure the vibration balance of the first diaphragm 31. The number of the first through holes 2114 is at least 2. In specific applications, different numbers of the first through holes 2114 are set according to needs, and the first through holes 2114 are arranged at intervals. Optionally, the first through holes 2114 include a plurality, and the plurality of first through holes 2114 are arranged at intervals. In this embodiment, the plurality of first through holes 2114 are arranged around the central magnetic part 22 and are evenly and spaced apart.

[0114] In this embodiment, as Figure 3 , Figure 4 , Figure 8 and Figure 9 shown, by setting the magnetic yoke 21 as a split structure, the first top plate 211 and the first bottom plate 212 of the magnetic yoke 21 are located in different planes along the vibration direction of the vibration system 3, so that the first top plate 211 and the first bottom plate 212 of the magnetic yoke 21 are respectively connected to both ends of the ring magnet 28. That is, the ring magnet 28 is optionally arranged around the periphery of the first top plate 211 and is arranged at an angle with the first top plate 211, and the ring magnet 28 and the first top plate 211 enclose a receiving cavity. The central magnetic part 22 is arranged in the receiving cavity, is connected to the first top plate 211, and is spaced from the ring magnet 28 to enclose a first magnetic gap 25. The first bottom plate 212 is optionally connected to one end of the ring magnet 28 away from the first top plate 211, and the first bottom plate 212 extends in a direction away from the receiving cavity and is arranged at an angle with the ring magnet 28. The side magnetic part 23 is arranged on the first bottom plate 212 and is spaced from the ring magnet 28 to enclose a second magnetic gap 26. That is, the side magnetic part 23 and the central magnetic part 22 are located on opposite sides of the ring magnet 28.

[0115] In one embodiment, the area of the first top plate 211 is defined as S1, and the opening area of the through hole 27 is defined as S2, and S2=(10% - 80%)S1.

[0116] In this embodiment, by controlling the opening area of the fifth through hole on the first top plate 211, it is beneficial for the sound wave of the first diaphragm 31 to radiate to the outside, and the structural strength of the magnetic yoke 21 and the connection area between the central magnetic part 22 and the first top plate 211 can be ensured, thereby improving the stability.

[0117] Optionally, the opening area S2 of the through hole 27 (i.e., the fifth through hole on the first top plate 211) accounts for 10% - 80% of the area S1 of the first top plate 211. Specifically, it can be 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, etc., which is not limited herein.

[0118] It can be understood that if the opening area of the fifth through hole is too small, it is not conducive to the sound wave of the first diaphragm 31 radiating to the outside; if the area of the fifth through hole is too large, the bonding area between the central magnetic part 22 and the first top plate 211 is too small, which is not conducive to improving the connection reliability between the two.

[0119] It should be noted that the opening area of the first through hole 2114 on the first top plate 211 also affects the radiation of the sound wave of the first diaphragm 31 to the outside, that is, if the area of the first through hole 2114 is too small, it is not conducive to the sound wave of the first diaphragm 31 radiating to the outside; of course, if the area of the first through hole 2114 is too large, the bonding area between the central magnetic part 22 and the first top plate 211 is too small, which is not conducive to improving the connection reliability between the two.

[0120] It can be understood that by controlling the opening area of the first through hole 2114 on the first top plate 211, it is not only conducive to the sound wave of the first diaphragm 31 radiating to the outside, but also can ensure the structural strength of the magnetic yoke 21 and the connection area between the central magnetic part 22 and the first top plate 211, thereby improving the stability.

[0121] It should be noted that when there is one first through hole 2114, the opening area of the first through hole 2114 is the opening area of one first through hole 2114. When there are multiple first through holes 2114, the opening area of the first through hole 2114 is the sum of the opening areas of multiple first through holes 2114.

[0122] Optionally, the opening area of the first through hole 2114 accounts for 10% - 80% of the area of the first top plate 211. Specifically, it can be 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, etc., which is not limited herein.

[0123] In an embodiment, the central magnetic part 22 includes a centrally stacked magnet 221 and a central magnetic conductive plate 222. The central magnet 221 is connected to the convex portion 2111, and the through hole 27 sequentially penetrates through the central magnetic conductive plate 222, the central magnet 221, and the convex portion 2111.

[0124] In this embodiment, as Figure 4As shown, the through-hole 27 sequentially penetrates through the central magnetic portion 22 and the first top plate 211. The central magnetic portion 22 includes a centrally stacked magnet 221 and a central magnetic conductive plate 222, and the centrally stacked magnet 221 is connected to the first top plate 211. Optionally, the through-hole 27 sequentially penetrates through the central magnetic conductive plate 222, the centrally stacked magnet 221, and the first top plate 211.

[0125] It can be understood that the centrally stacked magnet 221 is connected to the first top plate 211 of the magnetic yoke 21, that is, the centrally stacked magnet 221 is clamped between the first top plate 211 and the central magnetic conductive plate 222, and the outer peripheral edges of the centrally stacked magnet 221 and the central magnetic conductive plate 222 are spaced from the annular magnet 28 to form a first magnetic gap 25.

[0126] Optionally, the centrally stacked magnet 221 and the central magnetic conductive plate 222 of the central magnetic portion 22 can be circular plate-shaped or disc-shaped structures, which are not limited herein. The sixth through-hole sequentially penetrates through the central magnetic conductive plate 222 and the centrally stacked magnet 221.

[0127] It can be understood that the central magnetic conductive plate 222 of the central magnetic portion 22 is provided with a first through-hole, and the centrally stacked magnet 221 is provided with a second through-hole. The first through-hole and the second through-hole correspond and communicate to form the sixth through-hole. The first top plate 211 is provided with a fifth through-hole, so that the first through-hole, the second through-hole (that is, the sixth through-hole), and the fifth through-hole correspond and communicate in sequence to form the through-hole 27.

[0128] Optionally, the first through-hole, the second through-hole, and the fifth through-hole are coaxially arranged along the vibration direction of the vibration system 3.

[0129] In this embodiment, the first through-hole 2114 of the first top plate 211 is spaced from the fifth through-hole. Optionally, there are multiple first through-holes 2114, and the multiple first through-holes 2114 are spaced and arranged around the fifth through-hole, which are not limited herein.

[0130] In order to further ensure the smooth flow of the air flow below the first diaphragm 31, improve the high-frequency performance of the first diaphragm 31, and further improve the high-frequency performance after the superposition of the first diaphragm 31 and the second diaphragm 32. In one embodiment, the first top plate 211 includes a convex portion 2111 and a support portion 2112 connected to each other. The convex portion 2111 protrudes from the first top plate 211 toward the central magnetic portion 22, so that the support portion 2112 surrounds the convex portion 2111; wherein, the support portion 2112 is provided with a first through-hole 2114, the central magnetic portion 22 is disposed on the convex portion 2111, and is spaced from the support portion 2112 to enclose an air flow channel 2115. The air flow channel 2115 communicates the first magnetic gap 25 and the first through-hole 2114. The support member 24 is connected to the side of the support portion 2112 facing away from the air flow channel 2115, and the through-hole 27 sequentially penetrates through the central magnetic portion 22 and the convex portion 2111.

[0131] In this embodiment, as Figure 3 , Figure 4 , Figure 8 , Figure 9 shown, by providing a convex portion 2111 protruding towards the central magnetic portion 22 on the first top plate 211 of the magnetic yoke 21, the central magnetic portion 22 is disposed on the convex portion 2111 and spaced apart from the support portion 2112 to enclose an air flow channel 2115, and a first through hole 2114 is provided in the support portion 2112. In this way, the air flow channel 2115 is used to connect the first magnetic gap 25 and the first through hole 2114, which can not only ensure the smooth air flow below the first diaphragm 31 and improve the high-frequency performance of the first diaphragm 31, but also ensure the magnet volume of the central magnetic portion 22, thereby ensuring the magnetic field strength.

[0132] It can be understood that the convex portion 2111 is located at the center of the first top plate 211, which is convenient for installing and fixing the central magnetic portion 22. The support portion 2112 is arranged around the convex portion 2111. In this way, a plurality of first through holes 2114 can be provided to ensure the smooth air flow below the first diaphragm 31. In this embodiment, the through hole 27 sequentially penetrates the central magnetic portion 22 and the convex portion 2111, that is, the through hole 27 sequentially penetrates the central magnetic guide plate 222, the central magnet 221 and the convex portion 2111, and the convex portion 2111 is provided with a fifth through hole.

[0133] In this embodiment, as Figure 3 , Figure 4 , Figure 8 , Figure 9 shown, an inclined surface 2113 is formed at the connection between the convex portion 2111 and the support portion 2112, and the first through hole 2114 sequentially penetrates the support portion 2112 and the inclined surface 2113. It can be understood that the convex portion 2111 is recessed from the side of the first top plate 211 of the magnetic yoke 21 facing the support 24 towards the direction away from the support 24, so that the side of the first top plate 211 facing the central magnetic portion 22 protrudes to form the convex portion 2111, that is, it is formed by stamping or stretching, which is not limited herein.

[0134] It can be understood that by providing the first through hole 2114 to sequentially penetrate the support portion 2112 and the inclined surface 2113, the opening area of the first through hole 2114 is further increased, which ensures the smooth air flow below the first diaphragm 31 and improves the high-frequency performance of the first diaphragm 31, and at the same time ensures the magnet volume of the central magnetic portion 22, thereby ensuring the magnetic field strength. Optionally, the first through hole 2114 includes a plurality of them, and the plurality of first through holes 2114 are spaced apart and arranged around the convex portion 2111.

[0135] In this embodiment, the outer contour of the first top plate 211 and the central magnetic portion 22 can be selected as circular. In order to further increase the opening area of the first through hole 2114, the first through hole 2114 can be selected as an arc-shaped hole extending along the circumference of the convex portion 2111.

[0136] In one embodiment, the side of the support portion 2112 facing the support member 24 is recessed toward the air flow channel 2115 to form a support groove, and the peripheral edge of the support member 24 is limited within the support groove. It can be understood that by recessing the peripheral edge of the first top plate 211, the side of the support portion 2112 facing the support member 24 is recessed toward the air flow channel 2115 to form a support groove, so that the support groove can be used to position and install the support member 24, improving the installation accuracy.

[0137] Optionally, the first bottom plate 212 is provided with an avoidance groove 2121 corresponding to the second magnetic gap 26, and the avoidance groove 2121 is used to provide an avoidance for the second voice coil 34. It can be understood that the avoidance groove 2121 provides an avoidance space for the second voice coil 34, thus improving the performance of the sound generating device 100.

[0138] In one embodiment, as Figure 3 、 Figure 4 shown, the edge magnetic portion 23 includes an edge magnet 231 and an edge magnetic conductive plate 232 arranged in a stacked manner, and the edge magnet 231 is connected to the magnetic yoke 21. It can be understood that the edge magnet 231 is connected to the first bottom plate 212 of the magnetic yoke 21, that is, the edge magnet 231 is clamped between the first bottom plate 212 and the edge magnetic conductive plate 232, and the inner peripheral edges of the edge magnet 231 and the edge magnetic conductive plate 232 are both spaced from the annular magnet 28 to form the second magnetic gap 26. Optionally, the edge magnet 231 and the edge magnetic conductive plate 232 of the edge magnetic portion 23 can be a ring structure, which is not limited herein.

[0139] In order to further improve the connection stability, in this embodiment, the edge magnetic conductive plate 232 and the housing 1 are of an integrally formed structure. It can be understood that the housing 1 can be made of a metal material or a plastic material. When the housing 1 is made of a metal material, the housing 1 and the edge magnetic conductive plate 232 are integrally processed, so that both the processing steps can be simplified and the heat dissipation effect can be improved. When the housing 1 is made of a plastic material, the housing 1 and the edge magnetic conductive plate 232 can be integrally injection molded, which is not limited herein.

[0140] Optionally, the edge magnetic conductive plate 232 and the second housing 12 of the housing 1 are of an integrally formed structure, which is not limited herein. In this embodiment, the edge magnetic conductive plate 232 is injection molded on the housing 1, and the first leakage hole 111 is formed by removing material from the edge magnetic conductive plate 232 and / or the corresponding housing 1 area. It can be understood that by removing material on the edge magnetic conductive plate 232 or the housing 1 or both on the edge magnetic conductive plate 232 and the housing 1 to form the first leakage hole 111, the first leakage hole 111 does not additionally occupy the radial dimension of the sound generating device 100, or the size of the first leakage hole 111 can be increased under the limited size of the sound generating device 100 to balance the internal pressure.

[0141] In one embodiment, the support member 24 includes a second top plate 242, second side plates 243 provided at the periphery of the second top plate 242, and a second bottom plate 244 extending outward from one end of the second side plates 243 away from the second top plate 242. The second bottom plate 244 is connected to the side of the first top plate 211 facing away from the central magnetic portion 22, so that the second top plate 242, the second side plates 243, and the first top plate 211 enclose an air flow chamber 241. The second top plate 242 is provided with a second through hole 2421, and the inner periphery of the second diaphragm 32 is connected to the side of the second top plate 242 facing away from the air flow chamber 241, so that the third through hole 324 communicates with the second through hole 2421.

[0142] In this embodiment, as Figure 3 , Figure 4 , Figure 8 , Figure 9 shown, the support member 24 may be an integrally formed structure. The second side plates 243 are provided at the periphery of the second top plate 242 and are arranged at an angle with the second top plate 242, that is, the second side plates 243 and the second top plate 242 enclose a concave cavity. The second bottom plate 244 is connected to one end of the second side plates 243 away from the second top plate 242 and extends in a direction away from the concave cavity, that is, the second bottom plate 244 is arranged at an angle with the second side plates 243. In this way, the support member 24 is connected to the first top plate 211 of the magnetic yoke 21 by using the second bottom plate 244, thereby increasing the contact area and improving the connection stability. Moreover, the second side plates 243 of the support member 24 support the second top plate 242 away from the first top plate 211 of the magnetic yoke 21, so that the second top plate 242, the second side plates 243, and the first top plate 211 of the magnetic yoke 21 enclose an air flow chamber 241, and the inner periphery of the second diaphragm 32 is fixed by using the second top plate 242 of the support member 24.

[0143] Optionally, the support member 24 is a metal part, and the second bottom plate 244 is adhesively connected or welded to the magnetic yoke 21, that is, the second bottom plate 244 is adhesively connected or welded to the first top plate 211 of the magnetic yoke 21. Of course, in other embodiments, the support member 24 is an injection molded part, and the support member 24 and the magnetic yoke 21 are integrally injection molded, that is, the support member 24 and the first top plate 211 of the magnetic yoke 21 are integrally injection molded, which is not limited herein.

[0144] It can be understood that the second top plate 242 of the support member 24 is provided with a second through hole 2421, so that the air flow cavity 241 communicates with the outside through the second through hole 2421 and the third through hole 324 of the second diaphragm 32. In this embodiment, the third through hole 324 of the second diaphragm 32 can be one or more. When the third through hole 324 is one, that is, the second diaphragm 32 is an annular diaphragm, at this time, the inner peripheral edge of the second diaphragm 32 forms the third through hole 324, that is, the second through hole 2421 of the second top plate 242 is located within the projection range of the third through hole 324 on the second top plate 242. When the third through hole 324 is multiple, at this time, the inner side of the second diaphragm 32 is flat and is attached to the second top plate 242. The inner side of the second diaphragm 32 is provided with multiple third through holes 324, and at least part of the multiple third through holes 324 communicates with the second through hole 2421 correspondingly, which is not limited herein.

[0145] Optionally, the second through hole 2421 is one, and the second through hole 2421 communicates with the third through hole 324 correspondingly; or, the second through hole 2421 includes multiple ones, and the multiple second through holes 2421 are arranged at intervals.

[0146] It should be noted that when the second top plate 242 is provided with multiple second through holes 2421 and the inner side of the second diaphragm 32 is provided with multiple third through holes 324, optionally, the multiple second through holes 2421 are arranged in one-to-one correspondence with the multiple third through holes 324, which is not limited herein.

[0147] In an embodiment, the area of the second top plate 242 is defined as S3, and the opening area of the second through hole 2421 is defined as S4, and S4 = (10% - 80%)S3.

[0148] In this embodiment, by controlling the opening area of the second through hole 2421 on the second top plate 242, it is beneficial to the radiation of the sound wave of the first diaphragm 31 to the outside, and it can also ensure the structural strength of the support member 24 and the connection area between the inner edge of the second diaphragm 32 and the second top plate 242, thereby improving the stability. Optionally, the opening area S4 of the second through hole 2421 accounts for 10% - 80% of the area S3 of the second top plate 242. Specifically, it can be 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, etc., which is not limited herein.

[0149] It can be understood that if the area of the second through hole 2421 is too small, it is not conducive to the radiation of the sound wave of the first diaphragm 31 to the outside; if the area of the second through hole 2421 is too large, the bonding area between the second diaphragm 32 and the second top plate 242 is too small, which is not conducive to improving the connection reliability between the two.

[0150] It should be noted that when there is one second through hole 2421, the opening area S4 of the second through hole 2421 is the opening area of one second through hole 2421. When there are multiple second through holes 2421, the opening area S4 of the second through holes 2421 is the sum of the opening areas of the multiple second through holes 2421.

[0151] In one embodiment, the second diaphragm 32 is annular, an inner edge of the second diaphragm 32 forms a third through hole 324, and the sound generating device 100 further includes a second air-permeable member connected to the inner edge of the second diaphragm 32 and covering the third through hole 324.

[0152] In this embodiment, as Figure 1 、 Figure 3 、 Figure 4 shown, the second diaphragm 32 can be an annular diaphragm. At this time, the inner edge of the second diaphragm 32 forms a third through hole 324, that is, the inner edge of the second diaphragm 32 forms one third through hole 324. It can be understood that by providing the second air-permeable member, the second air-permeable member is connected to the inner edge of the second diaphragm 32 and covers the third through hole 324, so as to prevent external dust or impurities from entering the inside of the sound generating device 100, thereby avoiding affecting the acoustic performance of the sound generating device 100.

[0153] In one embodiment, the first diaphragm 31 includes a surround portion 311 and a dome 312. The surround portion 311 is disposed around the dome 312. An outer edge of the surround portion 311 is connected to the housing 1, and the first voice coil 33 is connected to the dome 312.

[0154] In this embodiment, as Figure 3 、 Figure 4 、 Figure 6 shown, the surround portion 311 and the dome 312 of the first diaphragm 31 can be an integrally formed structure or a split structure, which is not limited herein. It can be understood that the surround portion 311 of the first diaphragm 31 is a convex structure protruding upward or a concave structure recessed downward, which is not limited herein. Optionally, the surround portion 311 protrudes in a direction away from the magnetic circuit system 2.

[0155] It can be understood that the outer edge of the surround portion 311 is connected to the housing 1, and the first voice coil 33 is connected to the dome 312. In this way, when the first voice coil 33 vibrates, it drives the first diaphragm 31 to vibrate, so that the sound wave of the first diaphragm 31 radiates outward along the first magnetic gap 25, the air flow channel 2115, the first through hole 2114, the air flow cavity 241, the second through hole 2421, and the third through hole 324, and at the same time radiates outward along the through hole 27, the air flow cavity 241, the second through hole 2421, and the third through hole 324, which is not limited herein.

[0156] In one embodiment, the outer contour of the dome 312 is circular, and the through-hole 27 is a circular hole. Define the diameter of the dome 312 as D1 and the diameter of the through-hole 27 as D2, where D2 ≥ 0.3D1. It can be understood that the diameter sizes of the dome 312 and the through-hole 27 directly affect the transmission of the sound waves of the first diaphragm 31. Through the above diameter design method, it can ensure the smooth transmission of the sound waves of the first diaphragm 31 and reduce the air flow sound.

[0157] In order to achieve the smooth transmission of the sound waves of the first diaphragm 31, in another embodiment, define the projected area of the through-hole 27 along the vibration direction of the vibration system as S5, and define the projected area of the dome 312 along the vibration direction of the vibration system as S6, where S5 ≥ 8.5% * S6. It can be understood that through the above projected area design method, it can ensure the smooth transmission of the sound waves of the first diaphragm 31 and reduce the air flow sound. In practical applications, select a suitable structural design according to specific requirements to meet the smooth transmission of the sound waves of the first diaphragm 31 and reduce the air flow sound, which is not limited here.

[0158] In one embodiment, the outer peripheral edge of the first diaphragm 31 includes at least one straight edge and at least one arc edge, and the straight edge is connected to the arc edge, so that the outer contour of the first diaphragm 31 is non-circular.

[0159] In this embodiment, the outer peripheral edge of the surround portion 311 of the first diaphragm 31 includes at least one straight edge and at least one arc edge, and the straight edge is connected to the arc edge. Optionally, the outer contour of the dome 312 is similar to the outer contour of the surround portion 311, which is not limited here.

[0160] Optionally, the end face of the housing 1 connected to the first diaphragm 31 includes at least one straight edge portion and at least one arc portion. The straight edge of the first diaphragm 31 is correspondingly connected to the straight edge portion of the housing 1, and the arc edge of the first diaphragm 31 is correspondingly connected to the arc portion of the housing 1.

[0161] It can be understood that when the first leakage hole 111 penetrates the surface of the housing 1 facing the second side, the first leakage hole 111 corresponds to the straight edge of the first diaphragm 31 and is located on the side of the straight edge portion of the housing 1 away from the straight edge of the first diaphragm 31. In this way, the straight edge portion of the housing 1 and the straight edge of the first diaphragm 31 can be used to avoid the first leakage hole 111.

[0162] In one embodiment, the outer peripheral edge of the first diaphragm 31 includes a straight edge and an arc edge, and the straight edge is connected to the arc edge. The first diaphragm 31 is symmetrically arranged along the center line of the straight edge.

[0163] In another embodiment, the outer peripheral edge of the first diaphragm 31 includes two straight edges and two arc edges. The two ends of each straight edge are respectively connected to one end of the two arc edges, and the two ends of each arc edge are respectively connected to one end of the two straight edges; wherein, the two straight edges are symmetrically arranged, and the two arc edges are symmetrically arranged.

[0164] In one embodiment, as Figure 1 , Figure 3 , Figure 4 shown, the second diaphragm 32 includes an inner folding ring 321, a vibrating part 322 and an outer folding ring 323 which are connected in sequence. The inner peripheral edge of the inner folding ring 321 is connected to the support member 24 and is provided with a third through hole 324. The outer side of the outer folding ring 323 is connected to the housing 1, and the second voice coil 34 is connected to the vibrating part 322; wherein, the second diaphragm 32 further includes a vibrating plate 325, and the vibrating plate 325 is arranged between the vibrating part 322 and the second voice coil 34.

[0165] It can be understood that by setting the second diaphragm 32 as a double folding ring structure, while facilitating the vibration of the second voice coil 34 to drive the second diaphragm 32 to vibrate, the compliance of the second diaphragm 32 is improved, and its high-frequency performance is improved. The inner side of the inner folding ring 321 of the second diaphragm 32 can be an annular structure or a flat plate structure. When the inner side of the inner folding ring 321 is an annular structure, a third through hole 324 is formed on the inner side of the inner folding ring 321; when the inner side of the inner folding ring 321 is a flat plate structure, the flat plate structure is provided with a third through hole 324, which is not limited here.

[0166] In this embodiment, the inner folding ring 321 and the outer folding ring 323 of the second diaphragm 32 are convex hull structures bulging upward or concave hull structures sunken downward, which is not limited here. It can be understood that the inner folding ring 321 of the second diaphragm 32 bulges in the direction away from the support member 24, so as to avoid interference from the support member 24 when the second diaphragm 32 vibrates. Optionally, both the inner folding ring 321 and the outer folding ring 323 of the second diaphragm 32 bulge in the direction away from the magnetic circuit system 2.

[0167] Optionally, the inner folding ring 321, the vibrating part 322 and the outer folding ring 323 of the second diaphragm 32 are integrally formed structures, so as to simplify the processing steps of the second diaphragm 32 and improve the structural strength of the second diaphragm 32.

[0168] In one embodiment, as Figure 3 , Figure 4 shown, the second diaphragm 32 further includes a vibrating plate 325, and the vibrating plate 325 is arranged between the vibrating part 322 and the second voice coil 34. It can be understood that by setting the vibrating plate 325, the structural strength of the second diaphragm 32 is enhanced, the acoustic performance of the second diaphragm 32 is improved, and the second diaphragm 32 is prevented from being torn when the second voice coil 34 vibrates.

[0169] In one embodiment, asFigures 3 to 5 As shown, the sound generating device 100 further includes a first positioning ring 41, and the first positioning ring 41 is disposed between the outer peripheral edge of the first diaphragm 31 and the housing 1. Optionally, the first positioning ring 41 can be a steel ring. By adopting the first positioning ring 41 between the outer peripheral edge of the folding ring portion 311 of the first diaphragm 31 and the housing 1, the first diaphragm 31 is convenient to pick up during the assembly process, and at the same time, the assembly accuracy is improved, and the performance of the sound generating device 100 is improved.

[0170] In one embodiment, as Figure 3 、 Figure 4 As shown, the sound generating device 100 further includes a second positioning ring 42, and the second positioning ring 42 is disposed between the outer peripheral edge of the second diaphragm 32 and the housing 1. Optionally, the second positioning ring 42 can be a steel ring. By adopting the second positioning ring 42 between the outer peripheral edge of the outer folding ring 323 of the second diaphragm 32 and the housing 1, the second diaphragm 32 is convenient to pick up during the assembly process, and at the same time, the assembly accuracy is improved, and the performance of the sound generating device 100 is improved.

[0171] In one embodiment, the sound generating device 100 further includes a front cover 6. The peripheral edge of the front cover 6 is connected to the housing 1 and is located on the side of the first diaphragm 31 facing away from the second diaphragm 32. A second cavity 61 is formed between the first diaphragm 31 and the front cover 6. The front cover 6 is provided with a fourth through hole 62 communicating the second cavity 61 and the outside; wherein, the sound wave on the side of the first diaphragm 31 facing the second side is radiated outward through the fourth through hole 62.

[0172] In this embodiment, as Figures 2 to 5 、 Figure 10 As shown, by providing the front cover 6, on the one hand, the first diaphragm 31 is protected by the front cover 6, and on the other hand, the second cavity 61 is formed between the front cover 6 and the first diaphragm 31 to ensure the amplitude of the first diaphragm 31. It can be understood that by providing the fourth through hole 62 communicating the second cavity 61 and the outside on the front cover 6, it is convenient for the sound wave on the side of the first diaphragm 31 facing the second side to be radiated outward through the fourth through hole 62. Optionally, the outer peripheral edge contour of the front cover 6 is similar to the outer peripheral edge contour of the first diaphragm 31.

[0173] Optionally, the front cover 6 is a metal part formed by processing a metal material, which is convenient to strongly support the sound generating device 100 during the assembly process of the sound generating device 100 and at the same time reduces the occupation of the overall size of the machine. In a specific application, a suitable number of fourth through holes 62 are set according to the actual situation, and it is not limited to a fixed number. Preferably, a damping member or a breathable film, etc. is provided on the fourth through hole 62, which can further adjust the air flow velocity in the second cavity 61 and adjust the acoustic resistance of the second cavity 61.

[0174] In one embodiment, as Figures 2 to 4 、 Figure 7As shown in the figure, one end of the outer shell 1 facing away from the second diaphragm 32 is further provided with a support boss 113 and a retaining wall 114 connected to the support boss 113. The front cover 6 includes a top cover portion 63, a side plate portion 64 provided at the periphery of the top cover portion 63, and an edge portion 65 extending outward from one end of the side plate portion 64 away from the top cover portion 63. The edge portion 65 is supported on the support boss 113, and the surface of the retaining wall 114 facing the second side protrudes from the surface of the edge portion 65 facing the second side. The top cover portion 63 is provided with a fourth through hole 62.

[0175] It can be understood that by providing the support boss 113 and the retaining wall 114 on the outer shell 1, the front cover 6 is supported and fixed by the support boss 113 and the retaining wall 114, and at the same time, the positioning and installation of the front cover 6 are realized. Optionally, the top cover portion 63, the side plate portion 64 and the edge portion 65 of the front cover 6 are of an integrally formed structure. The front cover 6 is connected to the housing 1 through the edge portion 65, and the top cover portion 63 is supported by the side plate portion 64, so that a second cavity 61 is formed between the first diaphragm 31 and the front cover 6.

[0176] In another embodiment, as Figure 5 , Figure 10 shown, the front cover 6 includes a top cover portion 63, a side plate portion 64 provided at the periphery of the top cover portion 63, an edge portion 65 extending outward from one end of the side plate portion 64 away from the top cover portion 63, and a bent portion 66 formed by bending and extending the edge portion 65. The bent portion 66 is connected to the outer shell 1, and the bent portion 66 and the edge portion 65 form a limiting space 67 with the outer shell 1. The periphery of the first diaphragm 31 is limited in the limiting space 67. The top cover portion 63 is provided with a fourth through hole 62.

[0177] In this embodiment, by setting the front cover 6 as an integrally formed top cover portion 63, side plate portion 64, edge portion 65 and bent portion 66, the bent portion 66 of the front cover 6 is connected to the outer shell 1, so that a limiting space 67 is formed between the bent portion 66 and the edge portion 65 and the outer shell 1. In this way, the periphery of the first diaphragm 31 can be accommodated and limited in the limiting space 67, so as to increase the effective vibration area of the first diaphragm 31 and synchronously increase the volume of the second cavity 61, thus improving the acoustic performance of the first diaphragm 31.

[0178] As Figure 11 and Figure 12 shown, the present invention also provides an electronic device 800, which includes the above-mentioned sound generating device 100. The specific structure of the sound generating device 100 refers to the foregoing embodiments. Since this electronic device adopts all the technical solutions of the foregoing embodiments, it has at least all the beneficial effects brought by the technical solutions of the foregoing embodiments, and will not be elaborated herein one by one.

[0179] In one embodiment, the electronic device 800 further includes a device housing 700. The device housing 700 is provided with a receiving cavity 710. The sound generating device 100 is disposed in the receiving cavity 710 and divides the receiving cavity 710 into a front cavity 740 and a rear cavity 750 that are isolated from each other. The first side of the sound generating device 100 communicates with the front cavity 740. Among them, the device housing 700 is provided with a sound outlet hole 720 that communicates with the front cavity 740. The sound waves of the first diaphragm 31 and the second diaphragm 32 of the sound generating device 100 facing the first side are radiated to the outside through the front cavity 740 and the sound outlet hole 720.

[0180] In this embodiment, the device housing 700 can be a metal housing or a plastic housing, which is not limited herein. The device housing 700 can be an integrally formed structure or a split structure, which is not limited herein. Optionally, the device housing 700 includes an upper shell and a lower shell, and the upper shell and the lower shell can be adhesively connected or welded together to enclose and form the receiving cavity 710.

[0181] Optionally, the outer contour of the device housing 700 can be a square structure. In specific applications, other suitable shapes such as a circle can be selected according to the actual situation, and it is not limited to a specific shape.

[0182] It can be understood that a sound outlet hole 720 communicating with the front cavity 740 is provided on the upper shell of the device housing 700, so that the sound waves on the first side of the first diaphragm 31 and the second diaphragm 32 of the sound generating device 100 are radiated to the outside through the front cavity 740 and the sound outlet hole 720.

[0183] In this embodiment, the sound waves of the first diaphragm 31 and the second diaphragm 32 of the sound generating device 100 facing the second side are radiated to the rear cavity 750. The first cavity 13 of the sound generating device 100 communicates with the rear cavity 750 through a first leakage hole 111, and the second side of the first diaphragm 31 communicates with the rear cavity 750. It can be understood that the first diaphragm 31 and the second diaphragm 32 vibrate in the same direction, and the sound waves of the first diaphragm 31 and the second diaphragm 32 facing the second side are out of phase with the sound waves facing the first side.

[0184] In one embodiment, the device housing 700 is further provided with a second leakage hole 730, and the second leakage hole 730 communicates with the rear cavity 750. Among them, the first diaphragm 31 and the second diaphragm 32 of the sound generating device 100 radiate sound waves that are out of phase with the sound waves in the front cavity 740 to the rear cavity 750, and the sound waves in the rear cavity 750 are radiated to the outside through the second leakage hole 730.

[0185] It can be understood that as Figure 11 and Figure 12As shown, a second leakage hole 730 is provided on the lower shell of the device housing 700. The second leakage hole 730 communicates with the rear cavity 750. The first diaphragm 31 and the second diaphragm 32 radiate sound waves with a phase opposite to that of the sound waves in the front cavity 740 into the rear cavity 750, and the sound waves in the rear cavity 750 are radiated to the outside through the second leakage hole 730. Optionally, a damping member for adjusting the acoustic resistance is provided on the second leakage hole 730.

[0186] In this embodiment, a second leakage hole 730 is provided on the lower shell of the device housing 700. The second leakage hole 730 communicates with the rear cavity 750 and is used to adjust the pressure in the rear cavity 750 and further adjust the air pressure in the first cavity 13. At the same time, the sound waves in the rear cavity 750 are radiated to the outside through the second leakage hole 730. The sound waves in the rear cavity 750 are opposite in phase to the sound waves in the front cavity 740, which can play the role of a sound dipole and achieve the technical effects of far-field noise cancellation and protecting user privacy.

[0187] In this embodiment, the second leakage hole 730 can be selected as a circular hole, an elliptical hole, a polygonal hole, etc., which is not limited herein. The number of the second leakage holes 730 can be one or more, which is specifically designed according to actual applications and is not limited herein.

[0188] In this embodiment, the upper shell includes a top wall and a first side wall, and the lower shell includes a bottom wall and a second side wall. The first side wall and the second side wall together form the side wall of the housing of the electronic device 800, that is, the device housing 700 includes a top wall and a bottom wall arranged opposite to each other and a side wall connecting the top wall and the bottom wall. Optionally, the sound outlet hole 720 is provided on the top wall or the connection area between the side wall and the top wall, and the second leakage hole 730 is provided on the side wall or the bottom wall or the connection area between the side wall and the bottom wall. In this way, the sound emission performance of the electronic device 800 and the technical effect of protecting privacy can be taken into account, and the most suitable design scheme can be selected according to actual needs during use, which is not limited in this application.

[0189] The above are only optional embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A sound generating device, characterized in that, The sound generating device includes: a housing; a magnetic circuit system, which is connected to the housing. The magnetic circuit system includes a central magnetic part, an edge magnetic part, a ring magnet, a magnetic yoke and a support. The magnetic yoke includes a first top plate and a first bottom plate provided at both ends of the ring magnet. The central magnetic part is provided on the first top plate and is spaced from the ring magnet to form a first magnetic gap. The edge magnetic part is provided on the first bottom plate and is spaced from the ring magnet to form a second magnetic gap. The second magnetic gap is arranged to surround the first magnetic gap. The support is provided on a side of the first top plate facing away from the central magnetic part and encloses an air flow cavity with the first top plate. The first top plate is provided with a first through hole communicating the first magnetic gap and the air flow cavity. The support is provided with a second through hole communicating the air flow cavity. The magnetic circuit system is further provided with a through hole sequentially penetrating the central magnetic part and the first top plate, and the through hole communicates with the air flow cavity; and a vibration system, which includes a first diaphragm, a second diaphragm, a first voice coil and a second voice coil. The first diaphragm and the second diaphragm are located on opposite sides of the magnetic circuit system. The outer peripheral edge of the first diaphragm is connected to the housing and is opposite to and spaced from the magnetic circuit system. The outer peripheral edge of the second diaphragm is connected to the housing. The inner peripheral edge of the second diaphragm is connected to the support. And a third through hole communicating the second through hole is provided at the inner peripheral edge of the second diaphragm. One end of the first voice coil is connected to the first diaphragm, and the other end of the first voice coil is suspended in the first magnetic gap. One end of the second voice coil is connected to the second diaphragm, and the other end of the second voice coil is suspended in the second magnetic gap; wherein, the sound generating device has a first side of the second diaphragm facing away from the first diaphragm and a second side of the first diaphragm facing away from the second diaphragm. The sound wave of the first diaphragm facing the first side is radiated outward through the through hole, the air flow cavity, the second through hole and the third through hole, and at the same time is radiated outward through the first magnetic gap, the first through hole, the air flow cavity, the second through hole and the third through hole, and jointly radiates to the first side with the sound wave of the second diaphragm facing the first side.

2. The sound generating device according to claim 1, wherein The first top plate and the first bottom plate are connected to both ends of the ring magnet along the vibration direction of the vibration system. The first top plate includes a convex part and a support part connected to each other. The convex part protrudes from the first top plate toward the central magnetic part, so that the support part surrounds the convex part; wherein, the support part is provided with the first through hole. The central magnetic part is provided on the convex part and is spaced from the support part to enclose an air flow channel. The air flow channel communicates the first magnetic gap and the first through hole. The support is connected to a side of the support part facing away from the air flow channel. The through hole sequentially penetrates the central magnetic part and the convex part.

3. The sound generating device according to claim 2, wherein, An inclined surface is formed at the connection between the convex part and the support part. The first through hole sequentially penetrates the support part and the inclined surface; And / or, the first through holes include a plurality of them, and the plurality of first through holes are arranged at intervals and surround the convex portion; And / or, the first through hole is an arc-shaped hole extending along the periphery of the convex portion; And / or, on the side of the support portion facing the support member, a support groove is recessed towards the air flow channel, and the periphery of the support member is limited within the support groove; And / or, the first bottom plate is provided with an avoidance groove corresponding to the second magnetic gap, and the avoidance groove is used to provide avoidance for the second voice coil; And / or, define the area of the first top plate as S1, define the opening area of the through hole as S2, and S2=(10% - 80%)S1; And / or, the central magnetic portion includes a centrally stacked magnet and a central magnetic conductive plate, the central magnet is connected to the convex portion, and the through hole sequentially penetrates the central magnetic conductive plate, the central magnet and the convex portion.

4. The sound generating device according to claim 1, wherein The support member includes a second top plate, a second side plate provided on the periphery of the second top plate, and a second bottom plate formed by extending outward from one end of the second side plate away from the second top plate. The second bottom plate is connected to the side of the first top plate facing away from the central magnetic portion, so that the second top plate, the second side plate and the first top plate enclose to form the air flow cavity. The second top plate is provided with the second through hole, and the inner periphery of the second diaphragm is connected to the side of the second top plate facing away from the air flow cavity, so that the third through hole communicates with the second through hole; Wherein, there is one second through hole, and the second through hole corresponds to and communicates with the third through hole; or, the second through holes include a plurality of them, and the plurality of second through holes are arranged at intervals; and / or, define the area of the second top plate as S3, define the opening area of the second through hole as S4, and S4=(10% - 80%)S3; and / or, the support member is a metal member, and the second bottom plate is adhesively connected or welded to the first top plate; or, the support member is an injection molded part, and the support member and the first top plate are integrally injection molded.

5. The sound generating device according to claim 2, wherein A first cavity is formed among the second diaphragm, the housing, the annular magnet, the magnetic yoke and the support member, and the housing is provided with a first leakage hole communicating the first cavity with the outside; Wherein, the sound wave of the second diaphragm facing the second side is radiated outward through the first leakage hole, and jointly radiates to the second side with the sound wave of the first diaphragm facing the second side.

6. The sound generating device according to claim 5, wherein, The housing includes a first housing body and a second housing body connected to each other. One end of the first housing body away from the second housing body is connected to the outer periphery of the first diaphragm, and the side of the second housing body facing away from the first housing body is connected to the outer periphery of the second diaphragm. The outer periphery of the first bottom plate is connected to the first housing body; Wherein, the first housing body is provided with the first leakage hole, the first leakage hole penetrates the surface of the first housing body facing the second side, and the first leakage hole is located outside the first diaphragm; or, the side wall of the first housing body or the second housing body is provided with the first leakage hole; or, the connection part between the first housing body and the second housing body forms the first leakage hole.

7. The sound generating device according to claim 6, characterized in that, The inner wall of the first housing is convexly provided with a support platform. The outer peripheral edge of the first bottom plate and the outer peripheral edge of the first diaphragm are respectively arranged on both sides of the support platform. A first leakage hole is formed between the inner wall of the first housing and the support platform. And / or, the edge magnetic part includes a laminated edge magnet and an edge magnetic conductive plate. The edge magnet is connected to the first bottom plate, and the edge magnetic conductive plate is connected to the second housing. A leakage channel communicating with the first leakage hole is formed between the edge magnetic conductive plate and the second housing.

8. The sound generating device according to claim 1, characterized in that, The first diaphragm includes a surround portion and a dome. The surround portion surrounds the dome. The outer edge of the surround portion is connected to the housing, and the first voice coil is connected to the dome. And / or, the second diaphragm includes an inner surround, a vibrating portion, and an outer surround that are connected in sequence. The inner peripheral edge of the inner surround is connected to the support member and is provided with the third through hole. The outer side of the outer surround is connected to the housing, and the second voice coil is connected to the vibrating portion. Wherein, the second diaphragm further includes a vibrating plate, and the vibrating plate is arranged between the vibrating portion and the second voice coil.

9. The sound generating device according to claim 1, wherein The sound generating device further includes a front cover. The periphery of the front cover is connected to the housing and is located on the side of the first diaphragm facing away from the second diaphragm. A second cavity is formed between the first diaphragm and the front cover. The front cover is provided with a fourth through hole communicating the second cavity and the outside. Wherein, the sound wave of the first diaphragm facing the second side is radiated outward through the fourth through hole.

10. The sound generating device according to claim 9, wherein One end of the housing facing away from the second diaphragm is further provided with a support boss and a retaining wall connected to the support boss. The front cover includes a top cover portion, a side plate portion provided on the periphery of the top cover portion, and an edge portion extending outward from one end of the side plate portion away from the top cover portion. The edge portion is supported on the support boss. The surface of the retaining wall facing the second side protrudes from the surface of the edge portion facing the second side. The top cover portion is provided with the fourth through hole. Or, the front cover includes a top cover portion, a side plate portion provided on the periphery of the top cover portion, an edge portion extending outward from one end of the side plate portion away from the top cover portion, and a bent portion formed by bending and extending the edge portion. The bent portion is connected to the housing, and a limiting space is formed between the bent portion and the edge portion and the housing. The periphery of the first diaphragm is limited within the limiting space. The top cover portion is provided with the fourth through hole.

11. The sound generating device according to any one of claims 1 to 10, characterized in that, The first diaphragm and the second diaphragm vibrate in the same direction. The first diaphragm and the second diaphragm radiate a first sound wave to the external environment facing the first side, and the first diaphragm and the second diaphragm radiate a second sound wave to the external environment facing the second side. The first sound wave and the second sound wave are out of phase; or, the sound generating device is applied to an electronic device and is used to divide the space of the electronic device into an acoustically isolated front cavity and a rear cavity. The first side communicates with the front cavity, and the second side communicates with the rear cavity. The first diaphragm and the second diaphragm vibrate in the same direction, radiate a first sound wave to the front cavity, and radiate a second sound wave to the rear cavity. The first sound wave and the second sound wave are out of phase. And / or, the second diaphragm is annular, an inner edge of the second diaphragm forms the third through hole, and the sound generating device further includes a second air-permeable member, which is connected to the inner edge of the second diaphragm and covers the third through hole; And / or, the sound generating device further includes a first positioning ring, which is disposed between an outer peripheral edge of the first diaphragm and the housing; And / or, the sound generating device further includes a second positioning ring, which is disposed between an outer peripheral edge of the second diaphragm and the housing.

12. An electronic device, characterized in that, The electronic device includes: A device housing, which is provided with a receiving cavity; and The sound generating device according to any one of claims 1 to 11, the sound generating device is disposed in the receiving cavity and divides the receiving cavity into a front cavity and a rear cavity that are isolated from each other, and a first side of the sound generating device communicates with the front cavity; Wherein, the device housing is provided with a sound outlet hole communicating with the front cavity, and sound waves on a first side of the first diaphragm and the second diaphragm of the sound generating device are radiated to the outside through the front cavity and the sound outlet hole.

13. The electronic device according to claim 12, wherein The device housing is further provided with a second leakage hole, and the second leakage hole communicates with the rear cavity; Wherein, the first diaphragm and the second diaphragm of the sound generating device radiate sound waves having a phase opposite to that of the sound waves in the front cavity to the rear cavity, and the sound waves in the rear cavity are radiated to the outside through the second leakage hole.

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