Sound generating device and terminal device

Abstract

The present invention discloses a sound generating device and a terminal device. The sound generating device includes a chassis, a magnetic circuit system, and a vibration system. The chassis is provided with a cavity. The magnetic circuit system includes a U-shaped iron and an inner magnetic circuit portion disposed in the cavity. The U-shaped iron has a receiving groove, and the inner magnetic circuit portion is disposed in the receiving groove and spaced from the side wall of the receiving groove to form a magnetic gap. A notch groove is provided on one side of the inner magnetic circuit portion facing the magnetic gap. The vibration system includes a diaphragm and a voice coil connected to the diaphragm. The diaphragm is connected to the chassis and faces the magnetic circuit system. One end of the voice coil away from the diaphragm is suspended in the magnetic gap. Wherein, the length of the notch groove along the axis direction of the magnetic gap is defined as a, and the length of the notch groove along the direction perpendicular to the axis direction of the magnetic gap is defined as b. Wherein, 1.8 ≤ a / b ≤ 2.2. The present invention aims to provide a sound generating device that increases the magnetic permeability of the washer. The sound generating device not only effectively reduces the weight, ensures good BL value and linear range, but also meets the design requirements of miniaturization and light weight.

Description

Technical Field

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

[0002] A speaker, also known as a loudspeaker, is an electroacoustic transducer that converts electrical energy into sound energy through a certain physical effect. When different electrical energies are transmitted to the voice coil of the speaker, the voice coil generates an energy that interacts with the magnetic field of the magnet. This interaction causes the diaphragm to vibrate. Since the electrical energy changes at any time, the voice coil of the speaker moves forward or backward, so the diaphragm of the speaker will move accordingly. This action changes the density of the air to generate sound.

[0003] In related technologies, the top plates of speakers are mostly cylindrical or circular ring-shaped, and are bonded to the magnet with glue to form the magnetic circuit system of the speaker together with the U-shaped iron or T-shaped iron. The top plate plays a role in guiding magnetism and forms a magnetic circuit together with the U-shaped iron or T-shaped iron and the magnet, so that the energized voice coil makes a cutting magnetic induction line movement therein, driving the diaphragm to vibrate and generate sound. However, the magnetic permeability of some regions of the disk-shaped or circular ring-shaped top plate is very low. Retaining the regions with low magnetic permeability results in an increase in the weight of the top plate, which cannot meet the design requirements of miniaturization and light weight, and there are also problems with poor BL value and linear range. Summary of the Invention

[0004] The main object of the present invention is to provide a sound generating device and a terminal device, aiming to provide a sound generating device that increases the magnetic permeability of the top plate. This sound generating device not only effectively reduces the weight, ensures good BL value and linear range, but also can meet the design requirements of miniaturization and light weight.

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

[0006] A chassis, which is provided with a cavity;

[0007] A magnetic circuit system, which includes a U-shaped iron and an inner magnetic circuit part arranged in the cavity. The U-shaped iron has a receiving groove, and the inner magnetic circuit part is arranged in the receiving groove and is spaced from the side wall of the receiving groove to form a magnetic gap. A notch groove is provided on one side of the inner magnetic circuit part facing the magnetic gap; and

[0008] A vibration system, which includes a diaphragm and a voice coil connected to the diaphragm. The diaphragm is connected to the chassis and is opposite to the magnetic circuit system, and one end of the voice coil far away from the diaphragm is suspended in the magnetic gap;

[0009] Wherein, the length of the notch groove along the axis direction of the magnetic gap is defined as a, and the length of the notch groove along the direction perpendicular to the axis direction of the magnetic gap is defined as b; wherein, 1.8 ≤ a / b ≤ 2.2.

[0010] In one embodiment, the inner magnetic circuit portion includes an inner magnet and an inner washer arranged in a stacked manner. The inner magnet is clamped between the inner washer and the bottom wall of the accommodation groove. A notch groove is provided on one side of the inner washer facing the magnetic gap, and a recessed groove is provided on the side of the inner washer facing away from the inner magnet.

[0011] In one embodiment, the inner wall of the recessed groove includes a connected convex arc surface and a concave arc surface. The side of the convex arc surface away from the concave arc surface is connected to the outer side wall of the inner washer.

[0012] In one embodiment, the distance from the connection between the convex arc surface and the outer side wall of the inner washer to the notch groove is defined as d1, and the maximum thickness of the inner washer is defined as d2;

[0013] wherein, 0.5 ≤ d1 / d2 ≤ 0.7.

[0014] In one embodiment, the vertical distance between the connection of the convex arc surface and the concave arc surface and the connection of the convex arc surface and the outer side wall of the inner washer is defined as d3; wherein, d3 / d1 < 1 / 2;

[0015] And / or, the minimum thickness of the inner washer is defined as d4, wherein, d4 > d1 / 10.

[0016] In one embodiment, the radius of the convex arc surface is defined as R1, and the radius of the concave arc surface is defined as R2; wherein, 5.5 mm ≤ R1 ≤ 6.5 mm, 3.5 ≤ R1 / R2 ≤ 4.5;

[0017] And / or, the arc length of the convex arc surface is defined as L1, and the arc length of the concave arc surface is defined as L2, wherein, 2.5 ≤ L2 / L1 ≤ 5.

[0018] In one embodiment, the speaker frame is provided with a through hole communicating with the cavity. The U-shaped iron is provided with a first through hole penetrating the bottom wall of the accommodation groove corresponding to the through hole. The inner magnet is provided with a second through hole corresponding to the first through hole. The inner washer is provided with a third through hole corresponding to the second through hole, and the third through hole penetrates the bottom wall of the recessed groove.

[0019] In one embodiment, the bottom wall of the accommodation groove protrudes towards the inside of the accommodation groove to form a support platform. The support platform and the side wall of the accommodation groove are spaced apart to enclose an avoidance groove. The avoidance groove communicates with the magnetic gap correspondingly. The inner magnet is supported on the support platform, and a groove is recessed on the side of the U-shaped iron facing away from the bottom wall of the accommodation groove corresponding to the support platform;

[0020] And / or, the notch groove extends along the periphery of the inner washer;

[0021] And / or, the notch groove is disposed adjacent to the inner magnet.

[0022] In one embodiment, the vibration system further includes a centering ring. The inner side of the centering ring is connected to the outer wall of the voice coil, and a fixing platform is provided on the inner wall of the cavity. The outer side of the centering ring is connected to the fixing platform.

[0023] The present invention also provides a terminal device, including a device housing and the above-mentioned sound generating device, and the sound generating device is disposed in the device housing.

[0024] The sound generating device of the technical solution of the present invention installs, fixes and protects the magnetic circuit system and the vibration system by providing a cavity in the chassis. By setting the magnetic circuit system as a U-shaped iron and an inner magnetic circuit part, while installing and fixing the inner magnetic circuit part by using the accommodation groove of the U-shaped iron, a magnetic gap for suspending the voice coil of the vibration system is formed at an interval between the inner magnetic circuit part and the side wall of the accommodation groove of the U-shaped iron. In this way, after the voice coil is energized, the voice coil makes a movement of cutting magnetic induction lines in the magnetic gap of the magnetic circuit system, thereby driving the diaphragm to vibrate and generate sound. By providing a notch groove on one side of the inner magnetic circuit part facing the magnetic gap, the part with low magnetic permeability of the inner magnetic circuit part is cancelled, so as to reduce the weight of the inner magnetic circuit part, and the part with high magnetic permeability of the inner magnetic circuit part is fully utilized to ensure good BL value and linear range of the sound generating device, while also meeting the design requirements of miniaturization and light weight. Description of the Drawings

[0025] 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 following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.

[0026] Figure 1 It is a schematic cross-sectional view of the sound generating device in an embodiment of the present invention;

[0027] Figure 2 It is a schematic exploded cross-sectional view of the sound generating device in an embodiment of the present invention;

[0028] Figure 3 It is a schematic cross-sectional view of the U-shaped iron in an embodiment of the present invention;

[0029] Figure 4 It is a schematic cross-sectional view of the inner washer in an embodiment of the present invention;

[0030] Figure 5 It is a schematic diagram of the simulated magnetic induction lines of the magnetic circuit system in an embodiment of the present invention;

[0031] Figure 6It is a schematic diagram of the simulated magnetic induction lines of the magnetic circuit system in the prior art.

[0032] Explanation of the reference numerals in the attached drawings:

[0033]

[0034]

[0035] The realization, functional features and advantages of the object of the present invention will be further described with reference to the embodiments and the attached drawings. Specific embodiments

[0036] 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. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of protection of the present invention.

[0037] 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 and movement conditions between components in a specific posture (as shown in the attached drawings). If the specific posture changes, the directional indications will also change accordingly.

[0038] At the same time, the meaning of "and / or" or "and / or" appearing 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 A and B are satisfied simultaneously.

[0039] In addition, the descriptions such as "first", "second", etc. in the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating 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 the various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement it. When the combination of technical solutions appears to be 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.

[0040] A horn, also known as a loudspeaker, is an electroacoustic transducer that converts electrical energy into sound energy through a certain physical effect. When different electronic energies are transmitted to the voice coil of the horn, the voice coil generates an energy that interacts with the magnetic field of the magnet. This interaction causes the diaphragm to vibrate. Since the electronic energy changes at any time, the voice coil of the horn will move forward or backward, so the diaphragm of the horn will move accordingly. This action causes changes in the density of the air to produce sound.

[0041] In related technologies, the washers of speakers are mostly cylindrical or circular ring-shaped, and are adhered to the magnets by glue, and together with the U-shaped iron or T-shaped iron form the magnetic circuit system of the speaker. The washer plays a role in guiding magnetism, and together with the U-shaped iron or T-shaped iron and the magnet forms a magnetic circuit, enabling the energized voice coil to cut the magnetic induction lines therein, driving the diaphragm to vibrate and generate sound. However, the magnetic permeability of some areas of the disc-shaped or circular ring-shaped washer is very low. Retaining the areas with low magnetic permeability results in an increase in the weight of the washer, which cannot meet the design requirements of miniaturization and light weight, and there are also problems with poor BL value and linear range.

[0042] Based on the above concepts and problems, the present invention proposes a sound generating device 100. It can be understood that the sound generating device 100 is applied to terminal devices, and the terminal devices can be speakers, car speakers, etc., which are not limited herein.

[0043] Please refer to Figures 1 to 4 As shown, in an embodiment of the present invention, the sound generating device 100 includes a chassis 1, a magnetic circuit system 2 and a vibration system 3. The chassis 1 is provided with a cavity 11. The magnetic circuit system 2 includes a U-shaped iron 21 and an inner magnetic circuit part 22 disposed in the cavity 11. The U-shaped iron 21 has a receiving groove 211. The inner magnetic circuit part 22 is disposed in the receiving groove 211 and is spaced from the side wall of the receiving groove 211 to form a magnetic gap 23. A notch groove 2221 is provided on one side of the inner magnetic circuit part 22 facing the magnetic gap 23. The vibration system 3 includes a diaphragm 31 and a voice coil 32 connected to the diaphragm 31. The diaphragm 31 is connected to the chassis 1 and is opposite to the magnetic circuit system 2. One end of the voice coil 32 away from the diaphragm 31 is suspended in the magnetic gap 23; wherein, the length of the notch groove 2221 along the axis direction of the magnetic gap 23 is defined as a, and the length of the notch groove 2221 along the direction perpendicular to the axis direction of the magnetic gap 23 is defined as b; wherein, 1.8 ≤ a / b ≤ 2.2.

[0044] In this embodiment, the chassis 1 is used to install, fix, support and protect components such as the vibration system 3 and the magnetic circuit system 2, that is, the chassis 1 provides an installation basis for components such as the vibration system 3 and the magnetic circuit system 2. It can be understood that the chassis 1 can be a structure such as an installation shell, a housing or a box body with a cavity 11, that is, the chassis 1 defines a receiving space, which is not limited herein.

[0045] It can be understood that the chassis 1 can be selected as a cylindrical, square or horn-shaped structure, etc. The cavity 11 of the chassis 1 can be a cavity structure with one end open, and of course it can also be a cavity structure with both ends open. In this embodiment, the chassis 1 is a columnar or basin-shaped structure with one end open. The magnetic circuit system 2 is disposed in the cavity 11 of the chassis 1. By connecting and fixing the periphery of the diaphragm 31 of the vibration system 3 to one end of the chassis 1 and covering the opening, the diaphragm 31 is opposite to the magnetic circuit system 2 to enclose a vibration space of the sound generating device 100.

[0046] In this embodiment, the magnetic circuit system 2 includes a U-shaped iron 21 and an inner magnetic circuit part 22. The U-shaped iron 21 is arranged in a U shape. At this time, the U-shaped iron 21 has a receiving groove 211 with an open end. The U-shaped iron 21 is arranged in the receiving cavity 11 of the chassis 1. The notch of the receiving groove 211 faces the diaphragm 31. The inner magnetic circuit part 22 is arranged in the receiving groove 211 and is spaced from the side wall of the receiving groove 211 to enclose a magnetic gap 23. The voice coil 32 of the vibration system 3 is located in the vibration space of the sound generating device 100, so that one end of the voice coil 32 is connected to the diaphragm 31, and the other end of the voice coil 32 is suspended in the magnetic gap 23. In this way, when the voice coil 32 is energized, the voice coil 32 introduces electrical energy into the magnetic gap 23 of the magnetic circuit system 2. Under the action of the magnetic field of the magnetic circuit system 2, the voice coil 32 is driven to cut the magnetic induction line, so as to convert electrical energy into mechanical energy. When the voice coil 32 moves, it drives the diaphragm 32 to vibrate, so that the diaphragm 32 vibrates to generate sound, so as to convert mechanical energy into sound energy and realize electro-acoustic conversion.

[0047] It can be understood that when the chassis 1 is a metal part, the magnetic circuit system 2 and the chassis 1 are fixed by bonding or welding, so as to improve the heat dissipation effect of the sound generating device 100. In another embodiment, when the chassis 1 is injection molded of plastic, the U-shaped iron 21 of the magnetic circuit system 2 can also be used as an insert and injection molded into the chassis 1, or the magnetic circuit system 2 and the chassis 1 are fixed by bonding, and then other parts are fixed by bonding, which is not limited here.

[0048] In this embodiment, as Figures 1 to 4 shown, by providing a notch groove 2221 on the side of the inner magnetic circuit part 22 facing the magnetic gap 23, defining the length of the notch groove 2221 along the axis direction of the magnetic gap 23 as a, and defining the length of the notch groove 2221 along the direction perpendicular to the axis direction of the magnetic gap 23 as b, so that the ratio range of the length a of the notch groove 2221 along the axis direction of the magnetic gap 23 to the length b of the notch groove 2221 along the direction perpendicular to the axis direction of the magnetic gap 23 is within the range of 1.8 to 2.2. Thus, by providing the notch groove 2221 on the inner magnetic circuit part 22, the part with low magnetic permeability on the inner magnetic circuit part 22 is cancelled, so as to reduce the weight of the inner magnetic circuit part 22. In this way, the part with high magnetic permeability of the inner magnetic circuit part 22 can be fully utilized to ensure good BL value and linear range of the sound generating device 100, while meeting the design requirements of miniaturization and light weight.

[0049] It can be understood that the axis direction of the magnetic gap 23 is the moving direction of the voice coil 32, and the direction perpendicular to the axis of the magnetic gap 23 is the direction from the inner magnetic circuit part 22 to the side wall of the receiving groove 211 of the U-shaped iron 21. Optionally, the ratio of the length a of the notch groove 2221 along the axis direction of the magnetic gap 23 to the length b of the notch groove 2221 along the direction perpendicular to the axis direction of the magnetic gap 23 is 1.8, 1.9, 2, 2.1, 2.2, etc., which is not limited here.

[0050] The sound generating device 100 of the present invention forms a cavity 11 within the speaker frame 1, thereby using the cavity 11 of the speaker frame 1 to install, fix, and protect the magnetic circuit system 2 and the vibration system 3. By setting the magnetic circuit system 2 as the U-shaped iron 21 and the inner magnetic circuit part 22, while installing and fixing the inner magnetic circuit part 22 using the accommodation groove 211 of the U-shaped iron 21, a magnetic gap 23 is formed with a space between the inner magnetic circuit part 22 and the side wall of the accommodation groove 211 of the U-shaped iron 21 for suspending the voice coil 32 of the vibration system 3. In this way, after the voice coil 32 is energized, the voice coil moves in the magnetic gap 23 of the magnetic circuit system 2 to cut the magnetic induction lines, thereby driving the diaphragm 31 to vibrate and generate sound. By providing a notch groove 2221 on one side of the inner magnetic circuit part 22 facing the magnetic gap 23, the part with low magnetic permeability of the inner magnetic circuit part 22 is cancelled, so as to reduce the weight of the inner magnetic circuit part 22, and make full use of the part with high magnetic permeability of the inner magnetic circuit part 22. While ensuring good BL value and linear range of the sound generating device 100, it can also meet the design requirements of miniaturization and light weight.

[0051] In one embodiment, the inner magnetic circuit part 22 includes an inner magnet 221 and an inner washer 222 arranged in a stacked manner. The inner magnet 221 is clamped between the inner washer 222 and the bottom wall of the accommodation groove 211. A notch groove 2221 is provided on one side of the inner washer 222 facing the magnetic gap 23, and a recessed groove 2222 is provided on the side of the inner washer 222 facing away from the inner magnet 221.

[0052] In this embodiment, as Figure 1 、 Figure 2 and Figure 4 shown, the inner magnetic circuit part 22 includes an inner magnet 221 and an inner washer 222. The inner magnet 221 can be selected as a magnet, and the inner washer 222 can be selected as a magnetic conductive plate structure. The shape profile of the inner magnet 221 is the same as or consistent with the shape profile of the inner washer 222. Optionally, the inner magnet 221 and the inner washer 222 can be circular, oval, square, or racetrack-shaped, etc., which are not limited herein.

[0053] It can be understood that the shape profiles of the inner magnet 221 and the inner washer 222 of the inner magnetic circuit part 22 are generally similar to the shape profile of the accommodation groove 211 of the U-shaped iron 21. Optionally, the U-shaped iron 21 is a cylindrical structure with one end open. In this embodiment, by providing a notch groove 2221 on one side of the inner washer 222 facing the magnetic gap 23 and a recessed groove 2222 on the side of the inner washer 222 facing away from the inner magnet 221, the inner washer 222 forms a stepped structure, thereby further cooperating with the notch groove 2221 and the recessed groove 2222 to cancel the part with low magnetic permeability on the inner washer 222, so as to reduce the weight of the inner washer 222 and achieve the weight reduction purpose, while ensuring the magnetic permeability and magnetic field strength of the inner washer 222 under the action of the inner magnet 221.

[0054] In this embodiment, the notch groove 2221 can be structures such as a notch or a groove. The recessed groove 2222 can be optionally a groove structure or a through groove structure, etc., which is not limited herein. The recessed groove 2222 is recessed from the side of the inner washer 222 facing away from the inner magnet 221 towards the inner magnet 221. Optionally, the recessed groove 2222 is located in the middle of the inner washer 222.

[0055] To further increase the magnetic flux density at the magnetic gap 23, the inner wall of the recessed groove 2222 is arranged in an arc shape, so that the airflow generated by the vibration of the diaphragm 31 flows more smoothly. In this embodiment, as Figure 5 and Figure 6 shown, the notch groove 2221 and the recessed groove 2222 of the inner washer 222 of the present invention cooperate to remove the part with low magnetic permeability on the inner washer 222, which can increase the magnetic flux density of the inner washer 222. In this way, on the premise of ensuring the magnetic flux, the weight of the inner washer 222 can be effectively reduced, and the use efficiency of the inner washer 222 can be improved.

[0056] It can be understood that in order to ensure that when the voice coil 32 of the vibration system 3 makes a cutting magnetic induction line movement in the magnetic gap 23, a constant number of voice coils can maintain the maximum displacement in the magnetic gap 23, the voice coil 32 adopts a long voice coil and cooperates with the stepped inner washer 222, so that the inner washer 222 is stepped adjacent to the magnetic gap 23, which can increase the magnetic flux density at the magnetic gap 23, ensure that the sound generating device 100 has a high sensitivity, and increase the linear range of the sound generating device 100 while ensuring the BL value.

[0057] Optionally, the notch groove 2221 extends along the periphery of the inner washer 222. In this way, the notch groove 2221 extends along the circumferential direction of the magnetic gap 23 to form an annular groove structure on the outer side wall of the inner washer 222. To further ensure the magnetic flux density of the inner washer 222 at the magnetic gap 23, the notch groove 2221 is arranged adjacent to the inner magnet 221.

[0058] In this embodiment, the notch groove 2221 penetrates the bottom surface of the inner washer 222 facing the inner magnet 221, so that the outer side wall of the inner washer 222 facing the magnetic gap 23 is arranged in a stepped manner.

[0059] In one embodiment, the chassis 1 is provided with a through hole 12 communicating with the accommodating cavity 11. The U-shaped iron 21 is provided with a first through hole 212 penetrating the bottom wall of the accommodating groove 211 corresponding to the through hole 12. The inner magnet 221 is provided with a second through hole 2211 corresponding to the first through hole 212. The inner washer 222 is provided with a third through hole 2223 corresponding to the second through hole 2211, and the third through hole 2223 penetrates the bottom wall of the recessed groove 2222.

[0060] In this embodiment, as Figures 1 to 4As shown, by providing a through hole 12 on the chassis 1 and providing a through hole structure corresponding to the through hole 12 on the inner magnetic circuit portion 22, when the voice coil 32 drives the diaphragm 31 to vibrate, the air pressure balance within the vibration space is ensured. It can be understood that the through hole 12 is opened on the bottom wall of the cavity 11 of the chassis 1 and penetrates the bottom wall of the cavity 11. The inner magnetic circuit portion 22 is fixed to the bottom wall of the cavity 11 of the chassis 1, and the U-shaped iron 21, the inner magnet 221, and the inner washer 222 of the inner magnetic circuit portion 22 are successively provided with a first through hole 212, a second through hole 2211, and a third through hole 2223 corresponding to the through hole 12.

[0061] It can be understood that the first through hole 212, the second through hole 2211, and the third through hole 2223 are coaxially arranged. The shape profiles of the first through hole 212, the second through hole 2211, and the third through hole 2223 are the same. The first through hole 212, the second through hole 2211, and the third through hole 2223 can be selected as round holes, oval holes, triangular holes, square holes, etc., and are not limited herein.

[0062] In this embodiment, the third through hole 2223 penetrates the bottom wall of the recessed groove 2222, so that the weight of the inner washer 222 can be further reduced to achieve the purpose of weight reduction. Optionally, the third through hole 2223 is provided in the middle or intermediate position of the recessed groove 2222, so that the magnetic flux density within the magnetic gap 23 can be ensured to be uniform, and phenomena such as polarization or swinging of the voice coil 32 can be avoided, so as to improve the sound output effect of the sound generating device 100.

[0063] In one embodiment, the inner wall of the recessed groove 2222 includes a connected convex arc surface 2224 and a concave arc surface 2225. The side of the convex arc surface 2224 away from the concave arc surface 2225 is connected to the outer side wall of the inner washer 222, and the side of the concave arc surface 2225 away from the convex arc surface 2224 is connected to the hole wall of the third through hole 2223.

[0064] In this embodiment, as Figure 2 and Figure 4 shown, by setting the inner wall of the recessed groove 2222 as the connected convex arc surface 2224 and concave arc surface 2225, the convex arc surface 2224 is located at the edge of the concave arc surface 2225 and is connected to the outer side wall of the inner washer 222, so as to ensure that the upper end portion of the inner washer 222 is set with a smooth transition, so as to uniformize the magnetic induction lines and further increase the magnetic flux density at the magnetic gap 23. Optionally, the connection between the convex arc surface 2224 and the concave arc surface 2225 is set with a smooth transition, that is, the inner wall of the recessed groove 2222 is in a smooth arc surface structure, so that the air flow generated by the vibration of the diaphragm 31 flows more smoothly.

[0065] In one embodiment, it is defined that the distance from the connection between the convex arc surface 2224 and the outer side wall of the inner washer 222 to the notch groove 2221 is d1, and the maximum thickness of the inner washer 222 is defined as d2; wherein, 0.5 ≤ d1 / d2 ≤ 0.7.

[0066] In this embodiment, as Figure 4 shown, by ensuring the length of the Nevars 222 adjacent to the outer wall of the magnetic gap 23, the magnetic flux density of the Nevars 222 at the magnetic gap 23 is ensured. It can be understood that the length of the Nevars 222 adjacent to the outer wall of the magnetic gap 23 is the distance d1 from the connection of the convex arc surface 2224 and the outer wall of the Nevars 222 to the notch groove 2221. The maximum thickness d2 of the Nevars 222 is the vertical distance from the connection of the convex arc surface 2224 and the outer wall of the Nevars 222 to the bottom surface of the inner magnet 221 facing the Nevars 222.

[0067] Optionally, the ratio range of the distance d1 from the connection of the convex arc surface 2224 and the outer wall of the Nevars 222 to the notch groove 2221 to the maximum thickness d2 of the Nevars 222 is 0.5 - 0.7. Optionally, the ratio of d1 / d2 is 0.5, 0.6, 0.7, etc., which is not limited here.

[0068] In one embodiment, the vertical distance between the connection of the convex arc surface 2224 and the concave arc surface 2225 and the connection of the convex arc surface 2224 and the outer wall of the Nevars 222 is defined as d3; wherein, d3 / d1 < 1 / 2.

[0069] In this embodiment, as Figure 4 shown, by defining the vertical distance from the connection of the convex arc surface 2224 and the concave arc surface 2225 to the side of the Nevars 222 facing away from the inner magnet 221, the magnetic flux density of the Nevars 222 adjacent to the magnetic gap 23 is further ensured. It can be understood that the vertical distance d3 between the connection of the convex arc surface 2224 and the concave arc surface 2225 and the connection of the convex arc surface 2224 and the outer wall of the Nevars 222 is the vertical distance from the connection of the convex arc surface 2224 and the concave arc surface 2225 to the side of the Nevars 222 facing away from the inner magnet 221.

[0070] It can be understood that the ratio range of the vertical distance d3 between the connection of the convex arc surface 2224 and the concave arc surface 2225 and the connection of the convex arc surface 2224 and the outer wall of the Nevars 222 to the distance d1 from the connection of the convex arc surface 2224 and the outer wall of the Nevars 222 to the notch groove 2221 is < 1 / 2, so that the Nevars 222 adjacent to the magnetic gap 23 is in a stepped shape, which can increase the magnetic flux density at the magnetic gap 23, ensure that the sound generating device 100 has a high sensitivity, and increase the linear range of the sound generating device 100 while ensuring the BL value.

[0071] In one embodiment, the minimum thickness of the Nevars 222 is defined as d4, wherein, d4 > d1 / 10. It can be understood that the thickness of the Nevars 222 is the thickness along the axial direction of the magnetic gap 23, that is, the thickness of the voice coil 32 along the moving direction of the magnetic gap 23.

[0072] Optionally, in the direction of the inner washer 222 from adjacent to the magnetic gap 23 to the third through-hole 2223, the thickness of the inner washer 222 gradually decreases. By defining that the minimum thickness d4 of the inner washer 222 is greater than 1 / 10 of the distance d1 from the connection of the convex arc surface 2224 and the outer side wall of the inner washer 222 to the notch groove 2221 (i.e., the length of the outer side wall of the inner washer 222 facing the magnetic gap 23), the magnetic flux density of the inner washer 222 is ensured.

[0073] In one embodiment, the radius of the convex arc surface 2224 is defined as R1, and the radius of the concave arc surface 2225 is defined as R2; wherein, 5.5 mm ≤ R1 ≤ 6.5 mm, 3.5 ≤ R1 / R2 ≤ 4.5.

[0074] In this embodiment, as Figure 4 shown, both the convex arc surface 2224 and the concave arc surface 2225 are arc-shaped structures. Based on the plane passing through the connection of the convex arc surface 2224 and the concave arc surface 2225 and perpendicular to the axial direction of the magnetic gap 23, the centers of the convex arc surface 2224 and the concave arc surface 2225 are located on opposite sides of this plane.

[0075] Optionally, the radius R1 of the convex arc surface 2224 is 5.5 mm to 6.5 mm. In this embodiment, the radius R1 of the convex arc surface 2224 is 5.5 mm, 5.8 mm, 6 mm, 6.3 mm, 6.5 mm, etc., which are not limited herein.

[0076] Optionally, the ratio range of the radius R1 of the convex arc surface 2224 to the radius R2 of the concave arc surface 2225 is 3.5 to 4.5. In this embodiment, the ratio of the radius R1 of the convex arc surface 2224 to the radius R2 of the concave arc surface 2225 is 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, etc., which are not limited herein.

[0077] In this embodiment, the arc length of the convex arc surface 2224 is defined as L1, and the arc length of the concave arc surface 2225 is defined as L2, wherein, 2.5 ≤ L2 / L1 ≤ 5. Optionally, the ratio of the arc length L2 of the concave arc surface 2225 to the arc length L1 of the convex arc surface 2224 is 2.5, 3, 3.5, 4, 4.5, 5, etc., which are not limited herein.

[0078] In this embodiment, as Figure 4 shown, the connection between the concave arc surface 2225 and the hole wall of the third through-hole 2223 is provided with a rounded corner. It can be understood that the radius of the rounded corner is defined as R3, 1.5 mm ≤ R3 ≤ 2.5 mm, so as to ensure that the airflow generated by the vibration of the diaphragm 31 flows more smoothly.

[0079] In one embodiment, a support platform 213 is formed by the bottom wall of the accommodation groove 211 protruding towards the inside of the accommodation groove 211. The support platform 213 is spaced from the side wall of the accommodation groove 211 to enclose an avoidance groove 214. The avoidance groove 214 corresponds to and communicates with the magnetic gap 23. The inner magnet 221 is supported on the support platform 213. On the side of the U-shaped iron 21 facing away from the bottom wall of the accommodation groove 211, a groove 215 is formed corresponding to the support platform 213. The first through hole 212 penetrates through the support platform 213 and communicates with the groove 215.

[0080] In this embodiment, as Figures 1 to 3 shown, by providing the support platform 213 on the bottom wall of the accommodation groove 211 of the U-shaped iron 21, the support platform 213 is spaced from the side wall of the accommodation groove 211 to enclose the avoidance groove 214, and the avoidance groove 214 corresponds to and communicates with the magnetic gap 23. Thus, while using the support platform 213 to support and fix the inner magnetic circuit part 22, the avoidance groove 214 is used to avoid the movement of the voice coil 32 in the magnetic gap 23, so as to ensure the amplitude of the sound generating device 100.

[0081] It can be understood that the support platform 213 may be a convex structure protruding from the bottom wall of the accommodation groove 211. Of course, the support platform 213 may also be formed by the side of the U-shaped iron 21 facing away from the bottom wall of the accommodation groove 211 protruding towards the inside of the accommodation groove 211, which is not limited herein. Optionally, on the side of the U-shaped iron 21 facing away from the bottom wall of the accommodation groove 211, a groove 215 is formed corresponding to the support platform 213. The first through hole 212 penetrates through the support platform 213 and communicates with the groove 215.

[0082] In one embodiment, as Figure 1 and Figure 2 shown, the vibration system 3 further includes a centering ring 33. The inner side of the centering ring 33 is connected to the outer wall of the voice coil 32, and a fixing platform 13 is provided on the inner wall of the accommodation cavity 11. The outer side of the centering ring 33 is connected to the fixing platform 13. It can be understood that by providing the centering ring 33, the centering ring 33 is effectively used to avoid the polarization or left-right swing of the voice coil 32 during vibration, etc., so as to improve the vibration and sound generation effect of the diaphragm 31.

[0083] It can be understood that the fixing platform 13 may be a convex platform structure convexly provided on the inner wall of the accommodation cavity 11, or may be a stepped structure formed by the inner wall of the accommodation cavity 11, which is not limited herein.

[0084] The present invention also proposes a terminal device, which includes a device housing and the above-mentioned sound generating device 100. The sound generating device 100 is provided in the device housing. For the specific structure of the sound generating device 100, reference may be made to the foregoing embodiments. Since this terminal device adopts all the technical solutions of the foregoing all embodiments, it at least has all the beneficial effects brought by the technical solutions of the foregoing embodiments, which will not be elaborated herein one by one.

[0085] The above are only alternative 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 chassis, the chassis is provided with a cavity; a magnetic circuit system, the magnetic circuit system includes a U-shaped iron and an inner magnetic circuit part disposed in the cavity, the U-shaped iron has a receiving groove, the inner magnetic circuit part includes an inner magnet and an inner washer stacked, the inner magnet is clamped between the inner washer and the bottom wall of the receiving groove, and is spaced from the side wall of the receiving groove to form a magnetic gap, a notch groove is provided on one side of the inner washer facing the magnetic gap, a concave groove is provided on the side of the inner washer facing away from the inner magnet, the inner wall surface of the concave groove is arranged in an arc shape, and both the notch groove and the concave groove are parts with low magnetic permeability of the inner washer; and a vibration system, the vibration system includes a diaphragm and a voice coil connected to the diaphragm, the diaphragm is connected to the chassis and is opposite to the magnetic circuit system, and one end of the voice coil away from the diaphragm is suspended in the magnetic gap; wherein, the length of the notch groove along the axis direction of the magnetic gap is defined as a, and the length of the notch groove along the direction perpendicular to the axis direction of the magnetic gap is defined as b; wherein, 1.8 ≤ a / b ≤ 2.

2.

2. The sound generating device according to claim 1, characterized in that The inner wall of the concave groove includes a convex arc surface and a concave arc surface connected to each other, and the side of the convex arc surface away from the concave arc surface is connected to the outer side wall of the inner washer.

3. The sound generating device according to claim 2, wherein, Define the distance from the connection between the convex arc surface and the outer side wall of the inner washer to the notch groove as d1, and define the maximum thickness of the inner washer as d2; wherein, 0.5 ≤ d1 / d2 ≤ 0.

7.

4. The sound generating device according to claim 3, wherein Define the vertical distance between the connection of the convex arc surface and the concave arc surface and the connection of the convex arc surface and the outer side wall of the inner washer as d3; wherein, d3 / d1 < 1 / 2; and / or, define the minimum thickness of the inner washer as d4, wherein, d4 > d1 / 10.

5. The sound generating device according to claim 2, characterized in that, Define the radius of the convex arc surface as R1, and define the radius of the concave arc surface as R2; wherein, 5.5 mm ≤ R1 ≤ 6.5 mm, 3.5 ≤ R1 / R2 ≤ 4.5; and / or, define the arc length of the convex arc surface as L1, and define the arc length of the concave arc surface as L2, wherein, 2.5 ≤ L2 / L1 ≤ 5.

6. The sound generating device according to claim 1, wherein The chassis is provided with a through hole communicating with the cavity, the U-shaped iron is provided with a first through hole penetrating the bottom wall of the receiving groove corresponding to the through hole, the inner magnet is provided with a second through hole corresponding to the first through hole, the inner washer is provided with a third through hole corresponding to the second through hole, and the third through hole penetrates the bottom wall of the concave groove.

7. The sound generating device according to claim 1, characterized in that, The bottom wall of the receiving groove protrudes towards the inside of the receiving groove to form a support platform, the support platform is spaced from the side wall of the receiving groove to enclose an avoidance groove, the avoidance groove is correspondingly communicated with the magnetic gap, the inner magnet is supported on the support platform, and a groove is recessed on the side of the U-shaped iron facing away from the bottom wall of the receiving groove corresponding to the support platform; and / or, the notch groove extends along the periphery of the inner washer; and / or, the notch groove is arranged adjacent to the inner magnet; 8. The sound generating device according to any one of claims 1 to 7, characterized in that, The vibration system further includes a centering ring, the inner side of the centering ring is connected to the outer wall of the voice coil, and a fixing platform is provided on the inner wall of the cavity, and the outer side of the centering ring is connected to the fixing platform.

9. A terminal device, characterized in that, Comprising a device housing and a sound generating device as described in any one of claims 1 to 8, the sound generating device being provided in the device housing.

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