Diaphragm of sound-generating device and preparation method thereof, and sound-generating device

Abstract

The present application discloses a diaphragm of a sound-generating device, a preparation method thereof, and a sound-generating device, wherein the diaphragm comprises a foamed rubber layer and a woven fabric layer, at least one side of the woven fabric layer is coated with a foamed rubber layer, the foamed rubber layer comprises a base rubber and foamed microspheres, the foamed microspheres are heated and foamed to form pores in the foamed rubber layer, wherein the particle size of the foamed microspheres is 15 μm to 45 μm, the foamed microspheres account for 3% to 10% of the total amount of the base rubber, the initial foaming temperature of the foamed microspheres is 120° C. to 200° C., the maximum foaming temperature of the foamed microspheres is 150° C. to 270° C., and the damping of the diaphragm is greater than 0.06. The present application composites the foamed rubber layer with hollow glass microspheres added thereto with the woven fabric layer, so that the diaphragm has suitable rigidity, reduces the mass of the diaphragm, and improves the damping performance of the diaphragm.

Description

Technical Field

[0001] The present application relates to the field of electroacoustic technology, and more specifically, to a diaphragm of a sound-generating device and a method for preparing the same, as well as a sound-generating device using the diaphragm. Background Art

[0002] At present, the polyurethane foam plastic used in the diaphragm of polyurethane foam plastic on the market has poor durability. When the speaker is working, the diaphragm is prone to loosening, deformation and rupture, and even bubble collapse. Although the rubber material diaphragm has good damping, compliance and fatigue resistance. However, the mass of the rubber material diaphragm is large, which will increase the mass of the vibration system, resulting in a decrease in the sound sensitivity of the speaker, and the cost of the rubber material diaphragm is high, thereby increasing the production cost of the diaphragm.

[0003] Therefore, a new technical solution is needed to solve the above problems. Summary of the invention

[0004] One object of the present application is to provide a diaphragm for a sound-generating device.

[0005] Another object of the present application is to provide a method for preparing the above-mentioned diaphragm.

[0006] Another object of the present application is to provide a sound-generating device composed of the above-mentioned diaphragm.

[0007] According to the diaphragm of the sound-emitting device of the first aspect embodiment of the present application, the diaphragm includes a foamed rubber layer and a woven fabric layer, at least one side of the woven fabric layer is coated with the foamed rubber layer, the foamed rubber layer includes a base rubber and foamed microspheres, the foamed microspheres are foamed when heated to form pores in the foamed rubber layer, wherein the particle size of the foamed microspheres is 15μm to 45μm, the foamed microspheres account for 3% to 10% of the total amount of the base rubber, the initial foaming temperature of the foamed microspheres is 120℃ to 200℃, the maximum foaming temperature of the foamed microspheres is 150℃ to 270℃, and the damping of the diaphragm is greater than 0.06.

[0008] According to some embodiments of the present application, the pore diameter of the foam cells is 20 μm to 100 μm.

[0009] According to some embodiments of the present application, the density of the diaphragm is 0.4 g / cm 3 ~1.1g / cm 3 .

[0010] According to the method for preparing a diaphragm for a sound-emitting device according to the second aspect of the present application, the steps are as follows: adding foamed microspheres to basic rubber latex to obtain modified rubber latex, coating the modified rubber latex on at least one side of a woven fabric layer, and obtaining an initial composite membrane material after drying; hot-pressing the initial composite membrane material to obtain a composite membrane; and cutting the composite membrane to obtain a diaphragm material.

[0011] According to some embodiments of the present application, the initial composite film material is placed on a molding machine for hot pressing molding, and the molding temperature is 220°C to 270°C.

[0012] According to some embodiments of the present application, when the initial composite film material is subjected to hot-pressing molding, the preparation method further comprises: placing the initial composite film material in a molding machine for holding pressure, and the holding pressure time is 6s to 15s.

[0013] According to some embodiments of the present application, the material of the woven fabric layer is plain woven fabric, and the plain woven fabric is any one of plain woven cotton fabric, plain woven PET fabric or plain woven natural silk fabric.

[0014] According to some embodiments of the present application, the plain woven fabric includes a plurality of wire bundles, and there are gaps between adjacent wire bundles, and the size of the gaps is 10 μm to 305 μm.

[0015] According to some embodiments of the present application, the gap is filled with the modified rubber latex.

[0016] According to some embodiments of the present application, each of the wiring harnesses includes a plurality of wires, the number of the wires is 10 to 45, and the wire diameters of the wires are 5 μm to 26 μm.

[0017] According to some embodiments of the present application, before applying the modified rubber latex to the woven fabric layer, the preparation method further includes: immersing the plain woven fabric in a thermosetting resin solution for thermosetting resin treatment to obtain the woven fabric layer, wherein the thermosetting resin comprises a thermosetting phenolic resin and a thermosetting epoxy resin.

[0018] According to some embodiments of the present application, the coating method is dip coating, blade coating, roller coating or spray coating.

[0019] According to some embodiments of the present application, the base rubber latex is one or more of natural rubber latex, styrene-butadiene rubber latex, butadiene rubber latex, isoprene rubber latex, chloroprene rubber latex, butyl rubber latex, nitrile rubber latex, chlorinated nitrile rubber latex, ethylene-propylene rubber latex, silicone rubber latex, fluororubber latex, polyurethane rubber latex, acrylate rubber latex, chlorosulfonated polyethylene rubber latex, epichlorohydrin rubber latex, polysulfide rubber latex and ethylene-vinyl acetate rubber latex.

[0020] According to some embodiments of the present application, the surface density of the woven fabric layer is 9 g / m 2 ~147g / m 2 .

[0021] According to some embodiments of the present application, the surface density of the composite film is 20 g / m 2 ~200g / m 2 .

[0022] According to some embodiments of the present application, the thickness of the composite film is 0.05 mm to 0.38 mm.

[0023] According to some embodiments of the present application, the modulus of the composite film is 300 MPa to 1000 MPa.

[0024] According to the third aspect of the embodiment of the present application, the sound-emitting device includes a vibration system and a magnetic circuit system coordinated with the vibration system, the vibration system includes a diaphragm and a voice coil coupled to one side of the diaphragm, the magnetic circuit system drives the voice coil to vibrate to drive the diaphragm to produce sound, and the diaphragm is the diaphragm described in the above-mentioned embodiment of the present application.

[0025] According to the fourth aspect of the present application, the sound-emitting device includes a shell and a magnetic circuit system and a vibration system arranged in the shell, the vibration system includes a voice coil, a first diaphragm and a second diaphragm, the top of the voice coil is connected to the first diaphragm, the magnetic circuit system drives the voice coil to vibrate to drive the first diaphragm to make sound, the two ends of the second diaphragm are respectively connected to the shell and the bottom of the voice coil, and the second diaphragm is the diaphragm described in the above-mentioned embodiment of the present application.

[0026] According to the diaphragm of the sound-generating device of the embodiment of the present application, a foamed rubber layer is formed by adding foamed microspheres to the base rubber, and the foamed rubber layer is coated on at least one side of the fabric layer, which can not only reduce the weight of the diaphragm, but also effectively improve the sensitivity and damping performance of the diaphragm. The sound-generating device using the diaphragm material of the present application can reduce its distortion at low frequencies, has high acoustic stability, and is low in cost.

[0027] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments of the present application with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the application and, together with the description, serve to explain the principles of the application.

[0029] Figure 1The test curves (SPL curves) of the loudness of the speaker with the diaphragm according to the embodiment of the present application and the speaker with the conventional rubber diaphragm at different frequencies;

[0030] Figure 2 The harmonic distortion test curve (THD curve) of the speaker with the diaphragm according to the embodiment of the present application and the speaker with the cloth-impregnated rubber diaphragm;

[0031] Figure 3 A schematic structural diagram of a plain woven fabric according to a method for preparing a diaphragm of a sound-generating device according to an embodiment of the present application;

[0032] Figure 4 A cross-sectional view of a composite film coated with a foam rubber layer on one side according to a method for preparing a diaphragm of a sound-generating device according to an embodiment of the present application;

[0033] Figure 5 A cross-sectional view of a composite film coated with foam rubber layers on both sides according to a method for preparing a diaphragm of a sound-generating device according to an embodiment of the present application;

[0034] Figure 6 is a schematic diagram of the overall structure of a sound-generating device according to an embodiment of the present application;

[0035] Figure 7 is a schematic diagram of a partial structure of a sound-generating device according to an embodiment of the present application;

[0036] Figure 8 is a cross-sectional view of a sound-generating device according to an embodiment of the present application;

[0037] Fig. 9 It is an exploded diagram of a sound-generating device according to an embodiment of the present application.

[0038] Reference numerals

[0039] Sound generating device 100;

[0040] Housing 10; voice coil 11; first diaphragm 12; second diaphragm 13; magnetic circuit system 14;

[0041] Diaphragm 15 ; folding ring portion 151 ; dome portion 152 . DETAILED DESCRIPTION

[0042] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0043] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present application, its application, or uses.

[0044] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0045] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0046] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0047] The diaphragm of the sound-generating device according to the embodiment of the present application is described in detail below with reference to the accompanying drawings.

[0048] According to the diaphragm of the sound-emitting device of the embodiment of the present application, the diaphragm includes a foamed rubber layer and a woven fabric layer, at least one side of the woven fabric layer is coated with the foamed rubber layer, the foamed rubber layer includes a base rubber and foamed microspheres, the foamed microspheres are foamed when heated to form pores in the foamed rubber layer, wherein the particle size of the foamed microspheres is 15μm to 45μm, the foamed microspheres account for 3% to 10% of the total amount of the base rubber, the initial foaming temperature of the foamed microspheres is 120℃ to 200℃, the maximum foaming temperature of the foamed microspheres is 150℃ to 270℃, and the damping of the diaphragm is greater than 0.06.

[0049] According to the embodiment of the present application, the diaphragm of the sound-emitting device includes a foam rubber layer and a woven fabric layer, wherein the woven fabric layer is a double-sided structure, and the foam rubber layer can be arranged on one side of the woven fabric layer, or the foam rubber layer can be arranged on both sides of the woven fabric layer.

[0050] Furthermore, the foamed rubber layer can be prepared by adding foamed microspheres to the base rubber. That is, after the foamed microspheres are added to the base rubber, the base rubber is heated, and the foamed microspheres are heated and foamed to form pores in the foamed rubber layer.

[0051] Wherein, the particle size of the foamed microsphere is 15μm to 45μm. For example, the particle size of the foamed microsphere can be 15μm, 20μm, 25μm, 30μm, 35μm, 40μm or 45μm. After foaming with foamed microspheres of this range of particle size, the obtained pores can obtain sufficient strength, thereby reducing the weight of the foamed rubber layer. In addition, the foamed microspheres account for 3% to 10% of the total amount of the base rubber. For example, the percentage of the foamed microspheres to the total amount of the base rubber can be 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%.

[0052] When the foamed microspheres account for 3% to 10% of the total base rubber, the foamed rubber layer can reduce its weight by 20% to 60%. The weight-reduced foamed rubber layer has appropriate damping, suppresses diaphragm polarization, has good sound quality and low distortion, and has superior mechanical properties, meeting acoustic performance and reliability requirements, and reducing the production cost of the diaphragm.

[0053] Specifically, Table 1 shows the test results of the surface density, loss factor and elongation at break of the foamed rubber layer of the diaphragm with different contents of foamed microspheres.

[0054] Table 1

[0055] Mass fraction of foamed microspheres (%) 0 3 6 10 15 <![CDATA[Diaphragm areal density (g / m 2 )]]> 120 100 50 40 45 Diaphragm modulus (Mpa) 800 680 400 350 450 Diaphragm loss factor 0.02 0.09 0.15 0.2 0.08

[0056] As shown in Table 1, with the increase of the amount of foamed microspheres added, the diaphragm surface density decreases significantly. However, when the content of foamed microspheres is too high, the expansion of the foamed microspheres will squeeze each other, resulting in insufficient foaming and a decrease in the foaming ratio. At this time, the diaphragm surface density will increase. The diaphragm modulus shows a trend of first decreasing and then increasing with the increase of the amount of foamed microspheres added. With the increase of the content of foamed microspheres, the diaphragm density decreases, the hardness is correspondingly smaller, and the modulus decreases. When the content of foamed microspheres is large, the expansion of the foamed microspheres is squeezed by each other, resulting in a low foaming rate, which increases the hardness of the diaphragm and the modulus increases accordingly. As the foaming rate increases, the diaphragm damping increases due to the synergistic effect of the pore structure and the viscoelasticity of the rubber material. When the content of foamed microspheres is large, the foaming ratio decreases and the hardness increases, and its rubber content will also decrease, resulting in a decrease in the damping of the diaphragm.

[0057] Figure 1 : This is a test curve (SPL curve) of the loudness at different frequencies of a speaker diaphragm according to an embodiment of the present application and a conventional rubber diaphragm. Among them, the solid line b is the test curve of the speaker diaphragm provided by the embodiment of the present application, and the dotted line a is the test curve of the conventional rubber diaphragm. It can be seen from the SPL curve that the mid-frequency sensitivity of the speaker using the diaphragm of the embodiment of the present application is significantly improved compared with the conventional rubber diaphragm.

[0058] Figure 2 : It is a harmonic distortion test curve (THD curve) of a speaker diaphragm and a cloth-impregnated rubber diaphragm according to an embodiment of the present application. Among them, the solid line b is the test curve of the speaker diaphragm provided by the embodiment of the present application, and the dotted line a is the test curve of the cloth-impregnated rubber diaphragm. It can be seen from the THD curve that the distortion of the speaker using the diaphragm of the embodiment of the present application is lower than that of the speaker using the conventional cloth-impregnated rubber diaphragm. In other words, the speaker using the speaker diaphragm of the embodiment of the present application has higher loudness and comfort.

[0059] Foaming microsphere can be expanded microsphere, and the foaming process of expanded microsphere needs shell softening, and balance is carried out between external pressure and expanded microsphere internal gas pressure.This process is affected by many factors, for example, the polymer composition of thermoplastic expanded microsphere shell, the type of thermoplastic expanded microsphere internal gas, the chemicals that shell contacts, external pressure, free expansion, expansion in substrate, substrate type and heating temperature and heating rate.Wherein, the basic rubber latex of the application is equivalent to substrate, and basic rubber latex can form basic rubber, and after foaming microsphere and basic rubber latex are mixed, foaming microsphere can be dispersed in substrate.

[0060] Furthermore, the foamed microspheres require a suitable expansion temperature range. If the expansion temperature of the foamed microspheres is too low, the foamed microspheres will be too small, and the pore size of the foamed cells formed in the substrate will be too small, which will not achieve the effect of reducing the density of the substrate. If the expansion temperature of the foamed microspheres is too high, it will cause excessive foaming, forming cracks on the substrate and reducing the mechanical strength of the foamed rubber layer.

[0061] According to the embodiment of the present application, the initial foaming temperature of the foamed microspheres is selected to be 120°C to 200°C, which can ensure that the foamed microspheres can be stably foamed in the rubber without excessive foaming or under-foaming. Furthermore, the maximum foaming temperature of the foamed microspheres is controlled within the range of 150°C to 270°C, which can ensure that the foamed microspheres are uniformly foamed in the rubber and the size of the pores formed on the substrate is stable. By adopting the above-mentioned foaming temperature, not only can the foamed microspheres be fully heated and decomposed to release gas, but the foamed product can also maintain stability in a high temperature environment, thereby obtaining a high-quality foamed rubber layer.

[0062] Therefore, according to the diaphragm of the sound-emitting device of the present application, a foamed rubber layer is formed by adding foamed microspheres to the base rubber, and the foamed rubber layer is coated on at least one side of the woven layer. This can not only reduce the weight of the diaphragm, but also effectively improve the sensitivity and damping performance of the diaphragm. The sound-emitting device using the diaphragm material of the present application can reduce its distortion at low frequencies, has high acoustic stability and low production costs.

[0063] According to one embodiment of the present application, the pore diameter of the foam cells is 20 μm to 100 μm.

[0064] The diaphragm is the weakest component in the sound-generating device. During repeated vibrations, it is necessary to ensure long-term normal use, so as to extend the life of the sound-generating device. The size of the pore diameter can affect the sensitivity and service life of the diaphragm of the sound-generating device. Smaller pores do not significantly reduce weight, while larger pores have poor durability and are prone to loosening, deformation and rupture during speaker operation. Therefore, the elastic properties and rigidity properties of the diaphragm with a pore diameter range of 20μm to 100μm can meet the production requirements of the sound-generating device. Optionally, the pore diameter can be 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm or 100μm.

[0065] According to some embodiments of the present application, the density of the diaphragm is 0.4 g / cm 3 ~1.1g / cm 3 It is understandable that, since foaming microspheres are added to the base rubber to form a foaming rubber layer, and the foaming rubber layer is coated on at least one side of the fabric layer, the weight of the diaphragm can be reduced by 30% to 50%, greatly improving the sound sensitivity of the diaphragm. Optionally, the density of the diaphragm can be 0.4g / cm 3 , 0.5g / cm 3 , 0.6g / cm 3 , 0.7g / cm 3 , 0.8g / cm 3 , 0.9g / cm 3 , 1g / cm 3 or 1.1 g / cm 3 .

[0066] According to the method for preparing a diaphragm for a sound-emitting device according to the second aspect of the embodiment of the present application, the steps are as follows: adding foamed microspheres to basic rubber latex to obtain modified rubber latex, coating the modified rubber latex on at least one side of a woven fabric layer, and obtaining an initial composite membrane material after drying; hot-pressing the initial composite membrane material to obtain a composite membrane; and cutting the composite membrane to obtain a diaphragm material.

[0067] When preparing the diaphragm, first, foamed microspheres can be added to the base rubber latex to obtain modified rubber latex, the modified rubber latex can be coated on at least one side of the fabric layer, and the fabric layer coated with the modified rubber latex can be dried to obtain an initial composite film material. Then, the initial composite film material is placed on a molding machine for hot pressing to obtain a composite film. Finally, after the composite film is cooled, the composite film is punched or laser cut according to the diaphragm design requirements to obtain a diaphragm material.

[0068] Therefore, according to the method for preparing the diaphragm of the sound-emitting device of the embodiment of the present application, a foamed rubber layer can be obtained by coating rubber latex added with foamed microspheres onto a woven fabric layer. This not only has a simple process, but also reduces the density and mass of the diaphragm, thereby making the diaphragm have higher damping. The sound-emitting device using the diaphragm of the present application has better acoustic performance.

[0069] In some specific embodiments of the present application, the initial composite film material is placed on a molding machine for hot pressing, and the molding temperature is 220° C. to 270° C. That is, by setting the molding temperature in the range of 220° C. to 270° C., the composite film material molding effect can be better, and the quality of the obtained composite film can be better.

[0070] According to one embodiment of the present application, when the initial composite film material is hot-pressed, the preparation method further includes: placing the initial composite film material in a molding machine for holding pressure, and the holding time is 6s to 15s. In other words, a suitable holding time can effectively prevent product shrinkage, and product production is relatively stable. In addition, a suitable holding method can adjust the size of the product without weld lines, dents, flash and warping deformation, thereby achieving ideal product quality control.

[0071] In some specific embodiments of the present application, the material of the woven fabric layer is plain woven fabric, and the plain woven fabric is any one of plain woven cotton fabric, plain woven PET fabric or plain woven natural silk fabric. Figure 3 The diagram shown is a schematic diagram of the structure of a plain woven fabric.

[0072] like Figure 4 As shown in FIG. 1 , the modified rubber latex is coated on one side of the fabric layer, and after molding, a composite film having a foamed rubber layer on one side of the fabric layer is obtained. Figure 5 As shown, the modified rubber latex is coated on both sides of the fabric layer, and after molding, a composite film containing foamed rubber layers on both sides of the fabric layer is obtained. Among them, the white circle in the figure is the foamed rubber layer, and the black mesh circle is the fabric layer.

[0073] According to an embodiment of the present application, the plain woven fabric includes a plurality of wire bundles, and there are gaps between adjacent wire bundles, and the size of the gaps is 10 μm to 305 μm.

[0074] If the gap between adjacent wires is too large, the composite film strength is low, and if the gap is too small, the content of the foam rubber layer will increase, and the composite film will be heavier and have lower damping. If the gap between adjacent wires is too large or too small, it will affect the tightness of the bonding between the fabric layer and the foam rubber layer, not only failing to achieve the reinforcement effect, but also reducing the mechanical properties of the composite film.

[0075] In some specific embodiments of the present application, the gap is filled with modified rubber latex. That is, when the modified rubber latex is coated on the woven fabric layer, a portion of the modified rubber latex will enter the gap and fill the gap, thereby reducing the weight of the composite film. Since the gap has a suitable size, the woven fabric layer and the foamed rubber layer can be tightly combined, thereby enhancing the mechanical properties of the composite film and improving the damping of the composite film.

[0076] According to one embodiment of the present application, each harness includes a plurality of threads, the number of threads is 10 to 45, and the thread diameter is 5 μm to 26 μm. For example, the number of threads may be 10, 20, 30 or 40, and the thread diameter may be 5 μm, 10 μm, 15 μm, 20 μm or 25 μm. In other words, the more threads there are, the larger the thread diameter is, and the denser the woven fabric layer is. By controlling the number and thread diameter of the threads, a woven fabric layer of suitable quality and strength can be obtained, so that the foam rubber layer can be better combined with the woven fabric layer, thereby forming a composite film of better quality.

[0077] In some specific embodiments of the present application, the woven fabric is immersed in a thermosetting resin solution and treated with a thermosetting resin to obtain a woven fabric layer, wherein the thermosetting resin includes a thermosetting phenolic resin and a thermosetting epoxy resin. In other words, the woven fabric layer needs to be immersed in a thermosetting resin solution and treated with a thermosetting resin before the modified rubber latex can be applied to the woven fabric layer. Specifically, the woven fabric is immersed in a thermosetting resin solution and taken out to dry.

[0078] According to an embodiment of the present application, the coating method is dip coating, scraper coating, roller coating or spray coating. That is, the coating method can be selected according to the selected material so that the foam rubber layer and the fabric layer can be well combined.

[0079] In some specific embodiments of the present application, the base rubber latex is one or more of natural rubber latex, styrene-butadiene rubber latex, butadiene rubber latex, isoprene rubber latex, chloroprene rubber latex, butyl rubber latex, nitrile rubber latex, chlorinated nitrile rubber latex, ethylene-propylene rubber latex, silicone rubber latex, fluororubber latex, polyurethane rubber latex, acrylate rubber latex, chlorosulfonated polyethylene rubber latex, chloroether rubber latex, polysulfide rubber latex and ethylene-vinyl acetate rubber latex. In other words, there can be multiple choices of base rubbers, and the effects achieved by different base rubbers are also different, so the type of base rubber can be selected according to actual conditions.

[0080] According to one embodiment of the present application, the surface density of the woven fabric layer is 9 g / m 2 ~147g / m 2 Preferably, the surface density of the woven fabric layer can be 20 g / m 2 ~90g / m 2For example, the surface density of the fabric layer can be 10 g / m 2 , 20g / m 2 , 30g / m 2 , 40g / m 2 , 50g / m 2 , 60g / m 2 , 70g / m 2 , 80g / m 2 , 90g / m 2 , 100g / m 2 , 110g / m 2 , 120g / m 2 , 130g / m 2 , 140g / m 2 Or 150g / m 2 wait.

[0081] In some specific embodiments of the present application, the surface density of the composite film is 20 g / m 2 ~200g / m 2 Preferably, the surface density of the diaphragm is 30 g / m 2 ~100g / m 2 For example, the surface density of the composite film can be 20 g / m 2 , 30g / m 2 , 40g / m 2 , 60g / m 2 , 80g / m 2 , 100g / m 2 , 120g / m 2 , 140g / m 2 , 160g / m 2 , 180g / m 2 Or 200g / m 2 The modified rubber latex is formed by adding foaming microspheres to the base rubber latex. The modified rubber latex obtained by adding different amounts of foaming microspheres has different densities. The modified rubber latex is coated on the fabric layer to form a composite film. The surface density of the composite film can be controlled at 20g / m 2 ~200g / m 2 Within the range of , the surface density of the composite film within this range can make the diaphragm have appropriate strength and ensure that the diaphragm has high damping.

[0082] According to one embodiment of the present application, the thickness of the composite membrane is 0.05mm to 0.38mm. That is to say, after the composite membrane is formed by coating the foamed rubber layer onto the woven fabric layer, the thickness of the diaphragm obtained by cutting the composite membrane can be in the range of 0.05mm to 0.38mm. For example, the thickness of the diaphragm can be 0.05mm, 0.1mm, 0.15mm, 0.25mm, 0.35mm or 0.38mm. The thickness of the modified rubber latex coating is different from the thickness of the woven fabric layer, and the thickness of the obtained composite membrane is also different. By adjusting the thickness of the composite membrane, not only the mechanical strength of the diaphragm can be guaranteed, but also the diaphragm can have a suitable loss factor, thereby ensuring the acoustic performance of the sound-emitting device.

[0083] In some specific embodiments of the present application, the modulus of the composite film is 300MPa to 1000MPa. That is to say, a modified rubber latex is formed by adding foaming microspheres to a base rubber latex, and then the amount of foaming microspheres added is adjusted, and the modified rubber latex is coated on a woven fabric layer to form a composite film. A diaphragm can be obtained by further processing the composite film. When the modulus of the composite film is controlled within the range of 300MPa to 1000MPa, the mechanical strength of the diaphragm can be guaranteed, thereby ensuring the performance of the diaphragm. Optionally, the modulus of the composite film can be 300Mpa, 400Mpa, 500Mpa, 600Mpa, 700Mpa, 800Mpa, 900Mpa or 1000Mpa. In summary, according to the method for preparing the diaphragm of the sound-emitting device of the embodiment of the present application, by using a foam rubber layer and a woven fabric layer added with foamed microspheres as raw materials to prepare the diaphragm, the diaphragm can have excellent damping performance and resilience, the vibration system can effectively suppress the polarization phenomenon during the vibration and sound generation process, the consistency of the vibration system is better, and the transient distortion of the sound-emitting device is effectively suppressed, so that the sound-emitting device made of the diaphragm of the present application has good acoustic performance.

[0084] It should be noted that the diaphragm provided in the present application can form a sound-generating device of any structure, such as the following typical sound-generating device: including a vibration system and a magnetic circuit system matched with the vibration system, the vibration system including a diaphragm and a voice coil combined with one side of the diaphragm. When the sound-generating device is working, after the voice coil is energized, under the action of the magnetic field force of the magnetic circuit system, the voice coil can vibrate up and down to drive the diaphragm to vibrate, and the diaphragm can produce sound when it vibrates.

[0085] According to the third aspect of the present application, the sound-generating device includes a vibration system and a magnetic circuit system matched with the vibration system, the vibration system includes a diaphragm and a voice coil coupled to one side of the diaphragm, the magnetic circuit system drives the voice coil to vibrate to drive the diaphragm to make a sound, and the diaphragm is the diaphragm of the above embodiment. Specifically, when the sound-generating device is working, after the voice coil is energized, under the action of the magnetic field force of the magnetic circuit system, the voice coil can vibrate up and down to drive the diaphragm to vibrate, and the diaphragm can make a sound when it vibrates.

[0086] like Figure 6 and Figure 7 As shown, the sound-generating device includes a diaphragm 15 prepared by the above-mentioned embodiment of the present application, and the diaphragm 15 can be composed of a folding ring portion 151 and a ball top portion 152, and the modified acrylic rubber membrane layer can be applied to the folding ring portion 151 of the diaphragm. Those skilled in the art can make corresponding adjustments according to actual product requirements, such as the folding ring portion 151 protrudes toward the voice coil 11 side, the ball top portion 152 is located on the lower surface of the folding ring portion 151, and a centering support is added to the vibration system.

[0087] like Figure 8 and Fig. 9 As shown, according to the fourth aspect of the present application, the sound-emitting device 100 includes a shell 10 and a magnetic circuit system 14 and a vibration system arranged in the shell 10, the vibration system includes a voice coil 11, a first diaphragm 12 and a second diaphragm 13, the top of the voice coil 11 is connected to the first diaphragm 12, the magnetic circuit system 14 drives the voice coil 11 to vibrate to drive the first diaphragm 12 to make sound, and the two ends of the second diaphragm 13 are respectively connected to the shell 10 and the bottom of the voice coil 11, and the second diaphragm 13 is the diaphragm of the above-mentioned embodiment.

[0088] That is to say, the sound-generating device 100 according to the embodiment of the present application may also include two diaphragms prepared by the above-mentioned embodiment of the present application, the first diaphragm 12 may be used for vibrating and making sounds, and the second diaphragm 13 may be used for balancing the vibration of the voice coil 11. Specifically, when the sound-generating device 100 is working, after the voice coil 11 is energized, under the action of the magnetic field force of the magnetic circuit system 14, the voice coil 11 may vibrate up and down to drive the first diaphragm 12 to vibrate, and the first diaphragm 12 may make sounds when vibrating. The second diaphragm 13 may also vibrate up and down following the voice coil 11. Since the two ends of the second diaphragm 13 are respectively connected to the housing 10 and the bottom of the voice coil 11, the second diaphragm 13 may balance the vibration of the voice coil 11, and may prevent the voice coil 11 from being polarized, thereby improving the sound-generating effect of the sound-generating device 100.

[0089] It should be noted that the first diaphragm 12 and the second diaphragm 13 may simultaneously adopt the diaphragms of the above embodiment of the present application, or one of the first diaphragm 12 and the second diaphragm 13 may adopt the diaphragm of the above embodiment of the present application, and the present application does not make any specific restrictions on this.

[0090] The diaphragm of the sound-generating device of the present application is described in detail below in conjunction with specific embodiments.

[0091] Embodiment 1

[0092] Weigh the base rubber latex and foamed microspheres by mass. The base rubber latex includes: 100 parts of nitrile rubber, 30 parts of carbon black, 4 parts of zinc oxide, 1.5 parts of stearic acid, 2.5 parts of vulcanization accelerator, and 1.8 parts of sulfur. The foamed microspheres are 5 parts, and the average particle size of the foamed microspheres is 30μm to 35μm;

[0093] After adding foamed microspheres to the base rubber latex, a modified rubber latex is obtained, and the modified rubber latex is coated on one side of the fabric layer. After the modified rubber latex is dried on the fabric layer, a foamed rubber layer is formed to obtain a composite film material. Then the composite film material can be placed on a molding machine for hot pressing. The molding temperature can be 220℃~270℃, and the holding time can be 6s~15s. After the holding is completed, the mold is opened to obtain a composite film. Finally, after waiting for the composite film to cool, the composite film is punched or laser cut according to the diaphragm design requirements to obtain a diaphragm material.

[0094] Comparative Example 1

[0095] The difference from the first embodiment is that the foamed rubber layer does not contain foamed microspheres. The other steps of preparing the diaphragm material are exactly the same as those of the first embodiment.

[0096] Test indicators: composite film surface density, loss factor, modulus

[0097] Table 2 shows the test results of the performance test of the diaphragms of Comparative Example 1 and Example 1, reflecting the effect of adding foamed microspheres on the surface density, loss factor and modulus of the diaphragm.

[0098] Test conditions:

[0099] The storage modulus and loss factor were determined by dynamic mechanical testing (DMA) according to ASTM D5026-15 standard, with a tensile fixture, a test temperature range of -50°C to 200°C, a heating rate of 3°C / min, and each group of samples was tested 3 times to take the average value.

[0100] Table 2

[0101]

[0102]

[0103] As can be seen from the table above, the diaphragm surface density of Example 1 is less than that of Comparative Example 1, and the weight is lighter. While the density of the diaphragm of Example 1 is reduced, the loss factor is greatly improved. The pore structure generated by the foamed microspheres and the viscoelasticity of the rubber material synergistically increase the damping, so that the distortion of the diaphragm made by the embodiment of the present application is reduced. The modulus of Example 1 and Comparative Example 1 is not much different, so the diaphragm F0 made by the embodiment of the present application is relatively more stable.

[0104] Therefore, compared with conventional diaphragms, the diaphragm with added foamed microspheres has lower weight and higher damping, which can reduce the vibration mass of the vibration system, ensure the acoustic stability of the sound-generating device, and make the sound-generating device have lower distortion at low frequencies.

[0105] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration, not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A diaphragm for a sound-generating device, characterized in that: The diaphragm comprises a foam rubber layer and a woven fabric layer, at least one side of the woven fabric layer is coated with the foam rubber layer, the foam rubber layer comprises a base rubber and foam microspheres, the foam microspheres are heated and foamed to form pores in the foam rubber layer; The particle size of the foamed microspheres is 15 μm to 45 μm, the foamed microspheres account for 3% to 10% of the total amount of the base rubber, the initial foaming temperature of the foamed microspheres is 120° C. to 200° C., the maximum foaming temperature of the foamed microspheres is 150° C. to 270° C., and the damping of the diaphragm is greater than 0.06; The material of the woven fabric layer is plain woven fabric, and the plain woven fabric is any one of plain woven cotton fabric, plain woven PET fabric or plain woven natural silk fabric; The plain woven fabric includes a plurality of wire bundles, and there are gaps between adjacent wire bundles. The size of the gaps is 10 μm to 305 μm.

2. The diaphragm for a sound-generating device according to claim 1, characterized in that: The pore diameter of the foam cells is 20 μm to 100 μm.

3. The diaphragm for a sound-generating device according to claim 1, characterized in that: The density of the diaphragm is 0.4 g / cm 3 ~1.1g / cm 3 .

4. A method for preparing a diaphragm for a sound-generating device according to any one of claims 1 to 3, characterized in that: Here are the steps: Adding foamed microspheres to basic rubber latex to obtain modified rubber latex, coating the modified rubber latex on at least one side of the woven fabric layer, and drying to obtain an initial composite membrane material; Performing hot pressing on the initial composite film material to obtain a composite film; The composite film is cut to obtain a diaphragm material.

5. The method for preparing a diaphragm for a sound-generating device according to claim 4, characterized in that: The initial composite film material is placed on a molding machine for hot pressing molding at a molding temperature of 220°C to 270°C.

6. The method for preparing a diaphragm for a sound-generating device according to claim 5, characterized in that: When the initial composite film material is subjected to hot-pressing molding, the preparation method further comprises: placing the initial composite film material in a molding machine for holding pressure, and the holding pressure time is 6s to 15s.

7. The method for preparing a diaphragm for a sound-generating device according to claim 4, characterized in that: The gap is filled with the modified rubber latex.

8. The method for preparing a diaphragm for a sound-generating device according to claim 4, characterized in that: Each of the wire bundles includes a plurality of wires, the number of the wires is 10 to 45, and the wire diameters of the wires are 5 μm to 26 μm.

9. The method for preparing a diaphragm for a sound-generating device according to claim 4, characterized in that: Before applying the modified rubber latex to the woven fabric layer, the preparation method further comprises: immersing the plain woven fabric in a thermosetting resin solution for thermosetting resin treatment to obtain the woven fabric layer, wherein the thermosetting resin comprises thermosetting phenolic resin and thermosetting epoxy resin.

10. The method for preparing a diaphragm for a sound-generating device according to claim 4, characterized in that: The coating method is dipping, scraping, rolling or spraying.

11. The method for preparing a diaphragm for a sound-generating device according to claim 4, characterized in that: The basic rubber latex is one or more of natural rubber latex, styrene-butadiene rubber latex, butadiene rubber latex, isoprene rubber latex, chloroprene rubber latex, butyl rubber latex, nitrile rubber latex, chlorinated nitrile rubber latex, ethylene-propylene rubber latex, silicone rubber latex, fluororubber latex, polyurethane rubber latex, acrylate rubber latex, chlorosulfonated polyethylene rubber latex, epichlorohydrin rubber latex, polysulfide rubber latex and ethylene-vinyl acetate rubber latex.

12. The method for preparing a diaphragm for a sound-generating device according to claim 4, characterized in that: The surface density of the woven fabric layer is 9 g / m 2 ~147g / m 2 .

13. The method for preparing a diaphragm for a sound-generating device according to claim 4, characterized in that: The surface density of the composite film is 20 g / m 2 ~200g / m 2 .

14. The method for preparing a diaphragm for a sound-generating device according to claim 4, characterized in that: The thickness of the composite film is 0.05 mm to 0.38 mm.

15. The method for preparing a diaphragm for a sound-generating device according to claim 4, characterized in that: The modulus of the composite film is 300MPa to 1000MPa.

16. A sound-generating device, characterized in that: It includes a vibration system and a magnetic circuit system matched with the vibration system, the vibration system includes a diaphragm and a voice coil combined with one side of the diaphragm, the magnetic circuit system drives the voice coil to vibrate to drive the diaphragm to make sound, and the diaphragm is the diaphragm described in any one of claims 1-3.

17. A sound-generating device, characterized in that: It includes a shell and a magnetic circuit system and a vibration system arranged in the shell, the vibration system includes a voice coil, a first diaphragm and a second diaphragm, the top of the voice coil is connected to the first diaphragm, the magnetic circuit system drives the voice coil to vibrate to drive the first diaphragm to make sound, the two ends of the second diaphragm are respectively connected to the shell and the bottom of the voice coil, and the second diaphragm is the diaphragm described in any one of claims 1-3.

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