Diaphragm of sound-generating device and sound-generating device

Abstract

The present application discloses a diaphragm of a sound generating device and a sound generating device. The diaphragm includes at least one modified ethylene-acrylate rubber film layer, and the modified ethylene-acrylate rubber film layer is prepared by cross-linking reaction after forming a mixed rubber by kneading inorganic hollow microspheres, additives and ethylene-acrylate polymer; wherein, the particle size of the inorganic hollow microspheres is 1 μm to 60 μm, the distribution density of the inorganic hollow microspheres in the modified ethylene-acrylate rubber film layer is 0.15 g / cm<supgt;3< / supgt> to 0.9 g / cm<supgt;3< / supgt>, and the surface contact angle between the modified ethylene-acrylate rubber film layer and water is ≥ 70°. In the present application, after kneading inorganic hollow microspheres, additives and ethylene-acrylate rubber to form a mixed rubber, a cross-linking reaction is carried out to prepare a modified ethylene-acrylate rubber film layer, and this is used as the diaphragm material, which improves the aging resistance of the diaphragm, slows down the mucosal state of the rubber diaphragm material, reduces the density of the diaphragm, and improves the mid-frequency sensitivity of the sound generating device.

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 sound-generating device using the diaphragm. Background Art

[0002] With the increasing requirements for high power, waterproof performance and high sound quality of speakers, rubber diaphragms have also been widely used in the speaker field. However, due to the high density of rubber diaphragms (≥1.2g / cm 3 ), the thickness is relatively thick, which will lead to a large mass of the diaphragm, making the rubber diaphragm have a high vibration mass in the vibration system, which will result in a low intermediate frequency Fr (frequency response) of the sound-emitting device.

[0003] In addition, when using rubber materials to manufacture diaphragms, sticking film problems are prone to occur. Sticking film will cause poor dimensional stability of rubber, difficulty in demolding, corrosion to the mold, etc. Severe sticking film will cause extremely thin diaphragms to be pulled, deformed, and broken, resulting in poor molding of diaphragm products and reduced product yield.

[0004] Therefore, a new technical solution is needed to solve the above problems. Summary of the invention

[0005] One object of the present application is to provide a diaphragm for a sound-generating device.

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

[0007] In order to achieve the above objectives, this application provides the following technical solutions.

[0008] According to the diaphragm of the sound-emitting device of the first embodiment of the present application, the diaphragm includes at least one modified ethylene-acrylate rubber film layer, and the modified ethylene-acrylate rubber film layer is prepared by mixing inorganic hollow microspheres, additives and ethylene-acrylate polymer to form a mixed rubber and then cross-linking the mixed rubber; wherein the particle size of the inorganic hollow microspheres is 1 μm to 60 μm, and the distribution density of the inorganic hollow microspheres in the modified ethylene-acrylate rubber film layer is 0.15 g / cm 3 ~0.9g / cm 3 The surface contact angle between the modified ethylene-acrylate rubber film layer and water is ≥70°.

[0009] According to some embodiments of the present application, the content of the inorganic hollow microspheres accounts for 5wt% to 48wt% of the total amount of the mixed rubber.

[0010] According to some embodiments of the present application, it is characterized in that after the modified ethylene-acrylate rubber film layer is aged in hot air at 180° C. for 168 hours, the tensile strength of the modified ethylene-acrylate rubber film layer decreases by ≤46%, and the elongation at break decreases by ≤71%.

[0011] According to some embodiments of the present application, the compressive strength of the inorganic hollow microspheres is ≥10 MPa.

[0012] According to some embodiments of the present application, the tensile strength of the modified ethylene-acrylate rubber film layer is ≥5 MPa.

[0013] According to some embodiments of the present application, the loss factor of the modified ethylene-acrylate rubber film layer at room temperature is greater than 0.12.

[0014] According to some embodiments of the present application, the density of the modified ethylene-acrylate rubber film layer is 0.5 g / cm 3 ~1.1g / cm 3 .

[0015] According to some embodiments of the present application, the glass transition temperature of the modified ethylene-acrylate rubber film layer is ≤-10°C.

[0016] According to some embodiments of the present application, the additives include a cross-linking agent, a reinforcing agent and an antioxidant, wherein the cross-linking agent is at least one of a metal oxide, a metal peroxide, an organic oxide, an organic peroxide and an amine vulcanization system; the reinforcing agent is at least one of carbon black, silica, calcium carbonate, barium sulfate, organic montmorillonite, unsaturated carboxylic acid metal salts, talcum powder, clay, mica powder, feldspar powder, sulfates, magnetic powder and diatomaceous earth; the antioxidant is at least one of antioxidant N-445, antioxidant 246, antioxidant 4010, antioxidant SP, antioxidant RD, antioxidant ODA, antioxidant OD and antioxidant WH-02.

[0017] According to some embodiments of the present application, the content of the cross-linking agent accounts for 0.5wt% to 4.6wt% of the rubber mixture, the content of the reinforcing agent accounts for 5wt% to 71wt% of the rubber mixture, and the content of the antioxidant accounts for 0.1wt% to 5.9wt% of the rubber mixture.

[0018] According to some embodiments of the present application, the diaphragm is a single-layer structure, and the diaphragm is composed of a layer of the modified ethylene-acrylate rubber film layer.

[0019] According to some embodiments of the present application, the diaphragm is a composite layer structure, and the diaphragm also includes a membrane layer made of at least one of a thermoplastic elastomer, an engineering plastic, and a thermosetting elastomer.

[0020] According to the second 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 according to the above-mentioned embodiment of the present application.

[0021] According to the third 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 according to the above-mentioned embodiment of the present application.

[0022] According to the diaphragm of the sound-generating device of the embodiment of the present application, the modified ethylene-acrylate rubber film layer prepared by cross-linking reaction after mixing inorganic hollow microspheres, additives and ethylene-acrylate rubber to form a mixed rubber is used as the diaphragm material. While ensuring that the diaphragm material has a certain mechanical strength, it can reduce the density of the diaphragm and improve the mid-frequency sensitivity of the sound-generating device. In addition, the inorganic hollow microspheres can form a dense oxide layer on the rubber surface, which not only effectively improves the aging resistance of the diaphragm material, but also improves the aging resistance of the diaphragm. In addition, through the above-mentioned settings, it is also possible to effectively slow down the mucous membrane state of the rubber diaphragm material, reduce the difficulty of demolding, and improve the product yield.

[0023] 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

[0024] 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.

[0025] Figure 1 is a test curve of vibration displacement of different parts of the diaphragm of the sound-generating device according to an embodiment of the present application at different frequencies;

[0026] Figure 2 The intermediate frequency Fr curve of the modified ethylene-acrylate rubber membrane layer with different densities of the diaphragm of the sound-generating device according to the embodiment of the present application;

[0027] Figure 3 is a schematic diagram of the overall structure of a sound-generating device according to an embodiment of the present application;

[0028] Figure 4 is a schematic diagram of a partial structure of a sound-generating device according to an embodiment of the present application;

[0029] Figure 5 is a cross-sectional view of a sound-generating device according to an embodiment of the present application;

[0030] Figure 6 It is an exploded diagram of a sound-generating device according to an embodiment of the present application.

[0031] Reference numerals

[0032] Sound generating device 100;

[0033] Housing 10; voice coil 11; first diaphragm 12; second diaphragm 13; magnetic circuit system 14;

[0034] Diaphragm 15 ; folding ring portion 151 ; dome portion 152 . DETAILED DESCRIPTION

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] According to the diaphragm of the sound-generating device of the embodiment of the present application, the diaphragm includes at least one modified ethylene-acrylate rubber membrane layer, which is prepared by mixing inorganic hollow microspheres, additives and ethylene-acrylate polymer to form a mixed rubber and then cross-linking. The particle size of the inorganic hollow microspheres is 1 μm to 60 μm, and the distribution density of the inorganic hollow microspheres in the modified ethylene-acrylate rubber membrane layer is 0.15 g / cm 3 ~0.9g / cm 3, the surface contact angle between the modified ethylene-acrylate rubber film layer and water is ≥70°.

[0042] According to the embodiment of the present application, the diaphragm of the sound-emitting device can be composed of at least one layer of modified ethylene-acrylate rubber membrane layer. Specifically, the diaphragm in the present application can be a single-layer structure or a multi-layer composite structure. When the diaphragm is a single-layer structure, that is, the diaphragm is made of a layer of modified ethylene-acrylate rubber membrane layer of the present application. When the diaphragm is a multi-layer composite structure, the diaphragm includes at least one layer of modified ethylene-acrylate rubber membrane layer, and the diaphragm is composed of a modified ethylene-acrylate rubber membrane layer and a membrane layer of other materials. Optionally, when the diaphragm contains multiple layers of modified ethylene-acrylate rubber membrane layers, two adjacent layers of modified ethylene-acrylate rubber membrane layers can be spaced apart, that is, a membrane layer of other materials can also be set between two adjacent layers of modified ethylene-acrylate rubber membrane layers. Of course, two adjacent layers of modified ethylene-acrylate rubber membrane layers can also be set in close contact with each other. The setting can be selected according to actual usage requirements, and the present application does not impose specific restrictions on this.

[0043] Specifically, the ethylene-acrylate polymer may be a copolymer of ethylene and acrylate, and its chemical formula may be at least one of the following chemical formulas:

[0044]

[0045] Wherein, x, y and z in formula (I) and formula (II) are natural numbers; R and R' are alkyl groups.

[0046] Among them, the modified ethylene-acrylate rubber film layer is made by adding inorganic hollow microspheres to ethylene-acrylate polymer. Specifically, by mixing inorganic hollow microspheres, additives and ethylene-acrylate polymer, a rubber mix can be formed, and the rubber mix can be vulcanized to form a modified ethylene-acrylate rubber film layer. Ethylene-acrylate polymer can form ethylene-acrylate rubber, and ethylene-acrylate rubber is equivalent to the base material of the diaphragm material. After the inorganic hollow microspheres and ethylene-acrylate polymer are mixed, the inorganic hollow microspheres can be dispersed in the base material. Since the distribution density of inorganic hollow microspheres is less than that of rubber, by adding inorganic hollow microspheres to rubber, the density of the modified ethylene-acrylate rubber film layer can be reduced to obtain a low-density diaphragm.

[0047] Under the condition that the ethylene-acrylate rubber diaphragm material with inorganic hollow microspheres added has the same hardness as the ethylene-acrylate rubber diaphragm material without inorganic hollow microspheres added in the prior art, the diaphragm of the present application has a lower diaphragm density and can reduce the vibration mass of the diaphragm system. That is, the diaphragm of the present application can improve the intermediate frequency response of the sound-generating device, so that the sound-generating device has a higher intermediate frequency sensitivity.

[0048] Inorganic hollow microspheres are hollow, thin-walled, hard, lightweight spheres with a high strength-to-density ratio. The diaphragm of the sound-generating device of the present application is added with inorganic hollow microspheres, which can effectively reduce the density and weight of the rubber, thereby reducing the overall weight of the diaphragm, reducing the vibration mass of the vibration system, and improving the sensitivity of the sound-generating device. The inorganic hollow microspheres can be hollow glass microspheres, hollow ceramic microspheres, etc. Among them, the main component of the hollow glass microspheres is borosilicate, which has high temperature resistance.

[0049] When inorganic hollow microspheres are added to AEM (ethylene-acrylate) rubber, a dense oxide layer is formed on the rubber surface, which hinders the penetration of oxygen molecules and effectively improves the aging resistance of AEM rubber. In addition, inorganic hollow microspheres have high compressive strength, which can ensure that the inorganic hollow microspheres are not squeezed and broken during the mixing process.

[0050] Further, the particle size of the inorganic hollow microspheres can be selected in the range of 1 μm to 60 μm, preferably 5 μm to 30 μm, for example, the particle size of the inorganic hollow microspheres can be 1 μm, 5 μm, 10 μm, 20 μm, 30, 40 μm, 50 μm or 60 μm. In other words, inorganic hollow microspheres of different particle sizes can be selected according to the different thicknesses of the diaphragm to ensure that the inorganic hollow microspheres are evenly dispersed in the substrate.

[0051] In addition, as the size of inorganic hollow microspheres decreases, the distribution density of inorganic hollow microspheres will increase, and the distribution density of inorganic hollow microspheres can be controlled at 0.15g / cm 3 ~0.9g / cm 3 For example, the distribution density of inorganic hollow microspheres can be 0.15 g / cm 3 , 0.2g / cm 3 , 0.35g / cm 3 , 0.5g / cm 3 , 0.6g / cm 3 , 0.7g / cm 3 , 0.8g / cm 3 or 0.9g / cm 3 To ensure that the inorganic hollow microspheres can effectively reduce the density of the diaphragm, the distribution density of the inorganic hollow microspheres is preferably 0.35 g / cm 3 ~0.8g / cm 3 .

[0052] It should be noted that the small molecule compounding agents inside the rubber will migrate to the rubber surface during the high-temperature processing and molding process. Multiple molding will cause the accumulation of more and more small molecule compounding agents on the mold. The small molecule compounding agents on the rubber surface and the small molecule compounding agents on the mold form a physical adsorption effect, thus causing sticky membranes.

[0053] Since the mucous membrane is related to the surface polar groups of the membrane layer, the degree of mucous membrane of the diaphragm can be characterized by measuring the surface contact angle. The smaller the surface contact angle, the higher the mucous membrane property of the diaphragm. Table 1 shows the effect of the diaphragm material formed by adding different contents of inorganic hollow microspheres to the AEM rubber on the surface contact angle of the diaphragm material. The inorganic hollow microspheres here are hollow glass microspheres. It should be noted that hollow glass microspheres are a type of inorganic hollow microspheres. The use of hollow glass microspheres or other inorganic hollow microspheres can also reflect the role of inorganic hollow microspheres in the material.

[0054] The influence of the content of inorganic hollow microspheres in the diaphragm material on the mucosal properties of the diaphragm is as follows:

[0055] The test method is: test according to the GGS1616 water drop angle standard, measure ten points for each sample and take the average value.

[0056] Table 1

[0057] Hollow glass microsphere addition amount (wt%) 0 5 10 40 48 Surface contact angle (°) 68 73 78 91 95

[0058] As shown in Table 1, with the increase of the content of hollow glass microspheres, the surface contact angle of the diaphragm material gradually increases. Specifically, when the addition amount of hollow glass microspheres is 0, the surface contact angle of the diaphragm material is only 68°. With the increase of the addition amount of hollow glass microspheres, the surface contact angle component of the diaphragm material increases. Since the inorganic hollow microspheres have high rigidity and can form a dense protective layer on the rubber surface, the migration of small molecule compounding agents can be effectively prevented, which greatly reduces the mucous state of the rubber diaphragm. That is, by adding inorganic hollow microspheres to the ethylene-acrylate polymer, the present application can ensure that the surface contact angle between the modified ethylene-acrylate rubber film layer and water is ≥70°, thereby effectively solving the mucous membrane problem of the diaphragm and reducing the difficulty of demolding the diaphragm.

[0059] Therefore, according to the diaphragm of the sound-generating device of the embodiment of the present application, the modified ethylene-acrylate rubber film layer prepared by cross-linking reaction after forming a mixed rubber using inorganic hollow microspheres, additives and ethylene-acrylate polymers is used as the diaphragm material. While ensuring that the diaphragm material has a certain mechanical strength, it can reduce the density of the diaphragm and improve the intermediate frequency response of the sound-generating device. In addition, the inorganic hollow microspheres can form a dense oxide layer on the rubber surface, which can effectively improve the aging resistance of the diaphragm material. In addition, through the above-mentioned settings, it is also possible to effectively slow down the mucous membrane state of the rubber diaphragm material and effectively reduce the difficulty of demolding the diaphragm.

[0060] According to one embodiment of the present application, the compressive strength of the inorganic hollow microspheres is ≥10 MPa.

[0061] In other words, the inorganic hollow microspheres have a high compressive strength, which can not only ensure that the inorganic hollow microspheres are not squeezed and crushed during the mixing process, but also add them to the ethylene-acrylate polymer to effectively improve the tensile strength of the modified ethylene-acrylate rubber film layer. When the diaphragm has a high mechanical strength, it can ensure that the diaphragm will not be over-stretched due to excessive driving force in extreme environments, further ensuring the use effect of the diaphragm.

[0062] In some specific embodiments of the present application, the content of the inorganic hollow microspheres accounts for 5wt% to 48wt% of the total amount of the mixed rubber.

[0063] That is to say, inorganic hollow microspheres accounting for 5wt% to 48wt% of the total amount of the mixed rubber can be added to the ethylene-acrylate polymer. As the amount of inorganic hollow microspheres added increases, the density of the modified ethylene-acrylate rubber film layer decreases, and the diaphragm material with the required performance can be obtained by controlling the amount of inorganic hollow microspheres added. The content of inorganic hollow microspheres can be any value between 5wt% and 48wt%, for example, the content of inorganic hollow microspheres can be 5wt%, 10wt%, 15wt%, 20wt%, 30wt%, 40wt% or 48wt%.

[0064] It should be noted that, since the density of inorganic hollow microspheres is much lower than that of rubber, the density of the rubber material will decrease significantly as the amount of inorganic hollow microspheres added increases. Specifically, when the content of inorganic hollow microspheres is low (less than 5wt%), it has little effect on the density of the diaphragm material, and the diaphragm still has a relatively high density.

[0065] When the content of inorganic hollow microspheres is too high (greater than 48wt%), due to its high mechanical strength, the maximum amplitude that can be achieved by the prepared diaphragm under the same driving force is reduced, which reduces the low frequency Fr of the sound-generating device. In addition, excessive addition of inorganic hollow microspheres will greatly reduce the density of the modified ethylene-acrylate rubber membrane layer, and the prepared diaphragm has low elongation at break and strength, which is prone to reliability problems such as collapse and film breakage.

[0066] Therefore, by using a modified ethylene-acrylate rubber film layer prepared by adding 5wt% to 48wt% of inorganic hollow microbeads to the total amount of the mixed rubber as the diaphragm material, the density and strength of the diaphragm can be achieved at the same time, effectively ensuring the excellent mid-frequency and low-frequency performance of the diaphragm.

[0067] According to one embodiment of the present application, after the modified ethylene-acrylate rubber film layer is aged in hot air at 180° C. for 168 hours, the tensile strength of the modified ethylene-acrylate rubber film layer decreases by ≤46%, and the elongation at break decreases by ≤71%.

[0068] Specifically, the chemical composition of hollow glass microspheres is borosilicate, which has high temperature resistance. When added to AEM rubber, it forms a dense oxide layer on the rubber surface, which can hinder the penetration of oxygen molecules and effectively improve the aging resistance of AEM rubber. Table 2 shows the effect of adding different contents of inorganic hollow microspheres on the decrease rate of tensile strength and elongation at break of AEM rubber under the condition of aging for 168h in air at 180℃.

[0069] The influence of the content of inorganic hollow microspheres in the diaphragm material on the aging resistance of the diaphragm is as follows:

[0070] The test method is to determine the tensile strength and elongation at break according to ASTM D412-2016. The specimen is in a dumbbell shape, the tensile rate is 500 mm / min, and each group of samples is tested 5 times to take the average value.

[0071] Table 2

[0072] Hollow glass microsphere addition amount (wt%) 0 5 15 20 30 40 Tensile strength decrease percentage (%) 51.7 45 39.4 38.1 35.8 32.6 Elongation at break decrease percentage (%) 75.6 69.7 65.1 53.8 47.2 42.1

[0073] As shown in Table 2, when the amount of hollow glass microspheres added is 0, the percentage decrease in tensile strength and elongation at break of the diaphragm material after aging are greater than the percentage decrease in tensile strength and elongation at break of the diaphragm material after aging when a certain amount of hollow glass microspheres is added. As the amount of inorganic hollow microspheres added increases, the percentage decrease in tensile strength and elongation at break of the diaphragm material after aging gradually decreases, and the anti-aging performance of the diaphragm material is improved. That is, under extreme environments, the modified ethylene-acrylate rubber film layer of the present application can also have good physical and chemical properties.

[0074] In some specific embodiments of the present application, the tensile strength of the modified ethylene-acrylate rubber film layer is ≥5 MPa.

[0075] That is, by adding a certain amount of inorganic hollow microspheres to ethylene-acrylate polymer to form a low-density rubber diaphragm material, the tensile strength of the modified ethylene-acrylate rubber film layer can be made ≥5MPa. Preferably, the tensile strength of the modified ethylene-acrylate rubber film layer is ≥7MPa.

[0076] Since inorganic hollow microspheres have high compressive strength, adding them to AEM rubber can effectively improve the tensile strength of AEM rubber. The diaphragm made of AEM rubber has high mechanical strength, which can ensure that the diaphragm will not be over-stretched due to excessive driving force in extreme environments. Table 3 shows the effect of the content of inorganic hollow microspheres on the tensile strength of the diaphragm material.

[0077] The influence of the content of inorganic hollow microspheres in the diaphragm material on the tensile strength of the diaphragm is as follows:

[0078] Table 3

[0079] Hollow glass microsphere addition amount (wt%) 0 5 15 20 30 40 Tensile strength(MPa) 4.3 5.6 7.1 10.2 12.4 15.9

[0080] As shown in Table 3, as the content of hollow glass microspheres increases, the tensile strength of the modified ethylene-acrylate rubber film layer increases significantly. In other words, by adding inorganic hollow microspheres to ethylene-acrylate rubber, the tensile strength of the modified ethylene-acrylate rubber film layer can be improved, ensuring the use effect of the diaphragm. Furthermore, by adjusting the amount of inorganic hollow microspheres added, a diaphragm with the desired tensile strength can be obtained.

[0081] According to some embodiments of the present application, the density of the modified ethylene-acrylate rubber film layer is 0.5 g / cm 3 ~1.1g / cm 3 , which can have a good weight reduction effect on the ethylene-acrylate rubber membrane layer, thereby improving the sound sensitivity of the diaphragm. Optionally, the density of the modified ethylene-acrylate rubber membrane layer is 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 Thus, through the above arrangement, the modified ethylene-acrylate rubber membrane layer can reduce weight by 30%-50%, which has a good weight reduction effect and greatly improves the sound sensitivity of the diaphragm.

[0082] According to one embodiment of the present application, the tensile strength of the modified ethylene-acrylate rubber film layer when broken is 2MPa to 45MPa, and the tear strength is 15N / mm to 100N / mm.

[0083] That is to say, by adding inorganic hollow microbeads to ethylene-acrylate polymer to form a low-density rubber diaphragm material, when the diaphragm material is broken, its tensile strength can be controlled within the range of 2MPa to 45MPa, and the tear strength can be controlled within the range of 15N / mm to 100N / mm. For example, the tensile strength of the modified ethylene-acrylate rubber can be 2MPa, 6MPa, 10MPa, 16MPa, 20MPa, 25MPa, 30MPa, 40MPa or 45MPa. The tear strength of the modified ethylene-acrylate rubber can be 15N / mm, 30N / mm, 45N / mm, 50N / mm, 70N / mm, 90N / mm or 100N / mm. That is, the modified ethylene-acrylate rubber film layer can have suitable mechanical properties, and the diaphragm prepared therefrom is not prone to problems such as film breakage during the use of the sound-generating device, effectively ensuring the reliability of the diaphragm.

[0084] According to one embodiment of the present application, the room temperature storage modulus of the modified ethylene-acrylate rubber membrane layer is 0.5 MPa to 35 MPa. By adding inorganic hollow microspheres to the ethylene-acrylate polymer to form a low-density rubber diaphragm material, the room temperature storage modulus of the modified ethylene-acrylate rubber membrane layer can be within the range of 0.5 MPa to 35 MPa, which can ensure that the diaphragm has good resilience.

[0085] That is to say, the diaphragm prepared using the modified ethylene-acrylate rubber film layer as raw material has excellent damping performance and resilience, the vibration system can effectively suppress polarization during the vibration sound generation process, and the consistency of the vibration system is better. The vibration consistency of each part of the diaphragm of the present application is better, which effectively reduces the distortion of the sound-generating device.

[0086] In some specific embodiments of the present application, the hardness of the modified ethylene-acrylate rubber film layer is 35A to 80A.

[0087] It should be noted that the sound-generating device may be a speaker. The speaker includes a vibration system and a magnetic circuit system that cooperates with the vibration system. The vibration system includes a diaphragm provided in the present application. The diaphragm may be a folded ring diaphragm or a flat diaphragm. The speaker using the diaphragm of the present application has the advantages of good sound effect and good durability.

[0088] In some specific embodiments of the present application, when the hardness of the diaphragm material is controlled within the range of 35A to 80A and the room temperature storage modulus is within the range of 0.5MPa to 35MPa, the F0 of the speaker can reach 500Hz to 1500Hz, thereby enabling the speaker to have excellent low-frequency performance.

[0089] In some specific embodiments of the present application, the loss factor of the modified ethylene-acrylate rubber film layer at room temperature is greater than 0.12.

[0090] Specifically, the inorganic hollow microspheres have high strength. After being filled with rubber, the density of the modified ethylene-acrylate rubber film layer decreases, and the hardness will be appropriately increased. At the same hardness, the reinforcing agent content of low-density rubber is much less than that of ordinary rubber. Since the rubber content of the modified ethylene-acrylate rubber film layer increases, the intermolecular entanglement increases, and the internal friction resistance is large, it has excellent damping performance. The loss factor of the diaphragm of the present application at room temperature is greater than 0.12. Preferably, the loss factor of the modified ethylene-acrylate rubber film layer is greater than 0.13. As a result, the diaphragm prepared from a diaphragm material with a higher damping value can have a lower impedance curve, improve the damping property of the diaphragm, and enable the vibration system to effectively suppress polarization during the vibration sound generation process, and the consistency of the vibration system is better.

[0091] In addition, the loss factor can be matched with the thickness of the diaphragm to further optimize the performance of the diaphragm. Generally, the higher the loss factor, the better the damping of the material. Improving the damping of the diaphragm material is conducive to reducing polarization during vibration, reducing product distortion, and improving listening yield. For example, the loss factor can be 0.12, 0.13, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2 or 0.25, etc.

[0092] It should be noted that the loss factor test method can be a conventional test method, for example: measured by dynamic mechanical test DMA, measured according to ASTM D5026-15 standard, tensile fixture, test temperature range -50℃~100℃, heating rate 3℃ / min

[0093] Furthermore, the diaphragm of the present application has excellent damping performance, such as Figure 1 As shown, the diaphragm can be a rectangular folded ring diaphragm. The horizontal axis is the frequency (Hz), and the vertical axis is the loudness displacement (mm). Points are taken at the edge position and the center position of the center of the diaphragm for testing, and test curves of vibration displacement of different parts of the diaphragm at different frequencies are obtained.

[0094] The effect of adding inorganic hollow microspheres to the diaphragm material on the damping properties of the diaphragm is as follows:

[0095] The inorganic hollow microspheres herein are hollow glass microspheres. It should be noted that hollow glass microspheres are a type of inorganic hollow microspheres. The use of hollow glass microspheres or other inorganic hollow microspheres can also reflect the role of inorganic hollow microspheres in the material.

[0096] like Figure 1 As shown, Figure 1The various curves in the figure are concentratedly distributed, which indicates that the vibration consistency of various parts of the diaphragm of the sound-emitting device of the present application is better, the diaphragm swings less during the vibration process, and the sound quality and listening stability are better.

[0097] According to one embodiment of the present application, the density of the diaphragm is 0.5 g / cm 3 ~1g / cm 3 .

[0098] That is to say, by adding inorganic hollow microspheres to ethylene-acrylate polymer to form a low-density rubber diaphragm material, and then adjusting the amount of inorganic hollow microspheres added, the density of the diaphragm can be controlled at 0.5g / cm 3 ~1g / cm 3 For example, the density of the diaphragm can be 0.5 g / cm 3 , 0.7g / cm 3 , 0.8g / cm 3 , 0.9g / cm 3 or 1g / cm 3 .

[0099] The influence of the content of inorganic hollow microspheres in the diaphragm material on the intermediate frequency Fr of the diaphragm is as follows:

[0100] like Figure 2 As shown in the figure, by testing the intermediate frequency Fr of the sound-generating device with diaphragms of different densities, as the density of the diaphragm increases, the intermediate frequency performance of the sound-generating device with it gradually decreases. In other words, by adding the diaphragm material formed by inorganic hollow microbeads to ethylene-acrylate rubber, the density of the diaphragm can be reduced and the intermediate frequency performance of the sound-generating device can be improved.

[0101] It should be noted that when the density of the low-density rubber is low (<0.5 g / cm 3 ), the content of inorganic hollow microspheres is high, the elongation at break and strength of the prepared diaphragm are low, and reliability problems such as collapse and rupture are prone to occur. When the content of inorganic hollow microspheres is low and the diaphragm density is high (>1g / cm 3 ), at the same thickness, the diaphragm prepared in the present application does not significantly improve the intermediate frequency Fr of the sound-emitting device compared with the conventional ethylene-acrylate rubber diaphragm.

[0102] In some specific embodiments of the present application, the glass transition temperature of the diaphragm is ≤-10°C.

[0103] That is, by adding inorganic hollow microspheres to ethylene-acrylate polymer to form a low-density rubber diaphragm material, and then adjusting the amount of inorganic hollow microspheres added, the glass transition temperature of the diaphragm can be controlled to be ≤-10°C. For example, -10°C, -15°C, -20°C, etc. Preferably, the glass transition temperature of the modified ethylene-acrylate rubber film layer can be ≤-20°C.

[0104] Therefore, by controlling the glass transition temperature of the diaphragm of the present application to ≤-10°C, the diaphragm can maintain a high elastic state at room temperature, so that the diaphragm has good resilience. When the operating temperature of the diaphragm is lower than 0°C, the speaker diaphragm can always maintain good rubber elasticity during operation, so that the speaker exhibits higher sound quality. At the same time, the risk of damage to the speaker diaphragm in a low temperature environment is reduced, and the reliability is higher. In addition, a diaphragm with a lower glass transition temperature can ensure that the modulus consistency of the diaphragm material is high when the diaphragm material works above the glass transition temperature, and the F0 of the diaphragm made of the diaphragm material has better stability over the entire temperature range.

[0105] According to one embodiment of the present application, the additives include a cross-linking agent, a reinforcing agent and an antioxidant.

[0106] Among them, the cross-linking agent is at least one of metal oxides, metal peroxides, organic oxides, organic peroxides and amine vulcanization systems; the reinforcing agent is at least one of carbon black, silicon dioxide, calcium carbonate, barium sulfate, organic montmorillonite, unsaturated carboxylic acid metal salts, talcum powder, clay, mica powder, feldspar powder, sulfates, magnetic powder and diatomaceous earth; the antioxidant is at least one of antioxidant N-445, antioxidant 246, antioxidant 4010, antioxidant SP, antioxidant RD, antioxidant ODA, antioxidant OD and antioxidant WH-02.

[0107] In some specific embodiments of the present application, the content of the crosslinking agent is 0.5wt% to 4.6wt% of the rubber mix, the content of the reinforcing agent is 5wt% to 71wt% of the rubber mix, and the content of the antioxidant is 0.1wt% to 5.9wt% of the rubber mix.

[0108] The content of the crosslinking agent accounts for 0.5wt% to 4.6wt% of the rubber compound, preferably 1wt% to 3wt%. The amount of the crosslinking agent directly determines the degree of crosslinking. When the content of the crosslinking agent in the system is less than 0.5wt%, the crosslinking degree of the rubber is low, the mechanical strength is low, and the mechanical properties of the material are difficult to meet the product requirements. When the crosslinking agent content is greater than 4.6wt%, the crosslinking degree of the rubber is high, the elongation at break of the material is low, the toughness of the material is insufficient, and it is easy to become brittle and break during long-term use.

[0109] The content of antioxidant accounts for 0.1wt% to 5.9wt% of the mixed rubber. During the use of rubber, as time goes by, the molecular chain breaks and produces free radicals, which accelerates its own aging. Adding antioxidant can stop the self-catalytic active free radicals produced in rubber products. Too little addition will not achieve the effect of extending the service life of the product, while too much addition will cause the mechanical properties of the material to decrease due to its inability to dissolve well with the elastomer and it is difficult to disperse evenly, and it is easy to precipitate on the surface over time.

[0110] The content of reinforcing agent accounts for 5wt% to 71wt% of the mixed rubber. The reinforcing agent interacts with the rubber molecular chain through mutual entanglement, van der Waals force or hydrogen bond to form an interface. When the material is stressed, the molecular chain is easier to slide on the surface of the reinforcing agent, but it is not easy to separate from the reinforcing agent. The rubber molecules and the reinforcing agent form a strong bond that can slide, and the mechanical strength is increased. However, excessive reinforcing agent causes the tensile strength of the material to increase significantly, and the elongation at break drops sharply, which cannot meet product requirements.

[0111] According to one embodiment of the present application, the diaphragm is a single-layer structure, and the diaphragm is composed of a layer of modified ethylene-acrylate rubber membrane.

[0112] In some specific embodiments of the present application, the diaphragm is a composite layer structure, and the diaphragm includes at least one layer of modified ethylene-acrylate rubber membrane layer. That is, when the diaphragm is a composite diaphragm, it can include one layer of modified ethylene-acrylate rubber membrane layer, or multiple layers of modified ethylene-acrylate rubber membrane layers, and the multiple layers of modified ethylene-acrylate rubber membrane layers can be arranged adjacent to each other or at intervals, and the specific arrangement method can be selected according to the specific design requirements of the sound-generating device.

[0113] According to one embodiment of the present application, the diaphragm further includes a membrane layer made of at least one of a thermoplastic elastomer, an engineering plastic, and a thermosetting elastomer.

[0114] Among them, the thermoplastic elastomer is at least one of thermoplastic polyester elastomer, thermoplastic polyurethane elastomer, thermoplastic polyamide elastomer and silicone elastomer, the engineering plastic is at least one of polyetheretherketone, polyarylate, polyetherimide, polyimide, polyphenylene sulfide, polyethylene naphthalate, polyethylene terephthalate and polybutylene terephthalate; the thermosetting elastomer is at least one of natural rubber, styrene-butadiene rubber, butadiene rubber, isoprene rubber, chloroprene rubber, butyl rubber, nitrile rubber, chlorinated nitrile rubber, ethylene-propylene rubber, silicone rubber, fluorosilicone rubber, fluororubber, polyurethane rubber, acrylate rubber, ethylene-acrylate rubber, ethylene-vinyl acetate rubber, chlorosulfonated polyethylene rubber, chloroether rubber and polysulfide rubber.

[0115] That is to say, when the diaphragm is a composite diaphragm, the composite diaphragm is composed of a film layer made of at least one of thermoplastic polyester elastomer, thermoplastic polyurethane elastomer, thermoplastic polyamide elastomer and silicone elastomer and a modified ethylene-acrylate rubber film layer. There can be a variety of raw materials for plastic polyurethane elastomer, thermoplastic polyamide elastomer and silicone elastomer, which can be selected according to specific needs. The composite diaphragm composed of a film layer made of plastic polyurethane elastomer, thermoplastic polyamide elastomer and silicone elastomer and a modified ethylene-acrylate rubber film layer has excellent mechanical properties, and while being able to ensure a certain mechanical strength, it also has a high damping value.

[0116] In summary, the diaphragm of the sound-emitting device according to the embodiment of the present application is prepared by using a modified ethylene-acrylate rubber film layer as a raw material, which not only has excellent damping performance and resilience, but the vibration system can effectively suppress polarization during the vibration sound generation process, and the consistency of the vibration system is better, which effectively reduces the distortion of the sound-emitting device. In addition, by controlling the amount of inorganic hollow microbeads added, the density of the diaphragm is reduced, and the diaphragm has excellent aging resistance and mucous membrane resistance, thereby improving the mid-frequency performance and usage performance of the sound-emitting device.

[0117] 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.

[0118] According to the second 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.

[0119] like Figure 3 and Figure 4 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 ethylene-acrylate rubber membrane layer can be applied to the folding ring portion 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.

[0120] like Figure 5 and Figure 6 As shown, according to the third aspect of the embodiment 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.

[0121] 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, namely, a first diaphragm 12 and a second diaphragm 13. The first diaphragm 12 may be used to vibrate and generate sound, and the second diaphragm 13 may be used to balance 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 generate sound 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 polarizing, thereby improving the sound-generating effect of the sound-generating device 100.

[0122] 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.

[0123] The diaphragm of the sound-generating device of the present application is described in detail below in conjunction with specific embodiments.

[0124] Comparative Example 1

[0125] The formula is as follows by weight: 100 parts of ethylene-acrylate polymer (AEM); 30 parts of reinforcing agent; 2 parts of anti-chemical agent; 2 parts of vulcanizing agent; 2 parts of vulcanization accelerator. After mixing, cross-linking reaction is carried out to form a diaphragm material, and then assembled into a product.

[0126] Embodiment 1

[0127] The formula is as follows by weight: 100 parts of ethylene-acrylate polymer (AEM); 30 parts of reinforcing agent; 30 parts of hollow glass microspheres; 2 parts of chemical inhibitor; 2 parts of vulcanizing agent; 2 parts of vulcanization accelerator. After mixing, cross-linking reaction is carried out to form a diaphragm material, which is assembled into a product.

[0128] Table 4

[0129]

[0130] Test indicators: tensile strength, elongation at break, loss factor, density and surface contact angle

[0131] As shown in Table 4, Table 4 shows the performance test results of the diaphragms of Comparative Example 1 and Example 1, reflecting the effect of adding inorganic hollow microspheres on tensile strength, elongation at break, loss factor, density and surface contact angle.

[0132] It can be seen from Table 4 that the tensile strength and loss factor of the modified ethylene-acrylate rubber film layer are significantly increased due to the addition of hollow glass microspheres. In other words, by adding inorganic hollow microspheres, the diaphragm can have excellent damping performance and resilience, the vibration system can effectively suppress polarization during the vibration sound generation process, the consistency of the vibration system is better, and the distortion of the sound generation device is effectively reduced.

[0133] Furthermore, due to the low density of hollow glass microspheres, the density of the modified ethylene-acrylate rubber film layer was significantly reduced to 0.923 g / cm 3 Moreover, the surface contact angle between the rubber film layer of the embodiment of the present application and water is 83°, while the surface contact angle between the rubber film layer of the comparative example 1 and water is 68°. Therefore, the rubber film layer of the present embodiment is easier to demold than the rubber film layer without adding inorganic hollow microspheres.

[0134] 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 of a sound-generating device, It is characterized in that The diaphragm includes at least one modified ethylene-acrylate rubber film layer, which is prepared by mixing inorganic hollow microspheres, additives and ethylene-acrylate polymer to form a mixed rubber and then performing a cross-linking reaction; The particle size of the inorganic hollow microspheres is 1 μm to 60 μm, and the distribution density of the inorganic hollow microspheres in the modified ethylene-acrylate rubber film layer is 0.15 g / cm 3 ~0.9g / cm 3 , the surface contact angle between the modified ethylene-acrylate rubber film layer and water is ≥70°; The tensile strength of the modified ethylene-acrylate rubber film layer is ≥5MPa, and the glass transition temperature of the modified ethylene-acrylate rubber film layer is ≤-10°C.

2. The diaphragm of the sound-generating device according to claim 1, It is characterized in that The content of the inorganic hollow microspheres accounts for 5wt% to 48wt% of the total amount of the mixed rubber.

3. The diaphragm of the sound-generating device according to claim 1, It is characterized in that After the modified ethylene-acrylate rubber film layer is aged in hot air at 180° C. for 168 hours, the tensile strength of the modified ethylene-acrylate rubber film layer decreases by ≤46%, and the elongation at break decreases by ≤71%.

4. The diaphragm of the sound-generating device according to claim 1, It is characterized in that The compressive strength of the inorganic hollow microspheres is ≥10MPa.

5. The diaphragm of the sound-generating device according to claim 1, It is characterized in that The loss factor of the modified ethylene-acrylate rubber film layer at room temperature is greater than 0.

12.

6. The diaphragm of the sound-generating device according to claim 1, It is characterized in that The density of the modified ethylene-acrylate rubber film layer is 0.5 g / cm 3 ~1.1g / cm 3 .

7. The diaphragm of the sound-generating device according to claim 1, It is characterized in that The additives include crosslinking agents, reinforcing agents and antioxidants. Wherein, the cross-linking agent is at least one of metal oxides, metal peroxides, organic oxides, organic peroxides and amine vulcanization systems; the reinforcing agent is at least one of carbon black, silicon dioxide, calcium carbonate, barium sulfate, organic montmorillonite, unsaturated carboxylic acid metal salts, talcum powder, clay, mica powder, feldspar powder, sulfates, magnetic powder and diatomaceous earth; the antioxidant is at least one of antioxidant N-445, antioxidant 246, antioxidant 4010, antioxidant SP, antioxidant RD, antioxidant ODA, antioxidant OD and antioxidant WH-02.

8. The diaphragm of the sound-generating device according to claim 7, It is characterized in that The content of the cross-linking agent accounts for 0.5wt% to 4.6wt% of the rubber mix, the content of the reinforcing agent accounts for 5wt% to 71wt% of the rubber mix, and the content of the antioxidant accounts for 0.1wt% to 5.9wt% of the rubber mix.

9. The diaphragm of the sound-generating device according to claim 1, It is characterized in that The diaphragm is a single-layer structure, and the diaphragm is composed of a layer of the modified ethylene-acrylate rubber film.

10. The diaphragm of the sound-generating device according to claim 1, It is characterized in that The diaphragm is a composite layer structure, and the diaphragm also includes a membrane layer made of at least one of thermoplastic elastomer, engineering plastic and thermosetting elastomer.

11. A sound-generating device, It is characterized in that It comprises a vibration system and a magnetic circuit system matched with the vibration system, the vibration system comprises 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 sound, and the diaphragm is the diaphragm described in any one of claims 1-10.

12. A sound-generating device, It is 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 1-10.

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