Diaphragm of a sound generating device and the 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 hydrogenated nitrile rubber film layer, and the modified hydrogenated nitrile rubber film layer is prepared by crosslinking reaction after mixing an inorganic hollow microsphere, an additive and a hydrogenated nitrile polymer to form a mixed rubber; wherein, the particle size of the inorganic hollow microsphere is 1 μm to 60 μm, the distribution density of the inorganic hollow microsphere in the modified hydrogenated nitrile rubber film layer is 0.15 g / cm<supgt;3< / supgt> to 0.9 g / cm<supgt;3< / supgt>, and after the modified hydrogenated nitrile rubber film layer is immersed in at least one solvent of alcohol and ethyl acetate for 72 h, its volume expansion rate ≤ 9%. In the present application, after mixing an inorganic hollow microsphere, an additive and a hydrogenated nitrile polymer to form a mixed rubber, a crosslinking reaction is carried out to form a modified hydrogenated nitrile rubber film layer, and this is used as the diaphragm material. This not only can reduce the density of the diaphragm material and improve the mid-frequency sensitivity of the sound generating device, but also enables the diaphragm material to have excellent aging resistance and solvent swelling resistance.

Description

Technical Field

[0001] The present application relates to the field of electroacoustic technologies, 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, diaphragms made of rubber materials have also been widely used in the field of speakers. However, due to the high density (≥1.2 g / cm 3 ) and relatively thick thickness of the rubber diaphragm, the mass of the diaphragm is large, resulting in a high vibration mass in the vibration system of the rubber diaphragm, and a low mid-frequency Fr (frequency response) of the sound generating device.

[0003] In addition, when the rubber diaphragm is immersed in solvents such as alcohol and ethyl acetate for a long time, the volume will expand too much. That is to say, when the conventional rubber diaphragm comes into contact with solvents such as alcohol and ethyl acetate during use, it is extremely easy to swell, and the performance drops significantly, which will not only lead to a reduction in the use effect of the diaphragm, but even make it impossible to use.

[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 of a sound generating device.

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

[0007] To achieve the above objects, the present application provides the following technical solutions.

[0008] The diaphragm of the sound generating device according to the first aspect embodiment of the present application, the diaphragm includes at least one layer of modified hydrogenated nitrile rubber film layer, and the modified hydrogenated nitrile rubber film layer is prepared by cross-linking reaction after kneading inorganic hollow microspheres, additives and hydrogenated nitrile polymer to form a kneaded 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 diaphragm is 0.15 g / cm 3 to 0.9 g / cm 3 , and after the modified hydrogenated nitrile rubber film layer is immersed in at least one of alcohol and ethyl acetate for 72 h, the volume expansion rate of the modified hydrogenated nitrile rubber film layer ≤ 9%.

[0009] According to some embodiments of the present application, the compressive strength of the inorganic hollow microspheres ≥ 10 MPa.

[0010] According to some embodiments of the present application, the density of the modified hydrogenated nitrile rubber film layer is 0.5 g / cm3 ~1.1 g / cm 3 。

[0011] According to some embodiments of the present application, the content of the inorganic hollow microspheres accounts for 5 wt% to 51 wt% of the total amount of the mixed rubber.

[0012] According to some embodiments of the present application, after the modified hydrogenated nitrile rubber film layer is aged in hot air at 165 °C for 168 h, the tensile strength of the modified hydrogenated nitrile rubber film layer decreases by ≤60%, and the elongation at break decreases by ≤80%.

[0013] According to some embodiments of the present application, the tensile strength at break of the modified hydrogenated nitrile rubber film layer is 2 MPa to 45 MPa, and the tear strength is 15 N / mm to 100 N / mm.

[0014] According to some embodiments of the present application, the room temperature storage modulus of the modified hydrogenated nitrile rubber film layer is 0.5 MPa to 35 MPa.

[0015] According to some embodiments of the present application, the loss factor of the modified hydrogenated nitrile rubber film layer at room temperature > 0.12.

[0016] According to some embodiments of the present application, the additives include a crosslinking agent, a reinforcing agent, and an anti-aging agent. Among them, the crosslinking agent is at least one of a sulfur-based vulcanizing agent and a peroxide-based vulcanizing agent; the reinforcing agent is at least one of carbon black, silica, calcium carbonate, barium sulfate, organic montmorillonite, unsaturated carboxylic acid metal salts, talc powder, clay, mica powder, feldspar powder, sulfates, magnetic powder, and diatomaceous earth; the anti-aging agent is at least one of anti-aging agent N-445, anti-aging agent 246, anti-aging agent 4010, anti-aging agent SP, anti-aging agent RD, anti-aging agent ODA, anti-aging agent OD, and anti-aging agent WH-02.

[0017] According to some embodiments of the present application, the content of the crosslinking agent accounts for 0.5 wt% to 5.5 wt% of the mixed rubber, the content of the reinforcing agent accounts for 5 wt% to 65 wt% of the mixed rubber, and the content of the anti-aging agent accounts for 0.1 wt% to 6.2 wt% of the mixed rubber.

[0018] According to some embodiments of the present application, the vibrating membrane is a single-layer structure, and the vibrating membrane is composed of one layer of the modified hydrogenated nitrile rubber film layer.

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

[0020] The sound generating device according to the second aspect embodiment of the present application includes a vibration system and a magnetic circuit system cooperating with the vibration system. The vibration system includes a diaphragm and a voice coil bonded to one side of the diaphragm. The magnetic circuit system drives the voice coil to vibrate to drive the diaphragm to generate sound. The diaphragm is the diaphragm according to the above embodiment of the present application.

[0021] The sound generating device according to the third aspect embodiment of the present application includes a housing and a magnetic circuit system and a vibration system provided in the housing. 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 generate sound. Both ends of the second diaphragm are respectively connected to the housing and the bottom of the voice coil. The second diaphragm is the diaphragm according to the above embodiment of the present application.

[0022] For the diaphragm of the sound generating device according to the embodiment of the present application, after mixing inorganic hollow microspheres, additives, and hydrogenated nitrile polymer to form a mixed rubber, a cross-linking reaction is carried out to form a modified hydrogenated nitrile rubber film layer, and this is used as the diaphragm material. It can not only reduce the density of the diaphragm material and improve the mid-frequency sensitivity of the sound generating device, but also make the diaphragm material have excellent aging resistance and solvent swelling resistance, effectively improving the service life of the diaphragm.

[0023] Through the following detailed description of the exemplary embodiments of the present application with reference to the accompanying drawings, other features and advantages of the present application will become clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings incorporated in the specification and constituting a part of the specification illustrate the embodiments of the present application and, together with the description, are used to explain the principles of the present application.

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

[0026] Figure 2 It is the mid-frequency Fr curve of the modified hydrogenated nitrile rubber film layer with different densities of the diaphragm of the sound generating device according to the embodiment of the present application;

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

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

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

[0030] Figure 6 Exploded view of the 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; surround portion 151; dome top 152. Detailed implementation manners

[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 arrangements of components and steps, numerical expressions and 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 a limitation on the present application or its application or use.

[0037] Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be regarded as part of the specification.

[0038] In all the examples shown and discussed herein, any specific values should be construed as merely exemplary and not as a limitation. Thus, other examples of the exemplary embodiments may have different values.

[0039] It should be noted that: Similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0040] The diaphragm of the sound generating device according to an embodiment of the present application will now be specifically described with reference to the accompanying drawings.

[0041] The diaphragm of the sound generating device according to an embodiment of the present application, the diaphragm includes at least one layer of modified hydrogenated nitrile rubber film layer, and the modified hydrogenated nitrile rubber film layer is prepared by cross-linking reaction after mixing inorganic hollow microspheres, additives and hydrogenated nitrile polymer to form a mixed rubber. Among them, 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 hydrogenated nitrile rubber film layer is 0.15 g / cm 3 ~0.9 g / cm 3 , after the modified hydrogenated nitrile rubber film layer is immersed in at least one solvent of alcohol and ethyl acetate for 72 h, the volume expansion rate of the modified hydrogenated nitrile rubber film layer ≤ 9%.

[0042] The diaphragm of the sound generating device according to the embodiments of the present application may be composed of at least one layer of modified hydrogenated nitrile rubber film layer. Specifically, the diaphragm in the present application may 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 one layer of the modified hydrogenated nitrile rubber film layer of the present application. When the diaphragm is a multi-layer composite structure, the diaphragm includes at least one layer of modified hydrogenated nitrile rubber film layer, and the diaphragm is formed by laminating the modified hydrogenated nitrile rubber film layer with a film layer of other materials. Optionally, when there are multiple layers of modified hydrogenated nitrile rubber film layers in the diaphragm, the adjacent two layers of modified hydrogenated nitrile rubber film layers may be spaced apart, that is, a film layer of other materials may also be provided between the adjacent two layers of modified hydrogenated nitrile rubber film layers. Of course, the adjacent two layers of modified hydrogenated nitrile rubber film layers may also be laminated together, and it can be selected according to actual usage requirements, and the present application does not make specific restrictions on this.

[0043] Specifically, the chemical formula of the hydrogenated nitrile polymer may be the following formula (Ⅰ).

[0044]

[0045] In formula (Ⅰ): l1, l2, m, and n are natural numbers.

[0046] Among them, the modified hydrogenated nitrile rubber film layer is made by adding inorganic hollow microspheres to the hydrogenated nitrile polymer. After mixing the inorganic hollow microspheres, additives and hydrogenated nitrile polymer, a mixed rubber can be formed, and the modified hydrogenated nitrile rubber can be formed after vulcanizing the mixed rubber. That is to say, the hydrogenated nitrile polymer can form hydrogenated nitrile rubber, and the hydrogenated nitrile rubber is equivalent to the base material. After the inorganic hollow microspheres and the hydrogenated nitrile polymer go through the mixing process, the inorganic hollow microspheres can be dispersed in the base material. Since the density of the inorganic hollow microspheres is less than the density of the rubber, by adding inorganic hollow microspheres to the hydrogenated nitrile polymer, the density of the modified hydrogenated nitrile rubber film layer can be reduced, and a diaphragm with a low density can be obtained.

[0047] Under the condition that the modified hydrogenated nitrile rubber film layer of the present application has the same hardness as the conventional hydrogenated nitrile rubber film layer, 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 mid-frequency frequency response of the sound generating device, so that the sound generating device has a higher mid-frequency sensitivity.

[0048] The inorganic hollow microspheres are hollow, thin-walled, hard and lightweight spheres, and they have 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, so that the overall weight of the diaphragm is reduced, the vibration mass of the vibration system is reduced, and the sensitivity of the sound generating device is improved. 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, and it has high heat resistance.

[0049] Inorganic hollow microspheres are added to HNBR (hydrogenated nitrile butadiene) rubber, and a dense protective layer can be formed on the rubber surface, hindering the infiltration of oxygen molecules and effectively improving the aging resistance of HNBR rubber. At the same time, the inorganic hollow microspheres have relatively high compressive strength, which can ensure that the inorganic hollow microspheres are not crushed during the mixing process.

[0050] Furthermore, the particle size of the inorganic hollow microspheres can be selected within 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. That is to say, inorganic hollow microspheres with different particle sizes can be selected according to the different thicknesses of the diaphragm to ensure the uniform dispersion of the inorganic hollow microspheres in the substrate.

[0051] In addition, as the size of the inorganic hollow microspheres decreases, the distribution density of the inorganic hollow microspheres in the modified hydrogenated nitrile butadiene rubber film layer will show an increasing trend. By selecting the appropriate size of the inorganic hollow microspheres, the distribution density of the inorganic hollow microspheres in the modified hydrogenated nitrile butadiene rubber film layer can be controlled within the range of 0.15 g / cm 3 ~0.9 g / cm 3 For example, the distribution density of the inorganic hollow microspheres can be 0.15 g / cm 3 、0.2 g / cm 3 、0.35 g / cm 3 、0.5 g / cm 3 、0.6 g / cm 3 、0.7 g / cm 3 、0.8 g / cm 3 or 0.9 g / cm 3 。To ensure that the inorganic hollow microspheres can effectively reduce the diaphragm density, the distribution density of the inorganic hollow microspheres is preferably 0.35 g / cm 3 ~0.8 g / cm 3 。

[0052] It should be noted that since the inorganic hollow microspheres are inorganic materials, they have excellent solvent resistance. And when the inorganic hollow microspheres are added to the hydrogenated nitrile butadiene polymer, the molecular chains of HNBR and the inorganic hollow microspheres can form a wrapped and entangled structure, effectively reducing the free volume of the molecules and hindering the infiltration of the solvent. Therefore, the modified hydrogenated nitrile butadiene rubber film layer has excellent solvent swelling resistance.

[0053] Specifically, after the modified hydrogenated nitrile butadiene rubber film layer is immersed in at least one of alcohol and ethyl acetate for 72 h, the volume expansion rate of the modified hydrogenated nitrile butadiene rubber film layer is ≤9%, preferably ≤6%. Table 1 shows the volume expansion rates of modified hydrogenated nitrile butadiene rubber film layers with different contents of inorganic hollow microspheres. The inorganic hollow microspheres here are selected as hollow glass microspheres. It should be noted that hollow glass microspheres are one kind of inorganic hollow microspheres. Whether using hollow glass microspheres or other inorganic hollow microspheres can equally 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 volume expansion rate of the diaphragm material is as follows:

[0055] Table 1

[0056] Addition amount of hollow glass microspheres (wt%) 0 5 15 20 30 40 Volume expansion rate (%) 10.69 8.78 5.96 4.31 3.64 2.23

[0057] As shown in Table 1, the volume expansion rate of HNBR rubber with a hollow glass microsphere addition of 0 is 10.69%, which is greater than 10%. As the addition amount of hollow glass microspheres increases, the volume expansion rate of the modified hydrogenated nitrile butadiene rubber film layer gradually decreases and is less than 9%. That is to say, by adding a certain content of inorganic hollow microspheres to HNBR rubber as the diaphragm material, the solvent swelling resistance of the diaphragm material can be effectively improved, and further the service life of the diaphragm is improved.

[0058] Thus, for the diaphragm of the sound generating device according to the embodiment of the present application, after the inorganic hollow microspheres, additives and hydrogenated nitrile polymer are kneaded to form a kneaded rubber, a cross-linking reaction is carried out to form a modified hydrogenated nitrile butadiene rubber film layer, and this is used as the diaphragm material. It can not only reduce the density of the diaphragm material and improve the mid-frequency sensitivity of the sound generating device, but also make the diaphragm material have excellent aging resistance and solvent swelling resistance, effectively improving the service life of the diaphragm.

[0059] According to an embodiment of the present application, the compressive strength of the inorganic hollow microspheres ≥10 MPa.

[0060] That is to say, the inorganic hollow microspheres have a relatively high compressive strength, which can not only ensure that the inorganic hollow microspheres are not crushed by extrusion during the kneading process, but also when added to HNBR rubber, can effectively improve the tensile strength of the modified hydrogenated nitrile butadiene rubber film layer. When the diaphragm has a relatively high mechanical strength, it can ensure that the diaphragm will not be over-stretched due to excessive driving force in an extreme environment, further ensuring the use effect of the diaphragm.

[0061] In some specific embodiments of the present application, the content of the inorganic hollow microspheres accounts for 5 wt% - 51 wt% of the total amount of the kneaded rubber.

[0062] That is to say, inorganic hollow microspheres accounting for 5wt% - 51wt% of the total amount of the mixed rubber can be added to the hydrogenated nitrile polymer to prepare a modified hydrogenated nitrile rubber film layer. As the addition amount of the inorganic hollow microspheres increases, the density of the modified hydrogenated nitrile rubber film layer decreases. By controlling the addition amount of the inorganic hollow microspheres, a diaphragm material with desired properties can be obtained. The content of the inorganic hollow microspheres can be any value between 5wt% and 51wt%. For example, the content of the inorganic hollow microspheres can be 5wt%, 10wt%, 15wt%, 20wt%, 30wt%, 40wt% or 51wt%.

[0063] It should be noted that since the density of the inorganic hollow microspheres is much smaller than that of the rubber, as the addition amount of the inorganic hollow microspheres increases, the density of the rubber material will decrease significantly. Specifically, when the content of the 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 large density. When the content of the inorganic hollow microspheres is too high (more than 51wt%), due to its too high mechanical strength, the maximum amplitude that the prepared diaphragm can reach under the same driving force decreases, resulting in a decrease in the low-frequency Fr of the sound generating device. Moreover, excessive addition of inorganic hollow microspheres will cause a significant decrease in the density of the modified hydrogenated nitrile rubber film layer, and the prepared diaphragm has low elongation at break and strength, and reliability problems such as collapse and film breakage are likely to occur.

[0064] Therefore, by using the modified hydrogenated nitrile rubber film layer prepared by adding inorganic hollow microspheres accounting for 5wt% - 51wt% of the total amount of the mixed rubber as the diaphragm material, the density and strength of the diaphragm can be taken into account at the same time, effectively ensuring the excellent medium-frequency and low-frequency performance of the diaphragm.

[0065] According to an embodiment of the present application, after the modified hydrogenated nitrile rubber film layer is aged in hot air at 165°C for 168h, the tensile strength of the modified hydrogenated nitrile rubber film layer decreases by ≤60%, and the elongation at break decreases by ≤80%.

[0066] Specifically, the chemical composition of the hollow glass microspheres is borosilicate, which has high heat resistance. When it is added to the hydrogenated nitrile polymer, a dense oxide layer is formed on the surface of the rubber, which can prevent the infiltration of oxygen molecules and effectively improve the aging resistance of the modified hydrogenated nitrile rubber film layer. Table 2 shows the effects of different contents of inorganic hollow microspheres on the tensile strength reduction rate and elongation at break reduction rate of HNBR rubber under the condition of aging in hot air at 165°C for 168h.

[0067] The influence of the content of inorganic hollow microspheres in the diaphragm material on the aging resistance of the diaphragm is as follows:

[0068] Testing method: The tensile strength and elongation at break are determined according to the ASTM D412-2016 standard. The specimen shape is dumbbell-shaped, the tensile rate is 500 mm / min, and each group of samples is tested 5 times and the average value is taken.

[0069] Table II

[0070] Addition amount of hollow glass microspheres (wt%) 0 5 15 20 30 40 Percentage decrease in tensile strength (%) 65.8 58.4 47.3 41.2 39.6 38.7 Percentage decrease in elongation at break (%) 86.1 78.2 63.9 52.5 47.3 43.6

[0071] As shown in Table II, the percentage decrease in tensile strength and the percentage decrease in elongation at break of the diaphragm material when the addition amount of hollow glass microspheres is 0 after aging are greater than those of the diaphragm material with a certain content of hollow glass microspheres added after aging. As the addition amount of hollow glass microspheres increases, the percentage decrease in tensile strength and the percentage decrease in elongation at break of the diaphragm material after aging gradually decrease, and the anti-aging performance of the diaphragm material is improved. That is, in extreme environments, the diaphragm material of the present application can still have good physical and chemical properties.

[0072] According to an embodiment of the present application, the tensile strength at break of the modified hydrogenated nitrile rubber film layer is 2 MPa to 45 MPa, and the tear strength is 15 N / mm to 100 N / mm.

[0073] That is to say, by adding inorganic hollow microspheres to the hydrogenated nitrile 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 2 MPa to 45 MPa, and the tear strength can be controlled within the range of 15 N / mm to 100 N / mm. For example, the tensile strength of the modified hydrogenated nitrile rubber film layer can be 2 MPa, 6 MPa, 10 MPa, 16 MPa, 20 MPa, 25 MPa, 30 MPa, 40 MPa or 45 MPa. The tear strength of the modified hydrogenated nitrile rubber film layer can be 15 N / mm, 30 N / mm, 45 N / mm, 50 N / mm, 70 N / mm, 90 N / mm or 100 N / mm. That is, the modified hydrogenated nitrile rubber film layer can have appropriate 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 use.

[0074] According to an embodiment of the present application, the room temperature storage modulus of the modified hydrogenated nitrile rubber film layer is 0.5 MPa to 35 MPa. By adding inorganic hollow microspheres to the hydrogenated nitrile polymer to form a low-density rubber diaphragm material, the room temperature storage modulus of the modified hydrogenated nitrile rubber film layer can be within the range of 0.5 MPa to 35 MPa, which can ensure that the diaphragm has good resilience.

[0075] That is to say, the diaphragm prepared by using the modified hydrogenated nitrile rubber film layer has excellent damping performance and resilience. The vibration system can effectively suppress the polarization phenomenon 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, effectively reducing the distortion of the sound generating device.

[0076] In some specific embodiments of the present application, the hardness of the modified hydrogenated nitrile rubber film layer is 35A - 80A.

[0077] It should be noted that the sound generating device can be a loudspeaker. The loudspeaker includes a vibration system and a magnetic circuit system that cooperates with the vibration system. The vibration system includes the diaphragm provided by the present application, and the diaphragm can be a surround diaphragm or a flat diaphragm. The loudspeaker using the diaphragm of the present application has advantages such as good sound generating effect and good durability.

[0078] In some specific embodiments of the present application, when the hardness of the diaphragm material is controlled within the range of 35A - 80A and the room temperature storage modulus is within the range of 0.5 MPa - 35 MPa, the F0 of the loudspeaker can reach 500 Hz - 1500 Hz, so that the loudspeaker has excellent low-frequency performance.

[0079] In some specific embodiments of the present application, the loss factor of the modified hydrogenated nitrile rubber film layer at room temperature > 0.12.

[0080] Specifically, the inorganic hollow microspheres have relatively high strength. After being filled into the rubber, the density of the modified hydrogenated nitrile rubber film layer decreases, and the hardness will be appropriately increased. At the same hardness, the content of the reinforcing agent in the low-density rubber is much less than that of the ordinary rubber. The rubber content of the modified hydrogenated nitrile rubber film layer increases, the entanglement between molecules increases, and the internal frictional resistance is large, having 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 hydrogenated nitrile rubber film layer > 0.13. Thus, the diaphragm prepared from the diaphragm material with a relatively high damping value can have a lower impedance curve, improve the damping of the diaphragm, so that the vibration system can effectively suppress the polarization phenomenon during the vibration sound generation process, and the consistency of the vibration system is better.

[0081] In addition, the loss factor can be coordinated with the thickness of the diaphragm, which can further optimize the performance of the diaphragm. Generally, the higher the loss factor, the better the damping property of the material. The improvement of the damping property of the diaphragm material is beneficial to reducing the polarization during the vibration process, reducing the product distortion, and improving the listening yield. For example, the loss factor can be 0.12, 0.13, 0.15, 0.16, 0.17 or 0.18, etc.

[0082] It should be noted that the loss factor test method can be a conventional test method. For example, it can be obtained by dynamic mechanical analysis (DMA) and measured according to the ASTM D5026-15 standard. A tensile fixture is used, the test temperature range is -50°C to 100°C, and the heating rate is 3°C / min.

[0083] Furthermore, the diaphragm of the present application has excellent damping performance, as Figure 1 shown. Among them, the diaphragm can be a rectangular surround diaphragm. The abscissa is frequency (Hz), and the ordinate 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 the test curves of the vibration displacement of different parts of the diaphragm at different frequencies are obtained.

[0084] The influence of the diaphragm material added with inorganic hollow microspheres on the damping performance of the diaphragm is as follows:

[0085] As Figure 1 shown, Figure 1 the curves in

[0086] are concentratedly distributed, which indicates that the vibration consistency of each part of the diaphragm of the sound generating device of the present application is better. During the vibration process, the diaphragm has less swaying, and the sound quality and listening stability are better. 3 ~1.1 g / cm 3 .

[0087] That is to say, by adding inorganic hollow microspheres to the hydrogenated nitrile polymer to form a low-density rubber diaphragm material, and then adjusting the addition amount of the inorganic hollow microspheres, the density of the modified hydrogenated nitrile rubber film layer can be controlled within 0.5 g / cm 3 ~1.1 g / cm 3 . For example, the density of the modified hydrogenated nitrile rubber film layer can be 0.5 g / cm 3 , 0.7 g / cm 3 , 0.8 g / cm 3 , 0.9 g / cm 3 , 1 g / cm 3 or 1.1 g / cm 3 . Thus, through the above settings, the modified hydrogenated nitrile rubber film layer can reduce weight by 30% - 50%, achieving a good weight reduction effect and greatly improving the sound generation sensitivity of the diaphragm.

[0088] Table III shows the influence of different addition amounts of inorganic hollow microspheres on the density of the hydrogenated nitrile rubber film layer.

[0089] As shown in Table III, as the addition amount of hollow glass microspheres increases, the density of the hydrogenated nitrile rubber film layer gradually decreases.

[0090] The influence of the content of inorganic hollow microspheres in the diaphragm material on the density of the diaphragm is as follows:

[0091] Table III

[0092] Addition amount of hollow glass microspheres (wt%) 0 5 10 40 50 <![CDATA[Rubber density (g / cm 3 )]]> 1.25 1.19 1.05 0.62 0.51

[0093] The influence of the content of inorganic hollow microspheres in the diaphragm material on the mid-frequency Fr of the diaphragm is as follows:

[0094] As Figure 2 shown, by testing the mid-frequency Fr of the sound generating device of diaphragms with different densities, as the density of the diaphragm increases, the mid-frequency performance of the sound generating device with it gradually decreases. That is to say, by adding inorganic hollow microspheres to the hydrogenated nitrile rubber film layer to form a modified hydrogenated nitrile rubber film layer, the density of the diaphragm can be reduced and the mid-frequency sensitivity of the sound generating device can be improved.

[0095] Among them, it should also be noted that when the density of the low-density rubber is relatively low (<0.5 g / cm 3 ), its content of inorganic hollow microspheres is relatively high, and the breaking elongation and strength of the prepared diaphragm are low, and reliability problems such as collapse and film breakage are likely to occur. When the content of inorganic hollow microspheres is relatively low and the density of the diaphragm is relatively high (>1 g / cm 3 ), under the same thickness, compared with the conventional hydrogenated nitrile rubber diaphragm prepared in this application, the weight reduction ratio is relatively small, and the improvement of the mid-frequency sensitivity of the sound generating device is not obvious.

[0096] In some specific embodiments of the present application, the glass transition temperature of the modified hydrogenated nitrile rubber film layer ≤ -10 °C.

[0097] That is to say, by adding inorganic hollow microspheres to the hydrogenated nitrile polymer to form a low-density rubber diaphragm material, and then adjusting the addition amount of the inorganic hollow microspheres, the glass transition temperature of the modified hydrogenated nitrile rubber film layer can be controlled at ≤ -10 °C. For example, -10 °C, -15 °C, -20 °C, etc. Preferably, the glass transition temperature of the modified hydrogenated nitrile rubber film layer can be ≤ -20 °C.

[0098] Thus, by controlling the glass transition temperature of the modified hydrogenated nitrile rubber film layer of the present application to be ≤ -10 °C, the modified hydrogenated nitrile rubber film layer can maintain a high elastic state at room temperature, enabling the diaphragm to have 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 high 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. Moreover, for a diaphragm with a low glass transition temperature, when the diaphragm material works above the glass transition temperature, the modulus of the diaphragm material is highly consistent, and the F0 of the diaphragm prepared from this diaphragm material has better stability in the full temperature range.

[0099] According to an embodiment of the present application, the additive includes a crosslinking agent, a reinforcing agent, and an antioxidant.

[0100] Among them, the crosslinking agent is at least one of sulfur-based vulcanizing agents and peroxide-based vulcanizing agents; the reinforcing agent is at least one of carbon black, silica, calcium carbonate, barium sulfate, organic montmorillonite, metal unsaturated carboxylates, talc, 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.

[0101] In some specific embodiments of the present application, the content of the crosslinking agent accounts for 0.5 wt% - 5.5 wt% of the mixed rubber, the content of the reinforcing agent accounts for 5 wt% - 65 wt% of the mixed rubber, and the content of the antioxidant accounts for 0.1 wt% - 6.2 wt% of the mixed rubber.

[0102] Among them, the content of the crosslinking agent accounts for 0.5 wt% - 5.5 wt% of the mixed rubber, preferably 1 wt% - 3 wt%. The dosage of the crosslinking agent directly determines the degree of crosslinking. When the content of the crosslinking agent in the system is lower than 0.5 wt%, 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 content of the crosslinking agent is greater than 5.5 wt%, 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 brittlely fracture during long-term use.

[0103] The content of the antioxidant accounts for 0.1 wt% - 6.2 wt% of the mixed rubber. During the use of rubber, as time goes by, the molecular chain breaks to generate free radicals, accelerating its own aging. Adding an antioxidant can terminate the self-catalytic active free radicals generated in rubber products. Too little addition amount of the antioxidant cannot achieve the effect of extending the service life, while too much addition amount, due to its poor mutual solubility with the elastomer and difficult uniform dispersion, leads to a decrease in the mechanical properties of the material and is prone to surface precipitation over time.

[0104] The content of the reinforcing agent accounts for 5wt% - 65wt% of the mixed rubber. The reinforcing agent forms an interfacial interaction with the rubber molecular chains through entanglement, van der Waals forces or hydrogen bonds. When the material is stressed, the molecular chains are relatively easy to slide on the surface of the reinforcing agent, but not easy to separate from the reinforcing agent. The rubber molecules and the reinforcing agent form a strong and slidable bond, increasing the mechanical strength. However, an excessive amount of the reinforcing agent leads to a significant increase in the tensile strength of the material and a sharp decrease in the elongation at break, unable to meet the product requirements.

[0105] According to an embodiment of the present application, the diaphragm is a single-layer structure, and the diaphragm is composed of a layer of modified hydrogenated nitrile rubber film layer.

[0106] In some specific embodiments of the present application, the diaphragm is a composite layer structure, and the diaphragm further includes a film layer made of at least one of a thermoplastic elastomer, an engineering plastic, and a thermosetting elastomer.

[0107] That is to say, when the diaphragm is a composite diaphragm, it includes at least one layer of modified hydrogenated nitrile rubber film layer. It may include one layer of modified hydrogenated nitrile rubber film layer, or may include multiple layers of modified hydrogenated nitrile rubber film layers. The multiple layers of modified hydrogenated nitrile rubber film layers may be arranged adjacent to each other or at intervals. The specific arrangement method can be selected according to the specific design requirements of the sound generating device.

[0108] Among them, the thermoplastic elastomer is at least one of a thermoplastic polyester elastomer, a thermoplastic polyurethane elastomer, a thermoplastic polyamide elastomer, and a silicone elastomer. The engineering plastic is at least one of polyether ether ketone, 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, cis-1,4-polybutadiene rubber, isoprene rubber, chloroprene rubber, butyl rubber, nitrile rubber, chlorinated nitrile rubber, ethylene-propylene rubber, silicone rubber, fluorosilicone rubber, fluororubber, polyurethane rubber, acrylate rubber, hydrogenated nitrile rubber, ethylene-vinyl acetate rubber, chlorosulfonated polyethylene rubber, chlorinated ether rubber, and polysulfide rubber.

[0109] Furthermore, when the diaphragm is a composite diaphragm, the composite diaphragm can be composed of a film layer made of at least one of a thermoplastic polyester elastomer, a thermoplastic polyurethane elastomer, a thermoplastic polyamide elastomer, and a silicone elastomer and a modified hydrogenated nitrile rubber film layer. There can be various choices for the raw materials of the thermoplastic polyurethane elastomer, the thermoplastic polyamide elastomer, and the silicone elastomer, which can be selected according to specific requirements. The composite diaphragm composed of a film layer made of a thermoplastic polyurethane elastomer, a thermoplastic polyamide elastomer, and a silicone elastomer and a modified hydrogenated nitrile rubber film layer has excellent mechanical properties and has a relatively high damping value while ensuring a certain mechanical strength.

[0110] In summary, the diaphragm of the sound generating device according to the embodiments of the present application, by using a modified hydrogenated nitrile rubber film layer as the raw material to prepare the diaphragm, has excellent damping performance and resilience. During the vibration and sound generation process of the vibration system, the polarization phenomenon can be effectively suppressed, the consistency of the vibration system is better, the distortion of the sound generating device is effectively reduced, and by controlling the addition amount of inorganic hollow microspheres, the density of the diaphragm is reduced, the mid-frequency Fr of the sound generating device is increased, and the diaphragm has excellent aging resistance and solvent resistance, thereby improving the service life of the diaphragm. Therefore, the sound generating device made of the diaphragm of the present application has good use effects and acoustic performance.

[0111] It should be noted that the diaphragm provided by the present application can form a sound generating device with any structure, such as the following typical sound generating devices: including a vibration system and a magnetic circuit system cooperating with the vibration system, and the vibration system includes a diaphragm and a voice coil bonded to one side of the diaphragm. When the sound generating device works, 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 generate sound when vibrating.

[0112] The sound generating device according to the second aspect embodiment of the present application includes a vibration system and a magnetic circuit system cooperating with the vibration system. The vibration system includes a diaphragm and a voice coil bonded to one side of the diaphragm. The magnetic circuit system drives the voice coil to vibrate to drive the diaphragm to generate sound, and the diaphragm is the diaphragm of the above embodiment. Specifically, when the sound generating device works, 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 generate sound when vibrating.

[0113] As Figure 3 and Figure 4 shown, the sound generating device includes a diaphragm 15 prepared by the above embodiment of the present application. The diaphragm 15 can be composed of a surround portion 151 and a dome portion 152, and the modified hydrogenated nitrile rubber film layer can be applied to the surround portion of the diaphragm. Those skilled in the art can make corresponding adjustments according to the actual product requirements, such as the surround portion 151 protruding toward the voice coil 11 side, the dome portion 152 being located on the lower surface of the surround portion 151, and adding a centering washer in the vibration system, etc.

[0114] As Figure 5 and Figure 6 shown, the sound generating device 100 according to the third aspect embodiment of the present application includes a housing 10, a magnetic circuit system 14 and a vibration system provided in the housing 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 generate sound. Both ends of the second diaphragm 13 are respectively connected to the housing 10 and the bottom of the voice coil 11, and the second diaphragm 13 is the diaphragm of the above embodiment.

[0115] That is to say, the sound generating device 100 according to the embodiments of the present application may further include two diaphragms prepared according to the above embodiments of the present application, namely, a first diaphragm 12 and a second diaphragm 13. The first diaphragm 12 may be used for vibrating to 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 works, 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 can vibrate up and down to drive the first diaphragm 12 to vibrate, and the first diaphragm 12 can generate sound when vibrating. The second diaphragm 13 can also vibrate up and down following the voice coil 11. Since both 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 can balance the vibration of the voice coil 11, and can prevent the voice coil 11 from being polarized, thereby improving the sound generating effect of the sound generating device 100.

[0116] It should be noted that both the first diaphragm 12 and the second diaphragm 13 can be made of the diaphragm according to the above embodiments of the present application, or one of the first diaphragm 12 and the second diaphragm 13 can be made of the diaphragm according to the above embodiments of the present application. The present application does not make specific limitations on this.

[0117] The diaphragm of the sound generating device of the present application will be specifically described below in conjunction with specific embodiments.

[0118] Comparative Example 1

[0119] By mass, the formula is as follows: 100 parts of hydrogenated nitrile polymer (HNBR); 40 parts of carbon black; 2 parts of anti-chemical agent; 1.5 parts of vulcanizing agent; 2.2 parts of vulcanization accelerator. After mixing, a cross-linking reaction is carried out to form a diaphragm material, and then assembled into a product.

[0120] Example 1

[0121] By mass, the formula is as follows: 100 parts of hydrogenated nitrile polymer (HNBR); 15 parts of carbon black; 25 parts of hollow glass microspheres; 2 parts of anti-chemical agent; 1.5 parts of vulcanizing agent; 2.2 parts of vulcanization accelerator. After mixing, a cross-linking reaction is carried out to form a diaphragm material, and then assembled into a product.

[0122] Table IV

[0123]

[0124] Test indicators: Tensile strength, elongation at break, loss factor, density and surface contact angle

[0125] As shown in Table IV, Table IV shows the performance test results of the diaphragms of Comparative Example 1 and Example 1, reflecting the influence of adding inorganic hollow microspheres on tensile strength, volume expansion rate, loss factor and density.

[0126] As can be seen from Table 4, with the addition of hollow glass microspheres, the tensile strength and loss factor of the modified hydrogenated nitrile rubber film layer increase significantly. That is to say, the diaphragm with inorganic hollow microspheres added has excellent damping performance and resilience. During the vibration sound generation process of the vibration system, the polarization phenomenon can be effectively suppressed, the consistency of the vibration system is better, and the distortion of the sound generating device is effectively reduced.

[0127] Furthermore, due to the low density of the hollow glass microspheres, the density of the modified hydrogenated nitrile rubber film layer decreases significantly to 1.031 g / cm 3 . Moreover, the volume expansion rate of the rubber film layer in the embodiment of the present application after soaking is only 5.43%, while the volume expansion rate of the rubber film layer in Comparative Example 1 after soaking is 10.69%. Therefore, the rubber film layer in this embodiment has excellent swelling resistance compared to the rubber film layer without inorganic hollow microspheres added.

[0128] Although some specific embodiments of the present application have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present application. Those skilled in the art should understand that the above embodiments can 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, characterized in that, The diaphragm includes at least one layer of modified hydrogenated nitrile rubber film layer, and the modified hydrogenated nitrile rubber film layer is prepared by cross-linking reaction after mixing inorganic hollow microspheres, additives and hydrogenated nitrile polymer to form a mixed rubber. Among them, 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 hydrogenated nitrile rubber film layer is 0.15 g / cm 3 ~0.9 g / cm 3 , after the modified hydrogenated nitrile rubber film layer is immersed in at least one solvent of alcohol and ethyl acetate for 72 h, the volume expansion rate of the modified hydrogenated nitrile rubber film layer ≤ 9%; The compressive strength of the inorganic hollow microspheres is ≥10 MPa, and the content of the inorganic hollow microspheres accounts for 5 wt% - 51 wt% of the total amount of the mixed rubber.

2. The diaphragm of the sound generating device according to claim 1, characterized in that, The density of the modified hydrogenated nitrile rubber film layer is 0.5 g / cm 3 ~1.1 g / cm 3 .

3. The diaphragm of the sound generating device according to claim 1, characterized in that, After the modified hydrogenated nitrile rubber film layer is aged in hot air at 165 °C for 168 h, the tensile strength reduction rate of the modified hydrogenated nitrile rubber film layer is ≤60%, and the elongation at break reduction rate is ≤80%.

4. The diaphragm of the sound generating device according to claim 1, characterized in that, The tensile strength at break of the modified hydrogenated nitrile rubber film layer is 2 MPa - 45 MPa, and the tear strength is 15 N / mm - 100 N / mm.

5. The diaphragm of the sound generating device according to claim 1, characterized in that, The room temperature storage modulus of the modified hydrogenated nitrile rubber film layer is 0.5 MPa - 35 MPa.

6. The diaphragm of the sound generating device according to claim 1, characterized in that, The loss factor of the modified hydrogenated nitrile rubber film layer at room temperature is >0.

12.

7. The diaphragm of the sound generating device according to claim 1, characterized in that, The additives include a cross-linking agent, a reinforcing agent and an anti-aging agent. Among them, the cross-linking agent is at least one of sulfur-based vulcanizing agents and peroxide-based vulcanizing agents; the reinforcing agent is at least one of carbon black, silica, calcium carbonate, barium sulfate, organic montmorillonite, unsaturated carboxylic acid metal salts, talc powder, clay, mica powder, feldspar powder, sulfates, magnetic powder and diatomaceous earth; the anti-aging agent is at least one of anti-aging agent N-445, anti-aging agent 246, anti-aging agent 4010, anti-aging agent SP, anti-aging agent RD, anti-aging agent ODA, anti-aging agent OD and anti-aging agent WH-02.

8. The diaphragm of the sound generating device according to claim 7, characterized in that, The content of the cross-linking agent accounts for 0.5 wt% - 5.5 wt% of the mixed rubber, the content of the reinforcing agent accounts for 5 wt% - 65 wt% of the mixed rubber, and the content of the anti-aging agent accounts for 0.1 wt% - 6.2 wt% of the mixed rubber.

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

10. The diaphragm of the sound generating device according to claim 1, characterized in that, The diaphragm is of a composite-layer structure, and the diaphragm further includes a film layer made of at least one of thermoplastic elastomers, engineering plastics and thermosetting elastomers.

11. A sound generating device, characterized in that, It includes a vibration system and a magnetic circuit system that cooperates with the vibration system. The vibration system includes a diaphragm and a voice coil combined on one side of the diaphragm. The magnetic circuit system drives the voice coil to vibrate to drive the diaphragm to emit sound, and the diaphragm is the diaphragm according to any one of claims 1-10.

12. A sound generating device, characterized in that, It includes a housing and a magnetic circuit system and a vibration system provided in the housing. 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 emit sound. Both ends of the second diaphragm are respectively connected to the housing and the bottom of the voice coil, and the second diaphragm is the diaphragm according to any one of claims 1-10.

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