CN116074704A

CN116074704A - Vibrating diaphragm of sound generating device and sound generating device

Info

Publication number: CN116074704A
Application number: CN202111275676.8A
Authority: CN
Inventors: 王翠翠; 惠冰; 李春; 凌风光; 刘春发; 张成飞
Original assignee: Goertek Inc
Current assignee: Goertek Inc
Priority date: 2021-10-29
Filing date: 2021-10-29
Publication date: 2023-05-05

Abstract

The application discloses sound generating apparatus's vibrating diaphragm and sound generating apparatus, the vibrating diaphragm includes at least one deck modified nitrile rubber rete, modified nitrile rubber rete is by inorganic hollow microsphere, additive and the polymer of acrylonitrile and butadiene monomer are mixed and are formed the compound and carry out the crosslinking reaction and prepare after the compound, and the diameter of inorganic hollow microsphere is 10 mu m ~ 100 mu m, and the distribution density of inorganic hollow microsphere in the modified nitrile rubber rete is 0.15g/cm ³ ～0.9g/cm ³ The specific surface area of the inorganic hollow microsphere is more than or equal to 0.9, and the loss factor of the modified nitrile rubber film layer at room temperature is more than 0.13. According to the method, the inorganic hollow microspheres are added into the polymer of the acrylonitrile and butadiene monomer, so that the density of the vibrating diaphragm can be effectively reduced. And byThe diameter of the inorganic hollow micro-beads and the distribution density of the inorganic hollow micro-beads in the modified nitrile rubber film layer are controlled, so that the specific surface area of the inorganic hollow micro-beads is more than or equal to 0.9, the bonding strength of the inorganic hollow micro-beads and the polymer can be improved, and the structural strength of the vibrating diaphragm can be improved.

Description

Vibrating diaphragm of sound generating device and sound generating device

Technical Field

The present application relates to the field of electroacoustic technologies, and more particularly, to a diaphragm of a sound generating device and a sound generating device using the diaphragm.

Background

Along with the rapid development of the 5G age, electroacoustic devices are gradually developed towards the directions of light weight, thinness, intellectualization, high power, high frequency and the like. Rubber vibrating diaphragms are often needed to be used in electroacoustic devices, and although the rubber vibrating diaphragms have good damping, compliance and fatigue resistance, the vibrating diaphragms are large in mass, the mass of a vibration system is increased, so that the sensitivity of a loudspeaker is reduced, the cost of the rubber vibrating diaphragms is high, and the production is not facilitated.

In addition, when the amplitude is relatively big, the intensity and the damping performance of the vibrating diaphragm of the existing rubber vibrating diaphragm are difficult to meet the use requirement at present, so that the sounding effect of the sounding device is influenced.

Disclosure of Invention

An object of the present application is to provide a diaphragm of a sound generating device.

Another object of the present application is to provide a sound generating apparatus comprising the above-mentioned diaphragm.

In order to achieve the above object, the present application provides the following technical solutions.

According to the vibrating diaphragm of the sound generating device of the embodiment of the first aspect of the application, the vibrating diaphragm comprises at least one layer of modified nitrile rubber film layer, the modified nitrile rubber film layer is prepared by mixing inorganic hollow microspheres, an additive and polymers of acrylonitrile and butadiene monomers to form a rubber compound and then carrying out a crosslinking reaction, wherein the diameter of the inorganic hollow microspheres is 10-100 mu m, and the distribution density of the inorganic hollow microspheres in the modified nitrile rubber film layer is 0.15g/cm ³ ～0.9g/cm ³ The specific surface area of the inorganic hollow microsphere is more than or equal to 0.9, and the modified nitrile rubber film layer is arranged in a roomThe loss factor at temperature is more than 0.13.

According to some embodiments of the present application, the modified nitrile rubber film layer has a tensile strength drop of 45% or less and an elongation at break drop of 70% or less after aging for 168 hours at 100 ℃ under hot air.

According to some embodiments of the present application, the tensile strength of the modified nitrile rubber film layer when broken is 2MPa to 45MPa.

According to some embodiments of the present application, the compressive strength of the inorganic hollow microsphere is not less than 10MPa.

According to some embodiments of the application, the content of the inorganic hollow microspheres accounts for 5-45 wt% of the total weight of the rubber compound.

According to some embodiments of the present application, the room temperature storage modulus of the modified nitrile rubber film layer is between 0.5MPa and 40MPa.

According to some embodiments of the present application, the tear strength of the modified nitrile rubber film layer is 15N/mm to 100N/mm.

According to some embodiments of the present application, the additive includes a cross-linking agent, a reinforcing agent, and an anti-aging agent, the cross-linking agent being at least one of a metal oxide, a metal peroxide, an organic oxide, and an organic peroxide system; the reinforcing agent is at least one of carbon black, white carbon black, graphene oxide, montmorillonite, talcum powder, clay, mica powder, feldspar powder, sodium alginate, magnetic powder and diatomite; the antioxidant is at least one of an antioxidant N-445, an antioxidant 246, an antioxidant 4010, an antioxidant SP, an antioxidant RD, an antioxidant ODA, an antioxidant OD and an antioxidant WH-02.

According to some embodiments of the present application, the cross-linking agent comprises 0.5wt% to 6wt% of the rubber compound, the reinforcing agent comprises 5wt% to 60wt% of the rubber compound, and the anti-aging agent comprises 0.1wt% to 5.7wt% of the rubber compound.

According to some embodiments of the present application, the modified nitrile rubber film layer has a density of 0.5g/cm ³ ～1.1g/cm ³ 。

According to some embodiments of the present application, the diaphragm is a single-layer structure, and the diaphragm is composed of one layer of the modified nitrile rubber film layer.

According to some 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.

According to the sound production device of the second aspect of the embodiment of the application, the sound production device comprises a vibration system and a magnetic circuit system matched with the vibration system, the vibration system comprises a vibrating diaphragm and a voice coil combined with one side of the vibrating diaphragm, the magnetic circuit system drives the voice coil to vibrate so as to drive the vibrating diaphragm to produce sound, and the vibrating diaphragm is the vibrating diaphragm according to the embodiment of the application.

According to the sound production device of the third aspect embodiment of the application, the sound production device comprises a shell, and a magnetic circuit system and a vibration system which are arranged in the shell, wherein the vibration system comprises a voice coil, a first vibrating diaphragm and a second vibrating diaphragm, the top of the voice coil is connected with the first vibrating diaphragm, the magnetic circuit system drives the voice coil to vibrate so as to drive the first vibrating diaphragm to produce sound, two ends of the second vibrating diaphragm are respectively connected with the shell and the bottom of the voice coil, and the second vibrating diaphragm is the vibrating diaphragm according to the embodiment of the application.

According to the vibrating diaphragm of the sound production device, after the inorganic hollow microspheres, the additive and the polymer of the acrylonitrile and butadiene monomer are mixed to form the mixed rubber, the modified nitrile rubber film layer prepared by the crosslinking reaction is a vibrating diaphragm material, so that the density of the modified nitrile rubber film layer is reduced, the weight of the vibrating diaphragm is reduced, and the sound production sensitivity of the vibrating diaphragm can be improved. In addition, by controlling the diameter of the inorganic hollow micro-beads and the distribution density of the inorganic hollow micro-beads in the modified nitrile rubber film layer, the specific surface area of the inorganic hollow micro-beads is more than or equal to 0.9, so that the bonding strength of the inorganic hollow micro-beads and the polymer can be improved, the structural strength of the vibrating diaphragm can be improved, and the tensile strength and damping performance of the vibrating diaphragm can be effectively improved.

Other features of the present application and its advantages will become apparent from the following detailed description of exemplary embodiments of the present application, which proceeds with reference to the accompanying drawings.

Drawings

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

FIG. 1 is a damping curve of inorganic hollow microsphere filled rubber with different diameters of a vibrating diaphragm of a sound generating device according to an embodiment of the present application after vulcanization;

FIG. 2 is a damping curve of a sound generating device with different added amounts of inorganic cenospheres filled with rubber after vulcanization according to an embodiment of the present application;

FIG. 3 is a graph showing harmonic distortion testing curves of a diaphragm of a sound generating device and a conventional diaphragm before and after high temperatures according to an embodiment of the present application;

FIG. 4 is a schematic diagram of the overall structure of a sound generating apparatus according to an embodiment of the present application;

FIG. 5 is a schematic view of a partial structure of a sound generating apparatus according to an embodiment of the present application;

FIG. 6 is a cross-sectional view of a sound emitting device according to an embodiment of the present application;

fig. 7 is an exploded view of a sound emitting device according to an embodiment of the present application.

Reference numerals

A sound generating device 100;

a housing 10; a voice coil 11; a first diaphragm 12; a second diaphragm 13; a magnetic circuit system 14;

a diaphragm 15; a folded ring portion 151; ball top 152.

Detailed Description

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

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

Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.

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

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.

The diaphragm of the sound generating device according to the embodiment of the application is specifically described below with reference to the accompanying drawings.

According to the vibrating diaphragm of the sound production device, the vibrating diaphragm comprises at least one layer of modified nitrile rubber film layer, the modified nitrile rubber film layer is prepared by mixing inorganic hollow microspheres, additives and polymers of acrylonitrile and butadiene monomers to form a rubber compound and then carrying out crosslinking reaction, wherein the diameter of the inorganic hollow microspheres is 10-100 mu m, and the distribution density of the inorganic hollow microspheres in the modified nitrile rubber film layer is 0.15g/cm ³ ～0.9g/cm ³ The specific surface area of the inorganic hollow microsphere is more than or equal to 0.9, and the loss factor of the modified nitrile rubber film layer at room temperature is more than 0.13.

The diaphragm of the sound generating device according to the embodiment of the application can be formed by at least one modified nitrile rubber film layer. Specifically, the diaphragm in the application may have a single-layer structure or a multi-layer composite structure. When the diaphragm is of a single-layer structure, i.e. the diaphragm is made of a modified nitrile rubber film layer according to the application. When the vibrating diaphragm is of a multilayer composite structure, the vibrating diaphragm comprises at least one layer of modified nitrile rubber film layer, and the modified nitrile rubber film layer in the vibrating diaphragm is compounded with film layers of other materials in the multilayer composite structure. Optionally, when the diaphragm contains multiple layers of modified nitrile rubber film layers, two adjacent layers of modified nitrile rubber film layers can be arranged at intervals or in a fitting manner, and can be selected according to actual use requirements, which is not particularly limited in the application. When the two adjacent modified nitrile rubber film layers are arranged at intervals, the film layers of other materials can be arranged between the two adjacent modified nitrile rubber film layers, and the two adjacent modified nitrile rubber film layers can be bonded.

The modified nitrile rubber film layer is prepared by mixing inorganic hollow microspheres, additives and polymers of acrylonitrile and butadiene monomers to form a mixed rubber and then carrying out crosslinking reaction. The polymer of acrylonitrile and butadiene monomers is a polymer synthesized from acrylonitrile and butadiene based monomers. The molecular formula of the polymer is shown as the following formula (I).

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In the formula (I), x, y and z are natural numbers.

Wherein the modified nitrile rubber film layer is prepared by adding inorganic hollow micro beads into nitrile rubber. Specifically, the inorganic hollow microspheres, the additive and the polymer of the acrylonitrile and butadiene monomer are mixed to form a mixed rubber, and the mixed rubber can be vulcanized to form a modified nitrile rubber film layer. That is, the polymers of acrylonitrile and butadiene monomers are capable of forming nitrile rubber, which corresponds to the substrate of the diaphragm material. After the inorganic hollow microspheres and the polymer of the acrylonitrile and butadiene monomer are mixed, the inorganic hollow microspheres can be uniformly dispersed in the base material. Because the density of the inorganic hollow micro-beads is smaller than that of the rubber, the density of the vibrating diaphragm material can be reduced by adding the inorganic hollow micro-beads into the rubber, and the vibrating diaphragm with low density can be obtained.

Further, the diameter of the inorganic hollow microspheres is 10 μm to 100. Mu.m, preferably 15 μm to 70. Mu.m. For example, the inorganic hollow microspheres may have a diameter of 10 μm, 15 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm. That is, the inorganic hollow microspheres with different diameters can be selected according to the thickness of the vibrating diaphragm, so as to ensure that the inorganic hollow microspheres are uniformly dispersed in the base material.

In addition, as the diameter of the inorganic hollow microsphere decreases,the distribution density of the inorganic hollow microspheres tends to increase, and the distribution density of the inorganic hollow microspheres can be controlled to be 0.15g/cm ³ ～0.9g/cm ³ Within the range, for example, the distribution density of the inorganic hollow microspheres may be 0.15g/cm ³ 、0.2g/cm ³ 、0.25g/cm ³ 、0.5g/cm ³ 、0.6g/cm ³ 、0.7g/cm ³ 、0.8g/cm ³ Or 0.9g/cm ³ . In order to ensure that the inorganic hollow microspheres can effectively reduce the density of the vibrating diaphragm, the distribution density of the inorganic hollow microspheres is preferably 0.25g/cm ³ ～0.8g/cm ³ 。

Further, the specific surface area of the inorganic hollow microsphere is more than or equal to 0.9, and the loss factor of the modified nitrile rubber film layer at room temperature is more than 0.13. As shown in fig. 1, different line shapes represent different inorganic hollow microsphere diameters, and as the diameter of the inorganic hollow microsphere decreases, the loss factor of the vulcanized rubber at room temperature increases. The specific surface area and the diameter are inversely proportional, namely, the specific surface area of the inorganic hollow microsphere with small diameter is large, and the specific surface area of the inorganic hollow microsphere with large diameter is small. Under the same technological conditions, the larger the contact area between the macromolecular chain and the small-diameter inorganic hollow microsphere is, the small-diameter inorganic hollow microsphere is tightly wrapped by rubber, the more the inorganic hollow microsphere is embedded into a rubber matrix, and the larger the chemical and physical binding points are, the larger the acting force between the inorganic hollow microsphere and the rubber is. When the external force is deformed, the more intense the friction between the inorganic hollow microsphere and the rubber matrix is, the larger the hysteresis loss generated under the dynamic strain is, and the larger the corresponding damping is.

In addition, the loss factor can be matched with the thickness of the vibrating diaphragm, and the performance of the vibrating diaphragm can be further optimized. Generally, the higher the loss factor is, the better the damping performance of the material is, the damping performance of the vibrating diaphragm material is improved, the polarization in the vibration process is reduced, the product distortion is reduced, and the listening yield is improved. For example, the loss factor may be 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, or 0.25, etc.

The smaller the diameter of the inorganic hollow microsphere, the larger the surface area of the inorganic hollow microsphere in unit mass, and the larger the reinforcing effect on rubber. However, the increase of the specific surface area greatly affects the processability of the unvulcanized rubber, so that the filling capacity of the unvulcanized rubber is reduced, the mixing time is increased, the dispersing ability is reduced, the roll-off property is increased, and the viscosity is increased. The inorganic hollow microsphere has larger diameter, small specific surface area and small bonding strength with rubber.

The diameter of the inorganic hollow microsphere selected by the method meets the processing performance of vulcanized rubber, the dispersion capacity is good, the roll stripping performance is good, the specific surface area is large, the inorganic hollow microsphere and the rubber are tightly combined, and the reinforcement is enhanced. Optionally, the inorganic hollow microsphere may be hollow microsphere composed of inorganic material such as hollow glass microsphere, ceramic glass microsphere, etc.

The table one shows the effect of inorganic hollow microspheres of the same addition and different diameters on the tensile strength of the rubber compound.

List one

Diameter of inorganic hollow microsphere (mum)	5	10	30	50	70
						Specific surface area (m) ² /g)	2.5	2.0	1.2	0.9	0.7
Tensile Strength (MPa)	12	10	7	4	3

From the first table, the larger the diameter of the hollow glass bead, the smaller the specific surface area of the hollow glass bead, and the lower the tensile strength of the modified nitrile rubber film layer. The inorganic hollow bead is selected as a hollow glass bead, and the hollow glass bead is one of the inorganic hollow beads, and the hollow glass bead or other inorganic hollow beads can also reflect the effect of the inorganic hollow bead in the material. That is, the smaller the diameter of the inorganic hollow microsphere, the better the reinforcement, the higher the tensile strength, the larger the diameter, the worse the reinforcement, the lower the stretching, the worse the stretching, and the membrane is easy to break in the high-power vibration process.

From this, according to the vibrating diaphragm of sound generating mechanism of this application embodiment, through adopting inorganic hollow microsphere, additive and acrylonitrile and butadiene monomer's polymer to mix after forming the elastomeric compound, the modified nitrile rubber rete that carries out the crosslinking reaction and prepare is the vibrating diaphragm material to make the density of modified nitrile rubber rete improved, the tensile strength and the reliability of the modified nitrile rubber rete of inorganic hollow microsphere have been added simultaneously effectively promoted.

According to one embodiment of the application, the compressive strength of the inorganic hollow microsphere is more than or equal to 10MPa.

That is, the inorganic hollow microsphere has higher compressive strength, not only can ensure that the inorganic hollow microsphere is not extruded and crushed in the mixing process, but also can effectively improve the tensile strength of the modified nitrile rubber film layer by adding the inorganic hollow microsphere into the polymer of the acrylonitrile and butadiene monomer. When the vibrating diaphragm has higher mechanical strength, the phenomenon that the vibrating diaphragm is excessively stretched due to overlarge driving force in a limiting environment can be avoided, and the using effect of the vibrating diaphragm is further guaranteed.

In some embodiments of the present application, the inorganic cenospheres comprise 5 to 45 weight percent of the total amount of the rubber compound.

That is, inorganic cenospheres may be added to the polymer of acrylonitrile and butadiene monomers in an amount of 5 to 45% by weight, preferably 10 to 40% by weight, based on the total amount of the rubber compound. Along with the increase of the addition amount of the inorganic hollow microspheres, the density of the modified nitrile rubber film layer is reduced, and the diaphragm material with the required performance can be obtained by controlling the addition amount of the inorganic hollow microspheres. The content of the inorganic hollow microsphere may be any value between 5wt% and 45wt%, for example, the content of the inorganic hollow microsphere may be 5wt%, 10wt%, 15wt%, 20wt%, 30wt%, 40wt% or 45wt%.

It should be noted that, because the density of the inorganic hollow microsphere is far smaller than that of the rubber, the density of the rubber material is obviously reduced with the increase of the adding mass of the inorganic hollow microsphere. In particular, when the content of the inorganic hollow microspheres is low (less than 5wt percent), the influence on the density of the vibrating diaphragm material is small, and the vibrating diaphragm still has a large density. When the content of the inorganic hollow microsphere is too high (more than 45wt percent), the maximum amplitude which can be achieved is reduced under the same driving force of the prepared vibrating diaphragm due to the too high mechanical strength, so that the low-frequency Fr of the generating device is reduced. In addition, the density of the modified nitrile rubber film layer can be greatly reduced by adding excessive inorganic hollow microspheres, and the prepared vibrating diaphragm has low elongation at break and strength and is easy to cause the reliability problems of collapse, film rupture and the like.

As shown in FIG. 2, the different linearities represent different contents of the inorganic hollow microspheres, and the loss factor of the modified nitrile rubber film layer is greatly improved along with the increase of the content of the inorganic hollow microspheres. Because the inorganic hollow micro-beads are wrapped by the rubber, a very thin polymer layer can be formed between the inorganic hollow micro-beads and the inorganic hollow micro-beads, and the interaction between the inorganic hollow micro-beads and the rubber makes the movement of the rubber chain segment in the polymer layer limited. With the increase of the consumption of the inorganic hollow micro-beads, the content of the high polymer layer with limited movement is continuously increased, so that the friction between the rubber and the inorganic hollow micro-beads and the friction between the inorganic hollow micro-beads and the inorganic hollow micro-beads are increased, the energy dissipation capacity of the system is improved, and the loss factor is increased.

When the consumption of the inorganic hollow micro-beads is continuously increased, the inorganic hollow micro-beads enter into the holes among the high polymer chain segments, so that the free volume of the inorganic hollow micro-beads and the rubber system is reduced, the relaxation movement of part of the molecular chain segments is limited, and the internal friction of the molecular chain movement is reduced, thereby reducing the loss factor. After the consumption of the inorganic hollow microspheres reaches a certain degree, the dispersibility in the rubber matrix is poor, the active points combined between the inorganic hollow microspheres and the rubber are reduced, so that the mass fraction of the combined rubber is smaller, the interface interaction is weakened, and the inorganic hollow microspheres form loose-structure aggregates in the rubber matrix, thereby affecting the dynamic mechanical properties of the rubber. Therefore, when the consumption of the inorganic hollow microspheres is large, the loss factor of the vulcanized rubber is reduced.

Watch II

Hollow glass bead addition (wt%)	0	5	10	40	50
						Elongation at break (%)	572	432	375	298	161

As shown in Table II, the elongation at break of the modified nitrile rubber film layer showed a decreasing trend with increasing amount of hollow glass beads. That is, as the amount of the inorganic hollow beads increases, the inorganic hollow beads are unevenly dispersed in the matrix, and the bonding force between the inorganic hollow beads and the rubber is relatively poor, so that the reinforcing effect is difficult to achieve. When made into a diaphragm, there is a risk of rupture of the diaphragm during long-term use.

The inorganic hollow bead is selected as a hollow glass bead, and the hollow glass bead is one of the inorganic hollow beads, and the hollow glass bead or other inorganic hollow beads can also reflect the effect of the inorganic hollow bead in the material. Therefore, the density and the strength of the vibrating diaphragm can be simultaneously considered by adopting the modified nitrile rubber film layer prepared by adding the inorganic hollow microspheres accounting for 5-45 wt% of the total amount of the rubber compound as the vibrating diaphragm material, after the rubber compound with the additive amount is vulcanized, the damping of the vibrating diaphragm is proper, the polarization of the vibrating diaphragm is inhibited, the sound quality is good, the distortion is low, the mechanical property is excellent, and the acoustic property and the reliability condition are met.

According to some embodiments of the present application, the density of the modified nitrile rubber film layer is 0.5g/cm ³ ～1.1g/cm ³ . For example, the density of the modified nitrile rubber film layer may be 0.5g/cm ³ 、0.6g/cm ³ 、0.7g/cm ³ 、0.8g/cm ³ 、0.9g/cm ³ 、1g/cm ³ Or 1.1g/cm ³ . Therefore, through the arrangement, the weight of the modified nitrile rubber film layer can be reduced by 30% -50%, and the sounding sensitivity of the vibrating diaphragm is greatly improved.

According to one embodiment of the application, after the modified nitrile rubber film layer is aged for 168 hours at 100 ℃, the tensile strength of the modified nitrile rubber film layer is reduced by less than or equal to 45 percent, and the elongation at break is reduced by less than or equal to 70 percent.

Specifically, the chemical component of the hollow glass microsphere is borosilicate, the borosilicate has higher temperature resistance, and when the borosilicate is added into NBR (nitrile butadiene rubber), a compact protective layer is formed on the surface of the rubber, so that the permeation of oxygen molecules is blocked, and the ageing resistance of a modified nitrile butadiene rubber film layer is effectively improved. Table three shows the influence of inorganic hollow micro beads with different contents on the tensile strength reduction rate and the elongation at break reduction rate of the modified nitrile rubber film after air aging for 168 hours at 100 ℃.

Watch III

Hollow glass bead addition (wt%)	0	5	10	40	50
						Percent decrease in tensile strength after aging (%)	51.7	45	41.4	32.6	30.5
Percent reduction in elongation at break (%)	75.6	69.7	67.1	42.1	32.6

As shown in Table III, when the mass fraction of the hollow glass beads was 0, the tensile strength after aging was 51.7% and the elongation at break was 75.6%. The inorganic hollow bead is selected as a hollow glass bead, and the hollow glass bead is one of the inorganic hollow beads, and the hollow glass bead or other inorganic hollow beads can also reflect the effect of the inorganic hollow bead in the material. That is, as the mass fraction of the inorganic hollow microspheres increases, the tensile strength of the modified nitrile rubber film layer gradually decreases after aging, and the elongation at break gradually decreases.

After the diaphragm and the conventional NBR rubber diaphragm in the embodiment of the application are both placed at 100 ℃ and stored for 168 hours, after the diaphragm and the conventional NBR rubber diaphragm are applied to a loudspeaker, the total harmonic distortion of the diaphragm is tested respectively, the test results are shown in fig. 3, and the loudspeaker diaphragm in the embodiment of the application has lower total harmonic distortion compared with the conventional NBR rubber diaphragm after the diaphragm is stored at 100 ℃ for 168 hours. This indicates that the vibrating diaphragm of this application embodiment still has excellent resilience after the high temperature storage, and the vibrating diaphragm is in the vibration process, and the vibration of swaying is few, and tone quality and listening stability are better.

In some embodiments of the present application, the tensile strength of the modified nitrile rubber film layer upon stretch-breaking is from 2MPa to 45MPa. That is, after forming a low-density rubber diaphragm material by adding inorganic cenospheres to a polymer of acrylonitrile and butadiene monomers, when the diaphragm material is broken, the tensile strength thereof can be controlled in the range of 2MPa to 45MPa. For example, the tensile strength of the modified nitrile rubber may be 2MPa, 6MPa, 10MPa, 16MPa, 20MPa, 25MPa, 30MPa, 40MPa, or 45MPa.

According to one embodiment of the present application, the tear strength of the modified nitrile rubber film layer is 15N/mm to 100N/mm. That is, when the diaphragm material is broken, the tear strength can be controlled in the range of 15N/mm to 100N/mm. The tear strength of the modified nitrile rubber may be 15N/mm, 30N/mm, 45N/mm, 50N/mm, 70N/mm, 90N/mm or 100N/mm. The modified nitrile rubber film layer has proper mechanical properties, and the diaphragm prepared from the modified nitrile rubber film layer is not easy to break in the use process of the sound production device, so that the use reliability of the diaphragm is effectively ensured.

That is, the low-density rubber diaphragm material is formed by adding the inorganic hollow microspheres into the base rubber, the room temperature storage modulus of the modified nitrile rubber film layer can be in the range of 0.5MPa to 40MPa, and the diaphragm can be ensured to have good rebound resilience.

The vibrating diaphragm prepared by using the modified nitrile rubber film layer as a raw material has excellent damping performance and rebound resilience, the vibration system can effectively inhibit polarization phenomenon in the vibration sounding process, the consistency of the vibration system is better, and the distortion of the sounding device is effectively reduced.

The higher the material strength and hardness, the higher the F0 of the diaphragm material, the lower the loudness of the speaker, and the lower the bass sound. Table four shows the values of the diaphragms F0 having the same thickness and different hardness.

Table four

Hardness (A)	29	35	60	75	80
						F0(Hz)	145	175	256	325	500

As can be seen from table four, as the hardness increases, F0 increases sharply.

It should be noted that the sound generating device may be a speaker. The loudspeaker comprises a vibration system and a magnetic circuit system matched with the vibration system, wherein the vibration system comprises a vibrating diaphragm provided by the application, and the vibrating diaphragm can be a folded ring vibrating diaphragm or a flat vibrating diaphragm. The loudspeaker with the vibrating diaphragm has the advantages of good sounding effect, good durability and the like.

In some embodiments of the present application, the hardness may be 35A-75A and the room temperature storage modulus may be 0.5 MPa-40 MPa, which enables the F0 of the speaker to reach 175 Hz-325 Hz, thereby achieving excellent low frequency performance of the speaker.

According to one embodiment of the present application, the additive includes a cross-linking agent, a reinforcing agent, and an anti-aging agent, the cross-linking agent being at least one of a metal oxide, a metal peroxide, an organic oxide, and an organic peroxide system. The reinforcing agent is at least one of carbon black, white carbon black, graphene oxide, montmorillonite, talcum powder, clay, mica powder, feldspar powder, sodium alginate, magnetic powder and diatomite. 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.

In some embodiments of the present application, the cross-linking agent comprises 0.5wt% to 6wt% of the mix, the reinforcing agent comprises 5wt% to 60wt% of the mix, and the anti-aging agent comprises 0.1wt% to 5.7wt% of the mix. For example, the crosslinker may be present in an amount of 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, or 6wt%. The content of the reinforcing agent may be 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt% or 60wt%. The content of the antioxidant may be 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt% or 5.7wt%

The content of the anti-aging agent is 0.1 to 5.7 percent of the rubber compound. In the use process of the rubber, the molecular chain breaks to generate free radicals with the extension of time, the self aging is accelerated, and the addition of the anti-aging agent stops the self-catalytic active free radicals generated in the rubber product. Too small an amount of addition does not achieve the effect of prolonging the service life, while too much amount of addition, because it cannot be well mutually dissolved with the elastomer, is difficult to uniformly disperse, leads to the decline of the mechanical properties of the material, and is easy to separate out to the surface along with the extension of time.

The content of the reinforcing agent is 5-60 wt% of the rubber compound, the reinforcing agent forms an interface with a rubber molecular chain through mutual interference, van der Waals force or hydrogen bond, when the material is stressed, the molecular chain slides on the surface of the reinforcing agent easily, but is not easy to separate from the reinforcing agent, the rubber molecule and the reinforcing agent form a strong bond capable of sliding, and the mechanical strength is increased. And the excessive reinforcing agent leads to remarkable increase of the tensile strength of the material, and the elongation at break is rapidly reduced, so that the product requirement cannot be met.

The content of the cross-linking agent is 0.5-6wt% of the rubber compound, the comprehensive performance of the rubber compound is optimal, the rubber compound has better processing performance, mechanical performance, oil resistance and thermal aging resistance, the glass transition temperature of the rubber film layer is less than or equal to-20 ℃, so that the loudspeaker diaphragm can keep better rubber elasticity all the time when working at the temperature lower than 0 ℃, and the loudspeaker shows higher tone quality. Meanwhile, the risk of damage to the loudspeaker diaphragm in a low-temperature environment is reduced, and the reliability is higher. And the lower glass transition temperature ensures that the modulus consistency of the material is high when the material works higher than the glass transition temperature, and the F0 of the diaphragm prepared from the diaphragm material has better stability in the whole temperature range. Table five shows the effect of the amount of vulcanizing agent added on the glass transition temperature and elongation at break of the modified nitrile rubber film layer.

TABLE five

Vulcanizing agent addition amount (wt%)	0.1	0.5	1	5	10
						Glass transition temperature (. Degree. C.)	-43	-32	-25	-20	-15.8
Elongation at break (%)	423	362	327	290	169

As can be seen from table five, as the vulcanizing agent increases, the glass transition temperature gradually increases and the elongation at break gradually decreases.

Therefore, when the total mass of the cross-linking agent is low, the effective cross-linking density of the material is low, the mechanical strength of the material is poor, the material is easy to deform in the process of preparing the diaphragm and long-term use, the vulcanization rate of the material is low, the production efficiency is severely limited, and the production cost is increased. Along with the increase of the dosage of the vulcanizing agent, the scorching time of the sizing material is shortened, the vulcanization speed is accelerated, the crosslinking density of the material is increased, the fatigue crack resistance of the vulcanized sizing material under the conditions of fixed extension stress, hardness, rebound resilience and fixed load is improved, the elongation at break is reduced, the permanent deformation and dynamic heat generation are reduced, the molecular chain movement is limited, and the glass transition temperature is increased. However, too high a crosslink density aggravates the non-uniformity of the crosslink distribution, resulting in non-uniformity of the stress distribution.

According to one embodiment of the application, the diaphragm is of a single-layer structure and is composed of a modified nitrile rubber film layer.

In some 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.

The thermoplastic elastomer is at least one selected from thermoplastic polyester elastomer, thermoplastic polyurethane elastomer, thermoplastic polyamide elastomer and organosilicon elastomer. The engineering plastic is at least one selected from polyether ether ketone, polyarylate, polyetherimide, polyimide, polyphenylene sulfide, polyethylene naphthalate, polyethylene terephthalate and polybutylene terephthalate. The thermosetting elastomer is at least one selected from the group consisting of Natural Rubber (NR), styrene-butadiene rubber (SBR), butadiene Rubber (BR), isoprene Rubber (IR), chloroprene Rubber (CR), butyl rubber (IIR), nitrile rubber (NBR), chlorinated nitrile rubber (HNBR), ethylene propylene rubber (EPDM), silicone rubber (Q), fluorosilicone rubber, fluororubber (FPM), polyurethane rubber (AU), acrylate rubber (ACM), ethylene-acrylate rubber (AEM), ethylene-vinyl acetate rubber (EVM), chlorosulfonated polyethylene rubber (CSM), epichlorohydrin rubber (CO) and polysulfide rubber.

In summary, according to the vibrating diaphragm of the sound generating device disclosed by the embodiment of the application, after the inorganic hollow microspheres, the additive and the polymer of the acrylonitrile and butadiene monomers are mixed to form the mixed rubber, the modified nitrile rubber film layer prepared by the crosslinking reaction is a vibrating diaphragm material, so that the damping performance of the modified nitrile rubber film layer is improved, meanwhile, the modulus change value of the modified nitrile rubber film layer added with the inorganic hollow microspheres is reduced in a high-temperature environment, so that the vibration frequency of the vibrating diaphragm can be reduced, the resonant frequency of the vibrating diaphragm is more stable, in addition, the density of the vibrating diaphragm is reduced by controlling the addition amount of the inorganic hollow microspheres, and the vibrating diaphragm has excellent ageing resistance and mucosa resistance, so that the medium-frequency performance and the service performance of the sound generating device are improved.

It should be noted that, the diaphragm provided in the present application may be formed into any sound generating device, for example, the following typical sound generating devices: the vibration system comprises a vibrating diaphragm and a voice coil combined on one side of the vibrating diaphragm. When the sounding device works, the voice coil can vibrate up and down under the action of the magnetic force of the magnetic circuit system after the voice coil is electrified so as to drive the vibrating diaphragm to vibrate, and sounding can be carried out when the vibrating diaphragm vibrates

According to the sound production device of the second aspect of the embodiment of the application, the sound production device comprises a vibration system and a magnetic circuit system matched with the vibration system, the vibration system comprises a vibrating diaphragm and a voice coil combined on one side of the vibrating diaphragm, the magnetic circuit system drives the voice coil to vibrate so as to drive the vibrating diaphragm to produce sound, and the vibrating diaphragm is the vibrating diaphragm of the embodiment.

As shown in fig. 4 and 5, the sound generating device includes a diaphragm 15 made by the embodiment of the present application, the diaphragm 15 may be composed of a folded ring portion 151 and a spherical top portion 152, and the modified nitrile rubber film layer may be applied to the folded ring portion 151 of the diaphragm. Those skilled in the art can make corresponding adjustment according to the actual product requirement, for example, the folded ring portion 151 protrudes toward the voice coil 11, the top portion 152 is located on the lower surface of the folded ring portion 151, and a centering support plate is added in the vibration system.

According to the sound generating device of the third aspect of the embodiment of the present application, as shown in fig. 6 and 7, the sound generating device comprises a housing 10, and a magnetic circuit system 14 and a vibration system which are arranged in the housing 10, wherein the vibration system comprises a voice coil 11, a first vibrating diaphragm 12 and a second vibrating diaphragm 13, the top of the voice coil 11 is connected with the first vibrating diaphragm 12, the magnetic circuit system 14 drives the voice coil 11 to vibrate so as to drive the first vibrating diaphragm 12 to generate sound, two ends of the second vibrating diaphragm 13 are respectively connected with the housing 10 and the bottom of the voice coil 11, and the second vibrating diaphragm 13 is a vibrating diaphragm of the above embodiment.

That is, the sound generating apparatus 100 according to the embodiment of the present application may further include two diaphragms prepared by the above embodiment of the present application, namely, the first diaphragm 12 and the second diaphragm 13, the first diaphragm 12 may be used for vibration sound generation, and the second diaphragm 13 may be used for balancing the vibration of the voice coil 11. Specifically, when the sound generating device 100 works, the voice coil 11 can vibrate up and down under the action of the magnetic field force of the magnetic circuit system 14 after the voice coil 11 is electrified to drive the first diaphragm 12 to vibrate, and sound can be generated when the first diaphragm 12 vibrates. The second vibrating diaphragm 13 can also vibrate up and down along with the voice coil 11, and as the two ends of the second vibrating diaphragm 13 are respectively connected with the bottom of the shell 10 and the bottom of the voice coil 11, the second vibrating diaphragm 13 can balance the vibration of the voice coil 11, and can prevent the voice coil 11 from generating polarization, thereby improving the sounding effect of the sounding device 100.

It should be noted that, the diaphragms of the embodiments described herein may be used for the first diaphragm 12 and the second diaphragm 13 at the same time, or one of the first diaphragm 12 and the second diaphragm 13 may be used for the diaphragms of the embodiments described herein, which is not particularly limited in this application.

The diaphragm of the sound generating device of the present application will be specifically described with reference to specific embodiments.

Example 1

The formula is as follows in parts by weight: 100 parts of nitrile rubber, 30 parts of carbon black, 4 parts of zinc oxide, 1.5 parts of stearic acid, 3 parts of accelerator, 1.8 parts of sulfur, 445 parts of anti-aging agent and 20 parts of hollow glass beads. Mixing according to the formula, and then carrying out crosslinking reaction to obtain the vibrating diaphragm material. Wherein the average diameter of the hollow glass beads is 25-35 mu m, and the density is 0.38g/cm ³ Specific surface area of 1.5m ² And/g, the compressive strength is 50MPa.

Comparative example one

The difference from example one is that no hollow glass microspheres were added. The other preparation steps of the diaphragm material are exactly the same as in example one.

Table six shows the results of performance tests of the diaphragm materials of comparative example one and example one, showing the effect of adding inorganic hollow microspheres on the tensile strength, elongation at break, swelling ratio and density of the diaphragm material.

Test conditions:

(1) Tensile properties tensile strength and elongation at break were determined according to ASTM D412-2016, the test specimens were dumbbell-shaped and had a tensile rate of 500mm/min, and each group of samples was tested 5 times to average;

(2) The room temperature loss factor is measured by dynamic mechanical test DMA, according to ASTM D5026-15 standard, stretching the clamp, measuring the temperature range to minus 50 ℃ to 200 ℃, heating up at a speed of 3 ℃/min, and taking an average value after each group of samples is tested for 3 times;

(3) The glass transition temperature test is in accordance with ISO6721-4, the temperature rising rate is 20 ℃/min.

Each group of samples was tested 3 times to average;

(4) Specific surface area the specific surface area of the sample was calculated by BET method using a specific surface area meter test by Bei Shide company.

TABLE six

/	Specific gravity g/cm ³	Loss factor	Tensile strength MPa	Elongation at break%
					Example 1	1.0	0.23	10	350
Comparative example one	1.3	0.12	12	435

As can be seen from table six, the first embodiment has a lower density than the first comparative embodiment and is lighter in weight, thereby improving the sound sensitivity of the diaphragm. And the specific surface area of the hollow glass beads is 1.5m ² And/g, the structural strength of the vibrating diaphragm is enhanced, the loss factor and the tensile strength of the vibrating diaphragm are improved, the friction between the rubber and the hollow glass beads is increased, and the energy dissipation capacity of the system is improved.

That is, the vibration film manufactured by the embodiment of the application has reduced distortion, the inorganic hollow micro beads are used as hollow materials, and when the rubber materials are stretched, the cross-sectional area of the materials is reduced, the strength of the materials is greatly affected, the reduction degree is within 20%, the vibration film material requirement is completely met, and the use effect of the vibration film and the acoustic performance of the sound generating device are ensured.

Although specific embodiments of the present application have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present application. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present application. The scope of the application is defined by the appended claims.

Claims

1. The vibrating diaphragm of the sound production device is characterized by comprising at least one layer of modified nitrile rubber film layer, wherein the modified nitrile rubber film layer is prepared by mixing inorganic hollow microspheres, additives and polymers of acrylonitrile and butadiene monomers to form a rubber compound and then carrying out crosslinking reaction;

wherein the diameter of the inorganic hollow microsphere is 10-100 mu m, and the distribution density of the inorganic hollow microsphere in the modified nitrile rubber film layer is 0.15g/cm ³ ～0.9g/cm ³ The specific surface area of the inorganic hollow microsphere is more than or equal to 0.9, and the loss factor of the modified nitrile rubber film layer at room temperature is more than 0.13.

2. The sound emitting device diaphragm of claim 1, wherein the modified nitrile rubber film layer has a tensile strength drop of 45% or less and an elongation at break drop of 70% or less after aging for 168 hours at 100 ℃ under hot air.

3. The diaphragm of the sound generating apparatus according to claim 1, wherein the tensile strength of the modified nitrile rubber film layer when broken is 2MPa to 45MPa.

4. The diaphragm of the sound generating apparatus according to claim 1, wherein the compressive strength of the inorganic hollow microsphere is not less than 10MPa.

5. The diaphragm of the sound generating device according to claim 1, wherein the content of the inorganic hollow microspheres is 5-45 wt% of the total amount of the rubber compound.

6. The diaphragm of the sound generating apparatus according to claim 1, wherein the room temperature storage modulus of the modified nitrile rubber film layer is 0.5MPa to 40MPa.

7. The diaphragm of the sound generating apparatus of claim 1, wherein the modified nitrile rubber film layer has a tear strength of 15N/mm to 100N/mm.

8. The diaphragm of the sound generating apparatus of claim 1, wherein the additive comprises a cross-linking agent, a reinforcing agent, and an anti-aging agent, the cross-linking agent being at least one of a metal oxide, a metal peroxide, an organic oxide, and an organic peroxide system; the reinforcing agent is at least one of carbon black, white carbon black, graphene oxide, montmorillonite, talcum powder, clay, mica powder, feldspar powder, sodium alginate, magnetic powder and diatomite; the antioxidant is at least one of an antioxidant N-445, an antioxidant 246, an antioxidant 4010, an antioxidant SP, an antioxidant RD, an antioxidant ODA, an antioxidant OD and an antioxidant WH-02.

9. The sound emitting device diaphragm of claim 8, wherein the cross-linking agent is present in an amount of 0.5wt% to 6wt% of the rubber compound, the reinforcing agent is present in an amount of 5wt% to 60wt% of the rubber compound, and the anti-aging agent is present in an amount of 0.1wt% to 5.7wt% of the rubber compound.

10. The sound emitting device diaphragm of claim 1, wherein the modified nitrile rubber layer has a density of 0.5g/cm ³ ～1.1g/cm ³ 。

11. The diaphragm of the sound generating apparatus according to claim 1, wherein the diaphragm has a single-layer structure, and the diaphragm is composed of one layer of the modified nitrile rubber film layer.

12. The sound generating apparatus diaphragm of claim 1, wherein the diaphragm is a composite layer structure, and the diaphragm further comprises a film layer made of at least one of a thermoplastic elastomer, an engineering plastic, and a thermosetting elastomer.

13. The utility model provides a sound generating device, its characterized in that includes vibration system and with vibration system matched with magnetic circuit system, vibration system includes the vibrating diaphragm and combines the voice coil loudspeaker voice coil in vibrating diaphragm one side, magnetic circuit system drives the voice coil loudspeaker voice coil vibrates in order to drive the vibrating diaphragm sound production, the vibrating diaphragm is the vibrating diaphragm of any one of claims 1-12.

14. The utility model provides a sound generating device, its characterized in that includes the casing and establishes magnetic circuit and vibration system in the casing, vibration system includes voice coil loudspeaker voice coil, first vibrating diaphragm and second vibrating diaphragm, the top of voice coil loudspeaker voice coil with first vibrating diaphragm links to each other, magnetic circuit drives the voice coil loudspeaker voice coil vibrates in order to drive first vibrating diaphragm sound production, the both ends of second vibrating diaphragm respectively with the casing with the bottom of voice coil loudspeaker voice coil links to each other, the second vibrating diaphragm is the vibrating diaphragm of any one of claims 1-12.