CN110708639A - Vibrating diaphragm for miniature sound generating device and miniature sound generating device - Google Patents

Vibrating diaphragm for miniature sound generating device and miniature sound generating device Download PDF

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Publication number
CN110708639A
CN110708639A CN201911055461.8A CN201911055461A CN110708639A CN 110708639 A CN110708639 A CN 110708639A CN 201911055461 A CN201911055461 A CN 201911055461A CN 110708639 A CN110708639 A CN 110708639A
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diaphragm
chloroprene rubber
content
plasticizer
agent
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CN110708639B (en
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彭威锋
凌风光
李春
刘春发
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Goertek Inc
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Goertek Inc
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Priority to PCT/CN2019/128166 priority patent/WO2021082248A1/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/12—Non-planar diaphragms or cones
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/02—Details
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/06—Loudspeakers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2207/00—Details of diaphragms or cones for electromechanical transducers or their suspension covered by H04R7/00 but not provided for in H04R7/00 or in H04R2307/00
    • H04R2207/021—Diaphragm extensions, not necessarily integrally formed, e.g. skirts, rims, flanges
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2400/00—Loudspeakers
    • H04R2400/11—Aspects regarding the frame of loudspeaker transducers

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
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  • Compositions Of Macromolecular Compounds (AREA)

Abstract

The invention discloses a vibrating diaphragm for a miniature sound generating device and the miniature sound generating device. The diaphragm comprises at least one elastic body layer, wherein the elastic body layer is made of chloroprene rubber; the molecular chain structure of the chloroprene rubber comprises an isomer of chlorinated butadiene; the molecular weight of the chloroprene rubber is 10000-500000. The vibrating diaphragm provided by the invention has excellent elasticity and fatigue resistance.

Description

Vibrating diaphragm for miniature sound generating device and miniature sound generating device
Technical Field
The invention relates to the technical field of acoustic devices, in particular to a vibrating diaphragm for a miniature sound generating device and the miniature sound generating device.
Background
In recent years, with the rapid development of small electronic devices such as mobile phones and tablet computers, a miniature sound generating device with smaller size and better performance is required to be arranged in the electronic devices. The diaphragm is one of the most important parts in the miniature sound-generating device.
The existing diaphragm for the miniature sound production device is mostly made of high-modulus engineering plastic materials, such as PEEK, PAR, PEI, PI and the like. Although the engineering plastic materials have good temperature resistance, the materials have poor resilience, and the products are easy to generate membrane folding and cannot play a waterproof role. Particularly, the diaphragm made of the engineering plastic materials has poor fatigue resistance and rebound resilience, cannot keep excellent elasticity all the time in the long-term vibration process, and is easy to cause poor listening, so that the acoustic performance of the sound production device is poor. In addition, the conventional diaphragm cannot be normally used under extreme conditions, and has many defects.
Therefore, a new technical solution is needed to solve the above technical problems.
Disclosure of Invention
The invention aims to provide a vibrating diaphragm for a miniature sound generating device and a novel technical scheme of the miniature sound generating device.
According to one aspect of the present invention, there is provided a diaphragm for a miniature sound generating apparatus, the diaphragm comprising at least one elastomer layer, wherein the elastomer layer is made of neoprene;
the molecular chain structure of the chloroprene rubber comprises an isomer of chlorinated butadiene;
the molecular weight of the chloroprene rubber is 10000-500000.
Optionally, the isomers of chlorinated butadiene include the following components:
trans-1, 4-structure with a content of 70-95%;
cis-1, 4-structure, content is 2% -25%;
1, 2 structure, the content is 0.1% -5%; and
3, 4, the content is 0.1-5%;
wherein, the molecular structural formula of the trans-1, 4-structure is as follows:
Figure BDA0002256434310000021
the molecular structural formula of the cis-1, 4-structure is as follows:
the molecular structural formula of the 1, 2 structure is as follows:
Figure BDA0002256434310000023
the molecular structural formula of the 3, 4 structure is as follows:
optionally, the chloroprene rubber is mixed with an inorganic filler reinforcing agent, the inorganic filler reinforcing agent is at least one of carbon black, white carbon black, nano titanium dioxide, talcum powder, precipitated calcium carbonate and barium sulfate, and the content of the inorganic filler reinforcing agent is 15% -90% of the total amount of the chloroprene rubber.
Optionally, the content of the inorganic filler reinforcing agent is 30-70% of the total amount of the chloroprene rubber.
Optionally, the chloroprene rubber is mixed with an anti-aging agent, 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, and the content of the anti-aging agent is 0.5-10% of the total amount of the chloroprene rubber.
Optionally, the content of the anti-aging agent is 1% -5% of the total amount of the chloroprene rubber.
Optionally, the chloroprene rubber is mixed with a plasticizer, the plasticizer is at least one of an aliphatic dibasic acid ester plasticizer, a phthalate plasticizer, a benzene polyacid ester plasticizer, a benzoate plasticizer, a polyol ester plasticizer, a chlorinated hydrocarbon plasticizer, an epoxy plasticizer, a citrate plasticizer and a polyester plasticizer, and the content of the plasticizer is 1% -10% of the total amount of the chloroprene rubber.
Optionally, the plasticizer is present in an amount of 3% to 7% of the total amount of the neoprene.
Optionally, the chloroprene rubber is mixed with an internal release agent, the internal release agent adopts at least one of stearic acid, stearate, octadecyl amine, alkyl phosphate and alpha-octadecyl-omega-hydroxy polyoxyethylene phosphate, and the content of the internal release agent is 0.5-5% of the total amount of the chloroprene rubber.
Optionally, the content of the internal mold release agent is 1% -3% of the total amount of the chloroprene rubber.
Optionally, vulcanizing agents are mixed in the chloroprene rubber, and the vulcanizing agents comprise a metal oxide system vulcanizing agent and a thiourea vulcanizing agent.
Optionally, the metal oxide system vulcanizing agent adopts magnesium oxide, zinc oxide or calcium oxide, and the content of the metal oxide system vulcanizing agent is 2% -10% of the total amount of the chloroprene rubber;
the content of the thiourea vulcanizing agent is 0.5 to 5 percent of the total amount of the chloroprene rubber.
Optionally, the diaphragm is a single-layer diaphragm, and the single-layer diaphragm is formed by a layer of chloroprene rubber film; in the alternative, the first and second sets of the first,
the vibrating diaphragm is a composite vibrating diaphragm, the composite vibrating diaphragm comprises two layers, three layers, four layers or five layers of film layers, and the composite vibrating diaphragm at least comprises one layer of chloroprene rubber film layer.
Optionally, the thickness of the neoprene film layer is 10 μm to 200 μm.
Optionally, the thickness of the neoprene film layer is 30 μm to 120 μm.
Optionally, the neoprene has a hardness in the range of 30-95A.
Optionally, the neoprene has a glass transition temperature in the range of-50 to 0 ℃.
Optionally, the neoprene has a loss factor greater than 0.06 at room temperature.
Optionally, the neoprene has an elongation at break greater than 100%.
According to another aspect of the present invention, a miniature sound generating apparatus is provided. This miniature sound generating mechanism includes sound generating mechanism main part and foretell vibrating diaphragm, the vibrating diaphragm sets up in the sound generating mechanism main part, the vibrating diaphragm is configured to can vibrate the sound production.
The inventor of the present invention finds that, in the prior art, the rebound resilience and fatigue resistance of the diaphragm are poor, which affects the acoustic performance of the sound generating device. Therefore, the technical task to be achieved or the technical problems to be solved by the present invention are never thought or anticipated by those skilled in the art, and therefore the present invention is a new technical solution.
The invention has the beneficial effects that: the invention discloses a vibrating diaphragm made of a chloroprene rubber material, which has better fatigue resistance and elasticity, can work for a long time under extreme conditions, and can keep good rebound resilience and reliability. Thus, the sound-emitting device can be applied to extremely severe environments while the acoustic performance thereof is kept in good condition.
Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, 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 invention and together with the description, serve to explain the principles of the invention.
Fig. 1 is a comparison graph of total harmonic distortion test curves of the diaphragm provided by the invention and the conventional diaphragm.
Fig. 2 is a test curve of vibration displacement of different parts of a diaphragm of a sound generating device under different frequencies according to an embodiment of the present invention.
Fig. 3 is a test curve of vibration displacement of different parts of a conventional diaphragm under different frequencies.
Fig. 4 is a graph of the impedance of diaphragms of different stiffness.
Fig. 5 is a comparison graph of the loudness of the diaphragm provided by the present invention and the conventional diaphragm at different frequencies.
Detailed Description
Various exemplary embodiments of the present invention 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, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.
The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.
Techniques, methods, and apparatus known to those 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 particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
According to one embodiment of the present invention, a diaphragm of a sound generating apparatus is provided. The vibrating diaphragm comprises at least one elastic body layer, and the elastic body layer is made of chloroprene rubber. The diaphragm can be applied to a sound generating device such as a loudspeaker, and particularly can be applied to a miniature sound generating device.
The molecular weight of the chloroprene rubber is relatively large and can reach 10000-500000.
The molecular chain structure of the chloroprene rubber comprises isomers of chlorinated butadiene with different contents. Specifically, the isomers of chlorinated butadiene specifically include:
trans-1, 4-structure with a content of 70-95%;
cis-1, 4-structure, content is 2% -25%;
1, 2 structure, the content is 0.1% -5%; and
3, 4 structure, the content is 0.1-5%.
The molecular structural formula of the trans-1, 4-structure is as follows:
the molecular structural formula of the cis-1, 4-structure is as follows:
Figure BDA0002256434310000052
the molecular structural formula of the 1, 2 structure is as follows:
Figure BDA0002256434310000061
the molecular structural formula of the 3, 4 structure is as follows:
Figure BDA0002256434310000062
in particular, neoprene has a unique molecular structure and is called specialty rubber. The molecular structure of the chloroprene rubber is mostly composed of alpha-polymers with linear structures, the molecular chain structure is regular, and chlorine atom polar groups are arranged on the molecular chain, so that the acting force among molecules can be increased. Therefore, under the action of external force, the chloroprene rubber is easy to stretch and crystallize, so that the molecules are not easy to slip. In addition, the molecular weight of the chloroprene rubber is also larger and can reach 10000-500000, and the molecular weight distribution is also more uniform, so that the chloroprene rubber has high physical and mechanical strength and performance which is not greatly different from that of natural rubber, and is better than styrene butadiene rubber and nitrile butadiene rubber.
Due to the existence of polar chlorine atoms in the molecule of the chloroprene rubber, the chloroprene rubber releases hydrogen chloride gas with fire extinguishing effect at high temperature. Therefore, chloroprene rubber also has excellent flame retardant properties compared to other rubbers. In addition, chlorine atoms on the molecular chain of the chloroprene rubber protect carbon-carbon double bonds, so that the chloroprene rubber has good stability.
The chlorine atoms also impart a significant polarity to the neoprene. Thus, neoprene is a highly polymeric and cohesive polar rubber. Because the surface of the bonded material is polar, the chloroprene rubber has good affinity with the adhesive, so that the vibrating diaphragm made of the chloroprene rubber has higher reliability during bonding and molding.
The vibrating diaphragm provided by the invention is made of chloroprene rubber materials, so that the vibrating diaphragm has high elasticity and excellent fatigue resistance. Moreover, the rubber can work for a long time under extreme conditions, and good rebound resilience and reliability can be maintained. Thus, the sound-emitting device can be applied to extremely severe environments while the acoustic performance thereof is kept in good condition.
Optionally, an inorganic filler reinforcing agent may be mixed in the chloroprene rubber. The inorganic filler reinforcing agent comprises at least one of carbon black, white carbon black, nano titanium dioxide, talcum powder, precipitated calcium carbonate and barium sulfate. And under the condition that the mass fraction of the chloroprene rubber per se is 100 parts, the mass fraction of the inorganic filler reinforcing agent per se is 15-90 parts, namely the content of the inorganic filler reinforcing agent is 15-90% of the total amount of the chloroprene rubber.
The surface of the inorganic filler reinforcing agent has a group such as hydrogen, carboxyl, lactone, radical, quinone, etc. capable of undergoing substitution, reduction, oxidation, etc. After the inorganic filler reinforcing agent is mixed into the chloroprene rubber, due to the strong interaction between the molecular interface of the inorganic filler reinforcing agent and the chloroprene rubber, when the material is stressed, molecular chains can slide on the surfaces of the inorganic filler reinforcing agent particles relatively easily, but are not easy to be separated from the inorganic filler reinforcing agent particles, the chloroprene rubber and the inorganic filler reinforcing agent particles form a strong slidable bond, and the mechanical strength is increased. In addition, the particle size of the inorganic filler reinforcing agent, the structure of the filler and the surface activity of the filler are the primary factors for examining the rubber filler. The three major factors are generally depended on each other, and the smaller the particle size of the inorganic filler reinforcing agent is, the larger the specific surface area of the corresponding inorganic filler reinforcing agent is; the larger the specific surface area of the inorganic filler reinforcing agent, the stronger the corresponding surface activity.
Taking carbon black as an example, the carbon black mainly comprises carbon elements, the proportion of which reaches 95% -99%, and belongs to the graphite crystal type. Carbon black is an amorphous structure, and particles form aggregates by physicochemical bonding to each other. The primary structure of the carbon black is composed of aggregates, and van der waals force or hydrogen bonds exist among the aggregates, so that the aggregates can be aggregated into a spatial network structure, namely the secondary structure of the carbon black. The surface of the carbon black is provided with groups such as hydrogen, carboxyl, lactone group, free radical, quinone group and the like which can generate substitution, reduction, oxidation reaction and the like, when the carbon black is added into the chloroprene rubber, molecular chains can slide on the surface of the carbon black easily but are not easy to separate from the carbon black due to strong interaction between the surface of the carbon black and a molecular interface of the chloroprene rubber when the material is stressed, and the chloroprene rubber and the carbon black form a strong slidable bond, so that the mechanical strength of the chloroprene rubber is increased.
Taking the example of selecting carbon black as the inorganic filler reinforcing agent, when the mass portion of the carbon black is 10, the mechanical strength and the elongation at break of the chloroprene rubber material are both relatively small, because the amount of the carbon black is small, the carbon black is unevenly dispersed in the matrix, and the reinforcing effect is difficult to achieve. The mechanical strength of the chloroprene rubber material can be increased and the elongation at break can be gradually reduced with the increase of the addition amount of the carbon black.
In an embodiment, when the mass fraction of the chloroprene rubber is 100, preferably, the mass fraction of the inorganic filler reinforcing agent is 30 to 70 parts, that is, the content of the inorganic filler reinforcing agent is 30 to 70% of the total amount of the chloroprene rubber, the requirements of the invention on the diaphragm performance can be better satisfied. Of course, those skilled in the art can flexibly adjust the method according to specific needs, and the method is not limited thereto.
Optionally, an antioxidant may be mixed in the chloroprene rubber. The antioxidant may be at least one of antioxidant N-445, antioxidant 246, antioxidant 4010, antioxidant SP, antioxidant RD, antioxidant ODA, antioxidant OD and antioxidant WH-02, for example. And when the mass fraction of the chloroprene rubber per se is 100 parts, the mass fraction of the anti-aging agent per se is 0.5-10 parts, namely the content of the anti-aging agent is 0.5-10% of the total amount of the chloroprene rubber.
In the using process of the chloroprene rubber, as the chloroprene rubber is influenced by factors such as oxygen, ultraviolet lamps and the like for a long time along with the use time, molecular chains of the chloroprene rubber are gradually broken to generate free radicals, and the self aging is accelerated, which is the natural aging phenomenon of the chloroprene rubber. In the present invention, the incorporation of an antioxidant into the chloroprene rubber can prevent, stop or slow down the generation of autocatalytically active radicals in the chloroprene rubber. If the amount of the antioxidant is too small, the effect of extending the life of the chloroprene rubber may not be obtained. On the other hand, if the amount of the antioxidant is too large, the antioxidant is difficult to be dissolved in the chloroprene rubber sufficiently and is difficult to be dispersed uniformly, which may result in deterioration of mechanical properties of the chloroprene rubber. Therefore, when the mass part of the chloroprene rubber is 100 parts, the mass part of the antioxidant itself may be selected in the range of 0.5 to 10 parts. Preferably, the mass part of the anti-aging agent is 1-5 parts, namely the content of the anti-aging agent is 1-5% of the total amount of the chloroprene rubber. Of course, those skilled in the art can flexibly adjust the method according to specific needs, and the method is not limited thereto.
Optionally, a plasticizer may be mixed into the chloroprene rubber. The plasticizer is at least one of aliphatic dibasic acid ester plasticizer, phthalate plasticizer (including phthalate and terephthalate, for example), benzene polyacid ester plasticizer, benzoate plasticizer, polyol ester plasticizer, chlorinated hydrocarbon plasticizer, epoxy plasticizer, citric acid ester plasticizer and polyester plasticizer.
The molecule of the plasticizer is much smaller than that of the chloroprene rubber molecule chain, so that the plasticizer molecule can move in the chloroprene rubber molecule after being added, namely, the space required by chain segment movement can be conveniently provided, the glass transition temperature of the material is reduced, the cold resistance of the material is increased, and the processing performance of the material is improved. However, an excessive amount of plasticizer precipitates from the inside of the material, and the mechanical properties of the material are rather degraded.
In an embodiment, in the case that the mass part of the chloroprene rubber is 100 parts, optionally, the mass part of the plasticizer is 1 to 10 parts, that is, the content of the plasticizer is 1 to 10% of the total amount of the chloroprene rubber. In fact, as the amount of plasticizer used increases, the glass transition temperature of the neoprene material decreases, but the tensile strength of the neoprene material decreases accordingly. In addition, an excessive amount of plasticizer is also precipitated from the interior of the chloroprene rubber material, and the mechanical properties of the chloroprene rubber material are degraded. When the mass portion of the plasticizer per se meets the range, the performance of the chloroprene rubber can meet the performance requirement of the vibrating diaphragm. Preferably, the mass part of the plasticizer is 3-7 parts, namely, the content of the plasticizer is 3% -7% of the total amount of the chloroprene rubber. Of course, those skilled in the art can flexibly adjust the method according to specific needs, and the method is not limited thereto.
Optionally, an internal mold release agent may be mixed into the neoprene. The internal mold release agent adopts at least one of stearic acid, stearate, octadecyl amine, alkyl phosphate and alpha-octadecyl-omega-hydroxyl polyoxyethylene phosphate. Technical problems of roller sticking, mold sticking and the like can possibly occur in the injection molding processing process of the chloroprene rubber. The invention improves the processing performance of the chloroprene rubber by adding the internal release agent into the rubber material of the chloroprene rubber.
The releasing ability of the chloroprene rubber is correlated with the mixing amount of the internal mold release agent. Specifically, the method comprises the following steps: if the amount of the internal mold release agent is small, the molding state of the chloroprene rubber is good, but the releasing ability is poor, and it is difficult to improve the problem of the sticking film. If the amount of the internal mold release agent is too large, the releasing performance of the chloroprene rubber is remarkably improved, but the formed chloroprene rubber is liable to have a problem that the internal mold release agent is precipitated, deposited on the surface of a mold, and contaminates the mold. In an embodiment of the present invention, when the mass part of the chloroprene rubber is 100 parts, the mass part of the internal mold release agent itself may be selected to be 0.5 to 5 parts, that is, the content of the internal mold release agent is 0.5 to 5% of the total amount of the chloroprene rubber. Preferably, the mass part of the internal release agent is 1-3 parts, namely the content of the internal release agent is 1-3% of the total weight of the chloroprene rubber, and the formed chloroprene rubber has good forming state and little residue after forming. Of course, those skilled in the art can flexibly adjust the method according to specific needs, and the method is not limited thereto.
Optionally, a vulcanizing agent may be mixed in the chloroprene rubber. The vulcanizing agent comprises a metal oxide system vulcanizing agent and a thiourea vulcanizing agent.
The metal oxide system vulcanizing agent can adopt magnesium oxide, zinc oxide or calcium oxide. And the content of the metal oxide system vulcanizing agent is 2-10% of the total amount of the chloroprene rubber. In addition to the mixing of the metal oxide system vulcanizing agent with the chloroprene rubber, a thiourea-based vulcanizing agent is mixed in a predetermined amount. The content of the thiourea vulcanizing agent is 0.5 to 5 percent of the total amount of the chloroprene rubber.
Optionally, the glass transition temperature of the diaphragm is in a range of-50 ℃ to 0 ℃. The chloroprene rubber has higher molecular weight, and molecular chains of the chloroprene rubber are more flexible, so that the chloroprene rubber has better low-temperature resistance. When the vibrating diaphragm meets the range of the glass transition temperature, the vibrating diaphragm of the sound generating device can keep a high elastic state at normal temperature, and the rebound resilience is good. Within a certain range, the lower the glass transition temperature is, the lower the temperature at which the diaphragm can normally operate. The lower the glass transition temperature, the lower the resonant frequency F0 of the assembled sound generating device, with the thickness of the diaphragm unchanged.
In one embodiment, the invention provides a diaphragm having a glass transition temperature in the range of-50 ℃ to 0 ℃, preferably-30 ℃ to 0 ℃. The vibrating diaphragm can keep a high elastic state at normal temperature and has good rebound resilience. More importantly, even when the temperature is lower than 0 ℃, the diaphragm can still keep better rubber elasticity when working, so that the sound production device can show higher sound quality. Meanwhile, the risk of damage of the vibrating diaphragm in a low-temperature environment is reduced, and the reliability is higher.
The molecular chain of the chloroprene rubber is softer, so that the chloroprene rubber has excellent toughness. The diaphragm made of chloroprene rubber has an elongation at break greater than 100%. Preferably, the elongation at break of the diaphragm is greater than 150%. The vibrating diaphragm provided by the invention has higher elongation at break, so that the vibrating diaphragm is not easy to have the reliability problems of film breaking and the like when being used in a sound generating device.
Under the same stress, the strain of the diaphragm provided by the embodiment of the invention is obviously larger than that of the PEEK diaphragm in the prior art. This indicates that: the Young modulus of the diaphragm provided by the embodiment of the invention is obviously smaller than that of a PEEK diaphragm in the prior art.
In addition, the PEEK diaphragms of the prior art form a significant yield point, on the order of 0.4-0.5% strain. The loudspeaker diaphragm provided by the invention has no yield point. This indicates that: the diaphragm provided by the invention has a wider elastic area and excellent resilience.
The diaphragm made of the chloroprene rubber material has good flexibility. For example, the elongation at break is 100% or more. Among them, the molecular chain of chloroprene rubber has very important influence on the elongation at break, and those skilled in the art can select according to the actual needs. This makes the vibration displacement of sound generating mechanism vibrating diaphragm bigger, and the loudness is bigger. And has good reliability and durability. The better the flexibility of the chloroprene rubber material, the greater the elongation at break, the stronger the ability of the diaphragm to resist damage. When the vibrating diaphragm vibrates in a large-amplitude state, the chloroprene rubber material generates large strain, and the risk of membrane folding, membrane cracking or membrane breaking can occur during long-time vibration. The vibrating diaphragm of the invention which takes the chloroprene rubber as the base material has good flexibility, and the risk of the vibrating diaphragm damage is reduced. The higher the elongation at break, the lower the membrane rupture rate of the diaphragm in long-term use.
Compared with engineering plastics, the chloroprene rubber provided by the invention has a wider elastic area, and when the strain of the diaphragm occurs in the area, the diaphragm has excellent resilience after an external force is removed. Correspondingly, the vibrating diaphragm has less swing vibration and better tone quality and listening stability in the vibration process.
As shown in fig. 1, the diaphragm provided by the present invention has a lower THD (total harmonic distortion) than the PEEK diaphragm of the prior art. This indicates that: the diaphragm provided by the invention has more excellent anti-polarization capability and better tone quality.
The vibrating diaphragm provided by the invention is in a high-elastic state at room temperature, the molecular chain is easy to move, the intermolecular friction is large, and the vibrating diaphragm has better damping performance. Optionally, the loss factor of the diaphragm is greater than 0.06 at room temperature. The diaphragm has excellent damping performance and can have lower impedance. The damping of the vibrating diaphragm is improved, the ability of a vibration system of the sound generating device for inhibiting the polarization phenomenon in the vibration process is enhanced, and the vibration consistency is good. The existing diaphragm made of engineering plastics has low damping, the loss factor of the diaphragm is usually less than 0.01, and the damping property is small.
Preferably, the loss factor of the diaphragm provided by the invention is greater than 0.1.
Fig. 2 is a test curve of vibration displacement of different parts of a diaphragm of a sound generating device under different frequencies according to an embodiment of the present invention. Fig. 3 is a test curve of vibration displacement of different parts of a conventional diaphragm under different frequencies.
Wherein, the vibrating diaphragm is a rectangular corrugated rim vibrating diaphragm. The abscissa is frequency (Hz) and the ordinate is loudness displacement (mm). And (4) taking points at the edge position and the center position of the center part of the diaphragm for testing.
It can be seen that the curves in fig. 2 are more concentrated, while the curves in fig. 3 are more dispersed. This indicates that: the vibrating diaphragm provided by the embodiment of the invention has the advantages that the vibration consistency of all parts is better, the swinging vibration of the vibrating diaphragm is less in the vibration process, and the tone quality and the listening stability are better.
Optionally, the shore hardness of the diaphragm provided by the invention is in a range of 30 to 95A. The resonant frequency F0 of the sound generating device is proportional to the modulus, stiffness and thickness of the diaphragm, and for neoprene, the modulus is proportional to the stiffness. Therefore, the modulus of the diaphragm can be expressed in terms of stiffness.
The strength and hardness of the chloroprene rubber material can be adjusted by the inorganic filler reinforcing agent. Generally, the higher the strength and hardness of the neoprene rubber material is, the higher the F0 of the prepared diaphragm is, and accordingly, the loudness of the sound generating device is reduced and the bass performance is deteriorated. FIG. 4 is a graph of the impedance of diaphragms of the same thickness but different stiffness. As can be seen from fig. 4, as the stiffness increases, the resonance frequency F0 of the sound emitting device increases sharply.
The diaphragm of the sound production device provided by the invention can be a corrugated diaphragm or a flat diaphragm, for example. The resonant frequency F0 of the sound generating device is proportional to the Young modulus and the thickness of the vibrating diaphragm, the change of F0 can be realized by changing the thickness and the Young modulus of the vibrating diaphragm of the sound generating device, and the specific regulation principle is as follows:
Figure BDA0002256434310000121
wherein, Mms is the equivalent vibration quality of sound generating mechanism, and Cms is the equivalent compliance of sound generating mechanism:
wherein, Cm1For compliance with the elastic wave, Cm2The diaphragm compliance is achieved. When there is no elastic wave design, the equivalent compliance of the sounding device is the compliance of the vibrating diaphragm:
Figure BDA0002256434310000123
wherein W is the total width of the bending ring part of the diaphragm, and t is the thickness of the diaphragm; dvc is the joint outer diameter of the vibrating diaphragm and the voice coil; e is the Young modulus of the vibrating diaphragm material; u is the Poisson's ratio of the vibrating diaphragm material.
It can be seen that the resonant frequency F0 of the sound generating device is proportional to the modulus and thickness of the diaphragm. The modulus of the diaphragm is proportional to its stiffness. Therefore, hardness may be used instead of its modulus. To obtain a full bass and comfortable hearing, the diaphragm should have sufficient stiffness and damping while the sound generator has a low resonance frequency F0. The size of F0 can be adjusted by one skilled in the art by adjusting the stiffness and thickness of the loudspeaker diaphragm.
The Shore hardness of the diaphragm is preferably 30-80A, and the thickness of the diaphragm is 30-120 μm. Within the above preferred range, the resonance frequency F0 of the sound generating device can be made to reach 150-1500 Hz. The low-frequency performance of the sound generating device is excellent.
Optionally, the diaphragm provided by the invention may be a single-layer structure, and may also be a multi-layer composite diaphragm. The single-layer diaphragm is a diaphragm formed by a layer of chloroprene rubber film layer. The composite diaphragm is formed by sequentially laminating a plurality of chloroprene rubber film layers. Or, the composite diaphragm may include at least one neoprene film layer, and the neoprene film layer is bonded and compounded with a film layer made of other materials to form a composite diaphragm made of multiple materials. In addition, the multiple film layers can be compounded in a hot pressing mode and the like, and the composite diaphragm is further formed. The composite diaphragm may be a two-layer, three-layer, four-layer or five-layer composite diaphragm, which is not limited in the present invention. At least one film layer in the composite diaphragm is a chloroprene rubber film layer made of the chloroprene rubber provided by the invention.
For the chloroprene rubber film layer, the thickness thereof can be selected from 10 to 200. mu.m, preferably from 30 to 120. mu.m. When the thickness of the chloroprene rubber film layer is within the range, the performance requirement and the assembly space requirement of the sound generating device can be better met.
The thickness of the diaphragm affects its acoustic performance. Generally, a lower thickness affects the reliability of the diaphragm, while a greater thickness affects the sensitivity of the diaphragm. Therefore, the thickness of the diaphragm provided by the invention can be controlled to be 30-120 μm. When the thickness range of the single-layer chloroprene rubber diaphragm is 30-120 mu m, the thickness range can ensure that the sensitivity of the sound production device diaphragm is higher, and the elastic performance and the rigidity performance of the diaphragm can meet the manufacturing requirements of the sound production device. In particular, it can be applied in miniature sound-generating devices. And, the vibrating diaphragm is as the weakest original paper among the sound generating mechanism, vibrations the in-process repeatedly, can guarantee long-time normal use, and then extension sound generating mechanism's life.
The invention also provides a comparison curve chart of a specific implementation mode of the diaphragm provided by the invention and the conventional diaphragm, as shown in fig. 5. Fig. 5 shows the loudness test curves (SPL curves) for two diaphragms at different frequencies. Wherein, the vibrating diaphragm is a corrugated rim vibrating diaphragm. The abscissa is frequency (Hz) and the ordinate is loudness.
In fig. 5, a solid line is a test curve of the diaphragm provided by the present invention. The dotted line is the test curve for a conventional diaphragm. From the SPL curve, it can be seen that the intermediate frequency performance of the two diaphragms is similar. And F0 of the sound generating device adopting the diaphragm provided by the invention is 835 Hz. The F0 for a sound emitting device using a conventional diaphragm was 915 Hz. This shows that the low frequency sensitivity of the diaphragm provided by the invention is higher than that of the existing PEEK diaphragm. In other words, the vibrating diaphragm provided by the invention can enable the sound generating device to have higher loudness and comfort.
The vibrating diaphragm provided by the invention is prepared by mixing a chloroprene rubber material and an auxiliary agent and then integrally forming. The preparation method of the vibrating diaphragm provided by the invention is simple, and the prepared vibrating diaphragm can be used in small-sized electronic equipment such as earphones, intelligent watches and the like. The vibrating diaphragm provided by the invention has excellent rebound resilience, and compared with the traditional vibrating diaphragm material, the vibrating diaphragm not only can keep excellent elasticity, but also has excellent anti-fatigue property and reliability. Moreover, the product can be normally used for a long time under extreme conditions.
On the other hand, the invention also provides a miniature sound production device.
The miniature sound generating device comprises a sound generating device main body and the vibrating diaphragm made of chloroprene rubber. The molecular chain structure of the chloroprene rubber comprises an isomer of chlorinated butadiene. The vibrating diaphragm is arranged on the sound-generating device main body and is configured to be driven to vibrate so as to generate sound through vibration. The sound generating device body can be provided with a coil, a magnetic circuit system and other components, and the vibrating diaphragm is driven to vibrate through electromagnetic induction. The miniature sound production device provided by the invention has excellent acoustic performance.
Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. 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 invention. The scope of the invention is defined by the appended claims.

Claims (20)

1. The utility model provides a vibrating diaphragm for miniature sound generating mechanism which characterized in that: the diaphragm comprises at least one elastic body layer, wherein the elastic body layer is made of chloroprene rubber;
the molecular chain structure of the chloroprene rubber comprises an isomer of chlorinated butadiene;
the molecular weight of the chloroprene rubber is 10000-500000.
2. The diaphragm of claim 1, wherein: the isomers of the chlorinated butadiene comprise the following components:
trans-1, 4-structure with a content of 70-95%;
cis-1, 4-structure, content is 2% -25%;
1, 2 structure, the content is 0.1% -5%; and
3, 4, the content is 0.1-5%;
wherein, the molecular structural formula of the trans-1, 4-structure is as follows:
Figure FDA0002256434300000011
the molecular structural formula of the cis-1, 4-structure is as follows:
Figure FDA0002256434300000012
the molecular structural formula of the 1, 2 structure is as follows:
Figure FDA0002256434300000013
the molecular structural formula of the 3, 4 structure is as follows:
3. the diaphragm of claim 1, wherein: the chloroprene rubber is mixed with an inorganic filler reinforcing agent, the inorganic filler reinforcing agent is at least one of carbon black, white carbon black, nano titanium dioxide, talcum powder, precipitated calcium carbonate and barium sulfate, and the content of the inorganic filler reinforcing agent is 15-90% of the total amount of the chloroprene rubber.
4. The diaphragm of claim 3, wherein: the content of the inorganic filler reinforcing agent is 30-70% of the total amount of the chloroprene rubber.
5. The diaphragm of claim 1, wherein: the chloroprene rubber is mixed with an anti-aging agent, 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, and the content of the anti-aging agent is 0.5-10% of the total amount of the chloroprene rubber.
6. The diaphragm of claim 5, wherein: the content of the anti-aging agent is 1% -5% of the total amount of the chloroprene rubber.
7. The diaphragm of claim 1, wherein: the chloroprene rubber is mixed with a plasticizer, the plasticizer is at least one of aliphatic dibasic acid ester plasticizer, phthalate plasticizer, benzene polyacid ester plasticizer, benzoate plasticizer, polyol ester plasticizer, chlorinated hydrocarbon plasticizer, epoxy plasticizer, citrate plasticizer and polyester plasticizer, and the content of the plasticizer is 1% -10% of the total amount of the chloroprene rubber.
8. The diaphragm of claim 7, wherein: the content of the plasticizer is 3% -7% of the total amount of the chloroprene rubber.
9. The diaphragm of claim 1, wherein: the chloroprene rubber is mixed with an internal mold release agent, the internal mold release agent is at least one of stearic acid, stearate, octadecyl amine, alkyl phosphate and alpha-octadecyl-omega-hydroxy polyoxyethylene phosphate, and the content of the internal mold release agent is 0.5-5% of the total amount of the chloroprene rubber.
10. The diaphragm of claim 9, wherein: the content of the internal release agent is 1% -3% of the total amount of the chloroprene rubber.
11. The diaphragm of claim 1, wherein: the chloroprene rubber is mixed with vulcanizing agents, and the vulcanizing agents comprise metal oxide system vulcanizing agents and thiourea vulcanizing agents.
12. The diaphragm of claim 11, wherein: the metal oxide system vulcanizing agent adopts magnesium oxide, zinc oxide or calcium oxide, and the content of the metal oxide system vulcanizing agent is 2-10% of the total amount of the chloroprene rubber;
the content of the thiourea vulcanizing agent is 0.5 to 5 percent of the total amount of the chloroprene rubber.
13. The diaphragm of claim 1, wherein: the vibrating diaphragm is a single-layer vibrating diaphragm which is formed by a chloroprene rubber film layer; in the alternative, the first and second sets of the first,
the vibrating diaphragm is a composite vibrating diaphragm, the composite vibrating diaphragm comprises two layers, three layers, four layers or five layers of film layers, and the composite vibrating diaphragm at least comprises one layer of chloroprene rubber film layer.
14. The diaphragm of claim 13, wherein: the thickness of the chloroprene rubber film layer is 10-200 μm.
15. The diaphragm of claim 14, wherein: the thickness of the chloroprene rubber film layer is 30-120 mu m.
16. The diaphragm of claim 1, wherein: the hardness range of the chloroprene rubber is 30-95A.
17. The diaphragm of claim 1, wherein: the glass transition temperature range of the chloroprene rubber is-50-0 ℃.
18. The diaphragm of claim 1, wherein: the loss factor of the chloroprene rubber at room temperature is more than 0.06.
19. The diaphragm of claim 1, wherein: the elongation at break of the chloroprene rubber is more than 100%.
20. A miniature sound producing device, comprising a sound producing device body and the diaphragm of any one of claims 1-19, wherein the diaphragm is disposed on the sound producing device body, and the diaphragm is configured to produce sound by vibration.
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