CN113542992A

CN113542992A - Vibrating diaphragm and sound generating device

Info

Publication number: CN113542992A
Application number: CN202010307122.0A
Authority: CN
Inventors: 惠冰; 凌风光; 李春; 刘春发
Original assignee: Goertek Inc
Current assignee: Goertek Inc
Priority date: 2020-04-17
Filing date: 2020-04-17
Publication date: 2021-10-22

Abstract

The embodiment of the disclosure discloses a vibrating diaphragm, a sound production device and electronic equipment. The vibrating diaphragm comprises at least one foaming body film layer, and the material of the foaming body film layer comprises a foaming body; wherein the foam is at least one of a foamed thermoplastic polyester elastomer, a foamed thermoplastic nylon elastomer, a foamed rubber, and a polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam. The film layer of the vibrating diaphragm is made of a foaming body material, and the foam holes are uniformly distributed in the foaming body, so that the overall density of the material is reduced, and the weight of the vibrating diaphragm with the same size is reduced. This makes the resilience performance of vibrating diaphragm better, and the amplitude is bigger, helps improving sound generating mechanism's sound producing effect.

Description

Vibrating diaphragm and sound generating device

Technical Field

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

Background

With the rapid development of electroacoustic technology, various types of electroacoustic products are developed. A sound generating device is an indispensable device in an electroacoustic product as an energy converter for converting an electric signal into a sound signal. At present, sound generating devices have been applied to various types of terminal electronic products, such as mobile phones, tablet computers, notebook computers, navigators, electronic books, wearable devices, and the like, and the application of the sound generating devices is very wide.

The diaphragm is provided in the vibration system of the sound generating apparatus, which is one of the more important parts in the sound generating apparatus. The diaphragm in the existing sound generating device is mostly made of a rubber film layer (e.g., nitrile rubber NBR, butyl rubber IIR, etc.) or softer thermoplastic polyurethane foam. However, the above-mentioned diaphragm has poor comprehensive properties, such as high density, low elastic recovery rate, poor heat resistance, etc., which results in low loudness of the diaphragm and small margin of high and low temperature cycle reliability. The diaphragm can not meet the requirements of high power, water resistance and high tone quality of the existing sound generating device.

Therefore, a new technical solution is needed to solve the above technical problems.

Disclosure of Invention

An object of the present disclosure is to provide a new technical solution of a diaphragm.

According to a first aspect of the present disclosure, a diaphragm is provided. The vibrating diaphragm comprises at least one foaming body film layer, and the material of the foaming body film layer comprises a foaming body; wherein the foam is at least one of a foamed thermoplastic polyester elastomer, a foamed thermoplastic nylon elastomer, a foamed rubber, and a polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam.

Optionally, two film layers are included, wherein one film layer is a substrate layer, and the substrate layer and the foam film layer are composited together.

Optionally, three film layers compounded together are included, wherein at least one film layer is a foam film layer.

Optionally, two of the foam film layers are included, the substrate layer being located between the two foam film layers;

or, the two substrate layers are included, and the foaming film layer is positioned between the two substrate layers;

or, the composite material comprises two substrate layers, the two substrate layers are adjacent, and the foaming film layer is compounded on one of the substrate layers.

Optionally, the material of the substrate layer includes rubber, thermoplastic elastomer or plastic.

Optionally, the substrate layer is rubber, a thermoplastic elastomer or plastic.

Optionally, a plurality of the film layers are bonded together by a glue layer, or by means of heat pressing.

Optionally, the substrate layer is rubber, and the rubber is ethylene propylene diene monomer, hydrogenated nitrile rubber, ethylene-acrylate rubber, styrene-butadiene rubber, natural rubber, nitrile rubber, butyl rubber, polyurethane rubber, isoprene rubber, butadiene rubber, vinyl acetate rubber, polysulfide rubber or fluororubber.

Optionally, the substrate layer is a thermoplastic elastomer, and the thermoplastic elastomer is a polystyrene, a polyester, a polyurethane, a polyamide, an organofluorine, a silicone, or a diene.

Optionally, the substrate layer is plastic, and the plastic is PP, PS, PET, PPs, PA, POM, PC, PI, or PEI.

Optionally, the foam has cells of a size of 5 to 200 μm.

According to a second aspect of the present disclosure, a sound emitting device is provided. The sound generating device comprises a vibration system and a magnetic circuit system matched with the vibration system;

wherein the vibration system comprises a diaphragm as described in any one of the above.

According to a third aspect of the present disclosure, an electronic device is provided. The electronic equipment comprises the sound generating device.

According to one embodiment of the present disclosure, the diaphragm may have various structural forms, such as a single-layer diaphragm or a composite diaphragm, and may be suitable for various types of sound generating devices, so that the sound generating device has a good sound generating effect.

In addition, the vibrating diaphragm has wider elastic area and excellent resilience.

In addition, the structure strength of the vibrating diaphragm is high, the risk of membrane rupture is not easy to occur, and the reliability is good.

Other features of the present disclosure 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 the specification, illustrate embodiments of the disclosure and together with the description, serve to explain the principles of the disclosure.

FIG. 1 is a cross-sectional view of a single layer diaphragm provided in accordance with one embodiment of the present disclosure.

FIG. 2 is a cross-sectional view of a dual-layer diaphragm provided according to one embodiment of the present disclosure.

FIG. 3 is a cross-sectional view of a three-layer diaphragm provided according to one embodiment of the present disclosure.

FIG. 4 is a cross-sectional view of a four-layer diaphragm provided according to one embodiment of the present disclosure.

FIG. 5 is a cross-sectional view of a five-layer diaphragm provided according to one embodiment of the present disclosure.

FIG. 6 is a cross-sectional view of a five-layer diaphragm provided in accordance with another embodiment of the present disclosure.

Description of reference numerals:

1-film layer, 1 a-first film layer, 1 b-second film layer, 1 c-third film layer, 1 d-fourth film layer, 1 e-fifth film layer.

Detailed Description

Various exemplary embodiments of the present disclosure 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 disclosure 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 disclosure, 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 this vibrating diaphragm that this disclosed embodiment provided, it can use in sound generating mechanism, enables sound generating mechanism and has good vocal effect. The diaphragm has various structures. The vibrating diaphragm is a corrugated ring vibrating diaphragm, a conical vibrating diaphragm or a plane vibrating diaphragm. For example, a single layer diaphragm. Or the composite diaphragm is formed by compounding a plurality of film layers. The diaphragm can meet the requirements of various assembling spaces.

The diaphragm provided by the embodiment of the disclosure, as shown in fig. 1 to 4, includes at least one foam film layer, and the material of the foam film layer includes a foam. Wherein the foam is at least one of a foamed thermoplastic polyester elastomer (TPEE), a foamed thermoplastic nylon elastomer, a foamed rubber, and a polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam (SEBS).

For example, the foam film layer is prepared from any of the foam materials described above; or the foam material is prepared by mixing the at least two foam materials. The foam film layer may be a composite of a skeleton material and the foam material. The framework material is plastic, metal, thermoplastic elastomer, etc.

The foam body has the advantages that the foam holes are uniformly distributed in the material, so that the overall density of the material is reduced, and the weight of the vibrating diaphragm with the same size is reduced. This makes the resilience performance of material better, and the amplitude is bigger, more difficult because of the weight of self leads to the vibrating diaphragm to take place deformation.

The foam is prepared by a foaming method. The foaming method includes a physical foaming method and a chemical foaming method.

The chemical foaming method is a method of foaming a material by generating a gas by a chemical method. The chemical foaming agent added into the material is decomposed after being heated, so that gas is released, and the gas forms bubbles in the material forming process; alternatively, the foaming may be performed during the material forming process by using gases released by chemical reactions between different components of the material.

The physical foaming method is a method of forming bubbles in a material during the molding of the material by physical change of a foaming agent added to the material. The physical foaming method does not affect the chemical properties and molecular structure of the elastomer material, and can form uniform bubbles in the material.

The person skilled in the art can select the foaming method and the foaming agent according to the actual needs.

Alternatively, the blowing agent used in the foaming process is at least one of nitrogen, carbon dioxide, butane, azo compounds, nitroso compounds, inorganic compounds, and diamine compounds. The foaming agent has the advantages of foaming effect, moderate forming speed of foam holes and uniform size of the foam holes.

In one example, the foam film layer has cells with a size of 5 to 200 μm. The size of the cells has a positive correlation with the amount of blowing agent used. When the amount of the foaming agent is less, the arrangement among the cells is loose, the cell walls are thick, and the change of the cell size is small. When the amount of the foaming agent is large, the cells are closely arranged, so that the cell walls are thinned, and cell-to-cell fusion may occur, which may result in increased cell size and decreased density. Within this range, the cells are uniformly distributed within the foam membrane layer. The foam film layer has moderate density.

< foamed thermoplastic polyester elastomer >

The foamed thermoplastic polyester elastomer (TPEE) is prepared from a copolymer consisting of a polyester hard segment A and a polyether or aliphatic polyester soft segment B by a foaming method.

The polyester hard segment A has higher hardness, can play a role in structural support, and can ensure that the film layer has enough rigidity. The soft segment B of polyether or aliphatic polyester has stronger fluidity and can provide the smoothness for the film layer. The prepared foaming thermoplastic polyester elastomer film layer has good resilience. In addition, the thermoplastic temperature of the foamed thermoplastic polyester elastomer film layer is lower, for example, 80 ℃ to 200 ℃, so that the molding temperature of the diaphragm is lower, and the processing of the diaphragm is easier.

Optionally, the material of the polyester hard segment A is a polymer of dibasic acid and dihydric alcohol. The dibasic acid is any one of terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid and biphenyl dicarboxylic acid. The dihydric alcohol is at least one of ethylene glycol, propylene glycol, butanediol, pentanediol and hexanediol. The reaction speed of the dibasic acid and the dihydric alcohol is high, and the conversion rate is high.

It should be noted that the types of the dibasic acid and the dihydric alcohol for preparing the polyester hard segment A are not limited to the above examples, and those skilled in the art can flexibly select the dibasic acid and the dihydric alcohol according to actual needs.

Optionally, the material of the polyether or aliphatic polyester soft segment B is at least one of aliphatic polyester, polytetrahydrofuran ether, polyphenyl ether and polyethylene oxide.

The polyester hard segment A has good crystallization performance, so that the manufactured vibrating diaphragm has high rigidity and structural strength, the durability of the vibrating diaphragm can be improved, and the service life of the vibrating diaphragm is prolonged. The polyether or aliphatic polyester soft segment B can enable the foamed thermoplastic polyester elastomer to have good fluidity, so that the prepared diaphragm is good in smoothness and good in flexibility.

In the preparation process of the foamed thermoplastic polyester elastomer: the higher the mass fraction of the polyester hard segment A is, the higher the hardness of the formed diaphragm is, but the brittleness of the diaphragm is correspondingly increased, and the diaphragm is easy to damage; the lower the mass fraction of the polyester hard segment A is, the hard segment A cannot form crystals, so that the diaphragm is easily soft in texture and low in hardness, and the toughness and resilience of the diaphragm are reduced.

In one example, the polyester hard segment a has a mass percentage of 15% to 90%, and within this range, the manufactured diaphragm can have appropriate hardness, toughness and resilience.

In one example, the foamed thermoplastic polyester elastomer is a copolymer composed of a polyester hard segment A and a polyether or aliphatic polyester soft segment B, and is prepared by a supercritical foaming molding method.

A supercritical foaming shaping method is a physical foaming shaping method, also a micropore foaming shaping method, in the injection moulding, extrusion and blow moulding shaping process, firstly injecting supercritical carbon dioxide or nitrogen and other gases into a special plasticizing device, fully and uniformly mixing and diffusing the gases and the melting raw materials to form single-phase mixed sol, then guiding the sol into a mould cavity or an extrusion opening mould, leading the sol to generate large pressure drop, thus leading the gases to be separated out to form a large amount of bubble nuclei, and in the subsequent cooling shaping process, the bubble nuclei in the sol can continuously grow up and shape to finally obtain the micropore foaming body. The foaming body prepared by the supercritical foaming forming method can improve the warping deformation of the appearance, eliminate the surface sink mark and ensure that the prepared foaming body has good appearance, which is beneficial to manufacturing a flat vibrating diaphragm.

In one example, the size of the cells of the foamed thermoplastic polyester elastomer is 10 to 200 μm. Further, the size of the cells is 30 to 150 μm. Further, the size of the cells is 30 to 150 μm.

In one example, the foamed thermoplastic polyester elastomer has a density of 0.1g/cm³～1g/cm³. Further, the density thereof was 0.2g/cm³～0.8g/cm³. The porosity of the foamed thermoplastic polyester elastomer is 10-90%.

Further, the porosity is 20% to 80%. Porosity is inversely proportional to material density, with higher porosity giving lower material density.

The density of the foam is mainly influenced by the pressure during foaming. The higher the pressure, the higher the content of the foaming agent, and the higher the expansion ratio, resulting in a decrease in the density of the material. And too low density can cause the mechanical strength of the material to be lower, so that the material is easy to crack in use and is difficult to meet the use requirement.

The density of the foamed thermoplastic polyester elastomer is 0.2g/cm³～0.8g/cm³. This allows a diaphragm made of a foamed thermoplastic polyester elastomer (TPEE) to have a smaller mass than a diaphragm of a conventional material at the same size, so that the sound emitting device can exhibit a higher loudness.

The vibrating diaphragm made of the foamed thermoplastic polyester elastomer has the characteristic of higher damping property. In the vibrating process of the vibrating diaphragm, the capability of inhibiting the polarization phenomenon of the vibrating diaphragm is strong, and the vibration consistency is good.

The vibrating diaphragm made of the foaming thermoplastic polyester elastomer has a wider elastic area. The strain occurring in this region, when the external force is removed, the material has excellent recovery. In the vibrating process of the vibrating diaphragm, the vibrating diaphragm has less swinging vibration, so that the tone quality and the listening stability are better.

In one example, the elastic recovery of the foamed thermoplastic polyester elastomer film layer after 10% strain is greater than or equal to 80%. The sound-producing device has better transient response and lower distortion due to good rebound resilience.

In one example, the foamed thermoplastic polyester elastomer has an elongation at break of 100% or more. The larger the breaking elongation is, the higher the soft segment content in the material is, the lower the glass transition temperature is, the better the flexibility is, the better the low temperature resistance is, and the reliability allowance of the vibrating diaphragm at low temperature can be improved. The elongation at break is more than 100%, and the diaphragm is not easy to break and the like in use.

In addition, the material of the soft segment B of polyether or aliphatic polyester also has an important influence on the elongation at break. The material of the soft segment B of polyether or aliphatic polyester can make the vibration displacement of the diaphragm larger and the loudness larger. And, reliability and durability are good.

The better the flexibility of the material, the greater the elongation at break, the greater the ability of the diaphragm to resist damage. When the vibrating diaphragm vibrates in a large-amplitude state, the material generates large strain, and the risk of membrane folding, membrane cracking or membrane breaking can occur after long-time vibration. And the vibrating diaphragm which takes the foaming thermoplastic polyester elastomer (TPEE) as the material can reduce the risk of the damage of the vibrating diaphragm due to good flexibility.

Furthermore, the elongation at break is more than or equal to 150 percent.

In one example, the foamed thermoplastic polyester elastomer is a film layer having a glass transition temperature of ≦ -10 deg.C. The vibrating diaphragm can keep a high elastic state at normal temperature and has good rebound resilience.

Further, the glass transition temperature is-60 ℃ to-20 ℃. When the temperature is lower than 0 ℃, the vibrating diaphragm can still keep better elasticity during working, so that the sound production device shows higher sound quality. Meanwhile, the risk of damage of the vibrating diaphragm of the sound production device in a low-temperature environment is reduced, and the reliability is higher.

The vibrating diaphragm made of the foamed thermoplastic polyester elastomer (TPEE) can meet the requirements of the sound generating device on the use in high and low temperature environments. The low temperature performance is more prominent than conventional diaphragms (e.g., PEEK diaphragms). The diaphragm has good strength and toughness even when used in a low-temperature environment. In a long-time low-temperature environment, the vibrating diaphragm has low risk of vibrating and breaking the diaphragm and high reliability.

In one example, the foamed thermoplastic polyester elastomer has a tensile strength of 0.1 to 50 MPa. Further, the tensile strength is 0.1MPa to 35 MPa.

< foamed thermoplastic nylon elastomer >

The foamed thermoplastic nylon elastomer is prepared from a copolymer consisting of a polyamide block A and a polyether or aliphatic polyester soft segment B by a foaming method.

In one example, the mass percentage of the polyamide blocks a is between 10% and 95%. As the content of the polyamide block A increases, the glass transition temperature of the material increases, the low temperature resistance decreases, and the tensile strength of the material increases. When the content of the polyamide block A is 100%, the mechanical strength of the material is greatly improved, but the toughness is obviously reduced.

Within the above range, the tensile strength of the foamed thermoplastic nylon elastomer is 0.1MPa to 50 MPa. The tensile strength may make the diaphragm durable.

Further, the tensile strength of the foamed thermoplastic nylon elastomer is 0.1MPa to 35 MPa. In this scope, good durability and good resilience performance are taken into account to the vibrating diaphragm to can realize the vibration of large amplitude, sound generating mechanism's loudness is high.

The higher the glass transition temperature, the greater the mass content of the polyamide block A, the greater the mechanical strength of the elastomeric material and the poorer the elastic recovery. Wherein the glass transition temperature of the foaming thermoplastic nylon elastomer is less than or equal to 0 ℃. The glass transition temperature enables the diaphragm to keep a high elastic state at normal temperature, and the rebound resilience is good.

Further, the glass transition temperature of the foaming thermoplastic nylon elastomer is-60 ℃ to-20 ℃. When the environmental temperature is lower than 0 ℃, the vibrating diaphragm can always keep better elasticity when working, so that the sound production device shows higher sound quality. Meanwhile, the risk that the diaphragm is damaged in a low-temperature environment is reduced.

The higher the thermoplastic temperature, the better the high temperature stability of the elastomeric material, but the lower the plasticity. The lower the thermoplastic temperature, the poorer the high temperature stability of the elastomeric material. In the embodiment of the disclosure, the thermoplastic temperature of the foamed thermoplastic nylon elastomer is 80-220 ℃, which enables the diaphragm to have good high-temperature stability and plasticity.

When the vibrating diaphragm is in large-amplitude vibration, the elastomer material is easy to generate large strain, and the risk of membrane folding, membrane cracking or membrane breaking can occur during long-time vibration. The vibrating diaphragm made of the foamed thermoplastic nylon elastomer has good flexibility, and the risk of damage of the vibrating diaphragm is reduced.

Optionally, the material of the polyamide block a is at least one of caprolactam, diacids and diamines, laurolactam and omega-aminoundecanoic acid. Optionally, the material of the polyether or aliphatic polyester soft segment B is at least one of aliphatic polyester, polyethylene glycol, polycaprolactone, polytetrahydrofuran ether, polyphenylene oxide and polyethylene oxide (or propane). The materials can form a foaming body, and the foam holes are uniformly distributed in the foaming body. Of course, the polyamide blocks A and the polyether or aliphatic polyester soft blocks B are not limited to the above examples and can be selected by the person skilled in the art according to the actual requirements.

In one example, the foaming agent used for the foamed thermoplastic nylon elastomer is at least one of nitrogen, carbon dioxide, butane, an azo compound, a nitroso compound, an inorganic compound, and a diamine compound. The above blowing agents are all capable of forming uniform cells within the material.

In one example, the foamed thermoplastic nylon elastomer is prepared by a supercritical foaming mode through a copolymer composed of polyamide blocks A and polyether or aliphatic polyester soft blocks B.

In one example, the size of the cells of the foamed thermoplastic nylon elastomer is 5 μm to 200 μm. Within this range, the cells reduce the density of the material and maintain good structural strength, resilience and temperature resistance.

Further, the size of the cells is 5 μm to 150 μm. Within this range, the physical properties of the material are more favorable.

In one example, the foamed thermoplastic nylon elastomer has an elongation at break of 80% or more. The higher the breaking elongation is, the higher the content of the polyether or aliphatic polyester soft segment B in the elastomer material is, the lower the glass transition temperature is, the better the flexibility is, the better the low temperature resistance is, and the higher the reliability allowance of the diaphragm at low temperature is. In addition, the breaking elongation of the foamed thermoplastic nylon elastomer is more than or equal to 80%, so that the vibration displacement of the vibrating diaphragm is larger, and the loudness is larger. And, the reliability, durability are good, and the better the flexibility of the material. The greater the elongation at break, the greater the ability of the diaphragm to resist damage.

Furthermore, the breaking elongation of the foamed thermoplastic nylon elastomer is more than or equal to 100%, so that the vibration displacement of the vibrating diaphragm is larger, and the loudness is larger.

In one example, the foamed thermoplastic nylon elastomer has a density of 0.1g/cm³～1g/cm³The porosity is 10-90%. The higher the content of the foaming agent, the higher the expansion ratio and the lower the density of the material. While too low a density leads to a reduction in the mechanical strength of the material. In use, the vibrating diaphragm is easy to crack and difficult to meet the use requirement. Within the range, the vibrating diaphragm has moderate density, high mechanical property and difficult cracking.

Further, the density of the foamed thermoplastic nylon elastomer is 0.2g/cm³～0.8g/cm³The porosity is 20-80%. Within the range, the foaming body has good resilience and low density, and the prepared vibrating diaphragm has the characteristics of large amplitude and low polarization. In addition, in this range, since the amplitude of the diaphragm is large, the sound emitting device exhibits a high loudness.

In one example, the elastic recovery of the foamed thermoplastic nylon elastomer film layer after 10% strain is greater than or equal to 80%. The sound production device has better transient response and lower distortion due to good rebound resilience.

The vibrating diaphragm prepared from the foaming thermoplastic nylon elastomer has a wider elastic area and takes place in the area, and after external force is removed, the material has excellent resilience, so that the vibrating diaphragm has less swinging vibration in the vibration process, and the tone quality and listening stability of the sounding device are better.

< foamed rubber >

The foaming rubber is prepared from rubber by a foaming method. For example, a physical foaming method may be employed. Further, the foam can be prepared by adopting a supercritical foaming mode.

In one example, the rubber is at least one of ethylene propylene diene monomer, hydrogenated nitrile rubber, ethylene acrylate rubber, styrene butadiene rubber, natural rubber, nitrile rubber, butyl rubber, urethane rubber, isoprene rubber, butadiene rubber, vinyl acetate rubber, polysulfide rubber, and fluororubber.

The glass transition temperature of the foaming rubber is less than or equal to-10 ℃. The prepared vibrating diaphragm can keep a high elastic state at normal temperature and has good rebound resilience.

Further, the glass transition temperature of the foaming rubber is-80 ℃ to-30 ℃. In the environment of lower than-20 ℃, the vibrating diaphragm can keep better elasticity when working, thereby leading the sound production device to show higher tone quality. Meanwhile, the risk of damage of the vibrating diaphragm of the sound production device in a low-temperature environment is reduced, and the reliability of the vibrating diaphragm can be higher.

The vibrating diaphragm made of the foamed rubber can meet the requirements of the sound generating device on the use in high and low temperature environments. The low temperature performance is more prominent than conventional diaphragms (e.g., PEEK diaphragms). Has good structural strength and toughness even when used in a low-temperature environment. And in a long-time low-temperature environment, the membrane breaking risk is low.

When the foaming method is adopted for preparing the foamed rubber, the foaming agent can be a physical foaming agent. For example, the foaming agent is at least one of foamed beads, azo compounds, nitroso compounds, inorganic compounds, diamine compounds, carbon dioxide, nitrogen, and butane. These blowing agents are capable of forming uniform cells within the material. And the foaming agents are low in cost and environment-friendly.

In one example, the foaming agent is foamed beads. The foaming micro-beads are hollow micron-sized spheres made of resin and the like.

In the preparation, first, the foamed beads are mixed into the rubber raw material and mixed uniformly. Then, the rubber raw material is introduced into a mold cavity; and then, heating the die cavity, wherein the foaming micro-beads expand in volume after being heated at a set temperature, and micro-pores are formed in the rubber material.

For example, the particle diameter of the expanded beads is 0.05 μm to 100. mu.m. The initial temperature of the expansion of the foaming micro-beads is 90-230 ℃. When the particle size of the foamed microspheres is large, the dispersion uniformity of the foamed microspheres in rubber is poor, and the cells are easy to be uneven.

Within the above size range, the expanded beads are excellent in dispersibility and can be uniformly dispersed in the rubber material.

Further, the particle diameter of the expanded beads is 0.05 to 50 μm. Within this range, the expanded beads are more easily dispersed.

In addition, the initial expansion temperature of the foamed beads should be close to or even the same as the vulcanization temperature of the rubber material, so as to ensure that the foamed beads can form cells.

For example, the amount of the blowing agent may be controlled to 0.1 to 20 wt%. Further, the addition amount of the foaming agent can be controlled to be 1 wt% to 15 wt%.

Taking the expanded beads as an example, when the content of the expanded beads is less than 10% by weight, the average size of cells formed in the expanded rubber is substantially maintained as the content of the expanded beads increases, and the density of the expanded rubber gradually decreases. When the content of the expanded beads exceeds 15% by weight, cells in the foamed rubber tend to become large and the density of the material is remarkably lowered, because the content of the expanded beads is large and small-sized cells are gathered together to form large-sized cells during the formation of the foamed rubber.

In one example, the size of the cells of the foamed rubber is 10 μm to 300. mu.m. Within this range, the cells reduce the density of the material and maintain good structural strength, resilience and temperature resistance.

Further, the size of the cells is 20 μm to 200 μm. Within this range, the physical properties of the material are more favorable.

In one example, the foamed rubber has a density of 0.1g/cm³～1.2g/cm³The porosity is 10-90%. Porosity is inversely related to the density of the elastomeric material, with higher porosity giving lower density of the elastomeric material. Within the range, the density of the vibrating diaphragm is moderate, the mechanical property is high, the cracking is not easy to generate, and the comprehensive performance of the vibrating diaphragm is good.

Further, the density of the foamed rubber is 0.2g/cm³～1.0g/cm³The porosity is 20-80%. Within the range, the foam rubber has good resilience and low density, and the prepared vibrating diaphragm has large amplitude and low polarization. Preferably, the density of the foamed rubber is 0.1g/cm³～1.1g/cm³. Under the density, compared with the vibrating diaphragm made of conventional materials, the vibrating diaphragm made of the foamed rubber has smaller mass, and the sound production device can show higher loudness.

In one example, the foamed rubber has an elongation at break of 100% or more. The greater the elongation at break, the greater the ability of the diaphragm to resist damage. When the vibrating diaphragm is used, the reliability problems such as diaphragm breaking and the like are not easy to occur. In addition, the breaking elongation is more than or equal to 100 percent, so that the vibration displacement of the manufactured vibrating diaphragm is larger, and the loudness is larger. And, the reliability, durability are good, and the better the flexibility of the material.

Furthermore, the breaking elongation of the foamed rubber is more than or equal to 150%, so that the vibration displacement of the manufactured vibrating diaphragm is larger, and the loudness is larger. Even when the vibrating diaphragm is in vibration under the big amplitude state, because it has good pliability, can obviously reduce the risk that the vibrating diaphragm destroyed, improve the life of vibrating diaphragm.

In one example, the tensile strength of the foamed rubber is 0.1MPa to 50 MPa. Further, the tensile strength of the foamed rubber is 0.1MPa to 35 MPa.

In one example, the elastic recovery of the foamed rubber film layer after 10% strain is greater than or equal to 80%. Due to good resilience, the sound production device has better transient response and lower distortion.

The vibrating diaphragm made of the foamed rubber material also has the characteristic of higher damping property. Therefore, the vibration system has stronger capability of inhibiting the polarization phenomenon of the vibrating diaphragm in the vibration process and good vibration consistency.

The vibrating diaphragm prepared from the foamed rubber has a wider elastic area and takes place in the area, after external force is removed, the material has excellent resilience, the vibrating diaphragm has less swinging vibration in the vibration process, and the tone quality and listening stability of the sound generating device are better.

< polystyrene-poly (ethylene-butylene) -polystyrene Block copolymer foam >

The polystyrene-poly (ethylene-butylene) -polystyrene segmented copolymer foam is prepared from a copolymer consisting of a polystyrene block and a poly (ethylene-butylene) block by a foaming method. For example, physical foaming can be used.

Further, the foam is prepared by adopting a supercritical foaming mode.

Wherein the adopted foaming agent is at least one of nitrogen, carbon dioxide, butane, azo compounds, nitroso compounds, inorganic compounds and diamine compounds.

Wherein the glass transition temperature of the polystyrene-poly (ethylene-butylene) -polystyrene segmented copolymer foam is less than or equal to-20 ℃, and the thermoplastic temperature is 80-220 ℃.

The higher the glass transition temperature, the larger the mass content of the polystyrene block, the higher the mechanical strength of the material and the poorer the elastic recovery rate. The glass transition temperature is less than or equal to minus 20 ℃, and the vibrating diaphragm can keep a high elastic state at normal temperature and has good rebound resilience.

Further, the glass transition temperature of the polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam is-80 ℃ to-40 ℃. This allows the diaphragm to maintain a good elasticity during operation at temperatures below-20 c, thereby allowing the sound generating device to exhibit a high sound quality. The risk of diaphragm damage in low temperature environments is also reduced.

In one example, the polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam has cells ranging in size from 10 μm to 200 μm.

Within this range, the cells reduce the density of the material and maintain good structural strength, resilience and temperature resistance.

Further, the size of the cells is 30 to 150 μm. Within this range, the physical properties of the material are more favorable.

In one example, the polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam has an elongation at break of 100% or more. The higher the breaking elongation, the higher the polystyrene block content in the material, the lower the glass transition temperature of the material, the better the flexibility, the better the low temperature resistance, and the higher the reliability allowance of the diaphragm at low temperature. The breaking elongation is more than or equal to 100 percent, so that the vibration displacement of the vibrating diaphragm is larger and the loudness is larger. And, the reliability, durability are good, and the better the flexibility of the material.

Furthermore, the breaking elongation of the polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam is more than or equal to 150%, so that the vibration displacement of the diaphragm is larger, and the loudness is larger.

In one example, the polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam has a tensile strength of 0.1 to 50 MPa.

The higher the content of polystyrene, the greater the steric hindrance between the molecular chains, the greater the rigidity of the molecular chains, and the higher the glass transition point of the material, the lower the low-temperature resistance of the material, the higher the strength of the material, and the lower the elongation at break. The higher the foaming ratio of the material is, the lower the density of the material, the higher the porosity, the lower the strength and the lower the elongation at break.

In one example, the polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam has a density of 0.1g/cm³～1g/cm³The porosity is 10-90%. The higher the porosity, the lower the density of the material. Within the range, the vibrating diaphragm has moderate density, high mechanical property and difficult cracking.

Further, the polystyrene-poly (ethylene-butylene) -polystyrene blockThe block copolymer foam had a density of 0.2g/cm³～0.8g/cm³The porosity is 20-80%. Within the range, the material has good resilience and low density, and the manufactured diaphragm has large amplitude and low polarization.

Preferably, the polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam has a density of 0.1g/cm³～0.8g/cm³. Under the density, the prepared diaphragm has smaller mass, and the sound production device can show higher loudness.

In one example, the polystyrene block is present in an amount of 10 to 70% by weight. The film layer prepared in the range has excellent glass transition temperature, low temperature resistance and mechanical property.

As the content of the polystyrene block increases, the glass transition temperature of the material increases, the low-temperature resistance performance decreases, and the mechanical strength increases. When the content of the polystyrene block is 80%, the mechanical strength of the material is greatly improved, but the toughness is obviously reduced. Within the range, the performance of the material meets the use requirement of the diaphragm.

In one example, the polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam film layer has an elastic recovery of 80% or more after 10% strain. The sound-producing device has better transient response and lower distortion due to good rebound resilience.

In addition, the vibrating diaphragm made of the polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam has a wider elastic area, strain occurs in the area, after external force is removed, the material has excellent resilience, the vibrating diaphragm has less swinging vibration in the vibration process, and the sound quality and listening stability of the sound generating device are better.

In one example, the diaphragm further includes a glue layer. The adhesion between the film layer and the bondline is greater than 50g/25mm under a 180 ° peel test. Within this range, the strength and durability of the entire diaphragm can be significantly improved.

Further, the adhesion between the film layer and the bondline is greater than 100g/25mm under a 180 ° peel test. The high adhesive force makes the vibrating diaphragm and the cone have good coordination consistency in the vibration process, the tone quality is pure, the vibrating diaphragm still keeps the initial state after vibrating for a long time, and the performance stability is high.

Wherein, the adhesive layer can be selected from one or more of acrylate adhesive, organic silicon adhesive and polyurethane adhesive. The adhesive film layer has good adhesive force and damping performance. The skilled person can select the desired one according to the actual need.

The vibrating diaphragm provided by the embodiment of the disclosure comprises at least one film layer. For example, it may be a single layer diaphragm. The diaphragm can also be a composite diaphragm, which includes two, three, four or five film layers.

In one example, the thickness of the film layer is 50 μm to 2000 μm. The larger the thickness, the higher the structural strength of the diaphragm, but the lower the sound sensitivity. The smaller the thickness, the higher the sensitivity of the diaphragm, but the lower the structural strength. Within the thickness range, the vibrating diaphragm can have good sound sensitivity and high structural strength.

Further, the thickness of the film layer is 100-1200 μm. In the enclosure, the loudspeaker diaphragm has better comprehensive performance.

< example 1>

The vibrating diaphragm provided by the present disclosure is a single-layer vibrating diaphragm, as shown in fig. 1, the single-layer vibrating diaphragm is formed by using a film layer 1, the film layer 1 is made of a foam, and the foam is selected from any one of a thermoplastic polyester elastomer foam (TPEE), a thermoplastic nylon elastomer foam, a foam rubber, and a polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam (SEBS).

The diaphragm is simple in structure and only comprises one film layer 1. The thickness of the diaphragm is 50-2000 μm.

Further, the thickness of the diaphragm may be 100 μm to 1200 μm. The thickness of the diaphragm can be flexibly adjusted by those skilled in the art according to the requirement of the assembly space.

Because the vibrating diaphragm is made of any one of foamed thermoplastic polyester elastomer (TPEE), foamed thermoplastic nylon elastomer, foamed rubber and polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam (SEBS), and the foamed rubber and the polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam (SEBS), the foam holes can be uniformly distributed in the vibrating diaphragm, so that the whole density of the vibrating diaphragm is lower, and the mass is lighter. And, resilience performance is good, and the amplitude is bigger during the vibration, is difficult for leading to the vibrating diaphragm to take place deformation because of the weight of self.

< example 2>

The vibrating diaphragm provided by the implementation of the disclosure is a composite vibrating diaphragm with a two-layer structure. As shown in fig. 2, the composite diaphragm includes two film layers, i.e., a first film layer 1a and a second film layer 1 b. The first film layer 1a and the second film layer 1b are both foams, but the specific materials of the two are the same or different. .

For example, the first film layer 1a is made of foamed thermoplastic polyester elastomer (TPEE), and the second film layer 1b is made of foamed thermoplastic nylon elastomer. For another example, the material of the first film layer 1a is a foamed rubber, and the material of the second film layer 1b is a polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam (SEBS). Of course, the first film layer 1a and the second film layer 1b may also be in other combinations of the above four types, and those skilled in the art may flexibly select them according to actual needs, which are not listed here.

The thicknesses of the first film layer 1a and the second film layer 1b may be the same or different, and those skilled in the art may flexibly adjust the thicknesses as needed. When the thicknesses of the two film layers are consistent, the formed diaphragm is good in uniformity and is not easy to curl or wrinkle.

In addition, the two film layers can be bonded together by adopting an adhesive layer to form the composite diaphragm. And under the 180-degree stripping test, the adhesive force between the film layer and the adhesive layer is more than 50g/25 mm. The overall strength and durability of the formed diaphragm can be significantly improved.

The first film layer 1a may be a base layer, and the second film layer 1b may be a foam film layer. The substrate layer and the foam film layer are compounded together. For example, the two may be bonded together by a glue layer, or by heat and pressure. Both of these ways enable high bond strength to be formed.

In one example, the material of the substrate layer includes rubber, thermoplastic elastomer or plastic. The material is not foamed. The foaming body film layer is compounded with the substrate layer, so that the overall strength and durability of the vibrating diaphragm can be improved.

In addition, when the rubber is used as one film layer of the substrate layer, the heat resistance and the damping performance of the vibrating diaphragm can be improved.

Optionally, the rubber is ethylene propylene diene monomer rubber, hydrogenated nitrile rubber, ethylene-acrylate rubber, styrene-butadiene rubber, natural rubber, nitrile rubber, butyl rubber, urethane rubber, isoprene rubber, butadiene rubber, vinyl acetate rubber, polysulfide rubber, or fluororubber. The rubber can improve the durability, heat resistance and damping property of the vibrating diaphragm.

Optionally, the substrate layer is a thermoplastic elastomer, and the thermoplastic elastomer is a polystyrene, a polyester, a polyurethane, a polyamide, an organofluorine, a silicone, or a diene. The thermoplastic elastomer can improve the structural strength and durability of the vibrating diaphragm.

Optionally, the substrate layer is plastic, and the plastic is PP, PS, PET, PPs, PA, POM, PC, PI, or PEI. The plastic can improve the structural strength and durability of the vibrating diaphragm.

< example 3>

The vibrating diaphragm provided by the implementation of the disclosure is a composite vibrating diaphragm with a three-layer structure. The composite diaphragm comprises three film layers, wherein at least one film layer is a foaming body film layer.

As shown in fig. 3, there are a first film layer 1a, a second film layer 1b and a third film layer 1 c. The first film layer 1a, the second film layer 1b and the third film layer 1c are all foams, and the materials of the three are the same or different.

For example, the first film layer 1a is made of a foamed thermoplastic polyester elastomer (TPEE), the second film layer 1b is made of a foamed thermoplastic nylon elastomer, and the third film layer 1c is made of a foamed rubber. For another example, the first film layer 1a is made of foam rubber, the second film layer 1b is made of polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam (SEBS), and the third film layer 1c is made of thermoplastic polyester elastomer foam (TPEE). Of course, the first film layer 1a, the second film layer 1b and the third film layer 1c may also be in other combinations of the above four types, and those skilled in the art may flexibly select them according to actual needs, which are not listed here.

The thicknesses of the first film layer 1a, the second film layer 1b and the third film layer 1c may be the same or different, and those skilled in the art may flexibly adjust the thicknesses as needed. In addition, the arrangement order of the first film layer 1a, the second film layer 1b and the third film layer 1c can also be flexibly adjusted, for example, the arrangement mode shown in fig. 3 can be adopted, but the arrangement mode is not limited to this. However, when the thicknesses of the two film layers on the surface layers are the same, the formed diaphragm is favorable in uniformity and is not easy to curl or wrinkle.

In addition, different film layers can be bonded together by adopting glue layers to form the composite diaphragm. And under the 180-degree stripping test, the adhesive force between the film layer and the adhesive layer is more than 50g/25 mm. The overall strength and durability of the formed diaphragm can be significantly improved.

At least one of the three film layers may be a base material layer. The material and compounding method of the base material layer are as described above. In a similar way, the substrate layer can obviously improve the structural strength and the durability of the vibrating diaphragm. The kind, thickness, number, etc. of the substrate layer can be selected by those skilled in the art according to actual needs.

For example, the diaphragm includes two foam film layers, and the substrate layer is located between the two foam film layers.

The diaphragm may include two substrate layers, and the foam film layer may be located between the two substrate layers. In this example, the base material layer serves as a surface layer, which makes the durability of the diaphragm more favorable.

The diaphragm may include two substrate layers, the two substrate layers are adjacent to each other, and the foam film layer is composited on one of the substrate layers.

< example 4>

The vibrating diaphragm provided by the implementation of the disclosure is a composite vibrating diaphragm with a four-layer structure. As shown in fig. 4, the composite diaphragm includes four film layers, at least one of which is a foam film layer, including a first film layer 1a, a second film layer 1b, a third film layer 1c, and a fourth film layer 1 d. The first film layer 1a, the second film layer 1b, the third film layer 1c and the fourth film layer 1d are all foams, and the specific materials of the four are the same or different.

Specifically, the first film layer 1a is made of a thermoplastic polyester elastomer foam (TPEE), the second film layer 1b is made of a thermoplastic nylon elastomer foam, the third film layer 1c is made of a foamed rubber, and the fourth film layer 1d is made of a polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam.

The thicknesses of the first film layer 1a, the second film layer 1b, the third film layer 1c and the fourth film layer 1d may be the same or different, and those skilled in the art may flexibly adjust the thicknesses as needed. In addition, the arrangement order of the first film layer 1a, the second film layer 1b, the third film layer 1c and the fourth film layer 1d can also be flexibly adjusted, for example, the arrangement mode shown in fig. 4 can be adopted, but the arrangement mode is not limited to this. However, when the thicknesses of the two film layers on the surface layers are the same, the formed diaphragm is favorable in uniformity and is not easy to curl or wrinkle.

At least one of the four film layers may be a base material layer. The material and compounding method of the base material layer are as described above. In a similar way, the substrate layer can obviously improve the structural strength and the durability of the vibrating diaphragm.

For example, the substrate layer may serve as a surface layer or an intermediate layer of the diaphragm. The kind, thickness, number, etc. of the substrate layer can be selected by those skilled in the art according to actual needs.

< example 5>

The vibrating diaphragm provided by the implementation of the disclosure can also be a composite structure comprising five film layers, wherein at least one film layer is a foaming body film layer. As shown in fig. 5, the five film layers are: the film comprises a first film layer 1a, a second film layer 1b, a third film layer 1c, a fourth film layer 1d and a fifth film layer 1e, wherein the four film layers are respectively a foamed thermoplastic polyester elastomer film layer (TPEE), a foamed thermoplastic nylon elastomer film layer, a foamed rubber film layer and a polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foamed film layer (SEBS), and one film layer can be any one of the foamed thermoplastic polyester elastomer film layer (TPEE), the foamed thermoplastic nylon elastomer film layer, the foamed rubber film layer and the polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foamed film layer (SEBS).

Of course, the present embodiment is not limited to the combination of the above-mentioned film layers. Also, the five film layers may be selected from at least two of a foamed thermoplastic polyester elastomer (TPEE), a foamed thermoplastic nylon elastomer, a foamed rubber, and a polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam (SEBS). For example, as shown in fig. 6, the first film layer 1a, the third film layer 1c, and the fifth film layer 1e employ the same kind of foam, and the second film layer 1b and the fourth film layer 1d each employ another kind of foam.

When the diaphragm includes a plurality of film layers, a person skilled in the art can flexibly adjust the specific material of each film layer according to actual needs, and the specific material is not limited to this.

The thicknesses of the first film layer 1a, the second film layer 1b, the third film layer 1c, the fourth film layer 1d, and the fifth film layer 1e may be the same or different, and those skilled in the art may flexibly adjust the thicknesses as needed. When the thicknesses of the two film layers on the surface layer are the same, the formed diaphragm is good in uniformity and not easy to curl or wrinkle.

In other embodiments, the film layer combination in the above embodiments is not limited, and those skilled in the art can reasonably adjust the material of each film layer according to the number of the film layers included in the diaphragm, the requirements, and the like, and the material is not limited thereto.

At least one of the five film layers may be a base material layer. The material and compounding method of the base material layer are as described above. In a similar way, the substrate layer can obviously improve the structural strength and the durability of the vibrating diaphragm.

According to another embodiment of the present disclosure, a sound generating device is provided. The sound generating device comprises a vibration system and a magnetic circuit system matched with the vibration system. Wherein the vibration system comprises the diaphragm of any of the above embodiments. The sound generating means may be a loudspeaker, for example. The loudspeaker is a horn device or a micro loudspeaker.

The sound generating device provided by the embodiment of the disclosure has the characteristics of good sound generating effect and good durability.

In the above embodiments, the differences between the embodiments are described in emphasis, and different optimization features between the embodiments can be combined to form a better embodiment as long as the differences are not contradictory, and further description is omitted here in consideration of brevity of the text.

Although some specific embodiments of the present disclosure have been described in detail by way of example, it should be understood by those skilled in the art that the foregoing examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. 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 disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A diaphragm, characterized in that: the material of the foaming film layer comprises a foaming body;

wherein the foam is at least one of a foamed thermoplastic polyester elastomer, a foamed thermoplastic nylon elastomer, a foamed rubber, and a polystyrene-poly (ethylene-butylene) -polystyrene block copolymer foam.

2. The diaphragm of claim 1, wherein: the composite film comprises two film layers, wherein one film layer is a substrate layer, and the substrate layer and the foaming film layer are compounded together.

3. The diaphragm of claim 1, wherein: comprises three film layers compounded together, wherein at least one film layer is a foaming body film layer.

4. The diaphragm of claim 3, wherein: the base material layer is positioned between the two foaming film layers;

5. The diaphragm of claim 1, wherein: comprises four film layers compounded together, wherein at least one film layer is a foaming body film layer; or

Comprises five film layers compounded together, wherein at least one film layer is a foaming film layer.

6. The diaphragm of claim 2 or 4, wherein: the material of the substrate layer comprises rubber, thermoplastic elastomer or plastics.

7. The diaphragm of any one of claims 2-5, wherein: the plurality of film layers are bonded together through a glue layer or through a hot pressing mode.

8. The diaphragm of claim 2 or 4, wherein: the material of the substrate layer comprises rubber, and the rubber is ethylene propylene diene monomer, hydrogenated nitrile rubber, ethylene-acrylate rubber, styrene butadiene rubber, natural rubber, nitrile rubber, butyl rubber, polyurethane rubber, isoprene rubber, butadiene rubber, vinyl acetate rubber, polysulfide rubber or fluororubber.

9. The diaphragm of claim 2 or 4, wherein: the material of the substrate layer comprises a thermoplastic elastomer, and the thermoplastic elastomer is polystyrene, polyester, polyurethane, polyamide, organic fluorine, organosilicon or diene.

10. The diaphragm of claim 2 or 4, wherein: the material of substrate layer includes the plastics, the plastics are PP, PS, PET, PPS, PA, POM, PC, PI or PEI.

11. A sound generating device, characterized by: the vibration system and the magnetic circuit system matched with the vibration system are included;

the vibration system comprises the diaphragm according to any one of claims 1 to 10.