CN113542985A

CN113542985A - Loudspeaker diaphragm and sound generating device

Info

Publication number: CN113542985A
Application number: CN202010307127.3A
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
Anticipated expiration: 2040-04-17
Also published as: CN113542985B

Abstract

The invention discloses a loudspeaker diaphragm and a sound production device. The loudspeaker diaphragm comprises a film layer made of a foamed thermoplastic nylon elastomer, wherein the foamed thermoplastic nylon elastomer is a foamed body prepared from a copolymer consisting of a polyamide block A and a polyether or aliphatic polyester soft segment B through a foaming method, the mass percentage of the polyamide block A is 10-95%, the glass transition temperature of the foamed thermoplastic nylon elastomer is less than or equal to 0 ℃, and the thermoplastic temperature is 80-220 ℃. The foam elastomer material has the bubbles 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 speaker vibrating diaphragm to take place deformation.

Description

Loudspeaker diaphragm and sound generating device

Technical Field

The invention relates to the technical field of electroacoustic conversion, in particular to a loudspeaker diaphragm and a sound production device.

Background

The existing loudspeaker diaphragm mostly adopts a rubber film layer (such as NBR, IIR and the like) or a soft polyurethane foam film layer. However, the above materials have poor comprehensive properties, such as high density, poor heat resistance, low elastic recovery rate, etc., which results in low loudness of the loudspeaker diaphragm and small margin for high and low temperature cycle reliability. Such a loudspeaker diaphragm cannot satisfy the requirements of high power, water resistance, and high sound quality of a loudspeaker.

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 loudspeaker diaphragm.

According to a first aspect of the present invention, a loudspeaker diaphragm is provided. The loudspeaker diaphragm comprises a film layer made of a foamed thermoplastic nylon elastomer, wherein the foamed thermoplastic nylon elastomer is a foamed body prepared from a copolymer consisting of a polyamide block A and a polyether or aliphatic polyester soft segment B through a foaming method, the mass percentage of the polyamide block A is 10-95%, the glass transition temperature of the foamed thermoplastic nylon elastomer is less than or equal to 0 ℃, and the thermoplastic temperature is 80-220 ℃.

Alternatively, the foaming method employs a foaming agent which is at least one of nitrogen, carbon dioxide, butane, azo compounds, nitroso compounds, inorganic compounds and hydrazine.

Optionally, the breaking elongation of the foamed thermoplastic nylon elastomer is more than or equal to 80 percent

Optionally, the foamed thermoplastic nylon elastomer has a tensile strength of 0.1MPa to 50 MPa.

Optionally, the foamed thermoplastic nylon elastomer has a density of 0.1g/cm³-1g/cm³The porosity is 10% -90%.

Alternatively, in the foam, the size of the cells is from 10 μm to 200 μm.

Optionally, the material of the polyether or aliphatic polyester soft segment B is at least one of aliphatic polyester, polyethylene glycol, polycaprolactone, polytetrahydrofuran ether, polyphenyl ether and polyethylene oxide (or propane); the material of the polyester hard segment A is at least one of caprolactam, dibasic acid and diamine, laurolactam and omega-aminoundecanoic acid.

Optionally, the elastic recovery rate of the film layer after 10% strain is more than or equal to 80%.

Optionally, the adhesive further comprises a glue layer, and the adhesion between the film layer and the glue layer is greater than 50g/25mm under a 180 ° peel test.

Optionally, the thickness of the film layer is 50 μm to 2000 μm.

According to a second aspect of the present disclosure, a sound emitting device is provided. This sound generating mechanism includes sound generating mechanism main part and foretell loudspeaker vibrating diaphragm, loudspeaker vibrating diaphragm sets up in the sound generating mechanism main part.

According to one embodiment of the disclosure, the loudspeaker diaphragm has the characteristics of good temperature resistance, good rebound resilience, small density and large amplitude.

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 test curve of loudness at different frequencies (i.e., SPL curve) for a loudspeaker diaphragm according to one embodiment of the present disclosure and a conventional rubber diaphragm.

Fig. 2 is a harmonic distortion test curve of a loudspeaker diaphragm according to one embodiment of the present disclosure and a conventional foam diaphragm.

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 disclosure, a loudspeaker diaphragm is provided. The loudspeaker diaphragm comprises a film layer made of foamed thermoplastic nylon elastomer.

The foamed thermoplastic nylon elastomer is a foamed body prepared from a copolymer consisting of polyamide block A and polyether or aliphatic polyester soft segment B by a foaming method, wherein the mass percent of the polyamide block A is 10-95%, the glass transition temperature of the foamed thermoplastic nylon elastomer is less than or equal to 0 ℃, and the thermoplastic temperature is 80-220 ℃.

The higher the content of the polyamide block a, the higher the hydrogen bond density between the molecular chains, the higher the rigidity of the molecular chains, and the higher the glass transition point of the elastomer material, the lower the low temperature resistance of the elastomer material, the higher the strength of the elastomer material, and the lower the elongation at break. The higher the expansion ratio of the elastomer material, the lower the density, the higher the porosity, the lower the strength and the lower the elongation at break of the elastomer material.

In the disclosed embodiment, the mass percentage of the polyamide block a is 10% to 95%. Within this range, the foamed thermoplastic nylon elastomer has a tensile strength of 0.1MPa to 50 MPa. The foam material with the tensile strength ensures that the loudspeaker diaphragm has good durability.

The higher the glass transition temperature, the greater the mass content of the polyamide blocks A, the greater the mechanical strength of the elastomeric material and the poorer the elastic recovery. In the disclosed embodiments, the glass transition temperature is 0 ℃ or less. The glass transition temperature enables the loudspeaker diaphragm to keep a high elastic state at normal temperature, and the rebound resilience is good.

Preferably, the glass transition temperature of the foamed thermoplastic nylon elastomer is-60 ℃ to-20 ℃. This allows the diaphragm of the loudspeaker to maintain a good elasticity during operation at ambient temperatures below 0 c, so that the loudspeaker exhibits a high sound quality. Meanwhile, the risk that the loudspeaker diaphragm is damaged in a low-temperature environment is reduced, and the reliability is higher.

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

The foaming method is a physical foaming method or a chemical foaming method. The chemical foaming method is a method of foaming an elastomer material (for example, a thermoplastic nylon elastomer) by generating a gas by a chemical method. The chemical foaming agent added into the elastomer material is decomposed after being heated, so that gas is released, and the gas forms bubbles in the elastomer forming process; alternatively, the foaming may be performed during the molding of the elastomeric material by using gases released by chemical reactions between the different components of the elastomeric 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 foam elastomer material has the bubbles 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 speaker vibrating diaphragm to take place deformation.

When the loudspeaker diaphragm is in a large-amplitude state to vibrate, the elastic material generates easy large strain, and the risk of membrane folding, membrane cracking or membrane breaking can occur during long-time vibration. The loudspeaker diaphragm with the foamed thermoplastic nylon elastomer as the base material has good flexibility, and the risk of damage of the loudspeaker diaphragm is reduced.

Wherein the size of the cells is 10 μm to 200. mu.m. Within this range, the cells are effective in reducing the density of the elastomeric material and maintain good structural strength, resiliency and temperature resistance. Cell size refers to the distance between the two points where the cells are largest.

Optionally, the material of the polyether or aliphatic polyester soft segment B is at least one of aliphatic polyester, polyethylene glycol, polycaprolactone, polytetrahydrofuran ether, polyphenyl ether and polyethylene oxide (or propane); the material of the polyester hard segment A is at least one of caprolactam, dibasic acid and diamine, laurolactam and omega-aminoundecanoic acid. The above materials all form a foam, and the cells are uniformly distributed in the foam.

Of course, the hard polyester segment A and the soft polyether or aliphatic polyester segment B are not limited to the above-mentioned examples, and can be selected by those skilled in the art according to actual needs.

Optionally, the loudspeaker diaphragm is a single-layer diaphragm, and the single-layer diaphragm is formed by a layer of foamed thermoplastic nylon elastomer film.

Or, 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 foaming thermoplastic nylon elastomer film layer.

The foamed thermoplastic nylon elastomer film layer can be used as a surface layer or an intermediate layer. When used as a surface layer, the loudspeaker diaphragm can remarkably improve the resilience and durability.

The number of layers of the diaphragm can be set by those skilled in the art according to actual needs. Optionally, the loudspeaker diaphragm is a diaphragm of a micro-speaker or a diaphragm of a speaker device.

In one example, the blowing agent is at least one of nitrogen, carbon dioxide, butane, azo compounds, nitroso compounds, inorganic compounds, and hydrazine. The blowing agents described above are all capable of forming uniform bubbles within the elastomeric material.

For example, the physical foaming method forms a foam by supercritical foaming. During preparation, firstly, a foaming agent such as carbon dioxide or nitrogen in a supercritical state is injected into a closed container, so that the foaming agent and the molten copolymer are fully and uniformly mixed and diffused to form single-phase mixed sol; then, the sol is introduced into a mold cavity or an extrusion die to cause a large pressure drop of the sol, thereby causing gas to be precipitated to form a large number of bubble nuclei. In the subsequent cooling and forming process, bubble nuclei in the sol grow and are formed continuously, and finally the foaming body is obtained.

For example, the size of the cells is in the range of 5 μm to 200 μm, and in this range the cells are effective in reducing the density of the elastomeric material and maintaining good structural strength, resilience and temperature resistance.

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

The size of the bubbles has a positive correlation with the content of blowing agent. When the content of the foaming agent is less, the bubbles and the bubbles are arranged loosely, the walls of the bubbles are thicker, and the size change of the bubbles is smaller; when the content of the foaming agent is high, the cells are closely arranged, the cell walls are thinned, and fusion between the cells occurs, resulting in an increase in the size of the cells and a decrease in the density.

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 loudspeaker diaphragm at low temperature is.

In this example, the elongation at break of the elastomer material is greater than or equal to 80%, and the loudspeaker diaphragm is not easy to have reliability problems such as membrane rupture and the like in module use.

In addition, the elongation at break of the elastomer material is more than or equal to 80 percent, so that the vibration displacement of the loudspeaker diaphragm is larger, and the loudness is larger. And the reliability and durability are good, and the flexibility of the material is better. The greater the elongation at break, the greater the ability of the loudspeaker 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 loudspeaker diaphragm is larger, and the loudness is larger.

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

In one example, the foamed thermoplastic nylon elastomer has a density of 0.1g/cm³-1g/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.

In the foam, the higher the content of the foaming agent, the higher the expansion ratio, and the lower the density of the elastomer material. While too low a density leads to a reduction in the mechanical strength of the material. In the use, the loudspeaker vibrating diaphragm is easy to crack and difficult to meet the use requirement. Within the range, the loudspeaker diaphragm has moderate density and high mechanical property and is not easy to crack.

Further, the density was 0.2g/cm³-0.8g/cm³The porosity is 20-80%. Within the range, the foam has good resilience and low density, and the prepared loudspeaker diaphragm has large amplitude and low polarization.

Preferably, the film layer has a density of 0.1g/cm³-0.8g/cm³. Under the density, compared with the rubber corrugated diaphragm, the corrugated diaphragm prepared from the foamed thermoplastic nylon elastomer has smaller mass, so that the sounding device has higher loudness.

Fig. 1 is a test curve of loudness of a loudspeaker diaphragm according to one embodiment of the present disclosure at different frequencies from a conventional rubber diaphragm (i.e., SPL curve) where the abscissa is frequency in units of: hz; the ordinate is loudness, in units: dB. The solid line (curve a in fig. 1) is a test curve of the loudspeaker diaphragm provided in the embodiment of the present disclosure. The dashed line (e.g., curve B in fig. 1) is a test curve of a conventional rubber diaphragm. Two kinds of vibrating diaphragms are the corrugated rim vibrating diaphragm, and the size is the same.

As shown in fig. 1, it can be seen from the SPL curve that the low frequency performance of the two loudspeaker diaphragms is similar. The F0 of the sound generating device using the diaphragm of the embodiment of the present disclosure and the conventional rubber diaphragm is 186Hz, but the frequency sensitivity of the sound generating device using the loudspeaker diaphragm of the embodiment of the present disclosure is about 2.5dB higher than that of the conventional rubber diaphragm. Therefore, the sound production device of the loudspeaker diaphragm has higher loudness and comfort level.

In one example, the content of the polyamide block A is increased, the glass transition temperature of the material is increased, the low temperature resistance is reduced, and the mechanical strength is increased.

Table 1 shows the relationship between the mass content of the polyamide block A and the glass transition temperature and the tensile strength of the material.

As can be seen from Table 1, as the content of the polyamide block A increases, the glass transition temperature of the material increases and the low temperature resistance decreases; the tensile strength of the material is increased. 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.

TABLE 1

In one example, the film layer has an elastic recovery of 80% or greater after 10% strain. The sound production device has better transient response and lower distortion due to the good rebound resilience of the loudspeaker diaphragm.

For the cotton vibrating diaphragm of polyurethane class bubble, the vibrating diaphragm of foaming thermoplasticity nylon elastomer preparation has the elasticity region of broad, takes place in this regional meeting an emergency, and after external force got rid of, the material has excellent resilience, and like this, loudspeaker vibrating diaphragm sways the vibration few at the vibration in-process, and sound generating mechanism's tone quality and listening stability are more excellent.

Fig. 2 is a harmonic distortion test curve of a loudspeaker diaphragm according to one embodiment of the present disclosure and a conventional foam diaphragm. The THD (Total Harmonic Distoretation) curve. Wherein, the abscissa is frequency, unit: hz; the ordinate is THD. The solid line (curve a in fig. 2) is a test curve of the loudspeaker diaphragm provided in the embodiment of the present disclosure. The dotted line (e.g., curve C in fig. 2) is a test curve of the polyurethane foam diaphragm. Two kinds of vibrating diaphragms are the corrugated rim vibrating diaphragm, and the size is the same.

As can be seen from the figure, the loudspeaker diaphragm of the embodiment of the present disclosure has a lower THD than the polyurethane foam diaphragm, and has no peak or the like. This shows that the loudspeaker diaphragm of the embodiment of the present disclosure has better anti-polarization capability and better sound quality.

In one example, the loudspeaker 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.

The foamed thermoplastic nylon elastomer employed in the embodiments of the present disclosure contains a large amount of amide groups. When the loudspeaker diaphragm is manufactured, the amide group can form hydrogen bond with the adhesive layer, so that the loudspeaker diaphragm has excellent adhesion. This results in a significant improvement in the overall strength and durability of the loudspeaker diaphragm.

Preferably, the adhesion between the film layer and the subbing layer is greater than 100g/25mm (180 ° peel). When the loudspeaker device is applied, the adhesive force is high, so that the loudspeaker diaphragm is good in coordination consistency with the cone basin in the vibration process, the tone quality is pure, the loudspeaker diaphragm still keeps the initial state after vibrating for a long time, and the performance stability is high.

In one example, the thickness of the film layer is 50 μm to 2000 μm. The larger the thickness is, the higher the structural strength of the loudspeaker diaphragm is, but the lower the sound sensitivity is; the smaller the thickness, the higher the sensitivity of the loudspeaker diaphragm, but the lower the structural strength. Within the thickness range, the loudspeaker diaphragm has 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.

According to another embodiment of the present disclosure, a sound generating device is provided. This sound generating mechanism includes sound generating mechanism main part and foretell loudspeaker vibrating diaphragm, loudspeaker vibrating diaphragm sets up in the sound generating mechanism main part. The sound generating device is a micro speaker or a horn device.

The sound generating device has the characteristics of high loudness, high sensitivity, small distortion and good durability.

In the embodiments of the present disclosure, the differences between the embodiments are mainly described, 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 view of brevity of the text.

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

1. A loudspeaker diaphragm is characterized by comprising a film layer made of a foaming thermoplastic nylon elastomer,

2. The loudspeaker diaphragm of claim 1 where the foaming process uses a foaming agent that is at least one of nitrogen, carbon dioxide, butane, azo compounds, nitroso compounds, inorganic compounds, and diamines.

3. The loudspeaker diaphragm of claim 1 where the elongation at break of the foamed thermoplastic nylon elastomer is greater than or equal to 80%

4. The loudspeaker diaphragm of claim 1 where the foamed thermoplastic nylon elastomer has a tensile strength of 0.1MPa to 50 MPa.

5. The loudspeaker diaphragm of claim 1 where the foamed thermoplastic nylon elastomer has a density of 0.1g/cm³-1g/cm³The porosity is 10% -90%.

6. The loudspeaker diaphragm of claim 1 where in the foam, the size of the cells is 10 μm to 200 μm.

7. The loudspeaker diaphragm of claim 1, wherein the material of the polyether or the 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 material of the polyester hard segment A is at least one of caprolactam, dibasic acid and diamine, laurolactam and omega-aminoundecanoic acid.

8. The loudspeaker diaphragm of claim 1 where the elastic recovery of the membrane layer after 10% strain is greater than or equal to 80%.

9. The loudspeaker diaphragm of claim 1 further comprising a glue layer, wherein the adhesion between the film layer and the glue layer is greater than 50g/25mm under a 180 ° peel test.

10. The loudspeaker diaphragm of claim 1 where the thickness of the membrane layer is 50 μm to 2000 μm.

11. The loudspeaker diaphragm of claim 1, wherein the loudspeaker diaphragm is a single-layer diaphragm, and the single-layer diaphragm is formed by a layer of foamed thermoplastic nylon elastomer film.

12. A sound-producing device comprising a sound-producing device main body and the loudspeaker diaphragm of any one of claims 1 to 11, the loudspeaker diaphragm being provided on the sound-producing device main body.