JP2008193370A - Speaker diaphragm and speaker using the same, and electronic equipment and device using the same speaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a speaker diaphragm used for acoustic equipment which can have characteristics and sound quality controlled with high precision, a speaker, electronic equipment, and a device. <P>SOLUTION: As an embodiment of the present invention, the speaker diaphragm is constituted by binding a material obtained by mixing at least a resin material and aramid fiber together with an organosilicon compound and carrying out injection molding. Consequently, the diaphragm is obtained which has large flexibility of physical property value setting of the diaphragm, has high elasticity and high internal loss, can secure moisture resistance reliability and strength, and further has superior outward appearance and improved productivity and size stability. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a speaker diaphragm used in various audio equipment and video equipment, and to electronic equipment and devices such as a speaker, a stereo set, and a television set using the diaphragm.

  A conventional technique will be described with reference to FIG.

  FIG. 6 is a cross-sectional view of a resin speaker diaphragm made by conventional injection molding.

  As shown in FIG. 6, the speaker diaphragm 16 was obtained by using a resin such as polypropylene and injection-molding resin pellets in a pre-set mold.

  As a kind of the resin material by these injection moldings, a single material such as polypropylene is generally often used.

  In addition, for the purpose of adjusting physical property values as a diaphragm, that is, adjusting characteristics and sound quality as a speaker, there is a blend type using different types of resins.

  Furthermore, with respect to the adjustment of physical property values that are difficult to adjust with these resins, reinforcing materials such as mica are mixed to adjust the physical property values and the characteristics and sound quality as a speaker.

For example, Patent Literature 1 and Patent Literature 2 are known as prior art literature information relating to the invention of this application.
JP-A-2-228197 JP-A-6-125593

  With respect to recent audio equipment and video equipment, as well as devices such as automobiles equipped with these equipment, performance has been dramatically improved as compared with the past due to significant advances in digital technology.

  With regard to its sound quality, the realism has been further improved with lower distortion, wider bandwidth, and higher dynamic range, and video performance has been improved dramatically due to the appearance and popularization of large modules such as high definition and plasma displays. .

  Therefore, due to the performance improvement of the electronic devices described above, there is a strong demand from the market to improve the performance of the speakers used in these electronic devices.

  On the other hand, for loudspeakers whose performance is strongly demanded by the market, it is indispensable to cope with higher performance of the diaphragm that occupies a large weight that determines the sound quality among the components of the loudspeaker.

  However, this diaphragm uses traditional paper making methods, resin injection molding and press manufacturing methods, so paper diaphragms or resin diaphragms are mainly used, making use of their respective characteristics for their applications. They have been used properly, but each has its own drawbacks.

  In other words, paper diaphragms can be easily mixed with aramid fibers and mica by wet blending, so that the physical property values can be set finely, and there is an advantage that the degree of freedom in adjusting the characteristics and sound quality as a speaker is increased. However, it has inferior moisture resistance and water resistance reliability, which are peculiar to paper, and has the disadvantage that it cannot be obtained unless a very large number of processes such as paper making are required for its production.

  On the other hand, in resin diaphragms obtained by injection molding, moisture resistance, water resistance reliability and dimensional stability can be ensured and productivity can be improved, but since inorganic fillers such as mica are used to adjust physical properties, they are uniform. However, it has the disadvantage that the adjustment range of the characteristics and sound quality of the speaker is very narrow.

  The present invention solves the above-described problems, has a large degree of freedom in adjusting characteristics and sound quality as a speaker, can secure moisture resistance, water resistance reliability and dimensional stability, has an excellent appearance, and can improve productivity. An object of the present invention is to provide a diaphragm for use.

  In order to achieve the above object, the present invention is a speaker diaphragm comprising at least a resin and an aramid fiber refined to a microfibril state, and the diaphragm is obtained by injection molding.

  With this configuration, the high elastic modulus of the aramid fiber itself can be further increased, and by maintaining high internal loss, the degree of freedom in setting the physical properties of the diaphragm is increased, and further, moisture resistance and water resistance reliability due to the resin are increased. A speaker diaphragm that can be secured can be obtained.

  As described above, the present invention comprises at least a resin and an aramid fiber refined to a microfibril state by injection molding.

  With this configuration, the entanglement between aramid fibers is improved, the high elastic modulus that is a feature of aramid fibers can be further increased, and by maintaining a high internal loss, the degree of freedom in setting the physical properties of the diaphragm is increased. In addition, it is possible to obtain a diaphragm that can secure moisture resistance reliability and strength and has an excellent appearance.

  Further, by obtaining the diaphragm by injection molding, a diaphragm having improved productivity and dimensional stability can be obtained.

  In addition, by selecting these resins and reinforcing materials that are intermixing materials from a wide range of materials and setting the mixing ratio appropriately, it is possible to achieve high-accuracy characteristics and sound quality that were previously impossible. Adjustment is possible.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
Hereinafter, the invention according to the first to nineteenth aspects of the present invention will be described with reference to the first embodiment.

  FIG. 1 is a sectional view of a diaphragm according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the diaphragm according to an embodiment of the present invention.

  As shown in FIGS. 1 and 2, the diaphragm 1 is formed by injection molding a material in which resin 1A, aramid fiber 1B, and aramid fiber 1C refined to a microfibril state are mixed.

  The aramid fiber 1C refined to the microfibril state is entangled with the aramid fiber 1B. As a result, the entanglement between the fibers is improved, and a diaphragm having higher strength and higher rigidity can be obtained.

  As for the material of the diaphragm 1, a crystalline or amorphous olefin resin is used for the resin 1A.

  By using an olefin resin, moldability can be improved, and by using different crystalline and amorphous resin materials depending on the application, it is possible to satisfy the optimum physical properties as a resin material. It becomes possible.

  This time, the resin 1A will be described with respect to an example in which polypropylene is used.

  Polypropylene is generally easily available and injection molding is easy, but the present invention is not limited to this resin, and other resins can be used depending on the desired characteristic value. can do.

  For example, when high heat resistance and high solvent resistance are required, it is possible to use an engineering plastic suitable for the application.

  Here, the aramid fiber can reproduce a bright tone with a clear feeling, and can suppress a dark and uniform tone unique to the resin.

  In general, the elastic modulus of the fiber improves as the aspect ratio (fiber length / fiber diameter) increases. In particular, a rigid fiber such as an aramid fiber has a sufficient strength even if the fiber diameter is small, and this tendency appears remarkably. Therefore, by making the aramid fiber finer to a microfibril state and making the fiber diameter 5 μm or less, it is possible to obtain a diaphragm having a high aspect ratio and a high elastic modulus.

  Moreover, the fiber length of the aramid fiber of this invention is comprised as 0.3 mm-6 mm. With this configuration, it is possible to efficiently draw out the effect when the resin is granulated and compounded and kneaded, and the productivity and quality can be improved.

  The chopped fiber-like aramid fiber has a uniform fiber length because the fiber length distribution is sharp, and has a fiber diameter of 10 to 15 μm before being refined to a microfibril state.

  Here, when the fiber length of the aramid fiber is shorter than 0.3 mm, the effect of the aramid fiber cannot be obtained efficiently and a high elastic modulus cannot be expected.

  On the other hand, when the length is longer than 6 mm, a dispersibility failure is likely to occur due to secondary aggregation resulting from the entanglement of the fibers, so that a kneading process with the resin is required for a long time. Appear and cause problems in productivity and quality, such as deteriorating the appearance.

  In addition, it is preferable to form a composite with an aramid fiber of 3 mm or less. If the fiber length is longer than this, it is difficult to form the diaphragm thinly.

  In addition, the chopped fiber aramid fiber can be used to combine long fibers with a fiber length of 1.5 mm or more and short fibers with a fiber length of less than 1.5 mm, so that the resonance can be relieved and fine sound quality can be achieved. Adjustment is possible.

  And by including the chopped fiber-like aramid fiber and the aramid fiber refined to the microfibril state, the entanglement between the aramid fibers increases, the bond strength increases, and the diaphragm with a higher elastic modulus is secured. Obtainable.

  In addition, if you want to adjust the sound quality by strengthening the diaphragm, adding some accents to the sound, or giving the sound pressure frequency characteristics a peak, mix mica, graphite, talc, and even cellulose fibers as reinforcements. It can also be configured.

  In this case, the elastic modulus can be increased by mixing mica into the reinforcing material. Moreover, when graphite is mixed, the elastic modulus and internal loss can be increased. Moreover, when talc is mixed, internal loss can be increased. Furthermore, by mixing the cellulose fiber, the cellulose fiber and the aramid fiber are entangled, and the internal loss can be increased without lowering the elastic modulus. Further, by using cellulose fibers obtained by refining part or all of the cellulose fibers to a microfibril state, the bonding force between the fibers can be increased and the elastic modulus can be increased. In addition, the elastic modulus may be improved by using inorganic minerals such as calcium carbonate and clay and high-strength fibers such as carbon fibers.

  By combining each of the above materials, the physical property value of the diaphragm can be adjusted freely and with high accuracy, and desired characteristics and sound quality can be realized.

  Moreover, what is necessary is just to use a compatibilizing agent in order to improve the adhesiveness of resin and an aramid fiber. By using an organosilicon compound as a compatibilizer, the bond strength between the resin and aramid fiber is increased and the adhesion is improved, so that energy loss is reduced and the characteristics of the aramid fiber are more effectively utilized. A diaphragm having high strength and high elastic modulus can be obtained.

  Moreover, by mixing an organosilicon compound having an amino group, the resin and the aramid fiber can be more firmly bound, and a diaphragm having a higher elastic modulus in which the physical properties of the aramid fiber functioned effectively can be obtained. it can. Note that 3-aminopropyltriethoxysilane or 3-aminopropyltrimethoxysilane is more effective as the organosilicon compound having an amino group used here.

  Hydrolyzable long-chain alkyl silanes are also effective when polypropylene is used as the resin because the long-chain portion of the alkyl group has good compatibility with olefin resins. As a result, polypropylene and aramid fibers Since the adhesiveness of is improved, the elastic modulus is also improved. The hydrolyzable long-chain alkylsilane used here preferably has 6 or more carbon atoms, and hexyltrimethoxysilane, hexyltriethoxysilane, and decyltrimethoxysilane are more effective.

  Further, a fluidity modifier may be mixed. For example, fluid paraffin or calcium stearate can be used as such a modifier. In particular, a fatty acid having an amino group is desirable. By using stearic acid amide or oleic acid amide, the diaphragm formed by injection molding can be thinned.

  In order to realize the desired characteristics and sound quality, deep know-how regarding characteristics creation and sound creation is necessary, but in general, it is often implemented by the following means.

  With regard to making the characteristics of the speaker and making the sound, it is possible to change to some extent by changing the parameters of the component parts, and it is possible to approach the desired characteristics and sound quality.

  For example, when the parameters of other components other than the diaphragm are fixed, among the speaker components, the parameters that can be varied on the diaphragm include area, shape, weight, surface thickness, etc. There is.

  Therefore, considering the case where the area, shape, weight, and surface thickness of the diaphragm are fixed at a constant level, assuming that it is an approximate stage in speaker design, the sound pressure frequency of the speaker is used under conditions other than the physical properties of the diaphragm. Characteristics and sound quality are roughly determined.

  In this case, a necessary peak or dip occurs in the sound pressure frequency characteristics, and distortion often occurs greatly in a specific frequency band.

  As for the sound quality, the timbre greatly depends on the sound pressure frequency characteristic.

  These causes are attributed to the area, shape, weight, and surface thickness of the diaphragm, and particularly due to the vibration mode of the diaphragm.

  When the present invention is applied as a diaphragm material selection means for improving the above-described unnecessary peaks, dips and distortions and obtaining good sound quality, the following results.

  First, a material that can satisfy the sound pressure frequency characteristics, sound quality, and reliability grade required for the speaker is selected as a resin, an aramid fiber, and other mixed materials.

  In this case, the resin used as the base is selected with particular emphasis on reliability such as its heat-resistant grade, and a material in which the unique tone color of each resin is close to the desired tone color is selected.

  Then, materials are selected for unnecessary peaks and dips on the sound pressure frequency characteristics to be deleted.

  In the case of countermeasures against dip, a material having resonance at that frequency is selected. On the other hand, in the case of countermeasures against peaking, a material having internal loss at that frequency is selected.

  About this material selection, resin, aramid fiber, and other mixed materials are selected in consideration of the density, elastic modulus, internal loss, timbre, resonance frequency when molded into a diaphragm shape, and the like.

  Then, the above-selected materials are kneaded to produce master batch pellets with high aramid fiber filling amount for injection molding.

  Next, a diaphragm of the present invention is obtained by injection molding using this aramid fiber high-filled master batch pellet.

  In addition to measuring and evaluating the physical properties of the diaphragm obtained in this way, a prototype of the speaker is manufactured using this diaphragm, and the final characteristics are measured and auditioned as the characteristics and sound quality of the actual speaker. Conduct a thorough evaluation.

  If the above-mentioned evaluation does not satisfy the desired characteristics and sound quality, this trial production process is repeated many times.

  Among them, not only the selection of materials but also their blending ratios will be improved to gradually approach the target characteristics and sound quality.

  By repeating the process as described above, desired characteristics and sound quality can be satisfied or finished very close.

  Furthermore, the mixing ratio of the aramid fiber to the resin of the present invention is 5% to 50% by weight. With this configuration, it is possible to efficiently draw out the effects when kneaded with the resin, and to improve productivity and quality.

  Here, when the mixing ratio of the aramid fiber is less than 5% by weight, the effect of the aramid fiber hardly appears.

  On the other hand, if it is more than 50% by weight, the kneading step is required for a long time, and injection molding becomes difficult, so that productivity and dimensional stability are lowered, and the degree of freedom in shape is reduced.

  Moreover, the aramid fiber refined | miniaturized to the microfibril state is comprised as 5 to 20 weight%.

  Here, when the aramid fiber refined to the microfibril state is less than 5% by weight, it is difficult to refine the microfibril state and form a network between the fibers, and the strength and elastic modulus are increased. I can't hope. On the other hand, when the amount is more than 20% by weight, no significant improvement in elastic modulus is observed.

  In order to increase the amount of aramid fibers more than 20% by weight and effectively increase the elastic modulus, aramid fibers refined to a microfibril state and aramid fibers in the form of chopped fibers may be mixed and used.

  As described above, the present invention is a method for setting a diaphragm physical property value by forming a speaker diaphragm by injection molding a material mixed with a resin and an aramid fiber that is at least partially refined to a microfibril state. A diaphragm having a high degree of freedom, high elastic modulus and high internal loss, which are the features of aramid fibers, excellent moisture resistance reliability and appearance, and improved productivity and dimensional stability can be obtained.

(Embodiment 2)
Hereinafter, the invention described in claim 20 of the present invention will be described using the second embodiment.

  FIG. 3 shows a cross-sectional view of a speaker according to an embodiment of the present invention.

  As shown in FIG. 3, a magnetized magnet 2 is sandwiched between an upper plate 3 and a yoke 4 to constitute an internal magnet type magnetic circuit 5.

  A frame 7 is coupled to the yoke 4 of the magnetic circuit 5. The outer periphery of any one of the diaphragms 1 to 19 is bonded to the peripheral portion of the frame 7 via an edge 9. One end of the voice coil 8 is coupled to the center of the diaphragm 1 and the other end is coupled so as to fit into the magnetic gap 6 of the magnetic circuit 5.

  In the above, the speaker having the inner magnet type magnetic circuit 5 has been described. However, the present invention is not limited to this, and the present invention may be applied to a speaker having an outer magnet type magnetic circuit.

  With this configuration, as described in the first embodiment, the degree of freedom of adjustment of characteristics and sound quality is large, and it has high elastic modulus and high internal loss, which are the characteristics of aramid fiber, and can ensure moisture resistance reliability and strength. Thus, it is possible to realize a speaker with excellent appearance and high productivity.

(Embodiment 3)
Hereinafter, the invention described in claim 21 of the present invention will be described using the third embodiment.

  FIG. 4 is an external view of an audio minicomponent system that is an electronic apparatus according to an embodiment of the present invention.

  As shown in FIG. 4, the speaker 10 of the present invention is incorporated in an enclosure 11 to constitute a speaker system, and an amplifier 12 which is an amplifying means for an electric signal input to the speaker, and a source input to the amplifier 12 And an audio mini-component system 14 that is an electronic device.

  By adopting this configuration, it is possible to realize an electronic device capable of creating characteristics, sounds, and designs with high accuracy that could not be realized in the past.

(Embodiment 4)
In the following, the fourth aspect of the present invention will be described with reference to the fourth embodiment.

  FIG. 5 shows a cross-sectional view of an automobile 15 which is an apparatus according to an embodiment of the present invention.

  As shown in FIG. 5, an automobile 15 is configured by incorporating the speaker 10 of the present invention into a rear tray or a front panel and using it as a part of car navigation or car audio.

  By adopting this configuration, it is possible to improve the degree of freedom in acoustic design of a device such as an automobile on which the speaker 10 is mounted by creating a high-accuracy characteristic, sound making, and design utilizing the features of the aramid fiber of the speaker 10. be able to.

  The speaker diaphragm, the speaker, the electronic device, and the device according to the present invention can be applied to electronic devices such as audiovisual equipment and information communication devices that require high-precision characteristics and sound creation, and further to devices such as automobiles.

Sectional drawing of the diaphragm for speakers in one embodiment of this invention The cross-sectional enlarged view of the speaker diaphragm in one embodiment of this invention Sectional drawing of the speaker in one embodiment of this invention 1 is an external view of an electronic device according to an embodiment of the present invention. Sectional drawing of the apparatus in one embodiment of this invention Sectional view of a conventional speaker diaphragm

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Diaphragm 1A Resin 1B Aramid fiber 1C Aramid fiber refined to microfibril state 2 Magnet 3 Upper plate 4 Yoke 5 Magnetic circuit 6 Magnetic gap 7 Frame 8 Voice coil 9 Edge 10 Speaker 11 Enclosure 12 Amplifier 13 Player 14 Mini component system 15 Car

Claims (22)

A loudspeaker diaphragm formed by injection molding in which resin and aramid fibers that are at least partially refined to a microfibril state are mixed. The speaker diaphragm according to claim 1, wherein the fiber diameter of the aramid fiber refined to a microfibril state is 5 μm or less. The speaker diaphragm according to claim 1, wherein the resin is a crystalline or amorphous olefin resin. The speaker diaphragm according to claim 1, wherein the resin is polypropylene. The speaker diaphragm according to claim 1, wherein the resin is an engineering plastic. The speaker diaphragm according to claim 1, wherein a part of the aramid fiber is a chopped fiber-like fiber. The speaker diaphragm according to claim 6, wherein the aramid fiber has a fiber length of 0.3 mm or more and 6 mm or less. The speaker diaphragm according to claim 6, wherein the aramid fiber is a combination of a long fiber having a fiber length of 1.5 mm or more and a short fiber having a length of less than 1.5 mm. The speaker diaphragm according to claim 1, further comprising a reinforcing material. The loudspeaker diaphragm according to claim 9, wherein the reinforcing material is mica, graphite, talc, calcium carbonate, clay, cellulose fiber, carbon fiber, or a combination thereof. The diaphragm for a speaker according to claim 10, wherein part or all of the cellulose fibers are refined to a microfibril state. The speaker diaphragm according to claim 1, further comprising a compatibilizer. 13. The speaker diaphragm according to claim 12, wherein the compatibilizing agent is an organosilicon compound. 14. The loudspeaker diaphragm according to claim 13, wherein the organosilicon compound is an organosilicon compound having an amino group or a hydrolyzable long-chain alkylsilane. The diaphragm for speaker according to claim 14, wherein the hydrolyzable long-chain alkylsilane has 6 or more carbon atoms. The speaker diaphragm according to claim 1, further comprising a fluidity modifier. 17. The loudspeaker diaphragm according to claim 16, wherein the fluidity modifying material is a fatty acid having an amino group. The speaker diaphragm according to claim 1, wherein a mixing ratio of the aramid fiber to the resin is 5% by weight or more and 50% by weight or less. The speaker diaphragm according to claim 1, wherein aramid fibers refined to a microfibril state in the mixing ratio of aramid fibers to the resin are 5 wt% or more and 20 wt% or less. A magnetic circuit, a frame coupled to the magnetic circuit, a diaphragm coupled to the outer periphery of the frame, mixed with resin and at least partially aramid fibers refined to a microfibril state, and made of injection molding; And a voice coil that is coupled to the diaphragm and that is partly disposed within a range of action of magnetic flux generated from the magnetic circuit. 21. An electronic device comprising the speaker according to claim 20 and at least an amplifier circuit for an input signal to the speaker. The apparatus which mounted the speaker of Claim 20 in the moving means.

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