JP2009290665A - Diaphragm for loudspeaker and loudspeaker device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diaphragm for a loudspeaker obtaining a strength in the same degree as the strength of the diaphragm for the loudspeaker using a metallic material and comparatively increasing a Young' modulus without largely lowering an internal loss while particularly expanding a reproducing band in a high compass. <P>SOLUTION: The diaphragm for the loudspeaker includes a base body composed of a thermoplastic resin and particles contained in the base body. In the diaphragm for the loudspeaker, a storage elastic modulus E' at a normal temperature in the frequency 1 kHz of a thermoplastic-resin single body configuring the base body must be larger than that E' at the normal temperature in the frequency 1 kHz. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a speaker diaphragm suitable for use in a portable electronic device such as a mobile phone, a portable radio or a PDA (Personal Digital Assistants), a speaker device mounted on a vehicle, etc., and the speaker diaphragm. The present invention relates to a speaker device.

A conventional speaker diaphragm is made of a thermoplastic resin composition containing 30 to 60% by weight of fine hollow particles having a density of 0.8 g / cm ³ or less, and the density is 0.9 g / cm ³ or less. And the elastic modulus is 18000 kg / cm ² or more. The thermoplastic resin is, for example, polypropylene, poly-4-methylpentene-1, or a mixture thereof (see, for example, Patent Document 1). Hereinafter, this technique is referred to as a first conventional example.

  In addition, some conventional speaker diaphragms are formed by molding a molding material containing ultrahigh crystalline polypropylene having a specific gravity of 0.91 or more and a crystallinity of 70% or more. . In this speaker diaphragm, in order to improve both the flexural modulus and the impact strength, the molding material is composed of 60 to 90% by weight of ultrahigh crystalline polypropylene and 10 to 40% by weight of fiber filler having an average fiber length of 6 mm or more. % (For example, refer to Patent Document 2). Hereinafter, this technique is referred to as a second conventional example.

  Among the speaker diaphragms described above, there is a so-called dome-shaped diaphragm having a substantially dome shape in which a longitudinal cross-sectional shape protrudes to the front side (sound wave emission side). Such a conventional dome-shaped diaphragm is formed between a dome-shaped portion, an edge-shaped portion formed on the outer peripheral side of the dome-shaped portion, and the dome-shaped portion and the edge-shaped portion. Some have a U-shaped recess with a voice coil disposed therein. The conventional dome-shaped diaphragm includes a reinforcing portion that reinforces the opening of the concave portion or the vicinity of the opening, and the reinforcing portion and the dome-shaped portion are integrally formed (see, for example, Patent Document 3). ). Hereinafter, this technique is referred to as a third conventional example.

JP-A-6-28496 (Claim 1, Claim 2, [0007] to [0017]) JP-A-11-75290 (Claim 1, Claim 3, [0005], [0007], [0014], [0015], [0017], FIG. 5) JP 2007-235553 A (Claim 1, Claim 3, [0007], [0011], [0012], [0016] to [0021], FIGS. 2 to 4)

  In the first and second conventional examples described above, there is a problem that sufficient strength cannot be obtained as much as that of a speaker diaphragm using a metal material. Further, the above-described conventional speaker diaphragm has a problem in that there is a limit to increasing the Young's modulus, which is one of the physical properties of the speaker diaphragm. Further, among the above-described conventional speaker diaphragms, speaker diaphragms using thermoplastic resins generally have physical properties (for example, strength, Young's modulus, internal loss, etc.). There was a problem of being greatly influenced by.

  Further, the dome-shaped diaphragm as in the third conventional example is roughly classified into a soft dome diaphragm and a hard dome diaphragm according to the material. Some soft dome diaphragms are made by impregnating a cloth such as cotton, silk, or synthetic fiber with a resin such as a phenolic resin or a silicone resin, followed by thermoforming and then applying a braking material. On the other hand, some hard dome diaphragms are molded from plastic materials, paper, phenolic resin, FRP (plastic reinforced fiber), etc., in addition to metal materials such as aluminum, titanium and beryllium, and ceramic materials such as boron.

  Among them, the hard dome diaphragm can set the high-frequency resonance frequency outside the audible range, while the internal loss is small compared to the soft dome diaphragm from the low to high frequencies, especially in the mid-range. In addition, there is a problem that the peak dip in the high frequency range is larger than the diaphragm of the soft dome due to the divided vibration and the divided resonance. On the other hand, the diaphragm of the soft dome has a problem that the peak dip in the mid range and the high range is smaller than the diaphragm of the hard dome, but the high frequency resonance frequency exists in the audible range.

  The present invention has been made in view of the above-described circumstances, and an example of an object is to solve the above-described problems, and a speaker diaphragm and a speaker that can solve these problems An object is to provide an apparatus.

  In order to solve the above problems, a speaker diaphragm according to the invention described in claim 1 includes a base made of a thermoplastic resin and particles contained in the base, and constitutes the base. The storage elastic modulus E ′ at room temperature at a frequency of 1 kHz is larger than the storage elastic modulus E ′ at room temperature at a frequency of 1 kHz of the thermoplastic resin alone.

  According to a second aspect of the present invention, there is provided a loudspeaker diaphragm having a base made of a thermoplastic resin and particles contained in the base and having substantially the same thickness as the loudspeaker diaphragm. The loss tangent tan δ at room temperature at the frequency 1 kHz is larger than the loss tangent tan δ at room temperature at a frequency of 1 kHz of the magnesium film, and the polyetherimide having substantially the same thickness as the speaker diaphragm is stored at room temperature at a frequency of 1 kHz. The storage elastic modulus E ′ at room temperature at the frequency of 1 kHz is larger than the elastic modulus E ′.

  According to a third aspect of the present invention, there is provided a loudspeaker diaphragm including a base made of a thermoplastic resin and particles contained in the base, wherein the particles include fly ash and silica fume. It is characterized by being included.

  A speaker device according to an invention described in claim 11 includes the speaker diaphragm according to any one of claims 1 to 10, a magnetic circuit, and a frame, and the speaker diaphragm, The magnetic circuit is supported by the frame, and the speaker diaphragm has a dome shape.

Embodiments of the present invention will be described below.
The present invention provides a loudspeaker that can obtain a strength comparable to that of a loudspeaker diaphragm using a metal material, can have a relatively large Young's modulus without greatly reducing internal loss, and can particularly expand the reproduction band of the high sound range. An object is to provide a diaphragm. For this purpose, the present inventors have intensively studied from the material surface and the manufacturing surface of the speaker diaphragm, and as a result, as the speaker diaphragm, a substrate made of a thermoplastic resin, and particles contained in the substrate, And having the storage elastic modulus E ′ at room temperature at a frequency of 1 kHz higher than the storage elastic modulus E ′ at room temperature at a frequency of 1 kHz of the thermoplastic resin alone constituting the substrate. As a result, the present invention was completed.

  In addition, the above-described object is to provide a frequency of a magnesium film in which the speaker diaphragm has a base composed of a thermoplastic resin and particles contained in the base and has substantially the same thickness as the speaker diaphragm. The loss tangent tan δ at room temperature at a frequency of 1 kHz is larger than the loss tangent tan δ at room temperature at 1 kHz, and the storage modulus E ′ at room temperature at a frequency of 1 kHz of polyetherimide having substantially the same thickness as the speaker diaphragm. This can also be achieved by having a large storage elastic modulus E ′ at room temperature at a frequency of 1 kHz.

  Further, the above object is that the speaker diaphragm has a base composed of a thermoplastic resin and particles contained in the base, and the particles contain fly ash and silica fume. Can also be achieved.

In the embodiment of the present invention, the thermoplastic resin that constitutes the speaker diaphragm means, for example, a resin that can be plasticized to the extent that it can be molded by heating, and the type thereof is not particularly limited, such as a film or a sheet. Any thermoplastic resin that can be molded into the speaker diaphragm can be used. Moreover, the thermoplastic resin is not particularly restricted by physical properties such as the degree of polymerization, average molecular weight, and melt flow rate. Examples of thermoplastic resins include polyethylene terephthalate, polybutylene terephthalate, polycyclohexylene dimethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate / terephthalate, polybutylene isophthalate / terephthalate, polycyclohexylene dimethylene isophthalate. Polyester such as phthalate / terephthalate, poly (p-hydroxybenzoic acid / ethylene terephthalate), non-liquid crystalline semi-aromatic polyester, non-liquid crystalline fully aromatic polyester, polycarbonate, aliphatic polyamide, aliphatic-aromatic polyamide, wholly aromatic Polyamides such as aromatic polyamide, polyoxymethylene, polyimide, polybenzimidazole, polyketone, polyetheretherketone, polyether Luketone, polyethersulfone, polyphenylene oxide, phenoxy resin, polyphenylene sulfide, liquid crystal polymer, polypropylene, polyethylene, olefin polymers such as polystyrene, ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / propylene / Non-conjugated diene copolymer, ethylene / ethyl acrylate copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / vinyl acetate / glycidyl methacrylate copolymer and ethylene / propylene-g-maleic anhydride copolymer, Examples thereof include a known mixture of one or more thermoplastic resins selected from elastomers such as olefin copolymers such as ABS, polyester polyether elastomers, and polyester polyester elastomers. That.
In particular, polyphenylene sulfide, polyamide, polycarbonate, polypropylene, polyurethane, one or a mixture of two or more liquid crystal polymers can be suitably used from the viewpoint of fluidity and filling properties.

  Further, in the speaker diaphragm according to the embodiment of the present invention, the base made of the thermoplastic resin needs to contain particles. The particles are not particularly limited as long as they can maintain the form of fine particles in the thermoplastic resin without being destroyed or melted by heat or pressure when the thermoplastic resin composition is molded and processed into a speaker diaphragm. The kind is not limited. However, as shown in FIG. 1, it is preferable or necessary that the base body 1 made of a thermoplastic resin contains fly ash 2 and silica fume 3 as the particles. is there.

  Here, fly ash is a solid particulate matter contained in combustion waste gas such as soot and ash, and is a collective term for dust collected in the dust ash, boiler, gas cooling chamber, and recombustion chamber. What you did. On the other hand, silica fume is a fine particle having a very fine spherical shape, which is mainly composed of amorphous spherical fine particles of high-purity silicon dioxide and is produced during the production of ferrosilicon, electrofused zirconia, and metallic silicon.

Fly ash is mainly composed of silicon dioxide (SiO ₂ ) and alumina (Al ₂ O ₃ ), and as minor components, ferric oxide (Fe ₂ O ₃ ), magnesium oxide (MgO), calcium oxide (CaO), Titanium monoxide (TiO) and the like are included. Silica fume, on the other hand, contains amorphous silicon dioxide (SiO ₂ ) as a main component, and contains alumina (Al ₂ O ₃ ), ferric oxide (Fe ₂ O ₃ ), calcium oxide (CaO), dioxide dioxide as minor components. Titanium (TiO ₂ ) and the like are included.

  Fly ash includes fly ash types I to IV according to the JIS A 6201 standard. In the embodiment of the present invention, the fly ash type I of the JIS standard is used. Thus, even fly ash is not fly ash type II-IV, etc., but by using a combination of fly ash type I and silica fume, compared to the case of using other fly ash types II-IV, etc. The fluidity of the resulting material is increased, the molding shrinkage rate is reduced, and thin molding is possible, so that the object of the present invention can be achieved very well.

  Further, in the embodiment of the present invention, fly ash type I has a high ratio of containing spherical particles, so the ball bearing effect is extremely high, and since there is the least amount of unburned carbon, the amount of oil absorption is the smallest and the high filling However, it has a function that the decrease in fluidity is small.

  In particular, the average particle size of the above-mentioned fly ash type I and silica fume is more preferably less than or equal to 1/10 of the average particle size of fly ash type I, preferably 1/20 or less. Is more than 1/40, these two types of fly ash type I and silica fume are densely filled, and the shrinkage of the resin component after the high-temperature test is suppressed and the dimensional stability is improved. Therefore, it is preferable. The average particle size is measured by taking a photograph using a scanning electron microscope, measuring the major axis and minor axis of each particle, calculating the average major axis and average minor axis, respectively, and calculating the average major axis and average minor axis. It is obtained by averaging.

  By combining and mixing fly ash type I and silica fume having different particle diameters in this way, a multi-particle size constituent filler is obtained, and a multi-particle size configuration in which silica fume particles of the particle size enter between the fly ash type I is used. Can do. As a result, a large amount of inorganic filler can be densely filled in the resin material, and when the molten resin 4 flows as shown in FIG. Since the fluidity of the resin 4 is improved, the speaker diaphragm can be thinly molded and the dimensional accuracy can be improved.

In addition, the silica fume having a small particle diameter is not only filled with primary particles in the resin material, but also aggregates the primary particles to form secondary to quaternary aggregate particles having an appropriate size. It is also possible to fill the gaps between relatively large grains and exert a ball bearing effect.
Furthermore, the fly ash type I or silica fume preferably has a surface with a slight unevenness in order to increase the rolling property in the molten resin during injection molding.

The fly ash type I has a particle size of 0.5 to 80 μm, preferably 0.5 to 50 μm, and the silica fume preferably has a particle size of 0.01 to 0.5 μm. Can be suitably used 0.05 to 0.5 μm, and in particular, by using a combination of fly ash type I in such a particle size range and silica fume, the resin material can be closely packed, A more effective ball bearing effect can be exhibited and dimensional accuracy can be improved.
The particle size is a value measured with a scanning electron microscope as described above.

  In particular, these fly ash type I and silica fume are preferably spherical, and can maximize the above-mentioned ball bearing effect. Here, “spherical” not only means a perfect spherical sphere, but also a slightly elliptical shape, a gourd shape, etc., and a spherical shape such as a granular shape with a somewhat delicate surface on the surface of these shapes. It is intended to include an approximate three-dimensional shape, and excludes a two-dimensional shape such as a fiber shape, a plate shape, or a scale shape, and a true sphere is preferable. That is, the granular shape has a shape that is relatively close to a true sphere. For example, those having an average major axis / average minor axis of 1 or more and less than 3 are preferable. As described above, by removing fillers having a two-dimensional shape such as fibrous, plate-like, and scale-like, the fluidity is gradually lowered even when the inorganic filler is filled in the resin material, and the good fluidity is obtained. Can be secured.

  The blending ratio of fly ash type I and silica fume is 20/80 to 80/20, preferably 35/65 to 65/35 in terms of mass ratio. This is because it may be difficult to obtain a molded product.

In the loudspeaker diaphragm according to the embodiment of the present invention, as described above, the thermoplastic resin that constitutes the substrate is formed by including the particles described above in the substrate that is composed of the thermoplastic resin. The storage elastic modulus E ′ (rigidity) at room temperature (eg, 20 ° C.) at a frequency of 1 kHz is larger than the storage elastic modulus E ′ (rigidity) at room temperature (eg, 20 ° C.) at a single frequency of 1 kHz. For example, when the base is made of polypropylene, the storage elastic modulus E ′ (rigidity) of the speaker diaphragm according to the embodiment of the present invention is the storage elastic modulus E ′ (= 4. 4 × 10 ⁹ N / m ² ). As described above, according to the embodiment of the present invention, the storage elastic modulus E ′ of the speaker diaphragm can be made relatively large, so that the high frequency limit frequency is shifted to the higher frequency side (outside the audible range). In addition, the acoustic characteristics can be improved, and in particular, the dip in the middle range can be made relatively small.

  Moreover, in the speaker diaphragm according to the embodiment of the present invention, it is preferable that the particles described above include hollow particles. Examples of the hollow particles include inorganic fine hollow particles such as glass balun, shirasu balun, fly ash balun, ceramic balun, perlite, and carbon balun, and organic fine hollow particles such as phenol resin balun, epoxy resin balun, and saran balun. be able to. Among these fine hollow particles, the inorganic fine hollow particles are preferably used in terms of uniformity, handleability, and the like. As described above, since the hollow particles are contained in the base made of the thermoplastic resin, the storage elastic modulus E ′ (rigidity) is increased while the weight of the speaker diaphragm is relatively small. be able to.

Moreover, in the speaker diaphragm according to the embodiment of the present invention, it is preferable that the particles described above include particles having a heat dissipation function. Here, examples of the particles having a heat dissipation function include mica (mica). Mica is a pulverized silicate mineral containing aluminum (Al), potassium (K), magnesium (Mg), sodium (Na), iron (Fe), and the like. Examples of mica include muscovite: KAl ₂ AlSi ₃ O ₁₀ (OH) ₂ and phlogopite: KMlog ₃ AlSi ₃ O ₁₀ (OH) ₂ . The muscovite is excellent in electrical insulation. On the other hand, phlogopite is particularly excellent in heat resistance.

  A loudspeaker diaphragm by Joule heat generated from a voice coil during driving of the loudspeaker device provided with the loudspeaker diaphragm by incorporating particles having a heat dissipation function into a substrate made of a thermoplastic resin. This prevents the physical properties (elastic modulus and internal loss) of the speaker diaphragm from changing drastically and the acoustic characteristics from changing significantly due to large changes in the physical properties of the speaker diaphragm. can do.

  Further, in the speaker diaphragm according to the embodiment of the present invention, the base composed of the thermoplastic resin contains a fiber having a heat dissipation function, and the weight of the thermoplastic resin relative to the total weight of the speaker diaphragm. The ratio is preferably smaller than the ratio of the weight of the particles to the total weight and the ratio of the weight of the fiber having the heat dissipation function to the total weight. As the fiber having a heat dissipation function, for example, carbon fiber is preferable.

  Since the base material made of thermoplastic resin contains a fiber having a heat dissipation function, the vibration for the speaker is caused by Joule heat generated from the voice coil during the driving of the speaker device having the speaker diaphragm. The temperature of the plate rises, the physical properties (elastic modulus and internal loss) of the speaker diaphragm change greatly, and the acoustic characteristics change greatly due to the large change of the physical properties of the speaker diaphragm. Can be deterred. Thereby, the stable acoustic characteristic can be provided over a long time.

  Further, in the speaker diaphragm according to the embodiment of the present invention, a magnesium film having a base composed of a thermoplastic resin and particles contained in the base and having substantially the same thickness as the speaker diaphragm. The loss tangent tan δ at room temperature at a frequency of 1 kHz is larger than the loss tangent tan δ at room temperature at a frequency of 1 kHz, and the storage modulus E ′ at room temperature at a frequency of 1 kHz of polyetherimide having substantially the same thickness as the diaphragm for speakers. Also, it is necessary that the storage elastic modulus E ′ at room temperature at a frequency of 1 kHz is large.

  The speaker diaphragm according to the embodiment of the present invention has a loss tangent (internal loss) at room temperature at a frequency of 1 kHz rather than a loss tangent tanδ at room temperature at a frequency of 1 kHz of a magnesium film having substantially the same thickness as the speaker diaphragm. Since tan δ is large, the peak dip particularly in the high range can be made relatively small, and the acoustic characteristics can be flattened.

  Further, in the speaker diaphragm according to the embodiment of the present invention, the room temperature at each of the frequencies 200 Hz and 3 kHz is higher than the storage elastic modulus E ′ at room temperature at the frequencies 200 Hz and 3 kHz of the thermoplastic resin alone constituting the substrate. It is preferable that the storage elastic modulus E ′ is large. With this configuration, even when resonance occurs in the speaker diaphragm at a low frequency or a high frequency, the physical properties (storage elastic modulus E ′) of the speaker diaphragm are stable and relatively large. , Can provide stable acoustic characteristics.

  The resin material for molding the speaker diaphragm according to the embodiment of the present invention includes a heat stabilizer, a light stabilizer, an antioxidant, a plasticizer, a lubricant, a colorant, a foaming agent, and a release agent as necessary. Additives such as agents and impact resistance improvers may be blended.

  In order to prepare the molding resin material, the resin, the particles, and a thermal stabilizer added as necessary are uniformly mixed at a predetermined ratio. The mixing method is not particularly limited as long as these components can be mixed uniformly. Fly ash type I and silica fume can be mixed in advance to form a mixed powder, or these materials can be mixed simultaneously. It is. When preparing the molding resin material, it is necessary to select mixing and kneading conditions so that the contained particles are uniformly dispersed in the thermoplastic resin without being destroyed.

  Specifically, after mixing thermoplastic resin, particles, etc. using a Banbury mixer, kneader, roll, it can be produced by using a heated melt kneader such as a single screw or twin screw extruder, In view of the uniformity of the resulting highly filled resin material, it is preferable to use a twin screw extruder.

  In addition, the thermoplastic resin to be blended is particularly preferably used in terms of handling because it is processed into a small diameter or powder like the fly ash type I and silica fume to be used from the composition uniformity and kneadability of the obtained composition. Any of pellets and powders may be used. When the amount of fly ash type I or silica fume is large, it is preferable from the viewpoint of production efficiency to use a small diameter or powder.

  In the case of using injection molding, it is preferable to mix the resin, the fly ash type I and silica fume, and form, for example, pellets, which are used as raw materials for injection molding. At a temperature equal to or higher than the softening point, a mixed material of the fly ash type I, silica fume, resin, and the like is melt-kneaded to obtain a pellet raw material for injection. The pellet raw material is melted and kneaded again in a heating cylinder inside the injection molding machine, and filled in a mold having a desired shape by an injection device, whereby a molded product can be obtained.

  The said molding resin material can be made into the target molded article with a normal molding method. For example, known molding methods such as injection molding, extrusion molding, press molding and injection molding can be used. In particular, in injection molding, it is possible to accurately form a three-dimensional arbitrary shape, and to manufacture a thin molded product having a complicated shape or a free shape with high reproducibility and dimensional accuracy.

  Here, an example of a configuration of a speaker device suitable for applying the speaker diaphragm according to the embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a cross-sectional view showing the configuration of such a speaker device 11. For example, as shown in FIG. 3, the speaker device 11 includes a magnetic circuit 15 having a plate 12, a magnet 13 such as a permanent magnet, and a yoke 14 formed in a substantially circular shape when viewed from above.

  In this magnetic circuit 15, a magnetic gap 15 a is formed between the opening edge of the yoke 14 and the end of the plate 12. A cylindrical speaker frame (frame) 16 is disposed on the outer periphery of the magnetic circuit 15, and a dome-shaped diaphragm (speaker diaphragm) 17 is supported by a support portion 16 a of the frame 16. The dome-shaped diaphragm 17 supports the voice coil 18 in the magnetic gap 15a of the magnetic circuit 15 so as to vibrate.

  The dome-shaped diaphragm 17 has a base composed of the above-described thermoplastic resin and particles contained in the base, and the storage elasticity of the thermoplastic resin alone constituting the base at room temperature at a frequency of 1 kHz. The storage elastic modulus E ′ at room temperature at the frequency of 1 kHz is larger than the rate E ′. As shown in FIG. 3, the dome-shaped diaphragm 17 has a dome-shaped portion 21, an edge-shaped portion 22, and a concave portion 23.

  The dome-shaped portion 21 is provided at the center of the dome-shaped diaphragm 17. The edge-shaped part 22 is formed on the outer peripheral part side of the dome-shaped part 21. The edge-like portion 22 includes a damper portion 22b as shown in detail in FIG. The damper portion 22b is formed in various shapes such as a cross-sectional convex shape, a cross-sectional concave shape, and a cross-sectional wave shape. Further, the outer peripheral end portion 22 a of the edge-shaped portion 22 is fixed to the frame 16. Further, a concave portion 23 is formed on the inner peripheral side of the edge-shaped portion 22.

  The concave portion 23 is formed between the dome-shaped portion 21 and the edge-shaped portion 22 and includes a groove portion having a substantially U-shaped cross section. The voice coil 18 is disposed in the recess 23 as shown in FIG. The voice coil 18 is bonded and fixed to the dome-shaped diaphragm 17 with an adhesive, for example. The edge-shaped part 22 and the recessed part 23 are integrally formed.

  As described above, in the speaker diaphragm according to the embodiment of the present invention, for example, when the base is made of polypropylene, the storage elastic modulus E ′ (rigidity) thereof is the storage elasticity of the speaker diaphragm made only of polypropylene. It becomes larger than the storage elastic modulus E ′ of the speaker diaphragm having the modulus E ′. Thus, according to the embodiment of the present invention, since the storage elastic modulus E ′ of the speaker diaphragm can be increased, the high frequency limit frequency can be shifted to a higher frequency side (outside the audible range). In addition, the acoustic characteristics can be improved, and in particular, the dip in the middle range can be made relatively small.

  Therefore, when the dome-shaped speaker device is configured by the speaker diaphragm according to the embodiment of the present invention, the speaker diaphragm made of magnesium (Mg) is made of polypropylene (PP) as compared with the dome-shaped speaker device. An elastic modulus larger than the elastic modulus of the speaker diaphragm made of and an internal loss larger than the internal loss of the speaker diaphragm made of magnesium (Mg) can be obtained. As described above, the speaker diaphragm according to the embodiment of the present invention has a wide reproduction band, a dome-shaped speaker device having features such as directivity characteristics, transient characteristics, sound quality, etc. By applying it to a tweeter (a loudspeaker device for high sounds), its function can be fully exhibited.

  FIG. 4 shows an example of the relationship between the loss tangent (internal loss) tan δ and the Young's modulus for the speaker diaphragm according to the embodiment of the present invention and the comparative example. In FIG. 4, A is an area | region of the property which the diaphragm for speakers which concerns on embodiment of this invention has. ● in A is a property of the speaker diaphragm according to an embodiment described later. On the other hand, B is a region having properties of the speaker diaphragm as a comparative example. A speaker diaphragm as a comparative example is made of polypropylene (PP) in which carbon fibers are mixed. □ in B is a property of a speaker diaphragm made of only polypropylene (PP). Further, Δ is a property of a speaker diaphragm composed only of magnesium (Mg), and x is a property of a speaker diaphragm composed only of polyetherimide.

  Next, FIG. 5 shows an example of the relationship between the material and strength of the speaker diaphragm and the comparative example according to the embodiment of the present invention. In FIG. 5, A is an area | region of the property which the diaphragm for speakers which concerns on embodiment of this invention has. On the other hand, R1 is a region having the property of the resin material of Comparative Example 1, R2 is a region of the property of the resin material using the filling material of Comparative Example 2, and M is a region of the property of the metal material. Examples of the resin material include polypropylene (PP), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and the like. Examples of the resin material using the filler include polypropylene (PP), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN) filled with fibers and inorganic materials (including filler). Examples of the metal material include aluminum (Al), magnesium (Mg), titanium (Ti), and beryllium (Be).

  As can be seen from FIGS. 4 and 5, the speaker diaphragm A according to the embodiment of the present invention has physical properties close to those of a metal material, and can increase the Young's modulus while maintaining some internal loss. . Since the Young's modulus can be increased in this way, the reproduction band can be expanded, and in particular, the high frequency reproduction band can be expanded. On the other hand, it can be seen that the speaker diaphragm B as a comparative example is highly dependent on the physical properties of polypropylene (PP), and it is difficult to ensure a wider degree of freedom.

  As described above, according to the embodiment of the present invention, the same strength as that of the speaker diaphragm using a metal material can be obtained, and the Young's modulus can be increased without greatly reducing the internal loss. Since the Young's modulus can be made relatively large, the reproduction band can be expanded, and in particular, the reproduction band in the high sound range can be expanded. Further, according to the embodiment of the present invention, the use of fly ash and silica fume can reduce the influence of the physical properties of the thermoplastic resin on the physical properties of the speaker diaphragm.

  Hereinafter, examples of the present invention will be described in more detail. However, the following examples are not intended to limit the present invention, and may be implemented with appropriate modifications within a range that can meet the purpose described above and below. These are all possible and are within the scope of the present invention.

  The speaker diaphragm according to the embodiment of the present invention is composed of polypropylene (PP), carbon fiber, silica ash, fly ash, and mica, each having a blending ratio of 16% (PP): 40% (carbon fiber). ): 34% (silica ash + fly ash): After blending at 10% (mica), it was molded using an injection compression and high speed molding machine instead of normal injection molding. Thereby, it was possible to further reduce the thickness.

  6 and 7 show an example of the relationship between the frequency and the Young's modulus and an example of the relationship between the frequency and the internal loss (tan δ) for the speaker diaphragm according to the embodiment of the present invention and the comparative example. 6 and 7, a straight line a is a characteristic straight line possessed by the speaker diaphragm according to the present embodiment, a straight line b is a characteristic straight line possessed by the speaker diaphragm composed only of magnesium (Mg), and a straight line c is mica. It is a characteristic straight line which the diaphragm for speakers comprised from the polypropylene in which 10% is contained. Further, a straight line d is a characteristic straight line possessed by a speaker diaphragm made only of polypropylene, and a straight line e is a characteristic straight line possessed by a speaker diaphragm made only of polyetherimide.

  FIG. 6 shows that although the speaker diaphragm according to the present embodiment is smaller in all frequencies compared to a speaker diaphragm composed only of magnesium (Mg), other materials (polypropylene, polyether) It can be seen that a relatively large Young's modulus is obtained with respect to the Young's modulus of the speaker diaphragm made of imide. Further, from FIG. 7, it can be seen that the loudspeaker diaphragm according to the present embodiment can obtain a large internal loss δ over all frequencies as compared with the loudspeaker diaphragm composed only of magnesium (Mg). I understand.

  FIG. 8 shows an example of the relationship between the internal loss (tan δ) and the propagation speed for the speaker diaphragm according to the embodiment of the present invention and the comparative example. In FIG. 8, ○ is a property of the speaker diaphragm according to the example of the present invention, and A is a region of the property of the speaker diaphragm according to the embodiment of the present invention. Various physical properties (specific gravity, hardness, Young's modulus, internal loss) can be adjusted within the range of A shown in FIG. 8 by controlling the type of thermoplastic resin and the amount of filler. Depending on the type of thermoplastic resin, the physical properties are similar to those of ceramics and metals. Although ceramics and metal-based materials have shape restrictions, the speaker diaphragm according to the present embodiment is made of a thermoplastic resin and thus has a degree of freedom in shape.

  Moreover, shrinkage | contraction of the thermoplastic resin component after a high temperature test can be suppressed by highly filling a filler. Furthermore, strength (Young's modulus) is improved by combining with the above-described spherical filler, fiber filler, and plate filler. Moreover, weight reduction can be achieved without impairing fluidity | liquidity by containing a spherical hollow filler.

On the other hand, in FIG. 8, ▲ is a property of a speaker diaphragm composed only of alumina (Al ₂ O ₃ ), ▽ is a property of a speaker diaphragm composed only of titanium (Ti), Δ Is a property of a speaker diaphragm made of only magnesium (Mg). Further, ▼ is a property of a speaker diaphragm composed only of polypropylene (PP), □ is a property of a speaker diaphragm composed only of poly phenylene sulfide (PPS), (2) is a property of a speaker diaphragm composed only of polyetherimide (PEI). From FIG. 8, it can be seen that the speaker diaphragm according to the embodiment of the present invention can obtain desired values for both the internal loss tan δ and the propagation velocity.

As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to these embodiments, and the design can be changed without departing from the scope of the present invention. Is included in the present invention.
For example, in the above-described embodiment, the example in which the present invention is applied only to the speaker diaphragm is shown. However, the present invention is not limited to this, and the advantages of dimensional accuracy, high heat resistance, and thin-walled molding are utilized. An integral molded product with a voice coil bobbin is also possible.

It is a conceptual diagram which shows the structure of the thermoplastic resin in which fly ash and silica fume were contained. It is a conceptual diagram which shows a mode that the thermoplastic resin containing a fly ash and a silica fume flows. It is sectional drawing which shows the structure of the dome shape speaker apparatus to which the diaphragm for speakers which concerns on embodiment of this invention is applied. It is a figure which shows an example of the relationship between internal loss (tan (delta)) and a Young's modulus about the diaphragm for speakers which concerns on embodiment of this invention, and a comparative example. It is a figure which shows an example of the relationship between material and intensity | strength about the diaphragm for speakers which concerns on embodiment of this invention, and a comparative example. It is a figure which shows an example of the relationship between a frequency and a Young's modulus about the diaphragm for speakers which concerns on the Example of this invention, and a comparative example. It is a figure which shows an example of the relationship between a frequency and internal loss (tan-delta) about the diaphragm for speakers which concerns on the Example of this invention, and a comparative example. It is a figure which shows an example of the relationship between internal loss (tan (delta)) and propagation speed about the diaphragm for speakers which concerns on the Example of this invention, and a comparative example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Base | substrate, 2 ... Fly ash, 3 ... Silica fume, 11 ... Speaker apparatus, 12 ... Plate, 13 ... Magnet, 14 ... Yoke, 15 ... Magnetic circuit, 15a ... Magnetic gap, 16 ... Frame, 16a ... Support part, 17 ... Dome-shaped diaphragm (speaker diaphragm), 18 ... Voice coil 18, 21 ... Dome-shaped part, 22 ... Edge-shaped part, 22a ... Outer edge part, 22b ... Damper part, 23 ... Recessed part,

Claims (11)

A substrate composed of a thermoplastic resin;
Particles contained in the substrate,
The loudspeaker diaphragm, wherein a storage elastic modulus E ′ at room temperature at a frequency of 1 kHz is greater than a storage elastic modulus E ′ at room temperature at a frequency of 1 kHz of the thermoplastic resin alone constituting the substrate. A substrate composed of a thermoplastic resin;
Particles contained in the substrate,
The loss tangent tan δ at room temperature at a frequency of 1 kHz is larger than the loss tangent tan δ at room temperature at a frequency of 1 kHz of a magnesium film having substantially the same thickness as the diaphragm for speakers,
The storage vibration modulus E ′ at room temperature at a frequency of 1 kHz is larger than the storage elastic modulus E ′ at room temperature at a frequency of 1 kHz of polyetherimide having substantially the same thickness as the diaphragm for speaker. Board. A substrate composed of a thermoplastic resin;
Particles contained in the substrate,
The loudspeaker diaphragm is characterized in that the particles contain fly ash and silica fume. The storage elastic modulus E ′ at room temperature at each of the frequencies 200 Hz and 3 kHz is larger than the storage elastic modulus E ′ at each of the frequencies 200 Hz and 3 kHz than the storage elastic modulus E ′ at each of the frequencies 200 Hz and 3 kHz of the thermoplastic resin constituting the substrate. The speaker diaphragm according to any one of claims 1 to 3. The speaker diaphragm according to any one of claims 1, 2, and 4, wherein the particles include fly ash and silica fume. The speaker diaphragm according to claim 3 or 5, wherein the fly ash has a particle size larger than that of the silica fume. The particles include hollow particles
The speaker diaphragm according to any one of claims 1 to 6. The particles include particles having a heat dissipation function.
The speaker diaphragm according to any one of claims 1 to 7. The base contains a fiber having a heat dissipation function,
The ratio of the weight of the thermoplastic resin to the total weight is:
The ratio of the weight of the particles to the total weight; and
The speaker diaphragm according to any one of claims 1 to 8, wherein the speaker diaphragm is smaller than a ratio of a weight of the fiber having the heat radiation function to the total weight. The thermoplastic resin is polypropylene.
The speaker diaphragm according to any one of claims 1 to 9. A speaker diaphragm according to any one of claims 1 to 10, a magnetic circuit, and a frame.
The speaker diaphragm and the magnetic circuit are supported by the frame,
The speaker diaphragm has a dome shape.
A speaker device characterized by that.

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