WO2014141389A1

WO2014141389A1 - Speaker diaphragm and speaker device

Info

Publication number: WO2014141389A1
Application number: PCT/JP2013/056847
Authority: WO
Inventors: 一春川田; 喜浩佐藤
Original assignee: パイオニア株式会社; 最上電機株式会社
Priority date: 2013-03-12
Filing date: 2013-03-12
Publication date: 2014-09-18

Abstract

Provided are: a speaker diaphragm which prevents carbon fibers from falling out, and has favorable surface uniformity; and a speaker device having such a speaker diaphragm. At least one part of the speaker diaphragm is configured from an interwoven fiber body of carbon fibers and boron-containing polyvinyl alcohol fibers.

Description

Speaker diaphragm and speaker device

The present invention relates to a speaker diaphragm and a speaker device having the speaker diaphragm.

A speaker diaphragm using carbon fiber has been proposed (Patent Document 1).
In the case of the speaker diaphragm proposed in Patent Document 1, there is a problem that a large number of carbon fiber tips protrude from the surface, resulting in a so-called “bulky” state with poor surface flatness. In addition, when used as a speaker diaphragm for a long period of time, there is a problem that carbon fibers are dropped and the characteristics of the diaphragm cannot be maintained.

Japanese Patent Publication No.59-031275

The present invention is an example of a problem to deal with such a problem. That is, it is an object to provide a speaker diaphragm having good surface smoothness, a speaker device having such a speaker diaphragm, and the like, by preventing the carbon fibers of the speaker diaphragm from dropping off.

The speaker diaphragm of the present invention is constituted by a fiber entangled body of carbon fiber and polyvinyl alcohol fiber having boron in order to solve the above-mentioned problems.

It is an electron micrograph which shows the cross section of the fiber bundle of the polyvinyl alcohol-type fiber which has a boron used by this invention. FIG. 2A is a model cross-sectional view of an example of a speaker diaphragm according to the present invention. FIG. 2B is an enlarged model cross-sectional view of the “A” portion of the speaker diaphragm in FIG. FIG. 3 is a flowchart of a method for manufacturing the speaker diaphragm shown in FIG. FIG. 4 is a model diagram showing an example 100a of the speaker device according to the present invention. FIG. 5 is a model diagram showing another example 100b of the speaker device according to the present invention. FIG. 6 is an explanatory view showing an electronic device, an automobile, and a building on which the speaker device including the speaker diaphragm according to the embodiment of the present invention is mounted. FIG. 6A shows an example mounted on an electronic device. FIG. 6B shows an example mounted on an automobile. FIG.6 (c) The example installed in buildings, such as a house.

In the loudspeaker diaphragm of the present invention, as described above, at least a part is composed of a fiber entangled body of carbon fiber and polyvinyl alcohol-based fiber (hereinafter also referred to as “entanglement fiber”) containing boron. Yes.

As the carbon fiber, generally available carbon fiber of general-purpose grades such as PAN type and pitch type and various high-performance grades such as high strength and high elasticity can be used. Moreover, as carbon fiber, the thing of length of 1 mm or more and 12 mm or less can be used, for example.

When the carbon fiber is relatively long, especially when the length of the carbon fiber is in the range of 4 mm to 12 mm, the bending rigidity of the carbon fiber is relatively large, and the Young's modulus of the speaker diaphragm can be improved. . In addition, when the carbon fiber is relatively short, especially when the length of the carbon fiber is in the range of 1 mm to 4 mm, the bending rigidity of the carbon fiber itself is relatively small, and the Young's modulus of the speaker diaphragm is reduced. Can be made. Thus, the Young's modulus of the speaker diaphragm can be adjusted by setting the length of the carbon fiber to a predetermined length.

The content of carbon fiber in the fiber entangled body is preferably 5% by weight or more from the viewpoint that both the Young's modulus and the internal loss of the speaker diaphragm can be improved. When the content of the carbon fiber in the fiber entangled body is less than 5% by weight, it may be difficult to improve both the Young's modulus and the internal loss of the speaker diaphragm.

Moreover, as the polyvinyl alcohol-based fiber having boron, a fiber composed of a composition composed of a polyvinyl alcohol-based polymer compound having boric acid or a fiber composed of a boron-crosslinked polyvinyl alcohol-based polymer compound. Etc. Here, the structure of the boron bridge | crosslinking part in two examples of the polyvinyl alcohol-type high molecular compound by which the boron bridge | crosslinking was carried out to Formula (1) and Formula (2) is shown.

The polyvinyl alcohol polymer compound having boron cross-linkage is obtained by forming a cross-linked structure with boron by adding boric acid, borate, boronic acid or the like to polyvinyl alcohol, for example. The polyvinyl alcohol here is a polymer containing vinyl alcohol units of 10 mol% or more, preferably 30 mol% or more, more preferably 50 mol% or more, and usually a homopolymer or copolymer of vinyl ester or vinyl ether. Can be obtained by hydrolysis (saponification, alcoholysis, etc.). Here, vinyl acetate is a typical example of vinyl ester, and other examples include vinyl formate, vinyl propionate, vinyl pivalate, vinyl valeate, vinyl caprate, and vinyl benzoate. Examples of the vinyl ether include t-butyl vinyl ether and benzyl vinyl ether. Moreover, the polyvinyl alcohol here may contain the following monomer unit. These monomer units include olefins such as propylene, 1-butene and isobutene excluding ethylene; unsaturated acids such as acrylic acid, methacrylic acid, maleic acid, itaconic acid and maleic anhydride, or salts thereof or the number of carbon atoms. Mono- or dialkyl esters of 1 to 18; acrylamides such as acrylamide, N-alkyl acrylamide having 1 to 18 carbon atoms, N, N-dimethyl acrylamide, 2-acrylamide propanesulfonic acid or its acid salt or quaternary salt thereof Methacrylamide, N-alkylmethacrylamide having 1 to 18 carbon atoms, N, N-dimethylmethacrylamide, 2-methacrylamideamidesulfonic acid or its salt, methacrylamidepropyldimethylamine or its acid salt or its quaternary salt, etc. of Tacrylamides; N-vinylamides such as N-vinylpyrrolidone, N-vinylformamide, and N-vinylacetamide; allyl compounds such as allyl acetate, allyl alcohol, and 8-hydroxy-1-octene; cyanides such as acrylonitrile and methacrylonitrile Vinyl ethers, vinyl ethers such as alkyl vinyl ethers having 1 to 18 carbon atoms, alkoxyalkyl vinyl ethers; vinyl fluorides such as vinyl chloride and vinylidene chloride, vinyl halides such as vinylidene fluoride; dimethylallyl alcohol, vinyl ketone, etc. .

Examples of the length of the polyvinyl alcohol fiber having boron include about 1 mm. In particular, the length of the polyvinyl alcohol fiber having boron is not limited to this, and when the Young's modulus of the speaker diaphragm is improved, the polyvinyl alcohol fiber having a relatively long boron is used, and the speaker diaphragm is used. When it is desired to reduce the Young's modulus, polyvinyl alcohol fibers having a relatively short boron can be used.

The melting temperature of the above-mentioned polyvinyl alcohol fiber having boron in water is higher than 80 ° C. By using such a fiber, when forming a diaphragm for a speaker using a mold, the fiber dissolves in hot water and adheres to the mold, and the fiber adheres to the mold and productivity decreases. Can be prevented.

Furthermore, if the polyvinyl alcohol fiber containing boron is a crimped fiber, the number of entanglement points between the fibers increases, so that friction between the fibers can easily occur, and the internal loss of the speaker diaphragm is improved. Can do. Moreover, since the entanglement point of fibers increases, the Young's modulus of the speaker diaphragm can be improved. Moreover, since the entanglement point between fibers increases, the contact of carbon fiber and the polyvinyl alcohol-type fiber which has a boron increases, and omission of carbon fiber can be suppressed.

In addition, when the cross-sectional shape of the polyvinyl alcohol-based fiber having boron is a circle or an ellipse, the fiber is prevented from cracking (for example, radial (radial) direction cracking). This is preferable because the performance of is maintained.

The speaker diaphragm according to the embodiment of the present invention includes, in addition to the above two types of fibers, other natural fibers, recycled fibers, chemical fibers, synthetic fibers, fibers selected from organic fibers and inorganic fibers (others Fiber) can be used alone or in combination of two or more. By using such other fibers, the fibers adhere to each other by hydrogen bonds generated between the fibers. By this close contact, a plurality of other fibers can capture (restrain) the above-described carbon fibers, and the carbon fibers can be prevented from dropping from the speaker diaphragm.

Other natural fibers include wood pulp fibers, non-wood pulp fibers, plant fibers, animal fibers, and the like. Examples of the wood pulp fiber include sulfite pulp and kraft pulp. Nonwood pulp fibers include bamboo and straw. Examples of plant fibers include Manila hemp and cotton. Examples of animal fibers include silk and wool. Examples of chemical fibers and synthetic fibers include fibers made of rayon, nylon, vinylon, polyester, acrylic, and the like. Examples of the organic fibers include fibers made of graphite. Examples of inorganic fibers include glass fibers, ceramic fibers, various inorganic fibers composed of silicon carbide and the like, and mineral fibers composed of basalt.

The speaker diaphragm according to the embodiment of the present invention can be manufactured by papermaking from the above materials. In addition, a speaker diaphragm having desired properties can be obtained by laminating the thus-made paper product with one or more separately produced paper products containing carbon fiber or not containing carbon fiber. can do.

The speaker diaphragm having a multilayer structure and its physical properties are shown below. The speaker diaphragm having this multilayer structure has a two-layer structure, the fiber entangled body constituting the first layer is formed of pulp (natural fiber), and the fiber entangled body constituting the second layer is pulp ( Natural fiber), carbon fiber, polyvinyl alcohol fiber containing boron (hereinafter also referred to as “boron-containing PVA fiber”) Fig. 1 shows an enlarged photograph of a cut cross section of the fiber bundle. The cross section of the single fiber is elliptical).

A model cross-sectional view of the speaker diaphragm is shown in FIG. 2A, and an enlarged model cross-sectional view of the “A” portion is shown in FIG. 2B.

In this example, the first layer is on the surface side of the speaker diaphragm 1 (surface layer: reference numeral 1A in FIG. 2B), and the second layer is on the back side of the speaker diaphragm (back surface layer: FIG. The layers are stacked so as to correspond to the symbol 1B) in b), but they may be stacked in the reverse order. In this example, the front surface layer and the back surface layer have the same weight and the same weight per unit area (hereinafter also referred to as “basis weight”).

FIG. 3 shows a flowchart of the manufacturing method of the speaker diaphragm. In step S1-1, the first component, that is, the first layer of the paper product is composed of pulp, and at the same time as or before or after this step S1-1, the second component is formed in step S2-1. The second layer is made of carbon fiber, polyvinyl alcohol fiber containing boron, and pulp.

Next, in step S3-1, these paper products are superposed and integrated in step S4-1, which is a molding process.

In this way, four types of speaker diaphragms were produced. That is, as shown in Table 1 (the numbers in the table are blending amounts (wt%)), the blending amount of the carbon fibers in the surface layer is 0 wt% (no blending of carbon fibers), 10 wt%, 20 wt%, Alternatively, four types of speaker diaphragms with 30% by weight are manufactured, and Table 2 shows the physical property measurement results of these speaker diaphragms. In preparing the surface layers of these four types of speaker diaphragms, the blending amount of the polyvinyl alcohol fiber containing boron is kept constant, and the blending amount of the pulp is decreased as the blending amount of the carbon fiber is increased. did.

From Table 2, it is understood that when the weight percent of carbon fiber is increased, the Young's modulus (propagation speed) and internal loss of the speaker diaphragm are improved. Further, it is understood that the blending amount of the carbon fiber that increases both the Young's modulus and the internal loss is 10% by weight.

The speaker diaphragm having the above laminated structure was obtained by a general heat-press molding method using a mold. In the case of the speaker diaphragm according to the embodiment of the present invention, polyvinyl alcohol having boron is used. By using the system fiber, it has a mold releasability with respect to the mold, so that it could be produced with good productivity. Further, when the surface layer of the speaker diaphragm was made of a paper product containing carbon fiber, the smoothness on the surface of the speaker diaphragm was good. Moreover, the adhesion of the carbon fiber to this papermaking was good.

In the speaker diaphragm of the present invention, of the plurality of paper products constituting the speaker diaphragm, the outer periphery of one paper product may be different from the outer periphery of the other paper product. That is, the other paper product may be laminated on a part of one paper product (partial lamination), or the other paper product may be laminated on one whole paper product (total lamination). . In addition, one paper product and the other paper product may be a surface layer and a back layer, or a surface layer and an intermediate layer (a layer between the surface layer and the back layer), or an intermediate layer and a back layer. .

Generally, in a speaker device, for example, two lead wires for speakers (kinshi wires), which are conductive members, are used as an audio signal supply line for electrically connecting an external such as an amplifier or an external power source to a voice coil. These conductive members are arranged along the front or back surface of the speaker diaphragm or by sewing the upper and lower sides of the speaker diaphragm. Here, when these conductive members are arranged in a part of a fiber entangled body composed of carbon fiber of the diaphragm and polyvinyl alcohol fiber (entanglement fiber) having boron, the conductive member and the carbon fiber are conductive, Two conductive members may be short-circuited with each other. For this reason, in the part which arrange | positions these electrically-conductive members, the fiber entanglement body comprised by the carbon fiber of a diaphragm and the fiber for entanglement is not arrange | positioned, but it is more comprised only from the material which has general insulation. The short circuit can be prevented in advance.

FIG. 4 shows an example 100a of such a speaker device.

The speaker device 100a is supported by a frame 103, a diaphragm 1a having a vibration surface 100A, a center cap 107, an edge 105, a speaker lead wire (kinshi wire) 200, a damper 106, a voice coil support 104, and a voice coil support. Voice coil 101 and magnetic circuit 102. The magnetic circuit 102 includes a magnetic gap 102G in which a magnet 102A, a yoke 102B, a plate 102C, and a voice coil 101b are disposed.

In the speaker device 100a, a speaker lead wire 200, which is an audio signal supply line for supplying an audio signal to the voice coil 101, is arranged by sewing the speaker diaphragm 1a between the front and back surfaces of the speaker diaphragm 1a. Has been.

The speaker diaphragm 1a of the speaker device 100a includes a surface layer composed of a fiber entangled body composed of carbon fibers and the above-mentioned entangled fibers, and a fiber entangled body composed of wood pulp fibers that are insulating fibers. And a back surface layer. Since the surface of the speaker diaphragm 1a is a fiber entangled body constituted by the carbon fiber and the entanglement fiber as described above, the surface thereof is smooth.

In the region 1a1 in the vicinity of the speaker lead wire 200 in the speaker diaphragm 1a, a fiber entangled body constituted by carbon fibers and the above-mentioned entangled fibers is laminated on a fiber entangled body constituted by wood pulp fibers. Not. For this reason, this area | region 1a1 of the diaphragm 1a for speakers has insulation on both front and back. In this insulating region 1a1, a short circuit between the two speaker lead wires 200 is prevented in advance, and the speaker device 100a can be driven satisfactorily.

In a general speaker device, two conductive members (kinshi wires) are used as an audio signal supply line for supplying an audio signal to a voice coil. However, in the speaker diaphragm according to the embodiment of the present invention, carbon fiber and entanglement are used. Since the fiber entangled body constituted by the fibers becomes a good conductive member as described above, at least a part of the conductive member can be replaced by the fiber entangled body.

FIG. 5 shows an example 100b of a speaker device in which a part of each of the two speaker lead wires 200 is replaced by a fiber entangled body 201 composed of carbon fibers and entanglement fibers (speaker device 100b). The portions other than the speaker diaphragm 1b and its audio signal supply line have the same configuration as the speaker device 100a described above, and thus detailed description thereof is omitted). The audio signal is transmitted from the speaker lead wire 200 to the fiber entangled body 201 of the speaker diaphragm 1b. After being transmitted to the vicinity of the voice coil 101 of the speaker diaphragm 1b by the fiber entangled body 201, the sound signal is transmitted to the fiber entangled body 201. It is transmitted to the voice coil 101 by a connected speaker lead wire (not shown).

FIG. 5 shows only the portion of the fiber entangled body of the speaker diaphragm that replaces the above-mentioned speaker lead wire. For example, on the side opposite to the side on which the two speaker lead wires are disposed, The fiber entangled body 201 can be provided in an area where the two speaker lead wires are not short-circuited, such as providing the fiber entangled body 201 composed of fibers and entangled fibers.

In the above example, both of the speaker lead wires are replaced with the fiber entangled body. However, only one speaker lead wire may be replaced with the fiber entangled body 201. . When four or more speaker lead wires are used, any one of the speaker lead wires can be replaced with the fiber entangled body 201.

FIG. 6 is an explanatory diagram showing an electronic device, an automobile, and a building on which the speaker device including the speaker diaphragm according to the embodiment of the present invention is mounted. A speaker device 100 according to an embodiment of the present invention includes an electronic device 200 (FIG. 6A), an automobile 300 (FIG. 6B), and a building 400 such as a house (FIG. 6C). )) Can be suitably mounted or installed.

An electronic device 200 as shown in FIG. 6A is a small electronic device such as a mobile phone or a personal digital assistant, or an electronic device such as a flat panel display or an audio device. Can be installed. In the automobile 300 as shown in FIG. 6B, the speaker device 100 can be mounted on the rear, front, door, ceiling, or the like of the vehicle interior. As the building 400 as shown in FIG. 6C, the speaker device 100 can be installed on an inner wall portion, a ceiling portion, a floor portion, an outer wall portion, or the like.

Although the present invention has been described with reference to the preferred embodiment, the speaker diaphragm and the speaker device of the present invention are not limited to the configuration of the above embodiment.

Those skilled in the art can appropriately modify the speaker diaphragm and the speaker device of the present invention in accordance with conventionally known knowledge. Of course, such modifications are also included in the scope of the present invention as long as the configuration of the speaker diaphragm and the speaker device of the present invention is provided.

100a, 100b Examples of speaker device according to the

present invention

1a, 1b Speaker diaphragm 100A Vibration surface 101 Voice coil 102 Magnetic circuit 102A Permanent magnet 102B Yoke 102C Plate 102G Magnetic gap 103 Frame 104 Voice coil support section 105 Edge 106 Damper 107 Center Cap 200 Lead wire for speaker

Claims

A speaker diaphragm comprising a fiber entangled body of carbon fiber and polyvinyl alcohol fiber having boron.
Comprising a plurality of layers composed of fiber entangled bodies,
2. The speaker diaphragm according to claim 1, wherein one of the plurality of layers is constituted by a fiber entangled body of the carbon fiber and a polyvinyl alcohol-based fiber having boron.
3. The speaker diaphragm according to claim 1, wherein the carbon fiber is longer than the polyvinyl alcohol fiber having boron.
The speaker diaphragm according to claim 1 or 2, wherein a melting temperature of the polyvinyl alcohol fiber having boron in water is higher than 80 ° C.
The speaker diaphragm according to claim 1 or 2, wherein the polyvinyl alcohol fiber having boron is a crimped fiber.
3. The speaker diaphragm according to claim 1, wherein a cross-sectional shape of the polyvinyl alcohol fiber having boron is circular or elliptical.
A speaker device comprising the speaker diaphragm according to claim 1, a frame, a voice coil, and a magnetic circuit.
The speaker device according to claim 7, wherein a fiber entangled body of the carbon fiber of the diaphragm and a polyvinyl alcohol-based fiber having boron electrically connects the voice coil and the outside. .
A conductive member for connecting the voice coil and the outside;
The diaphragm includes an insulating portion that insulates the carbon fiber and the conductive member;
The speaker device according to claim 8, wherein the conductive member is provided in the insulating portion.