JPH06165289A - Diaphragm for speaker and its manufacture - Google Patents

Abstract

PURPOSE:To obtain excellent sound pressure versus frequency characteristic, distortion ratio and phase characteristic and to simplify the forming process by forming a 3-dimensional textile or a multiple textile among textiles blended with carbon fibers, thermoplastic resins and threads to be a prescribed shape. CONSTITUTION:Carbon fibers are used for weft 1 and carbon fibers and polycarbonate fibers are used for a warp 2 as textile and they are woven in 3-dimensional way. The textile is inserted in a metallic die with a heater and a cooler, after the polycarbonate fibers are molten and formed, the fibers are cooled while keeping a press pressure. Then the metallic die is open and the forming is extracted. Since the material has a high elastic modulus the bending rigidity of the diaphragm is very high by using the material for the diaphragm and deformation of the diaphragm or production of split vibration during vibration is very less. Since the specific elastic modulus is large in the forming made of the 3-dimension textile or multiple textile in a prescribed shape, the high resonance frequency is high and the reproduction band of a speaker is extended toward high frequencies and a signal up to a high frequency is reproduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker diaphragm used for an acoustic output device and the like, and a method for manufacturing the diaphragm.

[0002]

2. Description of the Related Art Recently, in the audio industry,
With the digitization of reproduced music sources, the speaker as an acoustic output device is required to have output sound pressure, distortion rate, and flatness more than ever before in its characteristics, and it is desired to improve the reproduced sound quality. Speaker diaphragms, which influence the acoustic characteristics, are becoming more and more important.

In addition, especially for PA, studio monitor,
In-vehicle speakers are used under severe conditions, and particularly when a large input is applied, appropriate strength for the diaphragm is required according to the amplitude amount of the vibration system.

From the viewpoint of the acoustic characteristics of the speaker, it is ideal that the diaphragm for the speaker makes a piston motion over the frequency band to be used, but if the diaphragm is deformed during vibration or divided vibration occurs, the sound pressure is reduced. -Frequency characteristics, distortion factor,
The phase characteristics are deteriorated, which hinders high fidelity reproduction.

From the viewpoint of input resistance, the speaker diaphragm has sufficient strength against bending stress applied when the vibration system vibrates and peeling force applied to the joint between the diaphragm and other parts. If it is not done, it will be destroyed especially when the amplitude is large.

In the paper cone diaphragm that has been widely used in the past, the material has a small E / ρ (E: elastic modulus, ρ: density), so that the high resonance frequency is low and the speaker reproduces up to high frequencies. There was a drawback that I could not.

Further, since the paper material has a low elastic modulus and a low strength against bending stress, it causes buckling at the time of a large input, and the binding force between pulp fibers constituting the material is low, resulting in peeling in the thickness direction. Since the strength is low, there is a drawback that peeling failure occurs in layers at the bonding site.

[0008]

Therefore, conventionally, in place of such a paper diaphragm, an inorganic fiber such as carbon fiber or glass fiber, or a highly crystalline and highly heat-resistant organic fiber such as aramid fiber is used alone. Woven woven fabric or mixed woven fabric is impregnated with a thermosetting or thermoplastic resin binder,
A diaphragm that has been formed into a predetermined shape by a heating press using male and female dies has been used.

However, in forming such a conventionally used woven fabric, since a two-dimensional planar woven fabric is used as the woven fabric of the raw material, misalignment occurs during the forming to make the formed product inhomogeneous and sometimes bent. There is an inconvenience that the rigidity is directional. When this is used as a diaphragm, if it causes split resonance or if the misalignment is large, the resin binder cannot fully fill the gaps in the weave, creating voids, which hinders the function of the diaphragm. There was a problem that it would occur.

When a diaphragm having a large surface thickness is formed, a thick fabric woven with thick threads is used, or
A method has been taken in which thin fabrics are laminated to a desired thickness and formed. However, according to the former method, as the thickness of the fabric increases, the stretchability of the fabric decreases and molding is difficult, and at the same time, in the details, the fitting property of the fabric material to the mold shape is poor, and a desired shape is formed. Has many difficulties,
In addition, there is a problem that voids are easily formed in the molded product due to the large space between the textures.

On the other hand, according to the latter method, the formability is better than that of the former method, but since the bond strength between the layers of the laminated fabrics is relatively low, delamination occurs due to bending stress, and the thick layer is thick. There was a problem that the strength as a vibration plate was weaker than when using the woven fabric.

Further, conventionally, when a thermosetting resin is used as a binder, a step of forming a prepreg for forming a semi-cured material by impregnating a liquid resin is required. During this period, low temperature storage is required to suppress the curing reaction, and there is a problem that material management is troublesome.

Also, when a thermoplastic resin is used as a binder, a woven fabric and a thermoplastic resin film serving as a binder are superposed and inserted into a mold, and the binder resin is melt-impregnated by hot pressing to perform molding. Alternatively, a woven fabric and a thermoplastic resin film serving as a binder are stacked in advance and heated with a hot plate to melt and impregnate the binder resin, and the sheet-shaped prepreg is hot-pressed with a molding die to form a predetermined diaphragm shape. In any case, in order to secure the rigidity of the diaphragm in any case, if a binder with a high elastic modulus at room temperature, that is, a resin with a high heat deformation temperature is used, the shape of the mold during diaphragm formation is Fits poorly, cracks in the binder resin film and prepreg easily occur, and it is difficult to obtain a uniform diaphragm. There is a problem that the condition management of the heat press is very difficult.

The present invention solves the above-mentioned various problems of the related art. The vibration plate is not deformed during vibration or split vibration is not generated, the high resonance frequency is high, the sound pressure-frequency characteristic, the distortion rate, and the phase. It is an object of the present invention to provide a speaker diaphragm having excellent characteristics, high input resistance, excellent moldability, and capable of simplifying the molding process.

[0015]

DISCLOSURE OF THE INVENTION The present invention is a three-dimensional woven fabric among woven fabrics of carbon fiber, thermoplastic resin fiber or yarn,
It is formed by molding a multiple woven fabric into a predetermined shape.

Further, the present invention is a method for forming a predetermined shape by heating and melting thermoplastic resin fibers or threads in a mold, impregnating the carbon fibers, and then cooling and solidifying.

[0017]

According to the present invention, the misalignment at the time of molding is extremely small, the molded product is homogeneous, the directionality does not occur in the rigidity, and the split resonance occurs during use, as compared with the structure using the two-dimensional sheet fabric. Does not occur.

Further, since the misalignment is extremely small, the number of voids formed in the molded product is extremely small.

Further, since the above-mentioned material has a high elastic modulus, when this material is used as the diaphragm, the bending rigidity of the diaphragm is very large, and the diaphragm is deformed or divided vibration occurs during vibration. Very few.

Among the mixed fabrics of carbon fibers, thermoplastic resin fibers or yarns, three-dimensional fabrics or multi-layered fabrics are molded into a predetermined shape, which has a specific elastic modulus E / ρ (E: elasticity Ratio, ρ: density) is high, the high-frequency resonance frequency is high, the reproduction band of the speaker extends to the high frequency side, and it is possible to reproduce up to the high frequency range. You can get a speaker that you have.

Further, among the mixed woven fabrics of carbon fibers, thermoplastic resin fibers or yarns, the three-dimensional woven fabric or the multiple woven fabric formed into a predetermined shape has a high elastic modulus of the material and therefore has a high strength against bending stress. Since it is high and has a high strength against peeling force in the surface thickness direction, buckling does not occur at the time of a large input, and peeling failure does not occur in layers at the bonding site.

Further, since the thermoplastic resin fibers constituting the woven fabric are used as a binder, it is not necessary to prepare a prepreg in advance for molding, and the prepreg can be directly inserted into a molding die for molding, and a thermosetting resin can be used. Since it does not need to be stored at low temperature like the prepreg used,
The molding process is simple and at the same time material management is extremely easy.

On the other hand, the three-dimensional woven fabric and the multiple woven fabric can be woven into a thick fabric by changing the weaving structure, so that even a thick woven fabric has a close mesh spacing and a large stretchability. When the diaphragm having a large surface thickness is formed, the woven material has a good fit to the mold shape, and it becomes easy to mold a desired shape in detail.

In addition, since the weaving thread passes through the front and back sides in the thickness direction as well, the strength against bending stress is higher than that of a diaphragm formed by laminating thin fabrics, which causes delamination failure. It is possible to obtain a diaphragm of extremely high strength.

[0025]

Embodiments of the present invention will be described below with reference to the drawings.

In the speaker diaphragm of this embodiment, a multiple woven fabric obtained by interweaving carbon fibers and thermoplastic resin fibers is pressed and held in a mold, and the thermoplastic resin fibers are heated and melted to impregnate the carbon fibers. It is formed into a predetermined shape by cooling and solidifying. Although not shown, this speaker diaphragm is fixed to a voice coil bobbin, and a voice coil provided at the tip of the voice coil bobbin is inserted into a magnetic gap of a magnetic circuit to form a speaker.

The operation of the speaker configured as described above will be described below.

The speaker is composed of a vibration system such as a diaphragm, a voice coil bobbin, and a voice coil, and a magnetic circuit system including a magnet, a pole, a plate, and a yoke. When a voice current flows in a voice coil in a uniform magnetic field, an up-and-down electromagnetic force is generated in the voice coil and vibrates according to the current, and this vibration is accurately transmitted to the diaphragm and is transmitted as a sound wave to the outside. Is released.

Next, a method of manufacturing the speaker diaphragm of this embodiment will be described. As a material woven fabric, carbon fiber (1k) is used for weft, carbon fiber (1k) and polycarbonate fiber (900d) are used for warp, weft is 40 yarns / inch, warp yarn is 37.5 yarns / inch, and thickness is 240 μm. Weave into the structure. FIG. 1 shows a view of the woven structure thus woven, as seen from the cross-sectional direction. In FIG. 1, 1 is a weft and 2 is a warp.

This woven fabric was inserted into a mold equipped with a heating and cooling device, the mold temperature was 200 ° C., and the pressing pressure was 200 kg /
After melt-molding the polycarbonate fiber for about 3 minutes at cm 2, it is cooled to around 50 ° C while maintaining the pressing pressure. After that, the mold is opened and the molded product is taken out.

The physical properties of this molded product are shown in (Table 1).

[0032]

[Table 1]

In (Table 1), the multiple woven fabric molded article shows the same elastic modulus in the weft direction, the warp direction, and the three directions of the weft and the warp intersecting with each other at 45 °. Occasionally, no misalignment occurs and a molded product with uniform physical properties is completed, the molded product is homogenous, the directionality of rigidity does not occur, and this diaphragm shows that split resonance is extremely difficult to occur. .

Further, the elastic modulus is about 5 times and the tensile strength is about 4 times higher than that of the pulp paper-molded product, and the flexural rigidity of the molded diaphragm is very large and the diaphragm is deformed during vibration. In addition, it is extremely unlikely that split vibration occurs, and the strength against peeling force in the surface thickness direction is high, so that it is difficult to cause buckling at the time of a large input or to cause peeling breakage in a layered manner at the bonding site.

Also, in a speaker with a 14 cm aperture,
When using the diaphragm molded under the above conditions according to this example, good acoustic characteristics are obtained without deformation of the diaphragm and division vibration, as compared with the case where the diaphragm of the pulp paper-molded product having the same shape is used. At the high limit frequency from 20 kHz to 2
The reproduction frequency band of 6 kHz could be expanded to 6 kHz, and the distortion factor could be reduced by 23 dB. Furthermore, the peaks and valleys of the sound pressure-frequency characteristics were ± 3 dB, which was about 3 dB lower than that of the diaphragm using the pulp paper-molded product.

In this embodiment, the thermoplastic resin fiber is used only for the warp, but it may be used for the weft only or both the warp and the weft. Further, although the polycarbonate fiber is used as the thermoplastic resin fiber, depending on the desired physical properties of the vibration plate and other various properties, it has thermoplasticity such as polyester fiber, polyamide fiber, polyolefin fiber, polyphenylene sulphite fiber, polyether ether ketone fiber, etc. Any fiber will do.

In the woven structure as well, in order to realize the desired surface thickness of the diaphragm and the fitting property to the mold at the time of molding according to the shape of the diaphragm, an appropriate multiple structure, if necessary,
A three-dimensional structure may be used, and the structure is not limited to this example.

Another example of the woven structure is shown in FIGS. 2 and 3. Figure 2
Are various examples of the weave design of multiple woven fabrics, and FIG. 3 shows an example of the weave design of a three-dimensional woven fabric (a woven fabric having warps in the vertical direction).

The mixed woven fabric in the present invention refers to a woven fabric in which carbon fibers and thermoplastic resin fibers or yarns are mixed in a spinning process and a process equivalent thereto, and as a mixing method, mixed spinning, mixed twisting, mixed woven, etc. Is common, but is not limited thereto.

[0040]

As is apparent from the above description,
INDUSTRIAL APPLICABILITY The present invention realizes a diaphragm having a simple molding process and extremely easy material management before molding.

Further, it is possible to obtain a speaker having a small distortion, a high high-frequency resonance frequency, and a high input resistance, whereby a speaker having good acoustic characteristics, sound quality and high reliability can be realized. .

[Brief description of drawings]

FIG. 1 is a diagram of a weave design of a speaker diaphragm according to an embodiment of the present invention.

FIG. 2 is a diagram showing a weave structure of a multiple woven fabric of a speaker diaphragm according to an embodiment of the present invention.

FIG. 3 is a diagram showing a weave design of a three-dimensional woven fabric of a speaker diaphragm according to an embodiment of the present invention.

[Explanation of symbols]

 1 weft 2 warp

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhiro Inoue 3-2-6 Bingo-cho, Chuo-ku, Osaka City, Osaka Prefecture Shikishima Spinning Co., Ltd. (72) Inventor Hirohiko Terada 3 Bingo-cho, Chuo-ku, Osaka City, Osaka Prefecture -2-6 Shikishima Spinning Co., Ltd. (72) Inventor Keigo Noma 3 Bingo-cho, Chuo-ku, Osaka-shi, Osaka 2-6 Shikishima Spinning Co., Ltd. (72) Inventor Tomoyuki Fukada Bingo, Chuo-ku, Osaka-shi, Osaka 3-2-6 Shikijima Spinning Co., Ltd. (72) Inventor Kazutada Yamato 3-2-6 Bingo Town, Chuo-ku, Osaka City, Osaka Prefecture (72) Inventor Ryoichi Okamoto Osaka Prefecture Osaka Shikishima Spinning Co., Ltd. 3-2-6 Bingo-cho, Chuo-ku, Yokohama-shi

Claims (2)

[Claims] 1. A diaphragm for a speaker, comprising a three-dimensional woven fabric or a multiple woven fabric of a mixed woven fabric of carbon fibers, thermoplastic resin fibers or yarns, which is molded into a predetermined shape. 2. The thermoplastic resin fiber or thread is heated and melted in a mold, impregnated into the carbon fiber, and then cooled and solidified to be molded into a predetermined shape. Manufacturing method of diaphragm for speaker.