JPH02111197A - Diaphragm for speaker - Google Patents

Abstract

PURPOSE:To obtain a diaphragm for speaker having a large bending rigidity and an inter-layer shearing strength by reinforcing a textile comprising high strength and high elastic modulus polyethylene fibers and glass fibers with a resin. CONSTITUTION:As threads constituting textile 1, blended yarns which are made by mixed spinning high strength and high elastic modulus polyethylene fibers and E glass fibers are used to weave a plane weave fabric whose weave density is 13 threads/inch for both weft and warp, a vinylester resin is subjected to prepleg processing, being heat press molded under the condition of 120 deg.C, 5 minutes and 5kg/cm<2> (face pressure) for one ply to obtain a cone diaphragm 3 for a 10 inch speaker. Thus, the bending rigidity is improved, resulting that the cone molding with as large as 10 inches is attained without causing deformation at the mold releasing. Moreover, an ideal piston motion is obtained up to a high frequency band in the acoustic characteristic and the sound quality at the high sound frequency range is excellent.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a diaphragm for a speaker.

[Conventional technology]

Conventionally, the diaphragm for this type of speaker was developed in 1987-1998.
As disclosed in Japanese Patent Publication No. 535, Japanese Patent Publication No. 59-198, and Japanese Patent Publication No. 52-52, it is known that the resin is reinforced with woven fabric.

Naturally, woven fabrics are impregnated with resin to form prepregs, which are then heated under pressure to obtain speaker diaphragms.

By the way, the performance required of a speaker diaphragm is to have the speed of sound V-(E/ρ)' (E: modulus of elasticity, ρ: density) as fast as possible, and an appropriate internal loss tan δ, and one more thing is dfl. layer 1 property and layer 111j shear strength IL S
One example is that S is large.

High-strength, recently replaced diaphragms for fiber speakers,
High elastic modulus polyethylene fibers i:(n), for example, Dyneema SK-60 (trade name, manufactured by Toyobo Co., Ltd.) and Techmilon (trade name, manufactured by Mitsui Ishiura Chemical Industries, Ltd.) have begun to be considered.

As shown in Table 1, this high-strength, high-modulus polyethylene fiber has a low specific gravity and high elastic modulus, so it does not exhibit a sound velocity comparable to that of carbon fiber. H1- has a characteristic that the sound quality in the high frequency range is extremely soft.

[Problem to be solved by the invention]

However, in the case of a speaker diaphragm made by reinforcing a resin such as epoxy resin or vinyl ester resin with a fabric made only of high-strength, high-modulus polyethylene fibers, since polyethylene is the raw material, it has poor adhesion to the resin.
The fabric and resin have poor integrity as a composite material, and as a result, they have low bending rigidity, which makes them susceptible to deformation during mold release, making molding especially large-diameter speaker diaphragms a national problem. In addition, the obtained diaphragm also tends to cause split vibration in the high frequency range due to lack of rigidity, causing problems in acoustic characteristics.Furthermore, the interlaminar shear strength (■■, SS) is low, so it is particularly difficult to use the NIBLY diaphragm. However, there is a disadvantage that the fiber and resin may separate due to vibration deformation, resulting in a decrease in the durability of the acoustic properties.

[Means to solve the problem]

The purpose of the present invention is to solve these disadvantages, and the gist of the present invention is to strengthen a resin with a woven fabric, and the woven fabric is made of high-strength, high-modulus polyethylene fibers and glass fibers. A speaker diaphragm characterized by being made of a woven fabric.

〔Example〕

FIG. 1 shows an embodiment of the speaker diaphragm of the present invention,
The speaker diaphragm 3 is obtained by reinforcing the resin 2 with the fabric I, and the fabric 1 is a fabric made of high-strength, high-modulus polyethylene fiber and glass fiber.

This speaker diaphragm has improved bending rigidity compared to speaker diaphragms made by reinforcing resin with polyethylene fiber fabric, and as a result does not cause shape distortion during mold release, and has a large diameter cone of 10 inches. Molding became possible.

In addition, the acoustic characteristics show ideal piston movement up to the high frequency range, and the sound quality in the high range is good.

Furthermore, since the interlaminar shear strength has been improved, it has become possible to mold NIBLY diaphragms, allowing for greater flexibility in model selection.

Here, the high strength, high modulus polyethylene fiber has a tensile strength l of at least 209/d, preferably 30 g/d or more.
It is recommended that i', u have a tensile modulus of at least 5009/d or more.

In addition, single fiber of high strength, high modulus polyethylene fiber: <M
There is no particular limitation on the denier, but it is preferably 0.
2d to 20d, more preferably 0.5d to 0 (I is preferable).

Furthermore, the total denier of the high-strength, high-modulus polyethylene fiber is preferably in the range of 300d to +600d.1. Yes, but
According to the bending rigidity of the obtained diaphragm, Hood ~ 1GQ
Od or Sara? This is desirable.

Further, the fiber structure is not particularly limited, such as plain weave, satin weave, etc., but a hand-woven structure is preferable from the viewpoint of decorative appearance.

Regarding glass fibers, there are No. 1 glass, S glass, etc. as glass fibers for FRP, but there is no particular limitation.

The mixing ratio of high-strength, high-modulus polyethylene fibers and glass fibers (1) is preferably in the range of 30 to 70 weight percent.

Here, if it is 30% or less, the polyethylene n K(ff
This is undesirable because it detracts from the high sound speed and lightness that are the characteristics of .

On the other hand, if it exceeds 70%, the efficiency of improving bending rigidity and interlaminar shear strength will be low and the objective will not be achieved.

The mixing method is not particularly limited, but it may be a method of using a mixed yarn of polyethylene fiber and glass fiber, or a method of using a drawn yarn for the warp and weft of the fabric, or a method of mixing both fibers for the warp and weft, respectively. Good.

Furthermore, it is desirable that the mixing ratio be equal for both the warp and the weft.

The matrix resin used in the present invention can be either a thermosetting resin or a thermoplastic resin, but it is preferably in the form of a liquid or a solution in order to impregnate the fabric.

From this point of view, epoxy resins, vinyl ester resins, and unsaturated polyethylene resins are often used.

The above configuration will be explained according to a specific example.

Example 1 High-strength, high-modulus polyethylene fiber (Toyobo Co., Ltd. trade name: Dyneema S) was used as the yarn constituting the textile 1.
A yarn containing about 67% by weight of polyethylene fiber (T-L) was obtained by blending E-glass fiber (Mt, ECG 751/0) with G-60,1200 denier/1170 filament.

A plain woven fabric with a weave density of 13 threads/inch was woven using the mixed yarn.

This fabric is processed with vinyl ester resin,
A 10-inch cone-shaped diaphragm 3 was obtained by heat-pressing molding at 5 ky/cm' below the surface for 5 minutes at 120° C. in an I-Bryer.

There was no shape or distortion of the cone.

Table 2 shows the physical properties of the diaphragm.

Example 2 The above polyethylene fiber of Practical Example 1 <&I 200 denier/+170 filament and E glass fiber ECG371
A plain woven fabric was obtained by alternately mixing I/I fibers at a weave density of 12 fibers/inch.

The content of the ren fiber was about 50% by weight.

Using this fabric, a 10-inch cone-shaped diaphragm was obtained according to Example 1.

There was no distortion of the cone shape at all.

Table 2 shows the tentative physical properties of the sample.

Comparative Example 1 Using the polyethylene fiber <tl l 200 denier/1170 filament of Example 1, a plain woven fabric with a weave density of at most 15 threads/inch was woven.

Using this fabric, a 10-inch cone-shaped diaphragm was obtained according to Example 1.

In this case, the cone was thermally deformed during mold release, and exhibited uneven distortion.

Table 2 shows the physical properties of the diaphragm.

The evaluation of Examples and Comparative Examples was conducted under the following conditions.

[Density] Determined by density gradient tube method.

[Monoulus] It was determined by the vibration reed method using an FRP flat plate (I-Bly).

[tan δ] According to the method for measuring modulus.

[Sound velocity] Calculated based on the following formula from density (δ) and modulus (E).

V=(E/δ)■ (z, sl F' RP with a thickness of 251 m was molded, and the shear stress was determined by the sheet J-beam method under the condition of (!/h=4) and calculated based on the following formula.

[Bending rigidity]

Here, P: shear stress (&g) A: Cross-sectional area of test piece (mu’) a: Rejection between fulcrums (m, v) h: Test piece P7-mi (zu) 1 piece of FRP temporary molded and 3 pieces A bending test was performed using the support method, and Find the flexural modulus based on the formula Ta.

Here, a rejection between the fulcrums (xx) W: Medium test piece (am) h: Test piece thickness (!1M) F/Y: lxx bending displacement Actual measurement of bending stress 1st shift (&l/πm) The bending conditions are tip radius (R) l■ Using a pressurizer, the distance between the fulcrums (0 was set to 10 mm.

Table 2 As is clear from Table 2, the sound velocity of the diaphragm based on the present invention is slightly lower than that of the conventional product.The tan δ of the diaphragm maintains almost the same height as the conventional product, and the bending rigidity has been improved. As a result, there was no distortion of the cone shape, and the sound quality in the high frequency range was stable without causing split vibration.

In addition, adhesion (ILSS) was greatly improved.

〔Effect of the invention〕

As described above, the present invention makes it possible to obtain a speaker diaphragm with greater bending rigidity and interlaminar shear strength than a speaker diaphragm made of a resin reinforced with a fabric made only of high-strength, high-modulus polyethylene fibers. Therefore, it is possible to suppress the separation of the fiber and resin due to the rising vibration of splitting vibrations, significantly improve the acoustic characteristics and durability, and also obtain a material with appropriate sound velocity and internal loss, and also obtain a product at a low cost. I can do it.

As described above, the intended purpose can be fully achieved.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a plan view. Violet...fabric, 2...resin.

Claims (1)

[Claims] 1. A speaker diaphragm made by reinforcing a resin with a woven fabric, the woven fabric being a woven fabric made of high-strength, high-modulus polyethylene fibers and glass fibers.