JPH0614389A - Diaphragm for loudspeaker - Google Patents

Abstract

PURPOSE:To suppress and vary an abnormal split vibration mode of the diaphragm, to have an abnormal vibration suppressing work in a high frequency band, and to improve a frequency characteristic of the loudspeaker by constituting the diaphragm of a high elasticity fiber and a thermosetting resin for fixing it and holding a shape, and using a specific epoxy resin for this thermosetting resin. CONSTITUTION:The diaphragm consists of a high elasticity fiber and a thermosetting resin for fixing it and holding a shape, and the thermosetting resin is an epoxy resin which is mainly composed of butyl acrylate, and denatured by reactive elastomer having an epoxy group in a side chain. Also, it is desirable that this thermosetting resin is an epoxy resin denatured by a ternary copolymer in which butyl acrylate, vinyl benzyl glycizyl ether and styrene are in a mole ratio of a range of 62:22:16 to 74:17:10, respectively. A full line and a dotted line in the figure show a characteristic of a loudspeaker using an embodiment diaphragm, and the case of a conventional one, respectively, and in a band of >=2kHz, a frequency characteristic of the embodiment shows a smooth characteristic in which a peak and a dip scarcely occur.

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 in various audio equipment, and more particularly to a diaphragm in which a fibrous base material is formed of synthetic resin.

[0002]

2. Description of the Related Art As is well known, a diaphragm of a speaker is generally a diaphragm of a soft dome except for a special one such as a soft dome diaphragm in order to suppress the vibration because it causes distortion and noise of reproduced sound. High elasticity and high internal loss are required, and those obtained by making fibers such as pulp and pressing them, those obtained by impregnating fibrous material with resin as a shaping material, metals, synthetic resins, and laminates thereof are used. However,

[0003]

In the conventional hard diaphragm having the above-mentioned structure, for example, in the case where a high-rigidity fibrous material is impregnated with a resin as a shaping material, the rigidity is, for example, carbon as a fibrous material. Satisfactory values are obtained by using fibers, but if polypropylene or the like with large internal loss is used as a shaping material, there is a problem in the assembly process due to lack of adhesion,
Considering the position as a product, it is difficult to maintain a good balance between rigidity and mechanical internal loss in either case, and there are many problems that need to be solved, such as unnatural reproduced sound in many speakers. It was

Therefore, the present invention solves the above-mentioned drawbacks of the conventional example, has a high rigidity and a vibration energy absorption capability, extends the reproduction frequency range, and suppresses abnormal vibration even in a high range. An object of the present invention is to provide a speaker having excellent quality, which has a reproduced sound with little distortion and a flat frequency characteristic by obtaining a diaphragm having the same.

[0005]

The first invention of the present application for achieving the above object comprises a high-elasticity fiber and a thermosetting resin that fixes the high-elasticity fiber and retains its shape. A diaphragm for a loudspeaker, characterized in that the functional resin is an epoxy resin modified mainly with butyl acrylate (hereinafter abbreviated as BA) and having a side chain with an epoxy group, and a second diaphragm. Consists of a high elastic fiber and a thermosetting resin that holds the shape by fixing the high elastic fiber, and the thermosetting resin is BA, vinylbenzyl glycidyl ether (abbreviated as VBGE) and styrene (abbreviated as St). Is a epoxy resin modified with a terpolymer having a molar ratio in the range of 62:22:16 to 73:17:10, respectively.

[0006]

By modifying the epoxy resin with a reactive elastomer having an epoxy group on the side chain as in the above BA, flexibility and high toughness can be imparted to the epoxy resin. By using a flexible and high toughness modified epoxy resin as a shaping material for the base material of high rigidity fiber, both the Young's modulus and internal loss of the vibration plate as a vibration system component are increased, resulting in high rigidity and vibration. It has the ability to absorb energy and also has the effect of suppressing abnormal vibrations such as a vibration plate, improving the frequency characteristics in the mid-high range, and also improving the adhesion to other components that make up the vibration type. Workability will be significantly improved.

[0007]

EXAMPLE A reactive elastomer composed of a terpolymer (the molecular structure of which is shown in FIG. 1) having a molar ratio of BA: VBGE: St of 62:22:16 was prepared and used as a general bisphenol A type epoxy resin. Mix at the ratio of 30wt%, 110 ℃
The reaction was carried out with stirring to obtain the target modified epoxy resin.

A PAN-type carbon fiber non-woven fabric (basis weight: 30 g) was impregnated with the above modified epoxy resin and molded at a temperature of 160 ° C., a pressing pressure of 5 kg / cm ² , and a pressing time of 15 minutes to obtain a vibration plate and a test flat plate sample. It was

As a conventional example for comparison, the same PAN type carbon fiber non-woven fabric (basis weight: 30 g) is impregnated with bisphenol A type epoxy resin, the temperature is 160 ° C., the pressing pressure is 5 kg /
It was molded at cm ² and a pressing time of 15 minutes to obtain a vibration plate and a test flat plate sample.

The Young's modulus E, internal loss (tan δ) and density of the test flat plate samples of these examples and the conventional example were measured and shown in FIG.

Further, the molar ratio of BA, VBGE, St in the reactive elastomer composed of the above terpolymer, and the mixing ratio of the reactive elastomer and the bisphenol A type epoxy resin in the modified epoxy resin of the present invention. The change in the fracture toughness value when V is changed is shown in the graph of FIG. This result shows that the molar ratio of BA, VBGE, and St is BA: VB.
It is clear that the fracture toughness is good when GE: St is in the range of 62:22:16 to 73:17:10 and the mixing ratio of the reactive elastomer to the bisphenol A type epoxy resin is 25% or more. is there.

FIG. 4 shows frequency characteristics when the above-described diaphragm of the embodiment and the diaphragm of the conventional example are applied to a speaker. In FIG. 4, the solid line shows the characteristics of the speaker using the diaphragm of the embodiment, and the dotted line shows the characteristics of the speaker using the diaphragm of the conventional example. When the two are compared, the frequency characteristics of the embodiment peak in the band of 2 KHz or more. , Has a smooth characteristic with little dip, and shows the characteristics predicted from the physical property values shown in FIG. 2 in the base material.

The speaker diaphragm according to the present invention and the method for manufacturing the speaker diaphragm have been described in detail above with reference to typical examples. The diaphragm according to the present invention and the types of raw materials such as polyols and polyisocyanates, In addition, the embodiment of the manufacturing method is not limited to the structure of the above-mentioned embodiment, and has the constituents described in the above-mentioned claims, exhibits the action referred to in the present invention, and has the effects described below. As long as it is possible, it can be appropriately modified and implemented.

[0014]

[Effect] The speaker diaphragm according to the present invention has the following effects.

The diaphragm of the present application uses high-rigidity fibers as the base material, and the epoxy resin as the shaping material is modified to impart flexibility and high toughness. The Young's modulus and the internal loss are both large, and the high rigidity and the vibration energy absorbing ability suppress and change the abnormal divided vibration mode of the diaphragm, thereby improving the frequency characteristic in the high frequency range as shown in FIG. Therefore, it is possible to inexpensively provide a speaker with excellent quality having a reproduced sound with little distortion and a flat frequency characteristic.

[Brief description of drawings]

FIG. 1 is a molecular structure diagram of a reactive elastomer of the present invention.

FIG. 2 is a comparison diagram of material property values of an example and a conventional example.

FIG. 3 is a characteristic diagram showing a practical range of the reactive elastomer of the example.

FIG. 4 is a frequency characteristic diagram of a speaker using the diaphragm of the example and the conventional example.

Claims (2)

[Claims] 1. A thermosetting resin comprising a high elastic fiber and a thermosetting resin for fixing the high elastic fiber to retain its shape, the thermosetting resin comprising butyl acrylate (hereinafter abbreviated as BA) as a main chain. A speaker diaphragm, which is an epoxy resin modified with a reactive elastomer having an epoxy group. 2. A high-elasticity fiber and a thermosetting resin that fixes the high-elasticity fiber and retains its shape, wherein the thermosetting resin is BA and vinylbenzyl glycidyl ether (VB).
62 and styrene (abbreviated as GE) and styrene (abbreviated as St), respectively:
A speaker diaphragm, which is an epoxy resin modified with a terpolymer having a molar ratio in the range of 22:16 to 73:17:10.