JPS63167600A - Diaphgragm for speaker - Google Patents

Abstract

PURPOSE:To obtain a diaphragm for speaker having a high resonance frequency with small distortion rate by heating and forming a mixture of cardol and anacardic acid and pulp impregnated with an impregnant being the condensated carbolic acid by aldehyde. CONSTITUTION:After craft pulp with METSUKE 25g/m<2> is impregnated in a mixed liquid in the B-stage state being the mixture of the cardol and anacardic acid and the condensated carbolic acid by aldehyde, the compound is heated and formed to form a dome shaped diaphragm. The diaphragm is fixed to a voice coil bobbin. The speaker using the diaphragm has an excellent acoustic characteristic without deformation of diaphragm and split resonance and the distortion factor is reduced. Moreover, the high resonance frequency is increased from 21kHz to 29kHz. Furthermore, the acoustic output is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a speaker diaphragm used in acoustic output equipment and the like.

Conventional technology In recent years, in the cassette tape recorder, micro cassette tape recorder, and high-fidelity stereo industries, there has been a demand for speakers with better output sound pressure, distortion rate, and flatness than before in terms of the acoustic characteristics of speakers used as audio output equipment. Speaker diaphragms, which influence acoustic characteristics, are becoming increasingly important.

Hereinafter, the operation of the example of the above-mentioned conventional speaker will be explained. A speaker consists of a vibration system such as a diaphragm, a voice coil bobbin, and a voice coil, and a magnetic circuit system (not shown) that includes a magnet, a pole, a plate, and a yoke.

When an audio current flows through a voice coil in a uniform magnetic field, a vertical electromagnetic force is generated in the voice coil, causing it to vibrate in response to the current. This vibration is transmitted correctly to the vibration of the diaphragm and is emitted as a sound wave (for example, Toshio Hayasaka, Introduction to Acoustic Engineering, Nikkan Kogyo Shimbun).

Problems to be Solved by the Invention However, ideally, the diaphragm of a speaker should make a piston movement over the frequency band used, but if the diaphragm deforms during vibration or split vibration occurs, the sound pressure-frequency characteristics will deteriorate. , distortion rate 1 phase characteristics, etc. deteriorate, which impedes high-fidelity reproduction. In addition, conventional paper cone diaphragms and plastic diaphragms have a low high-frequency resonance frequency because the diaphragm material has a small X/ρ (E: elastic modulus, p: density).
The drawback was that the speakers could not reproduce high frequencies.

In view of the above-mentioned problems, the present invention provides a diaphragm for a speaker that does not deform or cause split vibration during vibration and has a high high resonance frequency.

In order to achieve this object, the speaker diaphragm of the present invention is impregnated with a mixture of cardles, anacardic acid, and a B-stage mixture of carbonic acid co-condensed with aldehyde. A molded product made by heating and molding pulp is used as a diaphragm.

Function The molded article of the present invention uses a mixture of cardol and anacardic acid, and a phenolic impregnating agent made by co-condensing carbolic acid with aldehyde, so it has a very high modulus of elasticity.
When this is used as a diaphragm, the diaphragm has a very high bending rigidity, so the diaphragm does not deform during vibration and no split resonance occurs. In addition, since kraft pulp is used as the base material and is impregnated with the above-mentioned impregnating agent, the specific elastic modulus E/ρ
(However, E: elastic modulus, ρ: density) is large, and when used as a diaphragm, the reproduction band of the speaker will be extended, making it possible to obtain a speaker with excellent sound pressure-frequency characteristics, distortion rate, and phase characteristics. can.

In addition, this diaphragm material uses a mixture of cardol and anacardic acid, and a phenol-based impregnating agent made by co-condensing carbolic acid with aldehyde, so it has excellent solvent resistance, water resistance, and heat resistance. Withstands use of the speaker under harsh conditions.

EXAMPLE A speaker diaphragm according to an example of the present invention will be described below.

A speaker according to an embodiment of the present invention includes a diaphragm formed by heating and molding pulp impregnated with a mixture of cardol and anacardic acid and a B-stage liquid mixture obtained by co-condensing carbolic acid with aldehyde. I am using it. This diaphragm is fixed to a voice coil bobbin, and the voice coil provided at the tip of the voice coil bobbin is inserted into a magnetic gap (not shown) of a magnetic circuit.

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

The speaker consists of a vibrating body such as a diaphragm, a voice coil bobbin, and a voice coil, and a magnetic circuit system (not shown) consisting of a magnet, a pole, a plate, and a yoke. When an audio current flows through a voice coil in a uniform magnetic field, a vertical electromagnetic force is generated in the voice coil, causing it to vibrate in response to the current. This vibration is properly transmitted to the vibration of the diaphragm and emitted as a sound wave.

Next, to explain in detail the manufacturing method of the diaphragm, a mixture of cardol and anacardic acid and monocarboxylic acid are co-condensed with aldehyde in a B-stage state mixed solution with a basis weight of 25g/
- After being impregnated with kraft pulp, it is heated and molded to form a dome-shaped diaphragm with a diameter of 28 m5+ and a basis weight of 30 g/-.

As described above, according to this example, a mixture of cardol and anacardic acid and B-
The speaker uses a diaphragm made by heating and molding pulp impregnated with the mixed liquid in the stage state, and provides good acoustic characteristics without deformation of the diaphragm or split resonance. 26 d strain rate compared to the plate
B can be lowered. Also, the high resonance frequency is 2
It was possible to raise the frequency from 1KHz to 29KHz.

Furthermore, the peak dip of the output sound pressure can be reduced by about 3 dB, which is ±3 dB, compared to an aluminum diaphragm.

Effects of the Invention As described above, the present invention heats pulp impregnated with a mixture of cardol and anacardic acid and a B-stage mixture of carbolic acid co-condensed with aldehyde, and vibrates the molded product. When used as a plate, it is possible to obtain a speaker with a low distortion rate, a high high-frequency resonance frequency, and a large acoustic output, and it is possible to realize an excellent speaker with good acoustic characteristics.

Claims (1)

[Claims] A diaphragm for a speaker, characterized in that it uses a molded product obtained by heating and molding pulp impregnated with a mixture of cardol and anacardic acid, and a B-stage liquid mixture obtained by co-condensing carbolic acid with aldehyde.