JP3142703B2 - Speaker diaphragm and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loudspeaker diaphragm for use in audio output equipment and the like and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, in the audio-related field,
With the digitization of reproduced music sources, speakers as sound output devices are required to have higher output sound pressure, lower distortion rate, and flatness characteristics than before. Also, there is a demand for higher quality of reproduced sound, and a diaphragm for a loudspeaker which influences acoustic characteristics is increasingly regarded as important. Particularly, in the case of speakers for PAs, studio monitors, and in-vehicle speakers, the operating conditions are severe.

[0003] From the viewpoint of the acoustic characteristics of a speaker, it is ideal that the speaker diaphragm performs a piston motion over the frequency band to be used. However, if the diaphragm is deformed during the vibration or divided vibration occurs, the sound pressure is reduced. -Frequency characteristics, distortion rate,
The phase characteristics and the like deteriorate, which hinders high-fidelity reproduction. Also, from the viewpoint of input resistance, the speaker diaphragm has sufficient strength against bending stress applied when the vibration system has a large amplitude and peeling force applied to a joint between the diaphragm and other components. If not, the diaphragm will be broken, especially at the time of large amplitude.

[0004]

DISCLOSURE OF THE INVENTION A paper pulp diaphragm often used as a conventional speaker diaphragm is: Since the material has a small E / ρ (where E: elastic modulus, ρ: density), the high-band resonance frequency is low, and the speaker cannot reproduce to a high frequency. 2. Due to low elastic modulus and low strength against bending stress,
Buckling occurs at high input. 3. Since the binding force between the pulp fibers constituting the material is weak and the peel strength in the surface thickness direction is weak, there is a defect that peel failure occurs in a layered manner at the bonding site.

The present invention has been made in view of such a conventional problem, and realizes a loudspeaker diaphragm having a high high-frequency resonance frequency without deformation of the diaphragm during vibration or occurrence of divided vibration. It is an object of the present invention to provide a speaker diaphragm excellent in formability.

[0006]

According to a first aspect of the present invention, an acrylic thermoplastic polymer resin is applied to the surface of a filament of a polyester resin as a core fiber to form a double-layered fiber. Characterized in that a woven fabric obtained from the fiber of (1) is formed into a diaphragm.

[0007] The invention of claim 2 of the present application is a core fiber.
An acrylic thermoplastic polymer resin is applied to the surface of a polyester resin filament to form a double layer fiber, and a nonwoven fabric obtained from the double layer fiber is formed into a diaphragm.

[0008] the invention of claim 3, according to claim 1, wherein
In the method of manufacturing a diaphragm for a speaker, when a woven fabric is formed into a diaphragm using a mold, the mold is heated to a predetermined temperature range, so that an acrylic thermoplastic coated on a polyester resin filament surface is heated. melting the only polymeric resin, by the woven fabric is cooled and solidified, characterized by forming the diaphragm to form a sandwich structure in the fabric. The invention according to claim 4 of the present application is a spin motor according to claim 2.
In the manufacturing method of the diaphragm for the
When molding into a diaphragm, heat the mold to a predetermined temperature range
By doing so, the polyester resin filament surface
Melts only the applied acrylic thermoplastic polymer resin
Then, the non-woven fabric is cooled and solidified,
Specially for forming a diaphragm with a sandwich structure.
Sign .

[0009]

According to the first or second aspect of the present invention having the above features.
According to the invention, since the thermoplastic polymer resin is applied to the surface of the core fiber, when the fiber is formed into a diaphragm, the binding force between the fibers is increased and the bending rigidity is improved. That is, by thermally melting the fibers at the time of molding, it is possible to densely fill the gap between the fibers constituting the woven fabric and the nonwoven fabric with the thermoplastic polymer resin, so that the bending rigidity is improved.
Furthermore, unlike the conventional method, in which the thermoplastic polymer resin is directly applied or impregnated to the surface of a woven or nonwoven fabric, the rigidity can be maintained with the minimum amount of resin, leaving sufficient internal friction between fibers. A diaphragm with a high internal loss is obtained.
For this reason, the divided vibration of the diaphragm hardly occurs.

Further, according to the third and fourth aspects of the present invention, when forming a woven or nonwoven fabric into a diaphragm, the molding conditions such as the heating temperature in the mold and the molding time are controlled within a predetermined range. By doing so, it is possible to set a desired value of the internal loss of the diaphragm and the apparent rigidity due to the sandwich structure. Therefore, a diaphragm having a high internal loss and an arbitrary shape can be easily manufactured.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A speaker diaphragm according to one embodiment of the present invention will be described below with respect to its material and a method of manufacturing the diaphragm. The speaker diaphragm in this embodiment is formed of a double-layered fiber in which a thermoplastic polymer resin is applied to the surface of a filament serving as a core fiber. For example, a polyester resin is used as the core fiber, and an acrylic resin is used as the thermoplastic polymer resin. The acrylic resin is uniformly applied immediately after the polyester resin is converted into fibers, and after drying, becomes a fiber material constituting a woven or nonwoven fabric. The smaller the fiber diameter is, the more rigid the multifilament becomes.
Those having a size of 0 micron or less were used. The non-woven fabric is typically produced by an air dispersion method using a single fiber or a spun bond method. The woven fabric includes plain weave, twill weave, and three-way weave. The use of fibers as the diaphragm and the fact that the fibers are in a double layer greatly affect the physical properties of the diaphragm,
The secondary factor, weaving, is not specified.

Next, a mold having a shaping surface in the shape of a diaphragm is prepared, and a woven material or a nonwoven material is loaded into the mold.
Then, the mold is heated to a temperature equal to or higher than the softening point of the thermoplastic polymer resin. This melts the thermoplastic polymer resin,
The fibers enter the gaps between the core fibers, and the filaments or the yarns (multifilaments) are joined to each other.

Next, when the mold is cooled, the core fiber and the thermoplastic polymer resin are cured, and the woven or nonwoven fabric is formed into a diaphragm having a predetermined shape. This 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, whereby a speaker is assembled.

The operation of the speaker having such a configuration will be briefly described. Vibration systems such as a diaphragm, a voice coil bobbin, and a voice coil are driven by a magnetic circuit system including a magnet, a pole, a plate, and a yoke to make a piston movement. That is, when a voice current flows through a voice coil in a uniform magnetic field, a vertical electromagnetic force is generated in the voice coil, and the voice coil vibrates according to the current. Sound waves are emitted by properly transmitting this vibration to the diaphragm.

When a woven or nonwoven material is heated and melted in a mold so that only the thermoplastic polymer resin applied to the polyester fiber is melted, the diaphragm obtained by cooling and solidification has a rigidity with respect to a reference mass. Will be excellent. Representative physical properties of the conventional paper diaphragm and the diaphragm of this embodiment are as follows. Here, the Young's modulus of the material is E, the apparent specific gravity is ρ, the sound speed is c, and the internal loss δ.

By using such ultra-fine fibers, the rigidity of the woven or nonwoven fabric itself is improved. In addition, the voids formed between the fibers reduced the areal density or apparent specific gravity, so that the rigidity due to the thickness could be increased. Therefore, when the diaphragm is vibrated by the voice coil, deformation and split resonance of the diaphragm do not occur, and good acoustic characteristics can be obtained. Specifically, the distortion rate can be reduced by 20 dB as compared with a paper cone diaphragm having the same shape. Further, the high-band resonance frequency could be increased from 8 kHz to 11 kHz. In addition, due to the improvement of the internal loss, the peak dip of the output sound pressure is about ± 3dB compared to the conventional paper cone diaphragm.
Could be lowered.

[0017]

As described above, according to the present invention, the polyester
A woven or non-woven material is made using a double-layered fiber coated with an acrylic thermoplastic polymer resin on the surface of a core fiber made of a tellurium resin, and the woven or non-woven material is heated in a mold. Melts and cools and solidifies to form a sandwich structure
The speaker diaphragm to be formed is formed. Therefore, a speaker having a low distortion rate, a high high-band resonance frequency, and a high input resistance can be obtained while the molding process is simple. Further, the divided vibration of the diaphragm is hardly generated, and the peak dip at the vibration frequency is reduced. For this reason, a speaker with good acoustic characteristics and sound quality and excellent reliability for large amplitude can be realized.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04R 7/02 D04H 1/54 H04R 31/00 D06M 15/00

Claims (4)

(57) [Claims] An acrylic thermoplastic polymer resin is applied to the surface of a polyester resin as a core fiber to form a double-layered fiber, which is obtained from the double-layered fiber.
A diaphragm for a speaker, wherein a woven fabric is formed into the diaphragm. 2. A double-layer fiber obtained by applying an acrylic thermoplastic polymer resin to a filament surface of a polyester resin serving as a core fiber, and obtained from the double-layer fiber.
A diaphragm for a speaker, wherein a nonwoven fabric is formed into the diaphragm. 3. When the woven fabric is formed into a diaphragm using a mold, the woven fabric is heated to a predetermined temperature range to be applied to the polyester resin filament surface.
Melted only thermoplastic polymer resin of the acrylic, by cooling and solidifying the fabric, speaker of claim 1, wherein the forming the diaphragm to form a sandwich structure with the fabric Manufacturing method of diaphragm. 4. The nonwoven fabric is formed into a diaphragm using a mold.
In this case, the mold is heated to a predetermined temperature range.
And applied to the polyester resin filament surface
Melts only acrylic thermoplastic polymer resin, By cooling and solidifying the nonwoven, the nonwoven
A diaphragm with a sandwich structure formed on it
3. The method of manufacturing a speaker diaphragm according to claim 2, wherein
Law.