JPH01200900A - Speaker diaphragm and its manufacture - Google Patents

Abstract

PURPOSE:To simplify a production process by integrating a vacuum formed thermoplastic sheet with an injection molded resin by fusing. CONSTITUTION:When the molding of the sheet 11 is completed, a male mold 6a and a female mold 6b are contacted to inject the molten resin 12 from a gate 10, when the resin 12 is filled in a cavity 5, a metal mold is cooled to solidify the resin 12. According to the injection molding of this resin 12, it is fused to the sheet 11, integrated to have a composite material. In such a way, a diaphragm 4 is formed by taking out the diaphragm 4 in which the resin 12 is solidified from the metal mold through the operations of separating the male mold 6a and the female mold 6b, removing the gate 10 and cutting the external periphery of the edge of the sheet.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a voice coil inserted into a magnetic gap formed in a magnetic circuit of a speaker, and a voice coil generated by a signal current flowing through the voice coil. The present invention relates to a speaker diaphragm for transmitting vibrations and propagating the vibrations in the air, and a method for manufacturing the same.

[Conventional technology]

Traditionally, speaker diaphragms were mainly made of composite materials mainly made of pulp, but with recent advances in polymer chemistry, materials suitable for speaker diaphragms have emerged.
Speaker diaphragms are sometimes made by injection molding.

A mold for injection molding a diaphragm such as No. 11;- is shown in FIG. 5, and an injection molded diaphragm is shown in FIG.

In the mold shown in FIG. 5, a cavity 2 having the same shape as the diaphragm 3 is formed by a male mold 1a and a female mold 1b.

Then, molten resin is injected from an injection nozzle 2a communicating with this cavity 2 and fills the cavity 2. After waiting for the resin to solidify, the male mold 1a and the female mold 1b are opened, and the resin solidified in the shape of the diaphragm 3 is released. Take it out.

After removing the parts corresponding to the injection nozzle 2 from this resin to form the diaphragm 3, edges and the like were attached.

[Problem to be solved by the invention]

Conventional injection-molded diaphragms 3 are made of a single material and cannot fully satisfy the characteristics required for a speaker, so they are used as a composite material by bonding them with other materials. may be done.

In such a case, it is necessary to attach several sheets together.

In addition, in such an injection molded diaphragm, an edge formed of a different material is attached to the periphery of the diaphragm 30 so that the diaphragm can vibrate freely, so the formation and attachment of the edge is difficult. This requires a lot of effort.

[Purpose of the invention]

The present invention eliminates the above-mentioned problems of the conventional injection molded diaphragm, forms a vacuum-formed diaphragm and an injection-molded diaphragm integrally and simultaneously, and improves the characteristics of the diaphragm as a composite material. To provide a diaphragm for a speaker and a method for manufacturing the same, which can not only improve the diaphragm but also eliminate the need for the labor of bonding to make a composite material, and also eliminate the labor of splitting and pasting edges. [Summary of the Invention] In order to achieve the above-mentioned object, the present invention forms a suction hole on one side of a diaphragm-shaped cavity of a mold, and applies a thermoplastic sheet to the suction hole to apply a vacuum. After the molding, the resin is injection molded into the cavity and integrally molded with the sheet.

[Embodiments of the invention]

Next, an example of implementation of the present invention will be described with reference to FIGS. 1 to 4.

As shown in FIG. 1, the mold used in this example includes a cavity 5 having the same shape as the diaphragm 4 in FIG.
At the peripheral edge of the cavity 5 where the male mold 6a and the female mold 6b touch, a concentric wave pattern 8, which is to become the edge 7, is formed.

In the male mold 6a, a small-diameter suction hole 9 is bored in the entire surface of the part forming the cavity 5, and a gate 10 serving as an injection hole is provided in the center of the part forming the cavity 5 of the female mold 6b. is formed.

With such a mold separated, as shown in Fig. 2, a thermoplastic sheet 11, for example, a sheet of vinyl chloride, polyester, polyurethane, etc. with a thickness of 0.1 to 0.2 mm is brought into contact with the mold, and the mold is separated. The periphery is brought into close contact with the male die 6a.

Then, while heating the thermoplastic sheet 11, the suction holes 9 are
The sheet 11 is formed into a diaphragm shape as shown in FIG. 3 by a vacuum forming method in which the air between the male mold 6a and the sheet 11 is sucked out and the entire surface of the sheet 11 is brought into close contact with the male mold 6a.

At this time, the portion in contact with the waveform 8 becomes a concentric waveform that will later become the edge 7.

In this way, when the molding of the sheet 11 is completed, the male die 6a and the female die 6b are brought into contact as shown in FIG.
The resin 12 in a molten state is injected from the mold, and when the cavity 5 is filled with the resin 12, the mold is cooled to solidify the resin 12.

In terms of specific elastic modulus and internal loss, the resins used for this injection molding include simple polypropylene, polypropylene 60-9 Qwt% + mica 10-4 Qwt%,
Polypropylene 60-90wt% 10-carbon fiber 10-4
Q w t% etc. are suitable.

Note that the appropriate thickness is 0.2 to Q, 5 mm.

At this time, if flaky graphite, mica, etc. are mixed into the resin, flow marks that flow radially from the center will appear on the surface of the diaphragm 4, and if short glass fibers, etc. are mixed, flow marks will appear, creating a beautiful appearance. At the same time, the strength can be increased.

Then, by injection molding of this resin 12, the sheet 11
are welded and integrated to form a composite material.

The diaphragm 4 with the resin 12 solidified in this way is then placed in the male mold 6a.
The diaphragm 4 is manufactured through operations such as removing the gate 10 and cutting the outer periphery of the edge 7 of the sheet 11.

〔Effect of the invention〕

As described above, in the present invention, a vacuum-formed thermoplastic sheet and an injection-molded resin are integrated by welding, and can be manufactured using one injection molding machine.

Therefore, not only can a speaker diaphragm made of a composite material made by polymerizing multiple layers of different materials be manufactured without the need for a bonding process, but it is also possible to form edges at the same time.
The manufacturing process is greatly simplified.

Therefore, long-lasting speaker diaphragms made of composite material can be provided in large quantities at low cost.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the molding state of a mold according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the male mold and a slope view of the sheet, and FIG. 3 is a cross-sectional view of the molding state of FIG. 2. Figure 4 is a sectional view of the speaker diaphragm according to the present invention, and Figure 5 is a cross-sectional view of the speaker diaphragm according to the present invention.
The figure is a sectional view of a conventional molding die for a speaker diaphragm, and FIG. 6 is a front view of the speaker diaphragm manufactured as shown in FIG. 4... Vibration plate, 5... Cavity, 6a... Male type, 6b... Female type, 7... Edge, tail... Wave type, 9...
... Suction hole, 10... Gate, 11... Sheet, 1
2...Resin. Patent applicant: Pioneer Corporation Figure 1

Claims (2)

[Claims] (1) A composite material is made of a diaphragm sheet that is integrally formed up to the edges by heating and suctioning a thermoplastic sheet, and a resin that is integrally formed on one side of the sheet by injection molding except for the edges. A speaker diaphragm characterized by: (2) A suction hole is formed on the surface of an injection mold having a cavity in the shape of a speaker diaphragm, which forms one surface of the speaker diaphragm, and a thermoplastic sheet is brought into contact with this mold surface. A vibration plate for a speaker, characterized in that the sheet is formed into the shape of a speaker diaphragm by vacuum forming using heating and vacuum suction, and then resin is injected into a cavity of the mold to form a speaker diaphragm. Method of manufacturing the board.