JPH0345789Y2 - - Google Patents

Description

[Detailed description of the invention] ``Purpose of the invention'' (Industrial application field) The present invention relates to a mold for forming a dome-shaped diaphragm, and in particular, the invention relates to a mold for forming a dome-shaped diaphragm. This invention relates to a mold for molding a dome-shaped vibration system formed by integrally molding a dome part, a coil bobbin part, and an edge part extending horizontally at the lower end of the dome part.

(Prior Art) As shown in FIG. 4, a conventional dome-shaped speaker is constructed by integrally molding a dome diaphragm section 22 and a coil bobbin section 23, and then winding a voice coil 25 around the dome diaphragm section 22. There are two methods in which the vibration system 21 is constructed by attaching a separately molded edge portion 24a to the outer periphery, and another method in which the edge portion 24 is integrally molded on the outer periphery of the dome diaphragm portion 22 and separately molded as shown in FIG. There is a method in which the voice coil 25 is wound around the coil bobbin member 23 and then attached 23a to the diaphragm section 22.

On the other hand, in terms of materials, there are those molded from cloth impregnated with phenolic resin, and those molded from metal foil.
It has also been proposed to integrally mold the dome reaction plate portion 22 and the edge portion 24 from a polyimide resin film (for example, Japanese Patent Publication No. 56-49040).

(Problems to be solved by the invention) However, in the case of the conventional dome-shaped speaker shown in Fig. 3 or 4, since it involves a gluing process, it is not only impossible to obtain assembly accuracy, but also the driving force is low. It has the drawback that the transmission loss is large, and in addition, it takes time for the adhesive to harden, and lead wire processing is troublesome, such as leading out the lead wire of the voice coil 25 from the back side or the front side of the edge portion 24. There were some drawbacks.

In order to eliminate the conventional drawbacks mentioned above, we
We have previously proposed a series of dome-shaped speakers in which a dome part, a coil bobbin part, and an edge part extending horizontally at the lower end of the dome part are integrally molded, and the edge part is supported within a magnetic circuit.

As mentioned above, the vibration system of this type of dome-shaped speaker is one in which the dome part, the coil bobbin part, and the edge part extending horizontally at the lower end are integrally molded. When hot press molding is performed using a mold, it is deep drawing, and with normal molds, material breaks occur at the vertical and corner parts where the coil bobbin part is to be molded, so it is difficult to mold the specified vibration system. Can not.

That is, what is proposed in the above-mentioned Japanese Patent Publication No. 56-49040 has a dome portion 22 and an edge portion 24.
The dome-shaped speaker according to our proposal described above can be heat-formed because it is integrally molded with a polyimide resin film and a coil bobbin, which is a separate member, is joined. Since the vibration system requires deep drawing, normal molds cannot be used.

The purpose of this invention is to mold a heat-resistant resin film vibration system by heat-press molding a heat-resistant resin film sheet and integrally molding a dome part, a coil bobbin part, and an edge part extending horizontally at the lower end of the dome part. Our goal is to provide a mold that can do this.

``Structure of the invention'' (Means for solving the problems) The dome-shaped diaphragm according to the invention is made by hot press-molding a heat-resistant resin film sheet with male and female molds, thereby forming a dome part, a coil bobbin part, and its lower end. This is a mold for molding a dome-shaped vibration system in which an edge part extending horizontally is integrally molded, and the molding clearance formed between the male and female molds is the molding clearance of the coil bobbin part. It is formed to be larger than the molding clearance.

(Function) The male and female molds for hot-pressing the heat-resistant resin film sheet have a coil bobbin molding clearance larger than the dome molding clearance, and even during deep drawing, the coil bobbin part is formed at the vertical and corner parts. The dome part, the coil bobbin part, and the edge part extending to the lower end of the dome part are integrally molded.
It is possible to mold a diaphragm made of heat-resistant resin film that has a roughly straw hat shape.

(Example) An example of the dome-shaped diaphragm molding die according to the present invention will be explained based on FIGS. 1 to 3.
The figure is a cross-sectional view of the entire vibration system, Figure 2 is a cross-sectional view of the diaphragm when a hard ceramic thin film is formed on the surface of the heat-resistant resin film sheet used, and Figure 3 is a cross-sectional view of the main parts of the molding die. FIG.

In the figure, 1 indicates the entire dome-shaped diaphragm,
A dome portion 2, a coil bobbin portion 3, and an edge portion 4 extending horizontally from the lower end thereof are integrally molded from a heat-resistant resin film, and a voice coil 5 is formed in the coil bobbin portion 3.

The mold 6 for heat press-molding the heat-resistant resin film sheet is composed of a male mold 7 and a female mold 8, and is formed between the male mold 7 and the female mold 8. The coil bobbin forming clearance 13 is larger than the dome forming clearance 12, and the edge forming clearance 14 is the same as the dome forming clearance 12. In addition, the corner portion 15 from the outer periphery of the dome portion forming clearance 12 to the coil bobbin portion forming clearance 13 is formed to have a gently sloped curved surface, which allows the film material to be stretched during press forming. Prevents it from tearing. Note that the curvature of the corner portion 15 described above should be set depending on the film sheet material.

Next, a specific example in which a diaphragm was molded using the above molding die will be described.

Example 1 After preheating a 75 μm polyimide film (manufactured by Ube Industries, Ltd., trade name: Kopilex-R) at a temperature near the glass transition point, a mold 6 as shown in FIG.
A straw hat-shaped diaphragm having a dome portion 2, a coil bobbin portion 3, and an edge portion 4 extending horizontally at the lower end thereof was obtained by hot press molding at 300 to 350°C. In this case, the inner diameter of coil bobbin 3 is
It was 25.

When a voice coil 5 was formed on the coil bobbin portion 3 of this diaphragm and assembled as a tweeter unit, the characteristics were Q-damped in the low range and smooth, and wide ranges could be reproduced up to 20KHz.

Example 2 PEEK film 75μ (manufactured by Mitsui Toatsu Co., Ltd., product name
A diaphragm was obtained in the same manner as in Example 1 using TALPA film. Since this PEEK generally has poor adhesion, the voice coil was wound after surface treatment such as acid etching. Note that a tweeter unit incorporating this diaphragm was also able to obtain characteristics similar to those of Example 1.

In addition to the heat-resistant resin films used in Examples 1 and 2 described above, aramid films with a high Young's modulus are promising. In addition, these heat-resistant resin film sheets can be coated with hard carbon thin films (including diamond-like thin films) and hard ceramic films such as silica films using low-temperature processing temperatures (around 200℃) such as ion plating and low-temperature plasma PUD methods. It is possible to form a vibration plate using a thin film that has been vapor-deposited to increase its rigidity. FIG. 2 shows a hard thin film ceramic layer 11 formed on the surface of a film sheet substrate 10 in this manner.

"Effect of the invention" According to the dome-shaped diaphragm molding die according to the invention, the male and female molds for hot-pressing the heat-resistant resin film sheet have a coil bobbin part molding clearance larger than a dome part molding clearance. Therefore, there is no material breakage at the vertical and corner parts where the coil bobbin part should be formed during deep drawing, and the dome part, the coil bobbin part, and the edge part extending to the lower end are integrally formed. In addition, it is possible to accurately mold a diaphragm made of a heat-resistant resin film and having a substantially straw hat shape.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the dome-shaped diaphragm molding die according to the present invention, FIG. 1 is a sectional view of the entire vibration system, and FIG. FIG. 3 is a sectional view of a main part of a molding die. Figure 4 is a cross-sectional view showing the vibration system of a conventional dome-shaped speaker, Figure 5
The figure is a sectional view showing another conventional vibration system. 1... Entire dome-shaped diaphragm, 2... Dome part,
3... Coil bobbin section, 4... Edge section, 5...
Voice coil, 6... Mold, 7... Male mold, 8
...Female mold, 9...Clearance, 10...Film sheet substrate, 12...Dome part forming clearance, 13...Coil bobbin part forming clearance, 14...Edge part forming clearance, 15...
...Corner section.

Claims (1)

[Scope of utility model registration request] A mold for molding a dome-shaped vibration system in which a dome part, a coil bobbin part, and an edge part extending horizontally at the lower end are integrally molded by heating and press-molding a heat-resistant resin film sheet with male and female molds. 1. A molding die, wherein a molding clearance formed between the male and female molds is such that a coil bobbin portion molding clearance is larger than a dome portion molding clearance.