JPS58154998A - Manufacture of diaphragm for speaker - Google Patents

Abstract

PURPOSE:To increase the strength, by combining the 1st metal mold having rugged pattern with the 2nd metal mold having a through-hole wider than the width of the recessed part of the 1st metal mold and being the same pattern as the 1st metal mold, leaving a connecting margin for a part being in parallel with the surface member and eliminating unnecessary parts. CONSTITUTION:As a thermoplastic resin film 11, a polyarylate resin, 100mum in thickness is used, the resin film is heated to about 350 deg.C and placed on a forming metal mold as shown in Fig. (a) after softening, air is suctioned from a suction hole 13 as shown in Fig. (b) to form a core member 19 having the pattern shape where ruggedness extended radially is arranged circumferentially alternately. After picking up the core member 19 together with the 2nd metal mold 16 as shown in Fig. (c), the projection of the core member 19 projected from the 2nd metal mold 16 along a cutting line A is cut with a knife blade to obtain the core member cut into a diameter of 28mm..

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a speaker diaphragm in which a surface material is attached to the surface of a core material having many irregularities formed by forming a thermoplastic resin film in vacuum, pressure, or vacuum pressure. The purpose is to provide a method of manufacturing a speaker diaphragm that can increase the strength without significantly compromising weight reduction.

In general, most speaker diaphragms are made of paper pulp, and the diaphragm has a cone shape.

Therefore, the position of the sound source is different between the inner circumference and the outer circumference of the speaker diaphragm, creating a phase difference, making it difficult to obtain a speaker with flat frequency characteristics. On the other hand, a speaker with a flat diaphragm does not have the front chamber effect seen in cone-shaped speakers, and is advantageous in flattening frequency characteristics. In the case of a flat plate speaker, when a conventional paper diaphragm is used as a diaphragm, split vibration tends to occur due to its low bending rigidity, making it impossible to obtain flat characteristics over a wide band.

A sandwich structure can be considered to increase bending rigidity with a flat plate. Until now, many sandwich structure imaging plates with aluminum honeycomb as the core material have been used, but aluminum honeycomb has a complicated manufacturing process and is therefore expensive.
A popular stereo device.

It is difficult to use as a speaker for radio receivers, television receivers, etc. In addition, in order to obtain a sand-inch structure diaphragm at a low cost, a thermoplastic resin film is made into a core material with many irregularities by vacuum, pressure-air, or vacuum-pressure forming, and a surface material is pasted on both sides of this core material to vibrate. There is a way to make it into a board. In this case, the core material has a portion parallel to the surface material, resulting in a portion that overlaps with the surface material, which is not efficient in terms of weight. Therefore, the convex portions of the formed film are cut to reduce the weight of the diaphragm and increase efficiency.

FIG. 1 shows a conventional method of manufacturing a speaker diaphragm. In FIG. 1, 1 is a thermoplastic resin film, and 2 is a mold. This molding die 2 has a concavo-convex pattern and a first die 3 having a suction hole at the bottom of its concave portion, and a first die 3 having a concavo-convex pattern with the same pattern as the concave-convex pattern of the first die 3 and the same size as the above four parts. It is composed of a stack of second molds 4 having through holes. In this manufacturing method, as shown in FIG. 1a, the thermoplastic resin film 1, which has been heated and softened in advance, is placed facing the above-mentioned molding die 2, and in this state, suction is applied as shown in FIG. 1blc. However, the above 1. The thermoplastic resin film is molded using a molding die 2 consisting of a combination of second molds 3 and 4, and as shown in FIG. 1C, the first mold 3 is removed and then the second mold 4 is The convex portion of the film protruding from the core material 5 is cut along the second mold 4 with a knife blade or the like, and then surface materials 6 and 7 are adhered to both sides of the core material 5 as shown in FIG. 1d. However, according to this method, although the weight of the diaphragm can be reduced, the adhesion area between the cut end face of the core material and the surface material, which is an extremely thin film, is small and the adhesion strength is also weak. For this reason, there was a problem that sufficient reliability as a speaker could not be ensured.

The present invention eliminates these conventional drawbacks,
A first mold having an uneven pattern is combined with a second mold having the same pattern as the first mold and a through hole wider than the width of the recess of the first mold, resulting in two recesses as a whole. Equipped with a molding mold, the thermoplastic resin film is vacuumed by this molding mold.

A core material having a large number of concave and convex portions is molded by air pressure or vacuum pressure forming, and after the second mold of the mold is taken out together with the molded core material, the convex portion of the core material that protrudes from the second mold is cut. A core material is formed by removing the core material and leaving a portion parallel to the surface material, and then surface materials are bonded to both sides of the core material. According to this manufacturing method, by cutting the part of the core material molded in two stages that protrudes from the second mold along the second mold, a part of the part parallel to the surface material is cut. Since unnecessary portions can be removed at the same time as they are left as they are, it has the advantage of increasing strength without compromising weight reduction too much.

Hereinafter, a method for manufacturing a speaker diaphragm according to the present invention will be described with reference to drawings of embodiments.

2 and 3 show an embodiment of the present invention,
In FIGS. 2 and 3, 11 is a thermoplastic resin film, and 12 is a mold. This molding die 12 includes a first die 14 having a predetermined pattern of concavo-convex portions and a suction hole 13 at the bottom of the concave portion, and a first die 14 having the same predetermined pattern as the predetermined pattern of the first die 14 and the above-mentioned pattern. It is composed of a second mold 16 having a through hole 16 wider than the width of the recess of the first mold 14, and has two recesses 17 as a whole. Here, the predetermined pattern consisting of the concave and convex portions of the molding die 12 is a pattern in which concave portions 17 and convex portions 18 expanding in the radial direction are alternately arranged in the circumferential direction as shown in FIG. 17 has a two-tiered structure.

Specifically, the thermoplastic resin film 11 has a thickness of 10
Using a 0 μm polyarylate resin film, heat the polyarylate resin film to about 350°C to soften it, then place it on the molding die as shown in Figure 2 a, and in this state, as shown in Figure 2. As shown, air was sucked through the suction holes 13 to form a putter/shaped core material 19 having irregularities extending in the radial direction alternately in the circumferential direction. Fishing, Figure 2 0
After taking out the second mold 16 along with the molded core material 19 in the same direction, the convex portion of the core material 19 protruding from the second mold 16 was cut along the cutting line with a knife blade to obtain a diameter of 2811 mm.
The heartwood cut into pieces 1 was taken out. The weight of this heartwood is 65
! It was I1g. In addition, the weight of the core material obtained by the conventional vacuum forming method of vacuum forming with a mold having an uneven pattern in which uneven parts expanding in the radial direction are arranged alternately in the circumferential direction is 74 mg.
Met. As is clear from this comparison, the core material of this example is lighter than the core material produced by the conventional molding method. Next, a 20-μm-thick layer was used as the surface material 20.21, and a polyester film adhesive (thickness 3
0 μm), and was bonded to the core material under heat and pressure to form a diaphragm. The peel strength between the surface material and core material at this time is 760g.
Met. In addition, the core material 5 formed by the conventional core material cutting method
A diaphragm was prepared in the same manner as above, and the peel strength between the surface material and the core material was measured. As a result, the peel strength was 150f.
According to the present invention, unnecessary parts of the core material can be removed and a margin for adhesion to the surface material can be provided, so that the strength can be increased without significantly impairing the weight reduction of the diaphragm. This makes it possible to provide a speaker with high performance and excellent reliability.

In addition to the examples, the pattern of the heartwood may be triangular, two-circle, diamond, hexagonal, oval, etc., and various ways of arranging it such as concentric, radial, etc. can be considered, and the same effect can be obtained in any case. It is something.

Furthermore, the size of the diaphragm can be applied to larger squawkers and woofers other than those of the embodiments.

[Brief explanation of the drawing]

FIG. 1 is a process diagram for explaining a conventional method for manufacturing a diaphragm for a speaker, FIG. 2 is a process diagram for explaining an embodiment of the method for manufacturing a diaphragm for a speaker according to the present invention, and FIG. The figure is a plan view of a molding die used in the method. 11...Thermoplastic resin film, 12...
...Molding mold, 13...Suction hole, 14...
...First mold, 15...Through hole, 16...
...Second mold, 17...Two-stage recess, 19...
...Heartwood, 20,21...Surface material. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1 1g131 2 (!! //

Claims (1)

[Claims] A first mold having a concavo-convex pattern and suction holes at the bottom of the recess, and a second mold having a through-hole in the same pattern as the first mold but wider than the four-part pattern of the first mold. The thermoplastic resin film is formed by vacuum, air pressure, or vacuum-pressure molding using this mold to form a core material having a large number of unevenness, and then the above-mentioned The second mold is taken out together with the molded film core material, and the convex portion of the film core that protrudes from the second mold is cut and removed, leaving a part of the core material that is parallel to the surface material. A method for manufacturing a speaker diaphragm, characterized by laminating a surface material on both sides of the diaphragm.