JPS5883497A - Diaphragm - Google Patents

Abstract

PURPOSE:To incorporate a diaphragm and a drive coil bobbin without a joint, by taking a flat bottom part of deep-drawn formed part with the flat bottom made of aluminum alloy foil as an outer shell of a disc type diaphragm and a cylindrical leg extended from the flat bottom as the drive coil bobbin. CONSTITUTION:An aluminum alloy foil being a formed member is located on a female die, the circumference of holes of the female die is fixed, the foil is heated at a prescribed temperature and the formed member is pressed on the female die for the formation. The deep-drawn forming with flat bottom thus obtained becomes an outer shell 6. Succeedingly, the length of the ''leg'' of the outer shell is cut into a prescribed size, fine conductors are wound on the ''leg'' of the outer shell to form a driving coil. The bottom of the outer shell of a diaphragm with the drive coil is flat and when the bottom is formed to a prescribed circular arc, this becomes a dome type diaphragm with the drive coil.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a diaphragm used in a speaker, and in particular to a diaphragm with a sandwich-inch structure that achieves a structure effective in maintaining rigidity and easy bonding of a core material and a surface material. It is.

Figure 1(a) shows the joint between the diaphragm and voice coil, which is often used when using a sandwich structure as a diaphragm.
It is shown in FIG. 10(b), which is a detailed view of the joint A. In the figure, 1 is the core material of the sand inch structure, 2-1 and 2-2 are the surface materials of the sand inch band body, and 4 is the bobbin of the voice coil. The bobbin 4 is bonded with an adhesive 5 to the surface material 2-2, which is the surface opposite to the sound radiation surface of the sand-inch structure diaphragm. According to this struct.

Surface material 2-2 and bobbin 4 on the back side of the sand inch structure
the connection part between the core material 1 and the core material 1 and the surface material 2-1.2
-2, there is inevitably a latent cause of a decrease in rigidity, which causes a decrease in resonance frequency and vibration energy loss. Although the structure is simple, in manufacturing this structure, the connection between the surface material 2-2 on the back side and the tip of the bobbin 4 must be abutment of the end face of the bobbin, and the core The connection between material 1 and surface material 2-1.2-2 is as follows.

When a honeycomb is used as the core material, the end face of the core material is an ultra-fine wire, and when a foam material or a three-dimensional network structure is used as the core material, the end face of the core material is a sparse tip, and In either case, the core material and the surface material abut against each other, resulting in a connection that requires the use of a large amount of adhesive, resulting in an increase in weight, which is disadvantageous.

The purpose of the present invention is to eliminate the drawbacks of the prior art based on the joining of the diaphragm and the voice coil bobbin and the bonding work thereof, which caused the above-mentioned reduction in rigidity and the complexity of the assembly process. To provide a structure in which a diaphragm and a bobbin are integrated, which is effective in maintaining rigidity and can be easily manufactured. The present invention is.

In order to achieve the above object, the flat bottom of the aluminum alloy foil flat-bottomed molded product is used as the outer shell of the disc-shaped diaphragm, and the cylindrical legs extending from the flat bottom are used as the drive coil bobbin. It is seamlessly integrated with the drive coil bobbin.

In addition, since the flat bottom part is extremely thin, in order to maintain the rigidity of that part, plastic foam is pasted on the flat bottom and its surroundings, and this is then covered with a lid (back plate) made of aluminum alloy foil. Alternatively, an aluminum alloy foil lid (back plate) with a small hole in the center is arranged at a predetermined distance from the flat bottom surface, and a foamed resin material (for example, acrylic, polyurethane, or vinyl chloride resin liquid) is inserted through the small hole. is injected and heated to foam and solidify to fill the space between the flat bottom and the back body, and at the same time, the flat bottom, its four circumferential parts, and the back plate are bonded together. Furthermore, if a drive coil is wound around a cylindrical part (hereinafter referred to as "leg") extending from the flat bottom part, the leg part is used as a drive coil bobbin.

The bobbin and diaphragm are seamlessly integrated.

Improves rigidity. The present invention is characterized in that the diaphragm and the drive coil bobbin are integrated as described above.

An embodiment of a diaphragm according to the present invention will be described below with reference to one drawing. FIG. 2(a) shows the structure of a diaphragm in which a sandwich structure disc-shaped diaphragm and a drive coil bobbin are integrated without a joint according to the present invention, and FIG. 2(b) shows part B of FIG. 2(a). FIG. First, aluminum alloy foil, which is the material to be formed, is placed on a female mold that has been drilled into a predetermined shape and size, and the area around the female mold hole is fixed so that the temperature is lower than the so-called recrystallization temperature of aluminum (approximately 230°C). The lower limit is 10°C higher than the temperature of about 300°C where crystal grains grow.
Heating at a temperature within a range with the upper limit being a lower temperature, and spraying with compressed air or compressed nitrogen of 3 to 191 kept at the same temperature as the heating temperature.

The material to be molded is pressed into the female mold and molded. The outer dimensions of the molded body obtained here correspond to the dimensions of the female mold. Moreover, the flat-bottomed molded body obtained here becomes the outer shell body B shown in FIG. Note that during the above molding, water or oil at the same pressure as the compressed gas may be used instead of the compressed gas. However, if oil is used, cleaning is required to degrease the molded body.

Next, the length of the legs of the outer shell obtained as described above is trimmed to a predetermined length to complete the outer shell.Next,
A drive coil is constructed by winding thin conductive wires around the "legs" of the outer shell using a conventional and widely used method. The bottom surface of the outer shell of the diaphragm with a drive coil obtained here is flat, but if this bottom is formed into a predetermined arc, it is obvious that this will be a dome-shaped diaphragm with a drive coil. Not worth it. In addition, considering the difficulty of molding, arc molding of the bottom part is easier to mold since it is necessary to maintain the squareness of the corners of the flat molding of the bottom part.

The arcuate bottom molded product can be an intermediate molded product for the flat bottom molded product.

Next, as shown in Fig. 2, a core material 7 is created by inserting and gluing a plastic foam plate of a predetermined thickness in contact with the inner bottom of the outer shell with the drive coil, and then inserting and bonding the core material 7 with aluminum alloy foil. The bottom part is reinforced with a sand inch structure. Also, here inside the outer shell,
A back plate 8 with a small hole in the center is placed at a predetermined distance from the bottom surface (this size corresponds to the thickness of the plastic foam plate), and from the small hole, the material liquid of acrylic resin foam, the urethane resin Inject foam material liquid or vinyl chloride resin foam material liquid.

When this is heated at a foaming temperature determined by the foam material liquid used to promote foaming of the resin, and further cooled and solidified, the space between the bottom of the outer shell and the back plate is filled with the foam. Additionally, the bottom of the outer shell, its periphery, and the back plate can be bonded to each other via the foam to form a sandwich structure at the bottom.

As described above, a disk-shaped diaphragm in which the drive coil bobbin and the diaphragm are seamlessly integrated can be obtained. Using aluminum foil as the material to be formed,
This is heated to a temperature of 245°, and at the same temperature the pressure is 4.
1. Spray compressed air and press the molded material into the designated female mold for about 10 seconds.

A cylindrical outer shell with a flat bottom having a diameter of 22M and a "leg" length of 11M was obtained. Next, measure the specified size from the bottom (9.5 in this case).
1EII) At a distant position, turn the ends of the legs of the outer shell to adjust the dimensions, and then use the conventional method (extrapolating a flat-bottomed cylinder to the winding core) to make one cylinder. Wrap the conductor wire a predetermined distance (4.21111 in this case) starting from a position 0.5 degrees away from the end surface of the part,
A drive coil was provided. Thereafter, as shown in FIG. 2, a foam with a foaming ratio of 20 times (bulk density p, 0.5 g) and a diameter of 21.
8. Apply epoxy resin adhesive to the entire surface of a 1-thick acrylic resin foam and press it until it touches the inner bottom surface of the outer shell, and then press it into the outer shell until it touches the inner bottom surface of the shell, and then press the acrylic resin foam with a circumferential lip of 21mm in diameter.
A back plate made of corrosion-resistant aluminum with a thickness of 8 mm and a thickness of 15 μm was pushed in to cover the acrylic resin foam, and this was
A disc-shaped diaphragm with a drive coil that is heated at a temperature of 0 to 80°C for 1 to 2 hours to harden the adhesive, and the flat bottom part becomes a sandwich structure.The drive coil bobbin and diaphragm are seamlessly integrated. I got it. Comparing the characteristics of the diaphragm obtained here and the diaphragm/drive coil with the conventional structure shown in FIG. 1, the weight of one diaphragm is 175 mg/240 mg.

The product of the present invention had a reduction of 6 smg (37%).

Furthermore, the high resonance frequency due to the peripheral drive of the vibrometer is 8.4 kHz/6.2 kHz, which is 2 kHz higher in the product of the present invention, contributing to improved rigidity.

[Example 2] Using the same method as described in Example 1, an outer shell with a flat bottom of the same shape and size and around which a driving coil was wound was made, and the central part of the back plate used in Example 1 was attached to this. 1.5. A small hole with a diameter of m is drilled from the inner bottom surface of the outer shell.
Placed apart. Thereafter, a molten (warm 120°C) -K vinyl chloride resin solution containing the blowing agent azodicarbonamide is poured into the space formed by the bottom surface of the outer shell and the back plate through the small hole drilled in the back plate. (570-) to 20
1CI115 was injected and heated at a temperature of 140 to 150[deg.] C. to foam the ivyvinyl chloride to fill the space, and then cooled to room temperature and solidified. As a result, the outer shell and the back plate were bonded with vinyl chloride resin, and a disk-shaped diaphragm with a drive coil was obtained in which the drive coil bobbin and the diaphragm were seamlessly integrated with each other with a flat bottom having a sand inch structure. The mass of the diaphragm obtained here is 160 mg,
The high resonance frequency due to vibrometer peripheral drive is 8.8
It was kHz.

[Example]

Using corrosion-resistant aluminum foil with a thickness of 30 μm as the material to be formed,
By the same method as described in Example 1 above.

The material to be formed was heated at 275°C, and pressed into a female mold with a diameter of 29M using compressed water at a pressure of io'l for about 16 seconds at a temperature of 20OA-210°C. A cylindrical outer shell with a flat bottom having a length of 15 fi was obtained. Next, at a position 11.2 ya away from the bottom, the ends of the "legs" of the outer shell were cut to adjust the dimensions, and further, by the same method as described in Example 1, 0.51 ya from the end of one cylindrical part was cut. A driving coil was installed by winding a conductive wire over a distance of 50 times starting from a distant position.Next, a driving coil was placed inside the flat-bottomed diaphragm outer shell with the driving coil obtained above, as shown in Fig. 2. As shown, an acrylic resin foam with a foaming ratio of 20 times, a diameter of 28.7M, and a thickness of 1.8 shoes was coated with epoxy resin adhesive on the entire surface, and an outer shell was prepared in the same manner as described in Example 1. 9 Then, as in Example 1, the diameter was 28.8wI,
A back plate with a peripheral rib of 20 μm thick corrosion-resistant aluminum foil was pressed to cover the acrylic resin foam, and then it was heated in the same manner as in Example 1 at a temperature of 70-80° C. for 1.5
By heating for a period of time to harden the adhesive, a dusk-shaped diaphragm with a drive coil was produced, in which the drive coil bobbin and the diaphragm, whose flat bottoms constituted a sand inch structure, were seamlessly integrated. The mass of the diaphragm obtained here was 260 mg,
It is 20 mg lighter than the conventional structure shown in Figure 1.
Furthermore, a value approximately 1 kHz higher than that of the conventional structure shown in the vibrometer peripheral drive was obtained.

Here, the mass and high-frequency resonance frequency of the sand-inch structure disk in Example 3, which adopted the method shown in Example 2, were almost the same as those of Example 3.

As explained above, in the conventional sand-inch structure disk-shaped diaphragm, the sound wave emitting surface and the driving force holding surface form a pair of front and back surfaces with a light core material in between, and the drive coil bobbin and the back surface of the diaphragm However, according to the present invention, there is a problem in maintaining rigidity, a large loss in driving force transmission, and an unavoidable increase in mass and work due to the use of adhesive. By making the diaphragm outer shell and the bobbin using a long-legged cylinder with a flat bottom, and integrating the two into an integral structure without using adhesive or bonding work, all of the drawbacks of the prior art described above can be eliminated. can.

[Brief explanation of the drawing]

FIG. 1(a) is a sectional view showing the structure of a conventional sand-inch structure disk-shaped diaphragm, and FIG. 1(b) is a partial sectional view showing details of the voice coil bobbin joint A in FIG. 1(a).
FIG. 2(a) is a sectional view showing the structure of an embodiment of the diaphragm according to the present invention, and FIG. ... Outer shell 7 ... Core material 8 ... Back plate attorney Junnosukeichi Nakamura 59'! 1'1 Figure (b) Figure 2 (Q) (b) 595-

Claims (1)

[Scope of Claims] (1) A bottom part of a molded product with a bottom made of aluminum alloy foil, a thin plastic foam layer provided in contact with the inner surface of the bottom part, and a thin plastic foam layer (7) in contact with the thin plastic foam layer.
The diaphragm of the sandwich structure is formed by the aluminum alloy foil provided with the aluminum alloy foil. A diaphragm characterized in that a cylindrical leg of aluminum alloy foil connected to the diaphragm is wound with thin wire to form a drive coil bobbin. (2. In the diaphragm according to claim 1,
A thin plate of plastic foam is bonded to the inner bottom of a molded product with a bottom made of aluminum alloy foil, and the surface of the thin plate of plastic foam is further covered with a lid made of aluminum alloy foil that is placed in contact with the thin plate of plastic foam. A diaphragm characterized by forming a structure. (6) In the diaphragm according to claim 1,
A lid made of aluminum alloy foil having a small hole in the center is placed at a predetermined distance from the inner bottom surface of the molded product with a bottom of aluminum alloy foil, and a plastic foam material is injected through the small hole. 1. A diaphragm characterized in that a sandwich structure is formed by heating and filling an intermediate portion between the bottom surface and the lid with plastic foam.