JPH045318B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speaker diaphragm and a method for manufacturing the same, and its first object is to realize a core material made of a material with low density and high specific modulus, such as boron. Particularly, it is an object of the present invention to provide a lightweight and high-performance speaker diaphragm. Second
The object of the present invention is to provide a method for manufacturing a speaker diaphragm in which boron, which is a material with a low density and a high specific modulus, can be used as the core material without affecting its machinability.

In general, a speaker diaphragm follows the driving force given by the electromagnetic conversion system within its frequency band with sufficient linearity, and its entire surface vibrates in the same phase (piston vibration). That is considered ideal. Furthermore, from the perspective of sound wave radiation characteristics, a so-called flat diaphragm with a flat radiation surface is considered ideal. With this planar diaphragm, in order to prevent split resonance and widen the piston vibration area, the diaphragm is thicker to provide stiffness due to the shape effect of the cone or dome shape.As a result, the weight of the diaphragm increases and the efficiency of the speaker increases. It had the disadvantage of decreasing. As a way to improve this shortcoming,
A diaphragm with a sandwich structure in which a skin material is bonded to the surface of a core material made of a hollow core has been put into practical use, but even with the use of such a sandwich structure, a sufficient lightweight effect could not be obtained. Therefore,
In order to further increase the effectiveness, attempts have been made to reduce the weight by making the materials that make up the sanderch structure thinner, but thinning the materials reduces the mechanical strength, leading to buckling during assembly, deformation, and damage during operation. There was a problem that partial resonance (plane noise phenomenon) occurred and the sound image characteristics deteriorated.

In order to improve the weight disadvantage of such a planar diaphragm, a material with low density and high elastic modulus is desired, and boron is known as a material that satisfies this requirement. However, boron has poor machining properties such as rolling and molding, making it difficult to process into complex shapes. On the other hand, even if processing techniques such as vapor phase growth and hot pressing in an inert atmosphere are used,
Its range of use is limited, and aluminum and titanium have been the main structural materials for general acoustic transducers. In addition, in a vibrating body with a sanderch structure as described above, the balance between the physical properties of the skin material and the core material is also important. For example, when combining an aluminum core material with a boron skin material, it is difficult to Compared to when the material was used, the contribution of the material's physical properties to the properties was lower, making it difficult to fully utilize the physical properties of the skin material. Furthermore, honeycomb materials and ribbon braided materials have been put into practical use as core materials for the hollow cores of speaker diaphragms with a sanderch structure, but in the case of honeycomb materials, the cells are partially doubled. On the other hand, in the case of ribbon braided materials, long ribbons are bent to a small diameter, so the material must be easy to work with, and the braiding process becomes complicated, resulting in poor productivity. It had

The present invention solves these conventional drawbacks by arranging a plurality of hairpin-shaped core units made of a boron-producing single film in a radial manner to form a hollow core, and forming a hollow core on the surface of the core unit made of boron. It is designed to join skin materials. The core material is made by cutting a laminated material block to the desired thickness by forming a boron film on the surface of the plate, which has been formed into a hairpin shape by ion plating, and then separating the substrate. A core unit made of a single film of boron is then formed, and then a plurality of the core units are arranged radially. According to this structure, since the core material is made up of a plurality of simple hairpin-shaped core units arranged radially, the core unit itself can be composed of a single boron film by applying the ion plating method. Low density, high specific modulus boron can be applied to the core material without being affected by poor machinability. Therefore, it is possible to realize a core material made of boron with low density and high specific modulus, and it is possible to provide a lightweight and high-performance speaker diaphragm.

Here, the shape of the core material, which is the gist of the present invention, is basically one that has an isotropic distribution density with ribs arranged radially from the center of the diaphragm, and since boron, which has poor machinability, is used, It is an assembly of core units formed by the plating method, and is also shaped into a three-dimensional hairpin shape such as a U-shape or trapezoid to increase productivity during assembly and bonding.
Improved strength against torsional stress.

Hereinafter, the speaker diaphragm of the present invention will be explained with reference to drawings of embodiments.

FIGS. 1 and 2 show an embodiment of the present invention, and in the figures, reference numeral 21 denotes a core material having a substantially U-shape and consisting of a plurality of core units 22 made of a boron-producing single film arranged radially; Reference numeral 23 denotes a skin material made of a single boron film bonded to both sides of the core material 21 by thermocompression bonding with an adhesive.

Specifically, the skin material 23 was created by placing the titanium substrate 11 covered with the mask material 12 in a DC ion plating apparatus 13 and performing electron beam evaporation as shown in FIG. As shown in FIG. 4, the DC ion plating apparatus 13 has a substrate 2 and a crucible 4 placed facing each other in a bell jar 1 having an exhaust system, and a thermionic accelerating electrode 3 and an electron beam gun 5 placed near the crucible 4. It is provided with a thermionic accelerating power source 6 for the thermionic accelerating electrode 3 and an ion accelerating power source 7 as a power source for the substrate 2. Then, boron 8 was placed in the crucible 4 as an evaporation source. At this time, boron is evaporated in an atmosphere of 1 to 3 × 10 ^-5 Torr, and 70V is applied to the thermionic accelerating electrode 3 to accelerate the thermionic electrons generated from the crucible 4 and cause them to collide with the evaporated particles of boron. Ionized boron. In addition, during boron generation, a voltage of 0.5 KV was applied to substrate 2 for 2 minutes from the beginning of boron generation, and thereafter
Lower the voltage to 0.1KV and plate for 20 minutes, then remove substrate 2.
A boron layer 14 with a thickness of 15 μm was formed thereon. For the substrate 2, titanium foil with a thickness of 30 to 50 μm is used,
The surface was covered with a mask material 12 having holes of 28 mm in diameter to form a boron layer 14 of a desired size. After the boron layer 14 is formed, the titanium substrate 11 is
A skin material consisting of a single film of boron produced was created by chemically dissolving and removing it with a hydrofluoric acid solution at a concentration of 0.5 to 1.0%. On the other hand, the core unit 2 constituting the core material 21
2, a core jig 16 with a trapezoidal cross section is inserted into a titanium substrate 15 with a thickness of 30 μm which has been previously formed into a substantially U-shaped cross section, and a mask material is inserted into the end of the titanium substrate 15, as shown in FIG. 18 was placed in the DC ion plating apparatus 13, and while rotating around the rotating shaft 17 provided in the core jig 16, it was generated by electron beam evaporation. Then, the titanium substrate 1
A laminated material block 20 on which a boron layer 19 with a thickness of 20 μm has been formed is cut into a width of 9 by using a laser cutter.
Cut into mm. After that, the titanium substrate 15 is chemically dissolved and removed in a hydrofluoric acid solution with a concentration of 0.5 to 1.0%,
A boron core unit 22 having a length of 13.5 mm, a width of 1.5 mm, a height of 0.9 mm, and a thickness of 20 μm was obtained. Then, the plurality of core units 22 described above are arranged radially to form the core material 21.
was configured. At this time, the boron layer for the core unit 22 is generated by the electron beam evaporation method using a DC ion plating device in the same way as for the skin material, while rotating the substrate in an atmosphere of 1 to 3 x 10 ^-5 Torr. Boron was evaporated, and 70V was applied to the thermionic accelerating electrode 3, and thermionic electrons generated from the crucible 4 were accelerated and collided with the evaporated boron particles to ionize the boron. Also, during boron generation, a voltage of 0.5 KV was applied to the substrate 2 for 2 minutes from the beginning of the generation, and thereafter the voltage was lowered to 0.1 KV and plated for 20 minutes to generate a boron layer with a thickness of 20 μm on the substrate 2. Ta. After that, a flat boron skin material 2 with a thickness of 15 μm coated with adhesive is placed on both sides of the core material 21.
3 was thermocompression bonded under conditions of a temperature of 200 to 230°C and a pressure of 1 to 2 kg/cm ² to obtain a flat diaphragm having a diameter of 28 mm and a thickness of 1 mm. The total weight of this diaphragm was 88.6 mg, and the primary resonance frequency was 26.4 KHz.

Comparative Example 1 A core material consisting of a hollow core made by braiding aluminum ribbons with a thickness of 20 μm into a chrysanthemum shape, with a thickness of 15 μm on both sides.
pure boron skin material at a temperature of 200~300℃ and a pressure of 1~
Heat-pressed under the conditions of 2Kg/cm ² , diameter 28mm, thickness approx.
A flat plate diaphragm of mm was fabricated. The total weight of this moving plate was 119 mg, and the primary resonance frequency was 13.2 KHz.

Comparative Example 2 The core material is made of a hollow core made of a chrysanthemum-shaped aluminum ribbon woven with a thickness of 20 μm and a height of 1.9 mm.Thickness on both sides of the core material is 20 μm.
A flat plate diaphragm having a diameter of 28 mm and a thickness of about ¹ mm was produced by thermocompression bonding of aluminum skin materials of 28 mm in diameter and approximately 1 mm in thickness at a temperature of 200 to 230° C. and a pressure of 1 to 2 kg/cm 2 . The total weight of this diaphragm was 142 mg, and the primary resonance frequency was 123 KHz.

In the above description, a boron-generated single film was used as the skin material, but it goes without saying that a laminated material in which the titanium substrate is left without being separated can be used as the skin material.

As detailed above, according to the present invention, it is possible to significantly improve the resonant frequency by fully utilizing the physical properties of the skin material, and also to reduce the weight by taking advantage of the structure and characteristics of the materials used. is possible,
It is possible to provide a high performance speaker with characteristics of wide reproduction band and high efficiency. In addition, the heartwood is
A film produced on the surface of a molded substrate by the ion plating method is separated from the substrate to form a core unit, and since the core unit is assembled, boron with a low density and high specific elastic modulus is mechanically (bent). This has the advantage that it can be applied without processing.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway plan view showing one embodiment of the speaker diaphragm of the present invention, FIG. 2 is a sectional view of the same diaphragm, FIG. 3 is an explanatory diagram of the manufacturing process of the same diaphragm,
The figure is a schematic diagram of the DC ion plating apparatus used to create the skin material and core material of the same diaphragm. 1... Bergier, 2... Substrate, 3... Thermionic accelerating electrode, 4... Boron crucible, 5... Electron gun,
6...Thermionic acceleration power source, 7...Ion acceleration power source,
11, 15... Titanium substrate, 12, 18... Mask material, 14, 19... Boron film, 20... Laminated material block, 21... Core material, 22... Core unit, 23... Skin material.

Claims (1)

[Scope of Claims] 1. A speaker comprising a hairpin-shaped core unit formed by radially arranging a plurality of core units made of a boron-producing single film, and a skin material made of boron bonded to the surface of the core material. diaphragm for use. 2. The speaker diaphragm according to claim 1, wherein the skin material is a laminated material in which a boron film is formed on a titanium substrate or a boron formed single film. 3. A laminated material block with a boron film formed by ion plating on the surface of a substrate whose cross-sectional shape has been formed in advance into a hairpin shape is cut to a desired thickness, and then the substrate is separated to generate boron. A core unit made of a single film is formed, then a plurality of the core units are arranged radially to form a core material, and then a skin material made of boron is bonded to the surface of the core material by thermocompression bonding with an adhesive. A method for manufacturing a speaker diaphragm characterized by: