JPS5916494A - Diaphragm for speaker - Google Patents

Abstract

PURPOSE:To simplify the manufacturing process and to attain remarkable cost reduction, by using a single material of inorganic foamed body for forming an incorporated hollow construction. CONSTITUTION:A diaphragm for speaker 14 is formed with an incorporated hollow construction of an inorganic foamed body 11. Cavities 12 are formed with a prescribed pitch from the outer circumference of the foamed body 11 to the center and ribs 13 and provided radially. Thus, the same property as Al is attained with low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a cone-type or flat-plate type speaker diaphragm.

Conventional structure and its problems Conventionally, the diaphragm with a honeycomb sandwich structure, which is most commonly used as a flat plate speaker, has a centrally symmetrical honeycomb core made of 20 μm thick aluminum, as shown in Figure 1. Aluminum surface material 2 is adhered to both sides of 1. The diaphragm made of this nicum sandwich structure is obtained through a honeycomb core manufacturing process, a surface layer manufacturing process, and a core material-surface material bonding process. In the manufacturing process of the core material, an adhesive is applied to a roll of aluminum foil in two types of patterns, and a prescribed number of foils are laminated alternately and heated to obtain a laminate. Next, the honeycomb core for the diaphragm is made by rotating and rolling it out on the individual honeycomb pieces.Meanwhile, in the manufacturing process of the surface layer, an adhesive is applied to the aluminum. A punched face (4) is obtained by punching it into a predetermined shape.Next, by a heat bonding process, surface material is bonded to both sides of the honeycomb sandwich diaphragm to obtain a honeycomb sandwich diaphragm.In this way, conventional flat plate diaphragms require less man-hours. Due to the large number of scales used in the construction, the cost is high, and its use is limited to HlFl, and it will not be expanded to a popular price range13.
:j was difficult.

OBJECTS OF THE INVENTION An object of the present invention is to obtain a low-cost, high-performance speaker diaphragm by simplifying the structure of the diaphragm and reducing the number of manufacturing steps.

Structure of the Invention The speaker diaphragm of the present invention is made of an integral hollow structure made of inorganic foam. In other words, the 8 levers and the surface material are made of the same material, and the diaphragm has an integrated structure that eliminates the need for adhesives, which cause increased weight. Inorganic foams such as glass foams and carbon foams with low density and high elasticity are used for this purpose. Although there are conventional diaphragms made of plastic foams such as urethane and styrene, these foams have low bending strength. Normally, the apparent density of a flat plate diaphragm using a honeycomb or the like is 0.4 to 1.09/cA, and an example of an inorganic foam is glass foam (density 2.0/cA).
09/cil), further increase the apparent density to
~ It is necessary to lower it to a certain extent. Therefore, by machining or the like, a cavity is provided in a shape that does not reduce the rigidity of the diaphragm as much as possible. In other words, the density is reduced while leaving the ribs in the diametrical direction, which have a large effect on the resonance frequency of the diaphragm.

DESCRIPTION OF EMBODIMENTS FIGS. 2 and 3 show an embodiment of the present invention.
In the figure, 14 is a circular flat plate diaphragm, and glass foam 11 developed as a heat insulating material (commercial name 111: Cellome, Toyota Boshoku (manufactured by 90, density -〇, 2 gA'A elastic modulus -1)
, 25 x io 10 dyn/(.J) is cut into a disk shape, cavities 12 are formed at regular intervals from the outer peripheral surface toward the center, and ribs 13 are provided in the radial direction.

In this way, ribs 1 are formed in the radial direction on the disk-shaped glass foam 11.
3, it is possible to minimize the decrease in rigidity of the diaphragm and to make it lighter. Also, this sky 11. The shape of il is not limited to a rectangular shape, but a circular shape can produce the same effect (j), so a circular shape is preferable in consideration of the force resistance.

The physical properties of various foam materials are shown in the table below.

Margins below Physical properties by various foaming months By the way, when forming a glass foam with a square cross-section and a cross-sectional shape, when changing the wall thickness while keeping the cross-sectional area constant, the smaller the wall thickness, the larger the thickness. Become. Figure 4 shows the change in bending rigidity. In Figure 4,
The position indicated by point A is the bending stiffness of alumino-nicam with the same weight as the glass foam, but the wall thickness to obtain the same characteristics as alumino-nicam using glass foam is 0.72.
This indicates that the value is mm. These results show that it is possible to obtain properties equivalent to those of aluminum anicum at low cost by machining the glass foam into an integral structure of a single material.

Effects of the Invention As described above in detail, according to the present invention, the manufacturing process can be simplified by forming an integral hollow structure using a single material of inorganic foam, and the cost can be significantly reduced. Moreover, since it has a one-piece hollow structure, it is easy to use without using any adhesive.
(It is also effective in chemical conversion, and there is no deterioration in physical properties due to the adhesive layer.

This has the advantage that necessary and sufficient diaphragm characteristics can be obtained by using a lightweight and highly rigid inorganic foam.

[Brief explanation of the drawing]

Fig. 1 is a two-sided view of a conventional diaphragm in which a part of the surface material is cut out to form a core shape, Fig. 2 is a top view showing an embodiment of the speaker diaphragm of the present invention, and Fig. 3 is a side view of the same diaphragm, and FIG. 4 is a diagram showing the relationship between the thickness and bending rigidity of the same diaphragm. 14... Vibration plate, 11... Glass foam, 1200119. Hollow, 13...ribs. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 No. 4' 4th factor ＾T ((/i) (I/θ−勺

Claims (1)

[Scope of Claims] (1) A diaphragm for a speaker characterized by being made of an integral hollow structure made of inorganic foam; (2) the inorganic foam is a glass foam having a density of 0.39/aA or less. A diaphragm for a speaker according to claim 1, characterized in that: (3) The speaker diaphragm according to claim 1 or 2, characterized in that ribs are formed radially from the center toward the outer periphery.