JPH0129359B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a flat speaker diaphragm for flat speakers used in audio equipment such as television receivers and tape recorders with radio receivers. .

Structures of conventional examples and their problems In general, most speaker diaphragms are made of paper pulp and molded, and the diaphragm has a cone shape. Speakers using these diaphragms have the disadvantage that it is difficult to obtain a speaker with flat sound pressure frequency characteristics because the position of the sound source is shifted between the inner and outer peripheries of the diaphragm.

In contrast to the above-mentioned speakers, flat-plate speakers, which have a flat diaphragm and align the sound sources, are advantageous in terms of flattening the sound pressure frequency characteristics. Rectangular flat speakers began to be developed as speakers for equipment with limited speaker mounting area, with the aim of making effective use of the limited space and expanding the vibration area.

In the case of these flat diaphragms for speakers, if the diaphragm is simply made into a flat diaphragm, the rigidity against bending is low and split vibration is likely to occur, making it difficult to obtain flat frequency characteristics over a wide band.

Therefore, as a means to solve these problems, a rectangular flat diaphragm is used, as shown in Fig. 1, in which a core material 1 is made of expanded polystyrene or plastic foam, and a surface material 2 such as aluminum foil is adhered to both sides of the core material 1. It is being However, in the case of a diaphragm that uses foam for the entire core material, the cost is relatively low;
Although it has the advantage of good productivity, especially in the case of small flat diaphragms, it is necessary to reduce the thickness of the core material and the foam must be cut with a hot wire, etc. This is the same as when the cut surface of the body contracts due to heat and the foaming ratio decreases.
The weight becomes heavier. Therefore, it had the disadvantage of reduced efficiency. On the other hand, flat plate diaphragms with a conventional aluminum honeycomb structure as the core material, which provides high bending rigidity as shown in Figure 2, have the disadvantage of high manufacturing costs due to the complicated processing process. When adhering the core material and the surface material, when attempting to reduce the weight by reducing the foil thickness of the surface material, the adhesion is performed using heat press, etc., but since there are sealed irregularities within the core shape. However, the shape of the core had the disadvantage that it would come out onto the surface material due to air contraction after the surface material was bonded.

Purpose of the Invention The present invention solves these conventional drawbacks by forming a thermoplastic resin film into a core material with uneven ribs formed by press molding, etc., and providing a flange on the outer periphery to make it easier to cut. It is an object of the present invention to provide a speaker diaphragm that can solve the difficulty in bonding the surface material to the core material, which occurs due to the above-mentioned problems.

Composition of the Invention The flat plate diaphragm for a speaker of the present invention has surface materials bonded to both sides of a flat core material having radially uneven ribs and a flange on the outer periphery by press-molding a thermoplastic resin film, and the adhesive It is equipped with small holes for drying.

According to this configuration, the shape of the core material of the flat diaphragm is made into a shape in which radially uneven ribs are provided by press molding using a thermoplastic resin film (polymer film, etc.), and a flange is further provided on the outer periphery of the core material. By forming the diaphragm into such a shape, it is possible to improve the strength of the diaphragm in the vertical and lateral directions, and to obtain flat sound pressure frequency characteristics up to high frequencies. In addition, by providing a flange around the outer periphery of the core material, when cutting the core material into the required size, the cutting surface is flat, making it easy to cut using a conventional cutting press, etc., increasing productivity. The core shape can be made suitable for. Furthermore, when bonding the core material and the surface material (when a solvent-based adhesive is used), if there are sealed irregularities within the shape of the core material, problems such as difficulty in drying of the solvent occur. Air holes are partially provided on one side (convex part) of the flat plate core material provided with radially uneven ribs, the surface with the flange on the outer periphery and the surface material are first adhered, and after the solvent is dried, air holes are provided. By attaching a surface material to one side (convex portion) provided with holes, the problem that the solvent is difficult to dry can be solved. Furthermore, as a solution to the problem that the solvent is difficult to dry, a small hole is provided on one side (convex part) side of the radial uneven ribs after the diaphragm is made, so that there is no sealed part inside the diaphragm. This problem can also be solved by using a rectangular flat diaphragm.

DESCRIPTION OF EMBODIMENTS The flat diaphragm for speakers of the present invention will be described below with reference to the drawings.

FIG. 3 shows an embodiment of a flat plate diaphragm for a speaker according to the present invention. In FIG. It is made by molding a thermoplastic resin film using radially uneven ribs 4' and 4'', and is provided with a flange 4 on the outer periphery.

After forming the flat core material 4, as shown in FIG. 4, radially uneven ribs 4',
A rectangular flat speaker diaphragm 6 can be produced by attaching surface materials 55' made of light metal foil, polymer film, or the like having relatively high elasticity to both sides of the core material 4 having a shape of 4''. The rectangular flat speaker diaphragm produced in this way can be produced by the process of gluing the surface materials 5, 5' on both sides of the core material 4 formed from a film, so it is said to be highly productive and inexpensive. In addition to having the advantages, by providing the flange 4 on the outer periphery of the core material, when cutting the core material to the required size,
Since the cut surface is flat, it can be easily cut using a conventional cutting press or the like, which has the advantage of being suitable for productivity. Here, when a solvent-based adhesive is used to bond the core material 4 and the surface materials 5, 5', there is a problem that the solvent is difficult to dry if there are sealed irregularities in the shape of the core material. Occur. Therefore, the radially uneven ribs 4',
On one side (convex part) 4'' of the flat core material 4 provided with 4'',
As shown in FIG. 5, the air holes 7 are provided, and the surface material 5 is first
After gluing and drying the solvent from air hole 7,
A surface material 5' is attached to one side (direction c) provided with air holes. Thereby, the above problem can be solved. Furthermore, as a solution to the problem that the solvent is difficult to dry, after making the diaphragm, a sixth
By providing a small hole 8 as shown in the figure,
A hole passing through the surface material 5' and the core material 4 can be formed, thereby eliminating a sealed part within the diaphragm and making it possible to easily dry the solvent. The hole passing through the surface material 5' and the core material 4 only needs to be provided on the mounting side of the voice coil 9, and does not have any effect on the surface of the diaphragm when the speaker is installed. In addition to this, a method can be considered in which air holes 10 are provided on the side surface of the core material as shown in FIG.

The flat diaphragm for speakers of this embodiment can reduce the weight of the diaphragm, and as shown in FIGS. 8 and 9, the vertical bending strength D
and the bending strength E in the lateral direction can be made to be the same, and the strength can be made to be the same as that of the conventional honeycomb shape. As a result, as shown in FIG. 10, it is possible to obtain speaker characteristics that are efficient and have improved high frequency reproduction characteristics. In FIG. 10, F indicates the speaker characteristics of this embodiment, and G indicates the characteristics when a conventional foam is used as the core material.

Note that the characteristics shown in FIG. 10 were evaluated by making a prototype speaker as shown in FIGS. 11 and 12 using the flat diaphragm. Figure 11,
FIG. 12 is a top view and a structural sectional view of the prototype small rectangular flat speaker as seen from the side. In FIG. 11, reference numeral 6 designates the flat plate diaphragm of this embodiment described above, and its outer periphery is supported by a frame 12 via an edge member 11. As shown in FIG. 12, a magnetic circuit consisting of a magnet 13, a yoke 14, and a center pole 15 is attached, and a voice coil 9 supported by a damper 16 is directly bonded to the position of the node that occurs on the flat diaphragm 6. be.

In addition, the reason why the center of the radial uneven rib is shifted to one side from the center of the diaphragm in Fig. 3 is as follows.
Considering the case where a speaker is prototyped using the one-side node drive method, the purpose is to further improve the strength of the diaphragm by arranging the center of the concavo-convex ribs above the voice coil.

Effects of the Invention As detailed above, according to the present invention, a surface material is bonded to both sides of a flat core material made of thermoplastic resin and having radial uneven ribs and a flange on the outer periphery, and for bonding. Since the small hole for drying the adhesive is provided, the glue for adhering the surface material to the flat core material can be dried through the small hole, which has the advantage of further increasing mass productivity.

[Brief explanation of drawings]

1 and 2 are partially cutaway perspective views of a conventional flat diaphragm for a speaker, FIG. 3 is a plan view showing an embodiment of the flat diaphragm for a speaker according to the present invention, and FIG. 4 is a plan view of the same diaphragm. FIG. 5 is an enlarged perspective view of a main part of the diaphragm, and FIGS. 6 and 7 are configuration diagrams showing other embodiments of the flat diaphragm for speakers of the present invention.
Figures 8 and 9 are explanatory diagrams of the bending rigidity of the same diaphragm, Figure 10 is a sound pressure frequency characteristic diagram of the same diaphragm and a conventional diaphragm, and Figure 11 is a diagram of a speaker incorporating the same diaphragm. The plan view and FIG. 12 are sectional views of the main parts thereof. 4... Heartwood, 4,4''... Uneven ribs, 5,
5'...Surface material, 7...Small hole, 8,10...Small hole.

Claims (1)

[Claims] 1. A thermoplastic resin film is press-molded to provide radial uneven ribs to simultaneously improve the longitudinal and lateral strength of the diaphragm, and a flat core material with flanges on the outer periphery has high elasticity on both sides. A rectangular flat diaphragm for a speaker, which has a surface material attached thereto, and is provided with small holes for drying an adhesive for attaching the surface material to the flat core material.