JPS58182399A - Diaphragm for speaker - Google Patents

Abstract

PURPOSE:To obtain a diaphragm with excellent reliability, by providing a flat part along the outer circumference of a core member and increasing the bonding strength with a surface member. CONSTITUTION:In figure, 11 is a core member made of a thermoplastic resin film incorporated with a ring groove at the outer circumference, 13, 14 are surface members bonded on both sides of the member 11 together with the ring groove 12. The core member 11 is provided with a projection rib 15 having L1 length radially at an interval of 90 deg. and a projection rib 16 having L2 length, shorter than the L1 radially is provided between the ribs 15 at an interval of 30 deg.. A projection rib 17 having L3 shorter length is provided between the ribs 15 and 16, and between the ribs 16 at an interval of 15 deg. radially, and further, a projecting rib 18 having L4 length is provided. The outer circumference of the core member 11 having the ribs 15-18 is provided with the ring groove 12 made of U-shaped groove.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speaker diaphragm, and its purpose is to increase the adhesive strength with the surface material by providing a flat portion on the outer periphery of the core material. To provide a diaphragm for a speaker which is capable of high reliability and has excellent reliability.

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

Therefore, there is a nine phase difference between the inner and outer circumferential parts of the speaker diaphragm in which the sound source positions are different, making it difficult to obtain a speaker with flat frequency characteristics.

On the other hand, speakers with a flat diaphragm do not have the front chamber effect seen in cone-shaped speakers, and are advantageous in flattening the frequency response. When used as a core material, it has the disadvantage that it has low bending rigidity and is prone to splitting vibrations, making it difficult to obtain flat characteristics over a wide band.

Therefore, in order to increase the bending rigidity of a flat plate, a sand inch structure is being considered. Up until now, many diaphragms have been used that use a sandwich structure with aluminum honeycomb as the core material, but aluminum as a sandwich structure...
Because the manufacturing process of Nikam is complicated, the cost is high, and it is difficult to apply it as a speaker for popular stereo equipment, radio receivers, television receivers, etc. In addition, because the core material is made of metal foil (20-3011) such as aluminum, the adhesion area with the surface material is small and the adhesion strength is weak, especially the outer periphery where the edges are bonded. Because large stress is applied to the diaphragm at the outer periphery of the diaphragm, conventional No-Ni-Cam uses treatments such as a fillet structure to increase adhesive strength and the use of a large amount of adhesive only on the outer periphery, which also increases costs. Ta. In addition, as shown in Figure 1, in the Nikum diaphragm, since the surface materials 2 and 3 are bonded to both sides of the Nikum core material 10, there is a free end portion on the outer periphery, which causes resonance and abnormalities. Sound may be generated, and therefore, the ends of the surface materials 2 and 3 are bent to increase their strength to prevent the generation of abnormal noise, but this also causes an increase in cost.

The present invention solves these conventional drawbacks,
A core material in which a thermoplastic resin film is formed into a core material having an arbitrary shape having a large number of irregularities by vacuum, pressure-air, or vacuum-pressure forming, and at least one ring groove is formed on the outermost periphery of the core material, and this ring groove is provided. A surface material is bonded to the surface of the ring including the ring groove. According to this structure, the core material can be molded in one step by molding the thermoplastic resin film in vacuum, pressure, or vacuum pressure, thereby reducing costs, and forming a concave ring around the entire outer periphery of the core material. Since a flat portion can be provided by forming the groove portion, the adhesive strength with the surface material can be increased. Furthermore, since the concave ring grooves form the outer wall, unlike a honeycomb core material, free cavities are not formed on the outer periphery, and there is an advantage that distortion or abnormal noise due to resonance does not occur.

The present invention will be described below with reference to drawings of embodiments.

FIG. 2 shows an embodiment of the invention. In the figure, 11 is a core made of a thermoplastic resin film having a ring groove 12 on the outer periphery; The surface material including the ring groove portion 12 is bonded with an adhesive. As shown in FIG. 3, the core material 11 is provided with convex lips 16 having a length Ll at 900 intervals in the radial direction. A convex 1J fiber 17 having a length L3 shorter than the length L1+L2 of the convex lip 15, which is shorter than the length L1 of the convex lip 15 and a shorter length L2, is provided, and the convex ribs 15, 16. 1
The above-mentioned convex shape 1 is arranged in the radial direction at intervals of 7.5° between the grooves n of 7.
The knobs 15, 16, and 1 are provided with a convex lip 18 having a length L4 equal to the length L1+2+L5.

A ring-shaped groove portion 12 made of a U-shaped groove is provided on the outer periphery of the core material 11 having the above-mentioned convex lips 15, 16, 17, and 18.

Specifically, a polyarylate resin film (U polymer ■, Unitika ■fA) with a thickness of 150 μm was heated to about 3 so'c to soften it, and then vacuum formed into an uneven shape having a ring groove 12 on the outer periphery as shown in FIG. A core material 11 was formed. At this time, the core material 11 has a radius of 37 fl, and the convex lip 15. 16. Each length Lll L2 of 17°18
+ L5 + L4 = 36 mW, 31
．． 5ff, 26M, and 12fl, the width was 3mm, and the depth and height were 3jnl. The ring groove 11 on the outer periphery had a depth of 3ff, a width of 2mm, and a core material with a radius of 4Qn as a whole. 38 pieces of aluminum having a thickness of 30 μm were bonded to both sides of the core material 11b as surface materials 13 and 14 using a polyester film adhesive under heat and pressure to obtain a squawker diaphragm having a diameter of 80 Nap and a thickness of 3111 mm. The peel strength of the surface material at this time was measured and found to be 3.1 kg/cm. This is a conventional alumino-Nicam diaphragm (with a squawker with a diameter of 801ff).The shape of the Tsuta-Nicam cell is 1D - 3 sides, hexagonal with 3 shoulders, and the core material is 1 mm.
(20 μm) 3s material, height 3wN, and the same polyester film adhesive was used as the adhesive. ) has a peel strength approximately twice that of the surface material of 1.4 kq/C1l.

As described in detail above, according to the present invention, the adhesive strength between the surface material and the core material at the outer peripheral part of the diaphragm, which is the part where the edges are bonded, is much stronger and more reliable than that of conventional alumino-Nicum diaphragms. This is a diaphragm for speakers with high performance. Furthermore, the outer periphery of the diaphragm is sealed due to the ring groove, and there is no void created by hexagonal cells like in conventional Nikum diaphragms, so distortion due to cavity resonance or the outer edge of the diaphragm is sealed. This has the advantage that no abnormal noise is generated due to partial resonance of the surface material.

Incidentally, the uneven pattern of the core material 11 in the outer circumferential groove portion 12 has a circular shape other than the shape shown in the example.

Hexagons, quadrilaterals, triangles, ellipses, etc. can be considered, and various ways of arranging them such as concentric circles, radial shapes, etc. can be considered, but none.
A similar effect can also be obtained.

Furthermore, the thickness of the diaphragm can also be applied to smaller tweeters and even larger woofers, and the shape of the diaphragm is not limited to circular, but may be rectangular.

It goes without saying that the thickness of the JCt material may be changed depending on the required acoustic characteristics, or other thermoplastic resins may be used.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view of a conventional speaker diaphragm, Fig. 2 is a sectional view showing an embodiment of the speaker diaphragm of the present invention, and Fig. 3 is a main part of the core material used in the same diaphragm. FIG. 11... Heart material, 12... Ring groove,
13.14... Surface material. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 1.5

Claims (1)

[Claims] A core material formed by vacuum forming, pressure forming, or vacuum pressure forming a thermoplastic resin film has a large number of uneven shapes in the center and a ring groove on the outer periphery, and the surface of the core material includes the ring groove. A speaker diaphragm made of pasted materials.