JPS59152796A - Diaphragm for speaker - Google Patents

Abstract

PURPOSE:To obtain a product excellent in high rigidity by forming to corrugate a thermoplastic resin film or a metallic foil by the processing method such as vacuum forming and sticking a surface member on both front and rear sides of a core member having ruggedness on wall faces of each waved part. CONSTITUTION:A rugged rib 2(4) reinfocing the wall face is provided to each corrugate part of the core member formed to corrugate by applying vacuum forming, compression molding or press forming to the thermoplastic resin film or the metallic foil 1(3). The rib 2(4) is processed at the same time when the core member is formed in the form of wave. A flat diaphragm 6 is formed by sticking a surface member 5 to the core member 1(3). Thus, the light weight' diaphragm capable of reproducing high sound frequencies with high rigidity and suppressing split vibration is manufactured.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a diaphragm for a speaker.

Construction of conventional examples and their problems Most conventional speaker diaphragms are made by molding paper pulp, and cone-shaped diaphragms are common.

As a result, the sound source positions shift between the inner and outer peripheries of the diaphragm, resulting in a phase difference, making it difficult to obtain a speaker with flat frequency characteristics.

On the other hand, a flat speaker with a flat diaphragm allows sound source positions to be aligned, which is advantageous in achieving flattened frequency characteristics. However, in the case of flat speakers,
When conventional paper is used, its rigidity against bending is low, so split vibrations tend to occur, making it impossible to obtain flat frequency characteristics over a wide band.

Therefore, one idea is to construct a flat plate diaphragm having a sandwich inch structure that provides high bending rigidity.

Conventionally, there are flat plate diaphragms that use aluminum honeycomb for the core material, but the processing process is very complicated and the manufacturing cost is significantly higher than that of conventional paper diaphragms. It has the disadvantage of being expensive. On the other hand, it is also possible to use a core material made by vacuum forming, pressure forming, or press forming a thermoplastic resin film or a metal foil.
In this case, although it is advantageous in terms of cost compared to using aluminum honeycomb as the core material, it has the disadvantage that the reproduction band is narrower than when using aluminum honeycomb.

OBJECTS OF THE INVENTION The present invention eliminates the drawbacks of the conventional diaphragms mentioned above, and provides a diaphragm for a speaker that is easy to manufacture and can realize flat frequency characteristics over a wide band.

Structure of the Invention The present invention provides unevenness on the wall surface of each wavy portion of a core material formed into a wave shape by vacuum forming, pressure forming or press forming a thermoplastic resin film or metal foil, and the rigidity of the wall surface is strengthened by the unevenness. It's just something you do. In this way, the frequency characteristics can be flattened over a wide range by increasing the rigidity of the core material, and the above-mentioned irregularities can be provided at the same time during the core material molding process, which facilitates the manufacturing itself.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 shows a part of the core material in one embodiment of the present invention. In FIG. 1, 1 is a core material formed by pressure forming a thermoplastic film into a wavy shape, and 2 is a core material 10.
These are reinforcing ribs provided in an uneven shape to strengthen the wall surface of the wavy portion. Note that the reinforcing lip 2 can be added at the same time as the core material 1 is formed by machining irregularities on the wall surface of the mold.

Moreover, FIG. 2 shows a cross section of a core material formed by press-molding a thermoplastic film. 3 is a core material, and 4 is a rib provided to strengthen the wall surface of the corrugated portion of the core material 30.

FIG. 3 shows the frequency characteristics and strain characteristics of a flat diaphragm obtained by pasting a surface material (not shown) on the surfaces of the core materials 1 and 3 shown in FIGS. 1 and 2. The broken lines Af and Ad are the frequency characteristics and strain characteristics when there are no reinforcing ribs on the wall surface, and the solid line Bf
, Bd are the frequency characteristics and strain characteristics when the reinforcing ribs 2 and 4 are provided on the wall surface.

As described above, according to the above embodiment, the reinforcing rib unevenness 2, 4 is provided on the wall surface of the core materials 1, 3 to strengthen the rigidity of the wall surface, compared to that using a conventional thermoplastic resin film. The playback band can be greatly expanded.

The shape of the reinforcing ribs on the wall of the heartwood is triangular.

Possible shapes include rhombus, cross, and single-letter shapes, various arrangement methods such as radial, and various sizes, but these can be selected appropriately according to the characteristics of the speaker actually designed. . The material of the core material may be changed depending on the molding conditions and method, but if metal foil such as aluminum foil is used, the effect will be even more remarkable, making it possible to reproduce high-pitched sounds and expand the area.

Effects of the Invention As described above, the speaker diaphragm according to the present invention has the following effects.

(1) Since the diaphragm rigidity is increased, the treble reproduction range can be expanded.

(2) Since the rigidity of the diaphragm is increased, split vibration can be suppressed and low distortion can be achieved.

(3) The rigidity of the diaphragm is increased and the thickness of the core material can be made thinner by that amount, so the weight of the entire diaphragm can be reduced and efficiency can be increased.

(4) It is inexpensive because the magnet can be made smaller by the increase in efficiency.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a part of the core material of a speaker diaphragm according to an embodiment of the present invention, FIG. 2 is a sectional view of the core material of a speaker diaphragm according to another embodiment of the present invention, and FIG. FIG. 2 is a sound pressure frequency characteristic diagram and a distortion characteristic diagram of a speaker using a conventional diaphragm and a conventional speaker. 1.3... Heartwood, 2,4... Ribs for reinforcing the heartwood wall ○ Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3

Claims (1)

[Claims] A diaphragm for speakers made of a thermoplastic resin film or metal foil that is vacuum-formed, pressure-formed or press-molded to form a wave shape, and surface materials are pasted on both the front and back sides of a core material with unevenness on the wall surface of each wave-like part. .