JPS6216063Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a diaphragm for a speaker having a three-layer structure.

The characteristics required for a speaker diaphragm are specific elastic modulus E/ρ (E: elastic modulus, ρ: density)
is large and has a moderate internal loss. Recently, honeycomb structured diaphragms have been used to satisfy these requirements. This product uses rectangular aluminum thin plates as the core material of the honeycomb, overlaps them and glues parts alternately, and stretches them to form a so-called honeycomb structure.This material is used as the core material of the diaphragm, and both sides are covered with CFRP (carbon fiber). It has a three-layer structure in cross section by laminating skin materials made of reinforced plastic, etc., and has a specific elastic modulus E/ρ of 5 compared to a diaphragm made from wood cellulose fiber. ~Ten
An excellent diaphragm with almost the same internal loss can be obtained. However, the core material of this honeycomb diaphragm is made into a honeycomb structure during manufacturing.
The diaphragm shape of the annular speaker must be made by cutting a large honeycomb board by punching, etc., and the end face remains a thin plate end face, and the voice attached to the inner circumferential edge is in contact with the thin plate end face with a small area. In addition, the skin material that is bonded to both sides comes into contact with the edges, making it difficult to obtain a sufficient bonding area and causing poor adhesion.This poor adhesion may cause disturbances in frequency characteristics or damage. There were flaws.

This invention is an attempt to provide a speaker diaphragm that overcomes these drawbacks.

An embodiment of this invention will be described below with reference to the drawings.

In FIGS. 1 to 3, reference numeral 1 indicates the entire speaker diaphragm, which is usually formed in an annular shape and has a cone shape protruding outward toward the front. Reference numeral 2 denotes a voice coil fixed to the inner peripheral end of this diaphragm with adhesive or the like. Further, an edge (not shown) is fixed to the outer peripheral end of the diaphragm. 3 is a metal plate with high thermal conductivity such as aluminum, or a flat thin plate material such as metal foil, which is pressed or drawn by vacuum forming, etc., so that its planar shape becomes circular and has a uniform height t from the bottom surface 9, and the tip part 8 The protrusion 4 is formed to have a flat surface, and the inner peripheral end to which the voice coil 2 is attached has the same shape as the outer periphery of the voice coil and is formed at the same height as the height t of the protrusion. This is a core material of a speaker diaphragm having a bent portion 5 formed therein and having an annular shape similar to that of the diaphragm 1 . 6 and 7 are skin materials pasted with adhesive to sandwich the core material, that is, sandwiching the protrusion tip 8 and bottom surface 9 of the core material 3, and are made of CFRP (carbon fiber reinforced plastic). )
Alternatively, it is made of sheet-like material such as GFRP (glass fiber reinforced plastics) and is formed into an annular shape similar to the shape of a diaphragm. Further, the tip portion 8 of the protrusion is formed to be flat as shown in the drawing. In this way, the speaker diaphragm 1 has a three-layer structure consisting of the skin material 6, the core material 3 with a constant height t, and the skin material 7, but the skin materials 6 and 7 are attached to the core material 3 with adhesive. When wearing skin material 6,7
is joined to the flat part of the tip 8 of the protrusion of the core material 3 and the bottom surface 9, and the adhesion area is significantly increased due to surface-to-surface contact compared to the conventional contact between the end surfaces of thin plates. The adhesive strength with 6 and 7 is significantly improved. Further, even if the thickness t is obtained by the protrusions 4, the material volume is small and there is internal loss, and it is possible to obtain the specific elastic modulus E/ρ and internal loss equivalent to those of the conventional honeycomb core. Furthermore, the core material 3 has a bent portion 5.
As shown in FIG. 3, the voice coil 2 makes surface contact with the bobbin, increasing the bonding area and improving the bonding strength.

In the above embodiments, the shape of the protrusion of the core material is circular, but it is also possible to have a polygonal shape such as a triangle or square, and the shape of the diaphragm is not limited to a cone shape but may also be a flat plate shape. Of course.

As described above, the speaker diaphragm of this invention has a plurality of projections each having a flat tip as a core material, and the skin material is adhesively fixed to both sides by sandwiching the tip and bottom of the core material. , since it constitutes a diaphragm, it has the same good properties as a honeycomb structure diaphragm in terms of specific elastic modulus E/ρ and internal loss, and also eliminates the disadvantages of a conventional honeycomb structure diaphragm, such as the core, skin, and core. The bonding area between the voice coil bobbin and the voice coil bobbin can be increased due to surface-to-surface contact, and there is no bonding defect at practical strength, resulting in a good speaker diaphragm that does not cause abnormal noise or damage. It is something that

[Brief explanation of the drawing]

The drawings show an embodiment of this invention, with FIG. 1 being a plan view, FIG. 2 being a sectional view, and FIG. 3 being a vertical sectional view with a voice coil attached. In the figure, 1 is a diaphragm of a speaker, 2 is a voice coil, 3 is a core material, 4 is a projection, 5 is a bent part, 6 and 7 are skin materials, 8 is a tip, and 9 is a bottom surface. Note that the same reference numerals in the figures represent the same parts.

Claims (1)

[Claims for Utility Model Registration] (1) A core material 3 and skin materials 6 and 7 bonded to both sides of this core material to form a three-layer structure, formed into an annular shape, and a voice coil 2 attached to the inner peripheral end. In the diaphragm of the speaker, a flat plate of a metal plate or metal foil with high thermal conductivity is used as the core material, and a large number of protrusions 4 having a desired height are formed on one side of the flat plate. A core member 3 is formed by forming a bent portion 5 having the same shape as the outer diameter of the voice coil 2 and having the same bending height as the protruding portion 4 at the inner peripheral end where the voice coil is attached; This speaker diaphragm is characterized by having a three-layer structure in which the tip 8 of the protrusion of the core material and the bottom surface 9 are tightly bonded and fixed by skin materials 6 and 7. (2) The speaker diaphragm according to claim 1, in which the protruding portion 4 and the bent portion 5 at the inner peripheral end are formed by a draw die.