JPS5888998A - Composite diaphragm - Google Patents

Abstract

PURPOSE:To obtain a composite diaphragm with light weight and large rigidity, by bonding a surface member at the external surface of the end of a projection and that of a recessed part of a plate core member where the projections and recessed parts of frustum of triangular pyramid are regularly formed with a prescribed relation. CONSTITUTION:In a core member 11, a lot of the same size of projections 12 of frustum of regular triangular pyramid are arranged regularly with a prescribed arrangement, and a lot of recessed parts 13 of symmetrical shape as the projections 12, like the inversion of the projections 12 are arranged. The member 11 is a metal mold of shape corresponding to the arrangement of the projections 12 and the recessed parts 13, and the mold can be formed by pressing a light plate such as a sheet of paper and aluminum thin plate. An adhesives is applied to the external side of a regular triangular end 13s of the recessed parts 13, a surface member 14 is bonded, and the adhesives is applied to the external side of the end 13s of regular triangular shape of the recessed parts 13, a surface member 15 is bonded, the entire parts are made flat, allowing to obtain a diaphragm most suitable for the acoustic diaphragm of a speaker.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite diaphragm suitable for use as an acoustic diaphragm of a speaker, etc., and in particular, the core member to which the surface member is bonded is lightweight, has high rigidity, and has an extremely high rigidity. The present invention proposes an improved composite diaphragm having a structure that is easy to manufacture.

Acoustic diaphragms used in speakers must be lightweight;
In particular, it is required to have a certain degree of rigidity, to have isotropic mechanical properties in two-dimensional directions along the plate surface, and to be easy to manufacture. As a suitable diaphragm for such a speaker, a composite diaphragm with a sandwich structure in which a thin surface material called a skin material is bonded to both sides of a honeycomb core material has been proposed, but it has not been put into practical use. 5
, a composite diaphragm using this honeycomb core material usually has a structure as shown in FIG. Skin materials 1 and 3 each made of aluminum foil or the like are adhered to form a flat diaphragm as a whole. Normally, as shown in FIG. 2A, a large number of adhesive surfaces are provided on the core material and the opposing adhesive surfaces and 6 of the core materials adjacent to each other are arranged. The two core materials are bonded to each other with an adhesive, and therefore, the part of the structure shown in bold when viewed from the top in Figure B shows that the two core materials are glued together. The parts are glued together with adhesive. For this reason,
A considerable amount of adhesive is consumed in manufacturing the honeycomb core material 1, and the weight of the completed honeycomb core material t is relatively large as it is accompanied by the weight of the consumed adhesive. In addition, the production of the honeycomb core material 1 involves a number of steps that require high precision, such as processing, adhesion, and cutting of the core material V, and there is a disadvantage that production cannot be said to be easy. Furthermore, although the structural unit of the honeycomb core material l is a regular hexagonal prism, it is not easy to form each hexagonal prism accurately and uniformly.
It is easy for the honeycomb core material to have a distorted cross section or a tilted axis, and as a result, the strength of the honeycomb core material changes in such a region, and the finished honeycomb core material The rigidity is large in the direction along the bonding surfaces S and B, and small in the direction orthogonal to the bonding surfaces S and B, and has the disadvantage that it has anisotropic mechanical properties.

Therefore, a composite diaphragm constructed using such a honeycomb core material t has a relatively large weight and is undesirable as a flexible plate due to partial changes in strength.

Therefore, the present invention provides a composite diaphragm suitable for a speaker diaphragm, which is constructed using a new core member having a structure that does not have the inconveniences and drawbacks associated with honeycomb core materials, instead of honeycomb core materials. It is something. Embodiments of the present invention will be described below with reference to FIG. 3 and subsequent figures of the drawings.

FIG. 3 shows -[Fl'Th of the composite diaphragm according to the present invention, // is a core member, and a large number of convex parts /2 formed in the shape of an equilateral truncated pyramid have the same size and a predetermined shape. These convex portions l
A large number of concave portions 13 are formed surrounded by a plurality of adjacent concave portions 13, each having a shape symmetrical to the convex portion t2, which is similar to the inverted convex portion/2f.

Since the protrusions 12 and the recesses 13 are each shaped like a truncated pyramid, this core member // is made of a mold having a shape corresponding to the arrangement of the protrusions 12 and the recesses t3. It can be formed by pressing a lightweight plate material such as aluminum or aluminum thin plate. Then, the outer surface (upper surface) side (
Adhesive is applied to the diagonally shaded areas) to adhere the surface member /G', and the equilateral triangular end face parts /3. An adhesive is applied to the outer surface (lower surface) of the diaphragm and the surface member /k is adhered thereto, thereby forming a composite diaphragm having a flat plate shape as a whole.

FIG. 9 is a plan view of the above-mentioned core member //, and FIG. 5 is a sectional view taken along the line ■--■ in FIG. V.

As is clear from these figures, the truncated triangular pyramid-shaped convex portions 12 are regularly arranged at regular intervals, and the ridgelines of the three convex portions are located at the apex of each of the three adjacent bottom portions. They are arranged in combination with each other so that they gather at two points. Here, the equilateral triangle formed by the end surface portion 12s of the convex portion 12 having vertices a, b, and cf is a triangular pyramid whose base is an equilateral triangle having vertices A, B, and Ce formed by the base of the convex portion 12. Therefore, the triangle ab
The area of c is t/p of the area of triangle ABC.

Also, the point t where each ridge line of three adjacent convex parts l:l gathers
6 are the vertices a and A, b and B, and c of each of the above triangles,!
:C, each convex portion t2
The mutual spacing of is selected. By doing so, the concave portion 13 has a shape symmetrical to the convex portion t2, as if the convex portion /2i was inverted, and the end surface portion 138
The equilateral triangle formed by the end face of the convex portion 12 /2. It is said to be congruent with the equilateral triangle formed by .

Since the convex portions 12 and concave portions 13 of the core member // are arranged and formed as described above, the core member // is formed in a so-called symmetrical shape on the front and back, and the surface members /U and lS
The adhesion area for each can be made equal. Whether viewed from the front side or the back side, a large number of truncated triangular pyramid-shaped protrusions are arranged with adjacent ones and their bottom apexes interlocking with each other, so that one core member/l whole has a structure in which a set of three adjacent convex portions support each other, and has extremely high rigidity, and has isotropic mechanical properties.

FIG. 6 shows another example of the composite diaphragm according to the present invention. In this example as well, a large number of protrusions /2' shaped like truncated triangular pyramids are arranged on the core member //. A concave part /3' having four shapes symmetrical to the convex part /2' is formed and surrounded by a plurality of adjacent convex parts /2', but in this example, the convex part /2' Although the array ' is regular, it has a more complicated arrangement than the array in FIG. It should be noted that the core member // is molded by bunosing a single lightweight plate material, and that an adhesive is applied to the outer surface side (shaded area) of the end surface portion t28' of the convex portion /2' to form the surface member. /%( is adhered, and an adhesive is applied to the outer surface side of the end face part /3s' of the recessed part /3' and the surface member /1 is adhered to form a composite diaphragm having a flat plate shape as a whole. This is similar to the example shown in FIG.

In the core member // of this example, as is clear from the plan view of FIG. The convex portions /2' are arranged so that the ridge lines of ' are not concentrated at one point, but are shifted point-symmetrically. Other recesses/
The convex part /2' is just like the convex part t2/ inverted.
Each convex part has a symmetrical shape, and the equilateral triangle formed by the end face part 3s' is congruent with the equilateral triangle formed by the end face parts l,' of the convex part/2'. A mutual spacing of /2' is chosen, similar to the core members in the example of FIG. In this way, three adjacent convex parts/2'
By combining the lower apex parts of each,
Directionality in bending strength can be further eliminated, and the rigidity is greater than that of the core member in the row of FIG. 3, and mechanical isotropy can be further improved.

As explained above, the plate-shaped core member of the present invention can be manufactured extremely easily by molding a lightweight plate material, which is different from a honeycomb core material, by Bunos processing, and also Since no adhesive is required, the weight of the finished product can be reduced, and the truncated triangular pyramid-shaped convex portions and concave portions are regularly arranged in a predetermined relationship.
It has extremely high rigidity and has isotropic mechanical properties. Therefore, the composite diaphragm according to the present invention, which is obtained by using such a plate-shaped core member and bonding surface members to both sides thereof, is lightweight, has extremely high rigidity, and has two-dimensional vibration along the plate surface. It has mechanical properties that are isotropic in the direction,
Moreover, it can be manufactured extremely easily. Furthermore, since the surface member is adhered to the end faces of each of the many truncated triangular pyramid-shaped convex portions and recesses of the core member, the adhesion is extremely strong and there is no possibility of the surface member peeling off from the core member. There is also the advantage that the strength of the entire diaphragm is further increased. Therefore, the composite diaphragm according to the present invention is
In various aspects), it is superior to composite diaphragms using Nicum core materials, and is suitable for acoustic diaphragms used in speakers.

Note that the shape, arrangement, etc. of the triangular truncated pyramid-shaped convex portions and concave portions of the core member in the present invention are not limited to the above-mentioned embodiments, and other shapes, arrangements, etc. are possible without departing from the gist of the present invention. Of course, any arrangement may be used.

[Brief explanation of the drawing]

Figure 1 is a partially cutaway perspective view showing a composite diaphragm using a conventional honeycomb core material, Figure 2 is a diagram used to explain the honeycomb core material, and Figure 3 is a diagram showing a composite diaphragm according to the present invention. FIG. 5 is a partially cutaway perspective view showing an example, FIG. 5 is a plan view showing the core member in the example of FIG. FIG. 7 is a partially cutaway perspective view showing another example of the composite diaphragm according to the present invention, and FIG. 7 is a plan view showing the core member in the example of FIG. 6. In the figure, // is a core member, 12 and /2' are convex parts, 13 and /3' are concave parts, /2s, /28', /J8 and 138' are end face parts, and llI and /& are surface members. be. II 12 13
15Figure 4Figure 513 13s 13 13s

Claims (1)

[Claims] Each is formed in the shape of a truncated triangular pyramid, and each of the protrusions is surrounded by a number of regularly arranged protrusions with the bottom vertices of adjacent ones interlaced with each other, and each is surrounded by a plurality of adjacent protrusions among the protrusions. A number of concave portions each having a shape symmetrical to the convex portion, which is an inverted version of the convex portion, are formed on the outer surface side of the end face portion of the convex portion of the formed plate-shaped core member, respectively. A composite diaphragm comprising a surface member adhered to the outer surface of the end surface of the recess.