JPS6038076B2 - Diaphragm for speaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speaker diaphragm having a sandwich structure in which a tape-shaped core material is sandwiched and bonded between surface materials. The present invention provides a speaker diaphragm that can flatten the frequency characteristics or reduce the temperature rise of the voice coil during large inputs, and improve the input resistance characteristics.

An embodiment of the present invention will be described below with reference to FIG.

In Figure 1, 1 and 1' are circular surface materials made of metal foil such as aluminum or titanium or plastic film such as polyester or polyvinyl chloride, and 2 is a metal foil such as aluminum or titanium or polyester or polyvinyl chloride. It is a tape-shaped core material made of plastic film, etc.

The core material 2 is interposed between the surface materials 1 and 1' so as to be perpendicular to the surfaces of the surface materials 1 and 1'. The tape-shaped core material 2 is directed from the center side of the surface materials 1, 1' toward the outer circumferential side, is folded back on the outer circumferential side, and is directed toward the center side, then further toward the outer circumferential side, etc. in a radial shape. It is placed in a folded position. Note that the outer bent portions A are all located on a circle with approximately the same diameter, whereas the inner bent portions have a bent portion B that reaches near the center of the surface materials 1 and 1', and a circle with approximately the same diameter. In this embodiment, two bent portions B' are formed between the bent portions B. Note that the tape-shaped core material 2 and the surface materials 1, 1' are bonded together. In this way, a flat plate diaphragm 3 having a sandwich structure in which the core material 2 is sandwiched between the surface materials 1 and 1' is obtained. In the embodiment shown in FIG. 1, the amount of core material 2 is larger on the outer peripheral side of the diaphragm 3 than on the central side, and the areal density (diaphragm weight per unit area) is larger on the outer peripheral side. Become.

In FIG. 1, b indicates the position of the nodal line when the diaphragm resonates in this embodiment, and a indicates the position of the nodal line when the surface density on the outer and inner circumferential sides of the diaphragm is constant. Compared to a diaphragm with a constant areal density, in a diaphragm like this example where the areal density is greater on the outer periphery side than on the center side, the position of the nodal line is closer to the outer periphery. It is something.

Figures 2A and BI respectively show the vibration mode A of the diaphragm with a constant areal density and the vibration mode B of the diaphragm of this example in which the areal density on the outer peripheral side is larger than the areal density on the center side. In case A, the diameter of the nodal circle is 0.
67 legs, whereas in the case of this embodiment of B, there are 067 legs.
It is even larger than the skin, and due to nodal vibration, coil bobbin 4 and voice coil 5 are larger in B than in A.
The diameter of the speaker is increased, and the input resistance of the speaker is improved.

One of the factors that determines the input resistance of a speaker is the destruction of the voice coil due to temperature rise when a large input is applied.

The temperature rise of the voice coil for the same electrical input decreases as the voice coil diameter increases, and a speaker using a diaphragm with a large voice coil diameter as in this embodiment has excellent input resistance characteristics. As mentioned above, the first
In the example shown in the figure, the areal density on the outer circumferential side of the diaphragm can be increased and the position of the node line can be moved to the outer circumferential side, so a speaker with excellent input resistance characteristics can be obtained without increasing the diameter of the diaphragm. It is something.

FIG. 3 shows another embodiment of the invention.

In this embodiment, the center-side bent portions C of the core material 2 are aligned approximately on the same circle, and the outer-periphery side bent portions D and D' are located on the outer periphery side and at the intermediate portion. According to this embodiment, the areal density on the center side of the diaphragm can be made larger than on the outer peripheral side, and the nodal line position is made closer to the center than the nodal line position of a diaphragm with a constant areal density. Therefore, the diameter of the voice coil for nodal line drive can be made small, and therefore the magnetic circuit becomes 4-type and inexpensive. Furthermore, according to this embodiment, when using a voice coil with the same diameter as that of a diaphragm with a constant areal density,
As the diaphragm diameter becomes larger and the diaphragm area becomes larger,
This improves the efficiency of the speaker. As described above, according to the present invention, the areal density on the center side and the outer peripheral side of the diaphragm can be easily changed, and the nodal line position can be changed arbitrarily.
It is possible to improve the input resistance characteristics of the speaker, or to miniaturize the magnetic circuit and improve the efficiency.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a part of a speaker diaphragm according to an embodiment of the present invention with a cutaway, and FIGS. 2A and 2B are a conventional speaker diaphragm with a constant areal density and FIG. 3 shows the vibration state of the speaker diaphragm of the present invention.
The figure is a partially cutaway perspective view of another embodiment of the present invention. 1, 1'... Surface material, 2... Heart material, 3
...Diaphragm, 4...Coil bobbin, 5...Voice coil Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. In a speaker diaphragm with a sanderch structure, in which a tape-shaped core material is bent alternately on the center side and the outer peripheral side of a surface material to form a radial shape, and a surface material is bonded to both sides of this radial core material. A diaphragm for a speaker, characterized in that the position of the bent portion on the center side or the outer circumferential side of the core material is changed once or every multiple times to change the surface density between the center side and the outer circumferential side.