JPS60177797A - Diaphragm for speaker - Google Patents

Abstract

PURPOSE:To increase resonance frequency by giving directivity to rigidity of a diaphragm and by arranging skillfully the directivity. CONSTITUTION:A broken line in the figure shows a resonance mode to disturb coaxial sound pressure. A core 11 of a diaphragm is constituted of a high polymer sheet with a zigzag sectional shape, and its pattern is arranged so that its ridgeline will be orthogonal with respect to nodes of the 1st-3rd resonance. An approximately square flat diaphragm is adhered to a surface member made of a thin foil whose both sides are made of Al, etc., of the core 11. With such a constitution, the rigidity of the entire diaphragm becomes stronger in the orthogonal direction with respect to a resonance mode and resonance frequency with respect to each resonance mode is made higher.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a diaphragm for a speaker, and in particular uses a Santoy-Sochi groove structure consisting of a core material and a surface material fixed to both sides, and its rigidity is partially reduced. By increasing the
This invention relates to a speaker diaphragm with increased resonance frequency.

Conventional configurations and their problems Normally, it is ideal for the diaphragm of a speaker to vibrate as a piston over the frequency band used. For example, if the diaphragm deforms during vibration or split vibration occurs, the sound pressure will increase. Frequency characteristics, distortion rate, and phase characteristics deteriorate, impeding high-fidelity reproduction. In order to solve these problems (4), in recent years, flat plate diaphragms using honeycomb sanatorium-rich structures, etc. have been adopted.By the way, in many speakers, the A so-called nodal drive method is used to apply a driving force to the section of the drum and prevent the occurrence of this first-order resonance, and the higher the basic first-order resonance frequency is, the wider the playback band is, which is advantageous. Needless to say.

Hereinafter, a conventional flat diaphragm for speakers will be explained based on the drawings. In FIG. 1, (1) is a core material made of a polymer sheet having a zigzag cross section, and surface materials (2) are fixed to both sides of the core material. Moreover, the zigzag-like arrangement of the cross section of this core material (1) is arranged parallel to one direction, as shown in FIG.

As described above, since the core material has directionality, it has the disadvantage that the rigidity is reduced and the resonant frequency is lowered. This will be explained using the cantilever beam shown in FIGS. 3 and 4. Figure 3 shows a cantilever beam in which the zigzag direction of the core material, that is, the ridgeline of the core material is aligned with the long side of the beam.
A diaphragm) is shown, and FIG. 4 shows a cantilever beam in which the ridgeline of the core is parallel to the short side of the beam.

The second resonance where one node of such a cantilever occurs
If the core material is a homogeneous material, the curve will be as shown by the dotted line in FIG. The knot occurs in the direction of the short side at the location marked N in the figure, and is perpendicular to the direction of the long side. Therefore, the structure shown in FIG. 3 has high rigidity in the direction perpendicular to the nodes, and the structure shown in FIG. 4 has high rigidity in the direction parallel to the nodes. When the resonance frequency in the cases shown in Figs. 3 and 4 is calculated using the finite element method, it is 1700 Hz in the case of Fig. 3 and 100 Hz in the case of Fig. 4.
It was hot at Hz. The shape and dimensions of the cantilever beam (diaphragm) are length 10a, width 8cm, height 1am, and core material width 1σ.

The calculations were made assuming that the thickness of the core material was 20 μm and the thickness of the surface material was 50 μm, and the case where aluminum was used as the material for the core material and the surface material was calculated. In this way, when the intensity is high in the direction orthogonal to the resonance top-tono node, the resonance frequency is high, and in the opposite case, it is low. Therefore, in the case of the flat plate diaphragm shown in Fig. 1,
Although it is strong in one direction, it is weak in the opposite direction, which has a disadvantage in that it has an adverse effect on the resonant frequency and lowers the resonant frequency.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and provides a diaphragm for a speaker in which the resonance frequency is increased by giving directionality to the rigidity of the diaphragm and arranging the directionality well. With the goal.

Structure of the Invention In order to achieve the above-mentioned object, the speaker diaphragm of the present invention is a substantially rectangular flat plate diaphragm constructed from a Santoy-Sochi groove structure in which surface materials are fixed to both sides of a core material. The rigidity of the plate is increased in the direction perpendicular to the resonant upper node.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 6th
The figure shows the core material of a speaker diaphragm. FIG. 7 shows the resonance mode of a substantially rectangular flat diaphragm, and the dotted line in FIG. 6 overwrites this resonance mode. Figure 8 fa) is a plan view of the first resonance mode, (b)
[The same perspective view, FIG. 9(a) is a plan view of the second-order resonance mode, (b) is the same perspective view, FIG. 10(a) is a plan view of the third-order resonance mode, fb) It is the same perspective view. Note that FIG. 7 is a combination of the above-mentioned FIGS. 8 to 10. In addition to this resonant t-do, there is a resonant t-do that passes through the center and is divided by line segments on the diaphragm surface, but since it is symmetrical about the central axis, it is a circular voice whose rotation center is the diaphragm center. If driven by a coil, these resonance tops will not appear. Therefore, the resonant upper cord that disturbs the axial sound pressure is the resonant upper cord shown in FIGS. 8 to 10. By the way, the core material (11) shown in FIG. 6 is made of a polymer sheet with a zigzag cross-sectional shape. It is arranged in a direction perpendicular to the next resonance node. And, the substantially rectangular flat plate diaphragm @ according to the present invention is
As shown in FIG. 11, a surface material α9 made of thin foil such as aluminum or titanium foil is fixed to both sides of the core material o1).

According to the above configuration, since the zigzag pattern of the core material 01) is arranged in a direction perpendicular to the resonance top, the rigidity of the entire diaphragm is lower than the resonance top. It is stronger in the right angle direction.

Therefore, for the node of the first resonant station wave number, the second
Also, it is difficult to deform with respect to the nodes at the time of third-order resonance (because the rigidity is increased, the resonant frequency is increased for each resonant t-do, as explained in the conventional example).

Next, another embodiment will be described based on FIG. 12.

The substantially rectangular flat plate diaphragm (2) in this other embodiment is as follows:
A surface material α3 made of aluminum foil or titanium foil is fixed to both sides of a core material (11) made of a homogeneous material such as polystyrene foam or polyurethane, and at least one surface of this surface material α is subjected to vibration. In other words, a large number of reinforcing materials Q4) are fixed in a direction perpendicular to the nodes of the first to third resonance modes to increase the rigidity of the plate. The reinforcing material is preferably a hollow cylinder or bar made of aluminum titanium or rag. Furthermore, instead of providing a reinforcing material, the core material may not be homogeneous, but a core material blended to increase the rigidity in the direction orthogonal to the joints of the resonant t-do may be used.

Effects of the Invention According to the groove bottom of the present invention, the rigidity of the diaphragm is increased, so the resonant frequency is increased, and therefore, when used as a diaphragm for heel force, the histosis region is expanded and the sound pressure frequency characteristics are flattened. The useful band becomes wider.

[Brief explanation of the drawing]

Figures 1 to 5 show conventional examples. Figure 1 is a perspective view of a substantially rectangular flat plate diaphragm, Figure 2 is a perspective view of the core material, and Figures 3 to 5 are cantilever beams. Diagram explaining intensity comparison,
FIG. 6 is a diagram showing the layout of the core material according to the third embodiment of the present invention, FIGS. FIG. 12 is a perspective view of a substantially rectangular flat diaphragm according to one embodiment, and FIG. 12 is a perspective view of another practical example. OD... Core material, (2) - Diaphragm, 03... Surface material, (
14) Reinforcement agent Yoshihiro Morimoto Figure 1 Figure 2 Figure 3 Figure 4 Figure 7 Figure 7

Claims (1)

[Scope of Claims] (1) A substantially rectangular flat plate diaphragm constituted by a Sashitoi-Sochi structure in which surface materials are fixed to both sides of a core material, wherein the rigidity of the core material is adjusted with respect to the resonance upper node. A diaphragm for a single seat raised in the orthogonal direction. 2. A diaphragm for a speaker according to claim 1, wherein a reinforcing material is provided on the surface material in a direction orthogonal to the node of the resonant upper chord in order to increase the rigidity of the diaphragm. 3. The speaker diaphragm according to claim 1, wherein the direction in which the material stiffness of the core material is high is aligned with the direction perpendicular to the nodes of the resonance mode.