JPS62180699A - Diaphragm for acoustic device - Google Patents

Abstract

PURPOSE:To obtain a diaphragm having a much more internal loss with a dedicated cost, and with good workability without damaging lightness and highly bending rigidity, by constituting a honeycomb core material with a foil formed with a non-magnetic compound type vibrationproof alloy. CONSTITUTION:A honeycomb core material 1a formed with the non-magnetic compound type vibrationproof alloy is used, and skin materials 2 and 3 are stuck at the both planes of a honeycomb structured body 1 with a sticking agent 4. It is possible to improve remarkably the internal loss in the whole of the diaphragm by the usage of a compound type vibrationproof alloy. The comparative elastic modulus E/rho of the honeycomb core material is not inferior compared with that of an aluminium having a superior quality as a core material, and it is possible to lighten the diaphragm equally in an aluminium case because the foil can be made thinner than an aluminium foil considering a tensile strength. Also, it is no more necessary to perform a process to have the internal loss on the skin material (the process reduces the comparative elastic modulus of the skin material as a result) in order to get the internal loss for whole of the diaphragm. Especially, the reduction of a cell resonance generated in a high-pass reproducing frequency can be produced as a big affect.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a diaphragm (ζ) for an acoustic device made of a honeycomb structure.

[Conventional technology]

Generally, a diaphragm for an acoustic device made of a honeycomb structure is
As shown in Fig. 4, a skin material (2+,
, f3) are attached with adhesive (4).

Furthermore, as shown in FIG. 2, there is also a structure in which each core (1a) of the honeycomb structure (1) is filled with foamed resin (5).

By the way, a diaphragm for audio equipment (hereinafter referred to as a diaphragm)
As such, it is generally required that the specific elastic modulus E/ρ, bending rigidity E·■, and internal loss η be large. Here, E
is the Young's modulus, ρ is the density, and ■ is the second order mor of the cross section, Menoto. Here, the larger the specific elastic modulus E/ρ, the higher the limit resonance frequency and the wider the reproduction frequency band. In addition, the larger the bending stiffness E・■, the lower the distortion, and the larger the internal loss η, the sharper the mechanical resonance, i.e., the Q value, which flattens the characteristics and improves vibration quality. Get a board.

Conventionally, a honeycomb structure has been adopted as a diaphragm from this point of view. The bending rigidity E・■ is proportional to the cube of the thickness of the diaphragm, but if you use a honeycomb structure, there is almost no increase in weight (even if it is thick, it is almost hollow, and the core material occupied by the diaphragm is The weight can be increased by approximately 0 to 20% without significantly affecting the weight of the diaphragm. For example, if the thickness is doubled, the bending stiffness E-
I becomes 8 times. In order to increase the specific modulus of elasticity E/ρ, a skin material having a high green rate is usually used.

[Problem that the invention seeks to solve]

Since the conventional diaphragm is constructed as described above, the skin material with a large specific elastic modulus E/ρ has a very small internal loss l, and the internal loss of the entire diaphragm is also small, resulting in a peak frequency characteristic. There was a problem in that dips occurred and good characteristics could not be obtained. Furthermore, filling the core increases the weight, and the light weight and high efficiency characteristic of the original honeycomb structure specification is lost. Furthermore, considering the high reproduction frequency band, the hill size of the honeycomb core causes vibrations, resulting in disturbance of frequency characteristics, increase in sound pressure distortion, and deterioration of sound quality performance.

This invention was made to solve the above-mentioned problems, and it improves the specific elastic modulus and internal loss of the entire diaphragm without impairing the characteristics of the honeycomb structure. The present invention provides a diaphragm that is highly functional and easy to handle.

[Means for solving problems]

The diaphragm according to the present invention is made of a honeycomb core material made of a magnetic composite vibration-proofing alloy (using a metal foil).

[For production]

The diaphragm of this invention uses a metal foil formed of a non-magnetic composite vibration-proof alloy for the honeycomb core material, thereby increasing the internal loss of the honeycomb core itself, and increasing the specific modulus of elasticity and internal loss of the entire diaphragm. Ll that improves [Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Third
In the figure, (1a) is a honeycomb core material formed from a non-magnetic composite anti-vibration alloy according to the present invention.

Skin 1 (21, (
31 to the adhesive (4).

The cause and mechanism of the damping ability of composite anti-vibration alloys is due to viscous flow (or plastic flow) at the interface between the outer phase and the second phase. The damping ability of the alloy is a mechanism based on a relaxation process based on the hesitation at the interface between the two phases of A/ and the β phase of Zn, and has the characteristic that it is almost independent of vibration stress.

Next, as an example, physical and mechanical properties will be shown in comparison with An.

As is clear from the above table, the internal wear value is 1 to 2 orders of magnitude higher than that of aluminum, which allows the internal loss of the entire diaphragm to be significantly improved compared to the conventional configuration, which is extremely good for a honeycomb core. . Specific modulus E/
ρ is also in no way inferior to aluminum, which has excellent properties as a core material, and considering its tensile strength, it can be made thinner than aluminum foil, so it can be made equally lightweight.

Further, in order to obtain the internal loss of the entire diaphragm, it is no longer necessary to perform a process to impart an internal loss to the skin material (resulting in a reduction in the specific modulus of elasticity of the skin material).

A particularly significant effect is the ability to reduce hill resonance that occurs at high reproduction frequencies. FIGS. 2 and 3 show characteristics according to an embodiment of the present invention, and it can be seen from the figures that the frequency characteristics and sound pressure distortion are improved.

〔Effect of the invention〕

As described above, according to the invention of B, the honeycomb core material is constituted by a foil made of a non-magnetic composite anti-vibration alloy.
It is possible to create a diaphragm with greater internal loss without sacrificing the light weight and high bending rigidity that are the characteristics of honeycomb diaphragms, and the degree of freedom in selecting the skin material increases. The advantage of being able to use a material with a high specific elastic modulus is that it is as inexpensive as the conventional method and has excellent workability.

[Brief explanation of drawings]

Figures 1 (a) and (b) are a cross-sectional front view and a cross-sectional side view of an embodiment of the present invention, Figure 2 is a diagram showing an example of the frequency characteristics of the conventional product and the present invention, and Figure 3 is a diagram showing an example of the frequency characteristics of the conventional product and the present invention. Diagrams showing an example of the sound pressure distortion characteristics of the same (conventional product and the present invention), Figure 4 (a) (b)
) and FIGS. 5(a) and 5(b) are a sectional front view and a sectional side view of a conventional example, respectively. (1): Honeycomb Jll structure, (Ia): Honeycomb core material, (21 (31: Cedar, wood). In the drawings, the same reference numerals indicate the same or equivalent parts.

Claims (2)

[Claims] (1) A diaphragm for an acoustic device that constitutes a honeycomb structure by applying skin materials to the front and back surfaces of a honeycomb core material, characterized in that the honeycomb core material is formed of a non-magnetic composite vibration-proofing alloy. A diaphragm for acoustic equipment. (2) The diaphragm for an acoustic device according to claim 1, wherein an Al-Zn alloy is used as the non-magnetic composite vibration-proofing alloy.