JPH01256899A - Diaphragm for acoustic device - Google Patents

Abstract

PURPOSE:To obtain a diaphragm which has a larger internal loss without increasing the weight neither damaging the high elasticity by making the diaphragm of a vibration damping aluminium alloy. CONSTITUTION:A diaphragm 1 is made of a vibration damping aluminium alloy. With respect to an Al-Si based alloy to be used, Si particles are deposited in Al being a matrix and form eutectic crystal when Si is added into Al. The boundary surface of Si particles in a second phase absorbs the vibration to improve attenuation capability Q<-1>. Thus, the internal loss of the whole of the diaphragm is considerably improved in comparison with a conventional constitution and the obtained diaphragm is satisfactory as the diaphragm for acoustic devices.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a diaphragm for an acoustic device.

[Conventional technology]

In general, diaphragms for audio equipment have a structure in which a single plate, multiple plates are bonded together, or a structure in which the diaphragm is bonded to the outermost layer on the front and back of a core material filled with a two-cam structure or foamed resin. There is something. The diaphragm of these boards is conventionally made of paper made of natural or synthetic fibers.

It was composed of mixed paper or resin film and metal plates such as aluminum. 1 Next, this diaphragm will be explained. in general.

The diaphragm for audio equipment (hereinafter referred to as diaphragm 1) is:

It is required that the specific elastic modulus is 2, bending rigidity and internal loss are large. Here, the specific elastic modulus is /ρ (E is Young's modulus, ρ
The larger the density), the higher the limit resonance frequency and the wider the reproduction frequency band. Also, the larger the bending rigidity E (I is the moment of inertia of area), the more the distortion is reduced, and the larger the internal loss.

The sharpness Q value of mechanical resonance is reduced and the characteristics are flattened.
A diaphragm with good acoustic properties can be obtained. Various materials for the diaphragm have been adopted from a similar standpoint. However, since these properties have elements that conflict with each other, it has been extremely difficult to satisfy all of these properties using a single existing material. In order to solve these problems, a diaphragm made by a composite lamination method using two or more different materials is devised to achieve both high elasticity, high rigidity, and high internal loss by separating mutually contradictory elements. However, this method was not completely satisfactory from an industrial point of view, as the specific elastic modulus was lowered, productivity was poor, and costs were high.

[Problem to be solved by the invention]

Conventional diaphragms are constructed with a coefficient of 1 or more, so a diaphragm with a large specific elastic modulus of 11C/ρ has a very small internal loss, and a metal plate such as aluminum, which has a particularly excellent elastic modulus, has a low internal loss. Since the frequency characteristics were small, a peak dip occurred in the frequency characteristics, and good characteristics could not be obtained. In addition, when using a single paper and polymer diaphragm bonded together to increase internal loss, the specific elastic modulus E/ρ is low,
There was a problem that the limit resonance frequency became low.

This invention was made in view of the above-mentioned nine problems, and aims to improve the specific elastic modulus and internal loss of the entire diaphragm, and to obtain an excellent diaphragm that has the same workability and handling properties as conventional diaphragms. shall be.

[Friendly means of solving problems]

The diaphragm according to the present invention uses a vibration-proof aluminum alloy as its material and has the following properties. .

[Effect]

The diaphragm according to the present invention is made of a vibration-proof aluminum alloy, thereby increasing the total internal loss of the diaphragm and improving the specific elastic modulus and internal loss of the entire diaphragm.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 shows the first embodiment, which consists of a single diaphragm (1).

This perturbation plate is made of a vibration-proof aluminum alloy. The second prisoner is the second embodiment, with multiple boards (1a) (1b)
This is a laminated nine-diaphragm diaphragm, with at least one surface made of vibration-proof aluminum alloy.

Figure 3 shows the second embodiment, in which a core material (1) filled with a honeycomb structure or foamed resin, and a diaphragm (1) bonded to the front and back surfaces (
At least one surface of 1a) and 1b is made of a vibration-proof aluminum alloy.

Four examples of anti-vibration aluminum alloys used for the diaphragm in this invention are shown below.

Examples 1 and 2 are Al-81 alloys, Examples 3 and 4
is an Al-Ni alloy.

Note that the components in each of these Examples are expressed in weight percentages.

(Example 1) (Example 2) (Example 3) (Example 4) 8110% 8110% N16% N1
6%FeO, 05%FeO, 05% 760.
05% F'60.05% Zr O, 0596Zr
105% Zr O, 05% Zr 0.05%M
MO, 1% MM O, 1chi MM 0.1%
MMO, 1% NaO, 002% an O, 08%
kl'IA9 anα08chi Al remaining AI
! Remaining A11ARepeat l'' MM J in each of the above examples is Mitsushi metal, and its composition is 'La35%, 0.43%, 1.J41S%,
Pr: 4%, Sm: 1%, Y and others: 2%.

The causes and mechanisms of the damping ability of anti-vibration aluminum alloys are as follows:
It is thought that vibrational energy is absorbed by viscous flow at IJ lux boundaries, grain boundaries, and cell grain boundaries, and micro defects in crystals such as dislocations, vacancies, and stacking faults.

The damping capacity Q-1 indicates the length fft of converting externally applied vibration energy into thermal energy.

It is expressed as

The Al-8j alloy used in Examples (1) and (2) of the present invention is as follows.

When 81t- is added to Al, the matrix Al
81 particles precipitate inside, forming a eutectic crystal. And the second phase, 81, the particle interface absorbs vibrations and has a damping capacity Q
lt-improvement.

? θ, zr*VeT1 and rare earth elements have the function of making the crystal finer and increasing grain boundaries, and IJa and sr have the function of making the crystal finer and increasing the grain boundaries.

81 It works to make particles finer. Moreover, the above-mentioned Example 2
When Ken is included, it precipitates finely at the grain boundaries, increases the viscosity of one grain boundary, and improves the damping ability.

The embodiments of the present invention (favorable ranges tMf1 percentage of each component in IH21) are as shown in Table 1 below, and even if it is more or less than that, the following problems will occur.

In addition, in the Al-81 alloy according to the second embodiment of the present invention (11 (21), second phase particles (s1
It is preferable that the average particle diameter of the particles is 10 μm or less, and by setting it to 10 μm or less, the interface of the second phase particles can be increased and a large damping ability can be obtained.

Furthermore, the average particle diameter is more preferably 7 μm or less, and even more preferably 5 μm or less.

In addition, when the Al-H1 alloy of Example 31 (41) of the present invention is added to Al Ic Ni', Ni particles precipitate in the matrix AJ, forming a eutectic structure.

Then, the interface of Al3Ni particles, which is the second phase, absorbs,
Damping ability Q't-Improve.

Furthermore, 'e*Zr, V, TI, and rare earth elements refine the crystals, increase grain boundaries, and improve the damping ability Q1 f.

Further, when K e 8 n f is contained as in Example (4), it precipitates finely at grain boundaries, increasing the viscosity of one grain boundary, and improving the damping capacity Q1.

Preferred ranges I21tl (weight percentages) of each component in Example T31 (41) of the present invention are as shown in Table 2 below, and even if they are more or less than that, the following problems will occur.

In addition, in the Al-N1 alloy according to the embodiment of the present invention (31+41), the crystal structure has a second phase (AI3N1
It is preferable that the particle size of the particles is 10 μm or less, and by setting it to 10 μm or less, the interface of the second phase particles can be increased and a large attenuation ability can be obtained.

Note that the average particle diameter is more preferably 1 μm or less, and even more preferably 9, which is 5 μm or less.

Next, the Al-Ni alloy of the example of the present invention, Al-81
Table 3 below shows a comparison between the alloys, Al (ADC-12), and Zn--Al alloy (trade name: Cosmar 2).

As is clear from the table above, the attenuation capacity Q1 of the present invention OA
Both l-Ni alloy and Al-81 alloy.

It is more than one order of magnitude larger than Al (ADO-12). As a result, the internal loss of the entire diaphragm can be significantly increased compared to the conventional structure, making it extremely suitable as a diaphragm for acoustic equipment. In addition, the specific elastic modulus is not comparable to that of aluminum, which has excellent properties, and Al-60%Zn
(:ffsmar-kZ)yoF), the specific elastic modulus E/ρ is excellent, and weight reduction can be achieved.

Furthermore, although it has good damping ability, in order to obtain the internal loss of the entire diaphragm, the conventional process of bonding multiple materials together to reduce internal loss (as a result, the diaphragm The specific elastic modulus of
This provides a high degree of freedom in design. Figures 4 and 5 show the characteristics of the above-mentioned embodiment, where the solid line shows the conventional product and the wavy line shows the embodiment, showing that the frequency characteristics and sound pressure distortion have been improved. Recognize. Further, in the above embodiment, a diaphragm for an audio device was described.

A dust camp may also be used, and the same effect as in the above embodiment can be achieved.

〔Effect of the invention〕

As described above, according to the present invention, since the diaphragm is made of anti-camera aluminum alloy, it is possible to obtain a diaphragm with a large internal loss without sacrificing its lightweight and high elasticity, and at an inexpensive price. This has the effect of improving workability.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view showing one embodiment of the present invention. Second. FIG. 3 is a cross-sectional side view showing another embodiment of the present invention, FIG. 4 is a diagram showing an example of frequency characteristics according to the conventional product and the present invention, and FIG. 5 is the same (sound pressure distortion according to the conventional product and the present invention). This is a diagram showing an example of the characteristics (1) #Lla), Ll'
)...Diaphragm In the figures, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] (1) In a diaphragm for an audio device composed of a single plate or multiple layers, a vibration-proof aluminum alloy is used as the material of at least one outermost layer of the diaphragm of the single plate or multiple layers. Characteristic diaphragm for acoustic equipment. (2) A patent characterized in that the anti-vibration aluminum alloy is either an Al-Ni alloy containing 4 to 10% by weight of Ni or an Al-Si alloy containing 8 to 20% by weight of Si. A diaphragm for an acoustic device according to claim 1.