JPS60228643A - Diaphragm for electroacoustic transducer - Google Patents

Abstract

PURPOSE:To obtain the titled inexpensive and safe diaphragm having a high Young's modulus, low density and high performance by adding a specified amount of Li to Al and melting and alloying them by heating. CONSTITUTION:An Al-Li alloy diaphragm for an electroacoustic transducer having a high Young's modulus and low density is obtd. by adding 10-30wt% Li to Al and melting and alloying them by heating. The diaphragm has an increased modulus of specific elasticity and physical characteristics most suitable for a diaphragm. It is inexpensive and harmless to the human body and can be provided with high performance without using Be or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a diaphragm for an electroacoustic transducer made of an AA'-Li alloy whose physical properties such as Young's modulus are optimal for a diaphragm for an electroacoustic transducer.

[Technical background of the invention and its problems]

Diaphragm materials for acoustic transducers are required to have a wide reproduction band, flat frequency characteristics, and low harmonic distortion, phase distortion, and the like. In particular, the width of the reproduction band is greatly influenced by the material and organizational structure of the diaphragm itself.

Conventionally, paper A7! has been used as a diaphragm material for acoustic transducers. ,
Ti is used.

In general, diaphragms made of metal materials have low internal loss, produce significant resonance in the high frequency range, and exhibit high peak frequency characteristics, with phase distortion and harmonic distortion occurring near the resonance frequency. Therefore, using a metal material as a diaphragm can be solved by using a material with a large Young's modulus E and moving the high-frequency resonance region to a frequency that does not affect the used band, but All and Ti are Because the elastic modulus is not large,
The high-frequency resonance point could not be made high, and only acoustic transducers with a narrow reproduction band could be manufactured.

This uji A7! Among the diaphragm materials of the A7!
There were those whose surfaces were treated with alumite, and alloys such as duralumin, but both had a Young's modulus of E of about 30% at most.
This was the limit on which it could be increased, and it was not yet sufficient.

The physical properties of AR or AR surface treated with alumite, duralumin, Ti density ρ, Young's modulus E, specific elastic modulus E/ρ are AR, or AR surface treated with alumite, duralumin, Ti Table 1 is obtained by comparing the metals.

From Table I above, as an aluminum-based diaphragm material /l
The specific elastic modulus E/
ρ is A7! Since the increase is only about 20% compared to that of , it cannot be said to be a suitable diaphragm material.

By the way, A! ! When we show the effect of added elements on the density ρ of the alloy and the effect of added elements on the Young's modulus E of the 1,1 alloy, we obtain graphs S and R as shown in Figures 1 and 2, respectively. . From these graphs S and R, it can be seen that increasing the Young's modulus E increases the density ρ, while decreasing the density ρ increases the specific elastic modulus E/ρ in order to decrease the Young's modulus E. It is an effective additive element.

However, since Be is harmful to the human body, has low solid solubility, and is expensive, Li is most suitable for obtaining a cheap, safe, and high-performance diaphragm for an acoustic transducer.

[Purpose of the invention]

This invention was made in view of the above points, and its purpose is to reduce the density ρ of AA and increase the Young's modulus E, that is, to increase the specific elastic modulus E/ρ. A7 with the most suitable characteristics as a diaphragm! -Li
The object of the present invention is to provide a diaphragm for an electroacoustic transducer made of an alloy based on the electroacoustic transducer.

[Embodiments of the invention]

An embodiment of the present invention will be described below.

Density 0.534 (g/aJ) in Al with purity 99.9%
The Al1-Lt gold alloy obtained by adding about 3w% of L+ and heating and melting at a temperature of about 750°C has a physical property of density ρ of 2.0 (g/c+1) and Young's modulus E of 1.
0000 (kg/w2), specific elastic modulus E/ρ is 5.0
(X109c+n).

Furthermore, when adding Li to AN under the same conditions as in the above example, the amount of addition is 5wt%, 10-1%, 20wt%,
Addition amount of Li and Young's modulus E when increasing to 30-t%
(kg/mm2) is the graph P shown in Figure 3, and the increase in the amount of Li added and the density ρ (g/mm2) are shown in graph P shown in Figure 3.
cJ), Young's modulus E (kg/sa") - specific modulus E/
The relationship between ρ(X 109am) and physical properties is shown in Table 2 below.

From the above table ■ and the graph P shown in Figure 3, it is clear that Al and Li
When 5 wt% of is added, the specific elastic modulus E/ρ is 1.
When 10 wt% of Li is added, it becomes 2.0 times that of An, and when 30 wt% Li is added, it becomes about 5 times that of /l, improving the specific elastic modulus E/ρ. I understand that. It is also seen that the density ρ decreases as the amount of Li added to Al increases. Like this A
As the amount of Li added to l increases in the range of 3 to 30 wt%, the Young's modulus E increases and the density ρ decreases, so the manufactured Alt-1-i alloy has a large specific elasticity. The ratio is E/ρ.

In the above example, the amount of Li added to A1 was 10
Although the explanation is based on the case where ~30 wt% is added, Aj! -10 to 30 wt of Li in the entire Li alloy
By adding small amounts of other elements Mn and Zr so that the composition becomes can. More Aj! Oxidation may be prevented by forming a non-oxidizing thin film on the surface of the acoustic transducer diaphragm made of -Li alloy by means of vapor deposition or the like.

〔Effect of the invention〕

As mentioned above, in the present invention, 10 to 30 wt% of Li is added to Al.
By adding within the range of A7! Since the density ρ can be lowered and the Young's modulus E can be increased, the specific elastic modulus E/ρ can be compared to the conventional AIAβ
It is larger than those treated with alumite (A1203) or electroacoustic diaphragms made of metal or alloy materials such as duralumin or Ti, and is suitable as a diaphragm material. Aj again! -It is cheaper and has better workability than Be alloy.

[Brief explanation of drawings]

Figure 1 is a characteristic diagram showing the effect on the density ρ when various elements are added to 8β, and Figure 2 is the same Young's modulus E.
Figure 3 is a characteristic diagram showing the influence of L on AJ.
It is a characteristic diagram showing the relationship with Young's modulus E when i is added.

Claims (1)

[Claims] A diaphragm for an electroacoustic transducer made of an A1-Li alloy obtained by adding 10 to 30-t% of ■-i to Ap and then heating and melting it to form an alloy.