JPS5822372Y2 - Composite metal parts for acoustics - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an acoustic composite metal member, and more specifically, an acoustic composite metal member that achieves non-resonance and is suitable for speaker frames, cabinets, horns, diaphragms, reinforcing materials, etc. Regarding.

The following will explain based on the attached drawings.

The metal parts used in speaker cabinets etc.
As shown in the figure, conventionally, a metal part 1 with a vinyl chloride-based or butyl-based vibration damping material (thickness of about 5 mm) 2 pasted on the entire surface has been used.

However, the vibration isolation effect is only 5 to 10 dB at the vibration level.
In this case, there is a drawback that the propagation velocity and Young's modulus of the above vibration wave appear to decrease (see FIGS. 6 and 7).

The purpose of the present invention is to provide an acoustic composite metal member that achieves non-resonance by configuring two or more metal materials with different vibration wave propagation velocities to be bonded via a viscoelastic substance. .

FIG. 2 shows an embodiment of the present invention, and shows a structure in which metal plates A and B are bonded by interposing a viscoelastic material 4 such as double-sided adhesive tape between the bonding surfaces 3 and 3'.

In general, it is possible to eliminate resonance by joining two types of metals with different vibration wave propagation velocities, but in reality it is extremely difficult to join them in a mirror-like state due to warping of the metal plates.

Therefore, in the present invention, by interposing a viscoelastic material such as double-sided adhesive tape between the joint surfaces 3 and 3' of the metal plates A and B, the flatness of the joint surfaces 3 and 3' is poor. Even in this state, the bonding area can be increased.

In this case, an ideal non-resonant state occurs when the weights of the metal plates A and B are equal.

Another embodiment of the present invention is a metal plate A as shown in FIG.
, B are joined together via a viscoelastic body 4, and further joined and fixed with bolts.

The operation of the acoustic metal member according to the present invention configured as described above during vibration will be explained.

FIG. 4 shows the propagation characteristics of vibration waves in metal plates A and B, which have different vibration wave propagation velocities.

That is, when metal plates with different propagation speeds of vibration waves are joined together, as shown in the figure, since the vibration frequencies are different, a phase difference is generated, and the vibrations cancel each other out, resulting in a non-resonant state.

Therefore, as a matter of course, even if dissimilar metals are joined together, a non-resonant state will not occur if the propagation velocities are equal (for example, aluminum and iron).

Next, measurement data from experiments conducted to confirm the effects of the acoustic composite metal member according to the present invention will be explained.

First, a vibration test was conducted using a combination of three types of metal rods: aluminum, iron, and brass.

As shown in FIG. 5, the experimental method is as shown in FIG.
．． The sample 10 is suspended from the wall 11 by a support 12, one end of the sample 10 is struck by an impulse hammer 13, and a vibration wave is detected by a detector 14 fixed at the other end.

In this way, the transfer function of the vibration wave propagating through the sample rod is analyzed by a computer, and the analyzed frequency response characteristics are recorded by a recorder.

Here, the propagation speed of the metal rod is 5000 for aluminum.
(m/5ec), 5120 (m/5ec) for iron
, 3500 (m/5ee) for brass, and the sample used was an iron rod and a brass rod joined with double-sided tape.

The experimental results show that when they are bonded using a viscoelastic material (double-sided adhesive tape), a non-resonant state occurs because the propagation speeds of vibration waves in iron and brass are different (Figure 8).

Furthermore, the same effect can be obtained by joining non-magnetic metals such as aluminum and brass or stainless steel and brass, which have different propagation speeds of vibration waves, via a viscoelastic material.

As described above, according to the present invention, by joining dissimilar metals with different propagation velocities via a viscoelastic substance, it is possible to attenuate the vibration level of a single composite metal member to about 20 dB.

By the way, for metal parts with conventional vibration-proofing materials, the resistance is 5 to 10.
It is about dB.

Although the acoustic composite metal member according to the present invention has been described in the embodiment in which two types of metal materials are bonded together, the present invention is not limited thereto.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of a metal member used in a conventional audio equipment cabinet, etc.; FIGS. 2 and 3 are sectional views showing an embodiment of the acoustic composite metal member according to the present invention; Figure 4 is a diagram showing the propagation characteristics of vibration waves in dissimilar metals with different propagation velocities, Figure 5 is an explanatory diagram showing the experimental method for confirming the technical effects of the composite metal member according to the present invention, and Figures 6 to 6. FIG. 8 is a diagram showing measurement data.

Claims (1)

[Scope of utility model registration request] An acoustic composite metal member comprising two or more types of metal materials with different vibration wave propagation velocities bonded together via a viscoelastic substance.