JPH0448072Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a dome diaphragm of a dome-shaped speaker.

As shown in FIG. 1, a dome-shaped speaker generally has a magnetic air gap formed between the center pole 12 and the front plate 13 of a magnetic circuit consisting of a magnet 11, a center pole 12, a front plate 13, and a back plate 14. Vibration plate 15
A voice coil 16 fixed to the outer periphery is inserted, and a sound current is passed through the voice coil 16 to drive the diaphragm 15 and emit sound waves.

The diaphragm 15 is usually made of cemented carbide metal such as duralumin, but this type of hard diaphragm has less mechanical internal loss in the diaphragm material at frequencies higher than the piston vibration range, so The transmitted vibration energy and the vibration energy reflected at the center of the diaphragm interfere with each other, resulting in so-called anti-resonance, which produces nodal lines near the outer periphery of the diaphragm. Since the vibration phases of the diaphragm are opposite to each other outside and inside this nodal line, a dip occurs in the frequency characteristics at the anti-resonance frequency (hereinafter referred to as Fh), and the A peak was generated in the frequency, the frequency characteristics and transient characteristics deteriorated, and the hearing was impaired.

Another configuration of dome-shaped speakers is the so-called soft dome speaker, which uses a soft material with extremely high internal loss for the diaphragm, but this type of diaphragm is less likely to cause resonance or anti-resonance, but the diaphragm has a large mass. , since vibration energy is difficult to transmit,
The drawback was that the conversion efficiency as a speaker was extremely low.

The diaphragm of the dome-shaped speaker invented in this application is a diaphragm that solves the drawbacks of the conventional diaphragm described above, and will be explained based on an example as shown in FIG.
In FIG. 3, a fiber group 11 made of high-rigidity fibers such as carbon fibers or polyimide fibers arranged in a plane so as to cover the entire surface of the diaphragm 3, and a fiber group 11 made of the same high-rigidity fibers. A group of fibers 12 arranged in a planar band shape, each of which overlaps at different angles, is aligned in the same direction, and has widths d2 and d3 each ranging from 5 to 45% of the total circumference of the dome diaphragm 3. , and 13 is impregnated with a synthetic resin 2 for both shaping and airtightness, and is then molded into a diaphragm. The widths d2 and d3 in which the fiber groups 12 and 13 are arranged are:
According to the experimental results, the sum is 10~ of the total circumference of the diaphragm 3.
Approximately 50% is appropriate.

In the diaphragm having the above configuration, if we pay attention to the fiber arrangement in the periphery of the diaphragm, we can see that there is an A1 part where only the fiber groups 11 are arranged in the meridian direction of the diaphragm, an A2 part where only the fiber groups 11 are arranged in the latitude direction, and fiber groups 11 and 12 are arranged in the diaphragm meridian direction. The B1 part where fiber group 11 and fiber group 13 are distributed coexist, and the stiffness of each part is different, so the stiffness of the diaphragm as a whole changes depending on the location. The state of change is diaphragm 3
The three-layer part at the center of is almost isotropic, but around this three-layer part are the two-layer structure B1 part,
The B2 part and the A1 part and A2 part of the one-layer structure coexist, and the rigidity changes along the circumferential direction, and the width of the B1 part, B2 part, A1 part, and A2 part is the entire circumference of the dome diaphragm 3. The pitch at which the rigidity changes is within the range of 5 to 40% of the length, and even if it exists continuously, without exceeding the range of 10 to 50% of the total circumference of the dome diaphragm 3 at one point. Since the dimensions are approximately on the same order as the wavelength of the primary resonance mode on the diaphragm at high resonance frequencies, there is no significant anti-resonance that causes nodal lines on the diaphragm at specific frequencies as mentioned above. The peaks and dips on the frequency characteristics are dispersed and disappear, and the frequency characteristics become flat.

Furthermore, for the same reason, the intersection angle of these plurality of fiber groups that intersect with the fiber group 11 and the width of the arrangement are also determined by the sum of the above-mentioned widths and the fiber group 11.
There are no limitations other than the state of the array.
However, the effect of preventing regular resonance of the diaphragm is greater when the intersection angle and width are irregular to some extent.

Fig. 4 shows the frequency characteristic 41 of a dome-type speaker using the dome diaphragm of the present invention. For comparison, as a conventional example, the frequency characteristic 42 of a dome-type speaker using a diaphragm obtained by overlapping two pieces of plain woven fabric of high-rigidity fibers with the weaves shifted by 45 degrees from each other, impregnating them with synthetic resin, and thermoforming them is shown. Comparing the two, the speaker using the dome diaphragm of the present invention has almost no peaks and dips in the 10KHz to 40KHz range, clearly demonstrating the effect of the dome diaphragm of the present invention.

As mentioned above, the diaphragm of the dome-shaped speaker of the present invention is a diaphragm formed by giving directionality and non-uniformity to the distribution of high-rigidity fibers constituting the diaphragm, and its rigidity varies depending on the location. By having a configuration that is different in terms of frequency, no significant nodal lines appear on the diaphragm even at Fh, and the frequency characteristics are not only flat, but also significant resonance and anti-resonance are dispersed and disappear. As a result, the transient characteristics also become better, so the auditory sensation becomes significantly better.

In addition, since the diaphragm is made of a hard material and is lighter than a soft dome diaphragm, there is no drop in efficiency and it is possible to obtain a dome-shaped speaker with excellent frequency characteristics not seen in conventional examples. It is.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a dome-shaped speaker, FIGS. 2 and 3 are illustrations of the fiber arrangement of the diaphragm of the dome-shaped speaker invented in this application, and partially enlarged sectional views;
FIG. 4 is a frequency characteristic diagram. 1 is a fiber aggregate, 11, 12, 13, . . . are fiber groups, 2 is a synthetic resin, and 3 is a diaphragm.

Claims (1)

[Scope of utility model registration request] A fiber group 11 in which high-rigidity fibers are arranged in one direction and arranged in a planar manner covering the entire surface of the dome diaphragm 3, and a fiber group 11 in which high-rigidity fibers are arranged in one direction and arranged in a planar manner covering the entire surface of the dome diaphragm 3 within a range of 5 to 45% of the total circumference of the dome diaphragm 3. It consists of two fiber groups 12 and 13 arranged in a plane with a width of
2 and 13 are the fiber group 1 at different angles, respectively.
1 and the two fiber groups 1
2 and 13 have a dome diaphragm 3 formed by impregnating and molding a synthetic resin 2 into a fiber aggregate 1 whose sum of arrangement widths d2 and d3 is 10 to 50% of the total circumference of the dome diaphragm 3. A dome-shaped speaker featuring