JPS6034879B2 - Loudspeaker diaphragm manufacturing method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a loudspeaker diaphragm.

Conventionally, when manufacturing a diaphragm for a loudspeaker, it is desirable to have a large Young's modulus near the top of the vice principal's conical shape and a small Young's modulus near the periphery. The upper and lower mating gaps of the mold are gradually changed so that strong pressure is applied near the top of the mold, the pressure is gradually reduced as it approaches the periphery, and weaker pressure is applied near the periphery. A method of drying under pressure using a mold is considered, but with this method, if the mating gap is large at the periphery, the degree of heat transfer is not constant, so the top is dry, but the periphery is not yet sufficiently dry. In addition, if you try to sufficiently dry the surrounding area, there is a problem in that the top part is likely to be burnt. However, as a result of experiments, the Young's modulus of each part of the diaphragm obtained by this method was obtained as follows. Near the top
Near the periphery of 1.0×1 and starvation/
0.9×1 bi.

d skin e/uniformity Also, if the mating gap around the periphery of the mold is made small, the Young's modulus of such a diaphragm will be almost the same near the top and near the periphery, so when incorporated into a speaker, the bass will be lower. It becomes difficult to reproduce a wide range of sounds up to the high range than in a castle, and only a narrow range of sounds can be reproduced. The present invention dramatically extends the bass range and the treble range to obtain a wider range of reproduced sound, and also changes continuously from the bass range to the treble range to prevent distortion midway through. This is a method of manufacturing a diaphragm that was originally conceived. To explain this with respect to a practical example shown in the drawings, the vicinity of the top of the truncated cone-shaped diaphragm 3 is located between the upper mold la and the lower mold lb of the heating mold 1, as shown in FIG. and are evenly adhered to each other so that they can be compressed directly and dried.

{o} Part of the upper mold la is shaved off to form a lower mold so that the air gap 4 increases as shown in FIG. A gap 4 is provided between the material and the material lb to prevent immediate compression drying.

Along the periphery of the vice principal's yen-shaped diaphragm 3, 5,
A large number of holes 5' are made so that hot air 2, which is heated and compressed air, can be blown from the upper part of the upper mold la through the holes 5 and discharged from the lower part through the holes 5 of the lower mold lb. .

When manufacturing using the heating mold 1 as described above,
The diaphragm 3 in the shape of a battle cone in a water-containing state is sandwiched between the upper mold la and the lower mold lb of the heating mold 1, and an indirect material 6 such as a sashimi, felt, or blanket is placed between the upper mold la and the lower mold lb of the heating mold 1. is placed over the diaphragm 3 as shown in Fig. 1, and is strongly pressed with the heating mold 1. At the same time, hot air 2 for heating and compression is sent from the upper part of the upper mold la through the holes 5, and the hot air 2 compresses and dries it. do. In this case, strong pressure is applied to the top of the headmaster's bell-shaped diaphragm, and the gap 4 is designed to gradually become larger from near the top to the periphery. 2, the pressure is applied gradually to become weaker, with the weakest pressure being applied to the periphery. The diaphragm obtained by the above method has a large Young's modulus near the top of the vice principal's conical shape, and decreases from near the top to the periphery, and the Young's modulus is the highest at the periphery. is getting smaller,
A diaphragm 3 is obtained.

As an example of a diaphragm obtained by the above manufacturing method, a Young's modulus having the following numerical value was obtained. Near the top
Near the periphery of 1.1×1biod skin e/
The change in Young's modulus from the vicinity of the top of the diaphragm 3 of 0.5×1 to the periphery is due to the change in the capacitance of the air gap 4 and the indirect material 6.
Due to the cushioning effect, the change in compression ratio is gradual, there are no discontinuous points, and bending of the diaphragm and abnormal vibration are extremely rare.

In the diaphragm obtained by the present invention, the vicinity of the top of the truncated cone-shaped diaphragm is densely stretched in the heating mold 1 in a hydrous state, so the paper fibers are tightly tightened and the Young's modulus is large. Therefore, when it is incorporated into a loudspeaker, the high frequency reproduction limit h becomes higher and the sound pressure in the high frequency range improves.Also, near the periphery, the water content of the paper fibers will evaporate while the paper fibers remain finely cut. , the Young's modulus is significantly higher than 4. Therefore, when incorporated into a loudspeaker,
The lowest resonant frequency has been lowered, and the reproduction of bass frequencies has been significantly improved.By gradually changing the compression ratio of hot air 2 from near the top to the periphery, changes in each frequency band from treble to bass. Accordingly, this is a manufacturing method for obtaining a diaphragm in which the Young's modulus is gradually changed.

The present invention skillfully combines the methods of compression drying and molding using a heated mold and compression drying and molding using heated compressed air, and the Young's modulus of the diaphragm obtained by both methods. This is a method of manufacturing a diaphragm for a loudspeaker that produces a remarkable effect by piecing together gradual changes without sudden changes.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the heating mold 1. 1 is a heating mold, la is an upper mold, lb is a lower mold, 2 is hot air, 3 is a diaphragm, 4 is a gap, 5 and 5' are holes, and 6 is an indirect object.

Claims (1)

[Claims] 1 Pressure is applied with heating mold 1 from the top of the truncated conical shape to the periphery, and the Young's modulus of the diaphragm is gradually changed locally by applying pressure with hot air 2 and drying. In order to achieve this, a loudspeaker diaphragm manufacturing method that continuously changes the capacity of a void 4 provided in a mold and also uses a cushion material 6 such as felt or blanket.