JPH0746689A - Speaker diaphragm and manufacture therefor - Google Patents

Abstract

PURPOSE:To obtain a speaker diaphragm which is capable of suppressing deflection displacement at the time of resonance without increasing the manufacture process of a speaker diaphragm. CONSTITUTION:A diaphragm 1 has a conical shape where inclination (theta) is 34 deg. and aperture diameter is 12cm and is provided with a thickness part in an annular form at a radius location where the outside diameter ratio of the diaphragm 1 becomes 0.67 (tantheta) as a center. Therefore, because the deflection displacement at the time of resonance can be suppressed as a specified portion where the deflection displacement is generated at the time of resonance becomes thick and this deflection displacement is inversely proportional to Young's modulus and the cube of the thickness, the generation of a remarkable peak or dip in the frequency characteristic of a speaker can be suppressed and a flat pressure frequency characteristic can be obtained without lowering the output level of the speaker.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker diaphragm and a method of manufacturing the diaphragm.

[0002]

2. Description of the Related Art Generally, a paper diaphragm is the most popular speaker diaphragm, and a method for manufacturing the paper diaphragm is to produce wood pulp fibers dispersed in water by a cone-shaped paper net. In some cases, a conical speaker diaphragm is manufactured by drying wood pulp fibers accumulated on the surface of the paper making net. In the speaker diaphragm manufactured in this manner, the amount of water per unit area passing through the conical papermaking net is substantially uniform, so that the thickness of each part of the speaker diaphragm is uniform.

By the way, the frequency characteristic of the speaker diaphragm is determined by the shape and physical properties of the diaphragm, and the speaker diaphragm resonates at a specific frequency to cause a large flexural displacement at a specific portion of the diaphragm. Appears as peaks and dips above. The amount of flexural displacement generated at this specific frequency is inversely proportional to the Young's modulus of the diaphragm material and the cube of the thickness. Therefore, in the conventional paper-made vibrating plate made of wood pulp fiber, after forming the vibrating plate, the corrugation is pressure-formed by using a mold or the like to increase the Young's modulus to suppress the flexural displacement at the time of resonance.

[0004]

However, in order to provide the corrugations as described above, it is necessary to form the vibrating plate and then press it with a mold or the like to increase the number of manufacturing steps. However, it is difficult to change the thickness of each part of the diaphragm by press forming with a mold, etc.In order to suppress the flexural displacement at resonance by increasing the thickness of the diaphragm, it is necessary to increase the thickness of the entire diaphragm. Not
As a result, there is a problem that the weight of the diaphragm is increased and the output level of the speaker is lowered.

An object of the present invention is to provide a speaker diaphragm capable of suppressing flexural displacement at the time of resonance without increasing the number of manufacturing steps.

[0006]

SUMMARY OF THE INVENTION The present invention is to solve the above problems. According to the present invention, a speaker diaphragm having a conical shape is provided with an annular thick portion, and the thick wall portion is provided. The diameter of the part is set based on the ratio of the tangent of the inclination angle of the cone to the outer diameter of the diaphragm.

According to the second aspect of the present invention, a conical paper net is arranged in the water passage to fabricate fibers dispersed in water, and the fibers are allowed to accumulate on the surface of the paper net. In the method of manufacturing a speaker diaphragm for drying a conical speaker diaphragm by drying the fibers, the water passage located on the back side of the papermaking net is a first water passage having a large water passage amount per unit area. And a second water passage having a smaller amount of water per unit area than the first water passage, so that more fibers are accumulated on the paper making net facing the first water passage than other portions. It is the one.

[0008]

Therefore, according to the first aspect of the invention, the diameter of the thick portion is set based on the ratio of the tangent of the inclination angle of the cone to the outer diameter of the diaphragm, and the position of the diameter is set. By providing a ring-shaped thick portion at the specific frequency of the diaphragm where resonance occurs at a specific frequency is thicker than other parts, the flexural displacement at resonance is inversely proportional to the cube of the thickness. It is possible to suppress the deflection displacement at the time, and also
By increasing the thickness of only a specific portion of the diaphragm where resonance occurs, the weight increase of the diaphragm can be minimized.

According to the second aspect of the present invention, a conical papermaking net is arranged in the water passage, and the water passage located on the back side of the paper making per unit area is The first water passage with a large amount of water and the second water passage with a smaller amount of water per unit area than the first water passage are formed into compartments, and the fibers dispersed in the water are machined to face the first water passage. Resonance occurs as described above by accumulating more fibers than other parts on the paper making net and drying the piled fibers on the paper making to manufacture the speaker diaphragm. It is possible to manufacture a speaker diaphragm in which only the diaphragm portion is thickened.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic sectional view of a speaker diaphragm according to an embodiment of the present invention, and FIG. 2 is an explanatory view showing a paper making process of the speaker diaphragm. FIG. 3 is a side sectional view showing an outline of a speaker using the same speaker diaphragm, and FIG. 4 is a frequency characteristic diagram of a speaker using the same speaker diaphragm.

In FIG. 1, the diaphragm 1 has a conical shape with an inclination angle (θ) of 34 ° and a diameter of 12 cm, and is centered on a radial position where the outer diameter ratio of the diaphragm is 0.67 (tan θ). The thick portion 1a is provided as a ring.

A method of manufacturing the diaphragm 1 will be described with reference to FIG. In FIG. 2, reference numeral 11 is a water passage in which a conical papermaking net 12 is arranged, and the back side of the papermaking net 12 is divided into a zone A, a zone B and a zone C by a partition frame 13. ing.

Reference numeral 14 is a drainage port for adjusting the amount of water flow through each region defined by the partition frame 13. By adjusting the size of the drainage port 14, the amount of water flow per unit area of area A and area C is adjusted. And the amount of water flow per unit area in the area B is made larger than the amount of water flow per unit area in the areas A and C. The area B divided by the partition frame 13 is the first water passage, and the areas A and C divided by the partition frame 13 are the second water passages.

With the above structure, the amount of water passing through the back side of the paper making net 12 is different between the areas A and C and the area B, and accordingly, the amount of water passing through the paper making net 12 is also in the area A. , C and area B are different. Therefore, the fibers evenly distributed in the water passing through the water passage 11 have different amounts of water passing through the paper making net 12 between the areas A and C and the area B, so that the surface of the paper making net 12 is The thickness of the stagnant fibers 15 accumulated above is different. In other words, area B with a large amount of water passing through
Fibers 1 accumulated on the surface of the paper making net 12 facing the
5 is thicker than the accumulated fibers 15 accumulated on the surface of the paper making net 12 facing the areas A and C where the amount of water passing through is small.

Therefore, the vibrating plate 1 produced by drying the accumulated stagnant fibers 15 has the area B in the area A,
The area is thicker than the area C, and the area B is the thick portion 1a.

A general speaker using the speaker diaphragm manufactured as described above will be described with reference to FIG.

As shown in FIG. 3, the speaker generally comprises a magnetic circuit portion 21 and a vibrating portion 22, of which the magnetic circuit portion 21 includes a circular flat plate portion 23a and the flat plate portion 2.
A cylindrical center pole 23b provided at the center of 3a
And a ring-shaped magnet 24 fixed to the center pole 23b of the flat plate portion 23a concentrically with the center pole 23b, and the magnet 24.
On the upper end surface of the magnet, a magnet 24 and an annular upper plate 26 provided concentrically are formed. The air gap formed between the magnet 24 and the upper plate 26 and the center pole 23b is used as a magnetic gap to guide the magnetic flux from the magnet 24 to the voice coil 25 described later.

The vibrating portion 22 is a cone.
The diaphragm 1 is provided with a ring-shaped thick portion 1a, and a voice coil bobbin 25a of a voice coil 25 as a vibration source is bonded to a central hole portion which is the top of the cone. It is fixed by etc. A flexible annular damper 30 is fixed to the voice coil 25 and the diaphragm 1 by adhesion or the like, and the outer peripheral portion of the damper 30 is fixed to the upper end surface of the upper plate 26 in a conical shape. The frame 27 is elastically supported by adhesion or the like. On the other hand, an edge 28 is adhered to the outer periphery of the cone bottom of the diaphragm 1, and the edge 28 is fixed to the edge support portion 27a of the frame 27 by adhesion or the like. That is, the frame 27 supports the diaphragm 1 by the edge 28 and the damper 30. Further, a dust cap 29 for preventing dust is provided on the voice coil 25 side of the diaphragm 1.

The solid line A of FIG. 4 shows the frequency characteristics of a 12 cm oral speaker using the diaphragm 1 shown in FIG. The broken line B in FIG. 4 indicates the frequency characteristics of a comparative example using a speaker prototyped using a paper speaker diaphragm in which the thickness of each part of the diaphragm is uniform.

Here, it can be seen that, in the frequency characteristic shown by the broken line B in FIG. 4, the sound pressure peak due to the natural resonance of the diaphragm and the dip due to the reverse resonance occur at around 7 kHz and 9 kHz. On the other hand, in the frequency characteristics of the speaker using the diaphragm according to the example, such peaks and dips are not recognized. That is, in the diaphragm 1 formed in a conical shape, the thick portion 1a is provided annularly around the radial position where the outer diameter ratio of the diaphragm 1 becomes tan θ when the inclination angle of the diaphragm 1 is θ. Makes thicker the specific part where flexural displacement occurs at resonance,
Since this flexural displacement is inversely proportional to the Young's modulus and the cube of the thickness, the flexural displacement at resonance can be suppressed,
It is possible to suppress the occurrence of a remarkable peak or dip in the frequency characteristic of the speaker.

Therefore, as described above, the diaphragm 1 having the thick portion 1a provided annularly around the radial position where the outer diameter ratio of the diaphragm 1 is tan θ when the inclination angle of the diaphragm 1 is θ. The speaker used has excellent frequency characteristics and excellent acoustic characteristics.

In this embodiment, the drainage port 1 is used as a means for adjusting the amount of water passing through the back side of the paper making net 12 in the method of manufacturing the diaphragm 1.
The size of No. 4 was adjusted, but the size is not limited to this. For example, between the paper making net 12 and the partition frame 13 (a, b in FIG. 2).
It is also possible to adjust the water flow rate on the back side of the paper making net 12 by providing a gap and adjusting the gap.

[0023]

As described above, according to the first aspect of the invention, in the conical diaphragm, the ratio of the tangent of the inclination angle of the cone to the outer diameter of the diaphragm is based on the ratio. By setting the diameter of the thick part and providing an annular thick part where the diameter is located, resonance occurs at a specific frequency and the specific part where flexural displacement occurs becomes thicker than other parts. Since the flexural displacement at the time is inversely proportional to the Young's modulus and the cube of the thickness, the flexural displacement at the time of resonance can be suppressed, so that it is possible to suppress the occurrence of a remarkable peak or dip in the frequency characteristic of the speaker. By increasing the thickness of only the specific part of the diaphragm where resonance occurs, the increase in the weight of the diaphragm can be minimized. Therefore, the flat sound pressure frequency can be maintained without lowering the speaker output level. It is possible to obtain several properties.

According to the second aspect of the invention, a conical papermaking net is arranged in the water passage, and the water passage located on the back side of the paper making net is connected to the water passage per unit area. Paper is divided into a first water passage having a large amount of water and a second water passage having a smaller amount of water per unit area than the first water passage, and the fibers dispersed in the water are made into paper and facing the first water passage. By accumulating more fibers on the mesh than other parts and drying the accumulated fibers on the paper mesh to manufacture a speaker diaphragm, it is possible to increase the number of working steps without increasing the work process. Only the thicker can be formed.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a speaker diaphragm according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing a paper making process of the speaker diaphragm.

FIG. 3 is a side sectional view showing an outline of a speaker using the speaker diaphragm.

FIG. 4 is a frequency characteristic diagram of a speaker using the speaker diaphragm.

[Explanation of symbols]

 1 Diaphragm 1a Thick part 11 Water passage 12 Paper making machine 13 Partition frame 14 Drainage port 15 Accumulated fiber

Claims (2)

[Claims] 1. A speaker diaphragm having a conical shape,
A speaker diaphragm, wherein an annular thick portion is provided, and the diameter of the thick portion is set based on a ratio of the outer diameter of the diaphragm to the tangent of the inclination angle of the cone. 2. A conical paper net is placed in a water passage to fabricate fibers dispersed in water, and the fibers accumulated on the surface of the fabric are dried. In the speaker diaphragm manufacturing method for manufacturing a conical speaker diaphragm, a water passage located on the back side of the papermaking net is provided with a first water passage having a large water passage amount per unit area and the first passage. It is characterized in that it is divided into a second water passage having a smaller amount of water per unit area than the water passage, and that more fibers are accumulated on the paper making net facing the first water passage than in other portions. Manufacturing method of speaker diaphragm.