JP3384098B2 - Method of manufacturing diaphragm for speaker - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a diaphragm for a speaker using a resin film, which is a main part of a speaker used in various audio equipment.

[0002]

2. Description of the Related Art Conventionally, a speaker diaphragm of this type has been formed by heating and pressing a resin film in advance to a softening point of the film or higher and pressing the film into a desired shape using a molding die. It was obtained by molding.

FIG. 8 shows a molding die for manufacturing such a conventional diaphragm for a speaker, which comprises an upper die 21 shown in FIG. 8A and a lower die 22 shown in FIG. The upper die 21 and the lower die 22 each have a surface integrated with a portion for molding the diaphragm main body and a portion for molding an edge portion having a corrugated cross section on the outer peripheral portion. ing.

Further, FIG. 9 shows a conventional speaker diaphragm manufactured by the molding die described above, in which an edge portion is integrally formed on the outer peripheral portion of the diaphragm main body.

[0005]

However, in the speaker diaphragm obtained by the above conventional manufacturing method, the relationship between the thickness of the edge portion of the diaphragm and the thickness of the edge portion of the diaphragm is almost the same. It tends to be slightly thicker than the thickness of the diaphragm main body, and if the material thickness of the edge part of the speaker diaphragm is about the same as the thickness of the diaphragm main body, or if it is slightly thicker, Stiffness is large, the balance is poor compared to the rigidity of the diaphragm main body, not only split resonance of the diaphragm main body is likely to occur but also the reduced reproduction is insufficient, and the peak on the output sound pressure reproduction frequency characteristic, The problem is that dips are likely to occur.

In recent years, there has been an increasing demand for speaker diaphragms using particularly high-rigidity resin films, and it is desired to have characteristics of high sound quality and a wide reproduction frequency band. If this requirement increases, the problem will become more serious. It was

The present invention solves such conventional problems,
Manufacture of speaker diaphragm that can provide stable and inexpensive speaker diaphragm with excellent performance
It is intended to provide a method .

[0008]

In order to solve the above-mentioned problems, a method of manufacturing a diaphragm for a speaker according to the present invention comprises an edge portion on the periphery of a diaphragm body, and the thickness of the edge portion is the thickness of the diaphragm body. To make it thinner than the thickness of
As a method for manufacturing a vibration plate for a mosquito, when a resin film used as a material for the vibration plate is heated to a softening point or higher to be formed,
The resin film is formed such that the elongation rate of the resin film is large at the edge portion and small at the diaphragm main body portion.

[0009]

With this configuration, it is possible to reduce the resonance frequency of the speaker by reducing the stiffness of the edge of the speaker diaphragm using the resin film having high rigidity, and the diaphragm main body is also well balanced and the divided resonance of the vibration surface. It is possible to obtain a diaphragm for a speaker, which has a low frequency, a high sound quality, and a wide frequency band.

[0010]

EXAMPLES First, a method for manufacturing a speaker diaphragm of the present invention
Before describing the examples of
Speaker diaphragm and speakers using this speaker diaphragm.
The marker will be described with reference to the drawings.

FIG. 1 is a half sectional view showing the structure of a speaker diaphragm obtained by the present invention . This diaphragm 1 is formed by processing a polyethylene naphthalate film having a substrate thickness of 50 μ, An edge portion having a corrugated cross section is integrally formed on the outer periphery of the diaphragm body.

In this diaphragm 1, the thickness t1 of the diaphragm main body is 48 μ and the thickness t2 of the edge portion is 35 μ, and the thickness t2 of the edge portion is smaller than the thickness t1 of the diaphragm main body portion. It is thinly formed, and its ratio is about 73%.

[0013] Figure 2 is shows the structure of a small speaker which is called a micro loudspeaker using the diaphragm 1 for the speaker in half cross-sectional view, 1 in 2 diaphragm 2
Is a voice coil coupled to the center of the diaphragm 1, and 3 is a magnetic circuit having a magnetic gap 7 into which the voice coil 2 fits. The magnetic circuit 3 includes a pot type yoke 4, a magnet 5 and a plate 6. It is configured to be laminated and joined. Further, 8 is a frame coupled to the upper surface side of the magnetic circuit 3, and 9 is a gasket.

FIG. 3 shows reproduced sound pressure frequency characteristics of the speaker (speaker described with reference to FIG. 2). In the figure, reference numeral 10 is the characteristic of the speaker , and reference numeral 11 is a conventional diaphragm (edge portion, The characteristics of the speaker using the diaphragm main body part is equal to 46μ). The measurement conditions are 0.1 W (1 kHz) input, and the distance between the speaker and microphone is 0.5 m. ing.

Further, the lowest resonance frequency of the speaker using the conventional diaphragm is about 500 Hz, but the lowest resonance frequency of the speaker using the diaphragm of the present invention is about 300 Hz, harmonic distortion is reduced, and vibration is reduced. It is possible to obtain a speaker that has a well-balanced body and little division resonance of the vibrating surface, has high sound quality, and has a wide reproduction frequency band.

The ratio t2 / t1 between the thickness t1 of the diaphragm body and the thickness t2 of the edge portion is 0.6 to 0.9.
When the ratio is less than 0.6, the moldability is deteriorated to cause quality variations, and when it is more than 0.9, no remarkable effect appears on the characteristics of the speaker.

( First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 shows a molding die for manufacturing the speaker diaphragm according to the embodiment, which is an upper die 12 shown in FIG. 4A and a lower die 13 shown in FIG. The upper die 12 and the lower die 13 each have an integral structure in which a surface of the diaphragm main body is formed on the surface of the upper die 12 and an edge of the outer die is formed with a corrugated cross section. Has been done.

In addition, a convex portion 12a having a size higher than at least the total height of the edge portion is provided in the upper die 12 in an annular shape at the boundary portion between the diaphragm main body molding portion and the edge portion molding portion. The recess 13 into which the portion 12a is fitted
a is provided in the lower die 13 in an annular shape.

Further, on the surface of the molded portion of the diaphragm main body,
Honing processing is applied, and the upper die 12 has a honing surface 12b.
The lower mold 13 forms a honing surface 13b.

A molding die having the above structure is prepared,
A polyethylene naphthalate film having a substrate thickness of 50 μm is heated in an atmosphere of a temperature of 180 to 200 ° C., and the heated film is placed on the lower mold 13 of the mold cooled to about 20 to 30 ° C. By lowering and applying pressure, a speaker diaphragm having a desired shape was prepared.

When the thickness of the diaphragm thus obtained was measured, the thickness of the edge portion was 42 μ, the thickness of the diaphragm body portion was 48 μ, and the thickness of the edge portion was thinner than that of the diaphragm body portion. The ratio was about 88%, and the minimum resonance frequency of the speaker using this diaphragm was about 400 Hz.

Further, the thickness of the edge portion of the diaphragm obtained by the manufacturing method according to the present embodiment is thinner than the thickness of the diaphragm main body is that the convex portion 12a and the concave portion 13a, the honing surface 12b, The effect of 13b is that when the preheated film is placed on the die, the die surface of the vibration plate main body molding portion is subjected to honing processing, so that the heating on the upper surface of this honing surface 13b is performed. The film has less slippage, and in addition to that, the mold is cooled to about 20 to 30 ° C. Therefore, the mold of the diaphragm body molding part first cools the heated film rapidly to reduce the elongation of the film. In order to form the edge part immediately after stretching the film of the edge part after making it worse,
Since the film is not cooled at the edge portion, the film is stretched well, and thus the thickness is thinner than that of the diaphragm main body portion.

Further, by providing the convex portion 12a and the concave portion 13a, it is possible to prevent the film from being drawn from the diaphragm main body portion to the edge portion when the above-mentioned edge portion is formed, and only the material of the edge portion has a corrugated cross section. The material is stretched to reduce the thickness in order to form an edge portion having a large developed area.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 5 shows a molding die for manufacturing the speaker diaphragm according to the present embodiment. The upper die 14 shown in FIG. 5A and the lower die shown in FIG. The upper mold 14 and the lower mold 15 are both composed of the diaphragm main body molding portions 14a and 15a and the edge molding portion 14
b and 15b are independently connected to each other in a divided structure, and a heater 16 is connected to the outer circumference of each.

Further, the diaphragm body molding portions 14a, 15
A material of thermosetting resin or silicone resin having good heat resistance or ceramic having poor heat conductivity is used for a, and a metal having good heat conductivity is used for the edge molding portions 14b and 15b. In this embodiment, it is preferable to use a thermosetting phenolic resin having good heat resistance for the vibration plate main body molding portions 14a and 15a, and the edge molding portion 14 is used.
A molding die was constructed by using iron materials having good thermal conductivity for b and 15b.

Using the molding die having the above structure, the edge portion molding portions 14b and 15b are heated by the heater 16 to 120.
A polyethylene naphthalate film having a substrate thickness of 50 μm, which is heated to ˜130 ° C. and heated in a temperature atmosphere of 180 to 200 ° C., is placed on the lower mold 15, and the upper mold 14 is lowered to apply pressure. A shaped speaker diaphragm was created.

When the thickness of the diaphragm thus obtained was measured, the thickness of the edge portion was 38 μ, the thickness of the diaphragm main body portion was 48 μ, and the thickness of the edge portion was smaller than the thickness of the diaphragm main body portion. The ratio was about 79%, and the minimum resonance frequency of the speaker using this diaphragm was about 380 Hz.

Also, the thickness of the edge portion of the diaphragm obtained by the manufacturing method according to the above embodiment is thinner than the thickness of the diaphragm main body is that the material having good thermal conductivity is used in combination with the material having bad thermal conductivity. The effect is that the molded parts 14b and 15b have good thermal conductivity and the heater 16
Since it is heated to 120 to 130 ° C at this point, the material placed on this part easily expands, and the diaphragm main body made of a material with poor thermal conductivity has a low mold surface temperature, so this part The material placed on the sheet has a relatively poor elongation, resulting in the above.

(Embodiment 3) A third embodiment of the present invention will be described below with reference to the drawings.

FIG. 6 shows a molding die for manufacturing the speaker diaphragm according to the present embodiment. The upper die 17 shown in FIG. 6A and the lower die shown in FIG. The upper die 17 and the lower die 18 are formed on the respective surface portions of the diaphragm main body portion and the edge portion formed on the outer peripheral portion thereof in an integral structure. There is. This edge portion forming portion is formed in a corrugated cross section in the lower die 18, and in the upper die 17, when the width of the edge portion forming portion of the lower die 18 is A, both sides (inner peripheral side and outer peripheral side)
A groove portion having a width dimension of A + 2T × (0.6 to 0.8) to which a dimension of 60% to 80% of the thickness T of the diaphragm material used for is added is provided.

In addition, a convex portion 17a having a size higher than at least the total height of the edge portion is provided in the upper die 17 in an annular shape at the boundary portion between the diaphragm main body molding portion and the edge portion molding portion. Recessed portion 18a into which the portion 17a fits
Is provided in the lower die 18 in an annular shape.

A molding die having the above structure is prepared,
A polyethylene naphthalate film having a substrate thickness of 50 μm is heated in an atmosphere of a temperature of 180 to 200 ° C., and the heated film is placed on the lower mold 18 of the mold cooled to about 20 to 30 ° C. By lowering 17 and applying pressure, a speaker diaphragm having a desired shape was prepared.

When the thickness of the diaphragm thus obtained was measured, the thickness of the edge portion was 35 μ, the thickness of the diaphragm main body portion was 48 μ, and the thickness of the edge portion was thinner than that of the diaphragm main body portion. The ratio is about 73%, the minimum resonance frequency of the speaker using this diaphragm is about 300 Hz, and the reproduced sound pressure frequency characteristic of this speaker uses the speaker diaphragm according to the present invention. Speaker
Sound pressure frequency characteristics (10 in FIG. 3).

The thickness of the edge portion of the diaphragm obtained by the manufacturing method according to the above-described embodiment is thinner than the thickness of the diaphragm body, because the edge portion of the upper die 17 of the molding die is formed. This is the effect of the groove portion, the convex portion 17a, and the concave portion 18a provided, and when the film is molded along the shape of the edge portion molding portion of the corrugated cross section provided in the lower mold 18, the groove portion, the convex portion 17a, and the concave portion 18a The film is prevented from being drawn into the edge portion from the diaphragm main body, and the material is stretched and thinned in order to form the edge portion having a large developed area of the cross-sectional corrugation only by the material of the edge portion.

In the above-described embodiment, the edge portion forming portion of the upper die 17 is provided with the groove portion, but the present invention is not limited to this, and instead of the groove portion, an edge portion shape having a corrugated cross section is used. Needless to say, it can be configured.

(Embodiment 4 ) A fourth embodiment of the present invention will be described below with reference to the drawings.

FIG. 7 shows a molding die for manufacturing the speaker diaphragm according to the present embodiment. The upper die 19 shown in FIG. 7A and the lower die shown in FIG. 20. The upper die 19 and the lower die 20 each have a surface structure in which a portion for molding the diaphragm main body portion and a portion for molding the edge portion formed on the outer peripheral portion are integrally structured. ing.

The molding die is composed of an upper die 19 and a lower die 20.
When the combination is made, the edge portion forming portion is in contact with the portion, and the portion forming the diaphragm main body portion has a size of 10 to 40% of the thickness of the resin film used as the diaphragm (in this embodiment, The clearance B is set to 30%).

A molding die having the above structure is prepared,
A polyethylene naphthalate film having a substrate thickness of 50 μ is heated in an atmosphere of a temperature of 180 to 200 ° C., and the heated film is placed on the lower mold 20 of the mold cooled to about 20 to 30 ° C. By lowering 19 and applying pressure, a speaker diaphragm having a desired shape was prepared.

When the thickness of the diaphragm thus obtained was measured, the thickness of the edge portion was 38 μ, the thickness of the diaphragm body portion was 47 μ, and the thickness of the edge portion was thinner than that of the diaphragm body portion. The ratio was about 81%, and the minimum resonance frequency of the speaker using this diaphragm was about 380 Hz.

Further, the thickness of the edge portion of the diaphragm obtained by the manufacturing method according to the above-described embodiment is formed thinner than the thickness of the diaphragm main body because the diaphragm main body is used as a diaphragm. This is due to the fact that the clearance B having a dimension of a ratio of 10 to 40% of the thickness of the resin film to be formed is provided, and the edge portion molding portion of the molding die first abuts and is strongly pressed and heated. Although the film is stretched, the molded portion of the diaphragm main body comes into contact later with the clearance B provided, and since it is not strongly pressed, it is finished thicker than the edge portion .

Although the polyethylene naphthalate film is used as the diaphragm material in the first to fourth embodiments, the present invention is not limited to this, and the diaphragm material is used as the diaphragm material. It goes without saying that a polyethylene terephthalate film or another resin film may be used.

[0045]

Method for manufacturing a speaker diaphragm according to the present invention as described above, according to the present invention may be made thinner than the material thickness of the diaphragm body portion wood thickness of the edge portion of the diaphragm using a resin film
The elongation of the resin film is large at the edge portion,
It is extremely easy to reduce the size of the diaphragm
The minimum resonance frequency of the speaker can be lowered by reducing the edge stiffness and the diaphragm main body is well-balanced with little division resonance of the vibrating surface, high sound quality, and the reproduction frequency band. It is possible to obtain a speaker diaphragm having a wide range of characteristics, which is of great industrial value.

[Brief description of drawings]

Half cross-sectional view showing a scan of speaker diaphragm structure of the present invention; FIG

Half cross-sectional view showing a speaker structure with Figure 2 diaphragm for the speaker

FIG. 3 is an output sound pressure reproduction frequency characteristic diagram comparing the characteristics of a speaker using a speaker diaphragm according to the present invention and a speaker using a conventional speaker diaphragm.

FIG. 4 is a half sectional view showing a molding die for obtaining the speaker diaphragm according to the first embodiment of the present invention.

FIG. 5 is a half sectional view showing a molding die for obtaining a speaker diaphragm according to a second embodiment of the present invention.

FIG. 6 is a half sectional view showing a molding die for obtaining a speaker diaphragm according to a third embodiment of the present invention.

FIG. 7 is a half sectional view showing a molding die for obtaining a speaker diaphragm according to a fourth embodiment of the present invention.

FIG. 8 is a half sectional view showing a molding die for molding a conventional speaker diaphragm.

FIG. 9 is a half sectional view showing a conventional speaker diaphragm.

[Explanation of symbols]

1 diaphragm 2 voice coils 3 magnetic circuit 4 York 5 magnets 6 plates 7 Magnetic gap 8 frames 9 gasket 10 Characteristics of speaker using diaphragm according to the present invention 12 Upper mold 12a convex part 12b, 13b Forming surface 13 Lower mold 13a recess 14 Upper mold 14a, 15a Molded portion of diaphragm main body 14b, 15b Edge part forming part 15 Lower mold 16 heater 17 Upper mold 17a convex part 18 Lower mold 18a recess 19 Upper mold 20 Lower mold

Front page continued (72) Inventor Shigeru Tomoeda 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP 60-100898 (JP, A) JP 58-71798 (JP, A) JP 63-263797 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04R 7/02 H04R 7/20 H04R 31/00

Claims (7)

(57) [Claims] 1. An edge portion is provided on a peripheral edge of a diaphragm main body portion,
The thickness of this edge is thinner than that of the diaphragm body.
Manufacture of speaker diaphragms made of resin film
Method, which is preheated to a temperature above the softening point
The thickness of the edge portion of the resin film
Elongate the elongation of the resin film so that it is thinner than the thickness.
So that it is large at the edge part and small at the diaphragm body part
Manufacture of speaker diaphragm that is pressed into desired shape
Method. 2. The thickness of the edge portion is greater than the thickness of the diaphragm main body portion.
The elongation of the resin film should be
A means to make it larger and smaller in the diaphragm body
Then, on the upper die of the molding die, the boundary between the edge and the diaphragm body
Formed in the boundary at least higher than the total height of the edge.
The ring-shaped protrusions are provided, and the recesses
It is provided in a ring on the mold and is heated in advance to a temperature above its softening point.
The molded resin film is shaped into the desired shape using the molding die described above.
A method for manufacturing a speaker diaphragm according to claim 1, wherein the method is pressure molding.
Law. 3. The thickness of the edge portion is greater than the thickness of the diaphragm main body portion.
The elongation of the resin film should be
A means to make it larger and smaller in the diaphragm body
To, claims a resin film which has been heated in advance above the softening point temperature of the upper and lower molds of the molding die applying honing portion for molding the diaphragm main body is pressure molded into a desired shape 1. The method for manufacturing a speaker diaphragm according to 1 . 4. The thickness of the edge portion is greater than the thickness of the diaphragm main body portion.
The elongation of the resin film should be
A means to make it larger and smaller in the diaphragm body
Then, on the upper die of the molding die, the boundary between the edge and the diaphragm body
Formed in the boundary at least higher than the total height of the edge.
The ring-shaped protrusions are provided, and the recesses
In addition to being provided in the mold in an annular shape, the resin film that has been heated to a temperature above the softening point of the upper mold and the lower mold is subjected to honing processing in the part that forms the diaphragm main body, and is heated to a temperature above the softening point in advance. The method for producing a speaker diaphragm according to claim 1, wherein the resin film is pressure-molded into a desired shape by the molding die. 5. The thickness of the edge portion is greater than the thickness of the diaphragm main body portion.
The elongation of the resin film should be
A means to make it larger and smaller in the diaphragm body
The edge of the molding die is made of thermosetting resin or silicone resin with good heat resistance or ceramic with low thermal conductivity. Using a metal mold with a high heat conductivity and a split structure that incorporates a heat source, a resin film that has been heated to a temperature equal to or higher than the softening point in advance with the edge portion of the metal mold being heated to the desired The method for manufacturing a speaker diaphragm according to claim 1, wherein the speaker diaphragm is shaped into a shape. 6. The thickness of the edge portion is greater than the thickness of the diaphragm main body portion.
The elongation of the resin film should be
A means to make it larger and smaller in the diaphragm body
Then , a groove portion having a width dimension of a dimension of 60 to 80% of the thickness of the resin film used as the vibration plate in the upper die of the molding die is added to the inner peripheral side and the outer peripheral side of the edge molding portion, respectively. The method for producing a speaker diaphragm according to claim 1, wherein the edge forming portion is provided with, and the resin film heated in advance to a softening point of the resin film or higher is pressure-molded into a desired shape by the molding die. 7. The thickness of the edge portion is greater than the thickness of the diaphragm main body portion.
The elongation of the resin film should be
A means to make it larger and smaller in the diaphragm body
Then, when the upper die and the lower die of the molding die are combined and the edge portion forming portion is brought into contact, the portion forming the diaphragm main body portion is 10 to 40% of the thickness of the resin film used as the diaphragm.
The vibration for a speaker according to claim 1, wherein the resin film, which is formed to have a clearance having a size of the above ratio and is heated in advance to a softening point of the resin film or higher, is pressure-molded into a desired shape by the molding die. Method of manufacturing a plate.