JP3698295B2 - Speaker unit and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a speaker unit. More specifically, the present invention relates to a speaker unit that has excellent vibration transmission characteristics, is inexpensive and has excellent manufacturing efficiency.
[0002]
[Prior art]
FIG. 6 is a schematic cross-sectional view for explaining a conventional speaker unit. This speaker unit has a diaphragm 4, an edge 2, and a gasket 5 that are separate from each other. An edge 2 of the edge 2 is fixed to the annular flange 1 a of the frame 1 via a washer 3. The inner peripheral edge 2b of the edge is affixed to the diaphragm 4 via an adhesive. Further, a gasket 5 is bonded on the outer peripheral end 2 a of the edge 2. In addition, arrow rubber or reinforcing paper may be used for the gasket portion.
[0003]
[Problems to be solved by the invention]
However, since such a speaker is formed by bonding the diaphragm, the edge, and the gasket, which are separate from each other, a portion where the internal loss is discontinuous is generated at the pasted portion. As a result, vibration is reflected at the pasted portion, so that the conventional speaker has a very large problem from the viewpoint of acoustic characteristics. Furthermore, such a speaker has a large number of parts. As a result, such a speaker also has problems such as high cost, a large number of manufacturing processes, and low manufacturing efficiency.
[0004]
The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a speaker unit that has excellent vibration transmission characteristics, is inexpensive, and has excellent manufacturing efficiency. is there.
[0005]
[Means for Solving the Problems]
The speaker unit of the present invention includes a diaphragm portion, an edge portion, and a gasket portion, and the foaming ratio of the gasket portion increases asymptotically from the edge portion side toward the outside, so that the edge portion and the edge portion The gasket portion is integrally molded from the foamed elastic material; the foaming ratio of the edge portion at the joint portion between the diaphragm portion and the edge portion is asymptotic from the edge portion side toward the main body portion side of the diaphragm. Thus, the diaphragm portion and the edge portion are closely fixed by hot pressing.
[0006]
In a preferred embodiment, the thickness of the joint is the same as the thickness of the main body portion of the diaphragm.
[0007]
According to another aspect of the present invention, a method for manufacturing a speaker unit is provided. The manufacturing method includes a step of forming a diaphragm portion having a cross-sectional thickness that decreases asymptotically toward a peripheral portion; and an expansion ratio of the gasket portion asymptotically increases from the edge portion side toward the outside. The edge portion and the gasket portion are integrally molded from the foamed elastic material, and the foaming ratio of the edge portion at the joint portion between the diaphragm portion and the edge portion is directed from the edge portion side toward the main body portion side of the diaphragm. A step of closely fixing the diaphragm portion and the edge portion by hot pressing so as to decrease asymptotically.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic cross-sectional view of a speaker unit according to a preferred embodiment of the present invention. The speaker unit 100 includes a diaphragm portion 14, an edge portion 12, and a gasket portion 15.
[0009]
Edge portion 12 and gasket portion 15 are integrally formed from any suitable foamed elastic material. Typical examples of the foamed elastic material include foamed rubber and polyurethane. Foam rubber is preferred because of its large internal loss. The expansion ratio of the gasket portion 15 increases asymptotically from the edge portion 12 side toward the outside. The expansion ratio only needs to increase asymptotically toward the outside, and the method of increase is not particularly limited. As the expansion ratio of the gasket portion 15 increases asymptotically, the internal loss also changes continuously. As a result, the vibration transmitted through the edge portion 12 without being damped is attenuated by the gasket portion, and the reflection of the vibration is reduced. It is because it becomes difficult to occur.
[0010]
FIG. 2 is an enlarged cross-sectional view of the joint portion 20 between the diaphragm portion 14 and the edge portion 12. As shown in FIG. 2, the outer peripheral end portion 14 a of the diaphragm portion 14 has a tapered cross-sectional shape whose thickness continuously decreases toward the outside (edge portion side). In the present invention, the material for forming the diaphragm portion 14 is not particularly limited, and any appropriate diaphragm material can be used. Considering the moldability of the tapered cross section and the adhesion to the edge portion, a silk nonwoven fabric impregnated with a thermosetting resin (for example, an unsaturated polyester resin) is preferable.
[0011]
Further, the expansion ratio of the edge portion 12 (that is, the edge inner peripheral end portion 12 b) in the joint portion 20 is asymptotically decreased from the edge portion 12 side toward the main body portion of the diaphragm 14. The outer peripheral end portion 14a and the edge inner peripheral end portion 12b of the diaphragm portion 14 are closely fixed by a hot press without any adhesive. As in the case of the gasket portion, the expansion ratio of the edge inner peripheral end portion 12b only needs to be asymptotically reduced toward the diaphragm portion 14, and the manner of reduction is not particularly limited. If the expansion ratio of the edge inner peripheral end portion 12b is continuously changed, it is equivalent to the vibration propagation medium continuously changing in the joint portion 20. Therefore, the vibration from the vibration plate portion 14 is satisfactorily attenuated at the joint portion 20, and the reflection of vibration is less likely to occur. From the viewpoint of suppressing the vibration propagation gap due to the difference in material, it is preferable that the cross-sectional thickness of the joint portion 20 is the same as the cross-sectional thickness of the main body portion of the diaphragm 14 as shown in FIG. Furthermore, it is preferable that the expansion ratio changes as slowly as possible (for example, the angle α in FIG. 2 is preferably 1 to 5 degrees, more preferably 2 to 3 degrees).
[0012]
Next, a preferable example of the method for manufacturing the speaker unit of the present invention will be described.
[0013]
First, the diaphragm portion 14 having a predetermined shape (for example, cone shape) is formed by any appropriate method. At that time, the outer peripheral end portion 14a of the diaphragm portion 14 is formed in a tapered shape whose cross-sectional shape asymptotically decreases toward the peripheral portion.
[0014]
Next, the edge portion 12 and the gasket portion 15 are integrally molded from the foamed elastic material so that the expansion ratio of the gasket portion 15 increases asymptotically from the edge portion 12 side toward the outside, and at the same time, the edge at the joint portion 20 is formed. The expansion ratio of the portion (that is, the edge inner peripheral end portion 12b) is gradually reduced from the edge portion 12 side toward the main body portion 14 side of the diaphragm so that the diaphragm outer peripheral end portion 14a and the edge inner periphery The end 12b is closely fixed by hot pressing. Specifically, (i) a mold having a predetermined inclined surface so as to obtain the edge inner peripheral end portion 12b and the gasket portion 15 having a desired foaming ratio is prepared; Position to obtain expansion ratio and place the diaphragm part (eg molding cone) in the lower mold of this mold; (iii) Place the foamed elastic material in the lower mold; (iv) Any suitable Hot pressing under various conditions to perform molding and foaming simultaneously. The foamed elastic material flows in the mold by hot pressing and comes into contact with the outer peripheral edge 14a of the diaphragm, and is pressed and adhered by foaming. Typically, the heating temperature (mold temperature) is 110 to 150 ° C., and the heating time is 30 to 50 seconds. According to such a manufacturing method, it is possible to precisely control the foaming ratio of a predetermined portion simply by changing the shape of the mold.
[0015]
【Example】
(Example 1)
A speaker unit as shown in FIGS. 1 and 2 was produced. Here, the angle α in FIG. 2 was set to 2.75 degrees. The back electromotive force and frequency characteristics when the obtained speaker unit was placed on the floor and struck with a metal rod were measured. The results are shown in FIG.
[0016]
(Comparative Example 1)
A speaker unit as shown in FIG. 6 was produced. However, an arrow rubber was provided instead of the gasket 5. The back electromotive force and frequency characteristics when the obtained speaker unit was placed on the floor and struck with a metal rod were measured. The results are shown in FIG.
[0017]
(Comparative Example 2)
A speaker unit was produced in the same manner as in Comparative Example 1 except that there was no arrow rubber. The back electromotive force and frequency characteristics when the obtained speaker unit was placed on the floor and struck with a metal rod were measured. The results are shown in FIG.
[0018]
As is clear from comparison between FIG. 3, FIG. 4 and FIG. 5, the speaker unit of the present invention has less time-dependent back electromotive force fluctuation than the conventional speaker unit, and particularly in the high frequency region. Have good frequency characteristics.
[0019]
【The invention's effect】
According to the present invention, the gasket portion and the edge portion are integrally formed while controlling the expansion ratio of the gasket portion, and the edge portion and the diaphragm portion are closely fixed by heat press while controlling the expansion ratio of the edge portion. By doing so, a speaker unit having very little vibration reflection and excellent vibration transmission characteristics (and consequently excellent acoustic characteristics) can be obtained. Furthermore, this speaker unit is low in cost because it has a small number of parts, and has a small number of processes and excellent manufacturing efficiency because it performs foaming and adhesion fixing by hot pressing in one process.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a speaker unit according to a preferred embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of a joint portion in the speaker unit of FIG.
FIG. 3A is a graph showing the measurement result of the back electromotive force for the speaker unit of the present invention; FIG. 3B is a graph showing the frequency characteristics of the speaker unit of the present invention.
FIG. 4A is a graph showing measurement results of back electromotive force for a conventional speaker unit; FIG. 4B is a graph showing frequency characteristics of the conventional speaker unit.
FIG. 5A is a graph showing measurement results of back electromotive force for a conventional speaker unit; FIG. 5B is a graph showing frequency characteristics of the conventional speaker unit.
FIG. 6 is a schematic cross-sectional view of a conventional speaker unit.
[Explanation of symbols]
12 Edge portion 12b Edge inner peripheral end portion 14 Diaphragm portion 14a Diaphragm outer peripheral end portion 15 Gasket portion 20 Joint portion 100 Speaker unit

Claims (3)

A speaker unit comprising a diaphragm part, an edge part and a gasket part,
The edge portion and the gasket portion are integrally formed from a foamed elastic material so that the expansion ratio of the gasket portion increases asymptotically from the edge portion side toward the outside, and
The expansion ratio of the edge portion at the joint between the vibration plate portion and the edge portion is gradually reduced from the edge portion side toward the main body portion side of the vibration plate, so that the vibration plate portion and the edge The part is firmly fixed by heat press,
Speaker unit. The speaker unit according to claim 1, wherein a thickness of the joint portion is the same as a thickness of a main body portion of the diaphragm. Forming a diaphragm portion having a cross-sectional thickness that decreases asymptotically toward the periphery;
The foaming ratio of the gasket part increases asymptotically from the edge part side to the outside, and the edge part and the gasket part are integrally formed from the foamed elastic material, and the diaphragm part and the edge part are joined to each other. A step of closely fixing the diaphragm part and the edge part by hot pressing so that the expansion ratio of the edge part in the part gradually decreases from the edge part side toward the main body part side of the diaphragm; The manufacturing method of the speaker unit containing this.

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