JP2001036997A - Method for manufacturing speaker edge - Google Patents

Abstract

(57) [Problem] To provide a manufacturing method capable of easily obtaining a speaker edge excellent in lightness, acoustic characteristics and durability. SOLUTION: A flexible polyurethane foam sheet 11 having a thickness of 6 to 25 mm is preheated and compressed by a flat plate 21 to 1.5
After making the flat compressed polyurethane foam sheet 12 having a thickness of about 4 mm, the flat compressed polyurethane foam sheet is cut into a ring shape, and the flat compressed polyurethane foam sheet 13 having the ring shape is then cut into a thickness of 0.6 to 0.6 mm.
It is further heated and compressed by a speaker edge mold 23 so as to be 1.0 mm and shaped into a speaker edge shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a speaker edge around a cone body (also referred to as a speaker diaphragm body).

[0002]

2. Description of the Related Art Generally, a speaker is, as shown in FIG.
The cone body 50 made of cone paper is held on the frame F via the speaker edge 60 provided on the periphery thereof, so that the vibration of the cone body 50 is not hindered. The shape of the speaker edge 60 is such that the inner peripheral edge 6 does not hinder the vibration of the cone body 50.
A bent portion 65 that is curved upward or downward in an arc shape in cross section is formed between the first and outer peripheral edges 63.

Conventionally, the speaker edge is manufactured by molding a foamed rubber composition in a mold, or by placing a cone body in a mold and placing a thermoplastic resin, such as acrylic or polycarbonate or thermoplastic resin, in the mold. Injection molding of molten resin such as polyurethane resin, or a polyurethane foam slab foamed into a block shape is cut out into a sheet of a predetermined thickness, and the polyurethane foam sheet is subjected to a single heat compression molding using a press die to make a speaker edge. There are things to shape.

However, the conventional method for manufacturing a speaker edge has the following problems. First, in the manufacturing method of molding a foamed rubber composition in a mold, the obtained speaker edge is heavy, so that when used in combination with the cone body, the mass of the vibration system becomes heavy and the sound pressure frequency characteristics deteriorate. There is. In addition, the rubber speaker edge has a problem that requires a high level of technology when bonding to the cone body.

[0005] Further, in a manufacturing method in which a thermoplastic resin is melted and injection molded, the temperature of the molten resin is 200 to 3
Since it is extremely high at about 00 ° C., there is a problem that the cone body is easily damaged by heat when integrally molded with the cone body in a mold.

In the method of manufacturing a polyurethane foam sheet by one heat compression molding, the outside (convex side) of the bent bases 66 and 67 of the speaker edge shown in FIG. 4 is heated by a press mold. When compressed, it is greatly stretched to have a low density, and the opposite inner side (concave side) is compressed almost without being stretched to have a high density. Such non-uniform density on the speaker edge surface causes a decrease in strength. Therefore, it is not preferable in the durability of the speaker edge and the like. In particular, as for the speaker edge, the inner peripheral side of the speaker edge 60 vibrates together with the peripheral edge of the cone body 50, and the outer peripheral side of the speaker edge 60 is restrained by the frame F, so that the fatigue concentrates on the bent base 67 on the frame side. As a result, it was difficult to say that the strength of the base portion of the bent portion was sufficient in the speaker edge obtained by the one-time heat compression molding as described above.

[0007] As another manufacturing method, a plurality of elongated pieces made of a porous foamed resin sheet are overlapped on the short sides thereof, and are heat-formed into a ring shape by a mold, so that the overlapped portion is formed. A method has also been proposed in which a ring-shaped edge-finished product is formed by heat welding and then heated and formed by an edge forming die to form a speaker edge. However, in this case, the obtained speaker edge has a higher density and rigidity at the overlapping portion of the elongated pieces than at the other non-overlapping portions, impairs flexibility, and produces an acoustic sound at the time of audio output of the speaker. Not only does it adversely affect the characteristics, but also has an adverse effect on strength durability.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a manufacturing method capable of easily obtaining a speaker edge having excellent lightness, acoustic characteristics and durability. .

[0009]

That is, according to the first aspect of the present invention, a flexible polyurethane foam sheet having a thickness of 1.5 to 4 mm is obtained by preheating and compressing a flexible polyurethane foam sheet having a thickness of 6 to 25 mm with a flat plate. Then, the flat compressed polyurethane foam sheet is cut into a ring shape, and then the flat compressed polyurethane foam sheet having the ring shape is further molded with a speaker edge mold so as to have a thickness of 0.6 to 1.0 mm. The present invention relates to a method for manufacturing a speaker edge, wherein the speaker edge is shaped by heating and compression.

The invention according to claim 2 is characterized in that the ring-shaped cutting is performed by:
It is characterized in that it is performed after the heat compression molding by the speaker edge mold. Further, the invention of claim 3 is characterized in that the flexible polyurethane foam sheet is preliminarily cut into an annular shape and then subjected to preheating compression molding.

Further, in the invention according to claim 4, the flexible polyurethane foam sheet according to claims 1 to 3 has a density of 2
0 to 60 kg / m ³ .

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a manufacturing process diagram showing an outline of a manufacturing method according to an embodiment of the present invention, and FIG.
FIG. 3 is a manufacturing process diagram showing an outline of a manufacturing method according to an embodiment of the present invention, and FIG. 3 is a manufacturing process diagram showing an outline of a manufacturing method according to an embodiment of the present invention.

First, an embodiment of the present invention will be described. FIG. 1 is a diagram showing a manufacturing process according to the embodiment, and includes a preheating compression molding process, a cutting process, and a final heating compression process.

In the preheating compression molding step, as shown in FIG. 1A, a flexible polyurethane foam sheet 11 having a thickness of 6 to 25 mm is preheated and compressed by a flat plate 21 to obtain a thickness of 1.
A 5 to 4 mm flat compressed polyurethane foam 12 is formed.

The flexible polyurethane foam sheet 11 comprises:
6-25 thickness from flexible polyurethane foam slab
What is cut into a sheet of mm is used. Thickness 6 ~
The reason why the thickness is set to 25 mm is that the acoustic characteristics of the speaker and the durability of the speaker edge are improved in consideration of the degree of compression in the preheating compression and the final heating compression. The planar shape of the flexible polyurethane foam sheet 11 may be any shape as long as it is larger than the intended speaker edge, such as a square or a circle. The density of the flexible polyurethane foam sheet 11 is preferably 20~60kg / ^{m 3.} By setting the density in this range, a speaker edge having more excellent acoustic characteristics, durability and lightness can be obtained.

The flat plates 21 and 21 have flat surfaces facing each other and are made of metal or the like, and have such a size that the soft urethane foam sheet 11 can be sandwiched between the flat surfaces. The flat plate 21 is connected to a heating means (not shown) such as an electric heater to be heated, and is connected to a known press device (not shown) so that the flexible polyurethane foam sheet 11 can be compressed into a flat plate shape. It has become. The heating and compression conditions at this time are as follows: a heating temperature of 180 to 240 ° C. and a compression time of 10 to 120 seconds, and particularly 190 ° C. to 210 ° C. and 15 to 30 seconds. This is preferable because the shape can be fixed well.

When the flexible polyurethane foam sheet 11 is compressed into a flat plate by the preheating compression molding, the flexible polyurethane foam sheet 11 is uniformly compressed by the flat plate 21. The uniformity of the density is high.

In the subsequent cutting step, the flat compressed polyurethane foam sheet 12 is cut into a ring shape corresponding to the size of the speaker edge by a cutting tool 22 such as a Thomson blade as shown in FIG. A ring-shaped compressed polyurethane foam sheet 13 is formed. At this time, the flat compressed polyurethane foam sheet 12
Since the density has already been increased and the rigidity has been appropriately increased by pre-heating and compression molding, deformation at the contact point with the cutting blade is reduced, and it can be cut accurately, so that it finally becomes the speaker edge The dimensional accuracy at the time of is increased.

In the final heat compression molding step, as shown in FIG. 1 (c), the annular compressed polyurethane foam sheet 13 is formed into a speaker edge mold 23 having a speaker-edge-shaped uneven surface. Heat compression molding is carried out, and it shape | molds to the speaker edge of thickness 0.6-1.0mm. The heating compression conditions are in the same range as in the preheating compression molding. In this step, since the flat compressed polyurethane foam sheet 13 having the ring shape is already thinner than the original thickness by the preheating compression molding, it follows the unevenness of the speaker edge mold 23 well, and Since the difference in the amount of elongation between the inner surface and the outer surface of the bent portion formed into the concave portion or the convex portion is small, the density obtained by compression becomes high. The compression to a thickness of 0.6 to 1.0 mm is a value set so that the speaker has good acoustic characteristics and the durability of the speaker edge is good.

The loudspeaker edge 10 obtained as described above is excellent in lightness. Then, when used after being fixed to the outer peripheral edge of the loudspeaker cone body, the loudspeaker edge 10 has excellent acoustic characteristics and durability. It has an excellent effect.

FIG. 2 is a manufacturing process diagram showing an outline of a manufacturing method according to an embodiment of the present invention. This embodiment comprises a pre-heating compression molding step, a final heating compression molding step, and a cutting step, and is otherwise the same except that the point at which the cutting step is performed is different from that of the first aspect of the present invention.
The same components as those in the above-described embodiment are denoted by the same reference numerals.

In the preheating compression molding step shown in FIG. 2 (a), the flexible polyurethane foam sheet 11 is preheated and compressed by the flat plate 21 in the same manner as in the embodiment of the first aspect of the present invention. Is formed.

In the subsequent final heat compression molding step, FIG.
As shown in (b), the flat compressed polyurethane foam sheet 11 is heated and compression-molded by a speaker edge mold 23, and shaped into a speaker edge shape to obtain a speaker edge shaped product 10a. The heating and compression conditions are:
This is the same as the embodiment of the first aspect of the present invention. As the speaker edge mold 23, a mold having the same mold surface as the first aspect of the invention can be used. In that case, the speaker edge shaped article 1 that is to be cut and removed in a subsequent cutting step
The central portion and the outer peripheral portion of Oa may not be compressed or may be less compressed.

In the cutting step shown in FIG. 2C, the cutting edge 22 of the uncut speaker edge shaped article 10a obtained in the final heating compression molding step is used by the cutting tool 22 to make the center and outer periphery unnecessary for the speaker edge. The portion is cut and removed to obtain a desired speaker edge 10. As described above, since the cutting step is performed after shaping into the speaker edge shape, the dimensions of the obtained speaker edge tend to be accurate.

FIG. 3 is a manufacturing process diagram showing an outline of a manufacturing method according to an embodiment of the present invention. In this embodiment, a cutting step, a preheating compression molding step, and a final heating compression molding step are performed.
And 2 are the same. The same components as those of the above embodiment are denoted by the same reference numerals.

In this embodiment, a cutting step is first performed. In the cutting step, as shown in FIG. 3 (a), a flexible urethane foam sheet 11 cut from a flexible polyurethane foam slab into a sheet having a thickness of 6 to 25 mm is formed into a ring shape corresponding to the target speaker edge. Cutting is performed with a cutting tool 22 such as a blade to form a ring-shaped flexible polyurethane foam sheet 11a.

In the subsequent preheating compression molding step, FIG.
As shown in (b), the ring-shaped flexible polyurethane foam sheet 11a is preliminarily heated and compression-molded on the flat plate 21 to form a ring-shaped compressed polyurethane foam sheet 13 having a thickness of 1.5 to 4 mm. At this time, a flat compressed polyurethane foam sheet 1 having a ring shape is used.
3 is economical because the unnecessary portions of the central portion and the outer periphery have already been cut off, and the cut-out portion can be prevented from being heated or compressed. The heating and compression conditions at this time are the same as those of the first embodiment of the present invention.

In the final heat compression molding step, as shown in FIG. 3C, the ring-shaped flat compressed polyurethane foam sheet 13 is heated and compressed by a speaker edge mold 23 to form a speaker edge shape. Then, a desired speaker edge 10 is obtained. The heating and compression conditions at this time are the same as those in the final heating and compression molding step in the first embodiment.

[0029]

EXAMPLES Specific examples of the present invention and comparative examples for reference are shown below. Example 1 A slab of a flexible polyurethane foam having a density of 33 kg / m ³ was cut into a thickness of 8 mm to obtain a plane dimension of 160 × 140 m.
m, and a single sheet of flexible polyurethane foam sheet is placed between flat iron plates heated to 200 ° C.
This was preheated and compressed for 2 seconds to obtain a 2 mm-thick flat-plate compressed polyurethane foam sheet. At that time, a spacer having a thickness of 2 mm was arranged at the edge between the iron plates so that the gap between the iron plates was 2 mm.

Thereafter, the flat compressed polyurethane foam sheet was cut into an annular shape having an inner diameter of 80 mm and an outer diameter of 140 mm with a Thomson blade to obtain an annular flat compressed polyurethane foam sheet. Next, the flat compressed polyurethane foam sheet having the ring shape is placed in a speaker edge mold having an uneven surface corresponding to the speaker edge shape, and is finally heated and compressed to have a thickness of 0.8 mm and a roll diameter of 0.8 mm. 4 mm, roll inner diameter; 10
7 mm, outer diameter of roll; 125 mm, overall height of roll; 6.4
mm speaker edge was obtained. The heating and compression conditions were as follows: total pressure 1 ton, mold temperature 210 ° C, press time 15
Seconds.

Example 2 A loudspeaker was produced in the same manner as in Example 1 except that the thickness of the spacer disposed between the iron plates in Example 1 was changed to 3 mm, and a flat compressed polyurethane foam sheet having a thickness of 3 mm was formed. An edge was formed. The thickness and other dimensions of the speaker edge are the same as those in the first embodiment.

Comparative Example 1 The flexible urethane foam sheet obtained by cutting the slab of the flexible polyurethane foam having a density of 33 kg / m ³ used in the examples to a thickness of 8 mm was obtained without preheating and compression.
It was directly heated and compressed to a thickness of 0.8 mm with a speaker edge mold to form a speaker edge of Comparative Example 1. that time,
For the speaker edge mold, use the mold used in the embodiment,
The heating and compression conditions were the same as in the example except that the pressing time was set to 20 seconds.

Comparative Example 2 The loudspeaker edge of Comparative Example 2 was prepared under the same conditions as Comparative Example 1 except that the flexible polyurethane foam slab having a density of 33 kg / m ³ used in the example was cut to a thickness of 12 mm. Molded.

A tensile strength test, a durable acoustic test, and a cold acoustic test were performed on the above Examples and Comparative Examples as follows, and the cross section of the bent portion (corner portion) was photographed with an electron microscope to determine the density of the resin. I checked the condition. Table 1 shows the results.

The tensile strength was measured on an Ω-shaped test piece obtained by cutting a 10 mm width with the circumferential direction of the speaker edge as the width direction and a length of 25 mm between both ends with the radial direction as the length direction. Both ends of the chuck of the tensile tester (1 between chucks)
0 mm) and pulled so as to expand both ends. The measurement of the tensile strength is based on JIS-K
I copied it to -7127.

In the endurance acoustic test, the voice coil diameter was 26.2.
mm, an outer diameter of 106 mm, and a weight of 3.3 g of a polypropylene cone body (cone paper) were joined to the speaker edges of the example and the comparative example, and a speaker having the same voice coil and the same magnetic circuit (manufactured by Matsushita Electronic Components Co., Ltd. Speaker part number "E
AS14P124AR2 ”), a music source was input at a peak input level of 50 W and an average level of 25 W, and a continuous operation test at room temperature for 96 hours was performed to determine whether or not cracks occurred. In addition, the cold-resistant acoustic test
The same configuration as the endurance acoustic test was applied, a rated input of 15 W of white noise was applied at −40 ° C., and a continuous operation test was performed for 96 hours to check whether or not cracks occurred.

[0037]

[Table 1]

From the above measurement results, it can be seen that the loudspeaker edge of each example has a higher tensile strength than the loudspeaker edge of Comparative Example 1, and has excellent durability in the durability acoustic test and the cold acoustic test. In Comparative Example 2, the thickness of the urethane foam sheet was increased to 10 mm to increase the resin strength in order to prevent the edge from cracking. However, cracks occurred in the cold acoustic test, and the durability at low temperatures was improved. It was found that no effect was obtained.

From electron micrographs (not shown) of the cross section of the speaker edge, in Examples 1 and 2, even at the bent portion (corner portion), the resin was almost uniformly dispersed over the entire edge. Was confirmed.
On the other hand, in Comparative Examples 1 and 2, there were a portion where the resin was dense and a portion where the resin was sparse at the bent portion of the edge. It is considered that the unevenness of the resin adversely affects durability and sound. In particular, in Comparative Example 2, it was found that the density of the resin was not improved even though the thickness was increased.

[0040]

As shown and described above, according to the first to third aspects of the present invention, the flexible polyurethane foam sheet is preheated and compressed by a flat plate. When pressure is applied, the obtained flat compressed polyurethane foam sheet has high uniformity in density. In addition, since there is no overlapping portion, the density does not partially increase. Therefore, durability and acoustic characteristics are improved. Further, since one flexible polyurethane foam sheet may be pre-heated and compressed with a flat plate, a plurality of elongated pieces are overlapped at the ends to form a ring, and placed between the mold surfaces while being heated and compressed. It is not necessary to pay attention to the amount and the displacement, and the operation is simplified.

In the preheating compression, the thickness is 6 to 25 m.
1.5 to 4 mm
Since the sheet is compressed to a thickness, the obtained flat compressed polyurethane foam sheet has appropriate flexibility required for subsequent heat compression molding using a speaker edge mold. In addition, since the flat compressed polyurethane sheet whose thickness has been reduced by pre-heating and compression is shaped into the uneven shape of the speaker edge by the speaker edge mold, the shape is deformed between the convex outside and the concave inside during the shaping. The difference in the amount becomes small and unevenness in the density is less likely to occur, and the adverse effects of the acoustic characteristics and durability due to the unevenness in the density can be reduced.

In addition to these effects, in the inventions according to the first to third aspects, since the points at which the ring is cut into a ring shape are different, the following operations and effects are exhibited. First, in the invention of claim 1, a flat compressed polyurethane sheet whose density is increased by preheating compression and shape retention is increased,
Since the operation of cutting into a ring shape is performed, the flat compressed polyurethane sheet is not easily twisted or distorted during the cutting operation, and can be cut accurately. Therefore, it is suitable for manufacturing a wide range of speaker edges from small to large.

According to the second aspect of the present invention, the unnecessary portion is cut into a ring shape after heating and compression shaping by the speaker edge mold, so that the speaker edge mold performed before the cutting step is used. At the time of heating and compression, the flat compressed urethane foam sheet remains as it is, and the flat compressed urethane foam sheet hardly undergoes deformation such as twisting when placed in the speaker edge mold, and the work is easy.
Furthermore, since cutting is performed after shaping into a speaker edge shape, a speaker edge with high dimensional accuracy can be obtained. Therefore, it is suitable for manufacturing a type in which the urethane foam sheet is likely to be twisted when the urethane foam sheet is arranged in the speaker edge mold, for example, a large speaker edge.

On the other hand, in the invention of claim 3,
Since it is first cut into a ring shape and then preheat-compression molded, unnecessary portions need not be preheat-pressed, which is economical. In this case, in order to form the flexible polyurethane foam sheet into a ring shape at the time of high flexibility before the preheating compression, a type in which deformation and torsion are less likely to cause a problem during the subsequent laying operation for preheating molding, for example, a small speaker Suitable for manufacturing edges.

Further, the flexible polyurethane foam sheet to be used may have a density of 20 to 60 kg.
/ M ³ , it is possible to obtain a speaker edge having better acoustic characteristics and durability.

[Brief description of the drawings]

FIG. 1 is a manufacturing process diagram showing an outline of a manufacturing method according to an embodiment of the present invention.

FIG. 2 is a manufacturing process diagram showing an outline of a manufacturing method according to an embodiment of the present invention.

FIG. 3 is a manufacturing process diagram showing an outline of a manufacturing method according to an embodiment of the present invention;

FIG. 4 is a partially cutaway perspective view of a general speaker cone.

[Explanation of symbols]

REFERENCE SIGNS LIST 10 speaker edge 10 a speaker edge shaped product before cutting 11 flexible polyurethane foam sheet 11 a ring-shaped flexible polyurethane foam sheet 12 flat compressed polyurethane foam sheet 13 flat compressed polyurethane foam sheet having ring shape 21 flat plate 22 cutting tool 23 Mold for speaker edge

Continuing from the front page (72) Inventor Shinya Kaneko 3-1-36 Imaikecho, Anjo-shi, Aichi Prefecture Inoac Corporation Anjo Office (72) Inventor Kiyoshi Ikeda 1006 Kadoma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Yuko Yamazaki 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. 5D016 AA15 CA03 EC10 FA01 GA03 HA07 JA03

Claims (4)

[Claims] A flexible polyurethane foam sheet having a thickness of 6 to 25 mm is preheated and compressed by a flat plate to a thickness of 1.5 to 4 mm.
After forming the flat compressed polyurethane foam sheet having a thickness, the flat compressed polyurethane foam sheet is cut into a ring shape, and then the flat compressed polyurethane foam sheet having the ring shape has a thickness of 0.6 to 1.0 mm. A method of manufacturing a speaker edge, wherein the shape is further heated and compressed in a speaker edge mold to form a speaker edge shape. 2. A flexible polyurethane foam sheet having a thickness of 6 to 25 mm is preheated and compressed by a flat plate to a thickness of 1.5 to 4 mm.
After the thickness of the flat compressed polyurethane foam sheet is reduced to 0.
A speaker edge which is further heated and compressed by a speaker edge mold so as to have a width of 6 to 1.0 mm and shaped into a speaker edge shape, and then unnecessary portions of the shaped product are cut into a ring shape. Manufacturing method. 3. A flexible polyurethane foam sheet having a thickness of 6 to 25 mm is cut into a ring shape, and the flexible urethane foam sheet having the ring shape is preheated and compressed with a flat plate to form a ring having a thickness of 1.5 to 4 mm. Then, the flat compressed polyurethane foam sheet having the ring shape is further heated and compressed in a speaker edge mold so as to have a thickness of 0.6 to 1.0 mm. A method for manufacturing a speaker edge, comprising: 4. The method according to claim 1, wherein the flexible polyurethane foam sheet has a density of 20 to 60 kg / m ³ .