JP5272592B2 - Manufacturing method of speaker diaphragm, speaker diaphragm manufactured by the manufacturing method, and speaker using the speaker diaphragm - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a speaker diaphragm which is used in various acoustic devices, which excels in waterproofness or fire retardant nature, has a large degree of freedom for coordination of the tone quality, and can be manufactured with high productivity. <P>SOLUTION: In the manufacturing method for the speaker diaphragm, denaturation process for denaturalizing hydroxyl group contained in cellulose of natural fiber by chemical reaction is placed before or after the material fiber loosening process. Thus, the manufacturing time of a paper-made speaker diaphragm can be shortened, while achieving excellent waterproofness and fire retardant nature of the paper-made speaker diaphragm manufactured. The paper-made speaker diaphragm having excellent characteristics and large degree of freedom for coordination of the tone quality as a speaker can be manufactured with high productivity inexpensively. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for manufacturing a speaker diaphragm used in various acoustic devices and a speaker diaphragm manufactured by the manufacturing method.

  With respect to recent electronic equipment such as audio equipment and video equipment, the performance has been dramatically improved as compared with the prior art due to remarkable progress in digital technology.

  Therefore, due to the improvement in performance of the electronic devices described above, there is a strong demand from the market to improve the performance of speakers used in these electronic devices.

  On the other hand, for a speaker whose performance is strongly demanded by the market, it is indispensable to improve the performance of a diaphragm that occupies a large weight that determines the sound quality among the components of the speaker.

  As part of improving the performance of these diaphragms, the creation of sound and characteristics that satisfy the user needs required for each field and for each application are very important.

  It is the papermaking diaphragm that has the advantage that the characteristics and sound quality of the speaker can be finely adjusted that can produce sound and characteristics that satisfy these user needs, and the development of this papermaking diaphragm is drawing attention.

And for these papermaking diaphragms, the market demand for lower prices is remarkable,
In particular, market demands for high performance in terms of environmental resistance, quality, and reliability, such as imparting flame retardancy and waterproofness, are remarkable.

  A conventional method for manufacturing a papermaking diaphragm will be described with reference to FIG.

  FIG. 6 is a process chart showing a conventional method for manufacturing a speaker paper diaphragm.

  As shown in FIG. 6, the material of the speaker paper diaphragm is put into a beater containing water and beaten finely by a beating process over several days.

  Next, the beaten material is drawn up on a mold and a metal mesh disposed thereon by a paper making process, and only moisture is discharged, and the material is deposited to form a shape as a speaker diaphragm.

  Next, in the pressurizing step, the deposited speaker diaphragm material is heated and pressurized to evaporate the remaining water.

  Next, an unnecessary outermost peripheral portion and a central hole portion for inserting the voice coil are punched by a die by a punching process.

  Thus, a conventional speaker papermaking diaphragm is completed.

  The press diaphragm process has been described above, but there is also a manufacturing method as a so-called non-press diaphragm that is not pressed and dried for about one to two days.

  These papermaking diaphragms are often required to have heat resistance, flame retardancy, and waterproofness.

For example, Patent Document 1 is known as prior art document information relating to the invention of this application.
JP-A 62-196999

  While the audio and video industries have achieved dramatic performance improvements due to the significant advances in digital technology described above, their products tend to be low-priced and are used in electronic equipment such as audio and video equipment. The market demand for lowering the price is also remarkable.

  The conventional loudspeaker diaphragm that can satisfy user needs is mainly a papermaking diaphragm formed by making a pulp material.

  Thus, although it is a papermaking diaphragm that can satisfy user needs, in order to actually commercialize it, it is necessary to ensure waterproofness and flame retardancy as necessary processes because of the papermaking diaphragm.

  In particular, it is very difficult to impart waterproofness and flame retardancy to a papermaking diaphragm, and it is applied to a diaphragm made of fluororesin or hydrocarbon resin by dipping or spraying. The current situation is.

  In this case, due to the volatilization of the solvent and the like, the coating amount variation and the coating position variation are very large, and the performance variation is also large.

  The present invention solves the above-mentioned problems, and provides a method for manufacturing a speaker diaphragm that utilizes natural fibers modified in the previous step, instead of applying a waterproofing agent or a flame retardant later. It is the purpose.

  In other words, the natural paper itself is chemically modified to provide waterproofness and flame retardancy, and the speaker papermaking diaphragm with a high degree of freedom in adjusting the characteristics and sound quality of the speaker is provided with little characteristic variation. It is intended to do.

  The diaphragm of the present invention provides a method for producing a papermaking diaphragm with little variation by chemically modifying a hydroxyl group of a natural fiber with respect to waterproofness and flame retardancy.

That is, a speaker diaphragm manufacturing method comprising a modification step of modifying a hydroxyl group contained in natural fiber cellulose by a chemical reaction, a material defibrating step, and a paper making step of the defibrated material. The modification step of modifying the hydroxyl group contained in cellulose of natural fibers by a chemical reaction is a method for manufacturing a speaker diaphragm provided before the material defibrating step.

By using the method for manufacturing a speaker diaphragm of the present invention, a modification step for modifying the natural fiber itself is provided before the material defibration step, so that a waterproofing agent or Compared to the manufacturing method in which a flame retardant is applied, the effect of improving waterproofness and flame retardancy can be realized with less variation.

  Therefore, variation in the coating amount and variation in the coating position can be eliminated, thereby eliminating performance variation and ensuring stable waterproofness and flame retardancy.

  Furthermore, since the manufacturing process for applying a waterproofing agent or a flame retardant can be reduced after manufacturing the speaker diaphragm, the manufacturing cost can also be reduced.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
Hereinafter, the first, third, fifth, and sixth aspects of the present invention will be described using the first embodiment.

  FIG. 1 is a process chart showing a method for manufacturing a speaker diaphragm by papermaking according to an embodiment of the present invention.

  With reference to FIG.

  As shown in FIG. 1, the material for the speaker papermaking diaphragm is put into a speaker diaphragm production facility.

  Here, the material of the speaker papermaking diaphragm to be input mainly consists of natural fibers.

  As this natural fiber, wood pulp mainly used for coniferous trees, bamboo pulp which is bamboo fiber obtained from bamboo in consideration of the global environment is used.

  When bamboo fiber is used, it is advantageous in terms of the global environment compared to the use of conifers. Furthermore, in terms of performance and sound quality, the high rigidity of bamboo fiber makes it possible to extend the high frequency limit frequency. High good sound quality can be realized.

  Next, the modification | denaturation process which modify | denaturates the hydroxyl group which the cellulose of this natural fiber contains by a chemical reaction is provided, and waterproofness and a flame retardance are provided to natural fiber material itself.

  Here, the modification method is preferably a method using an acetylation step that can be easily modified or a trifluoroacetylation step excellent in waterproofness and flame retardancy.

  Since the acetylation process can be easily modified and has high productivity, there is less variation in coating amount and application position compared to conventional methods of applying a flame retardant or waterproofing agent after manufacturing a speaker diaphragm. Accordingly, there is no performance variation, and a speaker diaphragm capable of ensuring stable waterproofness and flame retardance can be realized at low cost.

  In addition to the above-mentioned acetylation process, the trifluoroacetylation process can secure more stable waterproofing and flame retardancy.

  Next, the natural fiber material itself, which has been provided with waterproofness and flame retardancy, is placed in a container for unraveling and finely defibrated by a defibration process.

  Next, this defibrated material is made by a paper making process on a mold and a metal mesh placed thereon to discharge only moisture, deposit the material, and form a shape as a speaker diaphragm. .

  Next, in the pressurizing step, the deposited speaker diaphragm material is heated and pressurized to evaporate the remaining water.

  Next, an unnecessary outermost peripheral portion and a central hole portion for inserting the voice coil are punched by a die by a punching process.

  Thus, the speaker diaphragm according to the present invention is completed.

  In addition, although the above demonstrated the process of the press diaphragm, it is the same except a pressurization process, the pressurization process is eliminated, ie, an oven diaphragm which is dried for about 1 to 2 days without pressing, so-called non-press It is good also as a manufacturing method as a diaphragm.

  Moreover, although the above demonstrated the manufacturing method when the modification | denaturation process was provided before the defibration process, you may provide a modification | denaturation process after the defibration process, and the same effect is acquired.

  As described above, the modification step of modifying the hydroxyl group contained in cellulose of natural fibers by a chemical reaction is a method for manufacturing a speaker diaphragm provided before or after the material defibration step, thereby providing waterproofing and Production time of speaker papermaking diaphragms with excellent flame retardancy can be greatly shortened.

  Therefore, variation in the coating amount and variation in the coating position can be eliminated, thereby eliminating performance variation and ensuring stable waterproofness and flame retardancy.

  Furthermore, since the manufacturing process of applying a flame retardant or a waterproofing agent can be reduced after manufacturing the speaker diaphragm, the manufacturing cost can also be reduced.

  Therefore, it is possible to establish an excellent speaker manufacturing method capable of shortening the manufacturing time while being a papermaking diaphragm capable of ensuring waterproofness and flame retardancy.

  As described above, the speaker papermaking diaphragm having a high degree of freedom in adjusting the characteristics and sound quality as a speaker can be provided with high productivity, and the price of the speaker can be reduced.

(Embodiment 2)
In the following, the second aspect of the present invention will be described with reference to the second, fourth, seventh and eighth aspects of the present invention.

  2 and 3 are process charts showing a method for manufacturing a diaphragm according to an embodiment of the present invention.

  2 and 3 will be described while omitting the same contents as those in the first embodiment.

  As shown in FIG. 2, the difference from Embodiment 1 is that a beating process is further provided between the defibrating process and the paper making process.

  This beating process is different from the series of beating processes from the input of materials that require a schedule of several days as described in the prior art to the state where paper can be made, and the material that has already been defibrated. Is a beating process performed to finely adjust the degree of fibrillation.

  Therefore, the process can be completed in several minutes to several hours.

  By providing this beating step, the defibrating state of the material is further uniformed and stabilized, and highly accurate papermaking can be performed.

  Furthermore, this beating step may include a microfibrillation beating step.

  By including this microfibrillation beating process, the degree of fibrillation can be further improved, and the entanglement of material fibers during papermaking can be further improved, so that an excellent diaphragm having high rigidity and toughness can be obtained. .

The above-described beating process and microfibrillation beating process are generally beaten with a beater, refiner, or mixer, but in order to further improve productivity, a twin screw kneader is used for the defibration process. Then, by using a bead mill or a pressure homogenizer in the microfibrillation beating process, a method for producing a speaker diaphragm containing a microfibrillated fiber having a BET specific surface area of 1 m ² / g or more is obtained. The defibrated state is made uniform and stabilized, and highly accurate papermaking can be performed in a short time.

  Moreover, as shown in FIG. 3, you may further provide the chip formation process which makes bamboo fiber into a chip | tip before a defibration process.

  By using this manufacturing method, the defibration process can be carried out with higher accuracy and speed more reliably, the degree of fibrillation can be further improved and stabilized, and the entanglement of material fibers during papermaking can be improved. Since it can be further improved, a more excellent diaphragm having high rigidity and toughness can be obtained.

  In addition, as an effect of using bamboo fiber as a natural fiber, bamboo fiber has high rigidity and the fiber is cylindrical and easy to beat, and bamboo grows quickly and grows quickly even after cutting, It is characterized by a fiber that has a low impact on the global environment in terms of preventing the spread of desertification and preventing floods, and is expected to have a great effect.

  By using the above manufacturing method, a papermaking diaphragm having high performance and good sound quality that can ensure waterproofness and flame retardancy can be provided with high productivity.

  By finely adjusting the degree of fibrillation, an excellent diaphragm having high accuracy and high rigidity and toughness can be obtained at low cost.

  Examples based on actual experiments will be described below.

  Examples of the present invention will be described below, but the present invention is not limited to the examples.

Example 1
After making bamboo fiber into chips, 100 g of the bamboo fiber made into chips was dispersed in DMAc (dimethylacetamide) and reacted with 2 g of lithium chloride at 100 ° C. for 1 hour.

  The bamboo fibers were separated and dried at 105 ° C. for 2 hours.

  After 650 ml of this bamboo fiber was beaten with a beater, paper was made at 180 ° C. for 1 minute to produce a 16 cm diameter speaker diaphragm.

(Example 2)
After 1 kg of chipped bamboo fiber was treated with a pressure kneader at 20 rpm for 6 minutes, it was acetylated in the same manner as in Example 1. The bamboo fiber after pressure kneading not subjected to acetylation treatment and the bamboo fiber acetylated by the method of the example are mixed so as to have a weight ratio of 1: 1. A diaphragm for a speaker having a diameter was prepared.

(Example 3)
A speaker diaphragm having a diameter of 16 cm was prepared in the same manner as in Example 2 except that the acetylation in Example 2 was changed to trifluoroacetylation.

Example 4
The trifluoroacetylated bamboo fiber of Example 2 was microfibrillated with a bead mill until the BET specific surface area was 1.1 m ² / g.

  Except for using half-trifluoroacetylated bamboo fiber of Example 3 (non-denaturing: trifluoroacetylated: microfibril fluoroacetylated = 2: 1: 1 weight ratio). A speaker diaphragm having a diameter of 16 cm was prepared in the same manner as in Example 3.

(Comparative Example 1)
A speaker diaphragm having a diameter of 16 cm was prepared in the same manner as in Example 1 except that the acetylation treatment was omitted from Example 1.

(Example 5)
The diaphragms of Examples 1 to 4 and Comparative Example 1 were incorporated into a speaker, and about 80% of water was added in the height direction of the diaphragm. The time for water to leak into the opposite part of the diaphragm was as follows.

(Effect of the invention)
From the above experimental results, it is understood that the speaker diaphragm manufactured by the speaker diaphragm manufacturing method of the present invention has improved waterproofness.

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

  FIG. 4 shows a cross-sectional view of a speaker diaphragm according to an embodiment of the present invention.

  FIG. 4 shows a speaker papermaking diaphragm manufactured by the manufacturing method according to the first or second embodiment.

  This papermaking diaphragm for speakers gives water resistance and flame retardancy by chemically modifying the natural fiber itself, and while it is a papermaking diaphragm, the manufacturing time can be shortened. In addition, it is possible to provide a loudspeaker paper diaphragm that can increase the degree of freedom of sound quality adjustment and ensure stable waterproofness and flame retardancy with high productivity. Can be achieved.

(Embodiment 4)
Hereinafter, the invention described in claim 10 of the present invention will be described using the fourth embodiment.

  FIG. 5 shows a cross-sectional view of a speaker according to an embodiment of the present invention.

  As shown in FIG. 5, a magnetized magnet 21 is sandwiched between an upper plate 22 and a yoke 23 to constitute an internal magnet type magnetic circuit 24.

  A frame 26 is coupled to the yoke 23 of the magnetic circuit 24. The outer periphery of the diaphragm 27 according to claim 9 is bonded to the peripheral edge of the frame 26 via an edge 29. One end of the voice coil 28 is coupled to the central portion of the diaphragm 27 and the opposite end is coupled so as to fit into the magnetic gap 25 of the magnetic circuit 24.

  In the above, the speaker having the inner magnet type magnetic circuit 24 has been described. However, the present invention is not limited to this, and may be applied to a speaker having an outer magnet type magnetic circuit.

  Further, the present invention can be applied to a small speaker in which the diaphragm 27 and the edge 29 are integrated.

  With this configuration, it is possible to realize a low-cost speaker that is excellent in sound quality using a papermaking diaphragm having waterproofness and flame retardancy and that can adjust characteristics and tone color with high accuracy.

  As another effect, the rigidity and toughness of the diaphragm are improved, and the speaker can be excellent in terms of quality, reliability, and environment.

  Therefore, it is possible to improve various reliability typified by high input resistance of the speaker, flame resistance, and moisture resistance reliability.

  Therefore, a speaker excellent in performance, quality, reliability, and environment can be provided at a low cost.

  The speaker diaphragm manufacturing method according to the present invention can be applied to a speaker diaphragm manufacturing method capable of achieving both high productivity capable of shortening the manufacturing time and cost reduction, although it is a papermaking diaphragm.

Process chart which shows the manufacturing method of the diaphragm for speakers in one embodiment of the present invention Process chart which shows the manufacturing method of the diaphragm for speakers in one embodiment of the present invention Process chart which shows the manufacturing method of the diaphragm for speakers in one embodiment of the present invention Sectional drawing of the diaphragm for speakers in one embodiment of this invention Sectional drawing of the speaker in one embodiment of this invention Process chart showing conventional method for manufacturing speaker diaphragm

Explanation of symbols

21 Magnet 22 Upper plate 23 Yoke 24 Magnetic circuit 25 Magnetic gap 26 Frame 27 Diaphragm 28 Voice coil 29 Edge

Claims (10)

A method for producing a speaker diaphragm comprising a modification step of modifying a hydroxyl group contained in natural fiber cellulose by a chemical reaction, a material defibrating step, and a paper making step of the defibrated material, The modification step is a method of manufacturing a speaker diaphragm provided before the defibration step. The method for manufacturing a speaker diaphragm according to claim 1, further comprising a beating step between the defibrating step and the paper making step. The method for manufacturing a speaker diaphragm according to claim 1 or 2, wherein the natural fiber is bamboo fiber. The method for manufacturing a speaker diaphragm according to any one of claims 1 to 3, further comprising a chip-forming step for converting bamboo fiber into a chip before the defibrating step. The method for manufacturing a speaker diaphragm according to any one of claims 1 to 4, wherein the modification step of modifying the hydroxyl group by a chemical reaction is an acetylation step. The method for manufacturing a speaker diaphragm according to claim 5, wherein the acetylation step is a trifluoroacetylation step. 3. The speaker diaphragm manufacturing method according to claim 2, wherein the beating step includes a microfibrillation beating step. The microfibrillated fiber having a BET specific surface area of 1 m ² / g or more is contained by using a biaxial kneader in the defibrating step and using a bead mill or a pressure homogenizer in the microfibrillating beating step. Manufacturing method for a speaker diaphragm. A speaker diaphragm manufactured by the method for manufacturing a speaker diaphragm according to any one of claims 1 to 8. A frame coupled to the magnetic circuit, a diaphragm for a speaker according to claim 9 coupled to an outer periphery of the frame, and a portion coupled to the diaphragm, and a part of the diaphragm being disposed in a magnetic gap of the magnetic circuit A speaker comprising a voice coil.

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